Backlight module and display device

Abstract

According to the backlight module and the display device, the first dimming structure receives the light emitted by the light source, and the projection of the main optical axis of the light emitted to the light guide plate on the light guide plate is controlled to be parallel to the arrangement direction of the multiple first prism structures on the prismatic lens; the orthographic projection of a main optical axis of light guided out by the light guide plate on the prismatic lens is perpendicular to the extending direction of the first prism structures, the multiple first prism structures on the prismatic lens are arranged in the first direction and extend in the second direction, and the first direction is perpendicular to the second direction. Therefore, the prismatic lens can vertically emit light rays according to the light rays guided out by the light guide sheet, and the backlight brightness is improved.

Description

Technical Field

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

[0002] The periodically arranged prism structure in the backlight module is prone to interference with the pixel arrangement of the display panel, which in turn causes moiré to appear on the display panel. The moiré phenomenon can be improved by rotating the prism structure of the prism sheet in the backlight module so that the extension direction of the prism structure is deflected by a certain angle compared to the positive direction. However, after the deflection, the angle between the extension direction of the prism structure and the light emitting direction of the light source is large, which will cause a significant attenuation of the backlight brightness. Summary of the invention

[0003] The embodiments of the present invention provide a backlight module and a display device, which can improve the backlight brightness.

[0004] An embodiment of the present invention provides a backlight module, including a prism sheet, a light guide plate, a light source and a first dimming structure. The prism sheet includes a plurality of first prism structures arranged along a first direction and extending along a second direction, wherein the first direction is perpendicular to the second direction. The light guide plate is located on one side of the prism sheet, and the light guide plate is used to guide light to the prism sheet, and the orthographic projection of the main optical axis of the light guided by the light guide plate on the prism sheet is perpendicular to the second direction. The light source is located on the light incident side of the light guide plate. The first dimming structure is located between the light source and the light incident side of the light guide plate, and the first dimming structure is used to receive the light emitted by the light source, and control the orthographic projection of the main optical axis of the light emitted to the light guide plate on the light guide plate to be parallel to the first direction.

[0005] Optionally, in some embodiments, the first dimming structure includes a plurality of dimming parts, the dimming part includes a first side surface for receiving the light emitted by the light source, and a second side surface in contact with the end surface of the light incident side of the light guide plate, the first side surface and the end surface of the light incident side of the light guide plate have a first angle, and the projection of the main optical axis of the outgoing light on the light guide plate and the normal of the light incident side of the light guide plate have a second angle. The first angle and the second angle satisfy the following condition: sinα=nsin(α-θ); α represents the first angle, θ represents the second angle, and n represents the refractive index of the dimming part.

[0006] Optionally, in some embodiments, the first dimming structure includes an off-axis lens located at a light emitting side of the light source.

[0007] Optionally, in some embodiments, the surface of the off-axis lens is a free-form surface.

[0008] Optionally, in some embodiments, the off-axis lens is disposed on a surface of the light source.

[0009] Optionally, in some embodiments, in a top view, the deflected lens has a first arc, a second arc, and a third arc connected between the first arc and the second arc, wherein the curvature of the first arc is not equal to the curvature of the second arc.

[0010] Optionally, in some embodiments, the prism sheet further includes a plurality of second prism structures arranged along the second direction and extending along the first direction, wherein the first prism structure is located on one side of the second prism structure.

[0011] Optionally, in some embodiments, the backlight module also includes a microstructure film, which is located between the light guide plate and the prism sheet. A second dimming structure is provided on a side of the microstructure film close to the prism sheet. The second dimming structure includes four side surfaces and a bottom surface. The four side surfaces have a same vertex, and one of the diagonals of the bottom surface is parallel to the first direction.

[0012] Optionally, in some embodiments, the microstructure film has a plurality of third prism structures arranged along the second direction and extending along the first direction on a side away from the prism sheet.

[0013] Optionally, in some embodiments, a side of the light guide plate away from the prism sheet includes a fourth dimming structure, and the fourth dimming structure is used to control the light output angle of the light guide plate to be between 60° and 80°.

