阅读说明：本技术 显示设备 (Display device ) 是由 李泰浩 刘俊优 根本笃志 于 2021-04-09 设计创作，主要内容包括：本发明涉及包括显示模块和设置在显示模块上的窗的显示设备。窗包括基础层以及树脂,该基础层包括折叠区域和非折叠区域,折叠区域中限定有凹槽,该树脂设置在凹槽中并且包括硫醇基团,其中,基础层的折射率与树脂的折射率之间的差小于约0.1。(The present invention relates to a display apparatus including a display module and a window provided on the display module. The window includes a base layer including a fold region and a non-fold region, the fold region having a groove defined therein, and a resin disposed in the groove and including a thiol group, wherein a difference between a refractive index of the base layer and a refractive index of the resin is less than about 0.1.)

1. A display device, comprising:

a display module; and

a window disposed on the display module, the window including:

a base layer comprising:

a fold region having a plurality of grooves defined therein; and

a non-folded region; and

a resin disposed in each of the plurality of grooves and including a thiol group,

wherein a difference between a refractive index of the base layer and a refractive index of the resin is less than 0.1.

2. The display device of claim 1, wherein each of the plurality of grooves comprises:

a first portion having a circular shape;

a second portion spaced apart from the first portion and having a circular shape; and

a third portion connecting the first portion and the second portion.

3. The display device of claim 2, wherein the width of the third portion comprises at least one of a first width and a second width greater than the first width.

4. The display device of claim 1, wherein:

the plurality of grooves includes a first groove defined in a central region of the fold region, a second groove defined in a peripheral region of the fold region, and a third groove defined in the peripheral region and closer to the non-fold region than the second groove to the non-fold region; and

the length of the gap between the first groove and the second groove is equal to the length of the gap between the second groove and the third groove.

5. The display device of claim 1, wherein:

the plurality of grooves includes a first groove defined in a central region of the fold region, a second groove defined in a peripheral region of the fold region, and a third groove defined in the peripheral region and closer to the non-fold region than the second groove to the non-fold region; and

the length of the gap between the first groove and the second groove is smaller than the length of the gap between the second groove and the third groove.

6. The display device according to claim 1, wherein the resin has translucency.

7. The display device according to claim 1, wherein the resin has elasticity.

8. The display device of claim 1, wherein the resin has a refractive index of 1.5 to 1.6.

9. The display device of claim 1, wherein the resin comprises polydimethylsiloxane thiol.

10. The display device according to claim 9, wherein the resin includes at least one of a thiol-based cross-linking agent polymerized with the polydimethylsiloxane thiol, an acrylic-based cross-linking agent, and a vinyl-based cross-linking agent.

Technical Field

Embodiments of the present invention relate to a window and a display apparatus having improved product reliability.

Background

The display device displays various images on a display screen to provide information to a user. Generally, a display device displays information within a designated screen. In recent years, flexible display devices including a foldable flexible display panel have been developed. Unlike rigid display devices, flexible display devices are deformable, e.g., foldable, rollable, or bendable. The flexible display device, which can be transformed into various shapes, is portable regardless of the existing screen size, thereby improving user convenience.

Disclosure of Invention

Embodiments of the present invention provide a display device having improved product reliability.

Embodiments of the present invention provide a window comprising a base layer comprising a fold region and a non-fold region, the fold region having a groove defined therein, and a resin disposed in the groove and comprising thiol groups, wherein a difference between a refractive index of the base layer and a refractive index of the resin is less than about 0.1.

In an embodiment, the refractive index of the resin may be about 1.5 to about 1.6.

In an embodiment, the groove may include a first portion having a circular shape, a second portion spaced apart from the first portion and having a circular shape, and a third portion connecting the first portion and the second portion.

In an embodiment, the third portion may have a curved shape.

In embodiments, the resin may include polydimethylsiloxane thiol.

In an embodiment, the resin may include at least one of a thiol-based cross-linking agent polymerized with polydimethylsiloxane thiol, an acrylic-based cross-linking agent, and a vinyl-based cross-linking agent.

In an embodiment, a plurality of grooves may be defined in the fold region.

In an embodiment, the resin may have translucency.

In embodiments, the base layer may have a thickness of about 100 micrometers (μm) to about 500 μm.

