WO2020062560A1 - Polarizing structure and display device - Google Patents

Abstract

The present application relates to a polarizing structure and a display device. The polarizing structure comprises a phase compensation film, a polarization film, a support film and an anti-reflection film that are stacked in sequence, wherein the support film is provided with a plurality of grooves; the anti-reflection film is provided with a plurality of protruding structures matching the grooves, and each protruding structure is accommodated inside the corresponding groove; and the width of each protruding structure is less than or close to the wave length of incident light, and the refractive index of the support film is greater than the refractive index of the anti-reflection film.

Description

Polarizing structure and display device

Related applications

This application claims priority from a Chinese patent application filed with the Chinese Patent Office on September 30, 2018, with an application number of 201811162021.8 and an application name of "Polarized Structure and Display Device", the entire contents of which are incorporated herein by reference.

Technical field

The present application relates to the field of display, and in particular to a polarizing structure and a display device.

Background technique

The statements herein merely provide background information related to the present application and do not necessarily constitute prior art.

With the development of display technology, display devices have been widely used in such electronic products due to their advantages such as high picture quality, power saving, and thin body. Among them, the quality of the picture is the most important factor affecting the consumer experience. . The display device is generally composed of a backlight module and a display panel placed on the backlight module. The backlight module provides incident light for the display panel. The incident light is usually concentrated and incident on the display panel. Therefore, when viewing the display screen in the frontal direction, It can obtain better display image quality, but when viewing the display screen in the side view direction, the image quality is poor and the color cast is more serious, which makes the viewing angle of normal display smaller.

Summary of the Invention

A polarizing structure is provided according to various embodiments of the present application.

A polarizing structure includes:

A phase compensation film having a light incident surface and a light exit surface opposite to the light incident surface;

A polarizing film provided on the light emitting surface of the phase compensation film;

A supporting film provided on the polarizing film, the supporting film having a first refractive index, a plurality of grooves formed on a side of the supporting film facing away from the polarizing film; and

The anti-reflection film is formed with a plurality of convex structures that match the shape and size of the groove. The width of each of the convex structures is smaller than or close to the wavelength of incident light, and the anti-reflection film is attached to the support. The anti-reflection film has a second refractive index, and the first refractive index is greater than the second refractive index.

Since in display devices, most of the light is incident perpendicularly to the polarizing structure, the polarizing structure includes a polarizing film and a support film stacked on the polarizing film to support the protection of the polarizing film and an anti-reflection film and anti-reflection on the supporting film. The film reduces glare and reflections and improves the visual experience. If the surface of each layer of the polarizing structure is flat and perpendicular to the normal incident light, most of the incident light is emitted perpendicularly when it is incident on the polarizing structure vertically, and most of the light energy is concentrated in the positive viewing angle, which results in a better quality of the display panel's positive viewing angle. The quality of the side view is poor. In this solution, a groove is formed in the supporting film of the polarizing structure, and an anti-reflection film is stacked on the supporting film. The anti-reflection film is formed with a plurality of convex structures matching the groove, and the anti-reflection film is formed. It is in close contact with the support film and has no gap. Each raised structure is received in the corresponding groove. The support film has a first refractive index, the antireflection film has a second refractive index, and the first refractive index is greater than the second refractive index, that is, When light enters the display panel vertically, the process of penetrating the support film and entering the anti-reflection film is a process from light dense to photophobic. At the same time, a plurality of convex structures are formed on the side of the anti-reflection film that is in contact with the support film. The width of each convex structure is smaller than or close to the wavelength of the incident light. The rising structure is equivalent to a grating, and the light incident on the convex structure will be diffracted, thereby changing the propagation path of the light, dispersing the vertically incident light to the side viewing angle, and improving the image quality of the side viewing angle.

In one embodiment, a width of each of the protruding structures is greater than or equal to 300 nm and less than or equal to 1000 nm.

In one embodiment, each of the convex structures is an elongated convex structure, and the elongated convex structures are arranged side by side.

In one embodiment, each of the convex structures is arranged in a two-dimensional matrix array, and the length and width of each of the convex structures are both smaller than or close to the wavelength of incident light.

In one embodiment, the center-to-center distance between adjacent raised structures is less than or equal to 10 μm.

