阅读说明：本技术 包括柔性振动模块的显示设备和制造柔性振动模块的方法 (Display device including flexible vibration module and method of manufacturing flexible vibration module ) 是由 申晟义 金泰宪 柳轻烈 张勇均 金治完 李用雨 高有善 于 2019-06-27 设计创作，主要内容包括：提供了包括柔性振动模块的显示设备和制造柔性振动模块的方法。一种显示设备包括：被配置成显示图像的像素面板和位于显示面板的后表面上的柔性振动模块,所述柔性振动模块被配置为使显示面板振动,所述柔性振动模块包括：多个第一部分,所述多个第一部分具有压电特性；以及多个第二部分,所述多个第二部分分别位于所述多个第一部分的对之间,所述多个第二部分具有柔性。(A display device including a flexible vibration module and a method of manufacturing the flexible vibration module are provided. A display device includes: a pixel panel configured to display an image and a flexible vibration module on a rear surface of the display panel, the flexible vibration module configured to vibrate the display panel, the flexible vibration module comprising: a plurality of first portions having piezoelectric properties; and a plurality of second portions respectively located between pairs of the plurality of first portions, the plurality of second portions having flexibility.)

1. A display device, comprising:

a display panel configured to display an image; and

a flexible vibration module on a rear surface of the display panel, the flexible vibration module configured to vibrate the display panel, the flexible vibration module comprising:

a plurality of first portions having piezoelectric properties; and

a plurality of second portions respectively located between respective pairs of the plurality of first portions, the plurality of second portions having flexibility.

2. The display device according to claim 1,

each of the plurality of first portions comprises a non-flexible inorganic material, and

each of the plurality of second portions comprises a flexible organic material.

3. The display device according to claim 2, wherein each of the plurality of first portions contains at least one of an organic piezoelectric material and an organic non-piezoelectric material.

4. The display device of claim 2, wherein the flexible organic material is configured to absorb an impact applied to the flexible vibration module or to the display device.

5. The display device according to claim 1,

the plurality of first portions and the plurality of second portions are juxtaposed on the same plane, and

the size of each of the plurality of first portions is the same as or different from the size of each of the plurality of second portions.

6. The display device according to claim 1, wherein each of the plurality of first portions has one of a linear shape, a circular shape, an oval shape, a triangular shape, and a polygonal shape.

7. The display device according to claim 1,

the plurality of first portions and the plurality of second portions are juxtaposed on the same plane, and

each successive second portion of the plurality of second portions decreases in size in a direction from the central portion to the peripheral portion of the flexible vibration module as compared to a previous one of the plurality of second portions.

8. The display device according to claim 7, wherein a second portion having a largest size among the plurality of second portions is located in the central portion of the flexible vibration module.

9. A display device, the display device comprising:

a flexible display panel capable of being spirally wound, unwound, or having a particular radius of curvature, the flexible display panel comprising a display area configured to display an image; and

a flexible vibration module located on a rear surface of the flexible display panel to correspond to the display area and bent based on unrolling or rolling of the display panel or bent based on a curvature of the flexible display panel, the flexible vibration module including:

a plurality of vibrating portions; and

a plurality of elastic portions respectively located between respective pairs of the plurality of vibration portions, the plurality of elastic portions having flexibility.

10. A method of manufacturing a flexible vibration module, the method comprising the steps of:

manufacturing a piezoelectric composite including a plurality of inorganic material portions and a plurality of organic material portions connected between the plurality of inorganic material portions, based on an inorganic material mother substrate having piezoelectric characteristics and an organic material having flexibility;

forming a first electrode layer on a first surface of the piezoelectric composite and a second electrode layer on a second surface of the piezoelectric composite;

applying a voltage to the first electrode layer and the second electrode layer in a temperature atmosphere to form a polarization of each of the plurality of inorganic material portions; and

forming a protective film on each of the first electrode layer and the second electrode layer.

Technical Field

The present disclosure relates to a display device, and more particularly, to a display device including a flexible vibration module and a method of manufacturing the flexible vibration module.

Background

Generally, in a display device, a display panel displays an image, and a separate speaker should be installed to provide sound. When the speaker is provided in the display device, the speaker occupies a space, and therefore, the design and spatial disposition of the display device are limited.

The speaker applied to the display device may be, for example, an actuator including a magnet and a coil. However, when the actuator is applied to a display device, the thickness of the display device is large. A piezoelectric element capable of achieving a thin thickness attracts much attention.

Since the piezoelectric element is fragile, the piezoelectric element is easily damaged by external impact, and thus, the reliability of sound reproduction is low.

Disclosure of Invention

Accordingly, the present disclosure is directed to a display device including a flexible vibration module and a method of manufacturing the same that substantially obviate one or more problems due to limitations and disadvantages of the related art.

An aspect of the present disclosure is to provide a display device including a flexible vibration module which is disposed on a rear surface of a display panel of the display device, vibrates the display panel to generate sound, and is superior in sound pressure characteristics and sound localization.

Another aspect of the present disclosure is to provide a display device including a flexible vibration module that is flexible. Therefore, it is applicable to various application fields such as a bending type display device, a rollable display device, a bendable display device, and a flexible display device.

Additional features and aspects will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the inventive concepts presented herein. Other features and aspects of the inventive concept can be realized and attained by the structure particularly pointed out in the written description (or claims hereof) and the appended drawings.

To achieve these and other aspects of the inventive concept, as embodied and broadly described, there is provided a display apparatus including: the display device includes a display panel configured to display an image, and a flexible vibration module on a rear surface of the display panel, the flexible vibration module configured to vibrate the display panel. The flexible vibration module may include a plurality of first portions having piezoelectric characteristics and a plurality of second portions respectively located between pairs of the plurality of first portions, the plurality of second portions having flexibility.

In another aspect, there is provided a display apparatus including: a flexible display panel capable of being spirally wound, unwound, or having a particular radius of curvature, the flexible display panel comprising a display area configured to display an image; and a flexible vibration module on a rear surface of the flexible display panel to correspond to a display area and to be bent based on unwinding or winding of the flexible display panel or to be bent based on a curvature of the flexible display panel. The flexible vibration module may include a plurality of vibration portions and a plurality of elastic portions respectively located between pairs of the plurality of vibration portions, the plurality of vibration portions having flexibility.

In another aspect, there is provided a method of manufacturing a flexible vibration module, the method comprising the steps of: manufacturing a piezoelectric composite including a plurality of inorganic material portions and a plurality of organic material portions connected between the plurality of inorganic material portions, based on an inorganic material mother substrate having piezoelectric characteristics and an organic material having flexibility; forming a first electrode layer on a first surface of the piezoelectric composite and a second electrode layer on a second surface of the piezoelectric composite; applying a voltage to the first electrode layer and the second electrode layer in a temperature atmosphere to form a polarization of each of the plurality of inorganic material portions; and forming a protective film on each of the first electrode layer and the second electrode layer.

It is to be understood that both the foregoing general description and the following detailed description of the present disclosure are exemplary and explanatory and are intended to provide further explanation of the disclosure as claimed.

Supplementary note 1. a display device, comprising:

a display panel configured to display an image; and

a flexible vibration module on a rear surface of the display panel, the flexible vibration module configured to vibrate the display panel, the flexible vibration module comprising:

a plurality of first portions having piezoelectric properties; and

a plurality of second portions respectively located between respective pairs of the plurality of first portions, the plurality of second portions having flexibility.

Supplementary note 2. the display device according to supplementary note 1, wherein,

each of the plurality of first portions comprises a non-flexible inorganic material, and

each of the plurality of second portions comprises a flexible organic material.

Note 3 the display device according to note 2, wherein each of the plurality of first portions contains at least one of an organic piezoelectric material and an organic non-piezoelectric material.

Supplementary note 4 the display device according to supplementary note 2, wherein the flexible organic material is configured to absorb an impact applied to the flexible vibration module or applied to the display device.

Supplementary note 5. the display device according to supplementary note 1, wherein,

the plurality of first portions and the plurality of second portions are juxtaposed on the same plane, and

the size of each of the plurality of first portions is the same as or different from the size of each of the plurality of second portions.

Supplementary note 6 the display device according to supplementary note 1, wherein each of the plurality of first portions has one of a linear shape, a circular shape, an oval shape, a triangular shape, and a polygonal shape.

Supplementary note 7. the display device according to supplementary note 1, wherein,

the plurality of first portions and the plurality of second portions are juxtaposed on the same plane, and

each successive second portion of the plurality of second portions decreases in size in a direction from the central portion to the peripheral portion of the flexible vibration module as compared to a previous one of the plurality of second portions.

Note 8 the display device according to note 7, wherein a second portion having a largest size among the plurality of second portions is located in the central portion of the flexible vibration module.

Supplementary note 9 the display device according to supplementary note 1, wherein each of the plurality of first portions has a triangular shape and is adjacent to another of the plurality of first portions to form a 2N-corner shape, where N is a natural number equal to or greater than 2.

Supplementary note 10 the display device according to supplementary note 1, wherein the flexible vibration module includes:

a first piezoelectric composite layer including a first set of the plurality of first portions and the plurality of second portions;

a common electrode on the first piezoelectric composite layer; and

a second piezoelectric composite layer on the common electrode, the second piezoelectric composite layer including a second set of the plurality of first portions and the plurality of second portions.

Note 11. the display device according to note 10, wherein each of the plurality of first portions on the second piezoelectric composite layer:

each overlapping a corresponding one of the plurality of second portions on the first piezoelectric composite layer; or

Each overlapping a corresponding one of the plurality of first portions on the first piezoelectric composite layer.

Supplementary note 12. the display device according to supplementary note 1, wherein,

the display panel includes:

a display area configured to display the image; and

a non-display area surrounding the display area, and

the flexible vibration module has a size 0.9 to 1.1 times that of the display area.

Note 13. the display device according to note 1, wherein,

the display panel includes a display area configured to display an image; and is

The flexible vibration module includes:

a first vibration module located in a first region of the display area, the first vibration module including a first group of the plurality of first portions and the plurality of second portions; and

a second vibration module located in a second region of the display area, the second vibration module including a second group of the plurality of first portions and the plurality of second portions.

Supplementary note 14. the display device according to supplementary note 13, wherein,

the flexible vibration module further includes:

a third vibration module alternately disposed with the first vibration module in the first region of the display region, the third vibration module including a third group of the plurality of first portions and the plurality of second portions; and

a fourth vibration module alternately disposed with the second vibration module in the second region of the display region, the fourth vibration module including a fourth group of the plurality of first portions and the plurality of second portions.

Supplementary note 15. the display device according to supplementary note 14, further comprising:

a first plate between the third vibration module and the display panel; and

a second plate between the fourth vibration module and the display panel.

Note 16 the display device according to note 13, wherein each of the plurality of first portions has a triangular shape and is disposed adjacent to another one of the plurality of first portions to form a 2N-corner shape, where N is a natural number equal to or greater than 2.

Note 17. the display device according to note 1, further comprising:

another flexible vibration module on the rear surface of the display panel, the other flexible vibration module configured to vibrate the display panel,

wherein the display panel includes:

in the first area, the first and second regions are arranged in a first plane,

a second region, and

a partition configured to divide the first region and the second region,

wherein the flexible vibration module is located in the first region, and

wherein the other flexible vibration module is located in the second region.

Supplementary note 18. the display device according to supplementary note 17, further comprising:

a third flexible vibration module and a fourth flexible vibration module on the rear surface of the display panel, each of the third flexible vibration module and the fourth flexible vibration module configured to vibrate the display panel,

wherein the third flexible vibration module is located in the first region and is diagonally disposed with respect to the flexible vibration module, and

wherein the fourth flexible vibration module is located in the second region and is diagonally disposed with respect to the other flexible vibration module.

Supplementary note 19. a display device, comprising:

a flexible display panel capable of being spirally wound, unwound, or having a particular radius of curvature, the flexible display panel comprising a display area configured to display an image; and

a flexible vibration module located on a rear surface of the flexible display panel to correspond to the display area and bent based on unrolling or rolling of the display panel or bent based on a curvature of the flexible display panel, the flexible vibration module including:

a plurality of vibrating portions; and

a plurality of elastic portions respectively located between respective pairs of the plurality of vibration portions, the plurality of elastic portions having flexibility.

Supplementary note 20. the display device according to supplementary note 19, wherein,

each of the plurality of vibrating portions includes a non-flexible inorganic material having piezoelectric characteristics; and is

Each of the plurality of resilient portions comprises a flexible material including at least one of an organic piezoelectric material and an organic non-piezoelectric material.

Supplementary note 21 the display device according to supplementary note 20, wherein the flexible material is configured to absorb an impact applied to the flexible vibration module or applied to the display device.

Supplementary note 22. the display device according to supplementary note 19, wherein,

the plurality of vibrating portions and the plurality of elastic portions are juxtaposed on the same plane, and

the size of each of the plurality of vibration parts is the same as or different from the size of each of the plurality of elastic parts.

Supplementary note 23. the display device according to supplementary note 19, the display device further comprising:

another flexible vibration module on the rear surface of the flexible display panel to correspond to the display area and to be bent based on unrolling or rolling of the flexible display panel or to be bent based on a curvature of the flexible display panel,

wherein the flexible display panel includes:

in the first area, the first and second regions are arranged in a first plane,

a second region, and

a partition configured to divide the first region and the second region,

wherein the flexible vibration module is located in the first region, and

wherein the other flexible vibration module is located in the second region.

Supplementary note 24 the display device according to supplementary note 23, further comprising:

a third flexible vibration module and a fourth flexible vibration module on the rear surface of the flexible display panel to correspond to the display area and to be bent based on unrolling or rolling of the flexible display panel or to be bent based on a curvature of the flexible display panel,

wherein the third flexible vibration module is located in the first region and is diagonally disposed with respect to the flexible vibration module, and

wherein the fourth flexible vibration module is located in the second region and is diagonally disposed with respect to the other flexible vibration module.

Supplementary note 25. a method of manufacturing a flexible vibration module, the method comprising the steps of:

manufacturing a piezoelectric composite including a plurality of inorganic material portions and a plurality of organic material portions connected between the plurality of inorganic material portions, based on an inorganic material mother substrate having piezoelectric characteristics and an organic material having flexibility;

forming a first electrode layer on a first surface of the piezoelectric composite and a second electrode layer on a second surface of the piezoelectric composite;

applying a voltage to the first electrode layer and the second electrode layer in a temperature atmosphere to form a polarization of each of the plurality of inorganic material portions; and

forming a protective film on each of the first electrode layer and the second electrode layer.

Supplementary notes 26. the method according to supplementary notes 25, wherein, each of the plurality of inorganic material portions has a triangular shape and is adjacent to another of the plurality of inorganic material portions to form a 2N-angle shape, wherein N is a natural number equal to or greater than 2.

Reference numeral 27, the method according to reference numeral 25, wherein the step of manufacturing the piezoelectric composite includes the steps of:

manufacturing a laminated composite by repeating the following process;

a process of forming a flexible organic material layer on the inorganic material mother substrate; and

a process of laminating another inorganic material mother substrate on the flexible organic material layer,

curing the flexible organic material layer laminated on the laminated composite; and

cutting the laminated composite to a size to manufacture the piezoelectric composite having a film type,

wherein each inorganic material mother substrate comprises a non-flexible material.

Reference numeral 28, the method according to reference numeral 25, wherein the step of manufacturing the piezoelectric composite includes the steps of:

placing the inorganic material mother substrate on a rotatable stage;

aligning a cutting region of the inorganic material mother substrate and a cutting path of a cutting device by rotation and linear movement of the rotatable stage based on a plurality of cutting regions defined in the inorganic material mother substrate and the cutting path of the cutting device, and patterning the inorganic material mother substrate into the plurality of inorganic material portions by a cutting process of sequentially cutting the aligned cutting regions of the inorganic material mother substrate;

placing a frame comprising an opening on the rotatable gantry; and

filling and curing an organic material between the plurality of inorganic material portions and between each of the plurality of inorganic material portions and the opening of the frame to form the plurality of organic material portions.

Supplementary note 29. the method according to supplementary note 28, wherein,

the plurality of cutting regions comprises:

a plurality of lengthwise cutting zones;

cutting the area in the width direction;

a plurality of first diagonal cutting zones; and

a plurality of second diagonal cutting zones, and

the cutting process includes the following processes:

a first cutting process of cutting each of the plurality of lengthwise cutting regions;

a second cutting process of cutting the width direction cutting region;

a third cutting process of cutting each of the plurality of first diagonal direction cutting regions; and

a fourth cutting process of cutting each of the plurality of second diagonal direction cutting regions.

Drawings

The accompanying drawings, which are included to provide a further understanding of the disclosure and are incorporated in and constitute a part of this specification, illustrate embodiments of the disclosure and together with the description serve to explain various principles of the disclosure.

Fig. 1 is a perspective view of a display device according to an embodiment of the present disclosure.

Fig. 2 is a sectional view taken along line I-I' shown in fig. 1.

Fig. 3 is a sectional view of a flexible vibration module of a display device according to an embodiment of the present disclosure.

Fig. 4 is a diagram illustrating a piezoelectric composite layer according to a first embodiment of the present disclosure.

Fig. 5A is a view illustrating an example in which both ends of the piezoelectric composite layer of fig. 4 are folded upward.

Fig. 5B is a view illustrating an example in which both ends of the piezoelectric composite layer of fig. 4 are folded downward.

Fig. 6 is a diagram illustrating a piezoelectric composite layer according to a second embodiment of the present disclosure.