In an embodiment of the present invention, a display device includes a display module and a window disposed on the display module, the window including a base layer and a resin, the base layer including a folding region and a non-folding region, the folding region having a plurality of grooves defined therein, the resin being disposed in each of the plurality of grooves and including a thiol group, and a difference between a refractive index of the base layer and a refractive index of the resin being less than about 0.1.

In an embodiment, each of the plurality of grooves may include a first portion having a circular shape, a second portion spaced apart from the first portion and having a circular shape, and a third portion connecting the first portion and the second portion.

In an embodiment, the width of the third portion may include at least one of a first width and a second width greater than the first width.

In an embodiment, the plurality of grooves may include a first groove defined in a central region of the folding region, a second groove defined in a peripheral region of the folding region, and a third groove defined in the peripheral region and closer to the non-folding region than the second groove to the non-folding region, and a distance between the first groove and the second groove may be equal to a distance between the second groove and the third groove.

In an embodiment, the plurality of grooves may include a first groove defined in a central region of the folding region, a second groove defined in a peripheral region of the folding region, and a third groove defined in the peripheral region and closer to the non-folding region than the second groove to the non-folding region, and a distance between the first groove and the second groove may be smaller than a distance between the second groove and the third groove.

In an embodiment, the resin may have translucency.

In an embodiment, the resin may have elasticity.

In an embodiment, the resin may have a refractive index of about 1.5 to about 1.6.

In an embodiment, the window may have a thickness of about 100 μm to about 500 μm.

In embodiments, the resin may include polydimethylsiloxane thiol.

In an embodiment, the resin may include at least one of a thiol-based cross-linking agent polymerized with polydimethylsiloxane thiol, an acrylic-based cross-linking agent, and a vinyl-based cross-linking agent.

Drawings

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

FIG. 1A is a perspective view of an embodiment of a display device according to the present invention;

FIG. 1B is an operational state view of an embodiment of a display device according to the present invention;

FIG. 2 is a cross-sectional view of an embodiment of a display device according to the present invention;

FIG. 3 is a cross-sectional view of an embodiment of a display module according to the present invention;

FIG. 4 is a cross-sectional view of an embodiment of an upper layer according to the present invention;

FIG. 5 is a plan view of an embodiment of a window according to the present invention;

FIG. 6 is an enlarged view illustrating an embodiment of the area AA shown in FIG. 5;

FIG. 7 is a plan view of an embodiment of a base layer according to the present invention;

FIG. 8A is an enlarged view illustrating an embodiment of the area AA' shown in FIG. 7;

fig. 8B is an enlarged view illustrating an embodiment of an area AA' shown in fig. 7;

FIG. 9A is an enlarged view illustrating an embodiment of the area AA shown in FIG. 5;

FIG. 9B is an enlarged view illustrating an embodiment of the area AA shown in FIG. 5;

FIG. 10 is an enlarged plan view illustrating an embodiment of a portion of a foundation layer in accordance with the present invention; and

fig. 11 schematically shows an embodiment of a resin according to the present invention.

Detailed Description

In the present disclosure, when an element (or a region, layer, portion, or the like) is referred to as being "on," "connected to," or "coupled to" another element, it means that the element may be directly disposed on, directly connected/directly coupled to the other element, or a third element may be disposed therebetween.

Like reference numerals refer to like elements. In addition, in the drawings, thicknesses, ratios, and sizes of elements are exaggerated for effectively describing technical contents.

The term "and/or" includes all combinations of one or more that the associated configuration may define.

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 embodiments of the inventive concept. Terms in the singular may include the plural unless the context clearly dictates otherwise.

Further, terms such as "below", "lower", "above", "upper", and the like are used to describe the relationship of the configurations shown in the drawings. These terms are used as relative terms and are described with reference to the directions indicated in the drawings.

As used herein, "about" or "approximately" includes the stated value as well as the average value within an acceptable range of deviation of the specified value as determined by one of ordinary skill in the art taking into account the measurement in question and the error associated with the measurement of the specified quantity (i.e., the limitations of the measurement system). For example, "about" can mean within one or more standard deviations, or within ± 30%, ± 20%, ± 10%, ± 5% of the stated value.

Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the inventive concept belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

It will be understood that the terms "comprises" or "comprising," or "having," are intended to specify the presence of stated features, integers, steps, operations, elements, components, or groups thereof, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or groups thereof.

It is to be understood that terms such as "substantially the same" are intended to be inclusive of process errors that may generally occur with respect to the numerical ranges set forth in the specification. It should be understood that in the specification, the refractive index of the base layer being substantially the same as that of the resin indicates that the refractive index of the base layer and that of the resin are the same, and the difference in refractive index is very small, so that, for example, the optical path at the interface of the base layer and the resin remains the same.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

Fig. 1A is a perspective view of an embodiment of a display apparatus 1000 according to the present invention. Fig. 1B is an operation state view of an embodiment of a display apparatus 1000 according to the present invention.

Referring to fig. 1A and 1B, the display device 1000 may be activated according to an electric signal. In an embodiment, the display device 1000 may be, for example, a mobile phone, a tablet, a car navigation unit, a game console, or a wearable device, but is not limited thereto. In fig. 1A, a mobile phone is shown as an embodiment of the display device 1000.

The display device 1000 may be a foldable display device. The display apparatus 1000 may sequentially define a first non-folding region 1000NF1, a folding region 1000F, and a second non-folding region 1000NF2 along the first direction DR 1. That is, the fold region 1000F may be defined between the first 1000NF1 and second 1000NF2 non-fold regions.

In fig. 1A and 1B, one folding region 1000F and first and second non-folding regions 1000NF1 and 1000NF2 are illustrated, but the number of folding regions 1000F and first and second non-folding regions 1000NF1 and 1000NF2 is not limited thereto. In an embodiment, the display device 1000 may include more than two non-folding regions and a folding region disposed between the non-folding regions, for example.

The display apparatus 1000 may display an image through the effective area 1000A. In the deployed state, the active area 1000A may include a plane parallel to a plane defined by the first direction DR1 and the second direction DR 2. The thickness direction of the display apparatus 1000 may be parallel to a third direction DR3 intersecting the first direction DR1 and the second direction DR 2. Accordingly, a front surface (or an upper surface) and a rear surface (or a lower surface) of members constituting the display apparatus 1000 may be defined with respect to the third direction DR 3.

When the display apparatus 1000 is folded, the display surface of the first non-folding region 1000NF1 and the display surface of the second non-folding region 1000NF2 may face each other, and thus, the active region 1000A may not be exposed to the outside when the display apparatus 1000 is in a fully folded state. This state may be referred to as an folded-in state. However, this is merely an example, and the present invention is not limited thereto.

When the display apparatus 1000 is folded, the display surface of the first non-folding region 1000NF1 and the display surface of the second non-folding region 1000NF2 may face the outside. Therefore, in the folded state, the effective region 1000A may be exposed to the outside. This state may be referred to as the outer folded state. Further, the display apparatus 1000 may be capable of both inward and outward folding. In an embodiment, one fold region 1000F may be, for example, in-folded and out-folded. In alternative embodiments, the display device 1000 may include multiple fold regions, and some of them may be folded in and others may be folded out.

Fig. 2 is a cross-sectional view of an embodiment of a display device 1000 according to the present invention.

Referring to fig. 2, the display apparatus 1000 may include a display module 100, an upper layer 200, and a lower layer 300.

The display module 100 may display an image and sense an external input. The external input may be an input of a user. In an embodiment, the user's input may include various forms of external input, such as a portion of the user's body, light, heat, pen, or pressure.

The display module 100 may include a display panel 110 generating an image and an input sensor 120 acquiring coordinate information of an external input.

The display panel 110 may be a light emitting display panel, but is not particularly limited. In the embodiment, the display panel 110 may be, for example, an organic light emitting display panel or a quantum dot light emitting display panel. The emission layer of the organic light emitting display panel may include an organic light emitting material. The emission layer of the quantum dot light emitting display panel may include quantum dots, quantum rods, and the like.

The input sensor 120 may be disposed on the display panel 110. The input sensor 120 may sense an external input using a mutual capacitance method and/or a self-capacitance method. However, the method for sensing the external input is not limited to the above example.

