Light diffusion piece, display equipment and vehicle

Abstract

The invention relates to a light diffusion piece, a display device and a vehicle, the light diffusion piece comprises a substrate layer, a micro lens array and at least one light transmission layer, the micro lens array is arranged on the substrate layer, the micro lens array comprises a plurality of micro lens structures arranged in an array mode, and the at least one light transmission layer is arranged on the back light emitting side of the micro lens array in a stacked mode. The light-transmitting layer comprises a plurality of sub-light-transmitting parts, the number of the sub-light-transmitting parts is smaller than that of the micro-lens structures, and the sub-light-transmitting parts are arranged on the micro-lens structures in a one-to-one correspondence mode. The diffusion piece is beneficial to improving the uniformity of the brightness of each part of the image formed by the light beams, improving the definition of each part of the formed image and improving the display effect.

Description

Technical Field

[0001] The present application relates to the technical field of display devices, and in particular to a light diffuser, a display device and a vehicle. Background Art

[0002] HUD (Head-Up Display) technology plays a vital role in vehicle safety systems. It significantly improves driving safety and convenience by projecting key driving information such as speed, navigation guidance, traffic sign recognition, and warnings from the vehicle's advanced driver assistance system (ADAS) directly in front of the driver's line of sight.

[0003] HUD imaging uniformity is one of the important indicators for evaluating the performance of the HUD system. Imaging uniformity involves whether the brightness, color and image distribution of the HUD display are consistent in the field of view, which directly affects the driver's visual experience and safety.

[0004] However, the HUD imaging uniformity in related technologies is low, and some areas of the image are not clear. Summary of the invention

[0005] Based on this, a light diffuser, a display device and a vehicle are provided, so that the light diffuser can be used to improve the imaging uniformity of the display device and improve the clarity of the image formed in all places.

[0006] According to one aspect of the present application, a light diffuser is provided, the light diffuser comprising:

[0007] basal layer;

[0008] a microlens array, disposed on the base layer, the microlens array comprising a plurality of microlens structures arranged in an array; and

[0009] At least one light-transmitting layer is stacked on the light-emitting side of the microlens array, the light-transmitting layer includes a plurality of sub-light-transmitting portions, the number of which is less than the number of the microlens structures, and the sub-light-transmitting portions are arranged one-to-one on part of the microlens structures.

[0010] In one embodiment, the microlens array includes a plurality of first microlenses and a plurality of second microlenses, at least one of the second microlenses is disposed between two adjacent first microlenses, at least one layer of the light-transmitting layer includes a plurality of first sub-light-transmitting portions arranged in an array, and the plurality of first sub-light-transmitting portions are disposed on the first microlenses in a one-to-one correspondence.

[0011] In one embodiment, at least one of the light-transmitting layers further includes a plurality of second sub-light-transmitting portions arranged in an array, and the plurality of second sub-light-transmitting portions are disposed on the first microlenses or the second microlenses in a one-to-one correspondence.

[0012] In one embodiment, at least one of the light-transmitting layers further includes a plurality of second sub-light-transmitting portions arranged in an array, and the plurality of second sub-light-transmitting portions are disposed on the first microlens and the second microlens adjacent to the first microlens.

[0013] In one embodiment, along the direction from the base layer to the microlens array, the first sub-light-transmissive portion and the second sub-light-transmissive portion may be arranged in the same layer or in a stacked manner.

[0014] In one embodiment, the number m of the second microlenses between two adjacent first microlenses satisfies: m≤10.

[0015] In one of the embodiments, the refractive index n1 of the sub-light-transmitting portion and the refractive index n2 of the microlens structure satisfy: 1.4≤n1≤2.8, 1.4≤n2≤2.8, and n1-n2≥0.1.

[0016] In one embodiment, the total number of layers a of at least one light-transmitting layer satisfies: 1≤a≤5, and along the direction from the base layer to the microlens array, the thickness h of the sub-light-transmitting portion satisfies: h≤2 um.

[0017] According to another aspect of the present application, a display device is provided, comprising a light emitting element and the light diffuser described in any one of the above embodiments, wherein the light diffuser is arranged on the light emitting side of the light emitting element.

[0018] According to yet another aspect of the present application, a vehicle is provided, comprising the above-mentioned display device.

[0019] The above-mentioned light diffuser can preliminarily modulate the light emitted by the light-emitting element of the display device through the microlens array. At the same time, a light-transmitting layer including a plurality of sub-light-transmitting portions is arranged on the light-emitting side of the microlens array. The sub-light-transmitting portions are arranged on the corresponding microlens structures to change the degree of bending of different light rays in the light beam after passing through different microlens structures and the corresponding sub-light-transmitting portions, thereby adjusting the light distribution in the light beam. That is, the present application can use the microlens array combined with the design of the light-transmitting layer to adjust the deflection effect of each light ray in the light beam, modulate the light beam, and help improve the uniformity of brightness at various locations of the image formed by the light beam, help improve the clarity of various locations of the formed image, and help improve the display effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] FIG. 1 shows a schematic structural diagram of a display device according to an embodiment of the present application.

