Viewing angle expanding film, polaroid and display device

Abstract

The invention relates to a visual angle expanding film, a polaroid and a display device, the visual angle expanding film comprises a first refractive index layer and a second refractive index layer, and the first refractive index layer comprises at least one patterned refractive unit; the second refractive index layer covers the refraction unit, and the refractive index of the second refractive index layer is greater than that of the first refractive index layer; wherein the refraction unit comprises a first refraction structure and a second refraction structure, the first refraction structure extends in the first direction, the second refraction structure extends in the second direction, and the first direction intersects with the second direction. The patterned refraction unit of the visual angle expanding film is composed of the first refraction structure and the second refraction structure in different directions, diffusion of polarized light in different directions can be achieved, and the risk that moire patterns are poor due to mutual interference between the polarized light and periodic structures of pixels and a backlight diaphragm can be reduced; and the matching angle of the absorption axis of the polaroid is not limited by the visual angle expanding film.

Description

Technical Field

[0001] The present application relates to the field of display technology, and in particular to a viewing angle expansion film, a polarizing film and a display device. Background Art

[0002] Liquid Crystal Display (LCD) is generally composed of a liquid crystal box and polarizers located on both sides of the liquid crystal box. Polarizers are indispensable materials for liquid crystal displays. For displays with vertical alignment liquid crystal (VA) display mode, the larger the viewing angle, the more light leakage there is. In order to improve the display effect under a wide viewing angle, the industry usually attaches a viewing angle expansion functional film layer to the polarizer. On the one hand, it refracts the light emitted from the front to the wide viewing angle, and on the other hand, it refracts the light emitted from the wide viewing angle to the front. Through the simultaneous action of these two aspects, the light emitted from the front and the light emitted from the wide viewing angle are mixed, so as to achieve consistent display effects under normal viewing and wide viewing angles.

[0003] Among the existing viewing angle expansion film products, some viewing angle expansion films use a patterned linear arrangement of periodic structures. These periodic structures are prone to interfere with the periodic structures of pixels and backlight films at certain angles, resulting in moire defects. Some viewing angle expansion films use a rod-shaped particle coating design. This particle structure can only achieve horizontal viewing angle expansion. Since the particles can only be produced by horizontal coating, the POL absorption axis angle is limited to only support a combination of 90° up and 0° down, and the backlight prism structure design will also be limited by this angle. Summary of the invention

[0004] The embodiments of the present application provide a viewing angle expansion film, a polarizer, and a display device to solve the above problems.

[0005] In order to achieve the above object, according to a first aspect of the present application, a viewing angle expansion film is provided, comprising:

[0006] A first refractive index layer including at least one patterned refractive unit; and

[0007] A second refractive index layer, covering the refractive unit, wherein the refractive index of the second refractive index layer is greater than the refractive index of the first refractive index layer;

[0008] The refraction unit includes a first refraction structure and a second refraction structure, the first refraction structure extends along a first direction, the second refraction structure extends along a second direction, and the first direction intersects with the second direction.

[0009] In some embodiments, the first refractive structure is connected to the second refractive structure at one end, and the other end is open.

[0010] In some embodiments, the first refractive structure and the second refractive structure cross each other in an X shape.

[0011] In some embodiments, the refractive index of the first refractive index layer ranges from 1.1 to 1.4, the refractive index of the second refractive index layer ranges from 1.3 to 1.7, and the difference between the refractive index of the second refractive index layer and the refractive index of the first refractive index layer ranges from 0.1 to 0.3.

[0012] In some embodiments, a cross-sectional shape of the first refractive structure or the second refractive structure is a polygon or a semicircle.

[0013] In some embodiments, the cross-sectional shape of the first refractive structure and the second refractive structure is a trapezoid, the angle range of the base angle α of the trapezoid is 45°≤α<90°, the range of the height H1 of the trapezoid is 10μm≤H1≤100μm, and the length range of the upper base D1 of the trapezoid is 5μm≤D1≤100μm, wherein the upper base is the side in contact with the second refractive index layer.

[0014] In some embodiments, the first refractive index layer includes a plurality of the refractive units, the plurality of the refractive units are arranged at intervals, and a distance between two adjacent refractive units ranges from 0 μm to 50 μm.