The upper layer 200 may be disposed on the display module 100. The display module 100 may display an image in a direction toward the upper layer 200. The upper layer 200 is disposed on the display module 100 to protect the display module 100. A detailed description will be given later on with respect to the upper layer 200.

The lower layer 300 may be disposed under the display module 100. The lower layer 300 may protect the rear surface of the display module 100. In an embodiment, the lower layer 300 may include a synthetic resin film such as a polyimide film or a polyethylene terephthalate film, and a cushion layer disposed under the synthetic resin film to include, for example, sponge, foam, urethane resin, or the like.

Fig. 3 is a cross-sectional view of an embodiment of a display module 100 according to the present invention.

Referring to fig. 3, a case where the display panel 110 is an organic light emitting display panel will be described as an example.

The display panel 110 may include a base layer 111, and a circuit element layer 112, a display element layer 113, and a thin film encapsulation layer 114 sequentially disposed on the base layer 111. Although not separately shown, the display panel 110 may further include functional layers such as a buffer layer and a refractive index control layer.

The base layer 111 may include a synthetic resin layer. The synthetic resin layer is provided on a working substrate used in the manufacture of the display panel 110. Thereafter, a conductive layer and an insulating layer are provided on the synthetic resin layer. When the work substrate is removed, the synthetic resin layer may correspond to the foundation layer 111. The synthetic resin layer may include a thermosetting resin. In particular, the synthetic resin layer may be a polyimide-based resin layer, and the material is not particularly limited. In addition, the base layer 111 may include a glass substrate, a metal substrate, or an organic/inorganic composite substrate.

The circuit element layer 112 includes at least one insulating layer and circuit elements. Hereinafter, the insulating layer included in the circuit element layer 112 may also be referred to as an intermediate insulating layer. The intermediate insulating layer may include at least one intermediate inorganic film and/or at least one intermediate organic film. The circuit elements include signal lines, pixel drive circuits, and the like. The circuit element layer 112 can be provided by a process of forming an insulating layer, a semiconductor layer, and a conductive layer by coating, deposition, or the like, and a process of patterning the insulating layer, the semiconductor layer, and the conductive layer by a photolithography process.

The display element layer 113 includes a light-emitting element. The display element layer 113 may include an organic light emitting diode. The display element layer 113 may also include an organic film such as a pixel defining film.

The thin film encapsulation layer 114 seals the display element layer 113. The thin film encapsulation layer 114 includes at least one insulating layer. The thin film encapsulation layer 114 in the embodiment of the present invention may include at least one inorganic film (hereinafter, also referred to as an inorganic encapsulation film). The thin film encapsulation layer 114 in the embodiment of the present invention may include at least one organic film (hereinafter, also referred to as an organic encapsulation film) and at least one inorganic encapsulation film.

The inorganic encapsulation film protects the display element layer 113 from moisture/oxygen, and the organic encapsulation film protects the display element layer 113 from foreign substances such as dust particles. In the embodiment, the inorganic encapsulation film may include, for example, a silicon nitride layer, a silicon oxynitride layer, a silicon oxide layer, a titanium oxide layer, an aluminum oxide layer, or the like, and is not particularly limited thereto. The organic encapsulation film may include an acryl-based organic film, and is not particularly limited.

The input sensor 120 may include a base insulating layer 121, a first conductive layer 122, a first insulating layer 123, a second conductive layer 124, and a second insulating layer 125.

The base insulating layer 121 may be an inorganic layer including any one of silicon nitride, silicon oxynitride, and silicon oxide. In alternative embodiments, the base insulating layer 121 may be an organic layer including an epoxy resin, an acrylic resin, or an imide-based resin. The base insulating layer 121 may be directly disposed on the display panel 110. In alternative embodiments, the base insulating layer 121 may be disposed on a separate base layer, and the base layer may be bonded to the base insulating layer 121 and the display panel 110 by an adhesive member. In an alternative embodiment, the base insulating layer 121 may be omitted.

