Backlight module and display device

Abstract

The utility model provides a backlight module and a display device, and the backlight module comprises a back plate which comprises a bottom plate and a side plate, and the bottom plate and the side plate define a containing cavity; the optical assembly is located in the containing cavity, the optical assembly comprises at least one first brightness enhancement film, a plurality of first prisms are arranged on the side, away from the bottom plate, of the first brightness enhancement film, and the vertex angle of each first prism is larger than 90 degrees and smaller than 105 degrees, or the vertex angle of each first prism is a round angle. According to the backlight module and the display device, the problem of large-viewing-angle light leakage caused by a bright enhancement film can be solved.

Description

Technical Field

[0001] The present application relates to the field of display technology, and in particular, to a backlight module and a display device. Background Art

[0002] When smart connected cars become the "third space" outside of offices and homes, in-vehicle displays become the "windows" for communication and interaction between people and cars. Today, intelligence has become a major trend in the development of automobiles. Smart cockpits have put forward new requirements for in-vehicle displays. Innovative applications of in-vehicle displays such as augmented reality head-up display (AR HUD), transparent window display, and large entertainment screens for co-pilot and rear seats are constantly iterating and innovating. At present, the mainstream in-vehicle display panels are still dominated by liquid crystal display panels (LCDs). Liquid crystal display panels must be used with backlight modules (BLUs). Whether it is a mini-LED BLU or a side-entry BLU, the backlight module architecture includes a bright enhancement film (BEF). The bright enhancement film is also called a prism film, which has a prism structure. The prism structure will deflect the incident light of 40°~51.5° / 114°~128.5° to a large angle of 60~80°, causing light leakage at a large viewing angle. With the development trend of integrated large screens (20 inches to 50 inches), the viewing angle of the main driver will range from 10° to 80°, so the wide-angle light leakage caused by the brightness enhancement film will seriously threaten the driver's safety. Summary of the invention

[0003] The present application provides a backlight module and a display device to improve the light leakage problem at a large viewing angle caused by a brightness enhancement film.

[0004] The present application provides a backlight module, comprising:

[0005] A back plate, comprising a bottom plate and side plates, wherein the bottom plate and the side plates are combined to form a receiving cavity;

[0006] An optical component is located in the accommodating cavity, and the optical component includes at least one first brightness enhancement film, and a plurality of first prisms are arranged on a side of the first brightness enhancement film away from the base plate, and the top angle of the first prism is greater than 90° and less than 105°, or the top angle of the first prism is rounded.

[0007] In one embodiment, when the top angle of the first prism is rounded, the radius of the rounded corner is R, and 0mm<R<17mm.

[0008] In one embodiment, the backlight module also includes an optical film layer, which is located on the side of the first brightness enhancement film away from the base plate, and the optical film layer includes at least one first refractive index layer and at least one second refractive index layer, the first refractive index layer and the second refractive index layer are stacked on each other, and the film layer of the optical film layer close to the first brightness enhancement film is the first refractive index layer, and the refractive index of the first refractive index layer is greater than the refractive index of the second refractive index layer.

[0009] In one embodiment, the optical component further comprises at least one second brightness enhancement film, and the second brightness enhancement film is located on a side of the first brightness enhancement film close to the bottom plate;

[0010] The first brightness enhancement film has a first side extending along a first direction and a second side extending along a second direction, and the first brightness enhancement film has a plurality of first prisms extending along a third direction and arranged along the second direction, and the angle between the third direction and the first direction is a first cutting angle a1, 0°≤a1<90°;

[0011] The second brightness enhancement film has a third side extending along the first direction and a fourth side extending along the second direction, and the second brightness enhancement film has a plurality of second prisms extending along the fourth direction and arranged along the first direction, and the included angle between the fourth direction and the first direction is a second cutting angle a2, 90°≤a2≤180°;

[0012] The first direction is perpendicular to the second direction, and the third direction intersects with the fourth direction.

[0013] In one embodiment, 30°≤a1≤60°, and 120°≤a2≤150°.

