Backlight module and display device

Abstract

This invention provides a backlight module and display device. By having a first dimming structure receive light emitted from a light source and controlling the projection of the principal optical axis of the light emitted to the light guide plate onto the light guide plate to be parallel to the arrangement direction of a plurality of first prism structures on the prism sheet, and the orthogonal projection of the principal optical axis of the light emitted from the light guide plate onto the prism sheet to be perpendicular to the extension direction of the first prism structures, the plurality of first prism structures on the prism sheet are arranged along a first direction and extend along a second direction, the first direction being perpendicular to the second direction, so that the prism sheet can achieve perpendicular emission of light according to the light emitted from the light guide plate, thereby improving the backlight brightness.

Description

Technical Field

[0001] This invention relates to the field of display technology, and more specifically to a backlight module and display device. Background Technology

[0002] The periodically arranged prism structure in the backlight module is prone to interference with the pixel arrangement of the display panel, resulting in moiré patterns on the display. Rotating the prism structure in the backlight module, deflecting its extension direction by a certain angle relative to the forward direction, can improve the moiré effect. However, after deflection, the angle between the extension direction of the prism structure and the light emission direction of the light source is large, leading to a significant decrease in backlight brightness. Summary of the Invention

[0003] This invention provides a backlight module and display device that can improve backlight brightness.

[0004] This 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, the first direction being perpendicular to the second direction. The light guide plate is located on one side of the prism sheet and is used to guide light towards the prism sheet. The principal optical axis of the light rays guided by the light guide plate is projected onto the prism sheet with a projection 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. The first dimming structure is used to receive light emitted by the light source and control the principal optical axis of the emitted light rays projected onto 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 sections. Each dimming section includes a first side surface for receiving light emitted from the light source and a second side surface that contacts the end face of the light-incident side of the light guide plate. A first angle is formed between the first side surface and the end face of the light-incident side of the light guide plate, and a second angle is formed between the projection of the principal optical axis of the emitted light onto the light guide plate and the normal to the light-incident side of the light guide plate. 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 section.

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

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

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

[0009] Optionally, in some embodiments, from a top-down view, the off-axis lens has a first arc, a second arc, and a third arc connecting the first arc and the second arc. The curvature of the first arc and the curvature of the second arc are not equal.

[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. The first prism structure is located on one side of the second prism structure.

[0011] Optionally, in some embodiments, the backlight module further includes a microstructure film located between the light guide plate and the prism sheet. The microstructure film has a second dimming structure on the side near the prism sheet. The second dimming structure includes four sides and a bottom surface. The four sides have the same vertex, and one diagonal of the bottom surface is parallel to the first direction.

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

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

[0014] Optionally, in some embodiments, the light guide plate includes a fifth dimming structure on the side near the prism sheet, the fifth dimming structure including 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 including any of the above-described backlight modules and a display panel, wherein the backlight module is configured to provide backlight to the display panel.

[0016] This application provides a backlight module and display device. By having a first dimming structure receive light emitted from a light source and controlling the projection of the principal optical axis of the emitted light emitted to the light guide plate onto the light guide plate to be parallel to the arrangement direction of a plurality of first prism structures on the prism sheet, and the orthogonal projection of the principal optical axis of the emitted light emitted from the light guide plate onto the prism sheet to be perpendicular to the extension direction of the first prism structure, the plurality of first prism structures on the prism sheet are arranged along a first direction and extend along a second direction, the first direction being perpendicular to the second direction, so that the prism sheet can achieve vertical emission of light according to the light emitted from the light guide plate, thereby improving the backlight brightness. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying 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 effort.

[0018] Figure 1 This is a schematic diagram showing the angle between the extension direction of the rotated prism structure and the light emission direction of the light source provided in the embodiment of the present invention.

[0019] Figure 2 This is a schematic diagram showing the curve relationship between the backlight brightness and the rotation angle of the prism structure, provided in an embodiment of the present invention.

[0020] Figures 3A-3B This is a schematic diagram of the backlight module provided in an embodiment of the present invention;

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

[0022] Figure 5 This is a schematic diagram showing the angle at which the extension direction of the first prism structure provided in this embodiment of the invention is deflected relative to the positive direction;

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

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

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

[0026] Figures 9A to 9D This is a schematic diagram of the simulation results provided in the embodiments of the present invention.

[0027] Figure 10 This is a schematic diagram of the structure of the display device provided in an embodiment of the present invention;

[0028] Figure 11 This is a comparison diagram of backlight illuminance uniformity provided in an embodiment of the present invention. Detailed Implementation

[0029] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Furthermore, it should be understood that the specific embodiments described herein are only for illustration and explanation of the present invention and are not intended to limit the present invention.