Each of the first conductive layer 122 and the second conductive layer 124 may include a sensing electrode or a signal line. Each of the first and second conductive layers 122 and 124 may have a single-layer structure or a multi-layer structure stacked along the third direction DR 3. The single conductive layer may include a metal layer or a transparent conductive layer. In an embodiment, the metal layer may include, for example, at least any one of molybdenum, silver, titanium, copper, aluminum, and alloys thereof. In an embodiment, the transparent conductive layer may include a transparent conductive oxide such as indium tin oxide ("ITO"), indium zinc oxide ("IZO"), zinc oxide (ZnO), or indium tin zinc oxide ("ITZO"). In addition, the transparent conductive layer may include a conductive polymer such as poly (3, 4-ethylenedioxythiophene) ("PEDOT"), metal nanowires, graphene, and the like.

The multiple conductive layers may include multiple metal layers. In an embodiment, the multi-layered metal layer may have a three-layered structure of titanium/aluminum/titanium, for example. The multilayer conductive layer may include at least one metal layer and at least one transparent conductive layer.

Each of the first insulating layer 123 and the second insulating layer 125 may have a single-layer structure or a multi-layer structure. Each of the first insulating layer 123 and the second insulating layer 125 may include an inorganic or organic material or a composite material.

At least any one of the first insulating layer 123 and the second insulating layer 125 may include an inorganic film. In an embodiment, the inorganic film may include at least one of aluminum oxide, titanium oxide, silicon oxynitride, zirconium oxide, and hafnium oxide, for example.

At least any one of the first insulating layer 123 and the second insulating layer 125 may include an organic film. In the embodiment, the organic film may include, for example, at least any one of an acrylic-based resin, a methacrylic-based resin, polyisoprene, a vinyl-based resin, an epoxy-based resin, a urethane-based resin, a cellulose-based resin, a silicone-based resin, a polyimide-based resin, a polyamide-based resin, and a perylene-based resin.

Fig. 4 is a cross-sectional view of an embodiment of an upper layer 200 according to the present invention. Fig. 5 is a plan view of an embodiment of a window 220 according to the present invention. Fig. 6 is an enlarged view illustrating an embodiment of the area AA shown in fig. 5.

Referring to fig. 4, the upper layer 200 may include an adhesive layer 210, a window 220, and a functional coating layer 230 sequentially stacked along the third direction DR 3. The adhesive layer 210 may constitute the lower surface 200-B of the upper layer 200 and the functional coating 230 may constitute the upper surface 200-U of the upper layer 200.

Fig. 4 shows only an example of constituting the upper layer 200, and the components constituting the upper layer 200 are not limited to the above example. In an embodiment, the upper layer 200 may, for example, only comprise at least some of the components described above. In alternative embodiments, the upper layer 200 may also include other layers in addition to the components described above. Further, the stacking order of the components constituting the upper layer 200 is not limited to the example shown in fig. 4.

The adhesive layer 210 may comprise a conventional adhesive or glue. In an embodiment, the adhesive layer 210 may be, for example, a transparent adhesive member such as a pressure sensitive adhesive film ("PSA"), an optically clear adhesive film ("OCA"), or an optically clear resin ("OCR").

The adhesive layer 210 may be disposed on the display module 100 (refer to fig. 2). The upper layer 200 may be attached to the display module 100 (refer to fig. 2) by an adhesive layer 210.

The window 220 may be disposed on the adhesive layer 210. In an embodiment, the window 220 may be in the form of a window layer. The window 220 may include a lower surface 220-B and an upper surface 220-U, the lower surface 220-B facing the adhesive layer 210, the upper surface 220-U spaced apart from the adhesive layer 210, and the lower surface 220-B interposed between the upper surface 220-U and the adhesive layer 210.

A first non-fold region 200NF1, a fold region 200F, and a second non-fold region 200NF2 may be defined in window 220 along first direction DR 1. That is, the fold region 200F may be defined between the first 200NF1 and second 200NF2 non-fold regions. Each of the first, folded, and second unfolded regions 200NF1, 200F, and 200NF2 of the window 220 may correspond to each of the first, folded, and second unfolded regions 1000NF1, 1000F, and 1000NF2 of the display apparatus 1000 (refer to fig. 1).

Referring to fig. 5, the window 220 may include a base layer BS and a resin RS. Although not separately shown, the window 220 may further include a light blocking pattern (not shown). Referring to fig. 6, the window 220 may include a base layer BS and a resin RS disposed in a plurality of grooves HM defined in the base layer BS.

