阅读说明：本技术 光学膜和显示装置 (Optical film and display device ) 是由 孙凌宇 陈秀云 梁菲 杜景军 侯婷琇 方立宇 钟鹏 马一鸿 黄文� 于 2019-11-06 设计创作，主要内容包括：本发明提供一种光学膜,包括基体膜和多个微光学单元；所述基体膜包括相对的第一主表面和第二主表面,多个所述微光学单元设置在所述基体膜的第一主表面上；所述微光学单元为设置在所述基体膜上的凸起,所述微光学单元与所述第一主表面接触的表面的面积大于所述微光学单元背离所述第一主表面的表面的面积。本发明还提供一种显示装置,所述显示装置显示画面时,亮度均匀,显示效果好。(The invention provides an optical film, comprising a substrate film and a plurality of micro-optical units; the base film comprises first and second opposite major surfaces, and a plurality of the micro-optical units are arranged on the first major surface of the base film; the micro-optical unit is a protrusion arranged on the substrate film, and the area of the surface of the micro-optical unit, which is in contact with the first main surface, is larger than the area of the surface of the micro-optical unit, which faces away from the first main surface. The invention also provides a display device, and when the display device displays a picture, the brightness is uniform, and the display effect is good.)

1. An optical film comprising a substrate film and a plurality of micro-optical units;

the base film comprises first and second opposite major surfaces, and a plurality of the micro-optical units are arranged on the first major surface of the base film;

the micro-optical unit is a protrusion arranged on the substrate film, and the area of the surface of the micro-optical unit, which is in contact with the first main surface, is larger than the area of the surface of the micro-optical unit, which faces away from the first main surface.

2. The optical film of claim 1, wherein the micro-optical unit is in the shape of a trapezoidal hexahedron.

3. The optical film of claim 2, wherein the side of the micro-optical unit is angled between 45 ° and 65 ° from the first major surface.

4. The optical film of claim 3, wherein the surface of the micro-optical unit in contact with the substrate film is a first rectangle having a side length of between 20 and 25 microns, and the surface of the micro-optical unit facing away from the substrate film is a second rectangle having a side length of between 10 and 20 microns.

5. The optical film of claim 4, wherein the height of the micro-optical units is between 10 and 15 microns.

6. The optical film of claim 1, wherein the micro-optical elements are curved edges having a rectangular or trapezoidal cross-section along a plane perpendicular to the first major surface.

7. The optical film according to claim 1, wherein the number of the micro-optical units provided per unit area on the first main surface gradually increases in a predetermined direction.

8. The optical film of claim 1, wherein the micro-optical units are of unitary construction with the substrate film.

9. The optical film of claim 1, wherein the centers of the surfaces of any N micro-optical units in contact with the first major surface are not collinear, wherein 2 < N ≦ 5.

10. A display device comprising a light source, a light guide plate and a display panel, wherein the display device further comprises the optical film according to any one of claims 1 to 9;

the light guide plate comprises a light incident surface facing the light source, a first light transmitting surface connected with the light incident surface and a second light transmitting surface connected with the light incident surface, and the first light transmitting surface and the second light transmitting surface are arranged oppositely;

the optical film is arranged between the first light-transmitting surface and the display surface of the display panel, and the micro-optical unit is far away from the display surface.

11. The display device according to claim 10, wherein a plurality of scattering units are formed on the first light-transmitting surface and/or the second light-transmitting surface.

12. The front-light source of claim 10, wherein the angle between the light incident surface and the thickness direction of the light guide plate is between 3 ° and 7 °.

13. The display device according to claim 10, wherein the refractive index of the micro-optical unit is the same as that of the light guide plate.

Technical Field

The present invention relates to the field of display devices, and in particular, to an optical film and a display device including the same.

Background

The reflective display device can utilize ambient light around as an illumination source to display a picture, and compared with the conventional transmissive display device, the reflective display device has the advantages of soft light, power saving, better display effect outdoors and the like, and is more and more concerned.