[0030] In this invention, unless otherwise stated, directional terms such as "upper" and "lower" generally refer to the upper and lower positions of the device in its actual use or working state, specifically the orientation shown in the accompanying drawings; while "inner" and "outer" refer to the outline of the device. The term "multiple" and similar terms indicate two or more unless otherwise explicitly defined. The term "perpendicular" includes absolute perpendicularity and approximate perpendicularity. For example, when the angle between A and B is 90°, A and B are absolutely perpendicular; when the angle between A and B is any degree between 85° and 95° that is not 90°, A and B are relatively perpendicular. Furthermore, the term "parallel" includes absolute parallelism and approximate parallelism. In the case of relative parallelism, the angle between the two relatively parallel elements is less than 5°. Similarly, "equal" can be absolutely equal. Due to process errors in the production process, absolute equality cannot be guaranteed. Therefore, errors or fluctuations in the manufacturing process can be tolerated. In this application, "equal" can mean nearly equal, for example, calculated values ​​differing by no more than 5%, which can be considered as an equal relationship.

[0031] Specifically, display devices have always had a design requirement for high brightness and low power consumption. 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 patterns on the display. Therefore, the prism structure on the prism sheet is rotated according to the actual light effect to improve the moiré effect. However, when the angle between the extension direction of the rotated prism structure and the light emission direction of the light source is large, it will lead to a significant decrease in backlight brightness.

[0032] like Figure 1 This is a schematic diagram showing the angle between the extension direction of the rotated prism structure and the light emission direction of the light source, provided in an embodiment of the present invention. Figure 2 This is a schematic diagram illustrating the curve relationship between backlight brightness and the rotation angle of the prism structure, as provided in an embodiment of the present invention. Figure 2The horizontal axis represents the range of the angle between the principal optical axis D1 of the light emitted by the light source and the extension direction D2 of the prism structure on the prism sheet, while the vertical axis represents the backlight brightness. There is an angle λ between the principal optical axis 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 decrease significantly. Understandably, the angle λ that causes a significant decrease in backlight brightness can vary depending on the actual product.

[0033] To address the issue of reduced backlight brightness caused by prism structure rotation, this application provides a backlight module and a display device. Figures 3A-3B This is a schematic diagram of the backlight module provided in an embodiment of the present invention. Figure 4 This is a schematic diagram of the optical path provided in an embodiment of the present invention. This 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, wherein the first direction Dr1 is perpendicular to the second direction Dr2.

[0035] The light guide plate 20 is located on one side of the prism sheet 10. The light guide plate 20 is used to guide light to the prism sheet 10, and the main optical axis of the light guided plate 20 is projected onto the prism sheet 10 in a perpendicular direction Dr2.

[0036] The light source 30 is located on the light-incident side of the light guide plate 20. Optionally, the light source 30 includes multiple light-emitting devices, which are arranged periodically. The light-emitting devices include light-emitting diodes (LEDs). Optionally, the LEDs include miniature LEDs, sub-millimeter LEDs, etc.

[0037] The first dimming structure 40 is located between the light source 30 and the light guide plate 20 on the light incident side. The first dimming structure 40 is used to receive the light emitted by the light source 30 and control the orthogonal projection of the principal optical axis of the emitted light rays onto the light guide plate 20 (e.g., the light emitted from the light source 30). Figures 3A-3B (As shown in DA) 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 emitted light from the light source 30 to the light guide plate 20 is deflected, thereby controlling the orthogonal projection of the principal optical axis of the emitted light to the light guide plate 20 onto the light guide plate 20 to be parallel to the first direction Dr1, and making the orthogonal projection of the principal optical axis of the light emitted from the light guide plate 20 onto 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 efficiency and increasing the backlight brightness, which can improve the problem of reduced backlight brightness caused by the rotation of the prism structure.

[0039] It should be noted that the angle between the extension direction of the first prism structure 101 and the positive direction will change before and after the first prism structure 101 is rotated. For example Figure 5 This is a schematic diagram showing the angle of deflection of the extension direction of the first prism structure 101 provided in this embodiment of the invention relative 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. Here, 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] Figures 6A-6B This is a schematic diagram showing the positional relationship between the first dimming structure and the light guide plate provided in an embodiment of the present invention. Figure 7 This is a schematic diagram of the first included angle and the second included angle provided in an embodiment of the present invention. The first dimming structure 40 includes a plurality of dimming units 401, which are used to receive the light emitted by the light source 30 and control the principal optical axis of the light to deflect.