[0021] FIG. 2 shows a schematic structural diagram of a light diffuser according to a first embodiment of the present application.

[0022] FIG. 3 a shows the propagation path of a light beam after passing through a microlens array with a large curvature radius in the prior art.

[0023] FIG. 3 b shows the propagation path of the light beam after passing through the light diffuser with a microlens structure having a large curvature radius of the present application.

[0024] FIG. 3 c shows a light intensity distribution diagram in the embodiment shown in FIG. 3 a .

[0025] FIG. 3 d shows a light intensity distribution diagram in the embodiment shown in FIG. 3 a .

[0026] FIG. 3 e shows a comparison of the propagation paths of light rays when there is and does not have a light-transmitting layer in the embodiment shown in FIG. 3 a .

[0027] FIG. 4 a shows the propagation path of a light beam after passing through a microlens array with a small curvature radius in the prior art.

[0028] FIG. 4 b shows the propagation path of the light beam after passing through the light diffuser having a microlens structure with a small curvature radius of the present application.

[0029] FIG. 4 c shows a light intensity distribution diagram in the embodiment shown in FIG. 4 a .

[0030] FIG. 4 d shows a light intensity distribution diagram in the embodiment shown in FIG. 4 b .

[0031] FIG. 5 a shows the light intensity distribution of an image formed by a light beam passing through a microlens array in the prior art.

[0032] FIG. 5 b shows the light intensity distribution of an image formed by a light beam passing through a light diffuser according to an embodiment of the present application.

[0033] FIG. 6 shows a schematic structural diagram of a light diffuser according to a second embodiment of the present application.

[0034] FIG. 7 shows a schematic structural diagram of a light diffuser according to a third embodiment of the present application.

[0035] FIG. 8 shows a schematic structural diagram of a light diffuser according to a fourth embodiment of the present application.

[0036] FIG. 9 shows a schematic structural diagram of a light diffuser according to a fifth embodiment of the present application.

[0037] FIG. 10 shows a flow chart of preparing a light diffuser according to an embodiment of the present application.

[0038] Description of Figure Numbers:

[0039] 10. Display device; 11. Light emitting element; 12. First reflecting element; 13. Second reflecting element; 14. Windshield;

[0040] 20. Light diffuser;

[0041] 100, base layer; 200, microlens array; 210, microlens structure; 300, light-transmitting layer; 310, first light-transmitting layer; 320, second light-transmitting layer; 330, sub-light-transmitting portion; 331, first sub-light-transmitting portion; 332, second sub-light-transmitting portion;

[0042] 400. Mould. DETAILED DESCRIPTION

[0043] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present application, so the present application is not limited by the specific embodiments disclosed below.

[0044] In the description of the present application, it should be understood that if the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. appear, the orientation or position relationship indicated by these terms is based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application.

[0045] In addition, if the terms "first" or "second" appear, these terms are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of this application, if the term "plurality" appears, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0046] In this application, unless otherwise clearly specified and limited, if the terms "installed", "connected", "connected", "fixed" and the like appear, these terms should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integrated connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0047] In the present application, unless otherwise clearly specified and limited, if there is a description that a first feature is "above" or "below" a second feature, etc., or similar descriptions appear, it may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature being "above", "above" and "above" the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. The first feature being "below", "below" and "below" the second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0048] It should be noted that if an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be a central element. If an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. If any, the terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used in this application are for illustrative purposes only and do not represent the only implementation method.

[0049] In the HUD (Head-Up Display) system, microlens array plays a vital role. Microlens array is a micro-optical element that can modulate the incident light for functions such as focusing, imaging, and beam transformation. In HUD, the application of microlens array can improve display quality, improve beam distribution, enhance image uniformity, and help achieve a more compact optical system design.

[0050] The HUD in the related art usually places a microlens array in the optical path of the picture generating unit (PGU) to modulate the light emitted by the picture generating unit (PGU). However, most of the diffusion elements such as the microlens array used in the HUD in the related art have the problem of uneven light distribution of the displayed image when the incident light is strong, thereby causing some areas of the displayed image to be unclear, making it impossible for the driver to judge the correct driving information.

[0051] Based on this, the present application provides a light diffuser, a display device and a vehicle, and the light diffuser can improve the brightness uniformity of the image displayed by the display device and improve the clarity of the displayed image.

