Backlight module and display device

Abstract

A backlight module and a display device. In the backlight module, dimming surfaces (223) corresponding to annular dimming portions (221) are all connected to the ends of light incident surfaces (222) corresponding to the annular dimming portions (221) distant from a physical center (220), and the acute included angles α are sequentially increased in the direction from the physical center (220) to an annular dimming portion (221) on the outer side; or dimming surfaces (223) corresponding to annular dimming portions (221) are all connected to the ends of light incident surfaces (222) corresponding to the annular dimming portions (221) close to a physical center (220), and the acute included angles α are sequentially increased in the direction from the physical center (220) to an annular dimming portion (221) on the outer side.

Description

Backlight module and display device 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] In recent years, virtual reality (English full name: Virtual Reality, abbreviated as: VR) technology has developed rapidly, and the market share of VR head-mounted displays has been growing. The increasingly realistic image display effects provide users with a brand new experience. Liquid crystal displays (English full name: Liquid Crystal Display, abbreviated as: LCD) are widely used in virtual reality for their high image quality and high brightness. In order to obtain a good viewing experience, VR-type LCD panels require ultra-high-resolution screens. However, as the resolution increases, the transmittance of the LCD panel decreases. At the same time, because the solid angle corresponding to the human eye pupil is small, only light with a specific brightness angle distribution can be captured by the observer. The current mainstream backlight module emits light concentrated in the direction toward the surface normal, which results in relatively low brightness of VR-type LCD panels at off-center fields of view, resulting in low light efficiency utilization of the backlight module in VR-type LCD displays. This problem needs to be solved urgently. Technical issues

[0003] The present application provides a backlight module and a display device, which can effectively solve the problem of low light efficiency utilization of the backlight module in the existing VR-type liquid crystal display. Technical Solutions

[0004] On the one hand, the present application provides a backlight module, which includes: a backlight source having a light-emitting side; an angle deflection film, which is arranged on the light-emitting side of the backlight source, and the angle deflection film is parallel to the backlight source; the angle deflection film includes a dimming layer, and the dimming layer includes a plurality of annular dimming parts arranged on the same horizontal plane, and the plurality of annular dimming parts have the same physical center; the annular dimming part includes a light incident surface and a dimming surface, the light incident surface is parallel to the backlight source, the dimming surface and the light incident surface have a preset acute angle, the dimming surface is arranged on the side of the light incident surface away from the backlight source, and the dimming surface is on the light incident surface. The orthographic projection on it covers the light incident surface; wherein, among the multiple annular dimming parts, the dimming surface corresponding to each annular dimming part is connected to the end of the light incident surface corresponding to it away from the physical center, and in the direction from the physical center to the outer side of the annular dimming part, the degree of the acute angle between the dimming surface and the light incident surface increases successively; or, among the multiple annular dimming parts, the dimming surface corresponding to each annular dimming part is connected to the end of the light incident surface corresponding to it close to the physical center, and in the direction from the physical center to the outer side of the annular dimming part, the degree of the acute angle between the dimming surface and the light incident surface increases successively.

[0005] Optionally, in a direction perpendicular to the backlight source, in any cross section of the annular dimming portion passing through the physical center, acute angles formed by the dimming surface and the light incident surface are the same.

[0006] Optionally, the shape of the orthographic projection of the edge of the annular dimming portion on the backlight source is a circle.

[0007] Optionally, in the direction perpendicular to the backlight source, the cross-section of the annular dimming portion passing through the physical center is a right triangle, and the right triangle includes a first straight side, a first hypotenuse and a second straight side, the first straight side corresponds to the light incident surface, and the first hypotenuse corresponds to the dimming surface, wherein, in the direction from the physical center to the outer side of the annular dimming portion, the cross-sections of the plurality of annular dimming portions form a plurality of the right triangles arranged in sequence, and in the plurality of the right triangles arranged in sequence, the lengths of the first straight sides are all equal, and the lengths of the second straight sides gradually increase; or, in the direction from the physical center to the outer side of the annular dimming portion, the cross-sections of the plurality of the annular dimming portions form a plurality of the right triangles arranged in sequence, and in the plurality of the right triangles arranged in sequence, the lengths of the second straight sides are all equal, and the lengths of the first straight sides gradually decrease.

[0008] Optionally, in each of the right-angled triangles, the length of the first straight side is greater than the length of the second straight side, and the ratio of the second straight side to the first straight side is less than 0.6.

[0009] Optionally, the outgoing light of the backlight source includes a first outgoing light, and the angle between the first outgoing light and the normal direction perpendicular to the backlight source is γ, wherein γ is -1°-1°, and the outgoing light emitted from the annular dimming portion after the first outgoing light is deflected by the annular dimming portion is the second outgoing light, and the angle between the second outgoing light and the normal direction of the backlight source is β, wherein the β corresponding to the multiple annular dimming portions arranged in sequence in the direction of the annular dimming portion from the physical center to the outside gradually increases, and β is 0°-13°, the refractive index of the annular dimming portion is n, the acute angle is α, and

[0010] Optionally, in the direction of the annular dimming portion toward the outside of the physical center, the angle difference between the β corresponding to the x-th and x+1-th annular dimming portions is greater than the angle difference between the β corresponding to the y-th and y+1-th annular dimming portions, where x>y≥1.

[0011] Optionally, in the direction of the annular dimming portion from the physical center toward the outside, the angle difference between β corresponding to two adjacent annular dimming portions is a, wherein 0.018°<a<0.25°.

[0012] Optionally, in the direction of the annular dimming portion from the physical center toward the outside, the cross sections of the plurality of annular dimming portions form z right triangles arranged in sequence, wherein 50≤z≤100.

[0013] Optionally, in the direction of the annular dimming portion from the physical center toward the outside, the lengths of multiple first straight edges are the same, and the lengths of multiple second straight edges gradually increase; wherein, in the direction of the annular dimming portion from the physical center toward the outside, the length difference between two adjacent second straight edges is b, 0.003mm<b<0.03mm.

[0014] Optionally, in the direction of the annular dimming portion from the physical center toward the outside, the lengths of multiple second straight edges are the same, and the lengths of multiple first straight edges gradually decrease; wherein, in the direction of the annular dimming portion from the physical center toward the outside, the length difference between two adjacent first straight edges is c, 0.04mm<c<2mm.

[0015] Optionally, the angle deflection film also includes a substrate, the substrate is arranged on the light-emitting side of the backlight source, the dimming layer is arranged on the side of the substrate away from the backlight source, and the light incident surface is adjacent to the surface of the substrate on the side away from the backlight source, and the refractive index of the substrate is different from the refractive index of the dimming layer.

[0016] Optionally, the refractive index of the substrate is greater than the refractive index of the dimming layer.

[0017] Optionally, the backlight source includes: a reflective sheet, a light-emitting unit array and a diffuser, the light-emitting unit array is arranged on one side of the reflective sheet, and the diffuser is arranged on a side of the light-emitting unit array away from the reflective sheet, wherein the side of the diffuser away from the light-emitting unit array is the light-emitting side.