[0014] In one embodiment, the optical component also includes a reflective sheet, a light source and a diffusion film, the reflective sheet is located on a side of the base plate close to the accommodating cavity, the light source is located on a side of the reflective sheet away from the base plate, the diffusion film is located on a side of the light source away from the reflective sheet, and the first light-enhancing film is located on a side of the diffusion film away from the light source.

[0015] In one embodiment, the optical component also includes a reflective sheet, a light guide plate, a diffusion film and a light source, the reflective sheet is located on a side of the bottom plate close to the accommodating cavity, the light guide plate is located on a side of the reflective sheet away from the bottom plate, the diffusion film is located on a side of the light guide plate away from the reflective sheet, the first light enhancement film is located on a side of the diffusion film away from the light guide plate, and the light source is located between the light guide plate and the side plate.

[0016] The present application also provides a display device, comprising:

[0017] A backlight module, wherein the backlight module adopts the backlight module described in any of the above embodiments;

[0018] A first polarizer, located at the light-emitting side of the backlight module;

[0019] A display panel is located on a side of the first polarizer away from the backlight module;

[0020] The second polarizer is located on a side of the display panel away from the first polarizer.

[0021] In one embodiment, the display device further includes a third polarizer, which is located on a side of the second polarizer away from the display panel, wherein the display panel has a light emitting surface, and an absorption axis of the third polarizer is perpendicular to the light emitting surface.

[0022] In one embodiment, the display device further includes an anti-peep film, and the anti-peep film is disposed between the backlight module and the first polarizer, or is disposed on a side of the second polarizer away from the display panel.

[0023] The present application provides a backlight module and a display device, wherein the vertex angle of the first prism on the first light-enhancing film of the backlight module is greater than 90° and less than 105°, or the vertex angle of the first prism is rounded. Compared with the existing light-enhancing film structure with a prism vertex angle of 90°, the present application increases the vertex angle of the first prism on the first light-enhancing film, or rounds the vertex angle of the first prism, changes the refraction path of light, reduces the outgoing light at a large viewing angle, and thus improves the light leakage problem at a large viewing angle. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the embodiments or the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0025] Figure 1 A schematic cross-sectional structure diagram of a direct-type backlight module provided in an embodiment of the present application;

[0026] Figure 2 A schematic cross-sectional structure diagram of an edge-lit backlight module provided in an embodiment of the present application;

[0027] Figure 3 A cross-sectional schematic diagram of a first brightness enhancement film of a backlight module provided in an embodiment of the present application;

[0028] Figure 4A cross-sectional schematic diagram of a first brightness enhancement film when the vertex angle of a first prism of a backlight module provided by an embodiment of the present application is a rounded corner;

[0029] Figure 5 is a comparison diagram of the light path when the vertex angle of the first prism is rounded and the light path when the vertex angle of the prism is not rounded;

[0030] Figure 6 A schematic cross-sectional structure diagram of one of the backlight modules provided in the embodiments of the present application;

[0031] Figure 7 A schematic diagram of the structure of an optical film layer of a backlight module provided in an embodiment of the present application;

[0032] Figure 8 It is a schematic structural diagram of a first brightness enhancement film with a cutting angle of 0° and a second brightness enhancement film with a cutting angle of 90°;

[0033] Fig. 9 It is a schematic structural diagram of a first brightness enhancement film having a cutting angle of 45° and a second brightness enhancement film having a cutting angle of 135°;

[0034] Fig.10 for Figure 8 A full viewing angle distribution diagram of a backlight module corresponding to the structure;

[0035] Fig.11 for Fig. 9 A full viewing angle distribution diagram of a backlight module corresponding to the structure;

[0036] Fig.12 A schematic cross-sectional structure diagram of a display device provided in an embodiment of the present application;

[0037] Fig.13 A schematic diagram of the absorption axes of a third polarizer and a second polarizer of a display device provided in an embodiment of the present application and a diagram of simulation results;

[0038] Fig.14 A schematic cross-sectional structure diagram of another display device provided in an embodiment of the present application;

[0039] Fig.15 A schematic diagram of the cross-sectional structure of an anti-peep film of a display device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0040] 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.