[0052] Refer to FIG. 1 , which shows a schematic diagram of the structure of a display device 10 according to an embodiment of the present application. The display device 10 provided in the present application includes a light-emitting element 11, a light diffuser 20, a first reflective element 12, and a second reflective element 13. The display device 10 also has an imaging surface. In some embodiments, the imaging surface coincides with the windshield 14 of the vehicle. The light emitted by the light-emitting element 11 passes through the light diffuser 20, the first reflective element 12, and the second reflective element 13 in sequence and propagates to the imaging surface to form an image, so as to project the driving information in front of the driver's line of sight for the driver to watch. The light diffuser 20 is arranged on the light-emitting side of the light-emitting element 11 so as to be able to modulate the light emitted by the light-emitting element 11, so as to improve the light beam distribution, enhance the uniformity of the image display brightness, improve the clarity of the image at all locations, and thus improve the display quality.

[0053] In some embodiments, the light diffuser 20 can be disposed on the optical path of the light emitted by the light-emitting element 11, and is not limited to being disposed close to the light-emitting element 11 on the light-emitting side of the light-emitting element 11. That is, the light diffuser 20 can be disposed on the light-emitting side of the light-emitting element 11, or can be located on the optical path of the light emitted by the light-emitting element 11, and no excessive restrictions are made here.

[0054] Referring to FIG. 2 , FIG. 2 shows a schematic diagram of the structure of a light diffuser 20 according to a first embodiment of the present application. The light diffuser 20 provided by the present application includes a substrate layer 100 and a microlens array 200 disposed on the substrate layer 100. The microlens array 200 includes a plurality of microlens structures 210 arranged in an array. The microlens array 200 can be used to preliminarily modulate the light emitted by the light emitting element 11 and preliminarily adjust the light beam distribution, thereby improving the uniformity of the display brightness.

[0055] In some embodiments, the base layer 100 includes a light emitting surface of the light emitting element 11 , that is, the microlens structure 210 can be directly disposed on the light emitting surface of the light emitting element 11 to modulate the emitted light of the light emitting element 11 through the microlens structure 210 .

[0056] Continuing to refer to FIG. 2 , the light diffuser 20 provided by the present application further includes at least one light-transmitting layer 300, which is stacked on the light-emitting side of the microlens array 200 to further modulate the light emitted from the microlens array 200, further improve the brightness uniformity of the formed image, and improve the display quality. The light-transmitting layer 300 includes a plurality of sub-light-transmitting portions 330, the number of which is less than the number of the microlens structures 210, and the sub-light-transmitting portions 330 are arranged on part of the microlens structures 210 in a one-to-one correspondence.

[0057] It can be understood that the sub-light-transmitting portion 330 is arranged on the microlens structure 210, which is equivalent to forming a sub-diffusion portion through the sub-light-transmitting portion 330 and the corresponding microlens structure 210. Different from the deflection of light passing through a single microlens structure 210, the deflection of the light in the present application passing through the corresponding microlens structure 210 and the corresponding sub-light-transmitting portion 330 in sequence is obviously also related to the setting of the sub-light-transmitting portion 330. In this way, the adjustment of different degrees of deflection of light at various locations in the light beam can be achieved by setting sub-light-transmitting portions 330 with different parameters on the microlens structures 210 at different positions, changing the optical path of the light passing through different microlens structures 210, or changing the optical path difference between the light passing through different microlens structures 210. It can be understood that the optical path difference will affect the distribution of light on the imaging surface, thereby affecting the brightness uniformity of the image. In this way, by changing the optical path difference of light between different microlens structures 210 to change the light output path, the uniformity of the brightness of the displayed image can be improved, so that the image can be displayed more clearly.

[0058] By arranging a plurality of light-transmitting sub-portions on different microlens structures 210, the degree of deflection of light passing through different microlenses can be changed, and the optical path difference of light between different microlens structures 210 can be changed, so that the propagation path of light can be changed, so that a clear image can be displayed, which is beneficial to improving the display effect.

[0059] Please refer to FIG. 3e, which shows a comparison of the propagation paths of light rays when there is and does not have the light-transmitting layer 300 in the embodiment shown in FIG. 3a. FIG. 3e is a schematic diagram for better illustrating the effect and is for reference only. In FIG. 3e, the refractive index of the microlens structure 210 is 1.5, the refractive index of the light-transmitting layer 300 is 2.4, and the light-transmitting layer 300 is provided on the upper microlens structure 210 in FIG. 3e, while the light-transmitting layer 300 is not provided on the lower microlens structure 210. It can be seen that, compared with the microlens structure 210 without the light-transmitting layer 300 below, the focal length of the light rays of the microlens structure 210 with the light-transmitting layer 300 above is obviously larger, and the large-angle light rays at the edge are smoother, which is reflected in that the spacing of multiple light rays propagating to a distance is more uniform.