Fig. 7 is a diagram illustrating a piezoelectric composite layer according to a third embodiment of the present disclosure.

Fig. 8 is a diagram illustrating a piezoelectric composite layer according to a fourth embodiment of the present disclosure.

Fig. 9 is a view illustrating an example in which both ends of the piezoelectric composite layer of fig. 8 are folded downward.

Fig. 10 is a diagram illustrating a piezoelectric composite layer according to a fifth embodiment of the present disclosure.

Fig. 11 is a diagram illustrating a piezoelectric composite layer according to a sixth embodiment of the present disclosure.

Fig. 12 is a diagram illustrating an embodiment of the piezoelectric composite layer shown in fig. 11.

Fig. 13 is a diagram illustrating a flexible vibration module according to another embodiment of the present disclosure.

Fig. 14 is a perspective view of a display device according to another embodiment of the present disclosure.

Fig. 15 is a diagram illustrating a first vibration module and a second vibration module located on a rear surface of the display panel shown in fig. 14.

Fig. 16 is a diagram illustrating a first modified embodiment of each of the first and second vibration modules shown in fig. 15.

Fig. 17 is a diagram illustrating a second modified embodiment of each of the first and second vibration modules shown in fig. 15.

Fig. 18 is a diagram illustrating an example of each of the first to fourth vibration modules located on the rear surface of the display panel shown in fig. 14.

Fig. 19A to 19C are diagrams illustrating various display devices to which the flexible vibration module according to the embodiment of the present disclosure may be applied.

Fig. 20A to 20C are diagrams illustrating a method of manufacturing a flexible vibration module according to an embodiment of the present disclosure.

Fig. 21A to 21D are views illustrating a method of manufacturing a flexible vibration module according to another embodiment of the present disclosure.

Fig. 22A to 22F are views illustrating a method of manufacturing a flexible vibration module according to another embodiment of the present disclosure.

Fig. 23 is a graph showing an experimental result of sound pressure characteristics based on the presence or absence of the display panel having the flexible vibration module provided according to the first embodiment and the thin film speaker provided according to the comparative example.

Fig. 24 is a graph illustrating an experimental result of sound pressure characteristics of an organic light emitting diode display panel to which the flexible vibration module according to the first to third embodiments of the present disclosure is attached.

Fig. 25 is a graph illustrating an experimental result of sound pressure characteristics of an organic light emitting diode display panel having the flexible vibration module according to the first to fourth embodiments of the present disclosure attached thereto.

Throughout the detailed description and the specification, unless otherwise noted, like reference numerals shall be understood to refer to like elements, features and structures. The relative dimensions and descriptions of these elements may be exaggerated for clarity, illustration, and convenience.

Detailed Description

Reference will now be made in detail to embodiments of the present disclosure, examples of which are illustrated in the accompanying drawings.

In the following description, when it is determined that a detailed description of known functions or configurations related to this document unnecessarily obscures the gist of the present inventive concept, the detailed description thereof will be omitted. The sequence of process steps and/or operations described is an example; however, as is known in the art, the order of the steps and/or operations is not limited to the order set forth herein but may be changed unless the steps and/or operations are necessarily presented in a particular order. Like reference numerals refer to like elements throughout. The names of the respective elements used in the following description are selected only for convenience of writing the specification, and thus may be different from those used in an actual product.

It will be understood that, although the terms first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element, without departing from the scope of the present disclosure.

The term "at least one" should be understood to include any and all combinations of one or more of the associated listed items. For example, the meaning of "at least one of the first item, the second item, the third item" means a combination of all items set forth from two or more of the first item, the second item, and the third item, as well as the first item, the second item, or the third item.

In the description of the embodiments, when one structure is described as being located "above or" over "or" below or "beneath" another structure, the description should be construed as including a case where the structures are in contact with each other and a case where a third structure is interposed therebetween. The size and thickness of each element shown in the drawings are given only for convenience of description, and embodiments of the present disclosure are not limited thereto.

As can be fully appreciated by those skilled in the art, the features of the various embodiments of the present disclosure may be partially or wholly coupled or combined with each other, and may variously interoperate with each other and be technically driven. Embodiments of the present disclosure may be performed independently of each other or may be performed together in an interdependent relationship.

Hereinafter, a display apparatus according to an embodiment of the present disclosure will be described in detail with reference to the accompanying drawings. When a reference numeral is added to an element of each drawing, the same reference numeral may refer to the same element although the same element is shown in other drawings. In order for the display device to provide sound, the speaker may be implemented in a film type. The film type vibration module may be manufactured to have a large area and may be applied to a display apparatus having a large area. However, since the piezoelectric characteristics of the film type vibration module are low, it may be difficult to apply the film type vibration module to a large area due to low vibration. When ceramics are used to enhance piezoelectric characteristics, the film type vibration module may have poor durability, and the size of the ceramics may be limited. When a vibration module including a piezoelectric composite including piezoelectric ceramics is applied to a display device, since the piezoelectric composite vibrates in a horizontal direction related to a left-right direction (e.g., a horizontal direction related to a left-right direction of the display device), the display device may not be sufficiently vibrated in a vertical (e.g., front-back) direction. Therefore, it may be difficult to apply the vibration module to the display device, and a desired sound may not be output to a front area in front of the display device. When the film type piezoelectric is applied to a display device, the sound pressure characteristic thereof may be lower than that of a general speaker such as an exciter. When a stacked film type piezoelectric in which film type piezoelectrics are configured with a plurality of layers in order to improve sound pressure is applied to a display device, power consumption may increase.

Therefore, the inventors have conducted various experiments to realize a vibration module for enhancing piezoelectric characteristics, rigidity, and flexibility. For example, the inventors have recognized that when the vibration module is formed of a composite member containing a filler having a high dielectric constant, the piezoelectric characteristics are low, and thus desired sound cannot be realized. Through various experiments, the inventors have recognized that the vibration module should be formed of a piezoelectric ceramic so as to have piezoelectric characteristics, and should be formed of an organic material so as to ensure rigidity and flexibility. Through various experiments, the inventors have recognized that the vibration module should be formed of a piezoelectric ceramic so as to have piezoelectric characteristics, and should be formed of a material such as a polymer so as to solve the brittleness of the piezoelectric ceramic. The inventors have recognized that when the vibration module is configured such that a material such as a polymer is included in the piezo ceramic composite, the vibration module has flexibility. Accordingly, the inventors have invented a display device including a vibration module having a new structure for enhancing piezoelectric characteristics, rigidity, and flexibility. This will be described below.

According to the embodiments of the present disclosure, the flexible vibration module may be manufactured to have good sound pressure characteristics, good sound localization characteristics, and flexibility characteristics, and may not be easily damaged by external impact. The display device may include the flexible vibration module, thereby enhancing reliability and consumer satisfaction. The display device may be one of a curved display device, a rollable display device, a flexible display device and a flexible display device. According to an embodiment of the present disclosure, the flexible vibration module may have various shapes such as a two-dimensional (2D) shape and a three-dimensional (3D) shape based on flexibility, and a method of manufacturing the flexible vibration module may be provided.

Fig. 1 is a perspective view of a display device according to an embodiment of the present disclosure. Fig. 2 is a sectional view taken along line I-I' shown in fig. 1.

Referring to fig. 1 and 2, a display device according to an embodiment of the present disclosure may include a display panel 100 and a flexible vibration module 200 on a rear surface of the display panel 100. The rear surface may refer to a surface of the display panel opposite to a front surface of the display panel including a display area for displaying an image.

The display panel 100 may be a bending type display panel or may be any type of display panel such as a liquid crystal display panel, an organic light emitting display panel, a quantum dot light emitting display panel, a micro light emitting diode display panel, and an electrophoretic display panel. For example, if the display panel 100 is vibrated by the flexible vibration module 200 to generate a sound wave (e.g., sound) or to generate a tactile feedback in response to a touch, the embodiment of the display panel 100 is not limited to a specific display panel.

The display panel 100 according to an embodiment may include: a Thin Film Transistor (TFT) array substrate including a plurality of pixels defined by a plurality of gate lines and a plurality of data lines and a TFT in each of the plurality of pixels to drive each of the plurality of pixels; a light emitting device layer on the TFT array substrate; and an encapsulation substrate covering the light emitting device layer. For example, the encapsulation substrate may protect the TFT and the light emitting device layer from external impact, and may reduce or prevent water from penetrating into the light emitting device layer.

The display panel 100 according to an embodiment may include a display area AA for displaying an image according to driving of a plurality of pixels and a non-display area BA surrounding the display area AA.

The display panel 100 according to the embodiment may include a bent portion, which may be bent or curved to have a curved shape or a certain radius of curvature.

The bent portion of the display panel 100 may be located in at least one of one edge (e.g., a peripheral edge) and another edge (e.g., a peripheral edge) of the display panel 100 that are parallel to each other. One edge and/or the other edge of the display panel 100 where the bending portion is implemented may include only the non-display area BA or may include edges or peripheral edges of the display area AA and the non-display area BA. For example, the display panel 100 including the bending part implemented by the bending of the non-display area BA may have a single-sided bezel bending structure or a two-sided bezel bending structure. In addition, the display panel 100 including the bent portion implemented by bending the edges or the peripheral edges of the display area AA and the non-display area BA may have a single-sided active bending structure or a double-sided active bending structure.

The display apparatus according to the embodiment of the present disclosure may further include a rear structure 300 supporting the display panel 100, and a panel fixing member 400 between the display panel 100 and the rear structure 300.

The rear structure 300 may be referred to as, for example, a cover bottom, a base plate, a rear cover, a chassis, a metal frame, a metal chassis, a chassis base, or an m-chassis. Accordingly, the rear structure 300 may be a support that supports the display panel 100, and may be any type of frame or plate structure each located on the rear surface of the display apparatus.

The rear structure 300 according to the embodiment may cover the entire rear surface of the display panel 100 with a gap space GS between the rear structure 300 and the display panel 100. For example, the rear structure 300 may include at least one of a glass material, a metal material, and a plastic material each having a plate shape. For example, the edge or the sharp corner of the rear structure 300 may have an inclined shape or a curved shape by, for example, a chamfering process or a rounding process. For example, the glass material of the rear structure 300 may be sapphire glass. As another example, the rear structure 300 including the metal material may include one or more of aluminum (Al), an Al alloy, a magnesium (Mg) alloy, and an iron (Fe) -nickel (Ni) alloy.

The rear structure 300 according to an embodiment may additionally cover a side surface of the display panel 100. For example, the rear structure 300 may include a rear cover part 310 covering the entire rear surface of the display panel 100 with a gap space GS with the display panel 100, and a side cover part 330 connected to one end of the rear cover part 310 and covering the entire side surface of the display panel 100. However, the embodiment is not limited thereto, and the rear cover part 310 and the side cover part 330 of the rear structure 300 may be integrated into one body.

The side cover part 330 may be implemented as a separate middle frame coupled, or may be connected with the rear cover part 310. For example, the side cover part 330 implemented as a middle frame may cover the rear cover part 310, and may cover, for example, all of a side surface of the rear cover part 310 and a side surface of the display panel 100. For example, the side cover part 330 implemented as the middle frame may include the same or different material as that of the rear cover part 310.

The rear structure 300 according to one embodiment may be coupled or connected to a rear edge or a peripheral edge of the display panel 100 by using the panel fixing member 400.

The panel fixing member 400 may be located between a rear edge or circumference of the display panel 100 and an edge or circumference of the rear structure 300, and may attach the display panel 100 to the rear structure 300. The panel fixing member 400 according to the embodiment may be implemented with a double-sided tape, a single-sided tape, or a double-sided tape foam pad, but the embodiment is not limited thereto.

The display apparatus according to the embodiment of the present disclosure may further include a front structure 500 covering the non-display area BA of the display panel 100.

The front structure 500 may have a frame shape that may include an opening overlapping the display area AA of the display panel 100. For example, the front structure 500 may be coupled or connected to the rear cover part 310 or the middle frame, and may cover the non-display area BA of the display panel 100, thereby supporting or fixing the display panel 100. The front structure 500 may be located at a front edge or a periphery of the display panel 100 and may be directly exposed (visible) to a user (e.g., a viewer). Accordingly, the aesthetic design appearance of the display device may be reduced, and the bezel width of the display device may be increased. To solve such a problem, according to an embodiment of the present disclosure, the display panel 100 may be coupled or connected to the rear structure 300 by the panel fixing member 400. Accordingly, the front structure 500 may be omitted (or removed), thereby reducing the bezel width of the display device and enhancing the aesthetic design appearance of the display device.

The flexible vibration module 200 may be located on a rear surface (e.g., a rear surface) of the display panel 100. The flexible vibration module 200 may be attached on the rear surface of the display panel 100 by the adhesive member 150.

The adhesive member 150 according to one embodiment may be located between the rear surface of the display panel 100 and the flexible vibration module 200. For example, the adhesive member 150 may attach the flexible vibration module 200 to the rear surface of the display panel 100, and may be an adhesive or a double-sided tape including an adhesive layer having good adhesive force or adhesion. For example, the adhesive layer of the adhesive member 150 may include one or more of epoxy, acrylic, silicone, or polyurethane, but the embodiment is not limited thereto. The adhesive layer of the adhesive member 150 may further include additives such as a tackifier or an adhesion enhancer, a wax component, or an antioxidant. The additive may prevent or reduce the adhesive member 150 from being separated (peeled) from the display panel 100 due to the vibration of the vibration module 200. For example, the tackifier may be a rosin derivative or the like, the wax component may be a paraffin wax or the like, and the antioxidant may be a phenol-based antioxidant such as thioester. However, the embodiment is not limited thereto.

According to another example, the adhesive member 150 may further include a hollow portion between the display panel 100 and the flexible vibration module 200. The hollow portion of the adhesive member 150 may provide an air gap between the display panel 100 and the flexible vibration module 200. Due to the air gap, acoustic waves (e.g., sound pressure) based on the vibration of the flexible vibration module 200 are not dispersed by the adhesive member 150, but may be concentrated on the display panel 100. Accordingly, it is possible to minimize or reduce the loss of the vibration caused by the adhesive member 150, thereby improving the sound pressure characteristic of the sound generated based on the vibration of the display panel 100.

The flexible vibration module 200 may be implemented as a film type. The thickness of the flexible vibration module 200 may be thinner than that of the display panel 100. Therefore, the thickness of the display panel 100 is not increased despite the presence of the flexible vibration module 200. The flexible vibration module 200 may be referred to as, for example, "sound generation module", "sound generation device", "thin film actuator", "film type piezoelectric composite actuator", "thin film speaker", "film type piezoelectric speaker", or "film type piezoelectric composite speaker", which use the display panel 100 as a vibration plate, but the term is not limited thereto.

In order to ensure the piezoelectric characteristics, the flexible vibration module 200 may include piezoelectric ceramics. In order to improve the impact resistance of the piezoelectric ceramic and achieve flexibility, the flexible vibration module 200 may include a material such as a polymer in the piezoelectric ceramic.

The flexible vibration module 200 according to an embodiment may include a plurality of first portions 210 and a plurality of second portions 220.

The plurality of first portions 210 according to an embodiment may each be configured as an inorganic material portion. The inorganic material portion may comprise a non-flexible material. The inorganic material portion may comprise an electroactive material. The electroactive material may have the following characteristics: when pressure or distortion (or bending) is applied to the crystal structure by an external force, a potential difference is generated due to dielectric polarization caused by a relative positional change of the positive (+) ions and the negative (-) ions, and vibration is generated by an electric field based on a voltage applied thereto.

Each of the plurality of second portions 220 may be alternately positioned between pairs of the plurality of first portions 210. The plurality of first portions 210 and the plurality of second portions 220 may be juxtaposed (or arranged) on the same plane (or the same layer). Each of the plurality of second portions 220 may be configured to fill a gap or space between two adjacent first portions of the plurality of first portions 210, and may be connected or attached to the first portion 210 adjacent thereto. Accordingly, in the flexible vibration module 200, vibration energy based on linkage in the unit cell of each first portion 210 may be increased by the corresponding second portion 220. Therefore, vibration can be increased and the piezoelectric property and flexibility can be ensured. In addition, in the flexible vibration module 200, the second portions 220 and the first portions 210 may be alternately disposed on the same plane along the length direction X with respect to one side of the flexible vibration module 200, and thus a large-area composite film (e.g., an organic/inorganic composite film) having a single-layer structure may be configured. Accordingly, the large area composite film may have flexibility due to the plurality of second portions 220.

Each of the plurality of second portions 220 according to an embodiment may be configured as an organic material portion, and may fill a space between inorganic material portions as the first portion 210. Each organic material portion may comprise a flexible material. Each organic material portion may be located between a plurality of inorganic material portions, may absorb an impact or shock applied to the inorganic material portion (e.g., the first portion), may release stress concentrated on the inorganic material portion to enhance overall durability of the flexible vibration module 200, and may provide flexibility to the flexible vibration module 200. The flexible vibration module 200 may have flexibility. The flexibility may be provided by a flexible organic portion rather than a non-flexible inorganic portion. The flexible vibration module 200 may be bent into a shape matching the shape of the display panel 100. The flexible vibration module 200 may vibrate according to an electrical signal to vibrate the display panel 100. For example, the flexible vibration module 200 may vibrate according to a voice signal synchronized with an image displayed by the display panel 100 to vibrate the display panel 100. As another example, the flexible vibration module 200 may be located on the display panel 100 and may vibrate according to a haptic feedback signal (e.g., a tactile feedback signal) synchronized with a user touch applied to a touch pad (e.g., a touch sensor layer) embedded in the display panel 100 to vibrate the display panel 100. Accordingly, the display panel 100 may vibrate based on the vibration of the flexible vibration module 200 to provide at least one of sound and tactile feedback to a user (e.g., a viewer). The embodiments are not limited to the above examples.

