Backlight module and display equipment

Abstract

The utility model provides a backlight module and display equipment. The backlight module comprises at least one light source; the light guide plate comprises a light-in surface, a light-out surface and a bottom surface opposite to the light-out surface, and the light-in surface is located on the side, facing the light source, of the light guide plate; the diffusion sheet is located on the light-emitting surface side of the light guide plate and comprises a first surface and a second surface which are oppositely arranged, and the first surface is close to the light guide plate relative to the second surface; wherein the bottom surface and / or the first surface are / is a light adjusting surface, the light adjusting surface is provided with a plurality of light adjusting units, and the light adjusting units are configured to adjust light rays so that the light emitting angle of the diffusion sheet can be within a preset range. The backlight module has the advantages of being small in light emitting angle and high in center brightness.

Description

Technical Field

[0001] The utility model relates to the technical field of display, in particular to a backlight module and a display device. Background Art

[0002] With the development of electronic products, the application scenarios of display devices are gradually increasing, and the requirements for display devices in different application scenarios are different. For example, head-mounted display devices used in the field of near-eye display require smaller luminous power to prevent users from feeling dizzy due to smearing when wearing the head-mounted display devices. This means that a larger current is required to achieve the same backlight brightness with the same size and the same structure. As the current increases, the power consumption of the display device increases. Utility Model Content

[0003] The utility model aims to solve at least one of the technical problems existing in the prior art, and proposes a backlight module and a display device.

[0004] According to one aspect of the present invention, a backlight module is provided, comprising:

[0005] at least one light source;

[0006] a light guide plate, the light guide plate comprising a light incident surface, a light emitting surface, and a bottom surface arranged opposite to the light emitting surface, the opposite ends of the light incident surface being connected to the light emitting surface and the bottom surface, respectively, and the light incident surface being located on a side of the light guide plate facing the light source;

[0007] a diffuser, the diffuser being located on the light-emitting surface side of the light guide plate, the diffuser comprising a first surface and a second surface oppositely disposed, the first surface being closer to the light guide plate than the second surface;

[0008] The bottom surface and / or the first surface is a dimming surface having a plurality of dimming units, and the dimming units are configured to adjust the light so that the light output angle of the diffuser is within a preset range.

[0009] In some optional embodiments, when the bottom surface is the dimming surface, the dimming unit on the bottom surface is a first dimming unit, and at least two of the multiple first dimming units are arranged with projection intervals on the first reference surface, and at least two of the multiple first dimming units are arranged with projection intervals on the second reference surface, wherein the first reference surface is perpendicular to the first direction, the second reference surface is perpendicular to the second direction, the first direction is the arrangement direction of the light source and the light guide plate, and the first direction intersects with the second direction.

[0010] In some optional embodiments, the distribution density of the first dimming units gradually increases in a direction away from the light incident surface.

[0011] In some optional embodiments, the maximum height of the plurality of first dimming units in the thickness direction of the light guide plate gradually increases in a direction away from the light incident surface.

[0012] In some optional embodiments, the first dimming unit has at least one adjustment surface facing the light incident surface, and the distance from the adjustment surface to the light emitting surface gradually decreases in a direction away from the corresponding light incident surface.

[0013] In some optional embodiments, the angle between the adjustment surface and the plane where the light guide plate is located is greater than or equal to 10° and less than or equal to 45°.

[0014] In some optional embodiments, a length of the adjustment surface in the first direction is greater than or equal to 10 micrometers and less than or equal to 45 micrometers.

[0015] In some optional embodiments, when the first surface is the dimming surface, the dimming unit on the first surface is a second dimming unit, the second dimming unit extends along the second direction, and a plurality of the second dimming units are arranged at intervals along the first direction, wherein the first direction is the arrangement direction of the light source and the light guide plate, and the first direction intersects with the second direction.

[0016] In some optional embodiments, a longitudinal section of the second dimming unit perpendicular to the second direction is a triangular structure, and an angle of the triangular structure away from the second surface is greater than or equal to 45° and less than or equal to 145°.

[0017] In some optional embodiments, a maximum length of the second dimming unit in the first direction is greater than or equal to 20 micrometers and less than or equal to 180 micrometers.

[0018] In some optional embodiments, the second surface has a plurality of diffusion units, at least two of the plurality of diffusion units are arranged with an orthographic projection interval on the first reference plane, and at least two of the plurality of diffusion units are arranged with an orthographic projection interval on the second reference plane, wherein the first reference plane is perpendicular to the first direction, and the second reference plane is perpendicular to the second direction.

[0019] In some optional embodiments, a length of the diffusion unit in the first direction is greater than or equal to 10 micrometers and less than or equal to 100 micrometers.