In the practical application process of the reflective display device, the brightness of the reflective display device is low and the display effect is poor under the environment with weak ambient light or in a dark room.

In order to solve the above problem, a front light source may be added to the reflective display device to assist the reflective display device in displaying. Specifically, as shown in fig. 1, the display device includes a front light 100 and a reflective display panel 200, the front light 100 including a light source 110 and a light guide plate 120, the light guide plate 120 being disposed on a display side of the reflective display panel 200.

Although the arrangement of the front light source can improve the display brightness, the arrangement of the front light source also brings about the problem of uneven picture brightness.

Disclosure of Invention

An object of the present invention is to provide an optical film and a display device including the same. The display device has uniform brightness of the display picture.

In order to achieve the above object, as one aspect of the present invention, there is provided an optical film including a base film and a plurality of micro optical units;

the base film comprises first and second opposite major surfaces, and a plurality of the micro-optical units are arranged on the first major surface of the base film;

the micro-optical unit is a protrusion arranged on the substrate film, and the area of the surface of the micro-optical unit, which is in contact with the first main surface, is larger than the area of the surface of the micro-optical unit, which faces away from the first main surface.

Optionally, the micro-optical unit is shaped as a trapezoidal hexahedron.

Optionally, an angle between a side face of the micro-optical unit and a surface of the micro-optical unit in contact with the first major surface is between 45 ° and 65 °.

Optionally, a surface of the micro-optical unit in contact with the substrate film is a first rectangle with a side length between 20 micrometers and 25 micrometers, and a surface of the micro-optical unit facing away from the substrate film is a second rectangle with a side length between 10 micrometers and 20 micrometers.

Optionally, the height of the micro-optical unit is between 10 and 15 microns.

Optionally, the micro-optical element is a curved edge having a rectangular cross-section along a plane parallel to the first major surface.

Optionally, the number of micro-optical units provided per unit area on the first major surface gradually increases in a predetermined direction.

Optionally, the micro-optical unit is of unitary construction with the substrate film.

Optionally, the centers of the surfaces of any N micro-optical units in contact with the first main surface are not on the same straight line, wherein N is more than 2 and less than or equal to 5.

As a second aspect of the present disclosure, a display device is provided, including a light source, a light guide plate, and a display panel, where the display device further includes the optical film provided in the first aspect of the present disclosure, the light guide plate includes a light incident surface facing the light source, a first light transmitting surface connected to the light incident surface, and a second light transmitting surface connected to the light incident surface, the first light transmitting surface and the second light transmitting surface are disposed opposite to each other, the optical film is disposed between the first light transmitting surface and the display surface of the display panel, and the micro optical unit is far away from the display surface.

Optionally, a plurality of scattering units are formed on the first light-transmitting surface and/or the second light-transmitting surface.

Optionally, an included angle between the light incident surface and the thickness direction of the light guide plate is 3 ° to 7 °.

Optionally, the micro-optical unit has a refractive index equal to a refractive index of the light guide plate.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention and not to limit the invention. In the drawings:

fig. 1 is a schematic structural view of a display device having a front light source in the related art;

FIG. 2 is a schematic structural diagram of an optical film provided by the present invention;

FIG. 3 is a schematic diagram of one embodiment of a display device provided by the present invention;

FIG. 4 is a schematic diagram illustrating total reflection of light in a light guide plate according to the related art;

FIG. 5 is a schematic representation of the propagation of light in the same direction of propagation as the light rays shown in FIG. 4 in an optical film provided by the present disclosure;

FIG. 6 is a schematic perspective view of an embodiment of a micro-optical unit;

FIG. 7 is a schematic diagram in longitudinal section of a micro-optical unit;

FIG. 8 is a schematic diagram showing the distribution density of micro-optical elements in an optical film;

FIG. 9 is a schematic view of another embodiment of an optical film;

fig. 10 is a schematic view of the structure of a front light in a display device.