[0015] According to a second aspect of the present application, a polarizer is provided, comprising:

[0016] a polarizing layer; and

[0017] The viewing angle widening film as described above is disposed on one side of the polarizing layer.

[0018] According to a third aspect of the present application, a display device is provided, including:

[0019] Display panel;

[0020] A first polarizer, disposed on the light-emitting side of the display panel, the first polarizer comprising a polarizing layer and the viewing angle expansion film as described above, the viewing angle expansion film being located on a side of the polarizing layer away from the display panel; and

[0021] The second polarizer is arranged on a side of the display panel away from the first polarizer.

[0022] In some embodiments, the display panel includes a plurality of pixel units arranged in an array, the pixel unit includes a plurality of sub-pixels arranged along a third direction, the sub-pixels extend along a fourth direction, and the third direction is perpendicular to the fourth direction;

[0023] The length of the pixel unit in the third direction is a, and the length of the pixel unit in the fourth direction is b;

[0024] The plurality of refractive units are arranged in an array along the third direction and the fourth direction, the width of the refractive unit in the third direction is L1, the distance between two adjacent refractive units in the third direction is L2, L1+L2=na, the width of the refractive unit in the fourth direction is L3, the distance between two adjacent refractive units in the fourth direction is L4, L3+L4=mb;

[0025] Wherein, n and m are selected from integers of 1 to 10.

[0026] The present application provides a viewing angle expansion film, a polarizer and a display device. The viewing angle expansion film of the present application includes a first refractive index layer and a second refractive index layer, the refractive index of the second refractive index layer is greater than the refractive index of the first refractive index layer, wherein the first refractive index layer includes a patterned refractive unit, the refractive unit includes a first refractive structure and a second refractive structure, the first refractive structure and the second refractive structure intersect, that is, the refractive unit is composed of refractive structures in different directions, the irregular shape of the refractive unit can effectively avoid the risk of moiré defects caused by mutual interference between the refractive unit and the periodic structures in the pixel and the backlight film, and because the refractive unit includes refractive structures in different directions, the diffusion of polarized light in different directions can be achieved, so the absorption axis matching angle of the first polarizer and the second polarizer of the display device of the present application is not limited by the viewing angle expansion film. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application, and those skilled in the art can obtain other drawings based on these drawings without creative work.

[0028] In order to more completely understand the present application and its beneficial effects, the following description will be given in conjunction with the accompanying drawings, wherein the same figure numbers represent the same parts in the following description.

[0029] Figure 1 It is a structural schematic diagram of a viewing angle expansion film provided by the prior art;

[0030] Figure 2 It is a top view of a viewing angle expansion film provided by the prior art;

[0031] Figure 3 is a schematic structural diagram of a viewing angle expansion film provided in an embodiment of the present application;

[0032] Figure 4 is a top view of a viewing angle expansion film provided in an embodiment of the present application;

[0033] Figure 5 is a cross-sectional view of a first refractive structure or a second refractive structure of a viewing angle expansion film provided in an embodiment of the present application;

[0034] Figure 6 This is a schematic diagram of the diffusion direction of the outgoing light of a viewing angle expansion film provided in an embodiment of the present application;

[0035] Figure 7 is a top view of a refraction unit of a viewing angle expansion film provided in an embodiment of the present application;

[0036] Figure 8 is a cross-sectional view of a refraction unit of a viewing angle expansion film provided in an embodiment of the present application;

[0037] Fig. 9 is a schematic structural diagram of a polarizer provided in an embodiment of the present application;

[0038] Fig.10 is a structural schematic diagram of a display device provided in an embodiment of the present application;

[0039] Fig.11 is a schematic diagram of a pixel unit of a display device provided in an embodiment of the present application;

[0040] Fig.12 This is a schematic diagram of the alignment of a pixel and a refraction unit of a display device provided in an embodiment of the present application.