[0018] Optionally, the backlight source includes: a light bar, a light guide plate and a prism film, the light bar is provided at at least one end of the light guide plate, and the prism film is provided on one side of the light guide plate, wherein the side of the prism film away from the light guide plate is the light output side.

[0019] On the other hand, the present application provides a display device, which includes two symmetrically arranged display modules, each display module including a display panel and any one of the backlight modules described above. Beneficial effects

[0020] The present application provides a backlight module and a display device, wherein the backlight module includes a backlight source and an angle deflection film, the backlight source has a light-emitting side, the angle deflection film is arranged on the light-emitting side of the backlight source, and the angle deflection film is parallel to the backlight source; the angle deflection film includes a dimming layer, the dimming layer includes a plurality of annular dimming parts arranged on the same horizontal plane, and the plurality of annular dimming parts have the same physical center; the annular dimming part includes a light incident surface and a dimming surface, the light incident surface is parallel to the backlight source, the dimming surface and the light incident surface have a preset acute angle, the dimming surface is arranged on the side of the light incident surface away from the backlight source, and the dimming surface The orthographic projection of the surface on the light incident surface covers the light incident surface; wherein, among the multiple annular dimming parts, the dimming surface corresponding to each annular dimming part is connected to the end of the corresponding light incident surface away from the physical center, and in the direction of the annular dimming part from the physical center to the outside, the degree of the acute angle between the dimming surface and the light incident surface increases successively; or, among the multiple annular dimming parts, the dimming surface corresponding to each annular dimming part is connected to the end of the corresponding light incident surface close to the physical center, and in the direction of the annular dimming part from the physical center to the outside, the degree of the acute angle between the dimming surface and the light incident surface increases successively. In the backlight module provided by the present application, since the dimming surfaces corresponding to the multiple annular dimming parts are connected to the end of the corresponding light incident surface away from the physical center, or the dimming surfaces corresponding to the multiple annular dimming parts are connected to the end of the corresponding light incident surface close to the physical center, and in the direction of the annular dimming part from the physical center to the outside, the degree of the acute angle between the dimming surface and the light incident surface increases successively, therefore, the outgoing light emitted through the annular dimming part that is farther away from the physical center can have a larger angle of deflection, thereby improving the brightness of the edge area of ​​the dimming layer and improving the light efficiency utilization rate of the backlight module. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] 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. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0022] FIG1 is a cross-sectional schematic diagram of a backlight module provided in Example 1 of the present application.

[0023] FIG2 is a schematic top view of the angle deflection film provided in Example 1 of the present application.

[0024] FIG3 is a schematic cross-sectional view of an angle deflection film provided in Example 1 of the present application.

[0025] FIG4 is a cross-sectional schematic diagram of another angle deflection film provided in Example 1 of the present application.

[0026] FIG5 is a simulation diagram of the distance between the dimming point and the physical center and β of the backlight module provided in the first embodiment of the present application.

[0027] FIG6 is a cross-sectional schematic diagram of a backlight source provided in Example 1 of the present application.

[0028] FIG7 is a cross-sectional schematic diagram of another backlight source provided in the first embodiment of the present application.

[0029] FIG8 is a schematic diagram showing a simulation of the main ray angle when a mini LED backlight source is used with an ordinary Fresnel lens in the related art.

[0030] FIG9 a is a schematic diagram of light pattern simulation at different positions of a backlight module including an angle deflection film provided in the first embodiment of the present application when using a mini LED backlight source.

[0031] FIG9 b is a schematic diagram of light pattern simulation corresponding to diagonal viewing angles at different positions of the backlight module including the angle deflection film provided in the first embodiment of the present application when using a collimated backlight source.

[0032] 9 c is a schematic diagram of light pattern simulation corresponding to vertical viewing angles at different positions of the backlight module including the angle deflection film provided in the first embodiment of the present application when using a collimated backlight source.

[0033] FIG10 is a schematic cross-sectional view of an angle deflection film provided in Example 2 of the present application.

[0034] FIG11 is a cross-sectional schematic diagram of another angle deflection film provided in Example 2 of the present application.

[0035] Description of the accompanying drawings: Backlight source 10; light-emitting side 101; reflective sheet 11; light-emitting unit array 12; diffuser 13; light bar 14; light guide plate 15; prismatic film 16; angle deflection film 20; substrate 21; dimming layer 22; physical center 220; annular dimming portion 221; light incident surface 222; dimming surface 223; right triangle 224; first straight side 225; second straight side 226; first hypotenuse 227; acute angle α; angle β between the second emitted light and the normal direction of the light-emitting side; Modes for Carrying Out the Invention

[0036] The technical solutions in the embodiments of the present application will be clearly and completely described 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, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without making creative work are within the scope of protection of the present application. In addition, it should be understood that the specific implementation methods described herein are only used to illustrate and explain the present application, and are not used to limit the present application. In the present application, unless otherwise specified, the directional words used, such as "upper" and "lower", generally refer to the upper and lower parts of the device in actual use or working state, specifically the drawing direction in the accompanying drawings; and "inside" and "outside" refer to the outline of the device.

[0037] The disclosure below provides many different embodiments or examples for realizing different structures of the present application. In order to simplify the disclosure of the present application, the components and settings of specific examples are described below. Of course, they are merely examples and are not intended to limit the present application. In addition, the present application may repeat reference numbers and / or reference letters in different examples. 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. In addition, examples of various specific processes and materials are provided in the present application, but a person of ordinary skill in the art will recognize the application of other processes and / or the use of other materials. Each of the following is described in detail. It should be noted that the order of description of the following embodiments is not intended to limit the preferred order of the embodiments.

[0038] Example 1

[0039] Figure 1 is a cross-sectional schematic diagram of the backlight module provided in Example 1 of the present application; Figure 2 is a top-view schematic diagram of the angle deflection film provided in Example 1 of the present application; Figure 3 is a cross-sectional schematic diagram of an angle deflection film provided in Example 1 of the present application; Figure 4 is a cross-sectional schematic diagram of another angle deflection film provided in Example 1 of the present application. In combination with Figures 1 to 4, embodiment 1 of the present application provides a backlight module, which includes a backlight source 10 and an angle deflection film 20, wherein the backlight source 10 has a light-emitting side 101; the angle deflection film 20 is arranged on the light-emitting side 101 of the backlight source 10, and the angle deflection film 20 is parallel to the backlight source 10; the angle deflection film 20 includes a dimming layer 22, and the dimming layer 22 includes a plurality of annular dimming portions 221 arranged on the same horizontal plane, and the plurality of annular dimming portions 221 have the same physical center 220; the annular dimming portion 221 includes a light incident surface 222 and a dimming surface 223, the light incident surface 222 is parallel to the backlight source 10, the dimming surface 223 has a preset acute angle α with the light incident surface 222, and the dimming surface 223 is arranged on the side of the light incident surface 222 away from the backlight source 10. , and the orthographic projection of the dimming surface 223 on the light incident surface 222 covers the light incident surface 222; wherein, among the multiple annular dimming parts 221, the dimming surface 223 corresponding to each annular dimming part 221 is connected to the end of the light incident surface 222 corresponding to it away from the physical center 220, and in the direction from the physical center 220 to the outer side of the annular dimming part, the degree of the acute angle α between the dimming surface 223 and the light incident surface 222 increases successively; or, among the multiple annular dimming parts 221, the dimming surface 223 corresponding to each annular dimming part 221 is connected to the end of the light incident surface 222 corresponding to it close to the physical center 220, and in the direction from the physical center 220 to the outer side of the annular dimming part, the degree of the acute angle α between the dimming surface 223 and the light incident surface 222 increases successively.