[0014] Optionally, in some embodiments, a side of the light guide plate close to the prism sheet includes a fifth dimming structure, and the fifth dimming structure includes a plurality of fourth prism structures arranged along the second direction and extending along the first direction.

[0015] The present invention provides a display device, comprising any of the above-mentioned backlight modules and a display panel, wherein the backlight module is configured to provide backlight to the display panel.

[0016] The present application provides a backlight module and a display device, which enable a first dimming structure to receive light emitted by a light source, and control the projection of the main optical axis of the output light emitted to the light guide plate on the light guide plate to be parallel to the arrangement direction of multiple first prism structures on the prism sheet, and the orthographic projection of the main optical axis of the output light output by the light guide plate on the prism sheet is perpendicular to the extension direction of the first prism structure. The multiple first prism structures on the prism sheet are arranged along a first direction and extend along a second direction, and the first direction is perpendicular to the second direction, so that the prism sheet can realize vertical output of light according to the light output by the light guide sheet to improve the backlight brightness. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0018] Figure 1 is a schematic diagram of the angle between the extending direction of the rotated prism structure and the light emitting direction of the light source provided by an embodiment of the present invention;

[0019] Figure 2 is a schematic diagram of a curve relationship of backlight brightness changing with the rotation angle of the prism structure provided by an embodiment of the present invention;

[0020] Figure 3A to Figure 3B is a schematic structural diagram of a backlight module provided by an embodiment of the present invention;

[0021] Figure 4 is a schematic diagram of an optical path provided by an embodiment of the present invention;

[0022] Figure 5 is a schematic diagram of an angle at which the extension direction of the first prism structure provided by an embodiment of the present invention is deflected compared to the positive direction;

[0023] Figure 6A to Figure 6B is a schematic diagram of the positional relationship between the first dimming structure and the light guide plate provided in an embodiment of the present invention;

[0024] Figure 7 is a schematic diagram of a first angle and a second angle provided by an embodiment of the present invention;

[0025] Figure 8 is a schematic diagram of a second dimming structure provided by an embodiment of the present invention;

[0026] FIG. 9A to FIG. 9D It is a schematic diagram of simulation results provided by an embodiment of the present invention.

[0027] Fig.10 is a schematic structural diagram of a display device provided by an embodiment of the present invention;

[0028] Fig.11 It is a comparison diagram of backlight illumination uniformity provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0029] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention. In addition, it should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0030] In the present invention, 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 attached drawings; while "inside" and "outside" refer to the outline of the device. The term "multiple" and similar words mean two or more, unless otherwise clearly defined. The term "vertical" includes absolute verticality and approximate verticality. For example, when the angle between A and B is 90°, A and B are absolutely vertical; when the angle between A and B is any non-90° degree between 85° and 95°, A and B are relatively vertical. In addition, the term "parallel" includes absolute parallelism and approximate parallelism. In the case of relative parallelism, the angle between the two relatively parallel parts is less than 5°. Similarly, "equal" can be absolutely equal. Since there are process errors in the production process, absolute equality cannot be guaranteed, so errors or process assembly process fluctuations can be tolerated. The "equal" in this application can be nearly equal, for example, the calculated values ​​differ by no more than 5%, which can be considered as an equal relationship.

[0031] Specifically, there has always been a design requirement for high brightness and low power consumption in display devices. In the backlight module that provides a high-brightness solution for the display panel, the periodically arranged prism structure is prone to interference with the pixel arrangement of the display panel, resulting in moiré phenomenon on the display panel. Therefore, the prism structure on the prism sheet will be rotated according to the actual light effect to improve the moiré phenomenon. However, when the angle between the extension direction of the rotated prism structure and the light emitting direction of the light source is large, the backlight brightness will be greatly attenuated.