Accordingly, an impact transmitted to the inorganic material portion may be absorbed by the organic material portion, thereby reducing or preventing the inorganic material portion from being damaged by an external impact applied to the display device and reducing or minimizing a reduction in vibration performance (e.g., a reduction in sound performance) caused by the damage.

In addition, the flexible vibration module 200 of the display device according to the embodiment of the present disclosure may include a piezoelectric ceramic having a perovskite crystal structure. Accordingly, the flexible vibration module 200 may vibrate (via mechanical displacement) in response to an electrical signal applied from the outside. For example, when an Alternating Current (AC) voltage is applied to the inorganic material portion (e.g., the first portion 210), the inorganic material portion may alternately contract and expand based on the inverse piezoelectric effect. Accordingly, the flexible vibration module 200 may vibrate based on a bending phenomenon in which a bending direction is alternately changed, thereby causing the display panel 100 to vibrate based on the vibration of the flexible vibration module 200 to provide sound and/or tactile feedback to a user.

In addition, the flexible vibration module 200 according to the embodiment may have a size corresponding to the display area AA of the display panel 100. The size of the flexible vibration module 200 may be 0.9 to 1.1 times the size of the display area AA, but the embodiment is not limited thereto. For example, the flexible vibration module 200 may have the same or approximately the same size as the display area AA of the display panel 100. Accordingly, the flexible vibration module 200 may cover most of the display panel 100. In addition, the vibration generated by the flexible vibration module 200 may vibrate the entire display panel 100. Therefore, the localization of sound can be high and the satisfaction of the user can be improved. In addition, a contact area (e.g., a panel coverage) between the display panel 100 and the flexible vibration module 200 may be increased. Accordingly, the vibration area of the display panel 100 may be increased, thereby improving the midtone vocal band and/or the low-tone vocal band generated based on the vibration of the display panel 100. In addition, in a large-sized display device, the entire display panel 100 having a large size (e.g., a large area) may vibrate. Accordingly, sound localization based on vibration of the display panel 100 can be further enhanced, thereby realizing a stereo sound effect.

Accordingly, the flexible vibration module 200 according to the embodiment of the present disclosure may be located on the rear surface of the display panel 100 to sufficiently vibrate the display panel 100 in a vertical (e.g., front-to-rear) direction to output a desired sound to a front region in front of the display device. In addition, the material in the flexible vibration module 200 may be implemented in a patterned shape including an organic material portion and an inorganic material portion. Accordingly, the area (e.g., size) of the flexible vibration module 200 may be infinitely increased, and thus the panel coverage of the flexible vibration module 200 may be increased with respect to the display panel 100 to enhance the sound characteristics based on the vibration of the display panel 100. In addition, the flexible vibration module 200 may be thinned, thereby reducing or preventing an increase in driving voltage. For example, the flexible vibration module 200 may be configured to have a wide area corresponding to the same size as that of the display panel 100. Therefore, the sound pressure characteristic of a low-pitched sound band, which is a drawback of the film type piezoelectric, can be improved, and the driving voltage can be reduced. In addition, the flexible vibration module 200 according to an embodiment of the present disclosure may include an inorganic material portion and an organic material portion, and may be implemented as a film type. Thus, the flexible vibration module 200 may be integrated into or provided in a display device without interference from mechanical and/or other elements of the display device.

Fig. 3 is a sectional view of a flexible vibration module of a display device according to an embodiment of the present disclosure.

Referring to fig. 3 in conjunction with fig. 2, the flexible vibration module 200 may include a piezoelectric composite layer PCL, a first electrode layer 230, and a second electrode layer 240.

The piezoelectric composite layer PCL may include a plurality of first portions 210 and a plurality of second portions 220 each disposed between the plurality of first portions 210.

Each of the plurality of first portions 210 may include a polygonal pattern. For example, the plurality of first portions 210 may each include a line pattern having a first width d1, may be spaced apart from each other by a second width d2 (e.g., a certain interval) in the first direction X, and may be parallel in the second direction Y crossing the first direction X. Each of the plurality of first portions 210 may have the same size (e.g., the same width, area, or volume) within a range of process errors (e.g., allowable errors or tolerances) that occur in the manufacturing process.

Each of the plurality of first portions 210 according to the embodiment may include an inorganic material or a piezoelectric material each vibrating based on a piezoelectric effect (e.g., piezoelectric characteristics) caused by an electric field. For example, each of the plurality of first portions 210 may be referred to as, for example, an electro-active portion, an inorganic material portion, a piezoelectric material portion, or a vibration portion, but the embodiment is not limited thereto.

Each of the plurality of first portions 210 according to an embodiment may include a ceramic-based material for generating relatively high vibration, or may include a piezoelectric ceramic having a perovskite-based crystal structure. The perovskite crystal structure may have a piezoelectric effect and an inverse piezoelectric effect, and may be a plate-like structure having an orientation. The perovskite crystal structure may be represented by the chemical formula "ABO₃"means. In the chemical formula, "a" may include a divalent metal element, and "B" may include a tetravalent metal element. For example, in the formula "ABO₃"in," A "and" B "can be cations and" O "can be anions. For example, the formula "ABO₃"may include titanic acidLead (PbTiO)₃) Lead zirconate (PbZrO)₃) Barium titanate (BaTiO)₃) And strontium titanate (SrTiO)₃) But the embodiment is not limited thereto.

When the perovskite crystal structure includes a central ion (e.g., PbTiO)₃) When it is, the position of titanium (Ti) ions may be changed by external stress or a magnetic field. Thus, the polarization can be changed, thereby generating a piezoelectric effect. For example, in the perovskite crystal structure, the cubic shape corresponding to the symmetric structure may be changed to a tetragonal structure, an orthorhombic structure, or a rhombohedral structure corresponding to the asymmetric structure. Thus, a piezoelectric effect can be generated. In the tetragonal structure, the orthogonal structure, or the rhombohedral structure corresponding to the asymmetric structure, polarization may be higher in the morphotropic phase boundary, and readjustment of polarization may be easy, whereby the perovskite crystal structure may have high piezoelectric characteristics.

For example, the inorganic material portion disposed in each of the plurality of first portions 210 may include a material including one or more of lead (Pb), zirconium (Zr), titanium (Ti), zinc (Zn), nickel (Ni), and niobium (Nb), but the embodiment is not limited thereto.

As another example, the inorganic material portion disposed in each of the plurality of first portions 210 may include a lead zirconate titanate (PZT) -based material containing lead (Pb), zirconium (Zr), and titanium (Ti), or may include a lead nickel zirconate niobate (PZNN) -based material containing lead (Pb), zinc (Zn), nickel (Ni), and niobium (Nb), but the embodiment is not limited thereto. In addition, the inorganic material portion may include calcium titanate (CaTiO) containing no Pb at all₃)、BaTiO₃And SrTiO₃But the embodiment is not limited thereto.

Each of the plurality of second portions 220 may include a polygonal pattern. Each of the plurality of second portions 220 may be located between the plurality of first portions 210. The plurality of first portions 210 and the plurality of second portions 220 may be disposed (or arranged) side by side on the same plane (or the same layer). Each of the plurality of second portions 220 may fill a gap between two adjacent first portions of the plurality of first portions 210, and may be connected or attached to the first portion 210 adjacent thereto. For example, the plurality of second portions 220 may each include a line pattern having a second width d2 and may be juxtaposed with the first portion 210 therebetween. Each of the plurality of second portions 220 may have the same size (e.g., the same width, area, or volume) within a range of process errors (e.g., allowable errors or tolerances) that occur in the manufacturing process.

The size of each of the second portions 220 may be the same as or different from the size of each of the first portions 210. For example, the size of each first portion 210 and the size of each second portion 220 may be adjusted based on desired conditions of the flexible vibration module 200 including vibration characteristics and/or flexibility.

Each of the plurality of second portions 220 may have a modulus and viscoelasticity lower than that of each of the first portions 210. Accordingly, the plurality of second portions 220 may enhance the reliability of each first portion 210 that is vulnerable to impact due to fragility. For example, when the flexible vibration module 200 for vibrating the display panel 100 has impact resistance and high rigidity, the flexible vibration module 200 may have high vibration characteristics or maximum vibration characteristics. In order to provide the flexible vibration module 200 with impact resistance and high rigidity, the plurality of second portions 220 may each include a material having a relatively high damping factor (tan δ) and relatively high rigidity. For example, the plurality of second portions 220 may each comprise a material having a damping factor (tan δ) of about 0.1[ Gpa ] to about 1[ Gpa ] and a relatively high stiffness of about 0[ Gpa ] to about 10[ Gpa ]. In addition, the damping factor (tan δ) and the stiffness characteristic can be described based on the correlation between the loss coefficient and the modulus. For example, the plurality of second portions 220 may each comprise a material having a loss factor of about 0.01 to about 1 and a modulus of about 1[ Gpa ] to about 10[ Gpa ].

The organic material portion in each of the plurality of second portions 220 may include an organic material or an organic polymer each having a flexible characteristic, as compared to the inorganic material portion of each of the first portions 210. For example, each of the plurality of second portions 220 may include one or more of an organic material, an organic polymer, an organic piezoelectric material, and an organic non-piezoelectric material. For example, each of the plurality of second portions 220 may be referred to as, for example, an adhesive portion, an elastic portion, a bending portion, a damping portion, or a flexible portion, but the embodiment is not limited thereto.

The organic material portion according to an embodiment may include at least one of an organic piezoelectric material and an organic non-piezoelectric material.

The organic material portion including the organic piezoelectric material may absorb an impact applied to the inorganic material portion (e.g., the first portion 210). accordingly, the organic material portion may enhance the overall durability of the flexible vibration module 200 and may provide piezoelectric characteristics corresponding to a specific level or higher.

The organic material portion comprising the organic non-piezoelectric material may include a curable resin composition and an adhesive comprising the curable resin composition. Accordingly, the organic material portion may absorb the impact applied to the inorganic material portion (e.g., the first portion), thereby enhancing the overall durability of the flexible vibration module 200. The organic non-piezoelectric material according to an embodiment may include at least one of an epoxy-based polymer, an acrylic-based polymer, and a silicon-based polymer, but the embodiment is not limited thereto.

For example, the organic material portion including the organic non-piezoelectric material may include an adhesion promoter or an adhesion enhancer for adhesion between the epoxy resin and the inorganic material portion for high stiffness characteristics of the flexible vibration module 200. For example, the adhesion promoter may be a phosphate or the like. The organic material portion may be cured by at least one of a thermal curing process and a photo curing process. In the process of partially curing the organic material, the solvent-free epoxy may be used to avoid or prevent the thickness uniformity of the soft vibration module 200 from being degraded due to the shrinkage of the organic material portion caused by the volatilization of the solvent.

In addition, the organic material portion including the organic non-piezoelectric material may further include a reinforcing agent, for example, for damping characteristics of the flexible vibration module 200 other than high rigidity. For example, the reinforcing agent may be methylmethacrylate-butadiene-styrene (MBS) having a core-shell type, and the content thereof may be about 5 wt% to about 40 wt%. The reinforcing agent may be an elastomer having a core-shell type, and may have a high binding force to an epoxy resin such as an acrylic-based polymer. Accordingly, the reinforcing agent may enhance the impact resistance or damping characteristics of the flexible vibration module 200.

In the piezoelectric composite layer PCL, a first portion 210 containing an inorganic material and having piezoelectric properties and a second portion 220 containing an organic material and having flexibility may be alternately repeated and connected to each other. Therefore, the piezoelectric composite layer PCL may have a film type. Accordingly, the piezoelectric composite layer PCL may be bent based on the shape of the display panel 100 and may have a size corresponding to the display panel 100 or may have a size for realizing vibration characteristics or sound characteristics that may be individually set based on the vibration of the display panel 100. For example, the size of each first portion 210 and the size of each second portion 220 may be adjusted based on the piezoelectric properties and flexibility. For example, in a display device requiring more piezoelectric properties than flexibility, the size of each first portion 210 may be larger than the size of each second portion 220. As another example, in a display device requiring more flexibility than piezoelectric properties, the size of each second portion 220 may be larger than the size of each first portion 210. Therefore, the piezoelectric composite layer PCL can be adjusted based on the desired characteristics of the display device. Therefore, the piezoelectric composite layer PCL can be easily designed.

The first electrode layer 230 may be on a first surface (e.g., a front surface) of the piezoelectric composite layer PCL, and may be electrically connected to a first surface of each of the plurality of first portions 210. The first electrode layer 230 according to an embodiment may include a transparent conductive material, a semi-transparent (transmissive) conductive material, or an opaque conductive material. Examples of the transparent conductive material or the semi-transparent conductive material may include Indium Tin Oxide (ITO) or Indium Zinc Oxide (IZO), but the embodiment is not limited thereto. Examples of the opaque conductive material may include aluminum (Al), copper (Cu), gold (Au), silver (Ag), molybdenum (Mo), magnesium (Mg), and any alloy thereof, but the embodiment is not limited thereto.

The second electrode layer 240 may be on a second surface (e.g., a back surface) of the piezoelectric composite layer PCL opposite to the first surface, and may be electrically connected to a second surface of each of the plurality of first portions 210. The second electrode layer 240 according to an embodiment may include a transparent conductive material, a semi-transparent conductive material, or an opaque conductive material. For example, the second electrode layer 240 may include the same material as the first electrode layer 230.

The piezoelectric composite layer PCL may be polarized by a specific voltage applied to the first electrode layer 230 and the second electrode layer 240 in a specific temperature atmosphere or a temperature atmosphere that can be changed from a high temperature to a room temperature. The embodiments are not limited to these examples.

The flexible vibration module 200 according to an embodiment of the present disclosure may further include a first protective film 250 and a second protective film 260.

The first protective film 250 may be on the first electrode layer 230, and may protect the first electrode layer 230 or the first surface of the piezoelectric composite layer PCL. For example, the first protective film 250 may be a Polyimide (PI) film or a polyethylene terephthalate (PET) film, but the embodiment is not limited thereto.

The second protective film 260 may be positioned on the second electrode layer 240, and may protect the second electrode layer 240 or the second surface of the piezoelectric composite layer PCL. For example, the second protective film 260 may be a Polyimide (PI) film or a polyethylene terephthalate (PET) film, but the embodiment is not limited thereto.

Fig. 4 is a diagram illustrating a piezoelectric composite layer according to a first embodiment of the present disclosure.

Referring to fig. 4, the piezoelectric composite layer PCL according to the first embodiment of the present disclosure may include a plurality of first portions 210 and a plurality of second portions 220 that may be alternately disposed in the first direction X.

Each of the plurality of first portions 210 may have a first width d1 parallel to the first direction X and may have a length parallel to the second direction Y. Each of the plurality of second portions 220 may have a second width d2 that may be the same as the first width d1 and may have a length parallel to the second direction Y. For example, the first and second portions 210 and 220 may each have a line type or a bar type, each having the same size.

Therefore, in the piezoelectric composite layer PCL according to the first embodiment of the present disclosure, the first portions 210 and the second portions 220, each having the same size, may be alternately disposed (or connected) on the same plane. Accordingly, the piezoelectric composite layer PCL may have a single thin film type, may vibrate in a vertical direction by the first portion 210, and may be bent into a curved shape by the second portion 220. The piezoelectric composite layer PCL according to the first embodiment of the present disclosure may be enlarged to have a desired size or length, for example, by side coupling (or connection) of the first and second portions 210 and 220.

Fig. 5A is a view showing an example in which both ends of the piezoelectric composite layer of fig. 4 are folded upward. Fig. 5B is a view showing an example in which both ends of the piezoelectric composite layer of fig. 4 are folded downward.

Referring to fig. 5A and 5B, the piezoelectric composite layer PCL according to the first embodiment of the present disclosure may vibrate using an electric field based on a signal applied to each of the plurality of first portions 210 having the line pattern. Thus, both ends EP in the first length direction X may be folded in an upward direction + Z or may be folded in a downward direction-Z. For example, each of the plurality of second portions 220 filled or disposed between two adjacent first portions of the plurality of first portions 210 may have flexibility. Therefore, even when both ends EP of the piezoelectric composite layer PCL are bent in the upward direction + Z or the downward direction-Z, the inorganic material portion as each first portion 210 is not damaged or does not degrade the performance. Accordingly, the display device including the flexible vibration module 200 having the piezoelectric composite layer PCL according to the first embodiment of the present disclosure may be used as, for example, a curved display device that is curved at a certain radius of curvature, but the embodiment is not limited thereto. For example, the display device may be used as a rollable display device, a bendable display device, or a wearable display device that is rolled in a spiral form. The flexible display device may be an edge bending display device, a bezel bending display device, or an active bending display device, but the embodiment is not limited thereto.

Fig. 6 is a diagram illustrating a piezoelectric composite layer according to a second embodiment of the present disclosure.

Fig. 6 illustrates an embodiment implemented by modifying the first portion 210 of the piezoelectric composite layer PCL shown in fig. 4, and therefore, a repetitive description will be omitted below or will be briefly given.

Referring to fig. 6, in the piezoelectric composite layer PCL according to the second embodiment of the present disclosure, the plurality of first portions 210 and the plurality of second portions 220 may have different sizes.