[0020] In some optional embodiments, the diffusion unit includes a curved surface convex in a direction away from the first surface.

[0021] In some optional embodiments, a plurality of light emitting units are provided on the light emitting surface, the light emitting units extend along the second direction, and the plurality of light emitting units are arranged at intervals along the first direction.

[0022] In some optional embodiments, the maximum height of the light output unit is less than 1 micron.

[0023] In some optional embodiments, the length of the light emitting unit in the first direction is greater than or equal to 3 micrometers and less than or equal to 25 micrometers.

[0024] In some optional embodiments, the backlight module further includes a prism assembly, and the prism assembly includes:

[0025] a first prism sheet, the first prism sheet being located on a side of the diffuser away from the light guide plate, the first prism sheet having a plurality of first prisms on a surface of the side away from the diffuser, the first prisms extending along the first direction, and the plurality of first prisms being arranged at intervals along the second direction;

[0026] A second prism sheet, wherein the second prism sheet is located on a side of the first prism sheet away from the diffuser sheet, and a surface of the second prism sheet on a side away from the first prism sheet has a plurality of second prisms, the second prisms extend along the second direction, and the plurality of second prisms are arranged at intervals along the first direction.

[0027] According to another aspect of the present invention, a display device is provided, comprising the above-mentioned backlight module. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the present invention but do not constitute a limitation of the present invention. In the accompanying drawings:

[0029] Figure 1 A top view of a backlight module according to an optional embodiment of the present invention is shown;

[0030] Figure 2 Shown Figure 1 Middle AA view;

[0031] Figure 3 Shown Figure 2 Diagram of the light path in the middle diffuser;

[0032] Figure 4 Shown Figure 2 Diagram of the light path in the middle light guide plate;

[0033] Figure 5 Shown Figure 1 Schematic diagram of the structure of the middle light guide plate;

[0034] Figure 6 Shown Figure 1 Another angle view of the first prism;

[0035] Figure 7 It shows the brightness distribution diagram of the center position of the backlight module at different viewing angles in another optional embodiment of the present utility model;

[0036] Figure 8 FIG2 shows a flow chart for manufacturing a light guide plate in another optional embodiment of the present invention;

[0037] Figure 9 A schematic structural diagram of a backlight module in an example is shown;

[0038] Figure 10 Shown Figure 9 Diagram of the light path in the middle diffuser;

[0039] Figure 11 Shown Figure 9 Brightness distribution at different viewing angles at the center of the backlight module.

[0040] 10. Light source; 20. Light guide plate; 21. Light incident surface; 22. Light emitting surface; 221. Light emitting unit; 23. Bottom surface; 30. Diffuser; 31. First surface; 32. Second surface; 321. Diffuser unit; 40. First dimming surface; 41. First dimming unit; 411. Adjustment surface; 50. Second dimming surface; 51. Second dimming unit; 60. Prism assembly; 61. First prism sheet; 611. First prism; 62. Second prism sheet; 621. Second prism; 70. Reflector; 80. Primary template; 90. Secondary template; 100. Lower mold core; 110. Upper mold core. DETAILED DESCRIPTION

[0041] The following is a detailed description of the specific embodiments of the present invention in conjunction with the accompanying drawings. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention and are not intended to limit the present invention.

[0042] To make the purpose, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the described embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0043] Unless otherwise defined, the technical terms or scientific terms used in the embodiments of the present invention should have the usual meanings understood by people with ordinary skills in the field to which the present invention belongs. The "first", "second" and similar words used in the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. Similarly, words such as "include" or "comprise" mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. Words such as "connect" or "connected" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the object being described changes, the relative positional relationship may also change accordingly.

[0044] As used herein, "parallel" and "perpendicular" include the conditions described and conditions similar to the conditions described, and the range of the similar conditions is within an acceptable deviation range, wherein the acceptable deviation range is determined by a person of ordinary skill in the art taking into account the measurement in question and the errors associated with the measurement of the specific quantity (i.e., the limitations of the measurement system). For example, "parallel" includes absolute parallelism and approximate parallelism, wherein the acceptable deviation range for approximate parallelism can be, for example, a deviation within 5°; "perpendicular" includes absolute perpendicularity and approximate perpendicularity, wherein the acceptable deviation range for approximate perpendicularity can also be, for example, a deviation within 5°.

[0045] It will be understood that when a layer or element is referred to as being on another layer or substrate, it can be directly on the other layer or substrate, or intervening layers may be present therebetween.

