Multi-layer microlens array homogenization structure, design method thereof, TOF lens and equipment

Abstract

The application discloses a kind of multi-layer microlens array light uniformizing structure and its design method, TOF lens and equipment, the multi-layer microlens array light uniformizing structure it includes at least two layers of microlens array, each layer the microlens array is formed by several sublenses arrangement, the optical surface type of several sublenses that form a layer the microlens array is identical;At least one microlens array is formed by several sublenses of even aspheric surface type, several sublenses are misaligned arrangement and form the microlens array;At least one microlens array is formed by several sublenses of deformation aspheric surface type, several sublens arrays are arranged and form the microlens array.The light uniformizing structure disclosed in the application is formed by at least two layers of microlens array, each layer microlens array causes certain diffusion effect to the light emitted by laser array light source, and the diffusion effect caused by the superposition of multiple microlens arrays forms the desired spot and the desired energy distribution.

Description

Technical Field

[0001] This invention relates to the field of three-dimensional perception, and in particular to a multilayer microlens array uniform light structure and its design method, a TOF lens and device. Background Technology

[0002] TOF (Time of Flight) technology can perform three-dimensional perception and distance measurement. The optical part of TOF is mainly divided into three parts: laser array light source, homogenization structure and TOF lens.

[0003] Since the shape, field of view, and energy distribution of the uniform light spot to be achieved by the microlens array in the uniform light structure are specific, the field of view achieved by the existing array laser source after passing through the microlens array is relatively small and cannot meet the requirements of a large detection range.

[0004] When a laser array light source passes through an existing microlens array, interference fringes will appear in the resulting light spot because the coherence of the light emitted by the laser array light source cannot be eliminated by the microlens array.

[0005] Existing microlens arrays are difficult to design and fabricate, making it difficult to create uniform light structures with a large field of view, no interference fringes, and good optical performance.

[0006] Therefore, there is an urgent need to propose a new technical solution to address the above problems. Summary of the Invention

[0007] This invention addresses the problems of interference fringes, small field of view, and high fabrication difficulty in current beam homogenizing devices for laser sources. One aspect proposed is a multilayer microlens array beam homogenizing structure, the specific technical solution of which is as follows:

[0008] A multilayer microlens array uniform light structure includes at least two layers of microlens arrays, each layer of the microlens array being composed of a plurality of sub-lenses arranged together, and the plurality of sub-lenses forming the same layer of the microlens array having the same optical surface shape.

[0009] Furthermore, in the above technical solution, several of the sub-lenses are arranged in a staggered manner to form a layer of the microlens array, wherein the ratio of the maximum to the minimum center distance between two adjacent sub-lenses in the microlens array is no greater than three-half.

[0010] In a preferred embodiment, at least one layer of the microlens array is composed of a plurality of even-order aspherical sublenses, and the plurality of sublenses are arranged in a staggered manner to form the microlens array.

[0011] Furthermore, the radius of curvature of the sub-lenses comprising the several even-order aspherical surface types of the microlens array ranges from 30 μm to 100 μm, and the conic coefficient ranges from -1 to -1.2.

[0012] Furthermore, the radius of curvature of the sub-lenses comprising the several even-order aspherical surface types of the microlens array ranges from 20 μm to 40 μm, and the conic coefficient ranges from -1 to -1.2.

[0013] In a preferred embodiment, at least one layer of the microlens array is composed of a plurality of deformable aspherical sublenses, and the plurality of sublens arrays are arranged to form the microlens array.

[0014] Furthermore, the radius of curvature of the sub-lenses comprising the deformed aspherical surface of the microlens array ranges from 10 μm to 15 μm in the first coordinate direction and from 6 μm to 15 μm in the second coordinate direction. The conic coefficient of the sub-lenses ranges from -1 to -1.2, and the center-to-center distance between any two adjacent sub-lenses ranges from 25 μm to 45 μm.

[0015] Furthermore, the radius of curvature of the sub-lenses comprising the deformed aspherical surface of the microlens array ranges from 10 μm to 20 μm, the conic coefficient of the sub-lenses ranges from -1 to -1.2, and the center-to-center distance between any two adjacent sub-lenses ranges from 25 μm to 45 μm.

[0016] In a preferred embodiment, the multilayer microlens array uniform light structure further comprises two layers of microlens arrays. One layer of the microlens array is composed of a number of even-order aspherical sub-lenses arranged in a staggered manner. The radius of curvature of the number of sub-lenses constituting this layer of the microlens array ranges from 30μm to 100μm, and the conic coefficient ranges from -1 to -1.2.

[0017] Furthermore, the other layer of the microlens array is composed of a plurality of deformed aspherical sublens arrays arranged together. The center-to-center distance between any two adjacent sublenses ranges from 25 μm to 45 μm. The radius of curvature of the plurality of deformed aspherical sublenses constituting the microlens array ranges from 10 μm to 15 μm in the transverse coordinate direction and from 6 μm to 15 μm in the longitudinal coordinate direction. The conic coefficient of the plurality of sublenses ranges from -1 to -1.2.

