Patent Publication Number: US-11029553-B2

Title: Optical composite film, display panel, and display device

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a U.S. National Stage application of, and claims priority to, PCT/CN2018/118460, filed Nov. 30, 2018, which further claims priority to Chinese Patent Application No. 201811277528.8, filed Oct. 30, 2018, the entire contents of which are incorporated herein in their entirety. 
     TECHNICAL FIELD 
     This application relates to the field of display technologies, and more particularly relates to an optical composite film, a display panel, and a display device. 
     BACKGROUND 
     Exemplary large-sized liquid crystal display (LCD) panels include a vertical alignment (VA) liquid crystal panel, an in-plane switching (IPS) liquid crystal panel, and the like. Compared with the IPS liquid crystal panel, the VA liquid crystal panel has advantage of relatively high production efficiency and low manufacturing costs, but has relatively obvious defects in optical properties. Particularly, a large-sized panel requires a relatively large viewing angle for presentation in commercial application, and at a large viewing angle, the brightness of the VA liquid crystal panel is rapidly saturated along with the voltage. As a result, the picture quality, the contrast, and the color shift at the viewing angle are deteriorated severely compared with the front picture quality, and a color shift problem is generated. 
     In addition, an architecture of an exemplary LCD display panel is usually a stacking structure. To be specific, polarizing plates are attached on and under a liquid crystal layer. However, a single-layered thickness of a current polarizing plate is approximately 200 and the upper and lower polarizing plates need to be 400 μm in total thickness. As a result, the liquid crystal display panel is relatively thick. 
     SUMMARY 
     This application provides an optical composite film that can improve color shift of a display panel at a large viewing angle and make the display panel relatively thin. 
     Moreover, a display panel and a display device are further provided. 
     An optical composite film comprises: 
     a first optically-uniaxial optical film layer, comprising a plate-shaped portion and a plurality of refraction portions disposed on a side of the plate-shaped portion, wherein the plurality of refraction portions is selected from one type of camber columns and quadrangular prisms, and when the plurality of refraction portions is the camber columns, the refraction portion has a plurality of side surfaces, one of the plurality of side surfaces is an arc-shaped convex surface, and a side surface of the refraction portion away from the arc-shaped convex surface is laminated to the plate-shaped portion; and when the plurality of refraction portions is the quadrangular prisms, a side surface of the refraction portion is laminated to the plate-shaped portion; 
     a second optically-uniaxial optical film layer, stacked on a side of the plate-shaped portion close to the refraction portion, wherein the plurality of refraction portions is accommodated in the second optically-uniaxial optical film layer, an extraordinary light refractive index of the first optically-uniaxial optical film layer is greater than an ordinary light refractive index of the second optically-uniaxial optical film layer, and a material of the first optically-uniaxial optical film layer is the same as a material of the second optically-uniaxial optical film layer; and 
     a reflection grating film layer, disposed on a side of the second optically-uniaxial optical film layer away from the first optically-uniaxial optical film layer. 
     In an embodiment, each of a material of the first optically-uniaxial optical film layer and a material of the second optically-uniaxial optical film layer is a nematic-phase liquid crystal molecule material. 
     In an embodiment, the extraordinary light refractive index of the first optically-uniaxial optical film layer is 1.0 to 2.5. 
     In an embodiment, the ordinary light refractive index of the second optically-uniaxial optical film layer is 1.0 to 2.5. 
     In an embodiment, a difference between the extraordinary light refractive index of the first optically-uniaxial optical film layer and the ordinary light refractive index of the second optically-uniaxial optical film layer is 0.01 to 2. 
     In an embodiment, the arc-shaped convex surface is a curved surface disposed when a circular arc line is moved along an extension direction of the refraction portion. 
     In an embodiment, the plurality of refraction portions is the camber columns, the plurality of refraction portions is arranged along a straight line, and extension directions of the plurality of refraction portions are parallel. 
     In an embodiment, the plurality of refraction portions is the camber columns, the plurality of refraction portions is arranged in a two-dimensional matrix, and two neighboring refraction portions are disposed at an interval. 