[0046] Exemplary embodiments are described herein with reference to cross-sectional and / or plan views that are idealized exemplary drawings. In the drawings, the thicknesses of layers and regions are exaggerated for clarity. Therefore, variations in shape relative to the drawings due to, for example, manufacturing techniques and / or tolerances are contemplated. Therefore, the exemplary embodiments should not be construed as limited to the shapes of the regions shown herein, but rather include deviations in shape due to, for example, manufacturing. Therefore, the regions shown in the drawings are schematic in nature, and their shapes are not intended to illustrate the actual shape of regions of the device and are not intended to limit the scope of the exemplary embodiments.

[0047] Figure 1 FIG2 shows a schematic top view of a backlight module in one embodiment of the present invention. Figure 2 Shown Figure 1 Middle AA view, from Figure 1 and Figure 2As can be seen in the figure, the backlight module includes at least one light source 10, a light guide plate 20 and a diffuser 30. The light guide plate 20 includes a light incident surface 21, a light emitting surface 22 and a bottom surface 23 arranged opposite to the light emitting surface 22. The light incident surface 21 is located on the side of the light guide plate 20 facing the light source 10. The light incident surface 21 is connected to the light emitting surface 22 and the bottom surface 23, so that the light emitted by the light source 10 enters the light guide plate 20 from one side, forming a side-entry backlight module. After the light enters the light guide plate 20, part of the light is reflected multiple times between the light emitting surface 22 and the bottom surface 23 and then emitted through the light emitting surface 22, while the other part of the light is directly reflected by the bottom surface 23 to the light emitting surface 22 and emitted. The light emitted from the light guide plate 20 enters the diffuser 30.

[0048] When there are multiple light sources 10, the light guide plate 20 has multiple light incident surfaces 21, and each light source 10 corresponds to a light incident surface 21. Figure 2 For example, when there are two light sources 10, the two light sources 10 are located on opposite sides of the light guide plate 20, and there are two light incident surfaces 21, which are located on opposite sides of the light emitting surface 22 and the bottom surface 23, so that the light emitted by each light source 10 enters the interior of the light guide plate 20 through the corresponding light incident surface 21.

[0049] exist Figure 2 In the specific embodiment shown, the diffuser 30 is located on the light-emitting side of the light guide plate 20. The diffuser 30 includes a first surface 31 and a second surface 32 arranged opposite to each other, with the first surface 31 being closer to the light guide plate 20 than the second surface 32. The bottom surface 23 and the first surface 31 serve as dimming surfaces, and the dimming surface has a plurality of dimming units. The dimming units are configured to adjust the light so that the light-emitting angle of the diffuser 30 is within a preset range. By providing a plurality of dimming units on the dimming surface, the dimming units adjust the light so that the light emitted from the diffuser 30 is concentrated within a preset angle range to increase the brightness of the light. This arrangement increases the brightness of the light emitted by the backlight module under the same current, thereby reducing the power consumption of the backlight module.

[0050] It should be noted that the function of the diffuser 30 is not to diffuse the light in a large angle direction, but to even out the light and adjust the light so that the light is evenly distributed within a preset angle range.

[0051] In some optional embodiments, only the bottom surface 23 serves as a dimming surface, while the diffuser 30 does not have a dimming surface. The dimming surface can adjust the light so that the light emitted by the diffuser 30 is concentrated within a preset angle range, thereby achieving the effect of increasing the brightness of the light. For example, when the bottom surface 23 serves as an adjustment surface, the light emitted by the light guide plate 20 is concentrated within the preset angle range, while the diffuser 30 can only perform a uniform light distribution function without any adjustment function, ensuring that the light emitted by the diffuser 30 remains concentrated within the preset angle range.

[0052] In other optional embodiments, only the first surface 31 is a dimming surface, and the light guide plate 20 does not have a dimming surface, which can adjust the light so that the light emitted by the diffuser 30 is concentrated within a preset angle range, thereby achieving the effect of improving the brightness of the light.

[0053] exist Figure 2 In the specific embodiment shown, the bottom surface 23 and the first surface 31 are both dimming surfaces. When the light is irradiated to the dimming unit on the bottom surface 23, the dimming unit on the bottom surface 23 performs preliminary adjustment on the light to reduce the light emission angle. After the light is transmitted from the light guide plate 20 to the diffuser 30, the dimming unit on the diffuser 30 adjusts the light again. After the light is adjusted twice by the light guide plate 20 and the diffuser 30, the light emitted from the diffuser 30 is concentrated within a preset angle range, which is beneficial to improving the light output brightness of the backlight module.