[0032] like Figure 1 is a schematic diagram of the angle between the extending direction of the rotated prism structure and the light emitting direction of the light source provided by an embodiment of the present invention, Figure 2 : is a schematic diagram of the curve relationship between the backlight brightness and the rotation angle of the prism structure provided by the embodiment of the present invention. Figure 2The horizontal axis in the figure represents the range of the angle between the main optical axis direction D1 of the light emitted by the light source and the extension direction D2 of the prism structure on the prism sheet, and the vertical axis represents the backlight brightness. There is an angle λ between the main optical axis direction D1 of the light emitted by the light source and the extension direction D2 of the prism structure on the prism sheet. When the angle λ is greater than 30°, the backlight brightness will be significantly reduced. It can be understood that the angle λ corresponding to the significant reduction in the backlight brightness may vary depending on the actual product.

[0033] In order to improve the problem of reduced backlight brightness caused by the rotation of the prism structure, the present application provides a backlight module and a display device. Figure 3A to Figure 3B is a schematic structural diagram of a backlight module provided by an embodiment of the present invention, Figure 4 Schematic diagram of the optical path provided by an embodiment of the present invention. The present application provides a backlight module, including a prism sheet 10 , a light guide plate 20 , a light source 30 and a first dimming structure 40 .

[0034] The prism sheet 10 includes a plurality of first prism structures 101 arranged along a first direction Dr1 and extending along a second direction Dr2 . The first direction Dr1 is perpendicular to the second direction Dr2 .

[0035] The light guide plate 20 is located at one side of the prism sheet 10 , and is used to guide light to the prism sheet 10 , and the orthographic projection of the main optical axis of the light guided by the light guide plate 20 on the prism sheet 10 is perpendicular to the second direction Dr2 .

[0036] The light source 30 is located at the light incident side of the light guide plate 20. Optionally, the light source 30 includes a plurality of light emitting devices, and the plurality of light emitting devices are arranged periodically. The light emitting devices include light emitting diodes, etc. Optionally, the light emitting diodes include micro light emitting diodes, sub-millimeter light emitting diodes, etc.

[0037] The first dimming structure 40 is located between the light source 30 and the light incident side of the light guide plate 20. The first dimming structure 40 is used to receive the light emitted by the light source 30 and control the orthographic projection (such as the projection of the main optical axis of the light emitted to the light guide plate 20) on the light guide plate 20. Figure 3A to Figure 3B DA in FIG. 1 is parallel to the first direction Dr1.

[0038] By setting a first dimming structure 40 between the light source 30 and the light guide plate 20, the outgoing light emitted from the light source 30 to the light guide plate 20 is deflected, so as to control the main optical axis of the outgoing light emitted to the light guide plate 20 to have its orthographic projection on the light guide plate 20 parallel to the first direction Dr1, and the main optical axis of the light emitted from the light guide plate 20 to have its orthographic projection on the prism sheet 10 perpendicular to the second direction Dr2, so that the light emitted from the prism sheet 10 can be perpendicular to the light-emitting side surface of the prism sheet 10, thereby improving the backlight lighting effect, thereby improving the backlight brightness, and improving the problem of reduced backlight brightness caused by the rotation of the prism structure.

[0039] It should be noted that, before and after the first prism structure 101 rotates, the angle between the extension direction of the first prism structure 101 and the positive direction will change. Figure 5 It is a schematic diagram of the angle at which the extension direction of the first prism structure 101 provided in an embodiment of the present invention is deflected compared to the positive direction. Taking the positive direction of the x-axis as the positive direction, before the first prism structure 101 rotates, the angle between the extension direction of the first prism structure 101 and the positive direction is 0° or 90°. After the first prism structure 101 rotates, the angle between the extension direction of the first prism structure 101 and the positive direction is 0°+β or 90°+β. Among them, β represents the angle of rotation of the first prism structure 101, that is, the angle between the extension direction of the first prism structure 101 before rotation and the extension direction after rotation; the extension direction of the first prism structure 101 after rotation corresponds to the second direction Dr2.

[0040] Figure 6A to Figure 6B is a schematic diagram of the positional relationship between the first dimming structure and the light guide plate provided in an embodiment of the present invention, Figure 7 Schematic diagram of the first angle and the second angle provided by the embodiment of the present invention. The first dimming structure 40 includes a plurality of dimming parts 401, and the dimming parts 401 are used to receive the light emitted by the light source 30 and control the main optical axis of the light to deflect.