     In an embodiment, the plurality of refraction portions is the quadrangular prisms, the plurality of refraction portions is arranged along a straight line, extension directions of the plurality of refraction portions are parallel, and two neighboring refraction portions are disposed at an interval. 
     In an embodiment, the plurality of refraction portions is the quadrangular prisms, the plurality of refraction portions is arranged in a two-dimensional matrix, and two neighboring refraction portions are disposed at an interval. 
     In an embodiment, the reflection grating film layer comprises a transparent substrate and a plurality of strip-shaped metal layers disposed on the transparent substrate, and the plurality of metal layers is disposed at intervals and in parallel. 
     In an embodiment, the width of the metal layer is 50 nm to 150 nm, the thickness of the metal layer is 100 nm to 200 nm, and a spacing between two neighboring metal layers is 100 nm to 200 nm. 
     In an embodiment, the extraordinary light refractive index of the first optically-uniaxial optical film layer is 1.0 to 2.5, the ordinary light refractive index of the second optically-uniaxial optical film layer is 1.0 to 2.5, and a difference between the extraordinary light refractive index of the first optically-uniaxial optical film layer and the ordinary light refractive index of the second optically-uniaxial optical film layer is 0.01 to 2. 
     A display panel comprises the foregoing optical composite film, a first glass film layer, a first indium tin oxide film layer, a liquid crystal layer, a second indium tin oxide film layer, a metal grating film layer, a second glass film layer, and a photoresist layer, wherein the reflection grating film layer, the first glass film layer, the first indium tin oxide film layer, the liquid crystal layer, the second indium tin oxide film layer, the metal grating film layer, and the second glass film layer are sequentially stacked, and the photoresist layer is stacked between the metal grating film layer and the second glass film layer, or the photoresist layer is stacked between the first glass film layer and the first indium tin oxide film layer. 
     A display device comprises a backlight source and the foregoing display panel, wherein the backlight source is located on a side of the display panel. 
     Details of one or more embodiments of this application are provided in the following accompanying drawings and descriptions. Other features, objectives, and advantages of this application will become apparent from the specification, the accompanying drawings, and the claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic structural diagram of a display device according to an implementation; 
         FIG. 2  is a schematic structural diagram of a backlight source of the display device shown in  FIG. 1 ; 
         FIG. 3  is a schematic structural diagram of a display panel of the display device shown in  FIG. 1 ; 
         FIG. 4  is a schematic structural diagram of an optical composite film of the display panel shown in  FIG. 3 ; 
         FIG. 5  is a schematic structural diagram of an optical composite film of another implementation of the display panel shown in  FIG. 3 ; 
         FIG. 6  is a schematic structural diagram of a first optically-uniaxial optical film layer in the optical composite film shown in  FIG. 4 ; 
         FIG. 7  is a schematic structural diagram of a first optically-uniaxial optical film layer in the optical composite film shown in  FIG. 5 ; 
         FIG. 8  is a schematic structural diagram of a first optically-uniaxial optical film layer of another implementation of the optical composite film shown in  FIG. 5 ; 
         FIG. 9  is a schematic structural diagram of the first optically-uniaxial optical film layer, at another angle, shown in  FIG. 8 ; 
         FIG. 10  is a schematic structural diagram of the first optically-uniaxial optical film layer, at another angle, shown in  FIG. 8 ; 
         FIG. 11  is a schematic structural diagram of an optical composite film of another implementation of the display panel shown in  FIG. 3 ; 
         FIG. 12  is a schematic structural diagram of an optical composite film of another implementation of the display panel shown in  FIG. 3 ; 
         FIG. 13  is a schematic structural diagram of a reflection grating film layer in an optical composite film shown in  FIG. 4 ; 
         FIG. 14  is a schematic structural diagram of a display panel of another implementation of the display device shown in  FIG. 1 ; 
         FIG. 15  is a schematic structural diagram of a display panel of another implementation of the display device shown in  FIG. 1 ; 
         FIG. 16  is a schematic structural diagram of a display panel of another implementation of the display device shown in  FIG. 1 ; 
         FIG. 17  is a schematic structural diagram of a display panel of another implementation of the display device shown in  FIG. 1 ; 
         FIG. 18  is a schematic structural diagram of a display panel of another implementation of the display device shown in  FIG. 1 ; 
         FIG. 19  is a schematic structural diagram of a display panel of another implementation of the display device shown in  FIG. 1 ; and 
         FIG. 20  is a schematic structural diagram of a display panel of another implementation of the display device shown in  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     This application provides an optical composite film, a display panel, and a display device. To make objectives, technical solutions, and effects of this application clearer and more definite, this application is further described in detail below. It should be understood that specific embodiments described herein are only used to explain this application and are not intended to limit this application. 