Each of the plurality of first portions 210 may have a third width d3, and each of the plurality of second portions 220 may have a fourth width d4 different from the third width d 3. For example, the third width d3 of each first portion 210 may be greater than the fourth width d4 of each second portion 220. In addition, the third width d3 of each first portion 210 may be greater than the first width d1 of each first portion 210 shown in fig. 4.

In the piezoelectric composite layer PCL, when the third width d3, which is the width of the inorganic material portion of each first portion 210, is larger than the fourth width d4, which is the width of the organic material portion of each second portion 220, flexibility may be reduced. However, when the size of the inorganic material portion in which the vibration characteristics of the high-pitched vocal cord are relatively good is increased, the piezoelectric composite layer PCL may have improved high-pitched sound characteristics.

In the piezoelectric composite layer PCL according to the second embodiment of the present disclosure, the size of each of the first portions 210 may be larger than the size of each of the second portions 220. Therefore, the vibration characteristics of the high-pitched vocal cords can be increased. For example, the content (e.g., ratio) of the first portion 210 in the piezoelectric composite layer PCL shown in fig. 6 may be the same as the content (e.g., ratio) of the first portion 210 in the piezoelectric composite layer PCL shown in fig. 4. However, when the size of each first portion 210 is increased, the piezoelectric composite layer PCL shown in fig. 6 can further improve the vibration characteristics of the high-pitched vocal cords, as compared with the piezoelectric composite layer PCL shown in fig. 4.

Accordingly, when the size of each first portion 210 included in the piezoelectric composite layer PCL of the flexible vibration module 200 is increased (or enlarged), the display device including the piezoelectric composite layer PCL according to the second embodiment of the present disclosure may improve the sound characteristics of the high-pitched vocal cords generated by the vibration of the display panel 100 based on the vibration of the flexible vibration module 200. In addition, the display device including the piezoelectric composite layer PCL according to the second embodiment of the present disclosure may be used in a flexible display device that may be substantially similar to the display device including the flexible vibration module 200 shown in fig. 4.

Fig. 7 is a diagram illustrating a piezoelectric composite layer according to a third embodiment of the present disclosure.

Fig. 7 illustrates an embodiment implemented by modifying the first portion 210 and the second portion 220 of the piezoelectric composite layer PCL shown in fig. 4. Therefore, a repetitive description is omitted below or will be briefly given.

Referring to fig. 7, in the piezoelectric composite layer PCL according to the third embodiment of the present disclosure, the plurality of first portions 210 and the plurality of second portions 220 may have different sizes or may have the same size.

Each of the plurality of first portions 210 may have a third width d 3. Each of the plurality of second portions 220 may have a fifth width d5 that is different from the third width d 3. For example, the third width d3 of each first portion 210 may be greater than the first width d1 of each first portion 210 shown in fig. 4, and the fifth width d5 of each second portion 220 may be greater than the fourth width d4 of each second portion 220 shown in fig. 6.

In the piezoelectric composite layer PCL according to the third embodiment of the present disclosure, the size of each first portion 210 and the size of each second portion 220 may be increased. Therefore, the piezoelectric composite layer PCL shown in fig. 7 can further increase the vibration characteristics of the middle-pitched and/or the low-pitched sound bands, as compared with the piezoelectric composite layer PCL shown in each of fig. 4 and 6. For example, the content (e.g., ratio) of the first portion 210 in the piezoelectric composite layer PCL shown in fig. 7 may be higher than the content (e.g., ratio) of the first portion 210 in the piezoelectric composite layer PCL shown in fig. 4. In addition, the content (e.g., ratio) of the second portion 220 in the piezoelectric composite layer PCL shown in fig. 7 may be higher than the content (e.g., ratio) of the second portion 220 in the piezoelectric composite layer PCL shown in each of fig. 4 and 6. For example, the piezoelectric composite layer PCL shown in fig. 7 may have a size enlargement effect of each of the first portion 210 and the second portion 220. Accordingly, the vibration characteristics of the low-pitched vocal cords may be further increased due to the effect of the increased panel coverage of the flexible vibration module 200 with respect to the display panel 100 instead of the flexible vibration module 200.

Accordingly, the display device including the piezoelectric composite layer PCL according to the third embodiment of the present disclosure may increase the sound characteristics of the low-pitched sound band and the sound characteristics of the high-pitched sound band generated by the vibration of the display panel 100 due to the effect that the size of each of the first portion 210 and the second portion 220 included in the piezoelectric composite layer PCL is increased. Therefore, the flatness of the sound pressure can be improved due to the increase of the sound characteristic of the low-pitched vocal cords. In addition, a display device including the piezoelectric composite layer PCL according to the third embodiment of the present disclosure may be used in a flexible display device that may be substantially similar to the display device including the flexible vibration module 200 shown in fig. 4.

Fig. 8 is a diagram illustrating a piezoelectric composite layer according to a fourth embodiment of the present disclosure. Fig. 9 is a view illustrating an example in which both ends of the piezoelectric composite layer shown in fig. 8 are folded downward.

Fig. 8 illustrates an embodiment implemented by modifying the second portion 220 of the piezoelectric composite layer PCL shown in fig. 4. Therefore, a repetitive description is omitted below or will be briefly given.

Referring to fig. 8 and 9, in the piezoelectric composite layer PCL according to the fourth embodiment of the present disclosure, a size (e.g., a width) of each of the plurality of second portions 220 between the plurality of first portions 210 may be gradually decreased in a direction from a central portion CP to two edges or two peripheral edges (e.g., two end portions) EP of the piezoelectric composite layer PCL or the flexible vibration module 200.

The largest second portion 220 having the largest size among the plurality of second portions 220 may be located in a portion SCP where the highest stress may be concentrated when the flexible vibration module 200 vibrates in the vertical direction Z, and the smallest second portion 220 having the smallest size among the plurality of second portions 220 may be located in a portion SWP where a relatively low stress may occur when the flexible vibration module 200 vibrates in the vertical direction Z. For example, the largest second portion 220 having the largest size among the plurality of second portions 220 may be located in the central portion CP of the flexible vibration module 200, and the smallest second portion 220 having the smallest size among the plurality of second portions 220 may be located in each of the two edges or the circumference EP of the flexible vibration module 200. Accordingly, when the flexible vibration module 200 vibrates in the vertical direction Z, acoustic interference or resonance frequency overlapping, each occurring in the portion SCP where the highest stress is concentrated, may be reduced or minimized. Therefore, a drop (tapping) in sound pressure occurring in the low-pitched sound band can be reduced, thereby improving the flatness of the sound characteristics in the low-pitched sound band. Here, the flatness of the sound characteristic may be a level of deviation between the highest sound pressure and the lowest sound pressure.

The central portion CP of the flexible vibration module 200 may correspond to the second portion 220. The central portion CP of the flexible vibration module 200 may overlap with the second portion 220. For example, when the flexible vibration module 200 vibrates in the vertical direction Z, the flexibility of the central portion CP of the flexible vibration module 200 may increase. For example, when the central portion CP of the flexible vibration module 200 overlaps the first portion 210 or corresponds to the first portion 210, the first portion 210 may be damaged or degraded due to stress concentrated on the central portion CP of the flexible vibration module 200 when the flexible vibration module 200 vibrates in the vertical direction Z. Therefore, when the central portion CP of the flexible vibration module 200 overlaps the second portion 220 or corresponds to the second portion 220, the second portion 220 among the SCP portions where stress may be concentrated is not damaged or degraded when the flexible vibration module 200 vibrates in the vertical direction Z.

For example, each of the plurality of first portions 210 may have the same size (e.g., width).

As another example, each of the plurality of first portions 210 may have a different size (e.g., width). For example, the size (e.g., width) of each of the plurality of first portions 210 may gradually decrease or increase in a direction from the central portion CP of the piezoelectric composite layer PCL or the flexible vibration module 200 to both edges (e.g., both end portions) EP. For example, in the flexible vibration module 200, the sound pressure characteristic of sound may be enhanced and the sound reproduction band may be increased based on various natural vibration frequencies on the basis of the vibration of each of the plurality of first portions 210 having different sizes.

Accordingly, the display device including the piezoelectric composite layer PCL according to the fourth embodiment of the present disclosure may be used in a flexible display device that may be substantially similar to the display device including the flexible vibration module 200 shown in fig. 4.

Fig. 10 is a diagram illustrating a piezoelectric composite layer according to a fifth embodiment of the present disclosure.

Referring to fig. 10, the piezoelectric composite layer PCL according to the fifth embodiment of the present disclosure may include a plurality of first portions 210 that may each have a circular shape and may be spaced apart from each other, and a second portion 220 surrounding each of the plurality of first portions 210.

Each of the plurality of first portions 210 may have a circular plate shape. Each of the plurality of first portions 210 may include an inorganic material portion having a vibration characteristic as described above. Therefore, a repeated description of the material is omitted.

The second portion 220 may be disposed or filled between the plurality of first portions 210, and may surround a side surface of each of the plurality of first portions 210. The second portion 220 may include an organic material portion having flexibility as described above. Therefore, a repetitive description thereof will be omitted. The second portion 220 may provide flexibility between two adjacent first portions of the plurality of first portions 210. Accordingly, the piezoelectric composite layer PCL or the flexible vibration module 200 may have various shapes such as a two-dimensional (2D) shape or a three-dimensional (3D) shape based on the deformation occurring between two adjacent first portions of the plurality of first portions 210.

Each of the plurality of first portions 210 may have various shapes other than a circular plate shape. For example, each of the plurality of first portions 210 may have an oval shape, a polygonal shape, or an annular shape, but the embodiment is not limited thereto. The oval shape may include an ellipse, an egg shape, a rounded rectangle, or other non-circular curved shape that varies in width and height.

Each of the plurality of first portions 210 may have a dot shape including, for example, a fine (or micro) circle, a fine oval, a fine polygon, or a fine ring. The display device including the flexible vibration module 200 having the plurality of first portions 210 may have various shapes based on the flexibility of the second portion 220 located between two adjacent first portions among the plurality of first portions 210. For example, the shape of the display panel of the display device including the flexible vibration module 200 shown in each of fig. 4 to 9 may be a 2D shape based on the first portion 210 (e.g., inorganic material portion) having a line shape, and the 2D shape may be a concave shape or a convex shape. Accordingly, the display panel of the display device including the flexible vibration module 200 shown in fig. 10 may have various shapes such as a 3D shape and a 2D shape based on the first portion 210 (e.g., inorganic material portion) having a dotted shape. Accordingly, the flexible vibration module 200 including the piezoelectric composite layer PCL according to the fifth embodiment of the present disclosure may be enhanced in a degree of freedom in design based on the shape of the display device, and may be applied to a flexible display device whose shape can be changed into various shapes such as a 2D shape or a 3D shape.

Fig. 11 is a diagram illustrating a piezoelectric composite layer according to a sixth embodiment of the present disclosure. Fig. 12 is a view illustrating an embodiment of the piezoelectric composite layer shown in fig. 11.

Referring to fig. 11, the piezoelectric composite layer PCL according to the sixth embodiment of the present disclosure may include a plurality of first portions 210 each of which may have a triangular shape and may be spaced apart from each other, and a second portion 220 surrounding each of the plurality of first portions 210.

Each of the plurality of first portions 210 may have a triangular shape. For example, each of the plurality of first portions 210 may have a triangular plate shape. Each of the plurality of first portions 210 may include an inorganic material portion having a vibration characteristic as described above. Therefore, a repetitive description thereof will be omitted.

For example, four adjacent first portions 210 of the plurality of first portions 210 may be adjacent to each other to form a quadrangle or quadrilateral shape (e.g., a square shape). The apexes of four adjacent first portions 210 forming a quadrangle shape may be adjacent to each other in the central portion of the quadrangle shape. As another example, as shown in fig. 12, six adjacent first portions 210 of the plurality of first portions 210 may be adjacent to each other to form a hexagonal shape (e.g., a regular hexagonal shape). The vertices of six adjacent first portions 210 forming the hexagonal shape may be adjacent to each other in the central portion of the hexagonal shape. Accordingly, 2N (where N is a natural number equal to or greater than 2) adjacent first portions 210 among the plurality of first portions 210 may be disposed adjacent to each other to form a 2N corner shape.

The second portion 220 may be disposed or filled between the plurality of first portions 210, and may surround a side surface of each of the plurality of first portions 210. The second portion 220 may include an organic material portion having flexibility as described above. Therefore, a repetitive description thereof will be omitted. The second portion 220 may provide flexibility between two adjacent first portions of the plurality of first portions 210. Accordingly, the piezoelectric composite layer PCL or the flexible vibration module 200 may have various shapes such as a 3D shape and a 2D shape based on deformation occurring between two adjacent first portions of the plurality of first portions 210.

Accordingly, in the display device including the flexible vibration module 200 having the piezoelectric composite layer PCL according to the sixth embodiment of the present disclosure, the display panel may be changed based on various 3D shape changes of the flexible vibration module 200. In addition, the plurality of first portions 220 having the triangular shape may have fine patterns (e.g., micro patterns) corresponding to various shapes, and the display panel of the display device including the flexible vibration module 200 having the first portions 210 may have various shapes based on the flexibility of the second portion 220 located between two adjacent first portions among the plurality of first portions 210. In addition, a display device including the piezoelectric composite layer PCL according to the sixth embodiment of the present disclosure may be used in a flexible display device substantially similar to the display device including the flexible vibration module 200 shown in fig. 4.

Fig. 13 is a diagram illustrating a flexible vibration module according to another embodiment of the present disclosure.

Referring to fig. 13, the flexible vibration module 200 according to another embodiment of the present disclosure may include a first piezoelectric composite layer PCL1, a first electrode layer 230, a second electrode layer 240, an insulating layer 270, a second piezoelectric composite layer PCL2, a third electrode layer 231, and a fourth electrode layer 241.

The first piezoelectric composite layer PCL1 may include a plurality of first portions 210 and a plurality of second portions 220 each disposed between the plurality of first portions 210.

Each of the plurality of first portions 210 may include an inorganic material or a piezoelectric material that may each vibrate according to an electric field-based piezoelectric effect (e.g., piezoelectric characteristics), and may be substantially similar to the first portion shown in each of fig. 3 to 7. Therefore, a repetitive description thereof is omitted.

Each of the plurality of second portions 220 may include an organic material portion having flexibility, and may be substantially similar to the second portion shown in each of fig. 3 to 7. Therefore, a repetitive description thereof is omitted.

The first electrode layer 230 may be located on a first surface (e.g., a front surface) of the first piezoelectric composite layer PCL1, and may be electrically connected to a first surface of each of the plurality of first portions 210. The first electrode layer 230 according to an embodiment may include a transparent conductive material, a semi-transparent conductive material, or an opaque conductive material.

The second electrode layer 240 may be on a second surface (e.g., a back surface) of the first piezoelectric composite layer PCL1 opposite to the first surface, and may be electrically connected to a second surface of each of the plurality of first portions 210. The second electrode layer 240 according to an embodiment may include a transparent conductive material, a semi-transparent conductive material, or an opaque conductive material. For example, the second electrode layer 240 may include the same material as the first electrode layer 230.

The insulating layer 270 may be on the first electrode layer 230. Insulating layer 270 may comprise an electrically insulating material that is adhesive and compressible and recoverable. For example, the insulating layer 270 may include at least one of an epoxy-based polymer, an acrylic-based polymer, and a silicon-based polymer, but the embodiment is not limited thereto.

The second piezoelectric composite layer PCL2 may be on the insulating layer 270. The second piezoelectric composite layer PCL2 may include a plurality of first portions 211 and a plurality of second portions 221 each disposed between the plurality of first portions 211.

Each of the plurality of first portions 211 of the second piezoelectric composite layer PCL2 may include an inorganic material or a piezoelectric material that may each vibrate according to an electric field-based piezoelectric effect (e.g., piezoelectric characteristics), and may be the same as the plurality of first portions 210 of the first piezoelectric composite layer PCL 1.

For example, the first portions 211 of the second piezoelectric composite layers PCL2 may overlap the first portions 210 of the first piezoelectric composite layers PCL1, respectively. For example, the first portions 211 of the second piezoelectric composite layer PCL2 may respectively correspond to the first portions 210 of the first piezoelectric composite layer PCL 1. For example, in the flexible vibration module 200 according to another embodiment of the present disclosure, the first portions 211 of the second piezoelectric composite layer PCL2 may overlap the first portions 210 of the first piezoelectric composite layer PCL1, respectively, in a vertical direction. Therefore, an expansion force (e.g., a tensile force) and a contraction force (e.g., a compressive force), each based on a bimorph structure, may be increased, thereby enhancing the sound pressure characteristic.

For example, the first portions 211 of the second piezoelectric composite layers PCL2 may overlap the second portions 220 of the first piezoelectric composite layers PCL1, respectively. For example, the first portions 211 of the second piezoelectric composite layer PCL2 may respectively correspond to the second portions 220 of the first piezoelectric composite layer PCL 1. For example, in the flexible vibration module 200 according to another embodiment of the present disclosure, the first portion 211 of the second piezoelectric composite layer PCL2 and the first portion 210 of the first piezoelectric composite layer PCL1 may be alternately disposed in the vertical direction. Accordingly, the first portions 210 and 211 having piezoelectric properties may be juxtaposed and may not be spaced apart from each other. Accordingly, the entire area of the flexible vibration module 200 according to another embodiment of the present disclosure may vibrate, and a sound reproduction band based on the use of a wide area may be increased.

Each of the plurality of second portions 221 of the second piezoelectric composite layer PCL2 may include an organic material portion having flexibility, and may be the same as the second portion 220 of the first piezoelectric composite layer PCL 1.