[0041] Description of reference numerals:

[0042] 10. Display device; 100. Viewing angle expansion film; 101. First refractive index layer; 102. Second refractive index layer; 110. Refraction unit; 111. First refractive structure; 112. Second refractive structure; 200. Polarizer; 201. First polarizer; 210. Polarizing layer; 220. First optical protective film; 230. Second optical protective film; 240. Substrate; 300. Second polarizer; 400. Display panel; 401. Red sub-pixel; 402. Green sub-pixel; 403. Blue sub-pixel; 410. Pixel unit; 101'. High refractive index layer; 102'. Low refractive index layer; 102'. Refraction structure. DETAILED DESCRIPTION

[0043] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present application.

[0044] See also Figure 1 , which is a viewing angle expansion film in the prior art, and includes a high refractive index layer 101' and a low refractive index layer 102', wherein the refractive index of the high refractive index layer 101' is greater than the refractive index of the low refractive index layer 102', wherein the high refractive index layer 101' includes a refractive structure 110'.

[0045] In some prior art, the refractive structure 110' is a patterned structure. These refractive structures 110' are usually straight and extend in the same direction. Such a periodic structure is easy to interfere with the periodic structure of the pixel and the backlight film at a certain angle, resulting in Moire defects. Figure 2 As shown, in order to overcome the moiré defect, the refractive structure 110' usually needs to be rotated by a certain angle, but this method will result in different products needing to individually confirm the angles that need to be rotated according to the design of each product to ensure that no moiré defect occurs, which will increase the time required for verification. In addition, in order to achieve different graphic angles of the refractive structure 110', different jigs need to be made, which will also increase the material production cycle and increase costs.

[0046] In other prior arts, the refractive structure 110' is a rod-shaped particle formed by a coating process, but the particle can only be made by a coating method in a horizontal direction. Figure 1 As shown in the light emitting direction, the viewing angle can only be expanded horizontally, that is, the viewing angle can be expanded in a single direction. Therefore, the viewing angle expansion film only supports the combination of polarizers with an absorption axis of 90° for the upper polarizer and 0° for the lower polarizer, which limits the absorption axis angle matching of the polarizers.

[0047] See also Figure 3-Figure 5The present application provides a viewing angle expansion film 100, which includes a first refractive index layer 101 and a second refractive index layer 102. The first refractive index layer 101 includes at least one patterned refractive unit 110, and the refractive unit 110 includes a first refractive structure 111 and a second refractive structure 112. The first refractive structure 111 extends along a first direction A, and the second refractive structure 112 extends along a second direction B. The first direction A intersects with the second direction B, that is, at least one angle between the first direction A and the second direction B is greater than 0° and less than or equal to 90°. The second refractive index layer 102 covers the refractive unit 110, and the refractive index of the second refractive index layer 102 is greater than the refractive index of the first refractive index layer 101.

[0048] In the present application, the light incident on the viewing angle expansion film 100 first enters the refraction unit 110, then enters the second refractive index layer 102 by the refraction unit 110, and then exits after passing through the second refractive index layer 102. Since the refractive index of the second refractive index layer 102 is greater than the refractive index of the first refractive index layer 101, the light passing through the viewing angle expansion film 100 can achieve the expansion of the viewing angle of the light. For details, please refer to Figure 5 , is a schematic diagram of the optical path of light passing through the viewing angle expansion film 100, Figure 5 The refractive index of the first refractive index layer 101 is n1, the refractive index of the second refractive index layer 102 is n2, the incident angle of the light is θ1, and the exit angle is θ2. According to the law of refraction, n1sinθ1=n2sinθ2, since n1<n2, θ1>θ2, therefore, the viewing angle of the light is expanded after passing through the viewing angle expansion film 100.

[0049] In some embodiments, the refractive index of the first refractive index layer 101 is in the range of 1.1 to 1.4, and the material of the first refractive index layer 101 includes but is not limited to at least one of polyethylene, polypropylene, polyvinyl alcohol, polycarbonate, polyacrylic acid, or polyethylene terephthalate. The refractive index of the second refractive index layer 102 is in the range of 1.3 to 1.7, and the material of the second refractive index layer 102 includes but is not limited to at least one of epoxy resin, acrylic resin, polyurethane resin, silicone resin, phenolic resin, or thermosetting resin.