     Referring to  FIG. 1 , a display device  10  of an implementation includes a backlight source  100  and a display panel  200 . 
     The backlight source  100  is a collimated light emitting backlight (BL) source, so that energy of light is centrally output at a front viewing angle. 
     Referring to  FIG. 2 , specifically, the backlight source  100  includes a reflector plate  110 , a light guide plate  120 , a prism film  130 , and a light-emitting diode (LED) light source  140 . The reflector plate  110 , the light guide plate  120 , and the prism film  130  are sequentially stacked, the light guide plate  120  has a light incident surface  121 , and the LED light source  140  and the light incident surface  121  are disposed opposite to each other. A side of the light guide plate  120  close to the reflector plate  110  is provided with a strip-shaped first groove  122 , the first groove  122  has a V-shaped cross section, and an extension direction of the first groove  122  is perpendicular to a light emergent direction of the LED light source  140 . A side of the light guide plate  120  close to the prism film  130  is provided with a strip-shaped second groove  123 , the second groove  123  has a V-shaped cross section, and an extension direction of the second groove  123  is parallel to a light emergent direction of the LED light source  140 . Optionally, a side of a prism of the prism film  130  is stacked on the light guide plate  120 . 
     Referring to  FIG. 3 , the display panel  200  includes an optical composite film  210 , a first glass film layer  220 , a first indium tin oxide (ITO) film layer  230 , a liquid crystal layer  240 , a second indium tin oxide film layer  250 , a metal grating film layer  260 , a second glass film layer  270 , and a photoresist layer  280 . 
     Referring to  FIG. 4 , the optical composite film  210  includes a first optically-uniaxial optical film layer  211 , a second optically-uniaxial optical film layer  212 , and a reflection grating film layer  213 . 
     The first optically-uniaxial optical film layer  211  has optical anisotropy, and when light passes through the first optically-uniaxial optical film layer  210 , a double-refraction phenomenon is generated. Light entering the first optically-uniaxial optical film layer  211  may be equivalent to two beams of light whose polarization directions are perpendicular to each other, and light perpendicular to a liquid crystal optical axis of the first optically-uniaxial optical film layer  211  is referred to as ordinary light, and is briefly referred to as O light; and light parallel to the liquid crystal optical axis of the first optically-uniaxial optical film layer  211  is referred to as extraordinary light, and is briefly referred to as E light. Optionally, the extraordinary light refractive index (ne 1 ) is an equivalent refractive index when an optical axis of the first optically-uniaxial optical film layer  211  is parallel to the light polarization direction; and the ordinary light refractive index (no 1 ) is an equivalent refractive index when the optical axis of the first optically-uniaxial optical film layer  211  is perpendicular to the light polarization direction, where ne 1 &gt;no 1 . 
     In an embodiment, an XYZ three-dimensional coordinate system is constructed, nx 1  is a refractive index of the first optically-uniaxial optical film layer  211  in a direction X, ny 1  is a refractive index of the first optically-uniaxial optical film layer  211  in a direction Y, nz 1  is a refractive index of the first optically-uniaxial optical film layer  211  in a direction Z, the direction Z is an extension direction of the film thickness of the first optically-uniaxial optical film layer  211 , and the extension direction of the film thickness is perpendicular a light emergent surface of the first optically-uniaxial optical film layer  211 . In this case, ne 1 =nx 1 &gt;no 1 =ny 1  or ne 1 =ny 1 &gt;no 1 =nx 1 , and no 1 =nz 1 . Specifically, a material of the first optically-uniaxial optical film layer  211  is a nematic-phase liquid crystal molecule material. 