[0041] Optionally, the dimming unit 401 may be configured as a prism structure. Fig. 6A The dimming unit 401 includes a first side surface 401a for receiving light emitted by the light source 30, a second side surface 401b in contact with the end surface of the light incident side of the light guide plate 20, and a second side edge 401c connected between the first side surface 401a and the second side surface 401b.

[0042] When the light emitted by the light source 30 is incident on the first dimming structure 40, the main optical axis of the light will be deflected, so that the main optical axis of the light emitted to the light guide plate 20 is also deflected compared to the design without the first dimming structure 40. When the main optical axis of the light emitted to the light guide plate 20 is perpendicular to the extension direction of the first prism structure 101, the light utilization rate of the backlight is the highest.

[0043] The deflection angle of the main optical axis of the light emitted to the light guide plate 20 can be controlled by the angle between the first side surface 401a and the end surface of the light incident side of the light guide plate 20. Figure 7 As shown, there is a first angle between the first side surface 401a and the end surface of the light incident side of the light guide plate 20, and there is a second angle between the projection of the main optical axis of the outgoing light on the light guide plate 20 and the normal line of the light incident side of the light guide plate 20. The first angle and the second angle satisfy the following condition: sinα=nsin(α-θ). α represents the first angle, θ represents the second angle, and n represents the refractive index of the dimming unit 401.

[0044] When the main optical axis of the light emitted to the light guide plate 20 is perpendicular to the extension direction of the first prism structure 101 (i.e., the orthographic projection of the main optical axis of the light emitted on the light guide plate 20 is parallel to the first direction Dr1), the light utilization rate of the backlight is the highest. Therefore, after the first prism structure 101 on the prism sheet 10 is rotated, the first direction Dr1 and the second direction Dr2 are correspondingly determined, as well as the angle between the extension direction of the first prism structure 101 before rotation and the extension direction after rotation, the main optical axis of the light emitted to the light guide plate 20 can be determined, thereby determining the second angle θ, and then according to the relationship between the first angle α and the second angle θ sinα=nsin(α-θ), the first angle α is obtained, thereby maximizing the light utilization rate of the backlight.

[0045] Optionally, in a direction from the side of the prism sheet 10 close to the light guide plate 20 to the side of the prism sheet 10 away from the light guide plate 20, the dimming portion 401 has a first size, the light guide plate 20 has a second size, and the first size is less than or equal to the second size.

[0046] Optionally, the first size is equal to the second size, so as to utilize the first dimming structure 40 to improve the utilization rate of the light emitted by the light source 30 .

[0047] Optionally, in a top view, the dimming unit 401 may be designed to be a triangle.

[0048] Optionally, in order to make the light emitted by the light source 30 be uniformly emitted into the light guide plate 20 , a plurality of dimming parts 401 may be adjacently and evenly spaced apart and disposed on the light incident side surface of the light guide plate 20 .

[0049] Optionally, in order to save the manufacturing process, the first dimming structure 40 and the light guide plate 20 may be integrated. The first dimming structure 40 may be manufactured by an injection molding process or a stamping process.

[0050] In addition, the dimming unit 401 may also be configured as a lens structure or the like. Figure 6B The dimming unit 401 is an optical lens with a free-form surface, and the optical lens can be a primary optical lens or a secondary optical lens. The optical lens can be disposed on the surface of the light source 30 to achieve deflection control of the light emitted by the light source 30.

[0051] Optionally, the optical lens may be encapsulated or bonded to the light emitting side of the light source 30 .

[0052] It should be noted that when the optical lens is a primary optical lens, the primary optical lens can be directly disposed on the light emitting side of the light source 30. When the optical lens is a secondary optical lens, the secondary optical lens can be disposed on a side of the primary optical lens away from the light source 30.

[0053] Optionally, the optical lens is an off-axis lens, that is, the first dimming structure 40 includes an off-axis lens located on the light-emitting side of the light source 30, so that the light emitted by the light source 30 can be adjusted to the deflection angle of the main optical axis after passing through the optical lens. It should be noted that an off-axis lens means that the axis of the lens is not located at the exact center, but is biased to one side.