[0040] In the backlight module provided by the present application, when the dimming surface 223 corresponding to each of the multiple annular dimming parts 221 is connected to the end of the corresponding light incident surface 222 away from the physical center 220, since the dimming surface 223 and the light incident surface 222 have a preset acute angle α, each of the annular dimming parts 221 adjusts the light of the outgoing light of the backlight source 10 in the same way, and each of the annular dimming parts 221 is a contraction-type dimming structure, which can enable the backlight module to have a narrower field of view (English full name: Field of view, abbreviated as: FOV). On this basis, since the degree of the acute angle α between the dimming surface 223 and the light incident surface 222 increases successively in the direction from the physical center 220 to the outer annular dimming portion, the outgoing light emitted through the annular dimming portion 221 farther away from the physical center 220 can have a larger angle of deflection, thereby increasing the brightness of the edge area of ​​the dimming layer 22 and improving the light efficiency utilization rate of the backlight module.

[0041] In the backlight module provided by the present application, when the dimming surface 223 corresponding to each of the multiple annular dimming parts 221 is connected to the end of the corresponding light incident surface 222 close to the physical center 220, since the dimming surface 223 and the light incident surface 222 have a preset acute angle α, each of the annular dimming parts 221 adjusts the light of the outgoing light of the backlight source 10 in the same way, and each of the annular dimming parts 221 is a diffuse dimming structure, which can enable the backlight module to have a wider field of view angle. On this basis, since the degree of the acute angle α between the dimming surface 223 and the light incident surface 222 increases successively in the direction from the physical center 220 to the outer annular dimming portion, the outgoing light emitted through the annular dimming portion 221 farther away from the physical center 220 can have a larger angle of deflection, thereby increasing the brightness of the edge area of ​​the dimming layer 22 and improving the light efficiency utilization rate of the backlight module.

[0042] In some embodiments of the present application, in a direction perpendicular to the backlight source, in any cross section of the annular dimming portion 221 passing through the physical center 220 , the acute angle α formed by the dimming surface 223 and the light incident surface 222 is the same.

[0043] In the backlight module provided by the present application, since the acute angle α between the dimming surface 223 and the light incident surface 222 is the same in any cross section of the annular dimming portion 221 passing through the physical center 220 in the direction perpendicular to the backlight source, the dimming surface 223 can have the same deflection angle for the fixed-angle outgoing light of the backlight source 10 in any cross section of the annular dimming portion 221 passing through the physical center 220 in the direction perpendicular to the backlight source, and the polarization effect of the dimming surface 223 of the annular dimming portion 221 in each area can be consistent, which is beneficial to improving the brightness uniformity of each area of ​​the annular dimming portion 221. In addition, the manufacturing process of each annular dimming portion 221 can be kept consistent, which is beneficial to improving process efficiency.

[0044] In some embodiments of the present application, the shape of the orthographic projection of the edge of the annular dimming portion 221 on the backlight source is a circle.

[0045] In the related art, the display field of a VR-type liquid crystal display panel is a circular field of view adapted to the human eye. This application enables the backlight module to be adapted to the VR-type liquid crystal display panel by making the shape of the positive projection of the edge of the annular dimming portion 221 on the backlight source circular.

[0046] In some embodiments of the present application, in a direction perpendicular to the backlight source, the cross-section of the annular dimming portion 221 passing through the physical center 220 is a right triangle 224, and the right triangle 224 includes a first straight side 225, a first hypotenuse 227, and a second straight side 226, the first straight side 225 corresponds to the light incident surface 222, and the first hypotenuse 227 corresponds to the dimming surface 223, wherein, in the direction from the physical center 220 to the outer side of the annular dimming portion, the cross-sections of the plurality of annular dimming portions 221 form a plurality of right triangles 224 arranged in sequence, and in the plurality of right triangles 224 arranged in sequence, the lengths of the second straight sides 226 are all equal, and the lengths of the first straight sides 225 gradually decrease.

[0047] In the backlight module provided in the present application, in the direction perpendicular to the backlight source, the cross-section of the annular dimming portion 221 passing through the physical center 220 is a right triangle 224, the first straight edge 225 corresponds to the light incident surface 222, and the first hypotenuse 227 corresponds to the dimming surface 223, that is, the angle between the first straight edge 225 and the first hypotenuse 227 is the acute angle α.

[0048] In the backlight module provided by the present application, in the direction from the physical center 220 to the outer annular dimming portion, the cross-sections of the multiple annular dimming portions 221 form a plurality of right-angled triangles 224 arranged in sequence, that is, in the direction from the physical center 220 to the outer annular dimming portion, any two adjacent right-angled triangles 224 are adjacently arranged, and there is no spacing distance between any two adjacent right-angled triangles 224. This structure enables the outgoing light emitted from the light-emitting side 101 of the backlight source to pass through the dimming action of the annular dimming portion 221 before it can be emitted to the outside of the backlight module, thereby ensuring the comprehensive dimming of the dimming layer 22.

[0049] Secondly, since the lengths of the plurality of second straight sides 226 are the same in the direction of the annular dimming portion 221 from the physical center 220 to the outside, and the lengths of the plurality of first straight sides 225 gradually decrease, the contraction ability or divergence ability of each right triangle 224 on the outgoing light of the backlight source 10 gradually increases in the direction of the annular dimming portion 221 from the physical center 220 to the outside. That is, when the light adjustment mode of the right triangle 224 on the outgoing light of the backlight source 10 is the contraction type, the annular dimming portion 221 that is farther away from the physical center 220 has a greater effect on the backlight source 10. The contraction ability of the outgoing light is gradually enhanced, thereby enhancing the brightness of the backlight module farther away from the physical center 220, improving the problem of low brightness at the off-center field of view in the related art; when the light adjustment method of the right triangle 224 for the outgoing light of the backlight source 10 is divergent, the farther the position of the annular dimming part 221 from the physical center 220 is, the more the divergence ability of the outgoing light of the backlight source 10 is gradually enhanced, thereby enhancing the brightness of the backlight module farther away from the physical center 220, improving the problem of low brightness at the off-center field of view in the related art.

