Micro-lens array homogenization structure and manufacturing method thereof, TOF lens and equipment

Abstract

The application discloses a kind of micro microlens array light uniformization structure and its manufacturing method, TOF lens and equipment, including substrate layer, and the light uniformization layer formed on the surface of substrate layer, the surface of the light uniformization layer is formed with lens array group away from substrate layer, several microlenses are misaligned arrangement and form the lens array group, the lens array group is formed on the surface of the light uniformization layer Continuous surface, the several microlenses are arranged in groups, and the microlenses of one group in adjacent two groups are arranged in groups, and the microlenses of another group in adjacent two groups are arranged in groups, the curvature radius of the microlenses of one group is arranged according to the rule that gradually increases from middle to both ends, and the curvature radius of the microlenses of another group is arranged according to the rule that gradually decreases from middle to both ends.The light uniformization structure disclosed in the application is composed of microlenses with different apertures and shapes, destroys the periodicity of microlens array, eliminates interference phenomenon after laser array passes through the light uniformization structure, and reduces the processing difficulty of nanoimprint.

Description

Technical Field

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

[0002] Time-of-flight (TOF) technology enables 3D perception and distance measurement. The optical components of TOF mainly consist of three parts: a laser array light source, a homogenizing structure, and a TOF lens. As TOF technology is increasingly incorporated into miniaturized devices, TOF lenses are becoming smaller. Correspondingly, the homogenizing structure of the TOF lens, as a crucial component of TOF technology, also needs to conform to this miniaturization trend. However, existing miniature homogenizing structures cannot achieve the required field of view for TOF technology and exhibit interference phenomena, affecting the TOF lens's reception of the light field.

[0003] Furthermore, the boundaries between microlenses in existing micro-uniform light microlens array structures are not clearly defined, and the structure is relatively deep, which makes it difficult to perform grayscale compensation well during photolithography.

[0004] Even worse, existing micro-beam homogenizing microlens array structures cannot meet the needs of miniaturized devices such as mobile phones and tablets for beam homogenizing devices, thus creating a technological blind spot.

[0005] Therefore, there is an urgent need to propose a new technical solution to address the above problems. Summary of the Invention

[0006] The purpose of this invention is to solve the problems existing in the prior art. On the one hand, it provides a micro-microlens array light-uniforming structure, the specific technical solution of which is as follows:

[0007] A microlens array light-uniforming structure includes a substrate layer and a light-uniforming layer formed on the surface of the substrate layer, wherein a lens array is formed on the surface of the light-uniforming layer opposite to the substrate layer.

[0008] A plurality of microlenses are arranged in a staggered manner to form the lens array group, and the lens array group forms a continuous surface on the surface of the homogenizing layer.

[0009] The plurality of microlenses are arranged in multiple adjacent groups, with two adjacent groups forming an interval group. The radius of curvature of the microlenses in one of the two adjacent groups is arranged in a pattern that gradually increases from the middle to both ends, while the radius of curvature of the microlenses in the other of the two adjacent groups is arranged in a pattern that gradually decreases from the middle to both ends.

[0010] In a further embodiment, the substrate layer is a light-transmitting glass substrate, the refractive index of the substrate layer is greater than or equal to 1.4, and the transmittance of the substrate layer for light in the 930nm-940nm wavelength band is greater than or equal to 90%.

[0011] Furthermore, the light-diffusing layer is a molding adhesive layer, which is adhered to the light-transmitting glass substrate.

[0012] Furthermore, the molding adhesive layer includes photoresist and / or imprinting adhesive;

[0013] Furthermore, the thickness of the light-transmitting glass substrate ranges from 0.3mm to 0.6mm, and the thickness of the molding adhesive layer ranges from 0.03mm to 0.1mm.

[0014] In a further embodiment, the microlenses constituting the lens array group are all aspherical microlenses, and the radius of curvature of the aspherical microlenses ranges from 5μm to 300μm.

[0015] Furthermore, the shapes of the microlenses that make up the lens array group are basically different, and the shapes of the microlenses include one or more combinations of triangles, quadrilaterals, pentagons, and hexagons.

[0016] In a further embodiment, the lens array group has several columns, and the center-to-center distance between two adjacent microlenses in any column is 25μm-120μm;

[0017] Furthermore, within one of the interval groups, the radius of curvature of the microlens array group is random;

[0018] Furthermore, within one of the interval groups, the distance between the centers of two adjacent microlenses is determined by the radius of curvature selected for the corresponding two microlenses and the desired shape of the light spot.

