Backlight module and display apparatus

Abstract

The present application provides a backlight module and a display apparatus. A first dimming structure receives a light ray emitted by a light source, and controls the projection of the principal optical axis of a light ray emitted to a light guide plate on the light guide plate to be parallel to the arrangement direction of a plurality of first prism structures on a brightness enhancement film, and the orthographic projection of the principal optical axis of a light ray emitted from the light guide plate on the brightness enhancement film to be perpendicular to the extension direction of the first prism structures, the plurality of first prism structures on the brightness enhancement film being arranged in a first direction and extending in a second direction.

Description

Backlight module and display device

[0001] This application claims priority to Chinese Patent Application No. 202411604568.4, filed on November 11, 2024, the disclosure of which is incorporated herein by reference in its entirety. Technical Field

[0002] This application relates to, but is not limited to, the field of display technology, specifically to a backlight module and a display device. Background Technology

[0003] 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. Invention Overview

[0004] This application provides a backlight module and display device that can improve backlight brightness.

[0005] This application 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.

[0006] This application 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. Attached Figure Description

[0007] Figure 1 is a schematic diagram of 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 this application;

[0008] Figure 2 is a schematic diagram showing the curve relationship between the backlight brightness and the rotation angle of the prism structure provided in the embodiments of this application;

[0009] Figures 3A and 3B are schematic diagrams of the backlight module provided in the embodiments of this application;

[0010] Figure 4 is a schematic diagram of the optical path provided in an embodiment of this application;

[0011] Figure 5 is a schematic diagram showing the angle at which the extension direction of the first prism structure provided in the embodiment of this application is deflected relative to the positive direction;

[0012] Figures 6A and 6B are schematic diagrams showing the positional relationship between the first dimming structure and the light guide plate provided in the embodiments of this application;

[0013] Figure 7 is a schematic diagram of the first included angle and the second included angle provided in the embodiments of this application;

[0014] Figure 8 is a schematic diagram of the second dimming structure provided in an embodiment of this application;

[0015] Figures 9A to 9D are schematic diagrams of simulation results provided in the embodiments of this application.

[0016] Figure 10 is a schematic diagram of the structure of the display device provided in an embodiment of this application;

[0017] Figure 11 is a comparison diagram of backlight illuminance uniformity provided in the embodiments of this application. Embodiments of the present invention

[0018] The following is an overview of the subject matter described in detail herein, and this overview is not intended to limit the scope of the claims. To make the objectives, technical solutions, and effects of this application clearer and more explicit, the following describes this application in further detail with reference to the accompanying drawings and embodiments. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of this application. Furthermore, it should be understood that the specific embodiments described herein are only for illustration and explanation of this application and are not intended to limit this application. In this application, unless otherwise stated, directional terms such as "upper" and "lower" generally refer to the upper and lower positions of the device in actual use or operation, specifically the drawing directions in the accompanying drawings; while "inner" and "outer" refer to the outline of the device.

[0019] In this application, 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 two relatively parallel objects is less than 5°. Similarly, "equal" can mean 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.

[0020] 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 perpendicular emission of light according to the light emitted from the light guide plate, thereby improving the backlight brightness.

[0021] 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.

[0022] Figure 1 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 according to an embodiment of this application. Figure 2 is a schematic diagram showing the curve relationship between the backlight brightness and the rotation angle of the prism structure according to an embodiment of this application. In Figure 2, the horizontal axis represents the range of angle variation between the principal 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 principal 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 decrease significantly. It is understood that the angle λ that causes a significant decrease in backlight brightness can vary depending on the actual product.

[0023] To improve the problem of reduced backlight brightness caused by the rotation of the prism structure, this application provides a backlight module and a display device. Figures 3A and 3B are schematic diagrams of the backlight module provided in the embodiment of this application, and Figure 4 is a schematic diagram of the optical path provided in the embodiment of this application. 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.

[0024] 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.

[0025] 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.

[0026] 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.

[0027] 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 main optical axis of the emitted light emitted to the light guide plate 20 to be projected onto the light guide plate 20 (as shown by DA in Figures 3A to 3B) to be parallel to the first direction Dr1.