The third electrode layer 231 may be located on a first surface (e.g., a front surface) of the second piezoelectric composite layer PCL2, and may be electrically connected to the first surface of each of the plurality of first portions 211 of the second piezoelectric composite layer PCL 2. The third electrode layer 231 according to an embodiment may include a transparent conductive material, a semi-transparent conductive material, or an opaque conductive material.

The fourth electrode layer 241 may be located between the insulating layer 270 and the second piezoelectric composite layer PCL2, and may be electrically connected to a second surface (e.g., a rear surface) of each of the plurality of first portions 211 of the second piezoelectric composite layer PCL2, which is opposite to the first surface. The fourth electrode layer 241 according to an embodiment may include a transparent conductive material, a semi-transparent conductive material, or an opaque conductive material. For example, the fourth electrode layer 241 may include the same material as the first electrode layer 230.

The first electrode layer 230 and the second electrode layer 240 may receive a first electrical signal for vibrating the first piezoelectric composite layer PCL 1. In addition, the third electrode layer 231 and the fourth electrode layer 241 may receive a second electrical signal for vibrating the second piezoelectric composite layer PCL 2. For example, the first electrical signal and the second electrical signal may have the same phase or opposite phases.

As another example, in the flexible vibration module 200 according to the present embodiment, the insulating layer 270 and the fourth electrode layer 241 may be omitted. For example, the first electrode layer 230 may be used as a common electrode (e.g., a common electrode) of the first piezoelectric composite layer PCL1 and the second piezoelectric composite layer PCL 2. For example, the polarization direction of each first portion 210 located in the first piezoelectric composite layer PCL1 may be a direction opposite to the polarization direction of each first portion 211 located in the second piezoelectric composite layer PCL 2. In addition, the first electrode layer 230 may be electrically connected to the first surface of each first portion 210 of the first piezoelectric composite layer PCL1, and may be electrically connected to the second surface of each first portion 211 of the second piezoelectric composite layer PCL 2. In addition, the second electrode layer 240 and the third electrode layer 231 may be electrically connected to each other or may receive the same electrical signal.

The flexible vibration module 200 according to another embodiment of the present disclosure may further include a first protective film 250 and a second protective film 260.

The first protective film 250 may be on the third electrode layer 231 and may protect the first surface of the third electrode layer 231 or the second piezoelectric composite layer PCL 2. For example, the first protective film 250 may be a Polyimide (PI) film or a polyethylene terephthalate (PET) film, but the embodiment is not limited thereto.

The second protective film 260 may be positioned on the second electrode layer 240, and may protect the second electrode layer 240 or the second surface of the first piezoelectric composite layer PCL 1. For example, the second protective film 260 may be a Polyimide (PI) film or a polyethylene terephthalate (PET) film, but the embodiment is not limited thereto.

The flexible vibration module 200 according to another embodiment of the present disclosure may have a bimorph shape based on the first and second piezoelectric composite layers PCL1 and PCL 2. Accordingly, the flexible vibration module 200 may sufficiently vibrate the display panel in a vertical (e.g., front-to-back) direction, thereby enhancing a sound pressure characteristic based on the vibration of the display panel.

Fig. 14 is a perspective view of a display device according to another embodiment of the present disclosure. Fig. 15 is a diagram illustrating a first vibration module and a second vibration module located on a rear surface of the display panel shown in fig. 14.

Fig. 14 and 15 illustrate an embodiment implemented by modifying the flexible vibration module of the display device shown in fig. 1. Therefore, hereinafter, a repetitive description of elements other than the first vibration module and the second vibration module will be omitted or will be briefly given.

Referring to fig. 14 and 15, a flexible vibration module of a display device according to another embodiment of the present disclosure may include a first vibration module 200-1 and a second vibration module 200-2 each disposed on a rear surface of a display panel 100.

The rear surface (e.g., the rear surface) of the display panel 100 may include a first area a1 and a second area a 2. For example, a rear surface (e.g., a rear surface) of the display panel 100 may be divided into a first area a1 and a second area a 2. For example, in the rear surface of the display panel 100, the first area a1 may be a left area, and the second area a2 may be a right area. The terms "left" and "right" are used herein for convenience of description and are interchangeable, as will be understood by one of ordinary skill in the art. The first and second regions a1 and a2 may be laterally symmetrical in the first direction X with respect to a center line CL of the display panel 100.

The first vibration module 200-1 may be located in the first area a1 of the display panel 100. The first vibration module 200-1 may vibrate the first region a1 of the display panel 100 to generate the first panel vibration sound PVS1 or the first tactile feedback in the first region a1 of the display panel 100. For example, the first panel vibration sound PVS1 may be a left sound.

The first vibration module 200-1 may be near a central portion or an edge (e.g., a peripheral edge) of the display panel 100 in the first area a1 of the display panel 100 with respect to the first direction X. For example, the first vibration module 200-1 may be adjacent to the first partition member 610 or the third partition member 630. The first vibration module 200-1 may have a size equal to or greater than half of the first area a1, but the embodiment is not limited thereto. For example, the size may be adjusted based on the desired sound characteristics of the display device.

The second vibration module 200-2 may be located in the second area a2 of the display panel 100. The second vibration module 200-2 may vibrate the second region a2 of the display panel 100 to generate the second panel vibration sound PVS2 or the second tactile feedback in the second region a2 of the display panel 100. For example, the second panel vibration sound PVS2 may be a right sound.

The second vibration module 200-2 may be near a central portion or an edge (e.g., a peripheral edge) of the display panel 100 in the second area a2 of the display panel 100 with respect to the first direction X. For example, the second vibration module 200-2 may be adjacent to the second partition member 620 or the third partition member 630. The second vibration module 200-2 may have a size equal to or greater than half of the second area a2, but the embodiment is not limited thereto. For example, the size may be adjusted based on the desired sound characteristics of the display device.

Each of the first and second vibration modules 200-1 and 200-2 according to an embodiment may include a piezoelectric composite layer PCL, which may include a plurality of first portions 210 having a linear shape and spaced apart from each other and a plurality of second portions 220 each disposed between the plurality of first portions 210. This may be substantially similar to the flexible vibration module 200 shown in fig. 3-9. Therefore, the repetitive description is omitted. For example, each of the first and second vibration modules 200-1 and 200-2 may be configured as one of the flexible vibration modules 200 according to any one of the first to fourth embodiments of the present disclosure.

The display apparatus according to the embodiment of the present disclosure may further include a partition 600 for dividing the first and second areas a1 and a2 of the display panel 100.

The spacer 600 may be an air gap or a space that generates sound when the display panel 100 is vibrated by the first and second vibration modules 200-1 and 200-2. The air gap or space in which sound is generated or transmitted may be referred to as a partition. The partition 600 may separate sounds or sound channels, and may prevent or reduce generation of sounds that are unclear and are caused by sound interference. The partition 600 may be referred to as a "baffle" or a "baffle", but the term is not limited thereto.

The partition 600 according to one embodiment may include a first partition member 610 and a second partition member 620 between the first vibration module 200-1 and the second vibration module 200-2.

The first and second partition members 610 and 620 may be located between the display panel 100 and the rear structure 300 corresponding to the display panel 100. The first and second partition members 610 and 620 may separate the first and second panel vibration sounds PVS1 and PVS2 generated by the first and second vibration modules 200-1 and 200-2, respectively. For example, the first and second partition members 610 and 620 may reduce, block, or prevent the transmission of the vibration generated by the first vibration module 200-1 in the first region a1 of the display panel 100 to the second region a2 of the display panel 100, or may reduce, block, or prevent the transmission of the vibration generated by the second vibration module 200-2 in the second region a2 of the display panel 100 to the first region a1 of the display panel 100. Accordingly, the first and second partition members 610 and 620 may attenuate or absorb vibration of the display panel 100 at the center of the display panel 100. Accordingly, the first and second partition members 610 and 620 may reduce, block, or prevent the transmission of the sound of the first region a1 to the second region a2, or may reduce, block, or prevent the transmission of the sound of the second region a2 to the first region a 1. Accordingly, the first and second partition members 610 and 620 may separate the left and right sounds to further enhance the sound output characteristics of the display apparatus. Accordingly, the display apparatus according to the present embodiment may separate left and right sounds by using the first and second partition members 610 and 620 to output two-channel stereo sound to a front region in front of the display panel 100.

For example, the separator 600 may include polyurethane, polyolefin, and/or the like, but the embodiment is not limited thereto. As another example, the separator 600 may include a double-sided adhesive tape or a single-sided adhesive tape. For example, the partition 600 may include a material having an elastic force that can be compressed to a certain degree.

As another example, one of the first and second partition members 610 and 620 may be omitted. For example, when the second partition member 620 of the first and second partition members 610 and 620 is omitted, the first partition member 610 may be located between the display panel 100 and the rear structure 300 to correspond to the rear center line CL of the display panel 100. For example, even when one of the first and second partition members 610 and 620 is located between the first and second vibration modules 200-1 and 200-2, the left and right sounds may be separated from each other.

Accordingly, the first and second partition members 610 and 620 may separate left and right sounds to further enhance sound output characteristics of the display apparatus. The display apparatus including the first or second partition member 610 or 620 may separate left and right sounds by using the first or second partition member 610 or 620 to output two-channel stereo sound to a front region in front of the display panel 100.

The partition 600 according to one embodiment may further include a third partition member 630 between the display panel 100 and the rear structure 300.

The third partition member 630 may be disposed along a space between a rear edge (e.g., a rear circumferential edge) of the display panel 100 and a front edge (e.g., a front circumferential edge) of the rear structure 300 to entirely surround the first and second vibration modules 200-1 and 200-2. The third partition member 630 may be referred to as an "edge partition", "sound blocking member", "edge barrier", or "baffle", but the term is not limited thereto. For example, the third partition member 630 may be adjacent to or in contact with the panel fixing member 400 shown in fig. 2, and may be surrounded by the panel fixing member 400. As another example, the third partition member 630 may be integrated with the panel fixing member 400.

The third partition member 630 may provide the first to third air gaps AG1 to AG3 between the display panel 100 and the rear structure 300 together with the first and second partition members 610 and 620. For example, each of the first to third air gaps AG1 to AG3 may be referred to as a "vibration space", a "sound pressure space", an "acoustic box", an "acoustic part", a "resonance box", or a "resonance part", but the term is not limited thereto.

The first air gap AG1 may be located in the first area a1 of the display panel 100, and may be surrounded by the first and third partition members 610 and 630 in the first area a1 of the display panel 100.

The second air gap AG2 may be located in the second region a2 of the display panel 100, and may be surrounded by the second and third partition members 620 and 630 in the second region a2 of the display panel 100.

The third air gap AG3 may be located in a central region (e.g., a third region) of the display panel 100 surrounded by the first and second partition members 610 and 620 and the third partition member 630. For example, the third air gap AG3 may be located between the second air gap AG2 and the first air gap AG1, including the rear centerline CL of the display panel 100. The third air gap AG3 may be referred to as an "acoustic separation space", "acoustic blocking space", or "acoustic interference prevention space", but the term is not limited thereto. The third gap AG3 may spatially separate the first gap AG1 from the second gap AG 2. Accordingly, the third air gap AG3 may reduce or prevent a resonance phenomenon or a disturbance phenomenon that may occur in each of the first and second air gaps AG1 and 2 and may correspond to a specific frequency band.

The first vibration module 200-1 may be surrounded by the first and third partition members 610 and 630 providing the first air gap AG 1. The second vibration module 200-2 may be surrounded by the second and third partition members 620 and 630 providing the second air gap AG 2.

When one of the first and second partition members 610 and 620 is omitted, the third air gap AG3 may be omitted.

Accordingly, the third partition member 630 may surround the region between the display panel 100 and the rear structure 300, and may separately surround each of the first and second vibration modules 200-1 and 200-2 together with the first and second partition members 610 and 620 to ensure a vibration space of each of the first and second vibration modules 200-1 and 200-2. Accordingly, the third partition member 630 may enhance the sound pressure characteristics of the left and right sounds and may reduce or prevent the sound or the sound pressure from leaking to the outside through the side surface between the display panel 100 and the rear structure 300, thereby further enhancing the sound output characteristics of the display apparatus.

The partition 600 according to one embodiment may further include a fourth partition member 640 surrounding the first vibration module 200-1 and a fifth partition member 650 surrounding the second vibration module 200-2.

The fourth partition member 640 may be located between the display panel 100 and the rear structure 300 to correspond to the first air gap AG1, and may individually (e.g., independently) surround the first vibration module 200-1. The fourth partition member 640 according to an embodiment may have a circular shape surrounding the first vibration module 200-1, but the embodiment is not limited thereto. For example, the fourth partition member 640 may have the same or different shape as the overall shape of the first vibration module 200-1. For example, when the first vibration module 200-1 has a rectangular shape, the fourth partition member 640 may have a rectangular shape having a size relatively larger than that of the first vibration module 200-1.

The fourth partition member 640 may limit (or define) a vibration region (e.g., a vibration area) of the display panel 100 based on the first vibration module 200-1. For example, in the first region a1 of the display panel 100, as the size of the fourth partition member 640 increases, the vibration region of the first region a1 may increase. Therefore, the low-pitched sound band characteristic of the left sound can be enhanced. On the other hand, in the first region a1 of the display panel 100, as the size of the fourth partition member 640 decreases, the vibration region of the first region a1 may decrease. Therefore, the high-pitched sound band characteristic of the left sound can be enhanced. Accordingly, the size of the fourth partition member 640 may be adjusted according to desired characteristics of the vocal cords based on the vibration of the display panel 100.

The fifth partition member 650 may be located between the display panel 100 and the rear structure 300 to correspond to the second air gap AG2, and may individually (e.g., independently) surround the second vibration module 200-2. In order to make the left sound symmetrical to the right sound, the fifth partition member 650 may have the same shape as the fourth partition member 640 and a structure symmetrical to the fourth partition member 640 with respect to the rear center line CL of the display panel 100. Therefore, the description related thereto is omitted.

The fifth partition member 650 may limit (or define) a vibration area (e.g., a vibration area) of the display panel 100 based on the second vibration module 200-2. For example, in the second region a2 of the display panel 100, as the size of the fifth partition member 650 increases, the vibration area of the second region a2 may increase. Therefore, the low-pitched sound band characteristic of the right sound can be enhanced. On the other hand, in the second region a2 of the display panel 100, as the size of the fifth partition member 650 decreases, the vibration region of the second region a2 may decrease. Therefore, the high-pitched sound band characteristic of the right sound can be enhanced. Accordingly, the size of the fifth partition member 650 may be adjusted according to desired characteristics of the vocal cords based on the vibration of the display panel 100.

The fourth and fifth partition members 640 and 650 may limit a vibration area (e.g., a vibration area) of each of the first and second vibration modules 200-1 and 200-2. Accordingly, the fourth and fifth partition members 640 and 650 may enhance lateral symmetry of the left and right sounds each generated based on the vibration of the display panel 100, and may optimize sound pressure characteristics and sound reproduction bands of the left and right sounds, respectively. As another example, when the fourth partition member 640 and the fifth partition member 650 are provided, the third partition member 630 may be omitted. As another example, when the fourth partition member 640 and the fifth partition member 650 are provided, one of the first to third partition members 610 to 630 may be omitted.

Therefore, when the display device according to the present embodiment includes the partition 600, the sound pressure characteristics and the sound reproduction band of each of the left and right sounds can be improved or optimized. For example, the display apparatus according to the present embodiment may include at least one of the first and second partition members 610 and 620. As another example, the display apparatus according to the present embodiment may include one of the first and second partition members 610 and 620 and the third partition member 630. As another example, the display apparatus according to the present embodiment may include a third partition member 630, a fourth partition member 640, and a fifth partition member 650. As another example, the display apparatus according to the present embodiment may include first to fifth partition members 610 to 650.

The display apparatus according to another embodiment of the present disclosure may output left and right sounds to the front region FD in front of the display panel 100 through the first and second vibration modules 200-1 and 200-2 to provide stereo sound to a user. In addition, the display apparatus according to another embodiment of the present disclosure may separate left and right sounds by using the partition 600 to output two-channel stereo sound to the forward region FD in front of the display panel 100.

Fig. 16 is a diagram illustrating a first modified embodiment of each of the first and second vibration modules shown in fig. 15.

Referring to fig. 16, each of the first and second vibration modules 200-1 and 200-2 according to the first modified embodiment may include a piezoelectric composite layer PCL, which may include a plurality of first portions 210 spaced apart from each other and a plurality of second portions 220 each disposed between the plurality of first portions 210.

Each of the plurality of first portions 210 may include an inorganic material portion having a vibration characteristic as described above. Therefore, a repeated description of the material is omitted.

The plurality of first portions 210 according to the embodiment may be disposed apart from each other in the first direction X and the second direction Y to each have a quadrangular or quadrangular shape (e.g., a square shape). The plurality of first portions 210 may be disposed adjacent to each other to form a quadrangular or quadrangular shape (e.g., a square shape).

According to another embodiment, the plurality of first portions 210 may be disposed apart from each other in the first direction X and the second direction Y to each have a circular shape or an oval or annular shape as shown in the example of fig. 10.

Each of the plurality of first portions 210 according to another example may include 2N triangular patterns as shown in fig. 11 (where N is a natural number equal to or greater than 2). The 2N triangular patterns may be adjacent to each other to form a 2N corner shape. Vertices of 2N triangular patterns forming the 2N horn shape may be adjacent to each other in the central portion having the 2N horn shape.