[0019] Furthermore, the larger the radius of curvature of the two microlenses, the larger the distance between the centers of the two adjacent microlenses, and the longer the length of the light spot shape in the direction of the line connecting the centers of the two adjacent microlenses. If the radius of curvature of the two microlenses is fixed, and it is required that the length of the light spot shape in the direction of the line connecting the centers of the two adjacent microlenses be as long as possible, then the distance between the centers of the two adjacent microlenses is larger.

[0020] In a further embodiment, the distance between the two said spacing groups is determined by the desired shape of the light spot and the maximum and minimum radii of curvature of the microlenses in each said spacing group.

[0021] In a further embodiment, if the number of microlenses in one of two adjacent groups is N, and the number of microlenses in the other of the two adjacent groups is M,

[0022] then, when N > M, the lens curvature radius of the group with M microlenses is greater than the lens curvature radius of the group with N microlenses;

[0023] when N < M, the lens curvature radius of the group with M microlenses is less than the lens curvature radius of the group with N microlenses;

[0024] wherein, the values of M and N include integers within 2 to 10, and the values of M and N are adjacent integers.

[0025] In a further embodiment, within one of the spacer groups, the range of values of the curvature radius of the microlenses determines the number of microlenses within that spacer group. The larger the range of values of the curvature radius of the microlenses, the more microlenses there are within that spacer group.

[0026] In a further embodiment, after undergoing a de-spacing process, a number of the microlenses within the lens array group form a continuous surface on the surface of the light homogenizing layer.

[0027] On the other hand, the present invention also provides a method for manufacturing a micro microlens array light homogenizing structure, including:

[0028] Providing a base layer, the base layer being a light-transmitting glass sheet;

[0029] Providing a pattern forming template, on the surface of the pattern forming template there is formed a first pattern structure, the first pattern structure being opposite in structure to the micro microlens array pattern;

[0030] Providing a shaping adhesive, using the pattern forming template as a mold, and by imprinting, shaping the shaping adhesive onto the base layer, and forming the micro microlens array pattern on the surface of the base layer to obtain the micro microlens array light homogenizing structure.

[0031] In a further embodiment, the method for manufacturing the pattern forming template specifically includes:

[0032] Providing a pattern forming layer, on the surface of the pattern forming layer there is formed a second pattern structure, the second pattern structure being consistent in structure with the micro microlens array pattern;

[0033] Furthermore, providing a pattern transfer layer, using the pattern forming layer as a template, and by imprinting, shaping the shaping adhesive onto the pattern transfer layer, and forming the first pattern structure on the surface of the pattern transfer layer to obtain the pattern forming template.

[0034] In a further embodiment, the first pattern structure is formed by diamond turning technology to obtain the pattern forming template;

[0035] Furthermore, the pattern forming template is a metal template.

[0036] In a further embodiment, a second pattern structure is formed on the surface of the pattern forming layer using diamond turning technology.

[0037] In a further embodiment, a second pattern structure is formed on the surface of the pattern forming layer, specifically including:

[0038] Photoresist is uniformly spin-coated onto the surface of the pattern forming layer to form a photoresist layer with a thickness of 5μm-50μm.

[0039] The photoresist layer is exposed to multiple times at different gray levels, and gray level compensation is performed to form the second pattern structure on the surface of the pattern forming layer.

[0040] In a further embodiment, a second pattern structure is formed on the surface of the pattern forming layer, specifically including:

[0041] The pattern forming layer is immersed in a photosensitive resin, and the photosensitive resin is exposed to different gray levels multiple times to form the second pattern structure on the surface of the pattern forming layer.

[0042] In a further embodiment, the thickness of the substrate layer ranges from 0.3 mm to 0.6 mm.

[0043] Furthermore, the refractive index of the substrate layer is greater than or equal to 1.4, and the transmittance of the substrate layer for light in the 930nm-940nm wavelength band is greater than or equal to 90%.

[0044] Furthermore, the microlens array pattern comprises a plurality of microlenses arranged without spacing.

[0045] Furthermore, the refractive index of the molding compound is greater than or equal to 1.4.

[0046] Furthermore, the molding compound is made of resin.

[0047] In a further embodiment, the method for designing and fabricating the microlens array pattern of the present invention may specifically include:

[0048] Several microlenses are arranged in multiple adjacent groups, with two adjacent groups forming an interval group. The radius of curvature of the microlenses in one of the two adjacent groups is arranged in a pattern that gradually increases from the middle to both ends, while the radius of curvature of the microlenses in the other of the two adjacent groups is arranged in a pattern that gradually decreases from the middle to both ends.