The base layer BS may be tempered glass. When the tempered glass is applied to the window 220, the tempered glass has strong scratch resistance to improve impact resistance of the display device 1000 (refer to fig. 1A) compared to the polyimide film.

The thickness of the window 220 is the same as the thickness of the base layer BS. In embodiments, the thickness of the foundation layer BS may be, for example, about 100 μm to about 500 μm, and preferably may be about 100 μm to about 400 μm.

The resin RS may be disposed in each of the grooves HM. In an embodiment, each of the grooves HM may include a first portion PT1 having a circular shape, a second portion PT2 having a circular shape and spaced apart from the first portion PT1, and a third portion PT3 connecting the first portion PT1 and the second portion PT 2. The shape of the third portion PT3 is not limited. A detailed description about the resin RS will be described later.

Fig. 7 is a plan view of a base layer BS according to the present invention. Fig. 8A is an enlarged view illustrating an embodiment of the area AA' shown in fig. 7. Fig. 8B is an enlarged view illustrating an embodiment of the area AA' shown in fig. 7. Fig. 8B illustrates an area AA ″ as an embodiment of the area AA' illustrated in fig. 7.

Referring to fig. 7, a first non-folding region 220NF1, a folding region 220F, and a second non-folding region 220NF2 may be sequentially defined in a base layer BS along a first direction DR 1. That is, the fold region 220F may be defined between the first non-fold region 220NF1 and the second non-fold region 220NF 2. The folding area 200F and the non-folding areas 200NF1 and 200NF2 (refer to fig. 4) of the window 220 may correspond to the folding area 220F and the non-folding areas 220NF1 and 220NF2 of the base layer BS.

The base layer BS may overlap the folding area 220F and may be folded along a folding axis defined in the upper surface 220-U (refer to fig. 4) or the lower surface 220-B (refer to fig. 4) of the base layer BS.

Referring to fig. 1A and 7 together, the base layer BS may be folded like the display apparatus 1000. Each of the first, folding, and second non-folding regions 220NF1, 220F, and 220NF2 of the base layer BS may correspond to each of the first, folding, and second non-folding regions 1000NF1, 1000F, and 1000NF2 of the display device 1000.

To improve the folding properties of the window 220, a plurality of grooves HM may be defined in the folding area 220F of the base layer BS.

Fig. 8A shows the numerical value of the groove HM. The length H1 indicates a value obtained by measuring the length of each of the grooves HM in the second direction DR 2. The length H2 indicates a value obtained by measuring the lengths of the grooves HM overlapping each other in the first direction DR 1. The length L1 indicates the distance the grooves HM are spaced apart in the first direction DR 1. The length L2 indicates the distance by which the grooves HM are spaced apart in the second direction DR 2. The length DI indicates the diameter of the first portion PT1 of each of the grooves HM. The length WD indicates the width of the third portion PT3 of each of the grooves HM in the first direction DR 1.

The value of the groove HM may be adjusted according to the thickness of the base layer BS. In an embodiment, when the thickness of the base layer BS is about 500 micrometers (μm), the length H1 may be 2500 μm or more, for example. In embodiments, length H2 may be, for example, about 0.2 to about 0.6 times length H1. In embodiments, the diameter DI may be, for example, from about 150 μm to about 200 μm. In embodiments, width WD may be, for example, about 25 μm to about 30 μm. In an embodiment, length L1 may be, for example, about 250 μm to about 300 μm. In an embodiment, length L2 may be, for example, about 500 μm to about 550 μm. However, the present invention is not limited thereto. When the thickness of the base layer BS is changed, the values of the lengths H1, H2, DI, and WD may be changed in the same proportion as the rate of change in the thickness of the base layer BS.

In embodiments, when the thickness of the base layer BS is about 250 μm, the length H1 may be, for example, about 1250 μm or more. In embodiments, length H2 may be, for example, about 0.2 to about 0.6 times length H1. In embodiments, the diameter DI may be, for example, about 75 μm to about 100 μm. In embodiments, width WD may be, for example, from about 12.5 μm to about 15 μm. In an embodiment, length L1 may be, for example, about 125 μm to about 150 μm. In an embodiment, the length L2 may be, for example, about 250 μm to about 275 μm.