The second portions 220 may each be disposed or filled between two adjacent first portions of the plurality of first portions 210. For example, each of the second portions 220 may have a "+" shape disposed between four first portions 210 forming a quadrangular or quadrilateral shape (e.g., a square shape). The second portions 220 may each include an organic material portion having flexibility as described above. Therefore, a repeated description of the material is omitted. Each of the second portions 220 may provide flexibility between two adjacent first portions of the plurality of first portions 210. Accordingly, the piezoelectric composite layer PCL or each of the first and second vibration modules 200-1 and 200-2 may have various shapes based on deformation occurring between two adjacent first portions of the plurality of first portions 210.

The first and second vibration modules 200-1 and 200-2 may each further include a first electrode layer, which may be on the first surface of the piezoelectric composite layer PCL and may be electrically connected to the first surface of each of the plurality of first portions 210. The first and second vibration modules 200-1 and 200-2 may each further include a second electrode layer, which may be on a second surface of the piezoelectric composite layer PCL opposite to the first surface, and may be electrically connected to a second surface of each of the plurality of first portions 210. In addition, each of the first and second vibration modules 200-1 and 200-2 may further include a first protective film covering the first electrode layer and a second protective film covering the second electrode layer. The first electrode layer, the second electrode layer, the first protective film, and the second protective film are as described above. Therefore, a repetitive description thereof will be omitted.

The display apparatus according to the present embodiment may further include a spacer 600 between the display panel 100 and the rear structure 300. For example, the divider 600 may be substantially similar to the divider 600 described above with reference to fig. 15. Therefore, a repetitive description thereof will be omitted.

The display apparatus according to the present embodiment may output left and right sounds through the first and second vibration modules 200-1 and 200-2 to provide stereo sound to a user. In addition, the display apparatus according to the present embodiment may separate left and right sounds by using the partition 600 to output two-channel stereo sound.

Fig. 17 is a diagram illustrating a second modified embodiment of each of the first and second vibration modules shown in fig. 15.

Referring to fig. 17, each of the first and second vibration modules 200-1 and 200-2 according to the second modified embodiment may include a piezoelectric composite layer PCL, which may include a plurality of first portions 210 each of which may have a triangular shape and be spaced apart from each other, and a plurality of second portions 220 each disposed between the plurality of first portions 210.

Each of the plurality of first portions 210 may include an inorganic material portion having a vibration characteristic as described above. Therefore, a repeated description of the material is omitted.

The plurality of first portions 210 according to the embodiment may be disposed to be spaced apart from each other to form a hexagonal shape (e.g., a regular hexagonal shape). The vertices of adjacent first portions 210 forming the hexagonal shape may be adjacent to each other in a central portion of the hexagonal shape.

The plurality of first portions 210 according to another example may be adjacent to each other to form a2 i-angle shape, where i is a natural number equal to or greater than 4. The apexes of the adjacent first portions 210 forming the 2 i-cornered shape may be adjacent to each other in the central portion of the 2 i-cornered shape.

The second portions 220 may each be disposed or filled between two adjacent first portions of the plurality of first portions 210. For example, each of the second portions 220 may have an "x" shape located between six first portions 210 forming a hexagonal shape (e.g., a regular hexagonal shape). The second portions 220 may each include an organic material portion having flexibility as described above. Therefore, a repetitive description thereof will be omitted. Each of the second portions 220 may provide flexibility between two adjacent first portions of the plurality of first portions 210. Accordingly, the piezoelectric composite layer PCL or each of the first and second vibration modules 200-1 and 200-2 may have various shapes based on deformation occurring between two adjacent first portions of the plurality of first portions 210.

The plurality of first portions 210 having a triangular shape may be disposed adjacent to each other to have an angular shape of 2j, where j is a natural number equal to or greater than 3. Therefore, the piezoelectric composite layer PCL of each of the first vibration module 200-1 and the second vibration module 200-2 can be implemented as a vibration source (e.g., a vibration body) that can be substantially circular, thereby enhancing vibration characteristics.

Each of the first and second vibration modules 200-1 and 200-2 may further include a first electrode layer, which may be located on the first surface of the piezoelectric composite layer PCL and may be electrically connected to the first surface of each of the plurality of first portions 210. Each of the first and second vibration modules 200-1 and 200-2 may further include a second electrode layer that may be located on a second surface of the piezoelectric composite layer PCL opposite to the first surface and may be electrically connected to a second surface of each of the plurality of first portions 210. In addition, each of the first and second vibration modules 200-1 and 200-2 may further include a first protective film covering the first electrode layer and a second protective film covering the second electrode layer. The first electrode layer, the second electrode layer, the first protective film, and the second protective film are as described above. Therefore, a repetitive description thereof will be omitted.

The display apparatus according to the present embodiment may further include a spacer 600 between the display panel 100 and the rear structure 300. For example, the divider 600 may be substantially similar to the divider 600 described above with reference to fig. 15. Therefore, a repetitive description thereof is omitted. The fourth and fifth partition members 640 and 650 shown in fig. 17 may each have a hexagonal shape identical to that of each of the first and second vibration modules 200-1 and 200-2.

The display apparatus according to the present embodiment may output left and right sounds through the first and second vibration modules 200-1 and 200-2 to provide stereo sound to a user. In addition, the display device according to the present embodiment may output sound through the first and second vibration modules 200-1 and 200-2, which may be substantially circular, thereby enhancing sound characteristics. In addition, the display apparatus according to the present embodiment may separate left and right sounds by using the partition 600 to output two-channel stereo sound.

Fig. 18 is a diagram illustrating an example of each of the first to fourth vibration modules located on the rear surface of the display panel shown in fig. 14.

Fig. 18 illustrates an embodiment implemented by modifying the flexible vibration module shown in fig. 14. Therefore, hereinafter, a repetitive description of elements other than the first to fourth vibration modules will be omitted or will be briefly given.

Referring to fig. 18 in conjunction with fig. 14, the flexible vibration module of the display device according to another embodiment of the present disclosure may include first to fourth vibration modules 200-1 to 200-4 on the rear surface of the display panel 100.

The rear surface (e.g., the rear surface) of the display panel 100 may include a first area a1 and a second area a 2. For example, a rear surface (e.g., a rear surface) of the display panel 100 may be divided into a first area a1 and a second area a 2. For example, in the rear surface of the display panel 100, the first area a1 may be a left area, and the second area a2 may be a right area. The first and second regions a1 and a2 may be laterally symmetrical in the first direction X with respect to a center line CL of the display panel 100.

The first and third vibration modules 200-1 and 200-3 may be alternately or diagonally disposed in the first area a1 of the display panel 100. Accordingly, the first and third vibration modules 200-1 and 200-3 may increase the vibration area of the first region a1 of the display panel 100. For example, a third vibration module 200-3 may be provided in addition to the first vibration module 200-1. Therefore, the first panel vibration sound PVS1 can be further enhanced. Each of the first and third vibration modules 200-1 and 200-3 may vibrate the first area a1 of the display panel 100 to generate the first panel vibration sound PVS1 or the first tactile feedback in the first area a1 of the display panel 100. For example, the first panel vibration sound PVS1 may be a left sound. For example, the vibration area of the first region a1 of the display panel 100 may be increased based on the diagonal arrangement structure of the first and third vibration modules 200-1 and 200-3. Therefore, the low-pitched sound band characteristic of the left sound can be enhanced.

The first and third vibration modules 200-1 and 200-3 may be parallel in the first direction X or the second direction Y in the first area a1 of the display panel 100. For example, the vibration area of the first region a1 of the display panel 100 may be increased based on the parallel arrangement structure of the first and third vibration modules 200-1 and 200-3, thereby enhancing the low-pitched sound band characteristic of the left sound. The diagonal arrangement structure of the first and third vibration modules 200-1 and 200-3 may further increase the vibration area of the first region a1 of the display panel 100, compared to the parallel arrangement structure of the first and third vibration modules 200-1 and 200-3, thereby enhancing the low-pitched sound band characteristic of the left sound. The diagonal arrangement structure of the first and third vibration modules 200-1 and 200-3 may have an effect that the vibration modules may be arranged in a2 × 2 structure in the first area a1 of the display panel 100. Accordingly, the number of vibration modules for vibrating the first region a1 of the display panel 100 may be reduced by half.

The second and fourth vibration modules 200-2 and 200-4 may be alternately or diagonally disposed in the second area a2 of the display panel 100. Accordingly, the second and fourth vibration modules 200-2 and 200-4 may increase the vibration area of the second region a2 of the display panel 100. For example, a fourth vibration module 200-4 may be provided in addition to the second vibration module 200-2. Therefore, the second panel vibration sound PVS2 can be further enhanced. Each of the second and fourth vibration modules 200-2 and 200-4 may vibrate the second area a2 of the display panel 100 to generate the second panel vibration sound PVS2 or the second tactile feedback in the second area a2 of the display panel 100. For example, the second panel vibration sound PVS2 may be a right sound. For example, the vibration area of the second region a2 of the display panel 100 may be increased based on the diagonal arrangement structure of the second and fourth vibration modules 200-2 and 200-4. Therefore, the low-pitched sound band characteristic of the right sound can be enhanced.

The second and fourth vibration modules 200-2 and 200-4 may be parallel in the first direction X or the second direction Y in the second area a2 of the display panel 100. For example, the vibration area of the second region a2 of the display panel 100 may be increased based on the parallel arrangement structure of the second and fourth vibration modules 200-2 and 200-4, thereby enhancing the low-pitched sound band characteristic of the right sound. The diagonal arrangement structure of the second and fourth vibration modules 200-2 and 200-4 may further increase the vibration area of the second region a2 of the display panel 100, compared to the parallel arrangement structure of the second and fourth vibration modules 200-2 and 200-4, thereby enhancing the low-pitched sound band characteristic of the right sound. The diagonal arrangement structure of the second and fourth vibration modules 200-2 and 200-4 may have an effect that the vibration modules may be arranged in a2 × 2 structure in the second area a2 of the display panel 100. Accordingly, the number of vibration modules for vibrating the second region a2 of the display panel 100 may be reduced by half.

The first vibration module 200-1 may be located in the first area a1 of the display panel 100. As another example, the first vibration module 200-1 may be near an edge or a periphery of the display panel 100 in the first area a1 of the display panel 100 with respect to the first direction X. For example, the first vibration module 200-1 may be located between an edge or a peripheral edge and a central portion of the display panel 100 in the first area a1 of the display panel 100. For example, the first vibration module 200-1 may be disposed in an upper left area adjacent to an edge or a peripheral edge of the display panel 100 in the first area a1 of the display panel 100 with respect to the first direction X.

The third vibration module 200-3 may be located in the first area a1 of the display panel 100. As another example, the third vibration module 200-3 may be close to the center line CL of the display panel 100 in the first area a1 of the display panel 100 with respect to the first direction X. The third vibration module 200-3 according to one embodiment may be located between the center line CL of the display panel 100 and the center portion of the first area a 1. For example, the third vibration module 200-3 may be located in a right lower area adjacent to the center line CL of the display panel 100 in the first area a1 of the display panel 100 with respect to the first direction X. The third vibration modules 200-3 may be alternately disposed with the first vibration modules 200-1 in the first area a1 of the display panel 100. Accordingly, the third vibration module 200-3 may not overlap the first vibration module 200-1 in the first and second directions X and Y.

The second vibration module 200-2 may be located in the second area a2 of the display panel 100. As another example, the second vibration module 200-2 may be near an edge or a periphery of the display panel 100 in the second area a2 of the display panel 100 with respect to the first direction X. The second vibration module 200-2 according to an embodiment may be located between an edge or a peripheral edge and a central portion of the display panel 100 in the second area a2 of the second vibration module 200-2. For example, the second vibration module 200-2 may be located in an upper right area adjacent to an edge or a peripheral edge of the display panel 100 in the second area a2 of the display panel 100 with respect to the first direction X. In addition, the first vibration module 200-1 may be laterally symmetrical to the second vibration module 200-2 with respect to the center line CL of the display panel 100.

The fourth vibration module 200-4 may be located in the second area a2 of the display panel 100. As another example, the fourth vibration module 200-4 may be close to the center line CL of the display panel 100 in the second area a2 of the display panel 100 with respect to the first direction X. The fourth vibration module 200-4 according to one embodiment may be located between the center line CL of the display panel 100 and the central portion of the second area a 2. For example, the fourth vibration module 200-4 may be located in a lower left area adjacent to the center line CL of the display panel 100 in the second area a2 of the display panel 100 with respect to the first direction X. The fourth vibration module 200-4 may be alternately disposed with the second vibration module 200-2 in the second area a2 of the display panel 100. Accordingly, the fourth vibration module 200-4 may not overlap the second vibration module 200-2 in the first direction X and the second direction Y. In addition, the third vibration module 200-3 may be laterally symmetrical to the fourth vibration module 200-4 with respect to the center line CL of the display panel 100.

Each of the first to fourth vibration modules 200-1 to 200-4 may further include a first electrode layer, which may be located on the first surface of the piezoelectric composite layer PCL and may be electrically connected to each of the first surfaces of the plurality of first portions 210. Each of the first to fourth vibration modules 200-1 to 200-4 may further include a second electrode layer, which may be on a second surface of the piezoelectric composite layer PCL opposite to the first surface and may be electrically connected to a second surface of each of the plurality of first portions 210. In addition, each of the first to fourth vibration modules 200-1 to 200-4 may further include a first protective film covering the first electrode layer and a second protective film covering the second electrode layer. The first electrode layer, the second electrode layer, the first protective film, and the second protective film are as described above. Therefore, a repetitive description thereof will be omitted.

The display apparatus according to another embodiment of the present disclosure may further include: a first plate 700 positioned between the third vibration module 200-3 and the display panel 100; and a second plate 710 between the fourth vibration module 200-4 and the display panel 100.

The first plate 700 may be coupled or connected to each of the third vibration module 200-3 and the display panel 100, for example, by an adhesive member. The first plate 700 may transmit the vibration of the third vibration module 200-3 to the display panel 100. In addition, the first plate 700 may reinforce the mass of the third vibration module 200-3 to reduce the resonant frequency of the third vibration module 200-3 based on the increase in the mass. Accordingly, the first plate 700 may increase the sound pressure characteristic of the low-pitched sound band of the third vibration module 200-3, thereby enhancing the flatness of the sound pressure characteristic based on the vibration of the display panel 100.

The second plate 710 may be coupled or connected to each of the fourth vibration module 200-4 and the display panel 100 by an adhesive member. The second plate 710 may transmit the vibration of the fourth vibration module 200-4 to the display panel 100. In addition, the second plate 710 may reinforce the mass of the fourth vibration module 200-4 to reduce the resonance frequency of the fourth vibration module 200-4 based on the increase in the mass. Accordingly, the second plate 710 may increase the sound pressure characteristic of the low-pitched sound band of the fourth vibration module 200-4, thereby enhancing the flatness of the sound pressure characteristic based on the vibration of the display panel 100.

Each of the first plate 700 and the second plate 710 according to the embodiment may include a material containing one or more of stainless steel, Al, Mg alloy, Mg — Li alloy, and Al alloy, but the embodiment is not limited thereto.

The display apparatus according to another embodiment of the present disclosure may further include a spacer 600 between the display panel 100 and the rear structure 300. The partition 600 according to the present embodiment may be substantially similar to the partition 600 described above with reference to fig. 15, except that the fourth and fifth partition members 640 and 650 each have a quadrangular or quadrangular shape. Therefore, a repetitive description thereof will be omitted. The fourth partition member 640 and the fifth partition member 650 shown in fig. 18 may each have a circular shape.

Accordingly, the display apparatus according to another embodiment of the present disclosure may output left and right sounds through the first and third vibration modules 200-1 and 200-3 located in the first area a1 of the display panel 100 and the second and fourth vibration modules 200-2 and 200-4 disposed in the second area a2 of the display panel 100 to provide stereo sound to the user. In addition, in the display device according to another embodiment of the present disclosure, the vibration areas of the first and third vibration modules 200-1 and 200-3 based on the diagonal direction of the first region a1 and the vibration areas of the second and fourth vibration modules 200-2 and 200-4 based on the diagonal direction of the second region a2 may be increased. Accordingly, by coupling or connecting the first and second plates 700 and 710 of the third and fourth vibration modules 200-3 and 200-4, respectively, the pressure characteristic of the low-pitched vocal cords may be increased and the resonance frequency may be decreased, thereby enhancing the flatness of the sound pressure characteristic. In addition, the display apparatus according to the present embodiment may separate left and right sounds by using the partition 600 to output two-channel stereo sound.

Fig. 19A to 19C are diagrams illustrating various display devices to which the flexible vibration module according to the embodiment of the present disclosure may be applied.

Fig. 19A to 19C illustrate a display device to which the flexible vibration module shown in any one of fig. 4 to 13 can be applied.

The flexible vibration module according to the embodiment of the present disclosure may be implemented as a film type having flexibility. Accordingly, the embodiments may be applied to various application devices.

Referring to fig. 19A, the flexible vibration module 200 according to the embodiment of the present disclosure may be applied to a commercial display device or a flexible display device including a display panel 100, the display panel 100 including a plurality of curved surface portions CSP1 to CSP5 that may be concave or convex. For example, the flexible vibration module 200 may be implemented to be bent in a shape having a curvature value (e.g., a radius of curvature) matching a convex portion or a concave portion of each of the curved surface portions CSP1 through CSP5 of the display panel 100, and may be located in the convex portion or the concave portion of each of the curved surface portions CSP1 through CSP5 of the display panel 100. As another example, the flexible vibration module 200 may be implemented to have a shape matching a curvature value (e.g., a radius of curvature) of each of the curved surface portions CSP1 through CSP5 of the display panel 100, and may be located on the entire (or all) rear surface of the display panel 100.