[0054] It should be noted that although the bottom surface 23 and the first surface 31 can be a dimming surface, the specific structures of the dimming units of the dimming surfaces in different structures are different. For example, when the bottom surface 23 is a dimming surface, the dimming units are a two-dimensional structure, while when the first surface 31 is a dimming surface, the dimming units are a one-dimensional structure. A two-dimensional structure means that the dimming units are arranged in two directions, or have periodicity in two dimensions, while a one-dimensional structure means that the dimming units are arranged in one direction, or have periodicity in one dimension.

[0055] In some alternative embodiments, see Figure 2 and Figure 4 When the bottom surface 23 is a dimming surface, the bottom surface 23 is a first dimming surface 40. The first dimming surface 40 has a plurality of first dimming cells 41. The projections of at least two of the plurality of first dimming cells 41 on the first reference surface are spaced apart. The projections of at least two of the plurality of first dimming cells 41 on the second reference surface are spaced apart. The first reference surface is perpendicular to the first direction, the second reference surface is perpendicular to the second direction, the first direction is the arrangement direction of the light source 10 and the light guide plate 20, and the first direction intersects the second direction. In other words, the plurality of first dimming cells 41 are divided into a plurality of rows of first dimming groups, the plurality of rows of first dimming groups are spaced apart along the first direction, and each first dimming group contains at least one first dimming cell. If each first dimming group contains only one first dimming cell, the at least two first dimming cells are not aligned in the first direction, so that the at least two first dimming cells are arranged in the second direction. If at least one first dimming group includes a plurality of first dimming units, the plurality of first dimming units in the first dimming group are spaced apart along the second direction.

[0056] It should be noted that the first direction is direction X, and the second direction is direction Y.

[0057] In some optional embodiments, the distribution density of the first dimming units 41 gradually increases in a direction away from the light incident surface 21. In the light guide plate 20, the light intensity in the area close to the light incident surface 21 is greater than the light intensity in the area away from the light incident surface 21. The distribution density of the first dimming units 41 in the area close to the light incident surface 21 is low, so as to ensure the intensity of the light transmitted to the area away from the light incident surface 21. This is conducive to the uniform distribution of the light intensity of the light emitted from the light exiting surface 22, and reduces the situation where the light intensity in some areas of the light exiting surface 22 is too strong and the light intensity in other areas is too weak.

[0058] It should be noted that when there is only one light source 10, only one side of the light guide plate 20 has a light incident surface 21. In this case, the distribution density of the first dimming units 41 within the entire light guide plate 20 gradually increases in the direction away from the light incident surface 21. If there are two light sources 10, and the two light sources 10 are located on opposite sides of the light guide plate 20, the distribution density of the first dimming units 41 gradually increases from the two light incident surfaces 21 toward the center of the light guide plate 20.

[0059] In some optional embodiments, the maximum height of the plurality of first dimming units 41 in the thickness direction of the light guide plate 20 gradually increases in the direction away from the light incident surface 21. The light intensity in the area near the light incident surface 21 within the light guide plate 20 is greater than the light intensity in the area away from the light incident surface 21. In the area near the light incident surface 21, the maximum height of the first dimming units 41 in a plane perpendicular to the light guide plate 20 is smaller, which can reduce the intensity of light reflected to the light emitting surface 22, thereby ensuring the light intensity guided to the area away from the light incident surface 21, and facilitating uniform distribution of the light intensity emitted from the light emitting surface 22.

[0060] It should be noted that when there is only one light source 10, only one side of the light guide plate 20 has the light incident surface 21. In this case, the maximum height of the multiple first dimming units 41 in the entire light guide plate 20 in the thickness direction of the light guide plate 20 gradually decreases and increases in the direction away from the light incident surface 21. If there are two light sources 10, and the two light sources 10 are located on opposite sides of the light guide plate 20, the maximum height of the first dimming units 41 in the thickness direction of the light guide plate 20 gradually increases from the two light incident surfaces 21 toward the center of the light guide plate 20.

[0061] In some alternative embodiments, see Figure 2 The first dimming unit 41 has at least one adjustment surface 411 facing the light incident surface 21. The distance between the adjustment surface 411 and the light emitting surface 22 gradually decreases as it moves away from the corresponding light incident surface 21. The adjustment surface 411 is an inclined plane that facilitates reflecting light onto the light emitting surface 22 so that the light is emitted from the light emitting surface 22.

[0062] It should be noted that when the light guide plate 20 has one light incident surface 21, the first dimming unit 41 has an adjustment surface 411. If the light guide plate 20 has two light incident surfaces 21, the two light incident surfaces 21 are located on opposite sides of the light guide plate 20. For example, the two light incident surfaces 21 are respectively the first light incident surface and the second light incident surface. The first dimming unit 41 may have only one adjustment surface 411, and the adjustment surfaces 411 on the multiple first dimming units 41 close to the first light incident surface face the first light incident surface, and the adjustment surfaces 411 on the multiple first dimming units 41 close to the second light incident surface face the second light incident surface. Alternatively, each first dimming unit 41 may have two adjustment surfaces 411, and the two adjustment surfaces 411 are arranged facing the two light incident surfaces 21. There is no specific restriction on the correspondence between the adjustment surface 411 and the light incident surface 21 on the first dimming unit 41. It is only necessary to ensure that the first dimming unit 41 has at least one adjustment surface 411 facing the light incident surface 21.