     Optionally, the extraordinary light refractive index (ne 1 ) of the first optically-uniaxial optical film layer  211  is 1.0 to 2.5. 
     Specifically, the first optically-uniaxial optical film layer  211  includes a plate-shaped portion  211   a  and refraction portions  211   b.    
     The plate-shaped portion  211   a  is of a transparent flat-plate structure. 
     A plurality of refraction portions  211   b  exists, and the plurality of refraction portions  211   b  is disposed on a side of the plate-shaped portion  211   a . Referring to  FIG. 5 , specifically, the plurality of refraction portions  211   b  is camber columns or quadrangular prisms. 
     When the plurality of refraction portions  211   b  is the camber columns, the refraction portion  211   b  has a plurality of side surfaces, one of the plurality of side surfaces is an arc-shaped convex surface, and a side surface of the refraction portion  211   b  away from the arc-shaped convex surface is laminated to the plate-shaped portion  211   a . Specifically, the arc-shaped convex surface is a curved surface formed when an arc line is moved along an extension direction of the refraction portion  211   b . More specifically, the arc line is a circular arc line. 
     Optionally, the plurality of refraction portions  211   b  is arranged along a straight line, extension directions of the plurality of refraction portions  211   b  are parallel, and two neighboring refraction portions  211   b  are laminated or disposed at an interval. 
     Specifically, referring to  FIG. 6 , the refraction portion  211   b  has four side surfaces, and two side surfaces connected to the arc-shaped convex surface are parallel, an arc line of the refraction portion  211   b  is a circular arc line, and a chord corresponding to the arc line of the refraction portion  211   b  is parallel to a bottom surface close to the plate-shaped portion  211   a . A distance between a midpoint of the arc line of the refraction portion  211   b  and one of two side surfaces is r 1 , and a distance between midpoints of arc lines of two neighboring refraction portions  211   b  is P 1 , where P 1 ≥2r 1 . When P 1 &gt;2r 1 , the two neighboring refraction portions  211   b  are disposed at an interval; and when P 1 =2r 1 , the two neighboring refraction portions  211   b  are laminated. More specifically, P 1 ≤10 μm, to ensure that at least one arc-shaped convex surface in a sub-pixel enables light to be incident from an optically denser medium to an optically thinner medium and a refraction phenomenon occurs, thereby allocating light energy at a front viewing angle to a large viewing angle. 
     R is the radius of a circle on which the arc line is located, and D 1  is a maximum thickness of the first optically-uniaxial optical film layer  211 , where R≤D 1 . A larger curvature of the arc line indicates a larger range of the energy that can be allocated from the front viewing angle to the large viewing angle. 
     It should be noted that when the plurality of refraction portions  211   b  is camber columns, the plurality of refraction portions  211   b  is not limited to being arranged along a straight line, the plurality of refraction portions  211   b  may alternatively be arranged in a two-dimensional matrix, and two neighboring refraction portions  211   b  are disposed at an interval, so as to more effectively allocate light energy from the front viewing angle to two-dimensional directions, so that watching at a full viewing angle is more even. 
     When the plurality of refraction portions  211   b  is the quadrangular prisms, a side surface of the refraction portion  211   b  is laminated to the plate-shaped portion  211   a.    
     Optionally, the plurality of refraction portions  211   b  is arranged along a straight line, extension directions of the plurality of refraction portions  211   b  are parallel, and two neighboring refraction portions  211   b  are disposed at an interval. 