[0041] In the description of the present application, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first" and "second" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0042] The present application may repeat reference numerals and / or reference letters in different embodiments. Such repetition is for the purpose of simplicity and clarity and does not in itself indicate the relationship between the various embodiments and / or settings discussed.

[0043] Please refer to Figure 1-Figure 4 The present application provides a backlight module 100, which includes a back plate 110 and an optical assembly 120. The back plate 110 includes a bottom plate 111 and a side plate 112, and the bottom plate 111 and the side plate 112 enclose a receiving cavity; the optical assembly 120 is located in the receiving cavity, and the optical assembly 120 includes at least one first brightness enhancement film (BEF) 121, and a plurality of first prisms 1211 are arranged on a side of the first brightness enhancement film 121 away from the bottom plate 111, and the vertex angle (i.e., vertex angle A) of the first prism 1211 is greater than 90° and less than 105°, such as Figure 3 As shown; or the top angle of the first prism 1211 is rounded, such as Figure 4 Compared with the existing brightness enhancement film structure with a prism vertex angle of 90°, the present application increases the vertex angle of the first prism 1211 on the first brightness enhancement film 121, or rounds the vertex angle of the first prism 1211, changes the refraction path of the light, and reduces the outgoing light at a large viewing angle, thereby effectively improving the light leakage problem at a large viewing angle.

[0044] Furthermore, the optical component 120 may also include one or more film layer structures including a reflective sheet 130, a diffusion film 150, a brightness enhancement film (DBEF) 123, a light source 160, a light guide plate 140, etc. The stacking order of each film layer can be set according to the specific structure of the backlight module 100, and is not limited here.

[0045] In one embodiment, if Figure 1As shown, the optical component 120 may further include a second brightness enhancement film 122, and the second brightness enhancement film 122 is located on a side of the first brightness enhancement film 121 close to the bottom plate 111. Figure 8 As shown, the first brightness enhancement film 121 has a first side L1 extending along the first direction X and a second side L2 extending along the second direction Y, and the first brightness enhancement film 121 has a plurality of first prisms 1211 extending along the third direction D1 and arranged along the second direction Y, and the angle between the third direction D1 and the first direction X is defined as a first cutting angle a1; the second brightness enhancement film 122 has a third side L3 extending along the first direction X and a fourth side L4 extending along the second direction Y, and the second brightness enhancement film 122 has a plurality of second prisms 1221 extending along the fourth direction D2 and arranged along the first direction X, and the angle between the fourth direction D2 and the first direction X is defined as a second cutting angle a2. Wherein, the first direction X is perpendicular to the second direction Y, and the third direction D1 intersects with the fourth direction D2.

[0046] Among them, Figure 8 As shown, the extension direction of the first prism 1211 of the first brightness enhancement film 121 and the extension direction of the second prism 1221 of the second brightness enhancement film 122 can be set perpendicularly. For example, the first cutting angle a1 of the first brightness enhancement film 121 can be 0°, and the second cutting angle a2 of the second brightness enhancement film 122 can be 90°, but it is not limited thereto.

[0047] It should be noted that there is no limitation on the vertex angle of the second prism 1221 provided on the second brightness enhancement film 122. The vertex angle of the second prism 1221 may be less than or equal to 90°, or greater than 90° and less than 105°, or the vertex angle of the second prism 1221 may be rounded.

[0048] In the present application, the backlight module 100 may be a direct-lit backlight module or an edge-lit backlight module, which is not limited herein.

[0049] like Figure 1 As shown, the backlight module 100 is a direct-type backlight module, and the optical component 120 may include a reflective sheet 130, a light source 160, a diffusion film 150 and a first light-enhancing film 121. The reflective sheet 130 is located on a side of the bottom plate 111 close to the accommodating cavity, the light source 160 is located on a side of the reflective sheet 130 away from the bottom plate 111, the diffusion film 150 is located on a side of the light source 160 away from the reflective sheet 130, and the first light-enhancing film 121 is located on a side of the diffusion film 150 away from the light source 160, but is not limited to this.