[0049] If the number of microlenses in one of the adjacent two groups is N, and the number of microlenses in the other of the adjacent two groups is M,

[0050] then, when N > M, the lens curvature radius of the group with M microlenses is greater than that of the group with N microlenses;

[0051] When N < M, the lens curvature radius of the group with M microlenses is less than that of the group with N microlenses;

[0052] wherein, the values of M and N include integers within 2 to 10, and the values of M and N are adjacent integers.

[0053] Further, the micro-microlens array pattern includes a plurality of the spacer groups, and the plurality of spacer groups form a lens array group. The center-to-center distance between two adjacent microlenses within one spacer group is 25 μm - 120 μm.

[0054] Further, the plurality of microlenses are arranged in a matrix through gaps, and the connection lines of the centers of any column of microlenses in the matrix form a straight line.

[0055] Further, de-spacing processing is performed on the plurality of microlenses in the lens array group. After the de-spacing processing, the shapes of the plurality of microlenses are basically different from each other, and the plurality of microlenses with basically different shapes are closely arranged in a staggered manner on the surface of the light homogenizing layer to form a continuous surface.

[0056] Further, the shapes of the plurality of microlenses after the de-spacing processing include one or more combinations of a triangle, a quadrilateral, a pentagon, and a hexagon.

[0057] A further aspect, the present invention also provides a TOF lens, which includes the above-mentioned micro-microlens array light homogenizing structure. The micro-microlens array light homogenizing structure has a lens array group, and an air layer with a thickness range of 0.1 mm to 0.5 mm is provided between the lens array group and the laser array light source.

[0058] In yet another aspect, the present invention also provides a device equipped with a TOF lens, which includes the above-mentioned TOF lens, and the above-mentioned micro-microlens array light homogenizing structure is mounted on the TOF lens.

[0059] Compared with the prior art, the present invention has one or more of the following beneficial effects:

[0060] 1. The micro-uniform beam structure of the present invention is composed of a microlens array. By arranging them at intervals, microlenses with different radii of curvature and different shapes are formed. This uniform beam structure can be composed of microlenses with different apertures and different shapes, thereby disrupting the periodicity of the microlens array and eliminating interference phenomena after the laser array passes through the uniform beam structure of the microlens array.

[0061] 2. The fill rate of the uniform light structure microlens described in this invention can reach 100%. The larger fill rate can increase the utilization efficiency of incident light. There are no breaks between microlenses, so the transition between microlenses is continuous. The shape of a single microlens is similar to the desired light spot shape, which improves the uniformity of the light spot. From a processing perspective, the absence of breaks between microlenses also reduces the processing difficulty of nanoimprinting.

[0062] 3. The present invention ensures the aperture shape of the microlenses by arranging them at intervals, so that the aperture shape of the microlenses is similar to the desired light spot shape, and the laser array forms a uniform light spot of the required shape after passing through the uniform light structure, so that the obtained light spot is almost identical to the target light spot.

[0063] 4. In the interleaved arrangement proposed in this invention, the radius of curvature of each microlens is random, but the arrangement of the microlens centers and the radius of curvature of each microlens follow the interleaved arrangement method. Through this arrangement method, the boundary definition between microlenses is clear, easy to design, and easy to perform grayscale compensation when making photolithography master.

[0064] 5. This invention controls the shape of the light spot formed by the laser array after passing through the microlens array by arranging the laser array at intervals, and experiments have shown that it can achieve a field of view of 70° and above;

[0065] 6. The microlens array structure proposed in this invention has a thickness of less than 0.6 mm and a light transmission size of less than 0.9 mm * 0.9 mm. The shape of the light spot formed is independent of the shape of the light transmission aperture of the microlens array, making it suitable for miniaturized TOF models.

[0066] 7. The microlens array uniform light structure described in this invention can be applied to TOF lenses to eliminate interference phenomena after the laser array passes through the lens array group, and maintain good uniformity of the light field. The microlens array structure has a 100% fill rate, which maximizes the utilization of incident light. The transition between microlenses is smooth, which improves the uniformity of the light field and reduces the processing difficulty of imprinting. Attached Figure Description

[0067] 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.