[0041] Optionally, the dimming unit 401 can be configured as a prism structure. Please refer to [further details]. Figure 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 that contacts the end face of the light-incident side of the light guide plate 20, and a second side edge 401c connecting the first side surface 401a and the second side surface 401b.

[0042] When light emitted from the light source 30 is incident on the first dimming structure 40, the principal optical axis of the light rays is deflected, causing the principal optical axis of the outgoing light rays to the light guide plate 20 to also deflect compared to a design without the first dimming structure 40. The backlight has the highest light utilization rate when the principal optical axis of the outgoing light rays to the light guide plate 20 is perpendicular to the extension direction of the first prism structure 101.

[0043] The deflection angle of the principal optical axis of the emitted light rays reaching the light guide plate 20 can be controlled by the angle between the first side surface 401a and the end face of the light-incident side of the light guide plate 20. For example... Figure 7 As shown, there is a first angle between the first side surface 401a and the light-incident end face of the light guide plate 20, and a second angle between the projection of the principal optical axis of the emitted light onto the light guide plate 20 and the normal to the light-incident side of the light guide plate 20. The first and second angles 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] The backlight has the highest light utilization rate when the principal optical axis of the emitted light rays to the light guide plate 20 is perpendicular to the extension direction of the first prism structure 101 (i.e., the orthogonal projection of the principal optical axis of the emitted light rays onto the light guide plate 20 is parallel to the first direction Dr1). Therefore, by rotating the first prism structure 101 on the prism sheet 10 and determining the first direction Dr1 and the second direction Dr2, as well as the angle between the extension direction of the first prism structure 101 before and after rotation, the principal optical axis of the emitted light rays to the light guide plate 20 can be determined, thereby determining the second angle θ. 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, thus maximizing the light utilization rate of the backlight.

[0045] Optionally, the dimming part 401 has a first size and the light guide plate 20 has a second size in the direction from the side of the prism sheet 10 near the light guide plate 20 to the side of the prism sheet 10 away from the light guide plate 20, wherein 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 improve the utilization rate of the light emitted by the light source 30 by utilizing the first dimming structure 40.

[0047] Optionally, from a top-down view, the dimming unit 401 can be designed as a triangle.

[0048] Optionally, in order to ensure that the light emitted by the light source 30 can be uniformly emitted into the light guide plate 20, a plurality of dimming units 401 may be disposed adjacently and at equal intervals on the light-incident side surface of the light guide plate 20.

[0049] Optionally, to save on manufacturing steps, the first dimming structure 40 and the light guide plate 20 can be integrated as a single unit. The first dimming structure 40 can be manufactured using injection molding or embossing processes.

[0050] Furthermore, the dimming unit 401 can 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, which 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, it can be directly disposed on the light-emitting side of the light source 30. When the optical lens is a secondary optical lens, it can be disposed on the 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, after passing through the optical lens, achieves adjustment of the deflection angle of the principal optical axis. 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 offset to one side.

[0054] Optionally, the surface of the off-axis lens is a freeform surface, and the off-axis lens is disposed on the surface of the light source 30.

[0055] Optionally, from a top-down perspective, the off-axis lens has a first arc, a second arc, and a third arc connecting the first and second arcs. The curvatures of the first and second arcs are not equal, so that the light emitted from the light source 30, after passing through the off-axis lens, adjusts the deflection angle of the principal optical axis.

[0056] Understandably, the curved shape of the optical lens can still be determined based on the second direction Dr2, the principal optical axis of the emitted light rays to the light guide plate 20, and the second included angle θ. In practical applications, the curved shape of the optical lens can be obtained through optical simulation.

[0057] Optionally, a dimming unit 401 may be provided corresponding to a light source 30, so that after the light emitted by each light source 30 is acted upon by the corresponding dimming unit 401, the orthogonal projection of the principal optical axis of the emitted light into the light guide plate 20 can be parallel to the first direction Dr1, thereby optimizing the efficiency of backlight light effect improvement.

[0058] Please continue reading. Figures 3A-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 closer to or further away from the light guide plate 20. By making the extension direction of the first prism structure 101 perpendicular to the extension direction of the second prism structure 102, 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] Furthermore, the extension direction of the first prism structure 101 is perpendicular to the extension direction of the second prism structure 102, which also ensures that the preferred incident angles corresponding to the first prism structure 101 and the second prism structure 102 are perpendicular. This allows more light to exit directly after passing through the prism sheet 10, thereby improving the light energy utilization and brightness of the backlight module. It should be noted that the preferred incident angle refers to the angle at which light, after being incident on the prism sheet 10, can exit directly 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. The first prism sheet 10A includes a plurality of first prism structures 101, and the second prism sheet 10B includes a plurality of second prism structures 102. The first prism sheet 10A is located on the side of the second prism sheet 10B that is closer to or farther from the light guide plate 20.