[0050] like Figure 2As shown, the backlight module 100 is an edge-entry backlight module, and the optical component 120 may include a reflective sheet 130, a light guide plate 140, a diffusion film 150, a first light enhancement film 121 and a light source 160. The reflective sheet 130 is located on a side of the bottom plate 111 close to the accommodating cavity, the light guide plate 140 is located on a side of the reflective sheet 130 away from the bottom plate 111, the diffusion film 150 is located on a side of the light guide plate 140 away from the reflective sheet 130, the first light enhancement film 121 is located on a side of the diffusion film 150 away from the light guide plate 140, and the light source 160 is located between the light guide plate 140 and the side plate 112, but is not limited thereto.

[0051] In one embodiment, if Figure 3 As shown, the vertex angle A of the first prism 1211 is greater than 90° and less than 105°. By increasing the vertex angle of the first prism 1211 on the first brightness enhancement film 121, the refraction path of the light can be changed, the outgoing light at a large viewing angle can be reduced, and the light leakage problem at a large viewing angle can be improved. Specifically, as Figure 1 As shown, taking a direct-type backlight module as an example, the backlight module 100 includes a back panel 110 and an optical component 120, the back panel 110 has a accommodating cavity, the optical component 120 is located in the accommodating cavity, the optical component 120 includes a reflective sheet 130, a light source 160, a diffusion film 150, a second light enhancement film 122, a first light enhancement film 121, and a brightness enhancement film (DBEF) 123 which are stacked in sequence, wherein the light source 160 can be a mini-LED.

[0052] The wide viewing angle light leakage improvement effect of the backlight module of this embodiment is further described below through comparative experiments, wherein the parameters of the first brightness enhancement film 121 and the second brightness enhancement film 122 of each comparative example and each embodiment and the corresponding horizontal viewing angle brightness ratio of the backlight module are shown in Table 1.

[0053] Table 1 Brightness enhancement film parameters and horizontal viewing angle brightness ratio of backlight module

[0054]

[0055]

[0056] From the comparison of the backlight horizontal viewing angle brightness ratio data at a wide viewing angle of 50° to 65° in Table 1, it can be seen that compared with the comparative example 1 in which the prism vertex angle of the brightness enhancement film is 90°, when the vertex angle of the first prism 1211 of the first brightness enhancement film 121 of Examples 1, 2 and 3 is set greater than 90°, the wide viewing angle light leakage of the backlight module is reduced, among which the effect of Example 3 is better, with less wide viewing angle light leakage.

[0057] In one embodiment, if Figure 4As shown, the top angle of the first prism 1211 is rounded. By setting the top angle of the first prism 1211 to be rounded, the refraction path of the light can be changed, the outgoing light at a large viewing angle can be reduced, and the light leakage problem at a large viewing angle can be improved. Further, when the top angle of the first prism 1211 is rounded, the radius of the rounded corner is R, 0mm<R<17mm, and when the radius of the rounded corner is greater than 17mm, the first prism 1211 is not easy to form.

[0058] like Figure 5 As shown, it is a comparison diagram of the light path when the top angle of the first prism is rounded and the light path when the top angle of the prism is not rounded, wherein the solid line is the light path when the top angle of the first prism 1211 is rounded, and the dotted line is the light path when the top angle of the first prism 1211 is not rounded. When the top angle of the first prism 1211 is set to be rounded, the refraction direction of the light can be changed, reducing the emission of light in the direction of a large viewing angle, thereby reducing light leakage at a large viewing angle.