In an embodiment, when the thickness of the base layer BS is about 100 μm, the length H1 may be, for example, about 500 μm or more. In embodiments, length H2 may be, for example, about 0.2 to about 0.6 times length H1. In embodiments, the diameter DI may be, for example, from about 30 μm to about 40 μm. In embodiments, width WD may be, for example, about 5 μm to about 6 μm. In an embodiment, length L1 may be, for example, about 50 μm to about 60 μm. In an embodiment, length L2 may be, for example, about 100 μm to about 110 μm.

In an embodiment, the width of the folding area 220F may be maintained at, for example, 5 millimeters (mm) even when the thickness of the base layer BS is changed. The width of the fold region 220F indicates the length shown in fig. 8A measured along the first direction DR 1.

Referring to fig. 8B, to improve visibility of the display apparatus, the third portion PT3' may have a curved shape. In an embodiment, the third portion PT3' may have a wavy shape, for example. The optical interference phenomenon caused by the groove HM ' is prevented by the third portion PT3' having the curved shape, thereby improving the visibility of the folding area 220F defining the groove HM '. In addition, the same description as that described in fig. 5, 6, 7, and 8A may be applied to the groove HM'.

Fig. 9A and 9B are enlarged views illustrating an embodiment of the area AA illustrated in fig. 5. Fig. 9A and 9B illustrate an area AA' ″ as an embodiment of the area AA illustrated in fig. 5.

In an embodiment, when a compressive force is applied to the window 220 (refer to fig. 5) as illustrated in fig. 9A, the third portion PT3 of the groove HM may have the first width W1. The resin RS disposed in the groove HM may absorb the compressive force applied to the window 220.

In an embodiment, when a tensile force is applied to the window 220 (refer to fig. 5) as shown in fig. 9B, the third portion PT3 "of the groove HM" has a first width W1 and a second width W2. The second width W2 may be a width measured at the center of the third portion PT3 ". First width W1 may be the width of the end of third portion PT3 "adjacent to first portion PT1 or second portion PT 2. The first width W1 is substantially the same as the first width W1 of the third portion PT3 shown in fig. 9A. In an embodiment, the second width W2 is greater than the first width W1. That is, the width of the third portion PT3 "may become smaller from the center of the third portion PT 3" toward the first portion PT1 and the second portion PT 2. The resin RS disposed in the groove HM "may absorb the tensile force applied to the window 220.

Referring to fig. 9A and 9B, when the resin RS having an elastic force is disposed in the groove HM, the window 220 may secure a flow space by a difference (W2-W1) in value between the second width W2 and the first width W1. In addition, the flow space may be ensured by adjusting the number of the grooves HM. In the display apparatus 1000 in the embodiment, a flow space in the window 220 may be secured by the plurality of grooves HM defined in the window 220 and the resin RS disposed in the plurality of grooves HM, thereby preventing the window 220 from being deformed by a compressive force or a tensile force generated when the display apparatus 1000 is folded.

Fig. 10 is an enlarged plan view illustrating an embodiment of a portion of a base layer BS according to the present invention. Fig. 11 schematically shows an embodiment of the resin RS according to the present invention.

Fig. 10 shows an enlarged folding area 220F of the base layer BS (refer to fig. 7). The first peripheral region NCA1, the central region CA, and the second peripheral region NCA2 may be sequentially defined in the fold region 220F along the first direction DR 1. That is, the central region CA may be defined between the first peripheral region NCA1 and the second peripheral region NCA 2.

The central area CA is a central portion of the folding area 220F, and may be an area of the folding area 220F that defines the folding axis FX of the foundation layer BS. The base layer BS may be folded in or out along a folding axis FX.

The first and second peripheral regions NCA1 and NCA2 may be regions between the central region CA and the first and second unfolded regions 220NF1 and 220NF2 (refer to fig. 7), respectively.

As shown in fig. 10, in an embodiment, a first groove HM1 defined in the central area CA and second and third grooves HM2 and HM3 defined in the first peripheral area NCA1 may be defined in the base layer BS. The second groove HM2 may be adjacent to the central area CA, and the third groove HM3 may be adjacent to the first non-folded area 220NF1 (refer to fig. 7). That is, the second groove HM2 may be defined between the first groove HM1 and the third groove HM 3.