In one of the examples, the support film includes a triacetyl cellulose support film.

In one embodiment, the support film includes a polymethyl methacrylate support film.

In one embodiment, the support film includes a polyethylene terephthalate support film.

In one embodiment, the polarizing film is a polyvinyl alcohol film.

In one embodiment, the first refractive index is greater than 1.0 and less than 2.5.

In one embodiment, the second refractive index is greater than 1.0 and less than 2.5.

In one embodiment, the rough surface is a matte surface.

In one embodiment, the rough surface has a film stack formed of a low-refractive material and a high-refractive material alternately, and the film stack is configured to interfere with light to reduce reflected light.

In one of the embodiments, it further includes:

A pressure-sensitive adhesive layer is provided on the light incident surface of the phase compensation film.

In one embodiment, each of the raised structures is arranged periodically.

In one embodiment, a difference between the first refractive index and the second refractive index ranges from 0.01 to 1.5.

According to various embodiments of the present application, another polarizing structure is provided.

A polarizing structure includes:

A phase compensation film having a light incident surface and a light exit surface opposite to the light incident surface;

A polarizing film provided on the light emitting surface of the phase compensation film;

A supporting film provided on the polarizing film, the supporting film having a first refractive index, a plurality of grooves formed on a side of the supporting film facing away from the polarizing film; and

An anti-reflection film is formed with a plurality of convex structures that match the shape and size of the grooves. Each of the convex structures is arranged in a two-dimensional matrix array, and the length and width of each of the convex structures are less than or close to incident. The wavelength of light, the center distance between adjacent raised structures is less than or equal to the opening width of a single pixel, the anti-reflection film is attached to the support film, and each raised structure is received in a corresponding groove The anti-reflection film has a second refractive index, and the first refractive index is greater than the second refractive index.

The above-mentioned polarizing structure includes at least one convex structure in each pixel interval, which can deflect most of the light incident perpendicularly to the display panel to a side viewing angle in a two-dimensional plane, and distributes positive viewing angle energy to the side viewing angle, thereby improving the side viewing angle. Quality.

A display device is provided according to various embodiments of the present application.

A display device includes:

A backlight module configured to provide a light source; and

A display panel is placed on one side of the backlight module and is set as a display screen;

The display panel includes a polarizing structure, and the polarizing structure includes:

A phase compensation film having a light incident surface and a light exit surface opposite to the light incident surface;

A polarizing film provided on the light emitting surface of the phase compensation film;

A supporting film provided on the polarizing film, the supporting film having a first refractive index, a plurality of grooves formed on a side of the supporting film facing away from the polarizing film; and

The anti-reflection film is formed with a plurality of convex structures that match the shape and size of the groove. The width of each of the convex structures is smaller than or close to the wavelength of incident light, and the anti-reflection film is attached to the support. The anti-reflection film has a second refractive index, and the first refractive index is greater than the second refractive index.

The display panel of the above display device includes a polarizing structure, which can deflect the light perpendicularly incident on the display panel to the side viewing angle and distribute the energy of the positive viewing angle to the side viewing angle, thereby improving the image quality of the side viewing angle.

In one embodiment, the display panel is a liquid crystal display panel.

In one embodiment, an included angle between a divergence direction of the incident light generated by the backlight module and a direction perpendicular to the display panel is less than 30 °.

Details of one or more embodiments of the present application are set forth in the accompanying drawings and description below. Other features, objects, and advantages of the application will become apparent from the description, the drawings, and the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to better describe and illustrate embodiments and / or examples of those inventions disclosed herein, reference may be made to one or more drawings. The additional details or examples used to describe the drawings should not be considered as limiting the scope of any of the disclosed inventions, the presently described embodiments and / or examples, and the best mode of these inventions as currently understood.