[0028] 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.

[0029] It should be noted that the angle between the extension direction of the first prism structure 101 and the positive direction changes before and after rotation. Figure 5 is a schematic diagram of the angle of deflection of the extension direction of the first prism structure 101 relative to the positive direction according to an embodiment of this application. 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.

[0030] Figures 6A and 6B are schematic diagrams showing the positional relationship between the first dimming structure and the light guide plate provided in the embodiments of this application, and Figure 7 is a schematic diagram showing the first included angle and the second included angle provided in the embodiments of this application. 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.

[0031] Optionally, the dimming unit 401 may be configured as a prism structure. Referring to FIG6A, 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.

[0032] 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.

[0033] The deflection angle of the principal optical axis of the emitted light rays to the light guide plate 20 can be controlled by the angle between the first side surface 401a and the light-incident end face of the light guide plate 20. As shown in Figure 7, 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 rays 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.

[0034] 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 can be obtained, thus maximizing the light utilization rate of the backlight.

[0035] 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.

[0036] 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.

[0037] Optionally, from a top-down view, the dimming unit 401 can be designed as a triangle.

[0038] 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.

[0039] 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.

[0040] Furthermore, the dimming unit 401 can also be configured as a lens structure or the like. As shown in 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.

[0041] Optionally, the optical lens may be encapsulated or bonded to the light-emitting side of the light source 30.

[0042] 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.

[0043] 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.

[0044] 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.

[0045] 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.

[0046] 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.

[0047] 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.

[0048] Please refer to Figures 3A and 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.

[0049] 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.

[0050] 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.

[0051] 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.

[0052] 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.

[0053] 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 refer to Figures 3A and 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°~50°) to improve the light energy utilization efficiency and output brightness of the backlight module.

[0054] 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.

[0055] Optionally, the second dimming structure 501 can be a pyramidal structure, a prism structure, etc. Figure 8 is a schematic diagram of the second dimming structure provided in this embodiment. Taking a pyramidal structure as an example, the second dimming structure 501 includes four side surfaces and a bottom surface. The four side surfaces share the same vertex, and the four side surfaces are connected to the four edges of the bottom surface. This allows light incident on the second dimming structure 501 to converge the light emitted to the prism sheet 10 within a specific azimuth angle range. This enables the light to match the preferred incident angles corresponding to the first prism structure 101 and the second prism structure 102, increasing the proportion of light directly emitted when passing through the prism sheet 10, and improving the light energy utilization and brightness of the backlight module.

[0056] 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.

[0057] 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.

[0058] 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.

[0059] The second dimming structure 501 can be a protruding structure on the second substrate or a recessed structure within the second substrate.

[0060] 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.

[0061] Optionally, the second dimming structure 501 and the third prism structure 502 can be integrated with the second substrate.

[0062] Optionally, please continue to refer to 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 emission 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.

[0063] 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°.

[0064] 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.

[0065] 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.

[0066] Please refer to Figures 3A-3B. The side of the light guide plate 20 near the prism sheet 10 includes a fifth dimming structure 202. 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.

[0067] 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).

[0068] Optionally, the fifth dimming structure 202 may be integrally designed with the third substrate.

[0069] Please refer to 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.

[0070] 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, as shown in Figure 4.

[0071] Figures 9A to 9D are schematic diagrams of simulation results provided in the embodiments of this application. In Figures 9A and 9D, L1 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; in Figures 9B and 9D, L2 represents the simulation results of the backlight module when the prism structure on the prism sheet 10 is rotated and the first dimming structure 40 is not set; in Figures 9C and 9D, L3 represents the simulation results of the backlight module when the prism structure on the prism sheet 10 is rotated and the first dimming structure 40 is set; the horizontal axis in Figure 9D represents the viewing angle range, with the unit being degrees; the vertical axis represents the backlight brightness.

[0072] Please refer to Figures 9A-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 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.

[0073] Figure 10 is a schematic diagram of the structure of the display device provided in the embodiment of this application. This application also provides a display device DiD, including any of the above-mentioned backlight modules BL.