[0061] Optionally, the first prism sheet 10A and the second prism sheet 10B further include a first substrate for supporting the first prism structure 101 and the second prism structure 102, respectively. It is understood that the first substrate supporting the first prism structure 101 may be integral with the first prism structure 101, and the first substrate supporting the second prism structure 102 may be integral with the second prism structure 102.

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

[0063] To improve the problem of light loss and large-angle light leakage caused by light incident on the prism sheet 10 being reflected back to the light-incident side of the prism sheet 10 and then being reflected again after being incident on the prism sheet 10, or by the reflected light exiting at a large angle, the backlight module can also include a microstructure film 50. Please continue reading. Figures 3A-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 focus the light incident on the prism sheet 10 within a specific azimuth angle (such as 40° to 50°) to improve the light energy utilization efficiency and light output brightness of the backlight module.

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

[0065] Optionally, the second dimming structure 501 can be a pyramidal structure, a prism structure, etc. For example... Figure 8 This is a schematic diagram of the second dimming structure provided in an embodiment of the present invention. Taking the second dimming structure 501 as a pyramidal structure as an example, the second dimming structure 501 includes four side surfaces and a bottom surface. The four side surfaces have the same vertex, and the four side surfaces are connected to the four sides of the bottom surface. In this way, after light is incident on the second dimming structure 501, the light emitted to the prism sheet 10 can be focused within a specific azimuth angle range, so that the light can match the preferred incident angles 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 emitted from the light-emitting side of the prism sheet 10, and improve the backlight brightness, one of the diagonals of 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 square 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 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 an array of multiple second dimming structures 501 are distributed on the second substrate to regulate the light emitted from various parts of the light guide plate 20 and improve the light output effect of the backlight module.

[0069] The second dimming structure 501 can be a protruding structure on the second substrate or a recessed structure within the second substrate.

[0070] To reduce the angle at which light exits 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. Multiple third prism structures 502 are arranged along the second direction Dr2 and extend along the first direction Dr1. The third prism structure 502 is used to deflect and converge the light incident on the microstructure film 50 in the vertical direction, thereby reducing the angle at which light exits from the microstructure film 50. This allows more light to exit vertically from the light-emitting side of the prism sheet 10, improving large-angle light leakage and reducing light loss, thus enhancing the luminous efficiency and brightness of the backlight module.

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

[0072] Alternatively, please continue reading Figures 3A-3B The side of the light guide plate 20 away from the prism sheet 10 includes a fourth dimming structure 201. 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 closer 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 polar 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 can be hemispherical, prism-shaped, horseshoe-shaped, etc. The light guide plate 20 may include a third substrate supporting the fourth dimming structure 201. The third substrate and the fourth dimming structure 201 may be integrally designed, and multiple fourth dimming structures 201 may be arranged in an array. The material used to fabricate the light guide plate 20 may include polycarbonate or polymethyl methacrylate, etc.

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

[0076] Please continue reading. Figures 3A-3B The light guide plate 20 includes a fifth dimming structure 202 on the side near the prism sheet 10. 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 near the prism sheet 10, improve large-angle light leakage and reduce light loss.

[0077] Optionally, in the direction parallel to the thickness of the light guide plate 20, the cross-section of the fourth prism structure can be a triangular shape or the like. For example, in the direction parallel to the thickness of the light guide plate 20, the cross-section of the fourth prism structure can also be a closed shape composed of straight lines and arcs (specifically, the cross-section of the fourth prism structure includes three straight lines, with each pair of straight lines connected by an arc).

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

[0079] Please continue reading. Figures 3A-3B The backlight module also includes a reflective sheet 60, which is located on the 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 and improve the light utilization efficiency.

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

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

[0082] Please continue reading. Figures 9A to 9DWhen 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 decreases 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°, 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 to be 38° according to the relationship sinα=nsin(α-θ), the backlight brightness is 66,000 nits. Therefore, compared to a design where the prism structure on the prism sheet 10 is rotated without the first dimming structure 40, a design where the prism structure on the prism sheet 10 is rotated and the first dimming structure 40 is provided can increase the backlight brightness by 10%. Therefore, including the first dimming structure 40 in the backlight module is beneficial for brightening the backlight.