[0050] Specifically, as shown in FIG3 , in the backlight module provided by the present application, the first straight side 225 of each right triangle 224 is arranged on the side of its second straight side 226 away from the physical center 220. At this time, the light adjustment method of the right triangle 224 for the outgoing light of the backlight source 10 is a contraction type, and the corresponding display device has a small field of view angle, such as less than 90°. In this case, since the lengths of the plurality of first straight sides 225 gradually decrease in the direction of the annular dimming portion 221 from the physical center 220 toward the outside, the annular dimming portion 221 has a gradually stronger contraction ability for the outgoing light of the backlight source 10 as the position is farther from the physical center 220, thereby enhancing the brightness of the backlight module farther from the physical center 220, thereby improving the problem of low brightness at the off-center field of view existing in the related art.

[0051] Specifically, as shown in FIG4 , in the backlight module provided by the present application, the first straight side 225 of each right triangle 224 is arranged on the side of its second straight side 226 close to the physical center 220. In this case, the light adjustment method of the right triangle 224 for the light emitted from the backlight source 10 is divergent, and the corresponding display device has a large field of view angle, such as greater than 90°. In this case, since the lengths of the plurality of first straight sides 225 gradually decrease in the direction of the annular dimming portion 221 from the physical center 220 toward the outside, the annular dimming portion 221 has a gradually stronger divergent ability for the light emitted from the backlight source 10 as it is farther from the physical center 220, thereby enhancing the brightness of the backlight module farther from the physical center 220, thereby improving the problem of low brightness at the off-center field of view existing in the related art.

[0052] It should be noted that, in other embodiments of the present application, in the direction perpendicular to the backlight source, the cross-section of the annular dimming portion 221 passing through the physical center 220 can also be an obtuse triangle, and the obtuse triangle can still satisfy the situation where the positive projection of the dimming surface 223 on the light incident surface 222 covers the light incident surface 222.

[0053] In some embodiments of the present application, the angle deflection film 20 also includes a substrate 21, the substrate 21 is arranged on the light-emitting side 101 of the backlight source 10, the dimming layer 22 is arranged on the side of the substrate 21 away from the backlight source 10, and the light incident surface 222 is adjacent to the surface of the substrate 21 on the side away from the backlight source 10, and the refractive index of the substrate 21 is the same as or different from the refractive index of the dimming layer 22.

[0054] In the backlight module provided in the present application, when the refractive index of the substrate 21 is the same as the refractive index of the dimming layer 22, the substrate 21 and the dimming layer 22 can be prepared at the same time, so as to be integrally formed; when the refractive index of the substrate 21 is different from the refractive index of the dimming layer 22, the difference in the refractive index of the substrate 21 and the refractive index of the dimming layer 22 can be used to prevent the large-angle output light in the backlight source 10 (such as the light in the output light of the backlight source 10 that is nearly vertically incident on the substrate 21) from being emitted through the dimming layer 22, so as to achieve the purpose of filtering stray light.

[0055] Optionally, the refractive index of the substrate 21 is greater than the refractive index of the dimming layer 22. By making the refractive index of the substrate 21 greater than the refractive index of the dimming layer 22, the present application can achieve the above-mentioned purpose of filtering stray light.

[0056] In some embodiments of the present application, in each of the right triangles 224 , the length of the first straight side 225 is smaller than the length of the second straight side 226 , wherein the ratio of the first straight side 225 to the second straight side 226 is smaller than 0.6.

[0057] In the backlight module provided in the present application, the present application can effectively reduce the difficulty of manufacturing the annular dimming portion 221 by controlling the ratio of the straight side with a longer length to the straight side with a shorter length within a range of less than 0.6.

[0058] Moreover, since the straight edge with a longer length is the first straight edge 225, and the first straight edge 225 is in contact with the surface of the substrate 21, the present application can improve the stability of the annular dimming portion 221 and extend the service life of the backlight module by setting the length of the first straight edge 225 in contact with the surface of the substrate 21 to be longer.

[0059] In some embodiments of the present application, the outgoing light of the backlight source 10 includes a first outgoing light, and the angle between the first outgoing light and the normal direction perpendicular to the light-emitting side 101 is γ, wherein γ is -1°-1°, and the outgoing light emitted from the annular dimming portion 221 after the first outgoing light is deflected by the annular dimming portion 221 is the second outgoing light, and the angle between the second outgoing light and the normal direction of the light-emitting side 101 is β, wherein, in the direction of the annular dimming portion 221 from the physical center 220 toward the outside, the β corresponding to the annular dimming portions 221 arranged in sequence gradually increases, and β is 0°-13°, the refractive index of the annular dimming portion 221 is n, the acute angle is α, and

[0060] In the backlight module provided in the present application, the first emitted light is the light with the highest brightness among the emitted lights from a light source point on the light-emitting side of the backlight source. Under normal circumstances, the angle γ between the first emitted light and the normal direction of the light-emitting side 101 is 0°. Under special circumstances, due to the design of the backlight source, the first emitted light may be offset. In this case, the angle γ between the first emitted light and the normal direction of the light-emitting side 101 is an angle within the range [-1°, 1°] except 0°.

[0061] In the backlight module provided by the present application, the larger the angle β between the second emitted light and the normal direction of the light-emitting side 101, the stronger the deflection ability of the annular dimming portion 221 to the first emitted light. The present application gradually increases the β corresponding to the annular dimming portions 221 arranged in sequence in the direction of the annular dimming portions 221 from the physical center 220 toward the outside, so that the annular dimming portions 221 farther away from the physical center 220 have stronger deflection ability to the emitted light of the backlight source 10, thereby improving the backlight brightness of the edge area and enhancing the optical efficiency of the backlight module.

[0062] FIG5 is a simulation diagram of the distance between the dimming point and the physical center and β of the backlight module provided in the first embodiment of the present application. Referring to FIG5 , there is a parabolic distribution as shown in FIG5 between the distance between the second emitted light in the backlight module and the physical center 220 and the angle β between the second emitted light and the normal direction of the light-emitting side 101. The present application can improve the dimming efficiency of the annular dimming part 221 by controlling β within the range of 0°-13°. When the value of β is determined, the preset angle α can be adjusted according to Get the specific value of α.

[0063] In some embodiments of the present application, in the direction of the annular dimming portion 221 toward the outside of the physical center 220, the angle difference between the β corresponding to the x-th and x+1-th annular dimming portions 221 is greater than the angle difference between the β corresponding to the y-th and y+1-th annular dimming portions 221, where x>y≥1.

[0064] In the backlight module provided by the present application, it can be seen from Figure 5 that when β is in the range of 0°-12°, as β continues to increase, the slope of β and the distance between the second output light in the backlight module and the physical center 220 continues to increase. The present application makes the angle difference between the β corresponding to the x-th and x+1-th annular dimming sections 221 in the direction of the annular dimming section 221 toward the outside of the physical center 220 greater than the angle difference between the β corresponding to the y-th and y+1-th annular dimming sections 221. This can make the light deflection effect of each annular dimming section 221 of the dimming layer 22 of the present application more adapted to the parabola, thereby further improving the optical efficiency of the backlight module.