[0050] In some embodiments, the difference between the refractive index of the second refractive index layer 102 and the refractive index of the first refractive index layer 101 ranges from 0.1 to 0.3, and further ranges from 0.1 to 0.2. When the difference between the refractive index of the second refractive index layer 102 and the refractive index of the first refractive index layer 101 is within the above range, the viewing angle expansion effect can be further enhanced.

[0051] In the present application, the refractive unit 110 of the viewing angle expansion film 100 includes a first refractive structure 111 extending along a first direction A and a second refractive structure 112 extending along a second direction B. The first direction A and the second direction B intersect, and the angle between the first direction A and the second direction B is θ, 0°<θ≤90°. The periodic structures in the pixels and backlight films of the existing display devices are generally regular structures arranged in arrays along the horizontal and vertical directions, which are easy to interfere with the regular linear arrangement refractive structures in the existing viewing angle expansion films. The refractive unit 110 of the present application is composed of a plurality of refractive structures in different directions. This irregular shape can effectively avoid the refractive unit 110 from interfering with the regular periodic structures in the pixels and backlight films to produce moiré defects.

[0052] Furthermore, since the first refractive structure 111 and the second refractive structure 112 of the refractive unit 110 of the present application extend in different directions, each refractive unit 110 can achieve light diffusion in multiple directions, and thus can achieve diffusion of polarized light in different directions. Therefore, the absorption axis angle combination of the upper polarizer and the lower polarizer of the display device using the viewing angle expansion film 100 of the present application is no longer restricted, and the application scope of the viewing angle expansion film 100 can be expanded.

[0053] In some embodiments, the angle θ between the first refractive structure 111 and the second refractive structure 112 is in the range of 30° to 60°, that is, the angle θ between the first direction A and the second direction B is in the range of 30° to 60°. When the angle between the first refractive structure 111 and the second refractive structure 112 is within this range, the viewing angle expansion effect of the viewing angle expansion film 100 is optimal, which better matches the user's viewing experience.

[0054] In the present application, a refraction unit 110 may include one or more first refraction structures 111 and one or more second refraction structures 112. In the refraction unit 110, the first refraction structure 111 and the second refraction structure 112 may be connected to each other, that is, connected at the intersection, for example, the first refraction structure 111 and the second refraction structure 112 may be combined in a V-shape, an X-shape, a cross-shape, etc., but is not limited thereto.

[0055] In some embodiments, in the refraction unit 110, one end of the first refraction structure 111 is connected to the second refraction structure 112, and the other end is open. For example, one end of the first refraction structure 111 is connected to one end of the second refraction structure 112 to form a V shape, or two ends of the first refraction structures 111 are connected to the ends of two second refraction structures 112 to form an X shape, but the present invention is not limited thereto.

[0056] In some other embodiments, in the refraction unit 110, the first refraction structure 111 and the second refraction structure 112 may not be connected. For example, the two structures may be combined to form a V-shaped, X-shaped, or cross-shaped arrangement, but are not connected at the intersection.

[0057] In some embodiments, the combined structure of the first refractive structure 111 and the second refractive structure 112 may be an axisymmetric pattern, so as to achieve a uniform viewing angle diffusion effect.

[0058] In some other embodiments, the combined structure of the first refractive structure 111 and the second refractive structure 112 may be an asymmetric pattern, which is not limited here.

[0059] In one embodiment, see Figure 4 and Figure 6 , the refraction unit 110 can be X-shaped, that is, the first refraction structure 111 and the second refraction structure 112 cross to form an X-shape. When the refraction unit 110 is X-shaped, with its intersection as the center, its refraction structure extends in four different directions, and the refraction unit 110 can achieve light diffusion in four different directions, which is more conducive to improving the wide viewing angle effect compared to the existing viewing angle expansion film that can only expand the viewing angle in a single direction. In addition, when the refraction unit 110 is X-shaped, since it can achieve light diffusion in multiple different directions, the absorption axis angle matching of the upper polarizer and the lower polarizer of the display device using the viewing angle expansion film 100 of the present application is no longer restricted.

[0060] In this embodiment, the refraction unit 110 is X-shaped, and may be formed by connecting the ends of two first refraction structures 111 and two second refraction structures 112, or may be formed by crossing a first refraction structure 111 and a second refraction structure 112. The shape of the refraction unit 110 may be formed by stamping a corresponding mold, or may be formed by other patterning methods, which is not limited here.