[0018] In a preferred embodiment, the multilayer microlens array uniform light structure further comprises a three-layer microlens array. The first layer of the microlens array is composed of a number of even-order aspherical sub-lenses arranged in a staggered manner. The radius of curvature of the number of sub-lenses constituting this layer of the microlens array ranges from 30μm to 100μm, and the conic coefficient ranges from -1 to -1.2.

[0019] Furthermore, the second layer of the microlens array is composed of several even-order aspherical sub-lenses arranged in a staggered manner. The radius of curvature of the several sub-lenses that make up this layer of the microlens array ranges from 20μm to 40μm, and the conic coefficient ranges from -1 to -1.2.

[0020] Furthermore, the third layer of the microlens array is composed of a number of deformed aspherical sublens arrays. The center-to-center distance between any two adjacent sublenses ranges from 25μm to 45μm. The radius of curvature of the deformed aspherical sublenses that make up the microlens array ranges from 10μm to 20μm. The conic coefficient of the sublenses ranges from -1 to -1.2.

[0021] In a preferred embodiment, it further includes a substrate layer and a light-diffusing layer formed on the surface of the substrate layer, wherein the light-diffusing layer has the microlens array formed on the surface of the substrate layer opposite to the surface of the substrate layer; the microlens array forms a continuous surface on the surface of the light-diffusing layer.

[0022] Furthermore, the base layers of one layer of the microlens array and the adjacent layer of the microlens array are spaced apart, and the distance between the microlens array and the base layer of the adjacent layer of the microlens array ranges from 0.1 mm to 0.3 mm.

[0023] Furthermore, the optical surface type of the sub-lenses constituting the microlens array includes aspherical surface types.

[0024] Furthermore, the thickness of each layer of the microlens array ranges from 0.2 mm to 0.5 mm.

[0025] On the other hand, the present invention also provides a design method for a multilayer microlens array uniform light structure, which includes: arranging a plurality of sub-lens arrays, determining the center distance between any two adjacent sub-lenses according to the desired light spot; offsetting each sub-lens by a preset distance on its plane with its center point as the initial point, removing the part of the intersection of two adjacent sub-lenses, and obtaining a microlens array.

[0026] In a preferred embodiment, the center-to-center distance between any two adjacent sub-lenses ranges from 25 μm to 45 μm.

[0027] In a preferred embodiment, each sub-lens is offset by a preset distance on its plane with its center point as the initial point. The maximum value of the preset distance offset by each sub-lens is 0.1 times the center distance between the sub-lens at the initial point and its adjacent sub-lens, and the minimum value of the preset distance offset by each sub-lens is 0.

[0028] In another aspect, the present invention also provides a TOF lens, which includes the above-mentioned multilayer microlens array homogenizing structure, wherein the multilayer microlens array homogenizing structure includes at least two layers of microlens array, and an air layer with a thickness ranging from 0.1 mm to 0.5 mm is provided between the microlens array near the laser array light source and the laser array light source.

[0029] In another aspect, the present invention also provides a device equipped with a TOF lens, which includes the aforementioned TOF lens, wherein the aforementioned multilayer microlens array light-uniforming structure is mounted on the TOF lens.

[0030] Compared with the prior art, the present invention has one or more of the following beneficial effects:

[0031] 1. The multilayer microlens array homogenizing structure of the present invention consists of two or more layers of microlens arrays. Each layer of microlens array causes a certain diffusion effect on the light emitted by the laser array light source. The diffusion effect caused by the multilayer microlens array is superimposed to form the desired light spot and the desired energy distribution. The multilayer microlens array homogenizing structure proposed in the present invention can destroy the coherence of the laser passing through the multilayer microlens array structure, so that the light spot has no interference fringes.

[0032] 2. The multilayer microlens array homogenizing structure provided by the present invention has at least one layer of microlens array that irregularly misaligns the sublenses, which further destroys the coherence of the light after the laser array light source passes through the microlens array and eliminates the interference fringes of the light spot.

[0033] 3. In the multilayer microlens array uniform light structure provided by the present invention, the microlens arrays of each layer are closely arranged, and the sub-lenses in each layer of the microlens array have a large radius of curvature and a low sagittal height, which makes them easy to process and reduces the processing difficulty and processing error.

[0034] 4. The multilayer microlens array homogenizing structure provided by the present invention can enable the light emitted by the laser array to obtain a larger field of view after passing through the multilayer microlens array homogenizing structure when the sub-lens has a large radius of curvature, so that the TOF module can detect more areas.

[0035] 5. In the multilayer microlens array uniform light structure provided by the present invention, there are no breaks between the sub-lenses of each layer, and the transition is smooth, forming a continuous surface, which improves the light transmittance and the printing yield during the processing. Attached Figure Description

[0036] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0037] Figure 1 This is a schematic diagram of a light-uniforming structure with a two-layer microlens array;

[0038] Figure 2 This is a side view of a double-layer microlens array structure;

[0039] Figure 3 This is a front view of one layer of the microlens array in a double-layer microlens array structure.

[0040] Figure 4 for Figure 3 A partially enlarged view of the microlens array shown in the diagram;

[0041] Figure 5 This is a front view of the other microlens array in the double-layer microlens array structure.