[0065] In some embodiments of the present application, in the direction of the annular dimming portion 221 from the physical center 220 toward the outside, the angle difference between β corresponding to two adjacent annular dimming portions 221 is a, wherein 0.018<a<0.25.

[0066] In the backlight module provided by the present application, in the direction of the annular dimming portion 221 from the physical center 220 toward the outside, the greater the angular difference a between the β corresponding to two adjacent annular dimming portions 221, the greater the difference in the deflection ability of the two adjacent annular dimming portions 221 for the output light of the backlight source 10. When the difference is greater than a certain threshold, a noticeable sawtooth gradient is likely to occur, affecting the optical effect of the backlight source 10; when the difference is less than a certain threshold, diffraction problems are likely to occur, which also reduces the optical effect of the backlight source 10. By controlling the angular difference a between the β corresponding to two adjacent annular dimming portions 221 within the range of 0.018-0.25, the present application can improve the optical utilization of the backlight module while ensuring the optical effect of the backlight module.

[0067] In some embodiments of the present application, in the direction of the annular dimming portion 221 from the physical center 220 toward the outside, the cross-sections of the plurality of annular dimming portions 221 form z right triangles 224 arranged in sequence, where 50≤z≤100.

[0068] In the backlight module provided by the present application, in the direction of the annular dimming portion 221 from the physical center 220 toward the outside, the more the annular dimming portions 221 there are, the finer the regional division of the dimming layer 22 will be, and the angle difference a between β corresponding to two adjacent annular dimming portions 221 will theoretically become smaller. However, too many annular dimming portions 221 will not only increase the difficulty of processing and manufacturing, but may also cause diffraction problems. Therefore, the present application can improve the optical utilization of the backlight module while ensuring the optical effect of the backlight module by controlling the number of the annular dimming portions 221 within the range of 50-100.

[0069] In some embodiments of the present application, in the direction of the annular dimming portion 221 from the physical center 220 toward the outside, the lengths of the plurality of second straight edges 226 are the same, and the lengths of the plurality of first straight edges 225 gradually decrease; wherein, in the direction of the annular dimming portion 221 from the physical center 220 toward the outside, the length difference between two adjacent first straight edges 225 is c, 0.04<c<2.

[0070] Specifically, since the refractive indices of the substrate 21 and the dimming layer 22 are both fixed, when the angle γ of the first outgoing light at a fixed angle to the normal direction perpendicular to the light-emitting side 101 is fixed and the length of the second straight edge 226 is fixed, the length of the first straight edge 225 is positively correlated with the magnitude of β. This application controls the length difference between two adjacent first straight edges 225 within a range of 0.04-2, thereby utilizing the length difference between two adjacent first straight edges 225 to control the angle difference a between β corresponding to two adjacent annular dimming sections 221, thereby achieving the purpose of controlling the light deflection capability of each annular dimming section 221 and more simply and efficiently improving the optical utilization of the backlight module.

[0071] In some embodiments of the present application, the backlight source 10 is a direct-lit backlight source 10. FIG6 is a cross-sectional schematic diagram of a backlight source 10 provided in Embodiment 1 of the present application. As shown in FIG6 , the backlight source 10 includes a reflective sheet 11, a light-emitting unit array 12, and a diffuser 13. The light-emitting unit array 12 is disposed on one side of the reflective sheet 11, and the diffuser 13 is disposed on a side of the light-emitting unit array 12 away from the reflective sheet 11. The side of the diffuser 13 away from the light-emitting unit array 12 serves as the light-emitting side 101.

[0072] Of course, the present application does not limit the type of the backlight source 10. For example, in other embodiments of the present application, the backlight source 10 may also be an edge-entry backlight source 10. FIG7 is a cross-sectional schematic diagram of another backlight source 10 provided in Embodiment 1 of the present application. As shown in FIG7 , the backlight source 10 includes: a light bar 14, a light guide plate 15, and a prism film 16. The light bar 14 is provided on at least one section of the light guide plate 15. The prism film 16 is provided on one side of the light guide plate 15, wherein the side of the prism film 16 away from the light guide plate 15 is the light-emitting side 101.

[0073] Table 1 is a performance comparison table of the backlight module provided in Example 1 of the present application and a backlight module including an ordinary Fresnel lens in the related art.

[0074] Table 1

[0075] Among them, the backlight sources used in the comparative example in Table 1 and Example 1 have the same size, both of which are 2.1 inches, and the type of backlight sources is the same; the optical component in the comparative example is an ordinary Fresnel lens with a focal length of 110 mm, an aperture of 40 mm, and a tooth height of 20 microns; the optical component in Example 1 is an angle deflection film.

[0076] As shown in Table 1, a backlight module containing a conventional Fresnel lens has a parfocal focal length, while the backlight module 10 of the present application, which includes the angle deflection film 20, has no focal length restrictions. A backlight module containing a conventional Fresnel lens uses parallel light or a point light source, while the backlight module 10 of the present application, which includes the angle deflection film 20, uses a surface light source. A backlight module containing a conventional Fresnel lens cannot achieve directional light control; however, the backlight module 10 of the present application, which includes the angle deflection film 20, can achieve directional light control. Assuming that the backlight module including ordinary Fresnel lens has a light efficiency of 1 when entering the human eye at the observation position when using a collimated backlight source, the backlight module 10 including the angle deflection film 20 of the present application can achieve a light efficiency of 2.25 when entering the human eye at the same observation position when using a collimated backlight source; Assuming that the backlight module including ordinary Fresnel lens has a light efficiency of 1 when entering the human eye at the observation position when using a mini LED backlight source, the backlight module 10 including the angle deflection film 20 of the present application can achieve a light efficiency of 2.25 when entering the human eye at the same observation position when using a mini LED backlight source. When using an LED backlight source, the light efficiency entering the human eye at the same observation position can reach 1.3; taking a pupil movement of 3mm as an example, the vertical field angle of the collimated backlight source of the backlight module including an ordinary Fresnel lens is only 43.8%; while the vertical field angle of the collimated backlight source of the backlight module 10 including the angle deflection film 20 of the present application is 66.1%; the diagonal field angle of the collimated backlight source of the backlight module including an ordinary Fresnel lens is only 29%; while the diagonal field angle of the collimated backlight source of the backlight module 10 including the angle deflection film 20 of the present application is 66.3%; the field angle of the mini LED backlight source of the backlight module including an ordinary Fresnel lens is only 67%; while the diagonal field angle of the mini LED backlight source of the backlight module 10 including the angle deflection film 20 of the present application is 80%.