Referring to fig. 19B, the flexible vibration module 200 according to the embodiment of the present disclosure may be applied to a rollable display device including the display panel 100 that may be wound in a spiral shape or unwound. For example, the flexible vibration module 200 according to an embodiment of the present disclosure may be implemented to have a shape having a curvature value (e.g., a curvature radius) of the display panel 100 that may be wound in a spiral shape or unwound, and a plurality of flexible vibration modules 200 may be arranged on the rear surface of the display panel 100 at certain intervals. As another example, the flexible vibration module 200 may be implemented to have a shape matching a curvature value (e.g., a radius of curvature) of the display panel 100, and may be located on the entire rear surface of the display panel 100.

Referring to fig. 19C, the flexible vibration module 200 according to the embodiment of the present disclosure may be applied to a wearable display device including a display panel 100, which display panel 100 may be wound around a wrist of a user and may be bent in a "C" shape. For example, the flexible vibration module 200 according to an embodiment of the present disclosure may be implemented to have a shape having a curvature value (e.g., a curvature radius) of the display panel 100 that may be bent in a "C" shape, and a plurality of flexible vibration modules 200 may be arranged on the rear surface of the display panel 100 at certain intervals. As another example, the flexible vibration module 200 may be implemented to have a shape matching a curvature value (e.g., a radius of curvature) of the display panel 100 that may be bent in a C-shape, and may be located on the entire rear surface of the display panel 100.

Fig. 20A to 20C are diagrams illustrating a method of manufacturing a flexible vibration module according to an embodiment of the present disclosure.

Fig. 20A to 20C illustrate a method of manufacturing the flexible vibration module according to the embodiment shown in any one of fig. 4 to 8. Therefore, hereinafter, detailed descriptions of elements of the flexible vibration module are omitted. A method of manufacturing a flexible vibration module according to an embodiment of the present disclosure will be described below with reference to fig. 20A to 20C.

First, the plate-shaped inorganic material mother substrate 210a having piezoelectric characteristics may be manufactured through a pretreatment.

The pre-treatment according to one embodiment may mix and dry the ceramic raw materials, may crystallize the crystal structure through a calcination (e.g., firing) process, and may manufacture the plate-shaped inorganic material mother substrate 210a by performing at least one molding process and sintering process. For example, the plate-shaped inorganic material mother substrate 210a may include a piezoelectric ceramic having a perovskite-based crystal structure. The sintering process may use one or more of heat, pressure, and spark plasma. The plate-shaped inorganic material mother substrate 210a may have a first width (e.g., thickness) d 1.

Next, the piezoelectric composite layer PCL including a plurality of inorganic material portions 210 and a plurality of organic material portions 220 each disposed between the plurality of inorganic material portions 210 may be manufactured by performing post-processing shown in fig. 20A and 20B based on the plate-shaped inorganic material mother substrate 210A and the organic material having flexibility.

A method of manufacturing the piezoelectric composite layer PCL according to the embodiment will be described below.

As shown in fig. 20A, a laminated composite SC including a plurality of inorganic material mother substrates 210A and a plurality of organic material layers 220A each disposed between the plurality of inorganic material mother substrates 210A may be provided. For example, the laminated composite SC may be manufactured by repeatedly performing a process of forming an organic material layer 220a having a second width (e.g., thickness) d2 on an inorganic material mother substrate 210a and a process of placing another inorganic material mother substrate 210a on the organic material layer 220 a.

Next, the plurality of organic material layers 220a included in the laminated composite SC may be cured through a curing process.

Next, as shown in fig. 20B, a film type piezoelectric composite layer PCL in which a plurality of inorganic material portions 210 cut from each of a plurality of inorganic material mother substrates 210a and a plurality of organic material portions 220 cut from each of a plurality of organic material layers 220a are alternately arranged may be manufactured by cutting the laminated composite SC in units of a certain size through a cutting process. For example, the cutting process may be performed by at least one of a wire saw cutting process, a scribing process, a blade cutting process, a laser cutting process, a stealth cutting process, and a Thermal Laser Separation (TLS) process, but the embodiment is not limited thereto.

Next, as shown in fig. 20C, a first electrode layer 230 may be formed on a first surface of the piezoelectric composite layer PCL, and a second electrode layer 240 may be formed on a second surface of the piezoelectric composite layer PCL opposite to the first surface.

Next, polarization of each of the plurality of inorganic material portions 210 located in the piezoelectric composite layer PCL may be formed by a polarization process of applying a certain voltage to the first electrode layer 230 and the second electrode layer 240 in a certain temperature atmosphere or a temperature atmosphere that may be changed from a high temperature to a room temperature.

Next, a pad connected to each of the first electrode layer 230 and the second electrode layer 240 may be formed, and a protective film covering the first electrode layer 230 and the second electrode layer 240 may be formed, thereby completing post-processing performed on the flexible vibration module.

In the method of manufacturing a flexible vibration module according to the embodiment of the present disclosure, the film-type piezoelectric composite layer PCL may be manufactured by performing a cutting process once on the laminated composite SC including the plurality of inorganic material mother substrates 210a and the plurality of organic material layers 220a each disposed between two adjacent inorganic material mother substrates among the plurality of inorganic material mother substrates 210 a. This can simplify the process of manufacturing the piezoelectric composite layer PCL or shorten the time taken for the process of manufacturing the piezoelectric composite layer PCL.

Fig. 21A to 21D are views illustrating a method of manufacturing a flexible vibration module according to another embodiment of the present disclosure.

Fig. 21A to 21D illustrate a method of manufacturing the flexible vibration module according to the embodiment shown in any one of fig. 4 to 8. Therefore, hereinafter, detailed descriptions of elements of the flexible vibration module are omitted. A method of manufacturing a flexible vibration module according to another embodiment of the present disclosure will be described below with reference to fig. 21A to 21D.

First, a plate-shaped inorganic material mother substrate having piezoelectric characteristics can be manufactured by pretreatment. The pretreatment is substantially similar to the pretreatment described above. Therefore, a repetitive description thereof is omitted.

Next, the piezoelectric composite layer PCL including a plurality of inorganic material portions 210 and a plurality of organic material portions 220 each disposed between the plurality of inorganic material portions 210 may be manufactured by performing post-processing illustrated in fig. 21A to 21C based on the plate-shaped inorganic material mother substrate 210a and the organic material having flexibility.

A method of manufacturing the piezoelectric composite layer PCL according to the embodiment will be described below.

As shown in fig. 21A, a plurality of inorganic material mother substrates 210a may be sequentially stacked, and a plurality of inorganic material portions 210 (e.g., inorganic material strips) cut into a line shape from each of the plurality of inorganic material mother substrates 210a may be manufactured by simultaneously cutting the stacked plurality of inorganic material mother substrates 210a in units of a specific first width d1 through a cutting process. For example, the cutting process may be performed by at least one of a wire saw cutting process, a scribing process, a blade cutting process, a laser cutting process, a stealth cutting process, and a Thermal Laser Separation (TLS) process, but the embodiment is not limited thereto.

Next, as shown in fig. 21B, a frame 1000 (e.g., a tray) including an opening corresponding to the size of the flexible vibration module may be disposed on the stage. A plurality of inorganic material portions 210 may be arranged in the opening of the frame 1000 at a certain interval d 2.

Next, as shown in fig. 21C, an organic material may be filled between the plurality of inorganic material portions 210 located in the opening of the frame 1000. Then, the plurality of organic material portions 220 having flexibility may be formed by curing the organic material through a curing process, thereby manufacturing the film-type piezoelectric composite layer PCL in which the plurality of organic material portions 220 and the plurality of inorganic material portions 210 are alternately arranged in the first direction X.

Next, the organic material remaining on the film-type piezoelectric composite layer PCL may be removed, and the film-type piezoelectric composite layer PCL from which the organic material is removed may be unloaded from the frame 1000.

Next, as shown in fig. 21D, a first electrode layer 230 may be formed on a first surface of the piezoelectric composite layer PCL, and a second electrode layer 240 may be formed on a second surface of the piezoelectric composite layer PCL opposite to the first surface.

Next, polarization of each of the plurality of inorganic material portions 210 located in the piezoelectric composite layer PCL may be formed by a polarization process of applying a certain voltage to the first electrode layer 230 and the second electrode layer 240 in a certain temperature atmosphere or a temperature atmosphere that may be changed from a high temperature to a room temperature.

Next, a pad connected to each of the first electrode layer 230 and the second electrode layer 240 may be formed, and a protective film covering the first electrode layer 230 and the second electrode layer 240 may be formed, thereby completing post-processing performed on the flexible vibration module.

In a method of manufacturing a flexible vibration module according to another embodiment of the present disclosure, the film-type piezoelectric composite layer PCL having various sizes may be manufactured by adjusting the interval or distance between the plurality of inorganic material portions 210 in the opening of the frame 1000.

Fig. 22A to 22F are diagrams illustrating a method of manufacturing a flexible vibration module according to another embodiment of the present disclosure.

Fig. 22A to 22F illustrate a method of manufacturing the flexible vibration module shown in fig. 11. Therefore, hereinafter, detailed descriptions of elements of the flexible vibration module are omitted. A method of manufacturing a flexible vibration module according to another embodiment of the present disclosure will be described below with reference to fig. 22A to 22F.

First, a plate-shaped inorganic material mother substrate having piezoelectric characteristics can be manufactured by pretreatment. The pretreatment is substantially similar to the pretreatment described above. Therefore, a repetitive description thereof is omitted.

Next, the piezoelectric composite layer PCL including a plurality of inorganic material portions 210 and a plurality of organic material portions 220 each disposed between the plurality of inorganic material portions 210 may be manufactured by performing post-processing illustrated in fig. 22A to 22E based on the plate-shaped inorganic material mother substrate 210a and the organic material having flexibility.

A method of manufacturing the piezoelectric composite layer PCL according to the embodiment will be described below.

As shown in fig. 22A, a single inorganic material mother substrate 210a may be positioned on a rotatable stage 1100, a cutting apparatus having a cutting path disposed in a second direction Y (e.g., a length direction) may be aligned on the stage 1100, and a first-order first cutting area CA1 of a plurality of first cutting areas CA1 (e.g., cutting areas in a length direction) previously disposed on the inorganic material mother substrate 210a may be aligned on the cutting path of the cutting apparatus by rotating and moving the stage 1100. Next, each of the first cutting areas CA1 of the inorganic material mother substrates 210a aligned on the cutting path may be sequentially cut by the linear motion of the stage 1100 and the first cutting process performed by the cutting apparatus, thereby separating the single inorganic material mother substrate 210a into a plurality of inorganic material mother substrates 210a in the length direction. For example, a single inorganic material mother substrate 210a may be separated (e.g., patterned) into four inorganic material mother substrates 210a through three first cutting processes.

Next, as shown in fig. 22B, the stage 1100 may be rotated forwardly by 90 ° (degrees) with respect to the origin, and then, the first-order second cutting regions CA2 of the plurality of second cutting regions CA2 (e.g., cutting regions in the width direction) provided in advance on the inorganic material mother substrate 210a may be aligned on the cutting path of the cutting apparatus. Subsequently, the second cutting area CA2 of the inorganic material mother substrates 210a aligned on the cutting path may be cut by the linear motion of the stage 1100 and the second cutting process performed by the cutting apparatus, thereby dividing each of the plurality of inorganic material mother substrates 210a into two inorganic material mother substrates 210a in the width direction. For example, four inorganic material mother substrates 210a obtained by patterning based on the first cutting process may be separated (e.g., patterned) into eight inorganic material mother substrates 210a by one second cutting process.

Next, as shown in fig. 22C, the stage 1100 may be rotated in the forward direction by 45 ° (degrees), and then, the first-order third cutting regions CA3 of the plurality of third cutting regions CA3 (e.g., cutting regions in the first diagonal direction) previously provided on the inorganic material mother substrate 210a may be aligned on the cutting path of the cutting apparatus. Next, each of the third cutting areas CA3 of the inorganic material mother substrates 210a aligned on the cutting path may be sequentially cut by the linear motion of the stage 1100 and the third cutting process performed by the cutting apparatus, thereby dividing each of the plurality of inorganic material mother substrates 210a into two inorganic material mother substrates 210a in the first diagonal direction. For example, eight inorganic material mother substrates 210a obtained by patterning based on the second cutting process may be separated (e.g., patterned) into sixteen inorganic material mother substrates 210a by five third cutting processes.

Next, as shown in fig. 22D, the stage 1100 rotated by 135 ° (degrees) may be reversely rotated by 90 ° (degrees) with respect to the origin, and then, first-order fourth cutting regions CA4 of a plurality of fourth cutting regions CA4 (e.g., cutting regions in a second diagonal direction) previously provided on the inorganic material mother substrate 210a may be aligned on the cutting path of the cutting device. Next, each of the fourth cutting areas CA4 of the inorganic material mother substrates 210a aligned on the cutting path may be cut by the linear motion of the stage 1100 and the fourth cutting process performed by the cutting apparatus, thereby additionally dividing each of the plurality of inorganic material mother substrates 210a into two inorganic material mother substrates 210a in the second diagonal direction, thereby finally forming a plurality of inorganic material portions 210 having a triangular shape. For example, sixteen inorganic material mother substrates 210a obtained through patterning based on the third cutting process may be separated (e.g., patterned) into thirty-two inorganic material portions 210 through the fifth fourth cutting process. Four adjacent inorganic material portions 210 among the plurality of inorganic material portions 210 having a triangular shape may be disposed adjacent to each other to form a quadrangular or quadrangular shape (e.g., a square shape), and vertices of the four adjacent inorganic material portions 210 may be disposed adjacent to each other in a central portion of the quadrangular shape.

In the cutting process performed on the inorganic material mother substrate 210a, the cutting regions CA1 to CA4 of the inorganic material mother substrate 210a may be aligned on the cutting path by the rotation and linear motion of the stage 1100 based on the cutting regions CA1 to CA4 defined on the inorganic material mother substrate 210a and the cutting path of the cutting apparatus. By repeating the process of cutting the aligned cut regions CA1 to CA4 of the inorganic material mother substrate 210a, the inorganic material mother substrate 210a can be finally separated (e.g., patterned) into a plurality of inorganic material portions 210 having a triangular shape. Accordingly, a single inorganic material mother substrate 210a may be patterned into a plurality of inorganic material portions 210 through a first cutting process in a length direction, a second cutting process in a width direction, a third cutting process in a first diagonal direction, and a fourth cutting process in a second diagonal direction. The cutting process performed on the inorganic material mother substrate 210a may form inorganic material portions having various shapes, thereby enhancing a degree of freedom in designing the shape of the inorganic material portions.

Next, as shown in fig. 22E, a frame 1200 including an opening corresponding to the size of the flexible vibration module may be located on the stage 1100, an organic material may be filled between two adjacent inorganic material portions of the plurality of inorganic material portions 210 and between each of the plurality of inorganic material portions 210 and the opening of the frame 1200, and the organic material portion 220 having flexibility may be formed by curing the organic material through a curing process, thereby manufacturing a film-type piezoelectric composite layer PCL including a plurality of inorganic material portions 210 each having a triangular shape and spaced apart from each other and an organic material portion 220 surrounding each of the plurality of inorganic material portions 210.

Next, the organic material remaining on the film-type piezoelectric composite layer PCL may be removed, and the film-type piezoelectric composite layer PCL from which the organic material is removed may be unloaded from the frame 1200.

Next, as shown in fig. 22F, a first electrode layer 230 may be formed on a first surface of the piezoelectric composite layer PCL, and a second electrode layer 240 may be formed on a second surface of the piezoelectric composite layer PCL opposite to the first surface.

Next, polarization of each of the plurality of inorganic material portions 210 located in the piezoelectric composite layer PCL may be formed by a polarization process of applying a certain voltage to the first electrode layer 230 and the second electrode layer 240 in a certain temperature atmosphere or a temperature atmosphere that may be changed from a high temperature to a room temperature.

Next, a pad connected to each of the first electrode layer 230 and the second electrode layer 240 may be formed, and a protective film covering the first electrode layer 230 and the second electrode layer 240 may be formed, thereby completing post-processing performed on the flexible vibration module.

As another example, as shown in fig. 12, the cutting process of the single inorganic material mother substrate 210a may cut the single inorganic material mother substrate 210 a. Accordingly, six adjacent inorganic material portions 210 having a triangular shape may be arranged in a hexagonal shape.

In a method of manufacturing a flexible vibration module according to another embodiment of the present disclosure, a single inorganic material mother substrate 210a may be patterned into a plurality of inorganic material portions 210 having a triangular shape by using a cutting process and rotation of a stage 1100. Therefore, the inorganic material portion having various shapes can be formed, thereby enhancing the degree of freedom in designing the shape of the inorganic material portion.

Fig. 23 is a graph showing an experimental result of sound pressure characteristics based on the presence or absence of the display panel having the flexible vibration module provided according to the first embodiment and the thin film speaker provided according to the comparative example.

In the sound pressure measurement of fig. 23, APx525 of Audio Precision was used, sinusoidal scanning was applied at 200Hz to 20kHz, and the sound pressure was measured at a position spaced apart from the display panel, the flexible vibration module, and the film speaker by 1 cm. The sinusoidal scanning may be a process of performing scanning in a short time, but the process is not limited thereto. In fig. 23, the abscissa axis (x-axis) represents a frequency in hertz (Hz), and the ordinate axis (y-axis) represents a sound pressure level in decibels (dB).