[0083] Figure 10 This is a schematic diagram of the structure of a display device provided in an embodiment of the present invention. This application also provides a display device DiD, including 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] Understandably, the display panel (DP) includes data lines, scan lines, pixels, and other components not shown, while the display device includes driver chips and other components not shown.

[0087] Figure 11 This is a comparison diagram of backlight illuminance uniformity provided in an embodiment of the present invention; wherein, Figure 11 The distribution of the fourth dimming structure 201 remains unchanged. Figure 11 L4 in the diagram is a simulation result of the backlight module when the prism structure on the prism sheet 10 is rotated and the first dimming structure 40 is not set. Figure 11 L5 in the diagram is a simulation result diagram of the backlight module after the prism structure on the prism sheet 10 is rotated and the first dimming structure 40 is set. Figure 11 The horizontal axis represents the horizontal position of the captured display area of ​​the display panel (i.e., corresponding to...). Figure 10 The position of A-A' in the diagram is shown, with the unit of measurement in millimeters; the vertical axis represents illuminance. The center point of the display area can be located at... Figure 10On the A-A' connecting line.

[0088] Although each area of ​​the display area corresponds to illuminance information, the setting of the first dimming structure 40 causes a deflection in the principal optical axis direction of the emitted light rays into the light guide plate 20. This affects the display uniformity of the left and right sides of the display area. Therefore, in actual verification, along... Figure 10 The A-A' section extracts the illuminance information in the horizontal direction to verify 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 impact on backlight uniformity is small, and the display uniformity of the left and right parts of the display area is less affected. Although Figure 11 The illuminance in the right-hand area is too high, but the uniformity of backlight can be optimized by adjusting the distribution of the fourth dimming structure 201.

[0089] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A backlight module, characterized in that, include: A 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; A light guide plate, located on one side of the prism sheet, is used to guide light out of the prism sheet, and the orthographic projection of the principal optical axis of the light guided plate onto the prism sheet is perpendicular to the second direction; The light source is located on 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. It is used to receive the light emitted by the light source and control the main optical axis of the emitted light emitted to the light guide plate to be parallel to the first direction when projected onto the light guide plate. The first dimming structure includes multiple dimming sections, each including a first side for receiving light emitted from the light source and a second side that contacts the light-incident end face of the light guide plate. A first angle is formed between the first side and the light-incident end face of the light guide plate, and a second angle is formed between the projection of the principal axis of the emitted light onto the light guide plate and the normal to the light-incident side of the light guide plate. The first and second angles satisfy the condition: sinα = nsin(α - θ); where α represents the first angle, θ represents the second angle, and n represents the refractive index of the dimming section. Alternatively, the first dimming structure may include an off-axis lens located on the light-emitting side of the light source.

2. The backlight module according to claim 1, characterized in that, The surface of the off-axis lens is a freeform surface.

3. The backlight module according to claim 1, characterized in that, The off-axis lens is disposed on the surface of the light source.

4. The backlight module according to claim 1, characterized in that, From a top-down perspective, the off-axis lens has a first arc, a second arc, and a third arc connecting the first arc and the second arc; The curvature of the first arc is not equal to the curvature of the second arc.

5. The backlight module according to any one of claims 1 to 4, characterized in that, The prism sheet also includes a plurality of second prism structures arranged along the second direction and extending along the first direction; The first prism structure is located on one side of the second prism structure.

6. The backlight module according to claim 5, characterized in that, Also includes: A microstructure film is located between the light guide plate and the prism sheet. The microstructure film has a second dimming structure on the side near the prism sheet. The second dimming structure includes four sides and a bottom surface. The four sides have the same vertex. One diagonal of the bottom surface is parallel to the first direction.

7. The backlight module according to claim 6, characterized in that, The microstructure membrane has a plurality of third prism structures arranged along the second direction and extending along the first direction on the side away from the prism sheet.

8. The backlight module according to any one of claims 1 to 4, characterized in that, The side of the light guide plate away from the prism sheet includes a fourth dimming structure, which is used to control the light output angle of the light guide plate to be between 60° and 80°.

9. The backlight module according to claim 8, characterized in that, The light guide plate includes a fifth dimming structure on the side near the prism sheet, the fifth dimming structure including a plurality of fourth prism structures arranged along the second direction and extending along the first direction.

10. A display device, characterized in that, Includes a backlight module and a display panel as described in any one of claims 1 to 9, wherein the backlight module is configured to provide backlight to the display panel.

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