Detailed Description

The following detailed description of embodiments of the invention refers to the accompanying drawings. It should be understood that the detailed description and specific examples, while indicating the present invention, are given by way of illustration and explanation only, not limitation.

The terms "upper" and "lower" as used herein refer to the directions "upper" and "lower" in fig. 2.

As one aspect of the present invention, as shown in fig. 2, there is provided an optical film 300, the auxiliary optical film 300 including a base film 310 and a plurality of micro-optical units 320.

The base film 310 includes first and second main surfaces a and B disposed opposite to each other, and the plurality of micro-optical units 320 are disposed on the first main surface a of the base film 310.

The micro optical unit 320 is a projection provided on the base film 310, and an area of a surface (which may be referred to as a bottom surface for convenience of description) of the micro optical unit 320 in contact with the first main surface a is larger than an area of a surface (which may be referred to as a top surface for convenience of description) of the micro optical unit 320 facing away from the first main surface. In other words, the micro optical unit 320 has a structure that is narrow at the top and wide at the bottom.

The optical film 300 provided by the present invention is applied to a display device having a front light source, and specifically, as shown in fig. 3, the display device includes a front light source 100, a display panel 200, and an optical film 300, and the optical film 300 is disposed between a light guide plate 120 of the front light source 100 and a display surface of the display panel 200.

The light source 110 of the front light source 100 emits light toward the light incident surface of the light guide plate 120, and external ambient light also enters the light guide plate 120. After entering the light guide plate 120, the light propagates inside the light guide plate 120.

Note that, in the case where the optical film 300 is not provided, as shown in fig. 4, part of the light may be totally reflected at the interface of the light guide plate 120 and return to the inside of the light guide plate 120 again without entering the display panel 200.

In the optical film 300 provided by the present invention, the refractive index of the micro-optical unit 320 is similar to the refractive index of the light guide plate, and when the optical film 300 provided by the present invention is disposed in the display device, as shown in fig. 5, light that would originally undergo total reflection enters the micro-optical unit 320 of the optical film, and exits from the side surface of the micro-optical unit 320 (or transmits the micro-optical unit 320), and irradiates on the side surface of the adjacent micro-optical unit 320. The light irradiated on the side surface of the micro-optical unit 320 may be reflected by the side surface of the micro-optical unit 320, and after several reflections of the light guide plate 120, the peripheral micro-optical units 320, etc., the light that would be totally reflected back to the light guide plate is finally incident on the display panel 200.

Of course, light impinging on the side of the micro-optical unit 320 may also enter the interior of the micro-optical unit 320, and the light passes down into the substrate film 310 and eventually into the display panel 200.

It can be seen that a part of the light that would otherwise be totally reflected enters the display panel 200, thereby increasing the total amount of light entering the display panel 200 and further improving the brightness of the display panel 200.

In addition, light directly emitted from a portion of the light guide plate 120 corresponding to the interval between the adjacent two micro optical units 320 may also be irradiated on the side of the micro optical unit 320. The part of light may directly enter the micro optical unit 320 and finally enter the display panel 200, or may be reflected multiple times between the side surface of the micro optical unit 320, the surface of the light guide plate 120, and the first main surface of the base film 310 to perform sufficient light mixing, so that the brightness of the light incident on the display panel 200 is more uniform, the display brightness of the display panel 200 is more uniform, and the display effect of the display panel 200 is improved.

In the embodiment shown in fig. 2, the side of the micro optical unit 320 is an inclined plane, but in the present invention, the shape of the side of the micro optical unit 320 is not limited thereto. For example, the side surface of the micro-optical unit may be any one of an inclined plane, a concave curved surface and a convex curved surface, or the side surface of the micro-optical surface may be a combination of the above surface shapes.

As a preferred embodiment, the micro optical unit 320 may be a trapezoidal hexahedron, as shown in fig. 6. The "trapezoidal hexahedron" as used herein refers to a hexahedron whose longitudinal section (i.e., a section perpendicular to the first major surface) is trapezoidal.