[0063] In some optional embodiments, the maximum heights of the adjustment surfaces 411 on the multiple first dimming units 41 gradually increase in a direction away from the light incident surface 21, which helps ensure uniform light output from the light output surface 22. When a first dimming unit 41 has multiple adjustment surfaces 411, the maximum heights of the multiple adjustment surfaces 411 are the same. It is sufficient to ensure that the maximum heights of the first dimming unit 41 gradually increase in a direction away from the light incident surface 21.

[0064] Optionally, the maximum height of the adjustment surface 411 is the maximum height of the first dimming unit 41 .

[0065] In some optional embodiments, the first dimming unit 41 is in the shape of a quadrangular pyramid.

[0066] In some optional embodiments, the angle between the adjustment surface 411 and the plane where the light guide plate 20 is located is greater than or equal to 10° and less than or equal to 45°. If the angle between the adjustment surface 411 and the plane where the light guide plate 20 is located is less than 10°, it is not conducive to the light being incident on the adjustment surface 411. If the angle between the adjustment surface 411 and the plane where the light guide plate 20 is located is greater than 45°, it is not conducive to the adjustment surface 411 reflecting the light onto the light exit surface 22. Limiting the angle between the adjustment surface 411 and the plane where the light guide plate 20 is located to a range of 10° to 45° is conducive to the adjustment surface 411 receiving light and reflecting the light onto the light exit surface 22.

[0067] In some optional embodiments, the first dimming unit 41 has an adjustment surface 411, and the technical solution in which the maximum height of the adjustment surfaces 411 on the multiple first dimming units 41 gradually increases in the direction away from the light incident surface 21 can have various forms. For example, the angles between the multiple adjustment surfaces 411 and the plane where the light guide plate 20 is located are the same, and the widths of the multiple adjustment surfaces 411 in the first direction gradually increase in the direction away from the light incident surface 21. For another example, the widths of the multiple adjustment surfaces 411 in the first direction are the same, and the angles between the multiple adjustment surfaces 411 and the plane where the light guide plate 20 is located gradually increase. It is also possible that the widths of the multiple adjustment surfaces 411 in the first direction and the angles between the multiple adjustment surfaces 411 and the plane where the light guide plate 20 is located are different, and no specific limitation is made here.

[0068] In some optional embodiments, the length of the adjustment surface 411 in the first direction is greater than or equal to 10 microns and less than or equal to 45 microns. The length of the adjustment surface 411 in the first direction refers to the length of the orthographic projection of the adjustment surface 411 on the plane of the light guide plate 20 in the first direction. By limiting the length of the adjustment surface 411 in the first direction, it is helpful to control the maximum height of the adjustment surface 411 within a reasonable range, which helps to ensure that light is adjusted while it is transmitted horizontally within the light guide plate 20.

[0069] In some optional embodiments, when the first surface 31 is a dimming surface, the first surface 31 is a second dimming surface 50, and the second dimming surface 50 has a plurality of second dimming units 51. The second dimming units 51 extend along the second direction, and the plurality of second dimming units 51 are arranged at intervals along the first direction, wherein the first direction is the arrangement direction of the light source 10 and the light guide plate 20, and the first direction intersects the second direction. In other words, the second dimming units 51 are strip-shaped structures, and the strip structures are arranged along the same direction. By providing multiple second dimming units 51 on the first surface 31, it is beneficial to control the light output angle of the diffuser 30 within a preset angle range, thereby improving the light output intensity.

[0070] In some alternative embodiments, see Figure 2 The second dimming unit 51 protrudes in a direction away from the second surface 32, and the longitudinal cross-section of the second dimming unit 51 perpendicular to the second direction has a triangular structure. The angle of the triangular structure away from the second surface 32 is greater than or equal to 45° and less than or equal to 145°. Limiting the angle of the triangular structure away from the second surface 32 to a range of 45° to 145° facilitates the smooth entry of light into the diffuser 30, reduces reflection by the second dimming unit 51, and effectively reduces light energy loss.