[0068] Figure 1-1 This is a three-dimensional rendering of the concave microlens array structure described in Example 1;

[0069] Figure 1-2 This is a front view of the concave microlens array structure described in Example 1;

[0070] Figure 1-3 This is a side view of the concave microlens array structure described in Example 1;

[0071] Figure 1-4 This is a schematic diagram of the far-field emitted light field distribution of the microlens array described in Example 1;

[0072] Figure 1-5 This is a schematic diagram of the overall uniform light structure described in Example 1;

[0073] Figure 2-1 This is a three-dimensional rendering of the concave microlens array structure described in Example 2;

[0074] Figure 2-2 This is a front view of the concave microlens array structure described in Example 2;

[0075] Figure 2-3 This is a side view of the concave microlens array structure described in Example 2;

[0076] Figure 2-4 This is a schematic diagram of the far-field emitted light field distribution of the microlens array described in Example 2;

[0077] Figure 2-5 This is a schematic diagram of the overall uniform light structure described in Example 2;

[0078] Figure 3-1 This is a three-dimensional rendering of the concave microlens array structure described in Example 3;

[0079] Figure 3-2 This is a front view of the concave microlens array structure described in Example 3;

[0080] Figure 3-3 This is a side view of the concave microlens array structure described in Example 3;

[0081] Figure 3-4 This is a schematic diagram of the far-field emitted light field distribution of the microlens array described in Example 3;

[0082] Figure 3-5 This is a schematic diagram of the overall uniform light structure described in Example 3;

[0083] Figure 4-1 This is a three-dimensional rendering of the concave microlens array structure described in Example 4;

[0084] Figure 4-2 This is a front view of the concave microlens array structure described in Example 4;

[0085] Figure 4-3 This is a side view of the concave microlens array structure described in Example 4;

[0086] Figure 4-4 This is a schematic diagram of the far-field emitted light field distribution of the microlens array described in Example 4;

[0087] Figure 4-5 This is a schematic diagram of the overall uniform light structure described in Example 4.

[0088] Figure 5 This is a schematic diagram of the microlens array light-uniforming structure described in one embodiment of the present invention;

[0089] Figure 6 This is a schematic diagram of the fabrication process of the microlens array homogenizing structure described in Example 5;

[0090] Figure 7 This is a schematic diagram of the fabrication process of the microlens array homogenizing structure described in Example 6;

[0091] Figure 8 This is a schematic diagram of the fabrication process of the microlens array homogenizing structure described in Example 7. Detailed Implementation

[0092] The technical solutions of the embodiments of the present invention will be thoroughly reviewed and described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0093] Example:

[0094] The essence of the present invention will be further explained below with reference to the accompanying drawings and embodiments.

[0095] Please see Figure 5 Among them, 01-base layer, 02-light homogenizing layer, 03-lens array group.

[0096] A light homogenizing structure of a micro microlens array according to the present invention includes a base layer 01 and a light homogenizing layer 02 formed on the surface of the base layer 01. A lens array group 03 is formed on the surface of the light homogenizing layer 02 facing away from the base layer 01. This is the basic structural feature of the light homogenizing structure described in the present invention.

[0097] In one embodiment, the lens array group 03 is composed of a plurality of microlenses. The curvature radii and shapes of the plurality of microlenses are all different. The plurality of microlenses are arranged in a staggered manner to form the lens array group 03. The lens array group 03 forms a continuous surface on the surface of the light homogenizing layer 02. It can form a single continuous surface or multiple discontinuous surfaces. Although covering the light homogenizing layer 02 with these multiple discontinuous surfaces can also achieve certain optical effects, the optical effects are not as good as those brought by the lens array group 03 that can completely cover the light homogenizing layer 02. For a well-made light homogenizing structure, the filling rate of the lens array group 03 on the light homogenizing layer 02 can reach 100%.

[0098] The lens array group described in the present invention can be obtained by combining the following structural features:

[0099] The plurality of microlenses are arranged at intervals to form a matrix. The adjacent two columns of the matrix form an interval group. The two columns forming this interval group can be respectively called an interval. An interval (i.e., a column) includes a plurality of microlenses. The curvature radii of the microlenses in one column (i.e., an interval in an interval group) of the adjacent two columns are arranged according to the rule of gradually increasing from the middle to both ends. The curvature radii of the microlenses in the other column (i.e., the other interval in an interval group) of the adjacent two columns are arranged according to the rule of gradually decreasing from the middle to both ends.

[0100] If the number of microlenses in one column of the adjacent two columns is N and the number of microlenses in the other column of the adjacent two columns is M,

[0101] then, when N>M, the lens curvature radius of the column with M microlenses is greater than the lens curvature radius of the column with N microlenses;

[0102] when N<M, the lens curvature radius of the column with M microlenses is less than the lens curvature radius of the column with N microlenses;

[0103] Among them, the values of M and N include integers within 2 to 10, and the values of M and N are adjacent integers. For example, M takes 4, N takes 5, M takes 2, N takes 3, M takes 7, N takes 8, etc.