[0060] The light deflection is as follows: the light is deflected outward after entering the light-transmitting layer 300 with a larger refractive index from the microlens structure 210 with a smaller refractive index, and then the focal length after being focused from the light-transmitting layer 300 increases. However, when the light-transmitting layer 300 is not provided as shown below, the light is directly emitted after passing through the microlens structure 210, and the focal length is smaller. The uniformity of the light after being converged is obviously not as good as the uniformity of the light with the light-transmitting layer 300. In this way, the provision of the light-transmitting layer 300 of the present application can change the degree of deflection of the light, thereby changing the propagation path of the light, which is conducive to improving the uniformity of the brightness of each part of the image formed by the light beam.

[0061] The deflection degree of the light passing through the microlens array 200 and the sub-light-transmitting portion 330 on the microlens array 200 can also be adjusted by setting the thickness and material parameters of the sub-light-transmitting portion 330 at each location along the substrate 100 pointing to the microlens array 200. For example, when the convergence and deflection degree of a certain part of the light in the light beam needs to be increased, the thickness of the sub-light-transmitting portion on the microlens structure 210 through which the light passes can be adjusted accordingly to increase the degree of convergence and deflection of the light after passing through the corresponding microlens structure 210 and the sub-light-transmitting portion on the microlens structure 210. This allows the light deflection degree to be changed to a level that can display a clear image.

[0062] That is, the present application can achieve light beam modulation by setting the light-transmitting layer 300 on the microlens array 200. For example, by setting a plurality of sub-light-transmitting portions 330 respectively on different microlens structures 210, and by setting parameters such as the thickness of each sub-light-transmitting portion 330, the degree of deflection of light passing through the microlens array 200 and the light-transmitting layer 300 is adjusted, the optical path difference of light between different microlens structures 210 is adjusted, and the propagation path of light is changed, thereby facilitating the improvement of the uniformity of the displayed image, the improvement of the clarity of each part of the formed image, and the improvement of the display quality.

[0063] The light diffuser 20 of the present application can preliminarily modulate the light emitted by the light-emitting element 11 of the display device 10 through the microlens array 200. At the same time, a light-transmitting layer 300 including a plurality of sub-light-transmitting portions 330 is arranged on the light-emitting side of the microlens array 200. The sub-light-transmitting portions 330 are arranged on the corresponding microlens structures 210. By designing the thickness and material of the sub-light-transmitting portions 330 on the corresponding different microlens structures 210, the bending degree of different light rays in the light beam after passing through different microlens structures 210 and the corresponding sub-light-transmitting portions 330 can be changed, the optical path difference of the light rays between the different microlens structures 210 can be adjusted, the propagation path of the light rays can be changed, and then the light distribution in the light beam can be adjusted. That is, the present application can use the microlens array 200 in combination with the design of the light-transmitting layer 300 to adjust the deflection effect of each light ray in the light beam, modulate the light beam, and help improve the uniformity of the brightness of each part of the image formed by the light beam, help improve the clarity of each part of the formed image, and help improve the display effect.

[0064] In some embodiments, the refractive index n1 of the sub-light-transmitting portion 330 and the refractive index n2 of the microlens structure 210 satisfy: 1.4≤n1≤2.8, 1.4≤n2≤2.8, and n1-n2≥0.1. That is, the refractive index of the sub-light-transmitting portion 330 and the refractive index of the microlens structure 210 are both within the range of 1.4-2.8, and at the same time, the refractive index of the sub-light-transmitting portion 330 is greater than the refractive index of the microlens structure 210, and the difference between the refractive index of the sub-light-transmitting portion 330 and the refractive index of the microlens structure 210 is not less than 0.1. In this way, when light enters the sub-light-transmitting portion 330 with a larger refractive index from the microlens structure 210 with a smaller refractive index, it can be further deflected, which is beneficial to improve the deflection effect of the sub-light-transmitting portion on light.

[0065] Referring to FIG. 3a, FIG. 3b, FIG. 3c and FIG. 3d, FIG. 3a shows the propagation path of a light beam after passing through a microlens array 200 with a large curvature radius of the prior art. FIG. 3b shows the propagation path of a light beam after passing through a light diffuser 20 with a microlens structure 210 with a large curvature radius of the present application. FIG. 3c shows a light intensity distribution diagram in the embodiment shown in FIG. 3a. FIG. 3d shows a light intensity distribution diagram in the embodiment shown in FIG. 3b.

[0066] It can be seen, as shown in FIG3a, that after the light beam in the related art passes through the microlens array 200 with a large curvature radius, some of the light beams are obviously focused more severely, resulting in uneven light distribution, and the brightness of the image formed by the corresponding overall light beam is uneven. Referring to FIG3c, the horizontal axes in FIG3c, FIG3d, FIG4c and FIG4d all represent the light angle, and the vertical axes all represent the normalized light intensity. Referring to FIG3c, it can be seen that the top distribution of light intensity in the related art is more prominent, and the light intensity distribution is not stable. Obviously, the light intensity distribution at various locations of the corresponding image is quite different, which is reflected in the uneven light intensity at various locations in the image.