[0059] In one embodiment, if Figure 6-Figure 7 As shown, the backlight module 100 further includes an optical film layer 170, which is located on the side of the first brightness enhancement film 121 away from the bottom plate 111. The optical film layer 170 includes at least one first refractive index layer 171 and at least one second refractive index layer 172. The first refractive index layer 171 and the second refractive index layer 172 are stacked with each other, and the film layer of the optical film layer 170 close to the first brightness enhancement film 121 is the first refractive index layer 171, and the refractive index of the first refractive index layer 171 is greater than the refractive index of the second refractive index layer 172. Further, the total number of layers of the first refractive index layer 171 and the second refractive index layer 172 ranges from 800 to 1000 layers. For example, the optical film layer 170 can be formed by stacking 1000 layers of the first refractive index layer 171 and the second refractive index layer 172. The first refractive index layer 171 and the second refractive index layer 172 can be resin films with nanometer thickness, but are not limited thereto.

[0060] like Figure 7 As shown, it is a schematic diagram of the structure of the optical film layer 170. The optical film layer 170 can be formed by stacking a first refractive index layer 171 with a high refractive index n1 and a second refractive index layer 172 with a low refractive index n2, where n1>n2. The optical film layer 170 uses the semi-reflective and semi-transmissive principle to achieve the transmission of incident light in the normal viewing direction of the film layer, and the reflection of incident light in the oblique viewing direction. In the present application, the optical film layer 170 can reflect the wide-angle light emitted from the surface of the first brightness enhancement film 121 multiple times, so that the wide-angle light changes direction and becomes a forward output, increasing the light output rate in the normal viewing direction, thereby reducing wide-angle light leakage.

[0061] The following comparative experiment further illustrates the wide-viewing angle light leakage improvement effect of the backlight module of this embodiment. The backlight module structure of the above-mentioned comparative example 2 is used as a basis. The backlight module of comparative example 2 is not provided with the optical film layer 170. Example 4 adds the optical film layer 170 on the basis of the backlight module structure of comparative example 2. The brightness ratio of the front and horizontal viewing angles of the backlight modules of comparative example 2 and example 4 is shown in Table 2.

[0062] Table 2 Brightness of the backlight module at front and horizontal viewing angles

[0063]

[0064] From the comparison of the horizontal viewing angle brightness data of the backlight module with a wide viewing angle of 50° to 65° in Table 2, it can be seen that the wide viewing angle light leakage of the backlight module is reduced in Example 4 in which the optical film layer 170 is provided as compared with the comparative example 2 in which the optical film layer 170 is not provided. Therefore, providing the optical film layer 170 on the first brightness enhancement film 121 can effectively improve the wide viewing angle light leakage problem caused by the brightness enhancement film.

[0065] In one embodiment, if Figure 8-Figure 9 As shown, the backlight module 100 includes a first brightness enhancement film 121 and a second brightness enhancement film 122, wherein the second brightness enhancement film 122 is located on a side of the first brightness enhancement film 121 close to the bottom plate 111, wherein the first brightness enhancement film 121 has a first cutting angle a1, and the second brightness enhancement film 122 has a second cutting angle a2, 0°≤a1<90°, 90°≤a2≤180°, and the stacking arrangement of multiple layers of brightness enhancement films is beneficial to improving the light output efficiency of the display device, and enhancing the display brightness and contrast.

[0066] In one embodiment, if Figure 8 As shown in FIG. 1 , the first cutting angle a1 of the first brightness enhancement film 121 is 0°, and the second cutting angle a2 of the second brightness enhancement film 122 is 90°. This structure is also a conventional first brightness enhancement film and second brightness enhancement film cutting angle setting structure in the prior art. However, under this structure, the backlight module still has large viewing angle light leakage under horizontal viewing angle (such as Fig.10 The white areas at both ends of the vertical direction in a) or the large viewing angle leakage under vertical viewing angle (such as Fig.10 (the white areas at both ends horizontally in b).