[0054] Optionally, the surface of the deflected lens is a free-form surface, and the deflected lens is arranged on the surface of the light source 30 .

[0055] Optionally, in a top-down perspective, the deflection lens has a first arc, a second arc, and a third arc connected between the first arc and the second arc, wherein the curvature of the first arc is not equal to the curvature of the second arc, so that the light emitted by the light source 30 can adjust the deflection angle of the main optical axis after passing through the deflection lens.

[0056] It is understandable that the curved surface shape of the optical lens can still be determined according to the second direction Dr2, the principal optical axis of the light emitted to the light guide plate 20, and the second angle θ. In practical applications, the curved surface shape of the optical lens can be obtained through optical simulation.

[0057] Optionally, one of the dimming units 401 can be arranged corresponding to one of the light sources 30, so that after the light emitted by each of the light sources 30 is acted upon by the corresponding dimming unit 401, the main optical axis of the outgoing light emitted into the light guide plate 20 can be projected on the light guide plate 20 in parallel with the first direction Dr1, so as to optimize the efficiency of improving the backlight effect.

[0058] Please continue reading Figure 3A to Figure 3B The prism sheet 10 further includes a plurality of second prism structures 102 arranged along the second direction Dr2 and extending along the first direction Dr1. The first prism structure 101 is located on one side of the second prism structure 102, that is, the first prism structure 101 is located on the side of the second prism structure 102 close to or away from the light guide plate 20. By making the extension direction of the first prism structure 101 and the extension direction of the second prism structure 102 perpendicular to each other, a better light enhancement effect is achieved, and the light loss of the prism sheet 10 is reduced, thereby improving the light output brightness of the backlight module.

[0059] In addition, the extension direction of the first prism structure 101 and the extension direction of the second prism structure 102 are perpendicular to each other, and the preferred incident angles corresponding to the first prism structure 101 and the second prism structure 102 can also be perpendicular, so that more light can be directly emitted when passing through the prism sheet 10, thereby improving the light energy utilization rate and light output brightness of the backlight module. It should be noted that the preferred incident angle means that after the light is incident on the prism sheet 10 at the preferred incident angle, it can be directly emitted from the prism sheet 10 without reflection.

[0060] Optionally, the prism sheet 10 may include a first prism sheet 10A and a second prism sheet 10B, wherein the first prism sheet 10A includes a plurality of the first prism structures 101, and the second prism sheet 10B includes a plurality of the second prism structures 102. The first prism sheet 10A is located on a side of the second prism sheet 10B close to or away from the light guide plate 20.

[0061] Optionally, the first prism sheet 10A and the second prism sheet 10B further include first substrates, respectively, to respectively carry the first prism structure 101 and the second prism structure 102. It can be understood that the first substrate carrying the first prism structure 101 can be integrated with the first prism structure 101, and the first substrate carrying the second prism structure 102 can be integrated with the second prism structure 102.

[0062] Optionally, the first prism structure 101 and the second prism structure 102 may also be disposed on two opposite sides of the same substrate to reduce the number of film layers included in the backlight module.

[0063] In order to improve the problem that the light incident into the prism sheet 10 is reflected to the light incident side of the prism sheet 10, and the reflected light is incident into the prism sheet 10 again and is reflected in a cycle, or the reflected light is emitted at a larger angle, resulting in greater light loss and large-angle light leakage, the backlight module can also include a microstructure film 50. Please continue to refer to Figure 3A to Figure 3B The microstructure film 50 is located between the light guide plate 20 and the prism sheet 10. The microstructure film 50 is used to converge the light incident to the prism sheet 10 within a specific azimuth angle range (such as 40° to 50°) to improve the light energy utilization efficiency and light output brightness of the backlight module.

[0064] In order to enable the microstructure film 50 to converge the light incident on the prism sheet 10 within a specific azimuth angle range, a second dimming structure 501 is provided on a side of the microstructure film 50 close to the prism sheet 10 .