[0104] It should be noted here that the "column" mentioned in the text should not be understood as a limitation to the present invention. Those skilled in the art can also understand or regard this as the corresponding "row" in actual applications.

[0105] The plurality of microlenses are arranged in a matrix at intervals. Two adjacent columns of the matrix form an interval group, and the two columns that make up this interval group can be referred to as an interval. Within an interval, the range of values ​​of the radius of curvature of the microlenses determines the number of microlenses in that interval. The larger the range of values ​​of the radius of curvature of the microlenses, the more microlenses are in that interval.

[0106] In one embodiment, the lens array group 03 has several columns, and the center-to-center distance between two adjacent microlenses in any column is 25μm-120μm.

[0107] In one embodiment, the substrate 01 may be a light-transmitting glass substrate, the refractive index of the substrate 01 is greater than or equal to 1.4, and the transmittance of the substrate 01 for light in the 930nm-940nm wavelength band is greater than or equal to 90%.

[0108] The light-diffusing layer 02 is a molding adhesive layer, which is adhered to the light-transmitting glass substrate. The molding adhesive layer includes photoresist and / or imprinting adhesive, and preferably it is also a transparent layer.

[0109] The thickness of the light-transmitting glass substrate ranges from 0.3mm to 0.6mm, and the thickness of the molding adhesive layer ranges from 0.03mm to 0.1mm. These dimensional and structural features reduce the overall size of the uniform light structure and enhance its applicability.

[0110] In one embodiment, the microlenses comprising the lens array group 03 are all aspherical microlenses, and the radius of curvature of the aspherical microlenses ranges from 5μm to 300μm. Within a certain interval group, the radius of curvature of the microlens array group 03 is randomly selected.

[0111] When the uniform light structure of the present invention is applied, an air layer with a thickness ranging from 0.1 mm to 0.5 mm is provided between the lens array group 03 and the laser array light source.

[0112] A plurality of microlenses with different radii of curvature and shapes are arranged to form the lens array group 03. The microlenses within the lens array group 03 undergo a de-spacing process, forming a continuous surface. The microlenses fill 100% of the surface of the homogenizing layer 02. After the de-spacing process, the shapes of the microlenses constituting the lens array group 03 are all different, including triangles, quadrilaterals, pentagons, hexagons, or combinations of multiple shapes. The shapes of the microlenses after the de-spacing process are random, and various shapes are possible. These different shapes are designed to meet the optical characteristics required by the overall homogenizing structure; therefore, it can be said that the shapes of the microlenses after the de-spacing process can be arbitrary polygons.

[0113] In one embodiment, the distance between the two interval groups described in this invention is determined by the target light spot and the maximum and minimum radii of curvature of the microlenses in each interval group. The radii of curvature of the microlenses comprising an interval group are all different, and there are no microlenses with the same radii of curvature between interval groups. Therefore, no two microlenses with identical shapes and radii of curvature exist in the entire lens array. Of course, the microlens array uniform light structure described in this invention belongs to the micro / nano structure category. During the manufacturing process, multiple microlenses with the same shape may appear. For example, in one case, after de-segmentation, the shape of each microlens may be an arbitrary, irregular polygon, and these completely different microlenses can form a continuous surface. It is also possible that several microlenses with the same shape may accidentally appear after de-segmentation.

[0114] In one embodiment, within a spacing group, the distance between the centers of the microlenses is determined by the radius of curvature of the two corresponding microlenses and the desired shape of the light spot.

[0115] The larger the radius of curvature, the greater the distance between the centers of the microlenses, and the longer the length of the light spot shape along the line connecting the centers of two adjacent microlenses. If the radius of curvature is fixed, and it is required that the length of the light spot shape along the line connecting the centers of two adjacent microlenses be as long as possible, then the distance between the centers of the microlenses will be greater.

[0116] Example 1:

[0117] This invention proposes a microlens array light-uniforming structure; please refer to [link / reference]. Figures 1-1 to 1-5 , where 10 is a laser array light source; 11 is a lens array group.