[0071] In some optional embodiments, the maximum length of the second dimming cells 51 in the first direction is greater than or equal to 20 microns and less than or equal to 180 microns. Controlling the maximum length of the second dimming cells 51 in the first direction within a range of 20 microns to 180 microns helps ensure the distribution density of the second dimming cells 51, reduces the light output angle, and reduces the difficulty of manufacturing the diffuser 30.

[0072] In some optional embodiments, the second surface 32 comprises a plurality of diffusion units 321, wherein at least two of the plurality of diffusion units 321 are spaced apart in their orthographic projections on a first reference plane, and at least two of the plurality of diffusion units 321 are spaced apart in their orthographic projections on a second reference plane, wherein the first reference plane is perpendicular to the first direction, and the second reference plane is perpendicular to the second direction. In other words, the diffusion units 321 have a two-dimensional structure. Alternatively, the plurality of diffusion units 321 are divided into multiple rows of diffusion groups, each of which is spaced apart along the first direction, each containing at least one diffusion unit 321. If each diffusion group contains only one diffusion unit 321, the at least two diffusion units 321 are not aligned in the first direction, such that the at least two diffusion units 321 are arranged in the second direction. Alternatively, if at least one diffusion group contains multiple diffusion units 321, the multiple diffusion units 321 within the diffusion group are spaced apart along the second direction.

[0073] By providing multiple diffusion units 321 on the second surface 32, it is beneficial to evenly distribute the light, avoiding the situation where the light intensity in some areas is strong and the light intensity in other areas is weak, so that the light emitted by the diffusion sheet 30 is evenly distributed within a preset angle.

[0074] In some optional embodiments, the length of the diffusion unit 321 in the first direction is greater than or equal to 10 microns and less than or equal to 100 microns. This configuration can ensure the light uniformity effect of the diffusion unit 321 while avoiding increasing the difficulty of manufacturing the diffusion sheet 30.

[0075] exist Figure 2 and Figure 3 In the embodiment shown, the diffusion unit 321 includes a curved surface that protrudes away from the first surface 31. In other words, the diffusion unit 321 is a protrusion disposed on the second surface 32, and is a semicircular or elliptical protrusion.

[0076] In some alternative embodiments, see Figure 5The light emitting surface 22 is provided with a plurality of light emitting units 221. The light emitting units 221 are configured to couple light from the light guide plate 20. The light emitting units 221 extend along the second direction and are spaced apart along the first direction. The provision of multiple light emitting units 221 on the light emitting surface 22 not only helps to evenly distribute the light, but also helps to evenly distribute the light. Furthermore, the extension direction of the light emitting units 221 is parallel to the extension direction of the second dimming units 51. The light emitting units 221 and the second dimming units 51 cooperate to further reduce the light output angle of the diffuser 30.

[0077] In some optional embodiments, the maximum height of the light emitting unit 221 is less than 1 micron. This arrangement ensures the uniform light effect while ensuring the thickness of the light guide plate 20, which is conducive to making the backlight module lighter and thinner.

[0078] In some optional embodiments, the length of the light emitting unit 221 in the first direction is greater than or equal to 3 micrometers and less than or equal to 25 micrometers. This configuration can ensure the light emitting unit 221 has a uniform light effect on the light and reduce the waste of light energy.

[0079] In some alternative embodiments, see Figure 2 and Figure 6 The backlight module also includes a prism assembly 60, which includes a first prism sheet 61 and a second prism sheet 62. The first prism sheet 61 is located on the side of the diffuser 30 away from the light guide plate 20, and the surface of the first prism sheet 61 away from the diffuser 30 has a plurality of first prisms 611, the first prisms 611 extend along the first direction, and the plurality of first prisms 611 are arranged at intervals along the second direction; the second prism sheet 62 is located on the side of the first prism sheet 61 away from the diffuser 30, and the surface of the second prism sheet 62 away from the first prism sheet 61 has a plurality of second prisms 621, the second prisms 621 extend along the second direction, and the plurality of second prisms 621 are arranged at intervals along the first direction. By setting up the prism assembly 60, the light can be further concentrated and the light output angle of the backlight module can be reduced. In addition, the extension direction of the first prism 611 is crossed with the extension direction of the second dimming unit 51, and the extension direction of the second prism 621 is parallel to the extension direction of the second dimming unit 51. This can reduce the light output angle of the prism assembly 60 and further reduce the light output angle of the backlight module, which is conducive to more concentrated light intensity of the backlight module.

[0080] In some alternative embodiments, see Figure 2 The backlight module further includes a reflective plate 70 , which is located on a side of the light guide plate 20 away from the diffuser 30 to reflect the light emitted from the light guide plate 20 through the bottom surface 23 into the light guide plate 20 to reduce light energy loss.