Figure 1 is an exploded view of a polarized structure;

2 is a schematic diagram of diffraction of incident light by a polarizing structure;

3a is a perspective structural view of an anti-reflection film in an embodiment;

3b is a schematic perspective view of an anti-reflection film in another embodiment;

4 is a partial cross-sectional view of a polarizing structure in an embodiment;

5 is a schematic view of a polarized light structure in an embodiment;

6 is a schematic structural diagram of a display device according to an embodiment;

FIG. 7 is a schematic structural diagram of a display panel according to an embodiment.

detailed description

In order to facilitate understanding of the present application, the present application will be described more fully with reference to the related drawings. Preferred embodiments of the present application are shown in the drawings. However, this application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the specification of the present application is only for the purpose of describing specific embodiments, and is not intended to limit the present application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

In order to thoroughly understand the present application, detailed steps and structures will be provided in the following description in order to explain the technical solution proposed in the present application. The preferred embodiments of the present application are described in detail below. However, in addition to these detailed descriptions, the present application may have other implementations.

In an embodiment, as shown in FIG. 1, the polarizing structure includes a phase compensation film 100, a polarizing film 200, a support film 300, and an anti-reflection film 400 stacked in this order. The phase compensation film 100 has a light incident surface 100A and a light output. The surface 100B and the light incident surface 100A are surfaces that receive incident light. The light enters the phase compensation film 100 from the light incident surface 100A, and is phase-compensated by the phase compensation film 100 and is emitted from the light emitting surface 100B. In the display, the phase delay phenomenon occurs after the light is processed. The phase delay will seriously affect the image quality. The phase compensation film 100 is provided to perform phase compensation before the light exits the display panel, which can avoid the effect of phase delay on the image quality. In one embodiment, the phase compensation film 100 may be an A-plate or a C-plate or a combination of an A-plate and a C-plate. The phase-compensated light passes through the polarizing film 200, and the polarizing film 200 polarizes the incident light. Only the light whose electric field direction is parallel to the polarization axis of the polarizing film 200 can penetrate the polarizing film 200, that is, the light emitted from the polarizing film 200. The direction of the electric field is parallel to the transmission axis of the polarizing film 200. In one embodiment, the polarizing film 200 is a polyvinyl alcohol film. The polyvinyl alcohol film has high transparency, high elongation performance, and has a polarizing effect on light. Since the polarizing film 200 has extremely strong hydrophilicity, a support film 300 needs to be provided on the surface of the polarizing film 200 to support and protect the physical characteristics of the polarizing film 200. In one embodiment, the support film 300 may include a triacetate cellulose (TAC) support film, may also include a polyethylene terephthalate (PET) support film, and may further include polymethyl methacrylate (PMMA ) Supporting film. In this solution, a plurality of grooves 301 are formed on a side of the support film 300 facing away from the polarizing film 200, and a side of the grooves of the support film 300 is covered with an anti-reflection film 400. The convex structures 401 matching the shape and size of the grooves 301, each of the convex structures 401 can be just embedded in the corresponding grooves 301, the width of each of the convex structures 401 is smaller than or close to the wavelength of the incident light, and the antireflection film 400 is attached On the supporting film 300, each protruding structure 401 is completely contained in the corresponding groove 301, that is, the supporting film 300 and the anti-reflection film 400 are closely adhered without a gap. The supporting film 300 has a first refractive index n1, and the antireflection film 400 has a second refractive index n2. The first refractive index n1 is larger than the second refractive index n2. When light penetrates the supporting film 300 and enters the antireflection film 400, The process of dense into photophosgene. Because the width of each convex structure 401 is smaller than or close to the wavelength of incident light, when the incident light propagates to the convex structure 401, because the width of each convex structure 401 is smaller than or close to the wavelength, the convex structure 401 is equivalent to A grating, where light can be diffracted at the raised structure 401.

In the display device, since most of the light is incident into the polarized structure vertically, that is, most of the light is perpendicular to the light incident surface 100A, this solution adopts a support film 300 and an anti-reflection film 400 with different refractive indexes and anti-reflection. A convex structure 401 is formed on the side of the film 400 that is in contact with the support film 300. A grating is formed by the convex structure 401. When incident light enters the anti-reflection film 400 from the support film 300 vertically, diffraction occurs at the convex structure 401 and changes. The propagation path of the vertically incident light deflects the light, so that the light energy of the positive viewing angle is distributed to the large viewing angle, and the image quality of the side viewing angle is improved.