[0065] Optionally, the second dimming structure 501 may be a pyramid structure, a prism structure, etc. Figure 8 It is a schematic diagram of the second dimming structure provided by an embodiment of the present invention, and takes the second dimming structure 501 as a pyramid structure as an example for explanation, wherein the second dimming structure 501 includes four side surfaces and a bottom surface, and the four side surfaces have a same vertex, and the four side surfaces are connected to the four side edges of the bottom surface. In this way, after the light is incident on the second dimming structure 501, the light emitted to the prism sheet 10 can be converged within a specific azimuth range, so that the light can match the preferred incident angle corresponding to the first prism structure 101 and the second prism structure 102, thereby increasing the proportion of light directly emitted when passing through the prism sheet 10, and improving the light energy utilization rate and light output brightness of the backlight module.

[0066] Optionally, in order to further match the preferred incident angle corresponding to the prism structure on the prism sheet 10, increase the proportion of vertical light output from the light output side of the prism sheet 10, and enhance the backlight brightness, one of the diagonal lines on the bottom surface of the second dimming structure 501 is parallel to the first direction Dr1.

[0067] Optionally, the second dimming structure 501 is a regular quadrangular pyramid structure, so that the light emitted from the second dimming structure 501 to the prism sheet 10 is focused within a specific azimuth angle range, thereby improving the light energy utilization rate and light output brightness of the backlight module.

[0068] Optionally, the microstructure film 50 further includes a second substrate carrying the second dimming structure 501 , and a plurality of second dimming structures 501 are arrayed on the second substrate to regulate the light emitted from various locations of the light guide plate 20 to enhance the light emitting effect of the backlight module.

[0069] The second dimming structure 501 may be a protruding structure disposed on the second substrate, or may be a recessed structure disposed in the second substrate.

[0070] In order to reduce the angle of light emitted from the microstructure film 50, a third prism structure 502 is provided on the side of the microstructure film 50 away from the prism sheet 10, and multiple third prism structures 502 are arranged along the second direction Dr2 and extend along the first direction Dr1, so that the third prism structure 502 can be used to deflect and converge the light incident into the microstructure film 50 in the vertical direction, thereby reducing the angle of light emitted from the microstructure film 50, and further allowing more light to be emitted vertically from the light-emitting side of the prism sheet 10, thereby improving large-angle light leakage and reducing light loss, thereby improving the light efficiency and brightness of the backlight module.

[0071] Optionally, the second dimming structure 501 and the third prism structure 502 may be integrated with the second substrate.

[0072] Optionally, see Figure 3A to Figure 3B The side of the light guide plate 20 away from the prism sheet 10 includes a fourth dimming structure 201, and the fourth dimming structure 201 is used to control the light output angle of the light guide plate 20 to be between 60° and 80°, so that the light incident on the light guide plate 20 can be effectively emitted from the side of the light guide plate 20 close to the prism sheet 10, thereby improving the light efficiency and brightness of the backlight module.

[0073] Optionally, the fourth dimming structure 201 is used to control the light output angle of the light guide plate 20 to be equal to 60°, 61°, 65°, 68°, 70°, 72°, 75°, 78°, 79° or 80°.

[0074] Optionally, the shape of the fourth dimming structure 201 may be hemispherical, prism-shaped, horseshoe-shaped, etc. The light guide plate 20 may include a third substrate carrying the fourth dimming structure 201, the third substrate and the fourth dimming structure 201 may be integrally designed, and a plurality of fourth dimming structures 201 are distributed in an array. The material of the light guide plate 20 may include polycarbonate or polymethyl methacrylate, etc.

[0075] It should be noted that the light emission angle refers to the angle between the light emission direction and the plane normal direction.

[0076] Please continue reading Figure 3A to Figure 3B The side of the light guide plate 20 close to the prism sheet 10 includes a fifth dimming structure 202, and the fifth dimming structure 202 includes a plurality of fourth prism structures arranged along the second direction Dr2 and extending along the first direction Dr1, so as to control the azimuth angle of the light emitted from the side of the light guide plate 20 close to the prism sheet 10, improve large-angle light leakage and reduce light loss.