With the display panel 200 of the reflection type, when the angle of the incident light with the direction perpendicular to the display surface of the display panel 200 (in the specific case shown in fig. 3, the direction perpendicular to the display surface of the display panel 200 is the vertical direction) is between ± 30 °, a good display effect can be obtained.

The structure of the micro-optical unit on the combined structure of the optical film may be adjusted in order to make the angular distribution of the display incident light within a range of ± 30 ° as much as possible.

Repeated tests by the inventor of the present invention have found that, for light transmitted from the micro-optical unit 320, when an angle β (see fig. 7) between a side surface of the micro-optical unit 320 and a bottom surface of the micro-optical unit is 55 °, the light intensity symmetry axis is located at the center; when the included angle beta between the side surface of the micro optical unit 320 and the bottom surface of the micro optical unit is larger than 55 degrees, the light intensity symmetry axis is shifted towards the light source side, and when the included angle beta between the side surface of the micro optical unit 320 and the bottom surface of the micro optical unit is smaller than 55 degrees, the light intensity symmetry axis is shifted away from the light source side.

Therefore, in order to ensure that the light intensity axis emitted from the micro optical unit 320 is located at the middle position of the micro optical unit as much as possible, the angles between the side surfaces and the bottom surface of the micro optical unit 320 may be about 55 °. Of course, about 55 ° here may mean 45 ° to 65 °.

In order to ensure that the included angle β between the side surface of the micro-optical unit 320 and the bottom surface of the micro-optical unit 320 is about 55 °, optionally, the surface of the micro-optical unit 320 in contact with the substrate film 310 is a first rectangle with a side length of between 20 micrometers and 25 micrometers, and the surface of the micro-optical unit 320 facing away from the substrate film 310 is a second rectangle with a side length of between 10 micrometers and 20 micrometers.

Optionally, the first rectangle and the second rectangle are both square.

Further, the height of the micro-optical unit 320 (i.e., the distance between the bottom surface of the micro-optical unit 320 and the top surface of the micro-optical unit 320) is between 10 micrometers and 15 micrometers.

Alternatively, the first rectangle may be a square having a side of 23 μm, the second rectangle may be a square having a side of 17 μm, and the height of the micro optical unit may be 11.4 μm.

In the present disclosure, the micro-optical units 320 may be randomly distributed on the surface of the base film 310 facing away from the reflective display panel 200. Here, "random" means that the centers of the surfaces of the micro-optical units 320 in contact with the first main surface are not arranged in a regular matrix. That is, the centers of the surfaces of any N micro-optical units in contact with the first main surface are not on the same straight line, wherein N is more than 2 and less than or equal to 5.

Of course, the invention is not limited thereto, and the micro-optical unit may also be a curved edge, as shown in fig. 9. For ease of manufacture, the curved edge is rectangular in cross-section in a plane perpendicular to the first major surface, and the surface of the curved edge in contact with the first major surface is a curved strip. It should be noted that fig. 9 only exemplarily shows the micro-optical units 320 on the auxiliary optical film 300, and does not mean that the auxiliary optical film 300 is provided with only 3 curved ribs.

In order to make the brightness of light emitted from the base film 310 of the optical film 300 more uniform, it is preferable that the number of the micro optical units provided per unit area on the first main surface is gradually increased in a predetermined direction.

When the optical film 320 is applied to a display device and is combined with a front light source, the predetermined direction is a direction away from the light source, i.e., a direction from left to right in fig. 2 and 8. In fig. 8, the density of the micro-optical units 320 disposed at the lower left corner of the optical film 300 is less than the density of the micro-optical units 320 disposed at the lower right corner of the optical film 300.

In the present invention, how to form the optical film 300 having the base film 310 and the micro-optical unit 320 is not particularly limited. As an alternative embodiment, the optical film 300 may be formed by an integral molding method, and the substrate film 310 and the micro-optical unit 320 are an integral structure. For example, the optical film 300 may be obtained by hot-pressing a film material, or the optical film 300 may be obtained by photolithography.