[0077] In reality, ordinary Fresnel lenses prioritize the main light axis angle deflection requirements at the edge of the backlight module (e.g., a 10° deflection angle) by setting structural parameters such as focal length and tooth height. However, the main light axis angles at other locations in the backlight module, except for the edge, cannot be simultaneously met. Figure 8 is a schematic diagram of the simulation of the main light angle when a mini LED backlight source is paired with an ordinary Fresnel lens in the related art. Referring to Figure 8, it can be seen that when the backlight source is a mini LED backlight source, the main light deflection angles at different positions of the comparative backlight module (corresponding to curve B) can hardly meet the VR optical machine requirements (corresponding to curve A).

[0078] Table 2 is a data comparison table of the design requirements and measured values ​​of the backlight module provided in Example 1 of this application. It should be noted that due to process limitations (taking into account the depth-to-width ratio of the corrugated teeth of a single annular dimming portion 221, the ratio of the second straight edge 226 to the first straight edge 225 is less than 0.6), the design requirements of the backlight module corresponding to Table 2 are that the height of the annular dimming portion 221 within 10 mm from the center of the circle is 13 microns, and the height of the annular dimming portion 221 within 10 mm-20 mm from the center of the circle is 20 microns.

[0079] Table 2

[0080] It can be seen from Table 2 that in the backlight module provided in this application, at different positions from the center of the circle, the difference between the measured value of the main light angle and the design requirement value is within 0.3°.

[0081] Figure 9a is a schematic diagram of light pattern simulation at different positions of the backlight module including the angle deflection film provided in Example 1 of the present application when using a mini LED backlight source; Figure 9b is a schematic diagram of light pattern simulation at different positions corresponding to diagonal viewing angles of the backlight module including the angle deflection film provided in Example 1 of the present application when using a collimated backlight source; Figure 9c is a schematic diagram of light pattern simulation at different positions corresponding to vertical viewing angles of the backlight module including the angle deflection film provided in Example 1 of the present application when using a collimated backlight source. Referring to Figures 9a, 9b, and 9c, the angle deflection film 20 provided in the present application can deflect the main optical axis of the backlight source 10 at different positions, and the light pattern does not change significantly before and after the deflection, which can effectively meet the requirements of VR applications.

[0082] In a second aspect, an embodiment of the present application further provides a display device, comprising two symmetrically arranged display modules, each display module comprising a display panel and a backlight module as described above.

[0083] Example 2

[0084] Figure 10 is a cross-sectional view of an angle deflection film provided in Example 2 of the present application; Figure 11 is a cross-sectional view of another angle deflection film provided in Example 2 of the present application. In conjunction with Figures 1 and 6-11, Example 2 of the present application provides a backlight module and a display device. The backlight module includes a backlight source 10 and an angle deflection film 20, the backlight source 10 has a light-emitting side 101; the angle deflection film 20 is arranged on the light-emitting side 101 of the backlight source 10, and the angle deflection film 20 is parallel to the backlight source 10; the angle deflection film 20 includes a dimming layer 22, the dimming layer 22 includes a plurality of annular dimming parts 221 arranged on the same horizontal plane, and the plurality of annular dimming parts 221 have the same physical center 220; the annular dimming part 221 includes a light incident surface 222 and a dimming surface 223, the light incident surface 222 is parallel to the backlight source 10, the dimming surface 223 has a preset acute angle α with the light incident surface 222, the dimming surface 223 is arranged on the side of the light incident surface 222 away from the backlight source 10, and the dimming surface 223 is at the same level as the backlight source 10. The orthographic projection on the light incident surface 222 covers the light incident surface 222; wherein, among the plurality of annular dimming sections 221, the dimming surface 223 corresponding to each annular dimming section 221 is connected to the end of the light incident surface 222 away from the physical center 220, and the degree of the acute angle α between the dimming surface 223 and the light incident surface 222 increases in a direction from the physical center 220 to the outer annular dimming section; or, among the plurality of annular dimming sections 221, the dimming surface 223 corresponding to each annular dimming section 221 is connected to the end of the light incident surface 222 close to the physical center 220, and the degree of the acute angle α between the dimming surface 223 and the light incident surface 222 increases in a direction from the physical center 220 to the outer annular dimming section. The display device includes two symmetrically arranged display modules, each display module including a display panel and the above-mentioned backlight module.

[0085] It should be noted that the structure of the backlight module in Example 2 of the present application is similar to that of the backlight module in Example 1 of the present application. Example 2 of the present application will not be repeated for the same parts. The difference is that in the direction perpendicular to the backlight source, the cross-section of the annular dimming portion 221 through the physical center 220 is a right triangle 224, and the right triangle 224 includes a first straight side 225, a first hypotenuse 227 and a second straight side 226. The first straight side 225 corresponds to the light incident surface 222, and the first hypotenuse 227 corresponds to the dimming surface 223. In the direction from the physical center 220 to the outer side of the annular dimming portion, the cross-sections of the multiple annular dimming portions 221 form a plurality of right triangles 224 arranged in sequence. In the plurality of right triangles 224 arranged in sequence, the lengths of the first straight sides 225 are all equal, and the lengths of the second straight sides 226 gradually increase.

[0086] In the backlight module provided by the present application, since the lengths of the plurality of first straight sides 225 are the same in the direction of the annular dimming portion 221 from the physical center 220 toward the outside, the lengths of the plurality of second straight sides 226 gradually increase, so that in the direction of the annular dimming portion 221 from the physical center 220 toward the outside, the contraction ability or divergence ability of each right triangle 224 to the outgoing light of the backlight source 10 gradually increases, that is, when the light adjustment mode of the right triangle 224 to the outgoing light of the backlight source 10 is a contraction type, the farther the annular dimming portion 221 is from the physical center 220, the more it has to adjust the light. The contraction ability of the outgoing light of the backlight source 10 is gradually enhanced, thereby being able to enhance the brightness of the backlight module farther away from the physical center 220, improving the problem of low brightness at the off-center field of view existing in the related art; when the light adjustment method of the right triangle 224 for the outgoing light of the backlight source 10 is divergent, the farther the position of the annular dimming part 221 from the physical center 220 is, the more the divergence ability of the outgoing light of the backlight source 10 is gradually enhanced, thereby being able to enhance the brightness of the backlight module farther away from the physical center 220, improving the problem of low brightness at the off-center field of view existing in the related art.

[0087] As shown in FIG10 , in the backlight module provided by the present application, the first straight side 225 of each right triangle 224 is arranged on the side of its second straight side 226 away from the physical center 220. At this time, the light adjustment method of the right triangle 224 for the outgoing light of the backlight source 10 is a contraction type, and the corresponding display device has a small field of view angle, such as less than 90°. In this case, since the lengths of the plurality of second straight sides 226 gradually increase in the direction of the annular dimming portion 221 from the physical center 220 toward the outside, the annular dimming portion 221 has a gradually stronger contraction ability for the outgoing light of the backlight source 10 as it is farther away from the physical center 220, thereby enhancing the brightness of the backlight module farther away from the physical center 220, thereby improving the problem of low brightness at the off-center field of view existing in the related art.