[0042] Figure 6(a) is a schematic diagram of the far-field emitted light spot of the multilayer microlens array homogenizing structure;

[0043] Figure 6(b) is the grayscale energy ratio diagram corresponding to the light spot schematic diagram shown in Figure 6(a);

[0044] Figure 7 This is a side view of a double-layer microlens array structure;

[0045] Figure 8 This is a front view of one layer of the microlens array in a double-layer microlens array structure.

[0046] Figure 9 for Figure 8 A partially enlarged view of the microlens array shown in the diagram;

[0047] Figure 10 This is a front view of the other microlens array in the double-layer microlens array structure.

[0048] Figure 11(a) is a schematic diagram of the far-field emitted light spot of the multilayer microlens array homogenizing structure;

[0049] Figure 11(b) is the grayscale energy ratio diagram corresponding to the light spot schematic diagram shown in Figure 11(a);

[0050] Figure 12 This is a side view of a double-layer microlens array structure;

[0051] Figure 13 This is a front view of one layer of the microlens array in a double-layer microlens array structure.

[0052] Figure 14 for Figure 13 A partially enlarged view of the microlens array shown in the diagram;

[0053] Figure 15 This is a front view of the other microlens array in the double-layer microlens array structure.

[0054] Figure 16(a) is a schematic diagram of the far-field emitted light spot of the multilayer microlens array homogenizing structure;

[0055] Figure 16(b) is the grayscale energy ratio diagram corresponding to the light spot schematic diagram shown in Figure 16(a);

[0056] Figure 17 This is a side view of a three-layer microlens array structure;

[0057] Figure 18 This is a front view of the first layer of the microlens array in the three-layer microlens array structure.

[0058] Figure 19 for Figure 18 A partially enlarged view of the microlens array shown in the diagram;

[0059] Figure 20 This is a front view of the second microlens array in a three-layer microlens array structure.

[0060] Figure 21 This is a front view of the third microlens array in a three-layer microlens array structure.

[0061] Figure 22(a) is a schematic diagram of the far-field emitted light spot of the three-layer microlens array homogenizing structure;

[0062] Figure 22(b) is the grayscale energy ratio diagram corresponding to the light spot schematic diagram shown in Figure 22(a). Detailed Implementation

[0063] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0064] The essence of the present invention will be further explained below with reference to the accompanying drawings and embodiments.

[0065] Example 1

[0066] Please see Figure 1 , Figure 1 A homogenizing structure with two microlens arrays is schematically illustrated. In this diagram, 100 represents the homogenizing structure with a two-layer microlens array, 110 represents the first homogenizing layer, 111 represents the base layer of the first homogenizing layer, 112 represents the homogenizing layer of the first homogenizing layer, and 113 represents the microlens array of the first homogenizing layer; 120 represents the second homogenizing layer, 121 represents the base layer of the second homogenizing layer, 122 represents the homogenizing layer of the second homogenizing layer, and 123 represents the microlens array of the second homogenizing layer. D represents the spacing between the first and second homogenizing layers.

[0067] In one embodiment, the multilayer microlens array light-uniformation structure of the present invention can be a light-uniformation structure with two layers of microlens arrays (double-layer microlens array light-uniformation structure), and so on. Figure 1 Each light-uniform structure includes a base layer and a light-uniform layer formed on the surface of the base layer. The surface of the light-uniform layer opposite to the base layer has the microlens array, and the microlens array forms a continuous surface on the surface of the light-uniform layer. Figure 1 In the light-homing structure, the first layer 110 and the second layer 120 are arranged at relative intervals. In specific applications, the microlens arrays 113 and 123 of the first and second layers of the light-homing structure both face the laser array light source. The light emitted from the laser array light source passes through the microlens arrays 113 and 123 sequentially, undergoing two diffusions. Similarly, the arrangement of the multi-layer microlens array light-homing structure is also arranged in multiple layers at intervals, allowing the light to pass through multiple microlens arrays sequentially and undergo multiple diffusions, resulting in more uniform light and no interference fringes.

[0068] In one embodiment, each layer of the microlens array is composed of a plurality of sub-lenses arranged in a manner that the sub-lenses in the same layer of the microlens array have the same optical surface shape, which includes even-order aspherical or deformed aspherical surface shapes.

[0069] In one embodiment, the substrate layers of one layer of the microlens array and another adjacent layer of the microlens array are spaced apart (in actual implementation, one layer of the microlens array and another layer of the microlens array can be connected by mechanical means to form a fixed interval), and the distance between the intervals ranges from 0.1 mm to 0.3 mm. Please refer to... Figure 1 , Figure 1The light-uniform structure 100 includes two microlens arrays. Each microlens array is disposed on one side surface of the light-uniform layer. The microlens array 123 of the second light-uniform structure 120 is disposed opposite to the base layer 111 of the first light-uniform structure 110 to form a spacer layer (which can be understood as an air layer, a vacuum layer, or a medium layer with a refractive index that matches the actual application). The thickness D of the spacer layer is 0.1 mm to 0.3 mm.