[0118] In this embodiment, the laser array light source 10 illuminates the microlens array homogenizing structure (the surface of the lens array group 11 faces the light source) and then exits through the substrate layer, such as... Figure 1-5 As shown, the distance between the laser array light source 10 and the lens array group 11 is 0.3 mm, with air as the intermediate medium. The lens array group 11 has a concave single-layer structure, and the thickness of the base layer and the homogenizing layer (on which the lens array group 11 is adhered) is 0.5 mm. The microlenses in the lens array group 11 are arranged according to an interval arrangement method, and the center of each microlens is determined by this interval arrangement method. In this embodiment, the number of microlenses M in one row of the lens array group 11 is 5, and the number of microlenses N in the other row is 4. See also Figure 1-2 , Figure 1-2 The rightmost column has 10 microlenses, and the second-to-last column from the right has 8 microlenses. Based on the location of the center point of the radius of curvature of the microlenses in the diagram, we can start from the middle of the rightmost column (or the middle of the leftmost column) to... Figure 1-2 The lens array is divided into upper and lower parts. Counting from the rightmost column of the microlenses, the number of lenses in a single interval within the upper half of the lens array is 5, 4; 5, 4; 5, 4; 5, 4. Correspondingly, the number of lenses in a single interval within the lower half of the lens array is also 5, 4; 5, 4; 5, 4; 5, 4 (counting from the rightmost column to the leftmost column).

[0119] In this embodiment, the lateral length of the microlens is between 75 micrometers and 115 micrometers, and the longitudinal length is between 61 micrometers and 94 micrometers. The radius of curvature and the conic coefficient of the microlens change accordingly with the size of the microlens, and the radius of curvature varies from 24 micrometers to 54 micrometers.

[0120] In this embodiment, the height of the connection between adjacent microlenses is the same, there is no break at the connection, and the fill rate is 100%.

[0121] In this embodiment, each microlens in the lens array group 11 is a quadrilateral, pentagon, hexagon or other polygon. Each microlens has a different shape and a different radius of curvature, and they are kept closely arranged. Moreover, the shape of these microlenses is random, and various shapes are possible. The various shapes of the microlenses are all to adapt to the optical characteristics required by the overall uniform light structure.

[0122] See Figure 1-4The image shows a light spot formed at a distance of 250mm from the uniform light structure. Based on tan(θ / 2) = h / L, where h is the half-height of the light spot and L is the distance from the uniform light structure, the energy ratio at each field of view relative to the zero-degree field of view is obtained. In this embodiment, the concave microlens array achieves a horizontal field of view greater than 70 degrees and a vertical field of view greater than 60 degrees. The scattered energy at the horizontal field of view peaks at 60 degrees, and the light intensity drops to 80% of the center intensity at 68 degrees, making it suitable for TOF modules in portable devices and facilitating algorithmic recognition. The scattered energy at the vertical field of view peaks at 50 degrees.

[0123] Example 2:

[0124] This invention proposes a microlens array light-uniforming structure; please refer to [link / reference]. Figures 2-1 to 2-5 , where 20 is the laser array light source; 21 is the lens array group.

[0125] In this embodiment, the laser array light source 20 illuminates the micro-microlens array homogenizing structure (the surface of the lens array group 21 faces the light source) and then exits through the substrate layer, such as... Figure 2-5 As shown, the distance between the laser array light source 20 and the lens array group 21 is 0.2 mm, with air as the intermediate medium. The lens array group 21 has a concave single-layer structure, and the total thickness of the base layer and the homogenizing layer is 0.5 mm. The microlenses in the lens array group 21 are arranged according to an interval arrangement method, and the center of the microlens is determined by the interval arrangement method. In this embodiment, the number M of microlenses in one row of the lens array group 21 is 5, and the number N of microlenses in the other row is 4. Similarly, the method for determining the number of microlenses is the same as... Figure 1-2 The determination method is the same as that used in the previous section, so it will not be repeated here.

[0126] In this embodiment, the lateral length of the microlens is between 30 and 70 micrometers, and the longitudinal length is between 24.5 and 58 micrometers. The radius of curvature of the microlens and the conic coefficient change accordingly with the size of the microlens, and the radius of curvature varies from 8 to 18 micrometers.

[0127] In this embodiment, the height of the connection between adjacent microlenses is the same, there is no break at the connection, and the fill rate is 100%.

[0128] In this embodiment, each microlens in the lens array group 21 is a quadrilateral, pentagon, hexagon or other polygon. Each microlens has a different shape and a different radius of curvature, and they are kept closely arranged. Moreover, the shape of these microlenses is random, and various shapes are possible. The various shapes of the microlenses are all to adapt to the optical characteristics required by the overall uniform light structure.

[0129] See Figure 2-4By altering the number of microlenses in each interval and the distance between them, and considering a group of microlenses with identical surface shapes, the ratio of the vertical and horizontal distances between different microlenses determines the magnitude and ratio of the vertical and horizontal field of view of the emitted light. In this embodiment, the concave microlens array achieves a horizontal field of view greater than 70 degrees and a vertical field of view greater than 60 degrees. The scattering energy at the horizontal field of view peaks at 60 degrees, while the scattering energy at the vertical field of view peaks at 50 degrees.