[0067] When the light beam passes through the light diffuser 20 of the present application, and the microlens structure 210 of the microlens array 200 in the light diffuser 20 of the present application has a large curvature radius, as shown in FIG3b, the propagation path of the light beam after passing through the light diffuser 20 is adjusted, and finally the light distribution of the entire light beam is relatively uniform, which is obviously conducive to improving the brightness uniformity of the displayed image. Referring to FIG3d, it can be seen that the top value of the light intensity in the present application tends to be stable and consistent, so that the corresponding light intensity distribution at various locations in the image also tends to be stable and consistent, which is reflected in the better uniformity of the light intensity at various locations in the image.

[0068] Referring to FIG. 4a, FIG. 4b, FIG. 4c and FIG. 4d, FIG. 4a shows the propagation path of a light beam after passing through a microlens array 200 with a small curvature radius of the prior art. FIG. 4b shows the propagation path of a light beam after passing through a light diffuser 20 with a microlens structure 210 with a small curvature radius of the present application. FIG. 4c shows a light intensity distribution diagram in the embodiment shown in FIG. 4a. FIG. 4d shows a light intensity distribution diagram in the embodiment shown in FIG. 4b.

[0069] As shown in FIG4a, after the light beam in the related art passes through the microlens array 200 with a small curvature radius, some of the light beams are obviously focused more severely, resulting in uneven light distribution and uneven brightness of the image formed by the corresponding overall light beam. Referring to FIG4c, it can be seen that the top distribution of light intensity in the related art is more prominent and unstable, with a large difference in values, and the corresponding light intensity distribution at various locations in the image is quite different, which is reflected in the uneven light intensity at various locations in the image.

[0070] When the light beam passes through the light diffuser 20 of the present application, and the microlens structure 210 of the microlens array 200 in the light diffuser 20 of the present application is a small curvature radius, as shown in FIG4b, the propagation path of the light beam after passing through the light diffuser 20 is adjusted, and finally the light distribution of the entire light beam is relatively uniform, which is obviously conducive to improving the brightness uniformity of the displayed image. Referring to FIG4d, it can be seen that the top value of the light intensity in the present application tends to be stable and consistent, so that the corresponding light intensity distribution at various locations in the image also tends to be stable and consistent, which is reflected in the better uniformity of the light intensity at various locations in the image.

[0071] It can be seen that in the related art, no matter the light beam passes through the microlens array 200 with a large curvature radius or a small curvature radius, some of the light beams are obviously severely focused, resulting in uneven light distribution and uneven brightness of the image formed by the overall light beam. However, when the light beam passes through the light diffuser 20 of the present application, no matter whether the microlens structure 210 of the microlens array 200 in the light diffuser 20 of the present application has a small curvature radius or a large curvature radius, the propagation path of the light beam after passing through the light diffuser 20 is adjusted, and finally the light distribution of the overall light beam is relatively uniform, which can effectively improve the uniformity of the light intensity distribution by more than 80%, and obviously helps to improve the brightness uniformity of the displayed image.

[0072] Referring to FIG. 5a and FIG. 5b, FIG. 5a shows the intensity distribution of the image formed by the light beam passing through the microlens array 200 of the prior art. FIG. 5b shows the intensity distribution of the image formed by the light beam passing through the light diffuser 20 of an embodiment of the present application. Obviously, in the related art, the light is unevenly distributed after the microlens array 200, and some parts are more focused and the rest are less focused. The brightness uniformity of the image displayed in the related art is poor, such as the image brightness difference in the middle position of the picture, the part between the middle and the periphery, and the periphery position is large, and the overall brightness of the image is uneven. However, FIG. 5b shows that the light distribution after the light passes through the light diffuser 20 in the present application is uniform, and the brightness uniformity of the displayed image is significantly improved. The brightness of the middle position of the picture and the part between the middle and the periphery of the picture tends to be consistent. There is a slight difference in the brightness at the periphery, but the area of ​​the difference is significantly reduced. The overall brightness of the picture is very uniform, and the display effect is obviously greatly improved.

[0073] In some embodiments, the material of the light-transmitting layer 300 can be epoxy resin, acrylic (such as methyl methacrylate type glue), silicon (such as silicone-based glue), oxide, alloy, etc., which is conducive to reducing costs and keeping the refractive index of the light-transmitting layer 300 within the range of 1.4-2.8.