[0070] In one embodiment, the thickness of each layer of the microlens array ranges from 0.2 mm to 0.5 mm.

[0071] In one embodiment, see further. Figure 1 The multilayer microlens array homogenizing structure of this invention comprises two layers of microlens arrays. The first layer consists of a plurality of even-order aspherical sub-lenses arranged in a staggered manner. The radius of curvature of the plurality of sub-lenses comprising this layer ranges from 30 μm to 100 μm, and the conic coefficient ranges from -1 to -1.2. The staggered arrangement of the plurality of even-order aspherical sub-lenses can be understood as an irregular arrangement of multiple sub-lenses with random boundary shapes. However, the irregular arrangement of multiple sub-lenses can form a continuous surface, i.e., the resulting microlens array is continuous and uninterrupted. Of course, the irregular arrangement of multiple sub-lenses can also be obtained through random arrangement, or by first arranging them in an array and then randomly shuffling the result to form an irregular arrangement.

[0072] The other layer of the two-layer microlens array consists of a plurality of deformable aspherical sub-lens arrays. The center-to-center distance between any two adjacent sub-lenses ranges from 25 μm to 45 μm. The radius of curvature of the deformable aspherical sub-lenses constituting the microlens array ranges from 10 μm to 15 μm in the lateral direction and from 6 μm to 15 μm in the longitudinal direction. The conic coefficient of the sub-lenses ranges from -1 to -1.2. The arrangement of the deformable aspherical sub-lens arrays is actually an operation method of arranging and combining multiple sub-lenses according to a specific order or rule, such as arranging the arrays in a matrix or honeycomb pattern.

[0073] The reference formula for the even-order aspherical surface sub-lens of the present invention is as follows:

[0074]

[0075] Where Z is the sagitta of the sub-lens, c is the curvature of the sub-lens, r is the radial coordinate of the sub-lens, K is the conic coefficient of the sub-lens, and a1-a8 represent the even-order aspherical coefficients of the even-order aspherical surfaces.

[0076] In one embodiment, the microlens array consists of a plurality of even-order aspherical sub-lenses arranged in a staggered manner, and the staggered arrangement can be performed according to the following steps:

[0077] 1. Arrange the sub-lenses in an array, with the center-to-center distance between adjacent sub-lenses denoted as L. Fix the center-to-center distance between each sub-lens. Arranging the sub-lenses in an array means arranging the sub-lenses into a matrix. This step involves arranging several sub-lenses to form a matrix-arranged microlens array.

[0078] 2. Randomly offset the center of each sub-lens by a distance H, where H ranges from 0 to 0.1*L, thus fixing the offset range but making the offset direction random. This step involves offsetting each sub-lens in the matrix-arranged microlens array by a preset distance in a random direction to form a staggered microlens array.

[0079] 3. Take the union of all the sub-lenses after random offset and remove the overlapping parts between the sub-lenses. This process forms a continuous surface from the misaligned microlens array. The resulting microlens array has one or more continuous surfaces. The shapes of the sub-lenses that make up the microlens array with continuous surfaces are random, such as quadrilaterals, pentagons, hexagons, or other arbitrary polygons.

[0080] In step 2 above, the center of each sub-lens is randomly offset by a value H, where H ranges from 0 to 0.1*L. Therefore, in the staggered microlens array, the ratio of the maximum to the minimum center distance between two adjacent sub-lenses is at most three-half. For example, if the center distance between two adjacent sub-lenses in the array is L1, then after randomly offsetting these two sub-lenses, the maximum center distance is 1.2*L1 (i.e., the two sub-lenses move in opposite directions by 0.1*L1, resulting in a distance of 1.2*L1 after random offset); the minimum center distance is 0.8*L1 (i.e., the two sub-lenses move towards each other by 0.1*L1, resulting in a distance of 0.8*L1 after random offset). In other words, the ratio of the maximum to the minimum center distance between two adjacent sub-lenses is no greater than (1.2*L1) / (0.8*L1).

[0081] The aforementioned "the other layer of the two-layer microlens array is composed of a plurality of deformed aspherical sub-lens arrays" refers to the following formula for the deformed aspherical sub-lenses:

[0082]

[0083] Where Z is the sag of the sub-lens, Cx is the curvature of the sub-lens in the X direction, Cy is the curvature of the sub-lens in the y direction, and A... 2n With B 2nFor deformable aspherical surfaces, the aspherical coefficient is denoted as .

[0084] The uniform light structure described in this embodiment diffuses the light emitted from the laser array source through two layers of microlens arrays. The superposition of the diffusion effect disrupts the coherence of the laser passing through the multi-layer microlens array structure, resulting in a light spot without interference fringes. It also allows the sub-lenses to achieve a larger field of view after the light emitted from the laser array source passes through the two layers of microlens arrays, even when the sub-lenses have a large radius of curvature, so that the TOF module can detect more areas. Furthermore, there are no discontinuities between the sub-lenses in each layer of the microlens array, resulting in a smooth transition, which improves light transmittance and the printing yield during the processing.