[0130] Example 3:

[0131] This invention proposes a microlens array light-uniforming structure; please refer to [link / reference]. Figures 3-1 to 3-5 Among them, 30 is a laser array light source; 31 is a lens array group.

[0132] In this embodiment, the laser array light source 30 illuminates the microlens array homogenizing structure (the surface of the lens array group 31 faces the light source) and then exits through the substrate layer, such as... Figure 3-5 As shown, the distance between the laser array light source 30 and the lens array group 31 is 0.3 mm, with air as the intermediate medium. The lens array group 31 is a concave single-layer structure with a thickness of 0.5 mm. The microlenses in the lens array group 31 are arranged according to an interval arrangement method. The center of each microlens is determined by the interval arrangement method. In this embodiment, the number of microlenses M in one row of the lens array group 31 is 3, and the number of microlenses N in the other row is 2. Similarly, the method for determining the number of microlenses is the same as... Figure 1-2 The determination method is the same as that used in the previous section, so it will not be repeated here.

[0133] In this embodiment, the lateral length of the microlens is between 70 micrometers and 120 micrometers, and the longitudinal length is between 45 micrometers and 80 micrometers. The radius of curvature of the microlens and the conic coefficient change accordingly with the size of the microlens, and the radius of curvature varies from 25 micrometers to 40 micrometers.

[0134] In this embodiment, the height of the connection between adjacent microlenses is the same, there is no break at the connection, and the fill rate is 100%.

[0135] In this embodiment, each microlens in the lens array group 31 is a quadrilateral, pentagon, hexagon, or other polygon. Each microlens has a different shape and a different radius of curvature, and they are kept closely arranged. The shapes of these microlenses are random, and various shapes are possible. The various shapes of the microlenses are all to adapt to the optical characteristics required by the overall uniform light structure.

[0136] In this embodiment, the horizontal field of view of the concave microlens array is greater than 70 degrees and the vertical field of view is greater than 50 degrees. The scattering energy of the horizontal field of view reaches its peak at 58 degrees and the scattering energy of the vertical field of view reaches its peak at 40 degrees.

[0137] Example 4:

[0138] This invention proposes a microlens array light-uniforming structure; please refer to [link / reference]. Figures 4-1 to 4-5 , where 40 is the laser array light source; 41 is the lens array group.

[0139] In this embodiment, the laser array light source 40 illuminates the micro-lens array homogenizing structure (the surface of the lens array group 41 faces the light source) and then exits through the substrate layer, such as... Figure 4-5 As shown, the distance between the laser array light source 40 and the lens array group 41 is 0.3 mm, with air as the intermediate medium. The lens array group 41 is a concave single-layer structure with a thickness of 0.5 mm. The microlenses in the lens array group 41 are arranged according to an interval arrangement method. The center of each microlens is determined by the interval arrangement method. In this embodiment, the number of microlenses M in one row of the lens array group 41 is 3, and the number of microlenses N in the other row is 2. Similarly, the method for determining the number of microlenses is the same as... Figure 1-2 The determination method is the same as that used in the previous section, so it will not be repeated here.

[0140] In this embodiment, the lateral length of the microlens is between 30 micrometers and 50 micrometers, and the longitudinal length is between 20 micrometers and 34 micrometers. The radius of curvature of the microlens and the conic coefficient change accordingly with the size of the microlens, and the radius of curvature varies from 8 micrometers to 20 micrometers.

[0141] In this embodiment, the height of the connection between adjacent microlenses is the same, there is no break at the connection, and the fill rate is 100%.

[0142] In this embodiment, each microlens in the lens array group 41 is a quadrilateral, pentagon, hexagon, or other polygon. Each microlens has a different shape and a different radius of curvature, and they are kept closely arranged. The shape of these microlenses is random, and various shapes are possible. The various shapes of the microlenses are all to adapt to the optical characteristics required by the overall uniform light structure.

[0143] In this embodiment, the concave microlens array is expected to achieve a horizontal field of view greater than 70 degrees and a vertical field of view greater than 50 degrees. The scattering energy of the horizontal field of view reaches its peak at 58 degrees, and the scattering energy of the vertical field of view reaches its peak at 40 degrees.

[0144] Based on embodiments 1 to 4, this invention proposes a microlens array homogenizing structure. By arranging microlenses with different radii of curvature and shapes at intervals, this homogenizing structure is composed of microlenses with different apertures and shapes, thereby disrupting the periodicity of the microlens array and eliminating interference phenomena after the laser array passes through the microlens array homogenizing structure.