[0074] In some embodiments, the material of the microlens array 200 may be a film material or a liquid material of epoxy resin, acrylic (such as methacrylic adhesive), silicon (such as silicon-based adhesive), etc., which is convenient for maintaining the refractive index of the microlens structure 210 within the range of 1.4-2.8 and for facilitating the preparation of the microlens array 200. The microlens structure 210 of the microlens array 200 may be a convex structure or a concave structure, which may be specifically set according to the deflection requirements of the light, and will not be described in detail here.

[0075] In some embodiments, the material of the base layer 100 can be a plastic material such as polycarbonate (PC), polymethyl methacrylate (PMMA), polyethylene terephthalate (PET), cycloolefin polymer (COP), etc., so that the base layer 100 has good optical properties, heat resistance, and impact resistance, which is conducive to the light passing through the light diffuser 20 having good optical properties.

[0076] In some embodiments, regarding the arrangement of the sub-light-transmitting portion 330 of the light-transmitting layer 300 relative to the microlens array 200, the five embodiments shown in FIG. 2 and FIG. 6 to FIG. 9 can be referred to in combination. FIG. 6 shows a schematic diagram of the structure of the light diffuser 20 of the second embodiment of the present application. FIG. 7 shows a schematic diagram of the structure of the light diffuser 20 of the third embodiment of the present application. FIG. 8 shows a schematic diagram of the structure of the light diffuser 20 of the fourth embodiment of the present application. FIG. 9 shows a schematic diagram of the structure of the light diffuser 20 of the fifth embodiment of the present application.

[0077] In some embodiments, referring to FIG. 2 and FIG. 6 , the microlens array 200 includes a plurality of first microlenses and a plurality of second microlenses, at least one second microlens is disposed between two adjacent first microlenses, and at least one light-transmitting layer 300 includes a plurality of first sub-light-transmitting portions 331 arranged in an array, and the plurality of first sub-light-transmitting portions 331 are disposed on the first microlenses in a one-to-one correspondence. The first microlenses and the second microlenses are both the above-mentioned microlens structures 210, and it can be understood that two adjacent first sub-light-transmitting portions 331 of the plurality of first sub-light-transmitting portions 331 of the light-transmitting layer 300 can be separated by at least one microlens structure 210, and as shown in FIG. 2 , two adjacent first sub-light-transmitting portions 331 can be separated by one microlens structure 210. As shown in FIG. 6 , two adjacent first sub-light-transmitting portions 331 may be spaced apart by two microlens structures 210, or multiple microlens structures 210 (not shown) may be spaced apart by two adjacent first sub-light-transmitting portions 331. That is, a suitable interval between two adjacent first sub-light-transmitting portions 331 may be set based on comprehensive requirements, such as requirements for light adjustment quality and cost control, so as to modulate light through the light-transmitting layer 300 and the microlens array 200.

[0078] In some embodiments, the number m of the second microlenses between two adjacent first microlenses satisfies: m≤10, or in other words, the number of the second microlenses between two adjacent first sub-light-transmitting portions 331 disposed on two adjacent first microlenses satisfies less than or equal to 10. It can be understood that the smaller the interval between the two first sub-light-transmitting portions 331 disposed on two adjacent first microlenses, the better the modulation effect on the overall light beam. In this way, by setting the interval between two adjacent first microlenses to no more than 10 second microlenses, the number of the second microlenses between two adjacent first microlenses can be reasonably adjusted according to the requirements of cost control, light beam modulation effect, etc., so that too many second microlenses between two adjacent first microlenses will not affect the light beam modulation effect.

[0079] In some embodiments, referring to FIG. 7 and FIG. 8, at least one light-transmitting layer 300 further includes a plurality of second sub-light-transmitting portions 332 arranged in an array, and the plurality of second sub-light-transmitting portions 332 are arranged one-to-one on the first microlens or the second microlens. As shown in FIG. 7, the plurality of second sub-light-transmitting portions 332 are arranged one-to-one on the first microlens, and at this time, the second sub-light-transmitting portions 332 are stacked with the first sub-light-transmitting portions 331. As shown in FIG. 8, the plurality of second sub-light-transmitting portions 332 are arranged one-to-one on the second microlens, and at this time, the first sub-light-transmitting portions 331 and the second sub-light-transmitting portions 332 are arranged in sequence along a direction parallel to the substrate layer 100 toward the side of the microlens array 200, or in other words, the first sub-light-transmitting portions 331 and the second sub-light-transmitting portions 332 are equivalent to being arranged in the same layer.