Since the central area CA has a greater stress than the peripheral area NCA due to the folding, the length of the first gap P1 may be smaller than the length of the second gap P2 along the first direction DR1, wherein the first gap P1 is a gap between the first groove HM1 and the second groove HM2, and the second gap P2 is a gap between the second groove HM2 and the third groove HM 3. That is, the length of the gap between the grooves HM disposed in the central area CA may be smaller than the length of the gap between the grooves HM disposed in the peripheral area NCA. As the length of the gap between the grooves HM increases from the central area CA to the peripheral area NCA, the visibility of the display apparatus 1000 may be improved. The present invention is not limited thereto. In one embodiment, the length of the first gap P1 may be equal to the length of the second gap P2.

Fig. 11 schematically shows an embodiment of the resin RS according to the present invention. In an embodiment, the resin RS comprises or consists of a polymer, which comprises thiol groups (-SH).

Referring to fig. 6, 7 and 11 together, the resin RS fills each of the grooves HM defined in the folding area 220F of the base layer BS.

Since the resin RS is disposed in the folding region 220F (refer to fig. 7), the resin RS of the present invention can be selected within a range satisfying the folding and translucent properties of the window 220 (refer to fig. 5).

The resin RS may have a predetermined elastic force in order to satisfy the folding property of the window 220. In an embodiment, the resin RS may be an elastomer. Specifically, the resin RS may be, for example, a polydimethylsiloxane ("PDMS") based material. When the window 220 is folded, the PDMS based resin RS may absorb the applied compressive stress or tensile stress.

Since the resin RS disposed in the folding region 220F has a predetermined elastic force, the resin RS can absorb stress caused by folding to prevent the window 220 from being deformed. Accordingly, the occurrence of creases caused when the window 220 is folded a plurality of times can be reduced.

The resin RS may be a translucent material. To improve the translucent property of the window 220 including two or more materials, the difference between the refractive index of the resin RS and the refractive index of the base layer BS may be less than 0.1, for example. Preferably, the refractive index of the resin RS and the refractive index of the foundation layer BS may be adjusted to be substantially the same.

In an embodiment, when the foundation layer BS is a glass substrate, the refractive index of the resin RS may be, for example, about 1.5 to about 1.6. Specifically, the refractive index of the resin RS may be, for example, about 1.5 to about 1.54. To obtain a refractive index of 1.5 or more, the resin RS may include or consist of thiol groups (-SH).

The resin RS in the embodiment of the present invention may include polydimethylsiloxane thiol to satisfy folding and translucent properties. In embodiments, the polydimethylsiloxane thiol is an elastomer and may, for example, have a refractive index of about 1.5 to about 1.54.

Further, the level of crosslinking can be controlled by polymerizing a crosslinking agent with the resin RS for fine adjustment of the refractive index and elastic modulus. In embodiments, the resin RS including polydimethylsiloxane thiol and the crosslinker may be polymerized to increase thiol-ene crosslinking. The crosslinking agent may include at least one of a thiol-based crosslinking agent, a vinyl-based crosslinking agent, and an acrylic-based crosslinking agent. In embodiments, the thiol-based crosslinker may include, for example, pentaerythritol tetra-3-mercaptopropionate ("PETMP"), the vinyl-based crosslinker may include alpha, omega vinyl terminated PDMS, and the acrylic-based crosslinker may include pentaerythritol tetraacrylate, and the like.

In the window 220 in the embodiment of the invention, since the groove HM is defined in the folding area 220F of the base layer BS and the resin RS including the thiol group is disposed in each of the grooves HM, both folding and visibility properties can be improved. Accordingly, product reliability of the display device 1000 (refer to fig. 1A) including the window 220 of the embodiment may be improved.

In the embodiment of the present invention, the folding property of the display device may be improved by the plurality of grooves provided in the window and the resin provided in each of the plurality of grooves. Further, by adjusting the resin properties, the plurality of grooves may not be seen from the outside.

Although the present invention has been described with reference to preferred embodiments thereof, it is to be understood that the present invention should not be limited to these preferred embodiments but various changes and modifications can be made by one skilled in the art without departing from the spirit and scope of the present invention. Therefore, the technical scope of the present invention is not intended to be limited to what is set forth in the detailed description of the specification.