In the flexible vibration module of the first embodiment, PZT inorganic material portions and PVDF organic material portions each having a pattern interval of 10mm were formed and prepared, and top and bottom electrodes were formed and prepared, and a V30OLED display panel manufactured by LG electronics was used. In addition, the flexible vibration module prepared according to the first embodiment is attached to the display panel by using a double-sided tape.

In the film speaker of the comparative example, CS-510 of Fils corporation was prepared. A PVDF organic piezoelectric layer is formed, and mesh electrodes are formed above and below the PVDF organic piezoelectric layer, thereby manufacturing a CS-510 thin film speaker. For example, the electrode may include poly (3, 4-ethylenedioxythiophene) (PEDOT) and Carbon Nanotubes (CNTs), but the embodiment is not limited thereto. In addition, the film speaker is attached to the OLED display panel of the first embodiment by using a double-sided tape.

Referring to fig. 23, before the flexible vibration module is attached to the display panel, it can be seen that the film speaker prepared according to the comparative example (as indicated by a thick solid line) outputs a good sound pressure level in the high sound band, compared to the flexible vibration module prepared according to the first embodiment of the present disclosure (as indicated by a thick dotted line). However, after the flexible vibration module is attached to the OLED display panel, it can be seen that the display device prepared according to the first embodiment of the present disclosure outputs a sound pressure level about 15dB to about 20dB higher in all audible frequency bands (as indicated by the thin dotted line) as compared to the display device of the comparative example (as indicated by the thin solid line). The audible band may be, for example, 20Hz to 20kHz, but the range is not limited thereto.

Therefore, when the display device including the flexible vibration module according to the embodiment of the present disclosure is positioned on the rear surface of the display panel and vibrates the display panel to output sound to the front area in front of the display panel, it can be seen through experimental results that the performance of the display device including the flexible vibration module according to the embodiment of the present disclosure is better than that of the film speaker of the comparative example. In addition, when the film speaker of the comparative example is applied to a display device, it can be seen that the film speaker of the comparative example cannot realize a display device that outputs desired sound.

Fig. 24 is a graph illustrating an experimental result of sound pressure characteristics of an organic light emitting diode display panel to which the flexible vibration module according to the first to third embodiments of the present disclosure is attached.

In the sound pressure measurement of fig. 24, APx525 of Audio Precision was used, sinusoidal scanning was applied at 200Hz to 20kHz, and the sound pressure was measured at a position spaced apart from the display panel, the flexible vibration module, and the film speaker by 1 cm. In fig. 24, the abscissa axis (x-axis) represents a frequency in hertz (Hz), and the ordinate axis (y-axis) represents a sound pressure level in decibels (dB).

As shown in fig. 24, it can be seen that the display panel having the flexible vibration module according to the second embodiment of the present disclosure attached thereto, shown in fig. 6, outputs a good sound pressure level in a high-pitched sound zone, as compared to the display panel having the flexible vibration module according to the first embodiment of the present disclosure attached thereto, shown in fig. 4, shown in a dotted line. In addition, as compared with the display panel (as indicated by the dotted line) to which the flexible vibration module according to the first embodiment of the present disclosure is attached, it can be seen that the display panel (as indicated by the thick solid line) to which the flexible vibration module according to the third embodiment of the present disclosure shown in fig. 7 is attached outputs a high sound pressure level in the low-pitched and high-pitched sound bands, and outputs a sound pressure level about 10dB higher in all audible frequency bands. In addition, it can be seen that the display panel having the flexible vibration module according to the third embodiment of the present disclosure attached thereto, shown in fig. 7, outputs a sound pressure level higher by about 5dB to about 10dB in the mid-low tone vocal cords, as compared to the display panel having the flexible vibration module according to the second embodiment of the present disclosure attached thereto, shown in thin solid lines.

Therefore, in the flexible vibration module according to the present disclosure, it can be seen through experimental results that the sound pressure characteristic of a high-pitched sound band sound is improved when the size of the inorganic material part is increased compared to the content of the same inorganic material part, and it can be seen that the sound pressure characteristic is improved in all audible frequencies when the size of each of the organic material part and the inorganic material part is increased compared to the content of the same inorganic material part. Therefore, in the display device including the flexible vibration module according to the present disclosure, the size of each of the organic material portion and the inorganic material portion may be adjusted based on the sound pressure characteristic of the vocal cords to be realized by the vibration of the display panel. Therefore, the sound of a desired vocal cord can be easily realized according to the embodiment of the present disclosure.

Fig. 25 is a graph illustrating an experimental result of sound pressure characteristics of an organic light emitting diode display panel having the flexible vibration module according to the first to fourth embodiments of the present disclosure attached thereto.

In the sound pressure measurement of fig. 25, APx525 of Audio Precision was used, sinusoidal scanning was applied at 200Hz to 20kHz, and the sound pressure was measured at a position spaced apart from the display panel, the flexible vibration module, and the film speaker by 1 cm. In fig. 25, the abscissa axis (x-axis) represents a frequency in hertz (Hz), and the ordinate axis (y-axis) represents a sound pressure level in decibels (dB).

As shown in fig. 25, compared to the flexible vibration module according to the first embodiment of the present disclosure shown in fig. 4 (as indicated by the dotted line), it can be seen that the flexible vibration module according to the fourth embodiment of the present disclosure shown in fig. 8 (as indicated by the solid line) outputs a sound pressure level in the vocal cords of 300Hz or more and solves the problem of the drop of sound pressure occurring in about 300Hz to about 1kHz, thereby improving the flatness of the sound pressure level.

Therefore, as can be seen from the experimental results, the curved display device to which the flexible vibration module according to the fourth embodiment of the present disclosure is applied realizes a flat sound pressure characteristic and a high sound pressure level in a 300Hz or higher sound band due to the organic material portion having a wide size (e.g., width) in a region where stress is concentrated and a narrow size (e.g., width) in a region where stress is reduced or minimized.

The flexible vibration module according to the embodiment of the present disclosure may be applied as a sound generating apparatus provided in a display device. The display device according to an embodiment of the present disclosure may be applied to a mobile device, a video phone, a smart watch, a watch phone, a wearable device, a foldable device, a rollable device, a bendable device, a flexible device, a bending apparatus, an electronic notebook, an electronic book, a Portable Multimedia Player (PMP), a Personal Digital Assistant (PDA), an electronic notebook, a desktop Personal Computer (PC), a laptop computer, a netbook computer, a workstation, a navigation device, a car display device, a Television (TV), a wallpaper display device, a signage device, a game machine, a notebook computer, a monitor, a camera, a camcorder, a home appliance, and the like. In addition, the flexible vibration module according to the embodiment of the present disclosure may be applied to an organic light emitting lighting device or an inorganic light emitting lighting device. When the flexible vibration module according to the present disclosure is applied to a lighting device, the flexible vibration module may be used as a lighting and a speaker. In addition, when the flexible vibration module according to the present disclosure is applied to a mobile device, the flexible vibration module may be used as a speaker or a receiver.

A display device including a flexible vibration module and a method of manufacturing the flexible vibration module according to the present disclosure will be described below.

According to an embodiment of the present disclosure, a display device includes a display panel configured to display an image; and a flexible vibration module on a rear surface of the display panel, the flexible vibration module configured to vibrate the display panel, wherein the flexible vibration module may include: a plurality of first portions having piezoelectric properties; and a plurality of second portions respectively located between respective pairs of the plurality of first portions, the plurality of second portions having flexibility.

For example, in a display device according to an embodiment of the present disclosure, each of the plurality of first portions may include a non-flexible inorganic material, and each of the plurality of second portions may include a flexible organic material.

For example, in a display device according to an embodiment of the present disclosure, each of the plurality of first portions may include at least one of an organic piezoelectric material and an organic non-piezoelectric material. For example, in a display device according to an embodiment of the present disclosure, the flexible organic material may be configured to absorb an impact applied to the flexible vibration module or to the display device.

For example, in the display device according to the embodiment of the present disclosure, the plurality of first portions and the plurality of second portions may be juxtaposed on the same plane, and a size of each of the plurality of first portions may be the same as or different from a size of each of the plurality of second portions.

For example, in the display device according to the embodiment of the present disclosure, each of the plurality of first portions may have one of a linear shape, a circular shape, an oval shape, a triangular shape, and a polygonal shape.

For example, in the display device according to the embodiment of the present disclosure, the plurality of first portions and the plurality of second portions may be juxtaposed on the same plane, and a size of each successive second portion of the plurality of second portions may be reduced in comparison with a previous one of the plurality of second portions in a direction from the central portion to the peripheral portion of the flexible vibration module.

For example, in the display device according to the embodiment of the present disclosure, a second portion having a largest size among the plurality of second portions may be located in the central portion of the flexible vibration module.

For example, in the display device according to the embodiment of the present disclosure, each of the plurality of first portions may have a triangular shape, and may be adjacent to another one of the plurality of first portions to form a 2N-corner shape, where N is a natural number equal to or greater than 2.

For example, in a display device according to an embodiment of the present disclosure, the flexible vibration module may include: a first piezoelectric composite layer including a first set of the plurality of first portions and the plurality of second portions; a common electrode on the first piezoelectric composite layer; and a second piezoelectric composite layer on the common electrode, the second piezoelectric composite layer including a second group of the plurality of first portions and the plurality of second portions.

For example, in a display device according to an embodiment of the present disclosure, each of the plurality of first portions on the second piezoelectric composite layer: may respectively overlap with a corresponding one of the plurality of second portions on the first piezoelectric composite layer; or may respectively overlap with a corresponding one of the plurality of first portions on the first piezoelectric composite layer.

For example, in a display device according to an embodiment of the present disclosure, the display panel may include: a display area configured to display an image; and a non-display area surrounding the display area, and a size of the flexible vibration module may be 0.9 times to 1.1 times a size of the display area.

For example, in a display device according to an embodiment of the present disclosure, the display panel may include a display area configured to display an image; and the flexible vibration module may include: a first vibration module located in a first region of the display area, the first vibration module including a first group of the plurality of first portions and the plurality of second portions; and a second vibration module located in a second region of the display region, the second vibration module including a second group of the plurality of first portions and the plurality of second portions.

For example, in a display device according to an embodiment of the present disclosure, the flexible vibration module may further include: a third vibration module alternately disposed with the first vibration module in the first region of the display region, the third vibration module including a third group of the plurality of first portions and the plurality of second portions; and a fourth vibration module alternately disposed with the second vibration module in the second region of the display region, the fourth vibration module including a fourth group of the plurality of first portions and the plurality of second portions.

For example, the display device according to an embodiment of the present disclosure may further include: a first plate between the third vibration module and the display panel; and a second plate between the fourth vibration module and the display panel.

For example, in the display apparatus according to the embodiment of the present disclosure, each of the plurality of first portions may have a triangular shape, and may be disposed adjacent to another one of the plurality of first portions to form a 2N-corner shape, where N is a natural number equal to or greater than 2.

For example, the display device according to an embodiment of the present disclosure may further include: another flexible vibration module on the rear surface of the display panel, the another flexible vibration module configured to vibrate the display panel, the display panel may include: a first region, a second region, and a partition configured to divide the first region and the second region, the flexible vibration module may be located in the first region, and the other flexible vibration module may be located in the second region. For example, the display device according to an embodiment of the present disclosure may further include: a third flexible vibration module and a fourth flexible vibration module located on the rear surface of the display panel, each of the third and fourth flexible vibration modules configured to vibrate the display panel, the third flexible vibration module may be located in the first region and may be diagonally disposed with respect to the first flexible vibration module, and the fourth flexible vibration module may be located in the second region and may be diagonally disposed with respect to the second flexible vibration module.

According to an embodiment of the present disclosure, a display apparatus may include: a flexible display panel that can be spirally wound, unwound, or have a specific radius of curvature, the flexible display panel including a display area configured to display an image, and a flexible vibration module that is located on a rear surface of the flexible display panel to correspond to the display area and is bent based on the unwinding or winding of the display panel or is bent based on the curvature of the flexible display panel, the flexible vibration module including: a plurality of vibrating portions, and a plurality of elastic portions respectively located between respective pairs of the plurality of vibrating portions, the plurality of elastic portions having flexibility.

For example, in a display device according to an embodiment of the present disclosure, each of the plurality of vibration portions may include a non-flexible inorganic material having piezoelectric characteristics, and each of the plurality of elastic portions may include a flexible material including at least one of an organic piezoelectric material and an organic non-piezoelectric material. For example, in a display device according to an embodiment of the present disclosure, the flexible material may be configured to absorb an impact applied to the flexible vibration module or to the display device.

For example, in the display device according to the embodiment of the present disclosure, the plurality of vibration parts and the plurality of elastic parts may be juxtaposed on the same plane, and a size of each of the plurality of vibration parts may be the same as or different from a size of each of the plurality of elastic parts.

For example, the display apparatus according to an embodiment of the present disclosure may further include: another flexible vibration module on the rear surface of the flexible display panel to correspond to the display area and to be bent based on unrolling or rolling of the flexible display panel or to be bent based on a curvature of the flexible display panel, wherein the flexible display panel may include: a first region, a second region, and a partition configured to divide the first region and the second region, the flexible vibration module may be located in the first region, and the other flexible vibration module may be located in the second region.

For example, the display apparatus according to an embodiment of the present disclosure may further include: a third flexible vibration module and a fourth flexible vibration module which are located on the rear surface of the flexible display panel to correspond to the display area and to be bent based on unrolling or rolling of the flexible display panel or to be bent based on a curvature of the flexible display panel, the third flexible vibration module may be located in the first area and may be diagonally disposed with respect to the flexible vibration module, and the fourth flexible vibration module may be located in the second area and may be diagonally disposed with respect to the other flexible vibration module.

According to an embodiment of the present disclosure, a method of manufacturing a flexible vibration module may include the steps of: manufacturing a piezoelectric composite including a plurality of inorganic material portions and a plurality of organic material portions connected between the plurality of inorganic material portions, based on an inorganic material mother substrate having piezoelectric characteristics and an organic material having flexibility; forming a first electrode layer on a first surface of the piezoelectric composite and a second electrode layer on a second surface of the piezoelectric composite; applying a voltage to the first electrode layer and the second electrode layer in a temperature atmosphere to form a polarization of each of the plurality of inorganic material portions; and forming a protective film on each of the first electrode layer and the second electrode layer.

For example, in a method according to an embodiment of the present disclosure, each of the plurality of inorganic material portions may have a triangular shape and may be adjacent to another of the plurality of inorganic material portions to form a 2N-cornered shape, where N is a natural number equal to or greater than 2.

For example, in a method according to an embodiment of the present disclosure, the step of manufacturing the piezoelectric composite may include the steps of: manufacturing a laminated composite by repeating the following process; and forming a flexible organic material layer on the inorganic material mother substrate. And a process of laminating another inorganic material mother substrate on the flexible organic material layer; curing the flexible organic material layer laminated on the laminated composite; and cutting the laminated composite to a size to manufacture the piezoelectric composite having a film type, wherein each inorganic material mother substrate may include a non-flexible material.

For example, in a method according to an embodiment of the present disclosure, the step of manufacturing the piezoelectric composite may include: cutting the inorganic material mother substrate by a predetermined size to manufacture the plurality of inorganic material portions; arranging the plurality of inorganic material portions at predetermined intervals in an opening provided in a frame; and filling an organic material between the plurality of inorganic material portions and curing the organic material to form a plurality of organic material portions.

For example, in a method according to an embodiment of the present disclosure, the step of manufacturing the piezoelectric composite may include: placing the inorganic material mother substrate on a rotatable stage; aligning a cutting region of the inorganic material mother substrate and a cutting path of a cutting device by rotation and linear movement of the rotatable stage based on a plurality of cutting regions defined in the inorganic material mother substrate and the cutting path of the cutting device, and patterning the inorganic material mother substrate into the plurality of inorganic material portions by a cutting process of sequentially cutting the aligned cutting regions of the inorganic material mother substrate; placing a frame comprising an opening on the rotatable gantry; and filling an organic material between the plurality of inorganic material portions and between each of the plurality of inorganic material portions and the opening of the frame and curing the organic material to form the plurality of organic material portions.

For example, in a method according to an embodiment of the present disclosure, the plurality of cutting regions may include: a plurality of lengthwise cutting zones; cutting the area in the width direction; a plurality of first diagonal cutting zones; and a plurality of second diagonal cutting zones, and the cutting process may include the following processes: a first cutting process of cutting each of the plurality of lengthwise cutting regions; a second cutting process of cutting the width-direction cutting region; a third cutting process of cutting each of the plurality of first diagonal direction cutting regions; and a fourth cutting process of cutting each of the plurality of second diagonal direction cutting regions.

The above-described features, structures, and effects of the present disclosure are included in at least one embodiment of the present disclosure, but are not limited to only one embodiment. Furthermore, the features, structures, and effects described in at least one embodiment of the present disclosure can be achieved by a person skilled in the art by combining or modifying other embodiments. Therefore, the matters associated with the combination and modification should be construed as being within the scope of the present disclosure.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present disclosure without departing from the technical spirit or scope of the disclosure. Thus, it is intended that the embodiments of the present disclosure may cover the modifications and variations of this disclosure that fall within the scope of the appended claims and their equivalents.

Cross Reference to Related Applications

The present application claims the priority and benefit of korean patent application No. 10-2018-.