     R Specifically, referring to  FIG. 7 , the plurality of refraction portions  211   b  is square prisms, a half of the width of a side surface of the refraction portion  211   b  close to the plate-shaped portion  211   a  is r 2 , and a distance between centers of side surfaces of two neighboring prism portions close to the plate-shaped portion  211   a  is P 2 , where P 2 &gt;2r. Optionally, P 1 ≤10 μm, to ensure that at least one arc-shaped convex surface in a sub-pixel enables light to be incident from an optically denser medium to an optically thinner medium and a refraction phenomenon occurs, thereby allocating light energy at a front viewing angle to a large viewing angle. The thickness of the refraction portion  211   b  is d 2 , the thickness of the first optically-uniaxial optical film layer  211  is D 2 , and d 2  is not equal to 0, where d 2 ≤D 2 . 
     It should be noted that referring to  FIG. 8 , when the plurality of refraction portions  211   b  is square prisms, the plurality of refraction portions  211   b  is not limited to being arranged along a straight line, the plurality of refraction portions  211   b  may alternatively be arranged in a two-dimensional matrix, and two neighboring refraction portions  211   b  are disposed at an interval. 
     Referring to  FIG. 9  and  FIG. 10 , specifically, the plurality of refraction portions  211   b  is square prisms, a half of the width of a side surface of the refraction portion  211   b  close to the plate-shaped portion  211   a  in a direction X is rx, a half of the width of the side surface of the refraction portion  211   b  close to the plate-shaped portion  211   a  in a direction Y is ry, a distance between centers of side surfaces of two neighboring prism portions close to the plate-shaped portion  211   a  in the direction X is Px, and a distance between the centers of the side surfaces of the two neighboring prism portions close to the plate-shaped portion  211   a  in the direction Y is Py, where Px=Py, Px&gt;2rx, and Py&gt;2ry. Optionally, Px≤10 μm, and Py≤10 μm, to ensure that at least one arc-shaped convex surface in a sub-pixel enables light to be incident from an optically denser medium to an optically thinner medium and a refraction phenomenon occurs, thereby allocating light energy at a front viewing angle to a large viewing angle. The thickness of the refraction portion  211   b  is d 3 , the thickness of the first optically-uniaxial optical film layer  211  is D 3 , and d 3  is not equal to 0, where d 3 ≤D 3 . It should be noted that Px is not limited to being equal to Py, and Px may alternatively be greater than or less than Py. 
     The second optically-uniaxial optical film layer  212  is stacked on a side of the plate-shaped portion  211   a  close to the refraction portion  211   b , and the plurality of refraction portions  211   b  is accommodated in the second optically-uniaxial optical film layer  212 . The second optically-uniaxial optical film layer  212  has anisotropy. Specifically, a material of the second optically-uniaxial optical film layer  212  is a nematic-phase liquid crystal molecule material. 
     Optionally, the extraordinary light refractive index (ne 2 ) is an equivalent refractive index when an optical axis of the second optically-uniaxial optical film layer  212  is parallel to the light polarization direction; and the ordinary light refractive index (no 2 ) is an equivalent refractive index when the optical axis of the second optically-uniaxial optical film layer  211  is perpendicular to the light polarization direction, where ne 1 &gt;no 1 . 
     In an embodiment, an XYZ three-dimensional coordinate system is constructed, nx 2  is a refractive index of the second optically-uniaxial optical film layer  212  in a direction X, ny 2  is a refractive index of the second optically-uniaxial optical film layer  212  in a direction Y, nz 2  is a refractive index of the second optically-uniaxial optical film layer  212  in a direction Z, the direction Z is an extension direction of the film thickness of the second optically-uniaxial optical film layer  212 , and the extension direction of the film thickness is perpendicular a light emergent surface of the second optically-uniaxial optical film layer  212 . In this case, ne 2 =nx 2 &gt;no 2 =ny 2  or ne 2 =ny 2 &gt;no 2 =nx 2 , and no 1 =nz 1 . 
     Optionally, the ordinary light refractive index (no 2 ) of the second optically-uniaxial optical film layer  212  is 1.0 to 2.5. 