[0067] In one embodiment, if Fig. 9As shown, the first cutting angle a1 of the first brightness enhancement film 121 is in the range of 30°≤a1≤60°, and the second cutting angle a2 of the second brightness enhancement film 122 is in the range of 120°≤a2≤150°. In the present application, the cutting angles of the conventional first brightness enhancement film and the second brightness enhancement film are rotated clockwise or counterclockwise during the cutting process, so that the first cutting angle is no longer 0° and the second cutting angle is no longer 90°, so that the wide viewing angle light leakage is rotated to other angles, such as Fig.11 As shown, there is no large-viewing angle light leakage in the directions of the horizontal viewing angle and the vertical viewing angle, and therefore, the large-viewing angle light leakage within the driver's visible angle range can be reduced.

[0068] In one embodiment, if Fig. 9 The backlight module 100 includes a first light enhancement film 121 and a second light enhancement film 122. The second light enhancement film 122 is located on a side of the first light enhancement film 121 close to the bottom plate 111. The first cutting angle a1 of the first light enhancement film 121 is 45°, and the second cutting angle a2 of the second light enhancement film 122 is 135°. That is, the first cutting angle a1 of the first light enhancement film 121 is rotated from the existing 0° to 45°, and the second cutting angle a2 of the second light enhancement film 122 is rotated from the existing 90° to 45°. At this time, the wide-viewing angle light leakage of the backlight module is optimally improved.

[0069] The wide-viewing-angle light leakage improvement effect of the backlight module of this embodiment is further illustrated below through comparative experiments. Comparative Example 3 includes a first light enhancement film 121 (first cutting angle a1=0°) and a second light enhancement film 122 (second cutting angle a2=90°), and Example 5 includes a first light enhancement film 121 (first cutting angle a1=45°) and a second light enhancement film 122 (second cutting angle a2=135°). The brightness parameters of the backlight modules of Comparative Example 3 and Example 5 are shown in Table 3.

[0070] Table 3 Brightness parameters of backlight module

[0071] Benchmark Example Comparative Example 3 Example 5 Center brightness 311.2 / 324.8 Brightness ratio 100.0％ / 104.4％ Horizontal half intensity angle (degrees) 49.5 40.0 37.0 45° brightness ratio 59.4％ 43.4％ 38.5％ 50° brightness ratio 50％ 38.2％ 34％ 55° brightness ratio 41.3％ 34.3％ 29.9％ 60° Brightness Ratio 34.7％ 32.3％ 27.1％

[0072] The backlight module structure of the reference example only includes the first brightness enhancement film 121 (the first cutting angle a1=0°) and does not include the second brightness enhancement film 122 . The rest of the structure is the same as that of the comparative example 3.

[0073] The backlight module structure of Example 5 is obtained by rotating the cutting angles of the first brightness enhancement film 121 and the second brightness enhancement film 122 of Comparative Example 3 by 45°. It can be seen from the data in Table 3 that compared with Comparative Example 3, the wide-viewing angle light leakage of Example 5 is reduced. When the cutting angles of the first brightness enhancement film 121 and the second brightness enhancement film 122 are rotated by 45°, that is, the first cutting angle a1 of the first brightness enhancement film 121 is 45°, and the second cutting angle a2 of the second brightness enhancement film 122 is 135°, the wide-viewing angle light leakage can be reduced by about 4% to 6%.

[0074] Please refer to Fig.12 The present application also provides a display device, comprising: a backlight module 100, wherein the backlight module 100 adopts the backlight module 100 described in any of the above embodiments; a first polarizer 210, located on the light-emitting side of the backlight module 100; a display panel 200, located on the side of the first polarizer 210 away from the backlight module 100; and a second polarizer 220, located on the side of the display panel 200 away from the first polarizer 210.

[0075] Furthermore, the display device further includes a cover plate 300 , which is located on a side of the second polarizer 220 away from the display panel 200 .

[0076] In one embodiment, if Fig.12 As shown, the display device further includes a third polarizer 230 , which is located on a side of the second polarizer 220 away from the display panel 200 , and an absorption axis direction of the third polarizer 230 is perpendicular to a light emitting surface of the display panel 200 .