[0088] As shown in FIG11 , in the backlight module provided by the present application, the first straight side 225 of each right triangle 224 is arranged on the side of its second straight side 226 close to the physical center 220. In this case, the light adjustment method of the right triangle 224 for the light emitted from the backlight source 10 is divergent, and the corresponding display device has a large field of view angle, such as greater than 90°. In this case, since the lengths of the plurality of second straight sides 226 gradually increase in the direction of the annular dimming portion 221 from the physical center 220 toward the outside, the annular dimming portion 221 further away from the physical center 220 has a gradually stronger divergent ability for the light emitted from the backlight source 10, thereby enhancing the brightness of the backlight module further away from the physical center 220, thereby improving the problem of low brightness at the off-center field of view existing in the related art.

[0089] In some embodiments of the present application, in each of the right triangles 224 , the length of the first straight side 225 is smaller than the length of the second straight side 226 , wherein the ratio of the first straight side 225 to the second straight side 226 is smaller than 0.6.

[0090] In some embodiments of the present application, the output light of the backlight source 10 includes a first output light, and the angle between the first output light and the normal direction perpendicular to the backlight source is γ, wherein γ is -1°-1°, and the output light emitted from the annular dimming portion 221 after the first output light is deflected by the annular dimming portion 221 is the second output light, and the angle between the second output light and the normal direction of the backlight source is β, wherein, in the direction of the annular dimming portion 221 from the physical center 220 toward the outside, the β corresponding to the annular dimming portions 221 arranged in sequence gradually increases, and β is 0°-13°.

[0091] In some embodiments of the present application, in the direction of the annular dimming portion 221 from the physical center 220 toward the outside, the cross-sections of the plurality of annular dimming portions 221 form x right triangles 224 arranged in sequence, where 50≤x≤100.

[0092] In some embodiments of the present application, in the direction of the annular dimming portion 221 from the physical center 220 toward the outside, the lengths of the plurality of first straight edges 225 are the same, and the lengths of the plurality of second straight edges 226 gradually increase; wherein, in the direction of the annular dimming portion 221 from the physical center 220 toward the outside, the length difference between two adjacent second straight edges 226 is b, and 0.003<b<0.03.

[0093] Specifically, because the refractive indices of the substrate 21 and the dimming layer 22 are both fixed, when the angle γ of the first emitted light at a fixed angle with the normal direction perpendicular to the backlight source is fixed and the length of the first straight side 225 is fixed, the length of the second straight side 226 is positively correlated with the magnitude of β. By controlling the length difference between two adjacent second straight sides 226 within the range of 0.003-0.03, the present application can utilize the length difference between two adjacent second straight sides 226 to control the angle difference a between β corresponding to two adjacent annular dimming sections 221, thereby achieving the purpose of controlling the light deflection capability of each annular dimming section 221 and more simply and efficiently improving the optical utilization of the backlight module.

[0094] In summary, the present application provides a backlight module and a display device, wherein the backlight module includes a backlight source and an angle deflection film, wherein the backlight source has a light-emitting side, the angle deflection film is arranged on the light-emitting side of the backlight source, and the angle deflection film is parallel to the backlight source; the angle deflection film includes a dimming layer, the dimming layer includes a plurality of annular dimming parts arranged on the same horizontal plane, and the plurality of annular dimming parts have the same physical center; the annular dimming part includes a light incident surface and a dimming surface, the light incident surface is parallel to the backlight source, the dimming surface and the light incident surface have a preset acute angle, and the dimming surface is arranged on the side of the light incident surface away from the backlight source, and The orthographic projection of the dimming surface on the light incident surface covers the light incident surface; wherein, among the multiple annular dimming parts, the dimming surface corresponding to each annular dimming part is connected to the end of its corresponding light incident surface away from the physical center, and in the direction from the physical center to the outer annular dimming part, the degree of the acute angle between the dimming surface and the light incident surface increases successively; or, among the multiple annular dimming parts, the dimming surface corresponding to each annular dimming part is connected to the end of its corresponding light incident surface close to the physical center, and in the direction from the physical center to the outer annular dimming part, the degree of the acute angle between the dimming surface and the light incident surface increases successively. In the backlight module provided by the present application, since the dimming surfaces corresponding to the multiple annular dimming parts are connected to the end of the corresponding light incident surface away from the physical center, or the dimming surfaces corresponding to the multiple annular dimming parts are connected to the end of the corresponding light incident surface close to the physical center, and in the direction of the annular dimming part from the physical center to the outside, the degree of the acute angle between the dimming surface and the light incident surface increases successively, therefore, the outgoing light emitted through the annular dimming part that is farther away from the physical center can have a larger angle of deflection, thereby improving the brightness of the edge area of ​​the dimming layer and improving the light efficiency utilization rate of the backlight module.

[0095] The above is a detailed introduction to a backlight module and a display device provided in the embodiments of the present application. Specific examples are used herein to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the method of the present application and its core idea. At the same time, for those skilled in the art, based on the ideas of the present application, there may be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as a limitation on the present application.

Claims

1. A backlight module, wherein: The backlight module comprises: A backlight source having a light emitting side; An angle deflection film is arranged on the light-emitting side of the backlight source, and the angle deflection film is parallel to the backlight source; the angle deflection film includes a dimming layer, and the dimming layer includes a plurality of annular dimming parts arranged on the same horizontal plane, and the plurality of annular dimming parts have the same physical center; the annular dimming part includes a light incident surface and a dimming surface, the light incident surface is parallel to the backlight source, the dimming surface and the light incident surface have a preset acute angle, the dimming surface is arranged on the side of the light incident surface away from the backlight source, and the orthographic projection of the dimming surface on the light incident surface covers the light incident surface; Among the plurality of annular dimming parts, the dimming surface corresponding to each annular dimming part is connected to the end of the corresponding light incident surface away from the physical center, and in the direction from the physical center to the outer annular dimming part, the degree of the acute angle between the dimming surface and the light incident surface increases successively; Or, among the multiple annular dimming parts, the dimming surface corresponding to each annular dimming part is connected to the end of the corresponding light incident surface close to the physical center, and in the direction from the physical center to the outer side of the annular dimming part, the degree of the acute angle between the dimming surface and the light incident surface increases successively.

2. The backlight module according to claim 1, wherein: In a direction perpendicular to the backlight source, in any cross section of the annular dimming portion passing through the physical center, the acute angles formed by the dimming surface and the light incident surface are the same.

3. The backlight module according to claim 2, wherein: The shape of the orthographic projection of the edge of the annular dimming portion on the backlight source is a circle.