[0081] The structural design on the first surface 31 and the second surface 32 of the diffuser 30 of the present invention is that the first surface 31 is a dimming surface, and the second surface 32 has multiple diffusion units 321. These can adjust the light output from the light guide plate 20 to a preset angle range. The light within this range can be further adjusted to near 0° through the first prism sheet 61 and the second prism sheet 62, thereby making the light output angle of the backlight module greater than or equal to -5° and less than or equal to 5°, so that the light output from the backlight module is more concentrated within the range of -5° to 5°, achieving the effect of improving brightness. For example, the light output angle of the backlight module is greater than or equal to -2° and less than or equal to 2°.

[0082] Figure 9 The light uniformity of the backlight module shown in the figure is 81.9%, and the half-peak width of the viewing angle is 46.7°. Figure 10 The relative center brightness of the backlight module shown in is 100%, see Figure 11 , then in an optional embodiment of the present invention, for example, when the light output angle of the diffuser 30 is within the range of 50° to 60°, the light output uniformity of the backlight module is 86.6%, the half-peak width of the viewing angle is 49.1°, and the relative center brightness of the backlight module is 144%. Figure 7 . It can be seen from this that the backlight module in this application is relatively Figure 9 The center brightness of the backlight module in the example is increased by 44%, the uniformity is improved by 5.7%, and the viewing angle level is basically the same.

[0083] In addition, from Figure 10 for Figure 9 Diagram of the light path in the middle diffuser. Figure 3 Shown Figure 2 The light path in the diffuser, from Figure 10 and Figure 3 It can be seen from the comparison that Figure 3 The light output angle of the middle diffuser 30 becomes smaller and is concentrated within a preset angle range, for example, within a range of 40° to 75°, for example, within a range of 45° to 70°, for example, within a range of 50° to 60°.

[0084] It should be noted that when the refractive index of the first prism base layer in the first prism sheet 61 and the second prism base layer in the second prism sheet 62 is in the range of 1.45 to 1.65, and the refractive index of the first prism 611 and the second prism 621 is in the range of 1.57 to 1.77, the peak brightness at the center of the backlight module increases first and then decreases with the light output angle of the diffuser 30. The peak brightness reaches its maximum at 50° to 60°, and reaches half of the maximum peak brightness at 40° and 75°. At 80° to 85°, the peak brightness at the center of the backlight module drops sharply, decreasing to 10% of the maximum peak brightness. Figure 9 The light emission angles of the diffuser 30 of the backlight module shown are mostly concentrated in the range of 80° to 85°. The light emission angles of the diffuser 30 of the backlight module shown in the present invention are in the range of 40° and 75°, which effectively improves the brightness of the center position.

[0085] For example, the refractive index of the first prism base layer and the second prism base layer is 1.55. For another example, the refractive index of the first prism 611 and the second prism 621 is 1.67.

[0086] Optionally, the light emission angle of the diffuser 30 is within a range of 40° and 75°.

[0087] When the angle of the diffuser 30 is in the range of 40° to 85°, the central viewing angle of the light emitted by the backlight module is less than 20°. It can be seen that by limiting the light output angle of the diffuser 30 to the range of 40° and 75°, the brightness of the center position can be improved while ensuring that the central viewing angle of the backlight module remains unchanged.

[0088] It should be noted that the angle of the light is the angle between the light and an axis perpendicular to the plane where the light guide plate 20 is located.

[0089] The light guide plate 20 of the present invention can be formed by various processes such as injection molding and hot pressing, wherein the mold core can be formed by various processes such as laser, photolithography, and point collision. Figure 8 This is an example of the process flow for photolithography molds and injection molding of light guide plates. The main steps include photolithography, coating, electroplating, transfer, lamination, and injection molding. Specifically, a primary template 80 is formed by photolithography. A corrosion-resistant material is applied to primary template 80 to form a secondary template 90. Secondary template 90 is then electroplated to form a metal film. Secondary template 90 and the metal film are separated, and a lower mold 100 is formed on the back of the metal film. Lower mold 100 and upper mold 110 are then combined to form an injection mold. Light guide plate 20 is then formed within the injection mold.

[0090] In some optional embodiments, the diffuser 30 is a single-layer optical film layer, which can be formed by embossing.

[0091] According to another aspect of the present invention, a display device is provided, comprising the aforementioned backlight module. The display device having the aforementioned backlight module has the advantages of high light efficiency and low power consumption. For example, the display device is a head-mounted display device.