[0061] In some embodiments, see Figure 7 The first refractive structure 111 and the second refractive structure 112 may be a rod-shaped structure having a long axis and a short axis, wherein the long axis is perpendicular to the short axis and the length of the long axis is greater than the short axis. Specifically, the first refractive structure 111 has a long axis E1, and the extension direction of the long axis E1 is the first direction A. The second refractive structure 112 has a long axis E2, and the extension direction of the long axis E2 is the second direction B. The angle between E1 and E2 is θ. The use of a rod-shaped structure is conducive to the design and adjustment of the angles of the first refractive structure 111 and the second refractive structure 112, and is conducive to improving the light utilization rate along the long axis direction of the rod-shaped structure, and the rod-shaped structure is easy to manufacture.

[0062] In some embodiments, the refraction unit 110 may be an axisymmetric structure, the first refraction structure 111 and the second refraction structure 112 have the same structure, and the lengths of E1 and E2 are equal.

[0063] In the present application, the cross-sectional shape of the first refractive structure 111 and the second refractive structure 112 may be a polygon or a semicircle, but is not limited thereto.

[0064] In some embodiments, see Figure 8 The cross-sectional shape of the first refractive structure 111 and the second refractive structure 112 is a trapezoid, such as an isosceles trapezoid, the angle range of the base angle α of the trapezoid is 45°≤α<90°, the range of the height H1 of the trapezoid is 10μm≤H1≤100μm, and the length range of the upper base D1 of the trapezoid is 5μm≤D1≤100μm, wherein the upper base of the trapezoid is the side in contact with the second refractive index layer 102, the lower base of the trapezoid is opposite to the upper base, and the incident light is incident from the lower base side to the first refractive structure 111 or the second refractive structure 112.

[0065] In some other embodiments, the cross-sectional shapes of the first refractive structure 111 and the second refractive structure 112 may also be non-isosceles trapezoids, triangles, or semicircles, etc. The principles are similar and will not be described in detail herein.

[0066] See also Figure 8 In the structure of the viewing angle expansion film 100, the second refractive index layer 102 covers the refractive unit 110, and the thickness H2 of the second refractive index layer 102 is greater than the height H1 of the first refractive structure 111 and the second refractive structure 112. The thickness H2 of the second refractive index layer 102 ranges from 20 μm to 120 μm.

[0067] In some embodiments, see Figure 4 , the first refractive index layer 101 may include a plurality of refractive units 110, the plurality of refractive units 110 are arranged at intervals, and the distance between two adjacent refractive units 110 ranges from 0 μm to 50 μm. For example, the plurality of refractive units 110 may be arranged in an array along the third direction X and the fourth direction Y, the distance L2 between two adjacent refractive units 110 in the third direction X ranges from 0 μm to 50 μm, and the distance L4 between two adjacent refractive units 110 in the fourth direction Y ranges from 0 μm to 50 μm. When the distance between two adjacent refractive units 110 is within the above range, the light utilization rate is higher and the viewing angle expansion effect is better.

[0068] See also Fig. 9The present application also provides a polarizer 200, which includes a polarizing layer 210 and the viewing angle expansion film 100 as described above. The viewing angle expansion film 100 is arranged on one side of the polarizing layer 210. The viewing angle expansion film 100 has all the beneficial effects of the viewing angle expansion film 100 as described above, which will not be repeated here.

[0069] Specifically, when the polarizer 200 is used for display products, the viewing angle expansion film 100 is disposed on the light emitting side of the polarizing layer 210 , and the second refractive index layer 102 of the viewing angle expansion film 100 is located on the side of the first refractive index layer 101 away from the polarizing layer 210 .

[0070] In some embodiments, see Fig. 9 The polarizer 200 further includes a first optical protective film 220 located on a side of the polarizing layer 210 away from the viewing angle expanding film 100 , a second optical protective film 230 located between the polarizing layer 210 and the viewing angle expanding film 100 , and a substrate 240 located on a side of the viewing angle expanding film 100 away from the second optical protective film 230 .