[0085] Example 2

[0086] In one embodiment, the multilayer microlens array homogenizing structure of the present invention can be a homogenizing structure with a three-layer microlens array, i.e., with... Figure 1 Similarly, in Figure 1 Based on this, a uniform light structure layer is added, thus forming a three-layer microlens array.

[0087] In one embodiment, in the three-layer microlens array, the first layer of the microlens array is composed of a plurality of even-order aspherical sub-lenses arranged in a staggered manner, wherein the radius of curvature of the plurality of sub-lenses comprising this layer of the microlens array ranges from 30μm to 100μm, and the conic coefficient ranges from -1 to -1.2; the second layer of the microlens array is composed of a plurality of even-order aspherical sub-lenses arranged in a staggered manner, wherein the radius of curvature of the plurality of sub-lenses comprising this layer of the microlens array ranges from 20μm to 40μm, and the conic coefficient ranges from -1 to -1.2; the third layer of the microlens array is composed of a plurality of deformed aspherical sub-lenses arranged in a sub-lens array, wherein the center distance between any two adjacent sub-lenses ranges from 25μm to 45μm, the radius of curvature of the plurality of deformed aspherical sub-lenses comprising this layer of the microlens array ranges from 10μm to 20μm, and the conic coefficient of the plurality of sub-lenses ranges from -1 to -1.2.

[0088] The microlens array in the first layer and the microlens array in the second layer are both composed of a number of even-order aspherical sublenses arranged in a staggered manner. The staggered arrangement method used can be the same as the arrangement method described in Example 1, and will not be repeated here.

[0089] The uniform light structure of the three-layer microlens array provided in this embodiment destroys the coherence of the laser through the superposition of multiple diffusion effects, so that there are no interference fringes in the light spot and a larger field of view can be obtained, thus expanding the area detected by the TOF module.

[0090] The embodiments of this invention only provide examples of a double-layer microlens array light-uniformation structure and a three-layer microlens array light-uniformation structure. However, the multi-layer microlens array light-uniformation structure provided by this invention is by no means limited to the single-layer and three-layer structures described in the embodiments. Those skilled in the art can also obtain other technical solutions for multi-layer microlens array light-uniformation structures based on the technical solutions provided by this invention. These embodiments of this invention will not be described one by one.

[0091] According to the multilayer microlens array light-uniformation structure of the present invention, the present invention also provides a TOF lens, which includes the above-mentioned multilayer microlens array light-uniformation structure. The multilayer microlens array light-uniformation structure includes at least two layers of microlens arrays, and an air layer with a thickness ranging from 0.1 mm to 0.5 mm is provided between the microlens array near the laser array light source and the laser array light source.

[0092] The present invention also provides a device equipped with a TOF lens, which includes the above-mentioned TOF lens, and the above-mentioned multilayer microlens array light-uniforming structure is mounted on the TOF lens.

[0093] Example 3:

[0094] This invention proposes a multilayer microlens array homogenizing structure, combined with Figure 2 To Figure 6, Figure 2 This is a side view of a double-layer microlens array structure; Figure 3 This is a front view of one layer of the microlens array in a double-layer microlens array structure. Figure 4 for Figure 3 A partially enlarged view of the microlens array shown in the image; Figure 5 Figure 6(a) is a front view of the other microlens array in the double-layer microlens array structure; Figure 6(b) is a schematic diagram of the far-field emitted light spot of the multi-layer microlens array homogenizing structure; Figure 6(a) is a gray-scale energy ratio diagram corresponding to the light spot schematic diagram shown in Figure 6(a).

[0095] Among them, 30-double-layer microlens array uniform light structure; 31-first layer microlens array; 32-second layer microlens array; 33-laser array light source.

[0096] In this embodiment, the dual-layer microlens array homogenizing structure of the present invention includes two layers of microlens arrays, namely a first layer microlens array 31 and a second layer microlens array 32. The optical surface of the first layer microlens array 31 is an even-order aspherical surface, and the sub-lenses constituting the first layer microlens array 31 have a radius of curvature of 100 μm and a conic coefficient of -1.02. The optical surface of the second layer microlens array 32 is a deformed aspherical surface, and the sub-lenses constituting the second layer microlens array 32 have a radius of curvature of 14.2 μm and a conic coefficient of -1.02 in the lateral direction and a radius of curvature of 8.7 μm and a conic coefficient of -1.02 in the longitudinal direction.

[0097] The first microlens array 31 faces the laser array light source 33 directly, and the distance between them is 0.1 mm. The substrate layer on which the first microlens array 31 is attached and the second microlens array 32 are arranged opposite each other to form a spacer layer with a thickness of 0.2 mm.

[0098] Referring to Figures 6(a) and 6(b), when the laser array light source passes through the double-layer microlens array homogenizing structure described in this embodiment, the resulting diffused light spot is a rectangular ring-shaped light spot. The energy in the X direction reaches its peak at a field of view of 65 degrees, and the energy in the Y direction reaches its peak at a field of view of 38 degrees. The energy in the X direction decreases to half of its peak at a field of view of 80 degrees, and the energy in the Y direction decreases to half of its peak at a field of view of 57 degrees (the figure shows the projected light spot at a distance of 250 mm. By converting the linear quantity of the light spot into an angular quantity and then analyzing the grayscale ratio at each angular quantity, the energy peak information described in this embodiment can be obtained).