[0074] 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.

[0075] Optionally, the display panel DP includes a liquid crystal display panel, a quantum dot display panel, etc.

[0076] 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.

[0077] Figure 11 is a comparison diagram of backlight illuminance uniformity provided in the embodiments of this application; wherein, Figure 11 does not change the distribution of the fourth dimming structure 201. L4 in Figure 11 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 not set; L5 in Figure 11 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; the horizontal axis of Figure 11 represents the horizontal position of the display area of ​​the display panel (i.e., the position corresponding to A-A' in Figure 10), and the unit of the position is millimeters; the vertical axis represents the illuminance. The center point of the display area can be located on the A-A' connecting line in Figure 10.

[0078] Although each area of ​​the display area has corresponding illuminance information, the first dimming structure 40 causes a deflection in the principal optical axis of the emitted light rays into the light guide plate 20, thus affecting the display uniformity of the left and right parts of the display area. Therefore, in actual verification, illuminance information along the horizontal direction A-A' in Figure 10 was extracted to verify the display uniformity of the left and right parts of the display area. The verification results show that the first dimming structure 40 has a small impact on backlight uniformity, and the display uniformity of the left and right parts of the display area is minimally affected. Although the illuminance in the right area of ​​Figure 11 is too high, the backlight uniformity can be optimized by adjusting the distribution of the fourth dimming structure 201.

[0079] Those skilled in the art should understand that modifications or equivalent substitutions can be made to the embodiments of this application without departing from the spirit and scope of this application, and such modifications or equivalent substitutions should all be covered within the scope of this application. The embodiments can be combined with each other, but will not be described in detail here.

[0080] This document uses specific examples to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the methods and core ideas of this application. 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 this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A backlight module, wherein, 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.

2. The backlight module according to claim 1, wherein, The first dimming structure includes a plurality of dimming sections. Each dimming section includes a first side surface for receiving light emitted by the light source and a second side surface that contacts the end face of the light-incident side of the light guide plate. The first side surface and the end face of the light-incident side of the light guide plate have a first angle. The projection of the principal optical axis of the emitted light on the light guide plate and the normal of the light-incident side of the light guide plate have a second angle. Wherein, the first included angle and the second included angle satisfy the following condition: sinα=nsin(α-θ); α represents the first included angle, θ represents the second included angle, and n represents the refractive index of the dimming part.

3. The backlight module according to claim 1, wherein, The first dimming structure includes an off-axis lens located on the light-emitting side of the light source.

4. The backlight module according to claim 3, wherein, The surface of the off-axis lens is a freeform surface.

5. The backlight module according to claim 3, wherein, The off-axis lens is disposed on the surface of the light source.

6. The backlight module according to claim 3, wherein, 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.

7. The backlight module according to any one of claims 1 to 6, wherein, 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.

8. The backlight module according to claim 7, wherein, 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.

9. The backlight module according to claim 8, wherein, 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.

10. The backlight module according to any one of claims 1 to 6, wherein, 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°.

11. The backlight module according to claim 10, wherein, 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.

12. The backlight module according to claim 10, wherein, The shape of the fourth dimming structure includes hemispherical, prism, or horseshoe shape.

13. The backlight module according to claim 7, wherein, The prism sheet includes a first prism sheet and a second prism sheet. The first prism sheet includes a plurality of first prism structures, and the second prism sheet includes a plurality of second prism structures. The first prism sheet is located on one side of the second prism sheet.

14. The backlight module according to claim 7, wherein, The first prism structure and the second prism structure are disposed on opposite sides of the same substrate.

15. The backlight module according to claim 2, wherein, Multiple dimming units are disposed adjacent to each other and at equal intervals on the light-incident surface of the light guide plate.

16. The backlight module according to claim 1, wherein, The backlight module also includes a reflective sheet located on the side of the light guide plate away from the prism sheet.

17. A display device, wherein, Includes a backlight module and a display panel as described in any one of claims 1 to 16, wherein the backlight module is configured to provide backlight to the display panel.

18. The display device according to claim 17, characterized in that, The display panel includes a liquid crystal display panel.

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