[0077] Optionally, in a direction parallel to the thickness of the light guide plate 20, the cross section of the fourth prism structure may be a triangle or the like. For example, in a direction parallel to the thickness of the light guide plate 20, the cross section of the fourth prism structure may also be a closed figure composed of straight lines and arcs (for example, the cross section of the fourth prism structure includes three straight lines, and any two straight lines are connected by arcs).

[0078] Optionally, the fifth dimming structure 202 may be integrally designed with the third substrate.

[0079] Please continue reading Figure 3A to Figure 3B The backlight module further includes a reflective sheet 60, which is located on a side of the light guide plate 20 away from the prism sheet 10, so as to reflect the light incident on the reflective sheet 60 into the light guide plate 20, thereby improving the light utilization efficiency.

[0080] It should be noted that the backlight module may further include a diffusion film 70, and the diffusion film 70 is located between the light guide plate 20 and the prism sheet 10. Figure 4 shown.

[0081] FIG. 9A to FIG. 9D Schematic diagram of simulation results provided by an embodiment of the present invention. Fig.9A and Fig.9D L1 is a schematic diagram of simulation results corresponding to the backlight module when the prism structure on the prism sheet 10 is not rotated and the first dimming structure 40 is not provided; Fig. 9B and Fig.9D L2 in the figure is a schematic diagram of the simulation result corresponding to the backlight module when the prism structure on the prism sheet 10 is rotated and the first dimming structure 40 is not provided; Fig. 9C and Fig.9D L3 is a schematic diagram of the simulation result corresponding to the backlight module after the prism structure on the prism sheet 10 is rotated and the first dimming structure 40 is set; Fig.9D The horizontal axis represents the viewing angle range, and the unit corresponding to the viewing angle range is degree; the vertical axis represents the backlight brightness.

[0082] Please continue reading FIG. 9A to FIG. 9D, when the angle between the extension direction of the first prism structure 101 and the positive direction is set to 0°, and the angle between the extension direction of the second prism structure 102 and the positive direction is set to 90°, the backlight brightness is 68,000 nits. When the angle between the extension direction of the first prism structure 101 and the positive direction is set to 15°, and the angle between the extension direction of the second prism structure 102 and the positive direction is set to 105°, the backlight brightness is reduced to 60,000 nits. When the angle between the extension direction of the first prism structure 101 and the positive direction is set to 15°, and the angle between the extension direction of the second prism structure 102 and the positive direction is set to 105°, and the backlight module includes a first dimming structure 40, and the first angle is calculated as 38° according to the relationship sinα=nsin(α-θ), the backlight brightness is 66,000 nits. Therefore, compared with the design in which the first dimming structure 40 is not provided after the prism structure on the prism sheet 10 is rotated, the design in which the first dimming structure 40 is provided after the prism structure on the prism sheet 10 is rotated can increase the backlight brightness by 10%. Therefore, including the first dimming structure 40 in the backlight module is beneficial to brightening the backlight.

[0083] Fig.10 is a schematic diagram of the structure of a display device provided by an embodiment of the present invention. The present application also provides a display device DiD, comprising any of the above-mentioned backlight modules BL.

[0084] In some embodiments, the display device DiD further includes a display panel DP, and the backlight module BL is configured to provide backlight to the display panel DP.

[0085] Optionally, the display panel DP includes a liquid crystal display panel, a quantum dot display panel, etc.

[0086] It can be understood that the display panel DP includes data lines, scan lines, pixels and other parts not shown, and the display device includes driving chips and other parts not shown.

[0087] Fig.11 is a backlight illumination uniformity comparison diagram provided by an embodiment of the present invention; wherein, Fig.11 The distribution of the fourth dimming structure 201 is not changed. Fig.11 L4 is a schematic diagram of the simulation result corresponding to the backlight module when the prism structure on the prism sheet 10 is rotated and the first dimming structure 40 is not provided; Fig.11 L5 is a schematic diagram of the simulation result corresponding to the backlight module after the prism structure on the prism sheet 10 is rotated and the first dimming structure 40 is set; Fig.11 The horizontal axis represents the horizontal position of the intercepted display panel display area (i.e., corresponding to Fig.10 The center point of the display area can be located at Fig.10On the A-A' connecting line.