[0099] In this embodiment, see Figure 4 In the dual-layer microlens array uniform light structure described in this embodiment, the transition between two adjacent sub-lenses in each layer of the microlens array is smooth, there are no breaks at the connection, and the fill rate is 100%.

[0100] Example 4:

[0101] This invention proposes a multilayer microlens array homogenizing structure, combined with Figures 7 to 1 1, Figure 7 This is a side view of a double-layer microlens array structure; Figure 8 This is a front view of one layer of the microlens array in a double-layer microlens array structure. Figure 9 for Figure 8 A partially enlarged view of the microlens array shown in the image; Figure 10 Figure 11(a) is a front view of the other microlens array in the double-layer microlens array structure; Figure 11(b) is a schematic diagram of the far-field emitted light spot of the multi-layer microlens array homogenizing structure; Figure 11(b) is the gray-scale energy ratio diagram corresponding to the light spot schematic diagram shown in Figure 11(a).

[0102] Among them, 40-double-layer microlens array uniform light structure; 41-first layer microlens array; 42-second layer microlens array; 43-laser array light source.

[0103] In this embodiment, the dual-layer microlens array homogenizing structure of the present invention includes two layers of microlens arrays, namely a first layer microlens array 41 and a second layer microlens array 42. The optical surface of the first layer microlens array 41 is an even-order aspherical surface, and the sub-lenses constituting the first layer microlens array 41 have a radius of curvature of 50 μm and a conic coefficient of -1.1. The optical surface of the second layer microlens array 42 is a deformed aspherical surface, and the sub-lenses constituting the second layer microlens array 42 have a radius of curvature of 14 μm in the lateral direction and a conic coefficient of -1.02; and a radius of curvature of 8.7 μm in the longitudinal direction and a conic coefficient of -1.02.

[0104] The first microlens array 41 faces the laser array light source 43 directly, and the distance between them is 0.1 mm. The substrate layer on which the first microlens array 41 is attached and the second microlens array 42 are arranged opposite each other to form a spacer layer with a thickness of 0.2 mm.

[0105] Referring to Figures 11(a) and 11(b), when the laser array light source passes through the double-layer microlens array homogenizing structure described in this embodiment, the resulting diffused light spot is a rectangular ring light spot. The energy in the X direction reaches its peak at a field of view of 64 degrees, and the energy in the Y direction reaches its peak at a field of view of 38 degrees. The energy in the X direction decreases to half of its peak value at a field of view of 80 degrees, and the energy in the Y direction decreases to half of its peak value at a field of view of 55 degrees.

[0106] In this embodiment, see Figure 9 In the dual-layer microlens array uniform light structure described in this embodiment, the transition between two adjacent sub-lenses in each layer of the microlens array is smooth, there are no breaks at the connection, and the fill rate is 100%.

[0107] Example 5:

[0108] This invention proposes a multilayer microlens array homogenizing structure, combined with Figures 12 to 1 6, Figure 12 This is a side view of a double-layer microlens array structure; Figure 13 This is a front view of one layer of the microlens array in a double-layer microlens array structure. Figure 14 for Figure 13 A partially enlarged view of the microlens array shown in the image;

[0109] Figure 15 Figure 16(a) is a front view of another layer of the microlens array in the double-layer microlens array structure; Figure 16(b) is a schematic diagram of the far-field emitted light spot of the multi-layer microlens array homogenizing structure; Figure 16(b) is the gray-scale energy ratio diagram corresponding to the light spot schematic diagram shown in Figure 16(a).

[0110] Among them, 50-double-layer microlens array uniform light structure; 51-first layer microlens array; 52-second layer microlens array; 53-laser array light source.

[0111] In this embodiment, the dual-layer microlens array homogenizing structure of the present invention includes two layers of microlens arrays, namely a first layer microlens array 51 and a second layer microlens array 52. ​​The optical surface of the first layer microlens array 51 is spherical, and the radius of curvature of the sub-lenses constituting the first layer microlens array 51 is 33 μm. The optical surface of the second layer microlens array 52 is deformed aspherical, and the radius of curvature of the sub-lenses constituting the second layer microlens array 52 is 14 μm in the lateral direction and has a conicity of -1.02; the radius of curvature in the longitudinal direction is 8.7 μm and has a conicity of -1.02.

[0112] The first microlens array 51 faces the laser array light source 53 directly, and the distance between them is 0.1 mm. The substrate layer on which the first microlens array 51 is attached and the second microlens array 52 are arranged opposite each other to form a spacer layer with a thickness of 0.2 mm.

[0113] Referring to Figures 16(a) and 16(b), when the laser array light source passes through the double-layer microlens array homogenizing structure described in this embodiment, the resulting diffused light spot is a rectangular ring-shaped light spot. The energy in the X direction reaches its peak at a field of view of 59 degrees, and the energy in the Y direction reaches its peak at a field of view of 35 degrees. The energy in the X direction decreases to half of its peak value at a field of view of 82 degrees, and the energy in the Y direction decreases to half of its peak value at a field of view of 60 degrees.