In one embodiment, the anti-reflection film 400 may be a film having a rough surface, which is located on the side of the anti-radiation film 400 facing away from the convex structure 401. The surface of the film can be made reflective by performing a slight uneven process. It becomes a matte non-reflective surface, so that the light reflectivity can be reduced to less than 1%, preventing light from being emitted into the eyes, thereby reducing glare and reflection, and improving the display effect of the display. In another embodiment, the surface of the anti-reflection film 400 includes a film stack formed of low-refractive index and high-refractive index materials. The film stack interferes with light, and the reflected light is reduced by using the interference phenomenon, and its surface reflectance can be reduced. To 0.5% or less.

As shown in FIG. 2, the width of each convex structure 401 is X, and the value of X may be 300 nm ≦ X ≦ 1000 nm. When light penetrates the support film 300 and enters the anti-reflection film 400 vertically, the convex structures 401 Diffraction occurs, that is, the light propagation path changes, and the light deviates from the original perpendicular incidence direction and diverges to the side. Therefore, more light enters the side and improves the image quality of the side viewing angle. It can be understood that the larger the difference between the first refractive index n1 and the second refractive index n2 is, the more obvious the diffraction phenomenon is, and the easier it is to distribute the frontal light type energy to a large viewing angle. In one embodiment, the value range of the first refractive index n1 is 1.0 <n1 <2.5, and the value range of the second refractive index n2 is 1.0 <n2 <2.5. In one embodiment, if m = n1-n2, the value range of m can be 0.01 <m <1.5.

As shown in FIG. 3a, a plurality of convex structures 401 are formed on the anti-reflection film 400. Each of the convex structures 401 is an elongated convex structure, and each of the elongated convex structures 401 can be arranged side by side. The width of the structure is smaller than or close to the wavelength of the incident light. As shown in FIG. 3b, each convex structure 401 may also be arranged in a two-dimensional matrix array, and the width (X direction) and length (Y direction) of each convex structure 401 are both smaller than or close to the wavelength of incident light. Because in the display device, most of the light generated by the backlight module is concentrated and incident on the display panel vertically. If the surface of each layer of the polarizing structure is flat and perpendicular to the normal incident light, the normal incident light will not pass through the polarizing plate. Changing its propagation direction, that is, when the light is incident perpendicularly, it still emits vertically, causing the light to be concentrated at the front view angle, so that the display quality of the front view direction is better, and the side view angle is poor due to the weak light. In this solution, since a plurality of convex structures 401 are provided, each convex structure 401 can diffract normal incident light, and the light deviates from the original normal incident direction and diverges to the side, so more light enters the side Side to improve the quality of the side view angle. When the protruding structures 401 are elongated protrusions arranged side by side, diffraction occurs only in one dimension (X direction), so that light is scattered to both sides of the protruding structures 401; when the protruding structures 401 are two When the two-dimensional rectangular array is arranged, since the length and width of each convex structure 401 are smaller than or close to the wavelength of incident light, diffraction occurs in a two-dimensional plane (X direction and Y direction). In one embodiment, the convex structures 401 are periodically arranged, that is, the diffraction grating constructed by the convex structures 401 is periodically arranged, which is convenient for modulating light waves. In one embodiment, the center-to-center distance between adjacent convex structures 401 is less than or equal to 10 μm, that is, less than the opening width of a general pixel, that is, each pixel opening corresponds to at least one convex structure 401 that deflects the pixel light. In some embodiments, each convex structure 401 is a rectangular parallelepiped convex structure. In another embodiment, the upper surface 301A of the sidewall of the groove 301 on the support film 300 includes a curved surface. As shown in FIG. 4, the light (arrow in the figure) is diffracted by the convex structure 401 and refracted through the curved surface. Refraction occurs while diffracting, which facilitates the deflection of light. In other embodiments, each of the protruding structures 401 may also be a protruding structure of other forms, and the size of each protruding structure 401 can diffract incident light.

In an embodiment, as shown in FIG. 5, the polarizing structure further includes a pressure-sensitive adhesive layer 500, and the pressure-sensitive adhesive layer 500 is attached to the light incident surface 100A of the phase compensation film 100, that is, the polarizing structure is in order from the light entering direction to the light emitting direction. It includes a pressure-sensitive adhesive layer 500, a phase compensation film 100, a polarizing film 200, a support film 300, and an anti-reflection film 400.