[0071] The first optical protective film 220 has a compensatory effect in addition to a protective effect. The material of the first optical protective film 220 includes but is not limited to at least one of polycarbonate film (PC), cycloolefin polymer (COP), triacetyl cellulose film (TAC), etc. The second optical protective film 230 plays a role in protecting the polarizing layer 210. The material of the second optical protective film 230 includes but is not limited to at least one of triacetyl cellulose film (TAC), polyethylene terephthalate film (PET), acrylic film (PMMA), etc. The polarizing layer 210 plays a polarizing role. The material of the polarizing layer 210 includes but is not limited to polyvinyl alcohol (PVA), etc.

[0072] See also Fig.10 The present application also provides a display device 10 , including a first polarizer 201 and a second polarizer 300 , and a display panel 400 located between the first polarizer 201 and the second polarizer 300 .

[0073] The display panel 400 may be a liquid crystal display panel, but is not limited thereto.

[0074] The first polarizer 201 is disposed on the light-emitting side of the display panel 400. Fig. 9 The first polarizer 201 has the same structure as the polarizer 200 , including a polarizing layer 210 and the viewing angle expansion film 100 as described above, and the viewing angle expansion film 100 is located on a side of the polarizing layer 210 away from the display panel 400 .

[0075] Among them, the first polarizer 201 also includes a first optical protective film 220 located on the side of the polarizing layer 210 away from the viewing angle expansion film 100, a second optical protective film 230 located between the polarizing layer 210 and the viewing angle expansion film 100, and a substrate 240 located on the side of the viewing angle expansion film 100 away from the second optical protective film 230, wherein the first optical protective film 220 is close to the light emitting side of the display panel.

[0076] The second polarizer 300 is disposed on a side of the display panel 400 away from the first polarizer 201 . The second polarizer 300 is a conventional polarizer and does not have a viewing angle expansion film 100 .

[0077] In some embodiments, the display device 10 may further include a backlight module (not shown in the figure), which is disposed on a side of the second polarizer 300 away from the display panel 400 to provide a backlight source.

[0078] In some embodiments, see Figure 11-Figure 12 , the display panel 400 includes a plurality of pixel units 410 arrayed along a third direction X and a fourth direction Y, the pixel unit 410 includes a plurality of sub-pixels arranged along the third direction X, the sub-pixels extend along the fourth direction Y, and the third direction X is perpendicular to the fourth direction Y. For example, the pixel unit 410 may include a red sub-pixel 401, a green sub-pixel 402, and a blue sub-pixel 403, and the red sub-pixel 401, the green sub-pixel 402, and the blue sub-pixel 403 are arranged along the third direction X. The pixel size of the pixel unit 410 is defined as a*b, that is, the length of the pixel unit 410 in the third direction X is a, and the length in the fourth direction Y is b.

[0079] See also Figure 4 , the viewing angle expansion film 100 includes a plurality of refractive units 110, and the plurality of refractive units 110 are arranged in an array along the third direction X and the fourth direction Y. The width of the refractive unit 110 in the third direction X is L1, and the distance between two adjacent refractive units 110 in the third direction X is L2, and L1+L2 is an integer multiple of a, that is, L1+L2=na; the width of the refractive unit 110 in the fourth direction Y is L3, and the distance between two adjacent refractive units 110 in the fourth direction Y is L4, and L3+L4 is an integer multiple of b, that is, L3+L4=mb; wherein n and m are integers. That is to say, one refractive unit 110 may correspond to one or more pixel units 410. In the present application, the refractive unit 110 may be manufactured by an embossing process, but due to the limitation of the embossing process, n and m are selected from 1 to 10.

[0080] In some embodiments, see Fig.12, n=1, m=1, that is, one refraction unit 110 corresponds to one pixel unit 410, and the light emitted from each pixel unit 410 can be diffused by a corresponding refraction unit 110 of the viewing angle expansion film 100, which is beneficial to improve the light utilization rate, improve the viewing angle expansion effect, and thus improve the display quality.