[0114] In this embodiment, see Figure 14 In the dual-layer microlens array uniform light structure described in this embodiment, the transition between two adjacent sub-lenses in each layer of the microlens array is smooth, there are no breaks at the connection, and the fill rate is 100%.

[0115] Example 6:

[0116] This invention proposes a multilayer microlens array homogenizing structure, combined with Figures 17 to 2 2, Figure 17 This is a side view of a three-layer microlens array structure; Figure 18 This is a front view of the first layer of the microlens array in the three-layer microlens array structure. Figure 19 for Figure 18 A partially enlarged view of the microlens array shown in the diagram; Figure 20 This is a front view of the second microlens array in a three-layer microlens array structure. Figure 21Figure 22(a) is a front view of the third microlens array in the three-layer microlens array structure; Figure 22(b) is a schematic diagram of the far-field emitted light spot of the three-layer microlens array uniform light structure; Figure 22(b) is the gray-scale energy ratio diagram corresponding to the light spot schematic diagram shown in Figure 22(a).

[0117] Among them, 60-double-layer microlens array uniform light structure; 61-first layer microlens array; 62-second layer microlens array; 63-third layer microlens array; 64-laser array light source.

[0118] In this embodiment, the three-layer microlens array homogenizing structure of the present invention includes three layers of microlens arrays, namely a first layer microlens array 61, a second layer microlens array 62, and a third layer microlens array 63. The optical surface types of the first layer microlens array 61 and the second layer microlens array 62 are both even-order aspherical surfaces. The sub-lenses constituting the first layer microlens array 61 have a radius of curvature of 50 μm and a conic coefficient of -1.02; the sub-lenses constituting the second layer microlens array 62 have a radius of curvature of 25 μm and a conic coefficient of -1; the optical surface type of the third layer microlens array 63 is a deformed aspherical surface. The sub-lenses constituting the third layer microlens array 63 have a radius of curvature of 16 μm in the lateral direction and a conic coefficient of -0.98; and a radius of curvature of 12.5 μm in the longitudinal direction and a conic coefficient of -0.98.

[0119] The first microlens array 61 faces the laser array light source 64 directly, and the distance between them is 0.1 mm. The substrate layer on which the first microlens array 61 is attached and the second microlens array 62 are arranged opposite each other to form a spacer layer with a thickness of 0.2 mm.

[0120] Referring to Figures 22(a) and 22(b), when the laser array light source passes through the three-layer microlens array homogenizing structure described in this embodiment, the resulting diffused light spot is a rectangular ring-shaped light spot. The energy in the X direction reaches its peak at a field of view of 50 degrees, and the energy in the Y direction reaches its peak at a field of view of 42 degrees. The energy in the X direction decreases to half of its peak value at a field of view of 67 degrees, and the energy in the Y direction decreases to half of its peak value at a field of view of 52 degrees.

[0121] To achieve the same field of view as a multilayer microlens array, a single-layer microlens array requires sublenses with larger radii of curvature and apertures than multilayer microlens arrays. In actual manufacturing, sublenses with larger radii of curvature and apertures are more difficult to process and imprint. Therefore, the multilayer microlens array homogenizing structure described in this invention reduces manufacturing difficulty while still meeting optical performance and field of view requirements.

[0122] In this embodiment, see Figure 19In the three-layer microlens array uniform light structure described in this embodiment, the transition between two adjacent sub-lenses in each layer of the microlens array is smooth, there are no breaks at the connection, and the fill rate is 100%.

[0123] In summary, compared with the prior art, the multilayer microlens array uniform light structure of the present invention has a large radius of curvature and a low sag of each sub-lens in the multilayer microlens array, which makes it easy to process and reduces the processing difficulty and error.

[0124] In one embodiment, the sub-lenses can be arranged irregularly in the first or second layer of the multilayer microlens array, thereby disrupting the coherence of the light transmitted through the microlens array and eliminating interference fringes of the light spot.

[0125] Furthermore, the multilayer microlens array structure described in this invention allows the light emitted by the laser array to obtain a larger field of view after passing through the multilayer microlens array when the sub-lenses have a large radius of curvature, so that the TOF module can detect more areas; and there are no breaks between the sub-lenses in each layer of the microlens array, with smooth transitions, which improves light transmittance and the printing yield during the processing.

[0126] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. In addition, those skilled in the art can combine and integrate the different embodiments or examples described in this specification.

[0127] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications and variations to the above embodiments within the scope of the present invention.