     In an embodiment, the extraordinary light refractive index (ne 1 ) of the first optically-uniaxial optical film layer  211  is greater than the ordinary light refractive index (no 2 ) of the second optically-uniaxial optical film layer  212 . Specifically, a difference between the extraordinary light refractive index (ne 1 ) of the first optically-uniaxial optical film layer  211  and the ordinary light refractive index (no 2 ) of the second optically-uniaxial optical film layer  212  is 0.01 to 2. A larger difference between the extraordinary light refractive index (ne 1 ) of the first optically-uniaxial optical film layer  211  and the ordinary light refractive index (no 2 ) of the second optically-uniaxial optical film layer  212  indicates easier allocation of light energy from the front viewing angle to the large viewing angle. More specifically, a direction of liquid crystal arrangement in the first optically-uniaxial optical film layer  211  is perpendicular to a direction of liquid crystal arrangement in the second optically-uniaxial optical film layer  212 . 
     The reflection grating film layer  213  is disposed on a side of the second optically-uniaxial optical film layer  212  away from the first optically-uniaxial optical film layer  211 . The reflection grating film layer  213  can turn natural light into polarized light, and is in place of a polarizing plate, to reduce the thickness of the display panel  200 . Optionally, the reflection grating film layer  213  is stacked on a side surface of the second optically-uniaxial optical film layer  212  away from the first optically-uniaxial optical film layer  211 . The thickness of the reflection grating film layer  213  is usually less than 20 μm. It can be learned that, the thickness of the reflection grating film layer  213  is far less than the thickness of the polarizing plate. 
     It should be noted that referring to  FIG. 11  and  FIG. 12 , the reflection grating film layer  213  is not limited to being stacked on a side surface of the second optically-uniaxial optical film layer  212  away from the first optically-uniaxial optical film layer  211 , and a part of the reflection grating film layer  213  may alternatively be inserted into a side of the second optically-uniaxial optical film layer  212  away from the optically-uniaxial optical film layer  211 . Optionally, the part of the reflection grating film layer  213  inserted into the second optically-uniaxial optical film layer  212  is disposed corresponding to a location of the refraction portion  211   b.    
     Referring to  FIG. 13 , specifically, the reflection grating film layer  213  includes a transparent substrate  213   a  and a metal layer  213   b.    
     The transparent substrate  213   a  is selected from one of a glass substrate, a silica gel substrate, a silicon dioxide substrate, a silicon nitride substrate, a polymethylmethacrylate substrate, and a polyethylene terephthalate substrate. 
     A plurality of metal layers  213   b  exists and is strip-shaped, and the plurality of metal layers  213   b  is disposed on the transparent substrate  213   a , where the plurality of metal layers  213   b  is disposed at intervals and in parallel, to dispose gratings. Optionally, the plurality of metal layers  213   b  is disposed on a side of the transparent substrate  213   a . Specifically, a material of the metal layer  213   b  is selected from one of gold, aluminum, and copper. 
     Optionally, the metal layer  213   b  has a width of 50 nm to 150 nm; the metal layer  213   b  has a thickness of 100 nm to 200 nm; and a spacing between two neighboring metal layers  213   b  is 100 nm to 200 nm. Specifically, the plurality of metal layers  213   b  is rectangular. 
     Light passes through the reflection grating film layer  213  and may be divided into an electromagnetic wave whose vibration direction is perpendicular to the metal layer  213   b  and an electromagnetic wave whose vibration direction is parallel to the metal layer  213   b . The reflection grating film layer  213  absorbs or reflects an electromagnetic wave component whose electromagnetic wave vibration component is parallel to the extension direction of the metal layer  213   b , only an electromagnetic wave component whose electromagnetic wave vibration component is perpendicular to the extension direction of the metal layer  213   b  penetrates, to obtain a function the same as that of the polarizing plate, and only polarized light perpendicular to a stretching direction of the polarizing plate passes through. 