[0077] By combining the third polarizer 230 having an absorption axis in a vertical direction (i.e., the thickness direction of the third polarizer 230) and the second polarizer 220 placed on the display panel 200 to absorb light in a specific direction, light leakage at a large viewing angle can be reduced. Fig.13 As shown, the third polarizer 230 (vertical polarizer) has an absorption axis in the thickness direction, has no absorption axis when viewed from the front direction (a), and has the same direction as the observation angles (b) and (c) in the oblique directions when viewed from the oblique directions (b) and (c). When the third polarizer 230 and the second polarizer 220 are combined, the relationship between the two absorption axes is as follows: Fig.13 As shown in c. Fig.13 From the directions (a) and (b), the light is transmitted because the absorption axis of the second polarizer 220 is in a parallel Nicol state with the third polarizer 230; Fig.13 From the direction (c), the absorption axis of the second polarizer 220 and the absorption axis of the third polarizer 230 are in a crossed Nicol state, so the light is absorbed. Fig.13 As shown in middle d, the brightness distribution profile in the left and right directions becomes darker, and the light with a wide viewing angle is absorbed, thereby reducing light leakage with a wide viewing angle.

[0078] In one embodiment, if Fig.14 As shown, the display device further includes an anti-peep film 240, which is disposed between the backlight module 100 and the first polarizer 210, or disposed on a side of the second polarizer 220 away from the display panel 200. Fig.15 As shown, the privacy film 240 includes a substrate and an array-arranged microstructure 241 disposed in the substrate. The microstructure 241 is usually a black resin material that can absorb large-angle light. Therefore, the large-angle light emitted by the first brightness enhancement film 121 will be absorbed by the microstructure 241 in the privacy film 240 after passing through the privacy film 240, thereby improving the large-angle light leakage problem. Specifically, the microstructure 241 extends in a direction perpendicular to the light-emitting surface of the display panel 200, and is arranged in an array in a direction parallel to the light-emitting surface of the display panel 200. The cross-section of the microstructure 241 can be an inverted trapezoid, a rectangle, etc., which is not limited here.

[0079] Furthermore, the privacy film 240 is a wide-angle privacy film 240 , and the viewing angle range of the privacy film 240 is ±55° (that is, the viewing angle is 55° to 145°), which can reduce the light outside the viewing angle to 1%, thereby effectively reducing light leakage at a wide viewing angle.

[0080] The wide-angle light leakage improvement effect of the backlight module of this embodiment is further illustrated below through comparative experiments. The privacy film angle set in Example 6 is 140°, and the privacy film angle set in Example 7 is 90°. The brightness parameters of the backlight modules of Example 6 and Example 7 are shown in Table 4.

[0081] Table 4 Brightness parameters of the backlight modules of Example 6 and Example 7

[0082]

[0083]

[0084] It can be seen from the high-angle brightness ratio data in Table 4 that, compared with the high-angle brightness ratio data without the privacy film in the comparative example 1, the high-angle brightness ratio of the backlight module is reduced after the privacy film is used in Examples 6 and 7. Therefore, the privacy film 240 is provided on the light-emitting side of the backlight module to reduce light leakage at a large viewing angle. In this embodiment, relative to the requirement standard of the high-angle brightness ratio of the backlight module, the high-angle brightness ratio of the 90° privacy film in Example 7 is far from the requirement standard parameter. When the 140° privacy film is used in Example 6, not only the high-angle brightness ratio is reduced, but also it is closer to the requirement standard parameter, and the effect is better.

[0085] It should be noted that the display device may include at least one of the optical film layer 170 , the third polarizer 230 , and the anti-peep film 240 , and no specific limitation is made herein.

[0086] In summary, the present application provides a backlight module and a display device, wherein the vertex angle of the first prism on the first light-enhancing film of the backlight module is greater than 90° and less than 105°, or the vertex angle of the first prism is rounded. Compared with the existing light-enhancing film structure with a prism vertex angle of 90°, the present application increases the vertex angle of the first prism on the first light-enhancing film, or rounds the vertex angle of the first prism, thereby changing the refraction path of the light and reducing the outgoing light at a large viewing angle, thereby improving the light leakage problem at a large viewing angle.