[0092] It is understood that the above embodiments are merely exemplary embodiments for illustrating the principles of the present invention, and the present invention is not limited thereto. Those skilled in the art may make various modifications and improvements without departing from the spirit and substance of the present invention, and such modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

1. A backlight module, characterized in that: include: at least one light source; a light guide plate, the light guide plate comprising a light incident surface, a light emitting surface, and a bottom surface arranged opposite to the light emitting surface, the opposite ends of the light incident surface being connected to the light emitting surface and the bottom surface, respectively, and the light incident surface being located on a side of the light guide plate facing the light source; a diffuser, the diffuser being located on the light-emitting surface side of the light guide plate, the diffuser comprising a first surface and a second surface oppositely disposed, the first surface being closer to the light guide plate than the second surface; The bottom surface and / or the first surface is a dimming surface having a plurality of dimming units, and the dimming units are configured to adjust the light so that the light output angle of the diffuser is within a preset range.

2. The backlight module according to claim 1, wherein: When the bottom surface is the dimming surface, the dimming unit on the bottom surface is a first dimming unit, and at least two of the multiple first dimming units are arranged with projections on the first reference surface at intervals, and at least two of the multiple first dimming units are arranged with projections on the second reference surface at intervals, wherein the first reference surface is perpendicular to a first direction, the second reference surface is perpendicular to a second direction, the first direction is the arrangement direction of the light source and the light guide plate, and the first direction intersects with the second direction.

3. The backlight module according to claim 2, wherein: The distribution density of the first dimming units gradually increases in a direction away from the light incident surface.

4. The backlight module according to claim 2, wherein: The maximum heights of the plurality of first dimming units in the thickness direction of the light guide plate gradually increase in a direction away from the light incident surface.

5. The backlight module according to claim 2, wherein: The first dimming unit has at least one adjustment surface facing the light incident surface, and the distance between the adjustment surface and the light emitting surface gradually decreases in a direction away from the corresponding light incident surface.

6. The backlight module according to claim 5, wherein: An angle between the adjustment surface and the plane where the light guide plate is located is greater than or equal to 10° and less than or equal to 45°.

7. The backlight module according to claim 5, wherein: A length of the regulation surface in the first direction is greater than or equal to 10 micrometers and less than or equal to 45 micrometers.

8. The backlight module according to any one of claims 1 to 7, characterized in that: When the first surface is the dimming surface, the dimming unit on the first surface is a second dimming unit, the second dimming unit extends along the second direction, and a plurality of the second dimming units are arranged at intervals along the first direction, wherein the first direction is the arrangement direction of the light source and the light guide plate, and the first direction intersects with the second direction.

9. The backlight module according to claim 8, wherein: The second dimming unit has a triangular structure in a longitudinal section perpendicular to the second direction, and an angle of the triangular structure away from the second surface is greater than or equal to 45° and less than or equal to 145°.

10. The backlight module according to claim 8, wherein: A maximum length of the second dimming unit in the first direction is greater than or equal to 20 micrometers and less than or equal to 180 micrometers.

11. The backlight module according to claim 8, wherein: The second surface has multiple diffusion units, at least two of the multiple diffusion units are arranged at intervals on the orthographic projections of the first reference plane, and at least two of the multiple diffusion units are arranged at intervals on the orthographic projections of the second reference plane, wherein the first reference plane is perpendicular to the first direction and the second reference plane is perpendicular to the second direction.

12. The backlight module according to claim 11, wherein: A length of the diffusion unit in the first direction is greater than or equal to 10 micrometers and less than or equal to 100 micrometers.

13. The backlight module according to claim 11, wherein: The diffusion unit includes a curved surface that bulges away from the first surface.

14. The backlight module according to claim 8, wherein: A plurality of light emitting units are provided on the light emitting surface, the light emitting units extend along the second direction, and the plurality of light emitting units are arranged at intervals along the first direction.

15. The backlight module according to claim 14, wherein: The maximum height of the light emitting unit is less than 1 micron.

16. The backlight module according to claim 14, wherein: The length of the light emitting unit in the first direction is greater than or equal to 3 micrometers and less than or equal to 25 micrometers.

17. The backlight module according to any one of claims 1 to 16, characterized in that: The backlight module further includes a prism assembly, and the prism assembly includes: a first prism sheet, the first prism sheet being located on a side of the diffuser away from the light guide plate, the first prism sheet having a plurality of first prisms on a surface of the side away from the diffuser, the first prisms extending along a first direction, and the plurality of first prisms being arranged at intervals along a second direction; A second prism sheet, wherein the second prism sheet is located on a side of the first prism sheet away from the diffuser sheet, and a surface of the second prism sheet on a side away from the first prism sheet has a plurality of second prisms, the second prisms extend along the second direction, and the plurality of second prisms are arranged at intervals along the first direction.

18. A display device, characterized in that: The backlight module comprises the backlight module according to any one of claims 1 to 17.

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