In the present invention, the specific material of the optical film 300 is not particularly limited, and for example, the optical film 300 may be made of polyethylene terephthalate (PET).

As a second aspect of the present invention, there is provided a display device, as shown in fig. 3, including a light source 110, a light guide plate 120, and a display panel 200. For convenience of description, the combined structure including the light source 110 and the light guide plate 120 may also be referred to as a front light 100.

As shown in fig. 10, the light guide plate 120 includes a light incident surface 123 facing the light source 110, a first light transmission surface 121 connected to the light incident surface 123, and a second light transmission surface 122 connected to the light incident surface 123, wherein the first light transmission surface 121 and the second light transmission surface 122 are disposed opposite to each other. The optical film 300 is disposed between the first light-transmitting surface 121 and the display surface of the display panel 200, and the micro-optical unit 320 of the optical film 300 is far away from the display surface of the display panel.

The light guide plate 120 functions to convert a point light source into a surface light source, and ambient light as well as light emitted from the front light source 100 can enter the display panel through the auxiliary optical film 100. The surface of the auxiliary optical film 100 facing the light guide plate 120 is the micro-optical unit 320, and the micro-optical unit 320 can fully mix incident light, so as to improve the uniformity of light entering the display panel, and further improve the uniformity of display brightness.

In order to improve the display brightness, preferably, a plurality of scattering units 122a are formed on the second light transmission surface 122 near the light incident surface 123.

By disposing the scattering unit 122a on the second light transmission surface 122, total reflection of light at the second light transmission surface 122 can be avoided, that is, the scattering unit 122a can be disposed to break the total reflection condition, so that more light can exit from the light guide plate 120, thereby improving the display brightness. Preferably, the scattering unit 112a may be disposed near the light incident surface 123.

As an alternative embodiment, the scattering unit 122a may be a groove recessed from the second light-transmitting surface 122. As an alternative, the depth of the groove may be around 1 mm. For example, the depth of the groove may be between 0.5mm and 1.5 mm.

Of course, the present invention is not limited to this, and a plurality of the scattering means may be provided on the first light transmission surface 121.

In the present invention, how to fixedly connect the optical film 300 to the display panel 200 is not particularly limited, and as shown in fig. 3, the base film 310 of the optical film 300 may be bonded to the display surface of the display panel 200 by using an optically transparent adhesive 400.

In the present disclosure, the structure of the light incident guide plate 120 is not particularly limited. For example, the light guide plate 120 may be a rectangular plate in which the light incident surface 123 is perpendicular to the first and second light transmission surfaces 121 and 122.

In order to further increase the amount of light emitted from the light guide plate 120, optionally, as shown in fig. 3, an angle α between the light incident surface 123 and the thickness direction of the light guide plate 120 is between 3 ° and 7 °. By setting the angle of the light incident surface 123, the light outgoing from the light guide plate can be distributed within ± 30 degrees as much as possible, so that the utilization rate of the light can be improved.

The refractive index of the light guide plate 120 may be the same as that of the micro-optical unit 320 of the optical film 300, so that the full emission condition may be better deteriorated.

As described above, the material of the optical film 300 may be PET, and then, the material of the light guide plate 120 may also be PET. Of course, the present invention is not limited thereto, and the material of the light guide plate 120 may be glass.

In the present invention, the specific type of the display panel 200 is not particularly limited. For example, the display panel 200 may be a reflective liquid crystal display panel.

Of course, the present invention is not limited thereto, and the display panel 200 may be any one of a transflective display, a transparent display, an ink display, and the like.

It will be understood that the above embodiments are merely exemplary embodiments taken to illustrate the principles of the present invention, which is not limited thereto. It will be apparent to those skilled in the art that various modifications and improvements can be made without departing from the spirit and substance of the invention, and these modifications and improvements are also considered to be within the scope of the invention.