[0087] In summary, although the present application has been disclosed as above with preferred embodiments, the above preferred embodiments are not intended to limit the present application. Ordinary technicians in this field can make various changes and modifications without departing from the spirit and scope of the present application. Therefore, the scope of protection of the present application shall be based on the scope defined in the claims.

Claims

1. A backlight module, characterized in that: include: A back plate, comprising a bottom plate and side plates, wherein the bottom plate and the side plates are combined to form a receiving cavity; An optical component is located in the accommodating cavity, and the optical component includes at least one first brightness enhancement film, and a plurality of first prisms are arranged on a side of the first brightness enhancement film away from the base plate, and the top angle of the first prism is greater than 90° and less than 105°, or the top angle of the first prism is rounded.

2. The backlight module according to claim 1, characterized in that: When the top angle of the first prism is rounded, the radius of the rounded corner is R, and 0mm<R<17mm.

3. The backlight module according to claim 1, characterized in that: The backlight module also includes an optical film layer, which is located on the side of the first brightness enhancement film away from the bottom plate. The optical film layer includes at least one first refractive index layer and at least one second refractive index layer. The first refractive index layer and the second refractive index layer are stacked on each other, and the film layer on the side of the optical film layer close to the first brightness enhancement film is the first refractive index layer, and the refractive index of the first refractive index layer is greater than the refractive index of the second refractive index layer.

4. The backlight module according to claim 1, characterized in that: The optical component further comprises at least one second brightness enhancement film, and the second brightness enhancement film is located on a side of the first brightness enhancement film close to the bottom plate; The first brightness enhancement film has a first side extending along a first direction and a second side extending along a second direction, and the first brightness enhancement film has a plurality of first prisms extending along a third direction and arranged along the second direction, and the angle between the third direction and the first direction is a first cutting angle a1, 0°≤a1<90°; The second brightness enhancement film has a third side extending along the first direction and a fourth side extending along the second direction, and the second brightness enhancement film has a plurality of second prisms extending along the fourth direction and arranged along the first direction, and the included angle between the fourth direction and the first direction is a second cutting angle a2, 90°≤a2≤180°; The first direction is perpendicular to the second direction, and the third direction intersects with the fourth direction.

5. The backlight module according to claim 4, characterized in that: 30°≤a1≤60°, 120°≤a2≤150°.

6. The backlight module according to any one of claims 1 to 5, characterized in that: The optical component also includes a reflective sheet, a light source and a diffusion film. The reflective sheet is located on a side of the base plate close to the accommodating cavity, the light source is located on a side of the reflective sheet away from the base plate, the diffusion film is located on a side of the light source away from the reflective sheet, and the first brightness enhancement film is located on a side of the diffusion film away from the light source.

7. The backlight module according to any one of claims 1 to 5, characterized in that: The optical component also includes a reflective sheet, a light guide plate, a diffusion film and a light source, the reflective sheet is located on a side of the bottom plate close to the accommodating cavity, the light guide plate is located on a side of the reflective sheet away from the bottom plate, the diffusion film is located on a side of the light guide plate away from the reflective sheet, the first light enhancement film is located on a side of the diffusion film away from the light guide plate, and the light source is located between the light guide plate and the side plate.

8. A display device, characterized in that: include: A backlight module, wherein the backlight module adopts the backlight module according to any one of claims 1 to 7; A first polarizer, located at the light-emitting side of the backlight module; A display panel is located on a side of the first polarizer away from the backlight module; The second polarizer is located on a side of the display panel away from the first polarizer.

9. The display device according to claim 8, characterized in that: The display device further includes a third polarizer, which is located on a side of the second polarizer away from the display panel, wherein the display panel has a light emitting surface, and an absorption axis direction of the third polarizer is perpendicular to the light emitting surface.

10. The display device according to claim 8, characterized in that: The display device further includes an anti-peep film, which is disposed between the backlight module and the first polarizer, or disposed on a side of the second polarizer away from the display panel.

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