[0080] It can be understood that the first sub-light-transmitting portion 331 and the second sub-light-transmitting portion 332 can be arranged in the same layer or in a stacked arrangement. It can be understood that one of the at least one light-transmitting layer is named as the first light-transmitting layer 310, and the other light-transmitting layer is named as the second light-transmitting layer 320. Then the first light-transmitting layer 310 includes the above-mentioned multiple first sub-light-transmitting portions 331, and the second light-transmitting layer 320 includes the above-mentioned multiple second sub-light-transmitting portions 332. Then the first light-transmitting layer 310 and the second light-transmitting layer 320 can be stacked, as shown in Figure 7, at this time, the first sub-light-transmitting portion 331 of the first light-transmitting layer 310 and the second sub-light-transmitting portion 332 of the second light-transmitting layer 320 are stacked along the direction from the base layer 100 to the microlens array 200. The first light-transmitting layer 310 and the second light-transmitting layer 320 can also be arranged in the same layer, as shown in Figure 8, at this time, the first sub-light-transmitting portion 331 of the first light-transmitting layer 310 and the second sub-light-transmitting portion 332 of the second light-transmitting layer 320 are arranged in the same layer. The multi-layered light-transmitting layer 300 can more precisely control the light deflection, which is more conducive to improving the display effect of the display device 10 using the light diffuser 20 of the present application.

[0081] In some embodiments, as shown in FIG. 9 , at least one light-transmitting layer 300 further includes a second light-transmitting layer 320, and the second light-transmitting layer 320 includes a plurality of second sub-light-transmitting portions 332 arranged in an array, and the plurality of second sub-light-transmitting portions 332 are disposed on the first microlens and the second microlens adjacent to the first microlens. That is, the plurality of sub-light-transmitting portions 330 of the light-transmitting layer 300 are not limited to being disposed on a plurality of spaced microlens structures 210, and the plurality of sub-light-transmitting portions 330 can also be disposed on a plurality of adjacent microlens structures 210. For example, in FIG. 9 , two second sub-light-transmitting portions 332 can be disposed on two adjacent microlens structures 210 to cooperate with the first light-transmitting layer 310 to modulate the degree of light deflection, thereby improving the display effect of the display device 10.

[0082] It can be understood that the sub-light-transmitting portions 330 of the present application can be arranged in an array to improve the uniformity of light deflection modulation and improve the brightness uniformity of the display image.

[0083] In some embodiments, the number of layers a of the light-transmitting layer 300 satisfies: 1≤a≤5, and the thickness h of the sub-light-transmitting portion 330 along the direction of the substrate layer 100 pointing to the microlens array 200 satisfies: h≤2um. In this way, by controlling the number of layers of the light-transmitting layer 300 and the thickness of the sub-light-transmitting portion 330, it is beneficial to control the overall thickness or size of the light diffuser 20, which is beneficial to the lightweight and miniaturized design of the light diffuser 20.

[0084] In some embodiments, refer to FIG. 10, which shows a flow chart of preparing a light diffuser 20 in one embodiment of the present application. The light diffuser 20 of the present application can define the required pattern of the light-transmitting layer 300 on the microlens array 200 by means of photolithography, nanoimprinting, etc., or the light-transmitting layer 300 can be designed to have a plurality of sub-light-transmitting portions 330 according to the requirements, and each sub-light-transmitting portion 330 can have its own pattern, shape, or concave-convex curvature, and the sub-light-transmitting portion 330 of the corresponding shape is formed on the corresponding microlens structure 210 of the microlens array 200 by photolithography, nanoimprinting, etc.

[0085] As shown in FIG10 , a substrate layer 100 is first provided, and a microlens array 200 including a plurality of microlens structures 210 arranged in an array is provided on the substrate layer 100. Then, a light-transmitting material layer is formed on the microlens structure 210 by spin coating, physical or chemical vapor deposition, sputtering, etc. Then, a pattern is embossed by a mold 400, and dried to form the desired light-transmitting layer 300, that is, the pattern of the light-transmitting layer 300 in various embodiments such as FIG2 and FIG6 can be defined by yellow light lithography, nanoimprinting, etc. Finally, demolding is performed to prepare the light diffuser 20 of the present application.

[0086] It can be understood that the above is the process flow for preparing a layer of light-transmitting layer 300. If it is necessary to prepare multiple layers of light-transmitting layers 300, the above process flow is repeated on the basis of preparing the previous layer of light-transmitting layer 300 to continue preparing the next layer of light-transmitting layer 300. For example, if two layers of light-transmitting layers 300, namely a first light-transmitting layer 310 and a second light-transmitting layer 320, are required, after preparing the first light-transmitting layer 310, on this basis, the following steps are performed in sequence: forming a light-transmitting material layer of the second light-transmitting layer 320, defining the pattern of the second light-transmitting layer 320 by means of yellow light lithography, nano-imprinting, etc., and finally demolding.

[0087] The present application can modify the existing microlens array 200 to achieve the effect of cost saving. The present application can select a microlens array 200 with a uniform size of microlens structure 210, and form a light-transmitting layer 300 on the microlens array 200 with a uniform size of microlens structure 210 to achieve the modulation effect of the light beam.