[0088] Although all parts of the display area have corresponding illumination information, the main optical axis direction of the light emitted to the light guide plate 20 is deflected after the first dimming structure 40 is set, which will affect the display uniformity of the left and right parts of the display area. Fig.10 The A-A' in the horizontal direction intercepts the illumination information, and verifies the display uniformity of the left and right parts of the display area. The verification results show that after setting the first dimming structure 40, the influence on the backlight uniformity is small, and the display uniformity of the left and right parts of the display area is less affected. Fig.11 The illumination of the middle right area is relatively high, but the backlight uniformity can be optimized by adjusting the distribution of the fourth dimming structure 201 .

[0089] Specific examples are used herein to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A backlight module, characterized in that: include: A prism sheet, comprising a plurality of first prism structures arranged along a first direction and extending along a second direction, wherein the first direction is perpendicular to the second direction; a light guide plate, located at one side of the prism sheet, for guiding light to the prism sheet, and the orthographic projection of the main optical axis of the light guided by the light guide plate on the prism sheet is perpendicular to the second direction; A light source, located at the light incident side of the light guide plate; as well as The first dimming structure is located between the light source and the light incident side of the light guide plate, and is used to receive the light emitted by the light source and control the main optical axis of the outgoing light emitted to the light guide plate to have an orthographic projection on the light guide plate parallel to the first direction.

2. The backlight module according to claim 1, characterized in that: The first dimming structure includes a plurality of dimming parts, the dimming part includes a first side surface for receiving the light emitted by the light source, and a second side surface in contact with the end surface of the light incident side of the light guide plate, a first angle is formed between the first side surface and the end surface of the light incident side of the light guide plate, and a second angle is formed between the projection of the main optical axis of the emitted light on the light guide plate and the normal line of the light incident side of the light guide plate; Wherein, the first angle and the second angle satisfy the following conditions: sinα=nsin(α-θ); α represents the first angle, θ represents the second angle, and n represents the refractive index of the dimming unit.

3. The backlight module according to claim 1, characterized in that: The first dimming structure includes an off-axis lens located at the light emitting side of the light source.

4. The backlight module according to claim 3, characterized in that: The surface of the deflected lens is a free-form surface.

5. The backlight module according to claim 3, characterized in that: The off-axis lens is arranged on the surface of the light source.

6. The backlight module according to claim 3, characterized in that: In a top view, the deflected lens has a first arc, a second arc, and a third arc connected between the first arc and the second arc; The curvature of the first circular arc is not equal to the curvature of the second circular arc.

7. The backlight module according to any one of claims 1 to 6, characterized in that: The prism sheet further includes a plurality of second prism structures arranged along the second direction and extending along the first direction; Wherein, the first prism structure is located on one side of the second prism structure.

8. The backlight module according to claim 7, characterized in that: Also includes: A microstructure film is located between the light guide plate and the prism sheet. A second dimming structure is provided on a side of the microstructure film close to the prism sheet. The second dimming structure includes four side surfaces and a bottom surface. The four side surfaces have a same vertex. One of the diagonals of the bottom surface is parallel to the first direction.

9. The backlight module according to claim 8, characterized in that: A plurality of third prism structures arranged along the second direction and extending along the first direction are disposed on a side of the microstructure film away from the prism sheet.

10. The backlight module according to any one of claims 1 to 6, characterized in that: The side of the light guide plate away from the prism sheet includes a fourth dimming structure, and the fourth dimming structure is used to control the light output angle of the light guide plate to be between 60° and 80°.

11. The backlight module according to claim 10, characterized in that: The light guide plate comprises a fifth dimming structure on a side close to the prism sheet. The fifth dimming structure comprises a plurality of fourth prism structures arranged along the second direction and extending along the first direction.

12. A display device, characterized in that: It comprises the backlight module and the display panel as claimed in any one of claims 1 to 11, wherein the backlight module is configured to provide backlight to the display panel.

Images