     An operating principle of the optical composite film  210  is as follows: 
     Light is formed by horizontally polarized (a vibration direction of an electric field is a direction of 0° or 180°) light and vertically polarized (a vibration direction of the electric field is a direction of 90° or 270°) light, the reflection grating film layer  213  plays a role of absorbing polarized light and allowing polarized light to penetrate, and when an arrangement direction of the metal layer of the reflection grating film layer  213  is parallel to the direction of 90° or 270°, an extension direction of the metal layer of the reflection grating film layer  213  is parallel to the direction of 0° or 180°. It is predicted that vertically polarized light can pass through the reflection grating film layer  213 , an equivalent refractive index when the vertically polarized light passes through the first optically-uniaxial optical film layer  211  is ne 1 , and an equivalent refractive index when the vertically polarized light passes through the second optically-uniaxial optical film layer  212  is no 2 . Due to a difference between the refractive index of the first optically-uniaxial optical film layer  211  and the refractive index of the second optically-uniaxial optical film layer  212  (ne 1  is greater than no 2 ), when the vertically polarized light is incident from the first optically-uniaxial optical film layer  211  (optically denser medium) to the second optically-uniaxial optical film layer  212  (optically thinner medium), refraction is generated, and an optical phenomenon in which light energy is allocated from the front viewing angle to the large viewing angle occurs. 
     When the arrangement direction of the metal layer of the reflection grating film layer  213  is parallel to the direction of 0° or 180°, the extension direction of the metal layer of the reflection grating film layer  213  is parallel to the direction of 90° or 270°. It is predicted that horizontally polarized light can pass through the reflection grating film layer  213 , an equivalent refractive index when the horizontally polarized light passes through the first optically-uniaxial optical film layer  211  is ne 1 , and an equivalent refractive index when the horizontally polarized light passes through the second optically-uniaxial optical film layer  212  is no 2 . Due to a difference between the refractive index of the first optically-uniaxial optical film layer  211  and the refractive index of the second optically-uniaxial optical film layer  212  (ne 1  is greater than no 2 ), when the horizontally polarized light is incident from the first optically-uniaxial optical film layer  211  (optically denser medium) to the second optically-uniaxial optical film layer  212  (optically thinner medium), refraction is generated, and an optical phenomenon in which light energy is allocated from the front viewing angle to the large viewing angle occurs. Therefore, the optical composite film  210  not only can allocate light energy from the front viewing angle to the large viewing angle and improve the viewing angle color shift, but also can turn natural light into polarized light, so as to be in place of the polarizing plate. 
     The first glass film layer  220  is stacked on the optical composite film  210 . Optionally, the first glass film layer  220  is stacked on the reflection grating film layer  213 . 
     The first indium tin oxide film layer  230  is stacked on a side of the first glass film layer  220  away from the optical composite film  210 . 
     The liquid crystal layer  240  is stacked on a side of the first indium tin oxide film layer  230  away from the first glass film layer  220 . 
     The second indium tin oxide film layer  250  is stacked on a side of the liquid crystal layer  240  away from the first indium tin oxide film layer  230 . 
     The metal grating film layer  260  is stacked on a side of the second indium tin oxide film layer  250  away from the liquid crystal layer  240 . The metal grating film layer  260  has a function and a material roughly the same as those of the reflection grating film layer  213 , to be in place of an upper polarizing plate, and further reduce the thickness of the display panel  200 . 
     The second glass film layer  270  is stacked on a side of the metal grating film layer  260  away from the second indium tin oxide film layer  250 . 
     The photoresist layer  280  is stacked between the metal grating film layer  260  and the second glass film layer  270 . 
       FIG. 14  and  FIG. 15 , optionally, the display panel  200  further includes a compensation film layer  290 , and the compensation film layer  290  is stacked between the second indium tin oxide film layer  250  and the metal grating film layer  260 ; or the compensation film layer  290  is stacked between the first glass film layer  220  and the first indium tin oxide film layer  230 . The compensation film layer  290  can be in place of an optical function of a compensation film in the polarizing plate. Optionally, the compensation film layer  290  has optical anisotropy. Specifically, a material of the compensation film layer  290  is a nematic-phase liquid crystal molecule material. More specifically, the compensation film layer  290  is prepared by using a process of liquid crystal molecule coating or ultraviolet (UV) light curing. 