[0088] It can be understood that the preparation of the microlens array 200 with specially designed microlens structures 210 in the related art is relatively complex and has a high preparation cost, while the preparation cost of the microlens array 200 with uniform microlens structures 210 is relatively low and the preparation technology is relatively simple. In combination with the relatively simple technology of preparing the light-transmitting layer 300 by yellow light lithography, nano-imprinting, etc. in the present application, it is further conducive to reducing costs. Therefore, compared with the microlens array 200 with specially designed microlens structures 210 in the related art, the preparation technology threshold of the light diffuser 20 of the present application is significantly reduced, and the cost is significantly controlled.

[0089] The present application also provides a vehicle, which includes the above-mentioned display device 10 and also includes a windshield 14. The light emitted by the light emitting element 11 passes through the light diffuser 20, the first reflective element 12 and the second reflective element 13 in sequence and propagates to the windshield 14 of the vehicle to form an image, so as to project the driving information in front of the driver's line of sight. The vehicle using the display device 10 with the light diffuser 20 of the present application can have a better driving information display effect, better uniformity of brightness at various locations of the driving information display image, and better image clarity.

[0090] The light diffuser 20 of the present application can preliminarily modulate the light emitted by the light emitting element 11 of the display device 10 through the microlens array 200. At the same time, a light-transmitting layer 300 including a plurality of sub-light-transmitting portions 330 is arranged on the light-emitting side of the microlens array 200. The sub-light-transmitting portions 330 are arranged on the corresponding microlens structure 210, and the bending degree of different light rays in the light beam after passing through different microlens structures 210 and the corresponding sub-light-transmitting portions 330 can be changed by designing the thickness and material refractive index of the sub-light-transmitting portions 330 on the corresponding different microlens structures 210. Then, the light distribution in the light beam is adjusted, and the optical path of the light rays passing through different microlens structures 210 is changed, or the optical path difference between the light rays passing through different microlens structures 210 is changed. The optical path difference will affect the distribution of light on the imaging surface, thereby affecting the brightness uniformity of the image. In this way, by changing the optical path difference of light rays between different microlens structures 210 to change the light-emitting path, the uniformity of the brightness of the displayed image can be improved, so that the image can be displayed more clearly.

[0091] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0092] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be construed as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent application shall be subject to the attached claims.

Claims

1. A light diffuser, characterized in that: The light diffuser comprises: Basal layer; a microlens array, disposed on the base layer, the microlens array comprising a plurality of microlens structures arranged in an array; and At least one light-transmitting layer is stacked on the light-emitting side of the microlens array, the light-transmitting layer includes a plurality of sub-light-transmitting portions, the number of which is less than the number of the microlens structures, and the sub-light-transmitting portions are arranged one-to-one on part of the microlens structures.

2. The light diffuser according to claim 1, characterized in that: The microlens array includes a plurality of first microlenses and a plurality of second microlenses, at least one of the second microlenses is arranged between two adjacent first microlenses, at least one layer of the light-transmitting layer includes a plurality of first sub-light-transmitting portions arranged in an array, and the plurality of first sub-light-transmitting portions are arranged on the first microlenses in a one-to-one correspondence.

3. The light diffuser according to claim 2, characterized in that: At least one of the light-transmitting layers further includes a plurality of second sub-light-transmitting portions arranged in an array, and the plurality of second sub-light-transmitting portions are disposed on the first microlenses or the second microlenses in a one-to-one correspondence.

4. The light diffuser according to claim 2, characterized in that: At least one of the light-transmitting layers further includes a plurality of second sub-light-transmitting portions arranged in an array, and the plurality of second sub-light-transmitting portions are disposed on the first microlens and the second microlens adjacent to the first microlens.

5. The light diffuser according to any one of claims 3 to 4, characterized in that: In addition, along the direction from the base layer to the microlens array, the first sub-light-transmissive portion and the second sub-light-transmissive portion may be arranged in the same layer or in a stacked manner.

6. The light diffuser according to claim 2, wherein: The number m of the second microlenses between two adjacent first microlenses satisfies: m≤10.

7. The light diffuser according to claim 1, wherein: The refractive index n1 of the sub-light-transmitting portion and the refractive index n2 of the microlens structure satisfy the following conditions: 1.4≤n1≤2.8, 1.4≤n2≤2.8, and n1-n2≥0.

1.

8. The light diffuser according to claim 1, wherein: The total number of layers a of at least one light-transmitting layer satisfies: 1≤a≤5, and along the direction from the base layer to the microlens array, the thickness h of the sub-light-transmitting portion satisfies: h≤2 um.

9. A display device, characterized in that: It comprises a light emitting element and a light diffuser as claimed in any one of claims 1 to 8, wherein the light diffuser is arranged on the light emitting side of the light emitting element.

10. A vehicle, characterized in that: Comprising the display device as claimed in claim 9.

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