The present invention also relates to a polarizing structure. As shown in FIG. 1 and FIG. 3b, the polarizing structure includes a phase compensation film 100, a polarizing film 200, a support film 300, and an anti-reflection film 400 stacked in this order. The phase compensation film 100 has A plurality of grooves 301 are formed on the light-incident surface 100A and the light-emitting surface 100B, the side of the support film 300 facing away from the polarizing film 200, and the anti-reflection film 400 is formed with a plurality of convex structures 401 that match the shape and size of the grooves 301. Each convex structure 401 can be just embedded in the corresponding groove 301. The supporting film 300 has a first refractive index n1, the antireflection film 400 has a second refractive index n2, and the first refractive index n1 is greater than the second refractive index n2. The structures 401 are arranged in a two-dimensional matrix array, and the length and width of each convex structure 401 are smaller than or close to the wavelength of incident light. When light penetrates the support film 300 and enters the anti-reflection film 400, it is a process from the light dense to the light dense. Because the length and width of each convex structure 401 are less than or close to the wavelength of incident light, when the incident light propagates to the convex structure 401, because the width of each convex structure 401 is less than or close to the wavelength, the convex structure 401 It is equivalent to a grating, and the light can be diffracted at the convex structure 401 to deflect the incident light to the side viewing angle. Since the convex structures 401 are arranged in a two-dimensional rectangular array, incident light can be deflected to a side viewing angle in a two-dimensional plane, thereby improving the image quality of each side viewing angle in a two-dimensional plane. The center-to-center distance between adjacent convex structures 401 is less than or equal to the opening width of a single pixel, that is, it is satisfied that each pixel opening corresponds to at least one convex structure 401 to deflect light from the pixel.

The present application also discloses a display device. As shown in FIG. 6, the display device includes a backlight module 2 and a display panel 1 disposed on one side of the backlight module 1, wherein the display panel 1 includes the above-mentioned polarizing structure. The backlight module 2 is configured to provide a light source, and the light source generates incident light, which is incident on the display panel 1 in a concentrated manner. The divergent direction of the incident light and the direction perpendicular to the display panel 1 are at a small angle, and the small angle θ may be less than 30 °. Most of the light received by the display panel 1 is normal incident light. Since the display panel 1 includes a polarized structure, a support film 300 and an anti-reflection film 400 exist in the polarized structure, and a side of the anti-reflection film 400 and the support film 300 is formed. The convex structures 401 can deflect the normal incident light by diffracting at each of the convex structures 401, thereby distributing the energy of the positive viewing angle to the side viewing angle and improving the image quality of the side viewing angle. Among them, the polarizing structure has been described above, and is not repeated here. The backlight module 2 includes a side-type light source 2A and a light guide plate 2B opposite to the side-type light source 2A. The upper and lower surfaces of the light guide plate 2B are provided with long V-shaped grooves, and the upper surface of the light guide plate 2B has a V-shaped groove. The length direction of the vertical direction and the length direction of the V-shaped groove on the lower surface are perpendicular to each other.

In an embodiment, as shown in FIG. 7, the display panel 1 is a liquid crystal display panel. The display panel 1 includes an upper polarizing plate 10, a lower polarizing plate 30, and a liquid crystal sandwiched between the upper polarizing plate 10 and the lower polarizing plate 30. The layer 20 and the liquid crystal layer 20 include a glass substrate and liquid crystal molecules interposed between the glass substrate. The incident light passes through the lower polarizing plate and becomes linearly polarized light. The liquid crystal layer 20 can reverse the polarization direction of the linearly polarized light and allow the linearly polarized light to pass through the upper polarizing plate to display a picture on the display panel. The upper polarizing plate 10 includes Polarizing structure introduced above. In other embodiments, the display panel may also be an organic light-emitting diode (OLED) display panel, a quantum dot light emitting diode (QLED) display panel, or a curved display panel, and the above-mentioned polarizing structure is included. Other display panels.

The technical features of the embodiments described above can be arbitrarily combined. In order to simplify the description, all possible combinations of the technical features in the above embodiments have not been described. However, as long as there is no contradiction in the combination of these technical features, It should be considered as the scope described in this specification.

The above-mentioned embodiments only express several implementation manners of the present application, and their descriptions are more specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be noted that, for those of ordinary skill in the art, without departing from the concept of the present application, several modifications and improvements can be made, which all belong to the protection scope of the present application. Therefore, the protection scope of this application patent shall be subject to the appended claims.