     Referring to  FIG. 16 , in an embodiment, a quantity of compensation film layers  290  is two, one of the two compensation film layers  290  is stacked between the second indium tin oxide film layer  250  and the metal grating film layer  260 , and the other of the two compensation film layers  290  is stacked between the first glass film layer  220  and the first indium tin oxide film layer  230 . 
     It should be noted that referring to  FIG. 17 , the display panel  200  is not limited to the foregoing structure, and the photoresist layer  280  of the display panel may alternatively be stacked between the first glass film layer  220  and the first indium tin oxide film layer  230 . 
     Referring to  FIG. 18  and  FIG. 19 , optionally, the compensation film layer  290  is stacked between the second indium tin oxide film layer  250  and the metal grating film layer  260 ; or the compensation film layer  290  is stacked between the photoresist layer  280  and the first glass film layer  220 . 
     Referring to  FIG. 20 , in an embodiment, a quantity of compensation film layers  290  is two, one of the two compensation film layers  290  is stacked between the second indium tin oxide film layer  250  and the metal grating film layer  260 , and the other of the two compensation film layers  290  is stacked between the photoresist layer  280  and the first glass film layer  220 . 
     It should be noted that the display panel  200  is not limited to the foregoing stacking structure, and materials having special functions may be added to different film layers according to different requirements. For example, another function material is added to a single-function film layer, to obtain a multifunction film layer. In addition, an order of stacking film layers in the display panel  200  may be changed according to a required function, and another function film layer and the like may be further added according to a requirement. 
     The foregoing display device  10  has at least the following advantages: 
     1. The foregoing first optically-uniaxial optical film layer  211  includes a plate-shaped portion  211   a  and a plurality of refraction portions  211   b  disposed on a side of the plate-shaped portion  211   a , the plurality of refraction portions  211   b  is camber columns or quadrangular prisms, the second optically-uniaxial optical film layer  212  is stacked on a side of the plate-shaped portion  211   a  close to the refraction portion  211   b , and the extraordinary light refractive index of the first optically-uniaxial optical film layer  211  is greater than the ordinary light refractive index of the second optically-uniaxial optical film layer  212 . When light is incident from the first optically-uniaxial optical film layer  211  to the second optically-uniaxial optical film layer  212 , due to a difference between refractive indexes, the light is incident from an optically denser medium to an optically thinner medium and a refraction phenomenon occurs, to allocate light energy from the front viewing angle to the large viewing angle, and resolve a problem of color shift of the display panel  200  at the large viewing angle. Moreover, the reflection grating film layer  213  is disposed on a side of the second optically-uniaxial optical film layer  212  away from the first optically-uniaxial optical film layer  211 . The reflection grating film layer  213  can turn natural light into polarized light, and is in place of a relatively thick polarizing plate, to make the display panel  200  relatively thin. Therefore, the foregoing optical composite film  210  not only can alleviate the color shift of the display panel  200  at the large viewing angle, but also can make the display panel  200  relatively thin. 
     2. In the display panel  200 , RGB sub-pixels do not need to be divided into a main pixel structure and a sub-pixel structure, to avoid design of a metal wire or a TFT element to drive a sub-pixel, which would cause a sacrifice in an opening region of transmissible light and affect a transmission rate of the panel. Moreover, display resolution and driving frequency of the display panel  200  are maintained. Therefore, the foregoing optical composite film  210  can improve the viewing angle color shift, and the panel has a relatively good transmission rate. 
     3. The reflection grating film layer  213  of the foregoing display panel  200  is in place of a lower polarizing plate, and the metal grating film layer  260  is in place of an upper polarizing plate, to make the display panel  200  relatively thin. 
     It should be understood that the application of this application is not limited to the above examples, and persons of ordinary skill in the art can make improvements and modifications accordance to the above descriptions, and all such improvements and modifications shall fall within the protection scope of the appended claims.