Claims

1. A multilayer microlens array light-uniforming structure, characterized in that, It comprises at least two layers of microlens arrays, each layer of which consists of a plurality of sublenses arranged in a manner. The optical surface shapes of several sub-lenses that make up the same layer of the microlens array are the same; At least one layer of the microlens array is composed of several deformable aspherical sublenses, and the several deformable aspherical sublens arrays are arranged to form the microlens array; The formula for the sub-lens of deformable aspherical surface type is as follows: ， Where Z is the sag of the deformed aspherical sublens, Cx is the curvature of the deformed aspherical sublens in the X direction, Cy is the curvature of the deformed aspherical sublens in the y direction, and A... 2n With B 2n k is the aspheric coefficient of the deformable aspheric surface. x With k y These are the conic constants representing the degree to which the deformable aspherical sub-lens deviates from the spherical surface in the X and Y directions, respectively; The sub-lenses comprising the deformed aspherical surface type of the microlens array have radii of curvature ranging from 10 μm to 15 μm in the first coordinate direction and from 6 μm to 15 μm in the second coordinate direction. The conic coefficients of several deformed aspherical sub-lenses range from -1 to -1.

2. The center-to-center distance between any two adjacent deformed aspherical sub-lenses ranges from 25 μm to 45 μm; At least one layer of the microlens array is composed of several even-order aspherical surface sub-lenses, and the several even-order aspherical surface sub-lenses are arranged in a staggered manner to form the microlens array; The radii of curvature of the sub-lenses comprising the several even-order aspherical surface types of the microlens array range from 30 μm to 100 μm, and the conic coefficient ranges from -1 to -1.2; or The radius of curvature of the sub-lenses comprising the several even-order aspherical surface types of the microlens array ranges from 20 μm to 40 μm, and the conic coefficient ranges from -1 to -1.

2.

2. The multilayer microlens array homogenizing structure according to claim 1, characterized in that, A number of sub-lenses in each layer are staggered to form a layer of microlens array. In the microlens array, the ratio of the maximum to the minimum center distance between two adjacent sub-lenses is no greater than three-half.

3. The multilayer microlens array homogenizing structure according to claim 1, characterized in that, The multilayer microlens array uniform light structure includes two layers of microlens arrays. One layer of the microlens array is composed of several even-order aspherical sub-lenses arranged in a staggered manner. The radius of curvature of the several sub-lenses that make up this layer of the microlens array ranges from 30μm to 100μm, and the conic coefficient ranges from -1 to -1.

2. The other layer of the microlens array consists of a number of sub-lens arrays with deformed aspherical surfaces.

4. The multilayer microlens array homogenizing structure according to claim 1, characterized in that, The multilayer microlens array uniform light structure includes three layers of microlens array. The first layer of the microlens array is composed of several even-order aspherical sub-lenses arranged in a staggered manner. The radius of curvature of the several sub-lenses that make up this layer of the microlens array ranges from 30μm to 100μm, and the conic coefficient ranges from -1 to -1.

2. The second layer of the microlens array is composed of several even-order aspherical sub-lenses arranged in a staggered manner. The radius of curvature of the several sub-lenses that make up this layer of the microlens array ranges from 20μm to 40μm, and the conic coefficient ranges from -1 to -1.

2. The third layer of the microlens array is composed of several deformed aspherical sublens arrays. The center distance between any two adjacent sublenses ranges from 25μm to 45μm. The radius of curvature of the deformed aspherical sublenses that make up the microlens array ranges from 10μm to 15μm. The conic coefficient of the sublenses ranges from -1 to -1.

2.

5. The multilayer microlens array homogenizing structure according to claim 1, characterized in that, It also includes a substrate layer and a light-diffusing layer formed on the surface of the substrate layer, wherein the microlens array is formed on the surface of the light-diffusing layer opposite to the surface of the substrate layer; The microlens array forms a continuous surface on the surface of the light-diffusing layer; The base layers of one layer of the microlens array and the adjacent layer of the microlens array are spaced apart, and the distance between the microlens array and the base layer of the adjacent layer of the microlens array ranges from 0.1 mm to 0.3 mm. The thickness of each layer of the microlens array ranges from 0.2 mm to 0.5 mm.

6. A design method for a multilayer microlens array homogenizing structure as described in any one of claims 1-5, characterized in that, It includes: Arrange several sub-lens arrays for each layer, and determine the center distance between any two adjacent sub-lenses according to the desired light spot. Each sub-lens is offset by a preset distance on its plane with its center point as the initial point, and the intersecting part of two adjacent sub-lenses is removed to obtain a microlens array.

7. The design method of the multilayer microlens array homogenizing structure according to claim 6, characterized in that, The center-to-center distance between any two adjacent sub-lenses ranges from 25 μm to 45 μm; Each sub-lens is offset by a preset distance on its plane, with its center point as the initial point. The maximum value of the preset distance offset for each sub-lens is 0.1 times the center-to-center distance between the sub-lens at the initial point and its adjacent sub-lens. The minimum value of the preset distance for each sub-lens offset is 0.

8. A TOF lens, characterized in that, It includes the multilayer microlens array light-uniforming structure according to any one of claims 1-5, wherein the multilayer microlens array light-uniforming structure includes at least two layers of microlens array, and an air layer with a thickness ranging from 0.1 mm to 0.5 mm is provided between the microlens array near the laser array light source and the laser array light source.

9. A device equipped with a TOF lens, characterized in that, It includes the TOF lens as described in claim 8, wherein the TOF lens is equipped with a multilayer microlens array light-uniforming structure as described in any one of claims 1-5.

Images