4. The backlight module according to claim 3, wherein: In a direction perpendicular to the backlight source, a cross section of the annular dimming portion through the physical center is a right triangle, the right triangle includes a first straight side, a first hypotenuse, and a second straight side, the first straight side corresponds to the light incident surface, and the first hypotenuse corresponds to the dimming surface, wherein, In the direction from the physical center to the outer side of the annular dimming part, the cross sections of the plurality of annular dimming parts form a plurality of right triangles arranged in sequence, in which the lengths of the first straight sides are all equal, and the lengths of the second straight sides gradually increase; Or, in the direction of the annular dimming part from the physical center to the outside, the cross-sections of the multiple annular dimming parts form a plurality of right-angled triangles arranged in sequence, and in the plurality of right-angled triangles arranged in sequence, the lengths of the second straight sides are all equal, and the lengths of the first straight sides gradually decrease.

5. The backlight module according to claim 4, wherein: The angle deflection film also includes a substrate, which is arranged on the light-emitting side of the backlight source, the dimming layer is arranged on the side of the substrate away from the backlight source, and the light incident surface is adjacent to the surface of the substrate on the side away from the backlight source, and the refractive index of the substrate is different from the refractive index of the dimming layer.

6. The backlight module according to claim 5, wherein: The refractive index of the substrate is greater than the refractive index of the dimming layer.

7. The backlight module according to claim 4, wherein: In each of the right-angled triangles, the length of the first straight side is greater than the length of the second straight side, and the ratio of the second straight side to the first straight side is less than 0.

6.

8. The backlight module according to claim 7, wherein: The output light of the backlight source includes a first output light, the angle between the first output light and the normal direction perpendicular to the backlight source is γ, wherein γ is -1°-1°, the output light emitted from the annular dimming part after the first output light is deflected by the annular dimming part is the second output light, the angle between the second output light and the normal direction of the backlight source is β, wherein the β corresponding to the plurality of annular dimming parts arranged in sequence in the direction from the physical center to the outer side of the annular dimming part gradually increases, and β is 0°-13°, the refractive index of the annular dimming part is n, the acute angle is α, and 9. The backlight module according to claim 8, wherein: In the direction of the annular dimming unit from the physical center toward the outside, the angle difference between the β corresponding to the x-th and x+1-th annular dimming units is greater than the angle difference between the β corresponding to the y-th and y+1-th annular dimming units, where x>y≥1.

10. The backlight module according to claim 9, wherein: In the direction of the annular dimming portion from the physical center toward the outside, the angle difference between β corresponding to two adjacent annular dimming portions is a, wherein 0.018°<a<0.25°.

11. The backlight module according to claim 10, wherein: In the direction of the annular dimming portion from the physical center toward the outside, the cross sections of the plurality of annular dimming portions form z right triangles arranged in sequence, wherein 50≤z≤100.

12. The backlight module according to claim 10, wherein: In the direction of the annular dimming portion from the physical center toward the outside, the lengths of the plurality of first straight sides are all the same, and the lengths of the plurality of second straight sides gradually increase; Wherein, in the direction of the annular dimming portion from the physical center toward the outside, the length difference between two adjacent second straight sides is b, and 0.003mm<b<0.03mm.

13. The backlight module according to claim 10, wherein: In the direction of the annular dimming portion from the physical center toward the outside, the lengths of the plurality of second straight sides are all the same, and the lengths of the plurality of first straight sides gradually decrease; Wherein, in the direction of the annular dimming portion from the physical center toward the outside, the length difference between two adjacent first straight sides is c, and 0.04mm<c<2mm.

14. The backlight module according to claim 1, wherein: The backlight source includes: a reflective sheet, a light emitting unit array and a diffuser, wherein the light emitting unit array is arranged on one side of the reflective sheet, and the diffuser is arranged on a side of the light emitting unit array away from the reflective sheet, wherein the side of the diffuser away from the light emitting unit array is the light emitting side.

15. The backlight module according to claim 1, wherein: The backlight source includes: a light bar, a light guide plate and a prism film, wherein the light bar is arranged at at least one end of the light guide plate, and the prism film is arranged on one side of the light guide plate, wherein the side of the prism film away from the light guide plate is the light emitting side.

16. A display device, wherein: The display device includes two symmetrically arranged display modules, each display module includes a display panel and a backlight module, wherein the backlight module includes: A backlight source having a light emitting side; An angle deflection film is arranged on the light-emitting side of the backlight source, and the angle deflection film is parallel to the backlight source; the angle deflection film includes a dimming layer, and the dimming layer includes a plurality of annular dimming parts arranged on the same horizontal plane, and the plurality of annular dimming parts have the same physical center; the annular dimming part includes a light incident surface and a dimming surface, the light incident surface is parallel to the backlight source, the dimming surface and the light incident surface have a preset acute angle, the dimming surface is arranged on the side of the light incident surface away from the backlight source, and the orthographic projection of the dimming surface on the light incident surface covers the light incident surface; Among the plurality of annular dimming parts, the dimming surface corresponding to each annular dimming part is connected to the end of the corresponding light incident surface away from the physical center, and in the direction from the physical center to the outer annular dimming part, the degree of the acute angle between the dimming surface and the light incident surface increases successively; Or, among the multiple annular dimming parts, the dimming surface corresponding to each annular dimming part is connected to the end of the corresponding light incident surface close to the physical center, and in the direction from the physical center to the outer side of the annular dimming part, the degree of the acute angle between the dimming surface and the light incident surface increases successively.

17. The display device according to claim 16, wherein: In the direction perpendicular to the backlight source, the cross-section of the annular dimming portion passing through the physical center is a right triangle, and the right triangle includes a first straight side, a first hypotenuse, and a second straight side, the first straight side corresponds to the light incident surface, and the first hypotenuse corresponds to the dimming surface, wherein in the direction of the annular dimming portion from the physical center to the outside, the cross-sections of the plurality of annular dimming portions form a plurality of right triangles arranged in sequence, and in the plurality of right triangles arranged in sequence, the lengths of the first straight sides are all equal, and the lengths of the second straight sides gradually increase.

18. The display device according to claim 16, wherein: In the direction perpendicular to the backlight source, the cross-section of the annular dimming portion passing through the physical center is a right triangle, and the right triangle includes a first straight side, a first hypotenuse, and a second straight side, the first straight side corresponds to the light incident surface, and the first hypotenuse corresponds to the dimming surface, wherein in the direction of the annular dimming portion from the physical center to the outside, the cross-sections of the plurality of annular dimming portions form a plurality of right triangles arranged in sequence, and in the plurality of right triangles arranged in sequence, the lengths of the second straight sides are all equal, and the lengths of the first straight sides gradually decrease.

19. The display device according to claim 16, wherein: The backlight source includes: a reflective sheet, a light emitting unit array and a diffuser, wherein the light emitting unit array is arranged on one side of the reflective sheet, and the diffuser is arranged on a side of the light emitting unit array away from the reflective sheet, wherein the side of the diffuser away from the light emitting unit array is the light emitting side.

20. The display device according to claim 16, wherein: The backlight source includes: a light bar, a light guide plate and a prism film, wherein the light bar is arranged at at least one end of the light guide plate, and the prism film is arranged on one side of the light guide plate, wherein the side of the prism film away from the light guide plate is the light emitting side.

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