[0081] The present application provides a viewing angle expansion film, a polarizer and a display device. The viewing angle expansion film of the present application includes a first refractive index layer and a second refractive index layer, the refractive index of the second refractive index layer is greater than the refractive index of the first refractive index layer, wherein the first refractive index layer includes a patterned refractive unit, the refractive unit includes a first refractive structure and a second refractive structure, the first refractive structure and the second refractive structure intersect, that is, the refractive unit is composed of refractive structures in different directions, the irregular shape of the refractive unit can effectively avoid the risk of moiré defects caused by mutual interference between the refractive unit and the periodic structures in the pixel and the backlight film, and because the refractive unit includes refractive structures in different directions, the diffusion of polarized light in different directions can be achieved, so the absorption axis matching angle of the first polarizer and the second polarizer of the display device of the present application is not limited by the viewing angle expansion film.

[0082] In the description of this application, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0083] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0084] The embodiments, implementation methods and related technical features of the present application can be combined and replaced with each other without conflict.

[0085] The above are only preferred embodiments of the present application and do not constitute any form of limitation to the present application. However, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present application without departing from the content of the technical solution of the present application are still within the scope of the technical solution of the present application.

Claims

1. A viewing angle expansion film, characterized in that: include: A first refractive index layer including at least one patterned refractive unit; as well as A second refractive index layer, covering the refractive unit, wherein the refractive index of the second refractive index layer is greater than the refractive index of the first refractive index layer; The refraction unit includes a first refraction structure and a second refraction structure, the first refraction structure extends along a first direction, the second refraction structure extends along a second direction, and the first direction intersects with the second direction.

2. The viewing angle expansion film according to claim 1, characterized in that: The first refractive structure is connected to the second refractive structure at one end, and the other end is open.

3. The viewing angle expansion film according to claim 1, characterized in that: The first refractive structure and the second refractive structure cross each other to form an X shape.

4. The viewing angle expansion film according to claim 1, characterized in that: The refractive index of the first refractive index layer ranges from 1.1 to 1.4, the refractive index of the second refractive index layer ranges from 1.3 to 1.7, and the difference between the refractive index of the second refractive index layer and the refractive index of the first refractive index layer ranges from 0.1 to 0.

3.

5. The viewing angle expansion film according to claim 1, characterized in that: The cross-sectional shape of the first refractive structure or the second refractive structure is polygonal or semicircular.

6. The viewing angle expansion film according to claim 5, characterized in that: The cross-sectional shape of the first refractive structure and the second refractive structure is a trapezoid, the angle range of the base angle α of the trapezoid is 45°≤α<90°, the range of the height H1 of the trapezoid is 10μm≤H1≤100μm, and the length range of the upper base D1 of the trapezoid is 5μm≤D1≤100μm, wherein the upper base is the side in contact with the second refractive index layer.

7. The viewing angle expansion film according to claim 1, characterized in that: The first refractive index layer includes a plurality of the refractive units, the plurality of the refractive units are arranged at intervals, and a distance between two adjacent refractive units ranges from 0 μm to 50 μm.

8. A polarizer, characterized in that: include: Polarizing layer; as well as The viewing angle-enhancing film according to any one of claims 1 to 7, arranged on one side of the polarizing layer.

9. A display device, characterized in that: include: Display panel; A first polarizer, arranged on the light-emitting side of the display panel, the first polarizer comprising a polarizing layer and the viewing angle expanding film according to any one of claims 1 to 7, the viewing angle expanding film being located on a side of the polarizing layer away from the display panel; as well as The second polarizer is arranged on a side of the display panel away from the first polarizer.

10. The display device according to claim 9, characterized in that: The display panel includes a plurality of pixel units arranged in an array, the pixel units include a plurality of sub-pixels arranged along a third direction, the sub-pixels extend along a fourth direction, and the third direction is perpendicular to the fourth direction; The length of the pixel unit in the third direction is a, and the length of the pixel unit in the fourth direction is b; The plurality of refractive units are arranged in an array along the third direction and the fourth direction, the width of the refractive unit in the third direction is L1, the distance between two adjacent refractive units in the third direction is L2, L1+L2=na, the width of the refractive unit in the fourth direction is L3, the distance between two adjacent refractive units in the fourth direction is L4, L3+L4=mb; Here, n and m are selected from integers of 1 to 10.

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