Claims (20)

A polarizing structure includes: A phase compensation film having a light incident surface and a light exit surface opposite to the light incident surface; A polarizing film provided on the light emitting surface of the phase compensation film; A supporting film provided on the polarizing film, the supporting film having a first refractive index, a plurality of grooves formed on a side of the supporting film facing away from the polarizing film; and The anti-reflection film is formed with a plurality of convex structures that match the shape and size of the groove. The width of each of the convex structures is smaller than or close to the wavelength of incident light, and the anti-reflection film is attached to the support. The anti-reflection film has a second refractive index, the first refractive index is greater than the second refractive index, and the anti-reflection film faces away from One side of the raised structure has a rough surface. The polarizing structure according to claim 1, wherein a width of each of the convex structures is greater than or equal to 300 nm and less than or equal to 1000 nm. The polarizing structure according to claim 1, wherein each of the convex structures is an elongated convex structure, and the elongated convex structures are arranged side by side. The polarizing structure according to claim 1, wherein each of the convex structures is arranged in a two-dimensional matrix array, and a length and a width of each of the convex structures are less than or close to a wavelength of incident light. The polarizing structure according to claim 1, wherein a center-to-center distance between adjacent convex structures is less than or equal to 10 μm. The polarizing structure according to claim 1, wherein the supporting film comprises a triacetate supporting film. The polarizing structure according to claim 1, wherein the support film comprises a polymethyl methacrylate support film. The polarizing structure according to claim 1, wherein the supporting film comprises a polyethylene terephthalate supporting film. The polarizing structure according to claim 1, wherein the polarizing film is a polyvinyl alcohol film. The polarizing structure according to claim 1, wherein the first refractive index is greater than 1.0 and less than 2.5. The polarizing structure according to claim 1, wherein the second refractive index is greater than 1.0 and less than 2.5. The polarizing structure according to claim 1, wherein the rough surface is a matte surface. The polarizing structure according to claim 1, wherein the rough surface has a film stack formed of a low-refractive material and a high-refractive material alternately, and the film stack is arranged to interfere with light to reduce reflected light. The polarizing structure according to claim 1, further comprising: A pressure-sensitive adhesive layer is provided on the light incident surface of the phase compensation film. The polarizing structure according to claim 1, wherein each of the convex structures is arranged periodically. The polarizing structure according to claim 1, wherein a difference between the first refractive index and the second refractive index ranges from 0.01 to 1.5. A polarizing structure includes: A phase compensation film having a light incident surface and a light exit surface opposite to the light incident surface; A polarizing film provided on the light emitting surface of the phase compensation film; A supporting film provided on the polarizing film, the supporting film having a first refractive index, a plurality of grooves formed on a side of the supporting film facing away from the polarizing film; and An anti-reflection film is formed with a plurality of convex structures that match the shape and size of the grooves. Each of the convex structures is arranged in a two-dimensional matrix array. The wavelength of light, the center distance between adjacent raised structures is less than or equal to the opening width of a single pixel, the anti-reflection film is attached to the support film, and each raised structure is received in a corresponding groove The anti-reflection film has a second refractive index, and the first refractive index is greater than the second refractive index. A display device includes: A backlight module configured to provide a light source; and A display panel is placed on one side of the backlight module and is set as a display screen; The display panel includes a polarizing structure, and the polarizing structure includes: A phase compensation film having a light incident surface and a light exit surface opposite to the light incident surface; A polarizing film provided on the light emitting surface of the phase compensation film; A supporting film provided on the polarizing film, the supporting film having a first refractive index, a plurality of grooves formed on a side of the supporting film facing away from the polarizing film; and The anti-reflection film is formed with a plurality of convex structures that match the shape and size of the groove. The width of each of the convex structures is smaller than or close to the wavelength of incident light. The anti-reflection film is attached to the support. The anti-reflection film has a second refractive index, and the first refractive index is greater than the second refractive index. The display device according to claim 18, wherein the display panel is a liquid crystal display panel. The display device according to claim 18, wherein an included angle between a divergence direction of the incident light generated by the backlight module and a direction perpendicular to the display panel is less than 30 °.

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