[0145] The uniform light structure microlens described in this invention has a 100% fill rate, which increases the utilization efficiency of incident light. There are no breaks between microlenses, and the transition between microlenses is continuous. The shape of a single microlens is similar to the desired light spot shape, which improves the uniformity of the light spot. Furthermore, there are no breaks between microlenses, which reduces the processing difficulty of nanoimprinting.

[0146] The spacing arrangement proposed in this invention involves random curvature radii for each microlens, but the arrangement of the microlens centers and the curvature radii of each microlens follow the spacing arrangement method. This arrangement method makes the boundary definition between microlenses clear, easy to design, and easy to perform grayscale compensation when making photolithography master.

[0147] This invention controls the shape of the light spot formed by the laser array after passing through the microlens array by arranging the laser array at intervals. Experiments have shown that it can achieve a field of view of 70° or more.

[0148] The microlens array structure proposed in this invention has a thickness of less than 0.6 mm and a light transmission size of less than 0.9 mm * 0.9 mm. The shape of the light spot formed is independent of the shape of the light transmission aperture of the microlens array, making it suitable for miniaturized TOF models.

[0149] In conjunction with Examples 1-4, compare Figure 1-4 , 2-4 Figures 3-4 and 4-4 verify that the microlens surface shape, the distance between microlenses, and the distance between microlenses in the vertical and horizontal directions all affect the properties of the formed light spot. When the microlens surface shapes in the two intervals of this invention are the same (each interval is composed of microlenses with different surface shapes), the larger the distance between the two intervals, the longer the light spot is in the direction of that distance; when the distance between microlenses is the same, the greater the surface curvature, the larger the overall size of the light spot; when the microlens distance is the same, the greater the conicity of the surface shape, the narrower the peak value of the light spot, and the stronger the energy at the peak value.

[0150] The arrangement method described in this invention changes the ratio of the vertical to the horizontal direction of a certain column of microlenses. In the same interval group of this invention, the aspect ratio of the light spot is changed by changing the ratio of the length of the line connecting the centers of two vertically adjacent microlenses to the length of the line connecting the centers of two horizontally adjacent microlenses.

[0151] Figure 1-4 Light spot and Figure 2-4 The light spots are basically the same because their spacing arrangement has M = 4 and N = 5. Figure 3-4 Light spot and Figure 4-4 The light spots are basically the same because M is 2 and N is 3 in their spacing arrangement. The arrangement, the values ​​of M and N in the spacing, the curvature of the microlenses, the conic coefficient, the spacing between the microlenses, the length of the line connecting the centers of two horizontally adjacent microlenses, and the length of the line connecting the centers of two vertically adjacent microlenses determine the shape and size of the light spots, as well as the position and width of the bright ring.

[0152] This invention also proposes a method for fabricating a microlens array homogenizing structure, which is illustrated in the figures of Examples 5-6. Figure 6 The method for fabricating the uniform light structure includes:

[0153] A substrate layer 53 is provided, wherein the substrate layer 53 is a light-transmitting glass sheet;

[0154] A pattern forming template 51 is provided, and a first pattern structure is formed on the surface of the pattern forming template 51. The first pattern structure is opposite to the structure of the micro-microlens array pattern, and the first pattern structure is referred to as the reverse micro-microlens pattern 52.

[0155] A molding adhesive, also known as an imprinting adhesive, is provided. The pattern forming template 51 is used as a mold, and the molding adhesive is formed onto the base layer 53 by imprinting. The micro-microlens array pattern is formed on the surface of the base layer 53 to obtain a micro-microlens array uniform light structure.

[0156] The microlens array pattern comprises several microlenses arranged without spacing.

[0157] The refractive index of the molding compound is greater than or equal to 1.4.

[0158] In one embodiment, see Figure 7 The method for manufacturing the pattern forming template of the present invention specifically includes:

[0159] A pattern forming layer 61 is provided, and a second pattern structure is formed on the surface of the pattern forming layer 61. The second pattern structure is consistent with the micro-microlens array pattern structure. The second pattern structure is referred to as the forward micro-microlens pattern 63.

[0160] A pattern transfer layer 64 is provided, and the pattern forming layer 61 is used as a template. Plastic is molded onto the pattern transfer layer 64 by pressing, and a first pattern structure, namely a reverse micro-microlens pattern 52, which is opposite to the micro-microlens array pattern structure is formed on the surface of the pattern transfer layer 64, thus obtaining the pattern forming template 69.

[0161] The molding compound is made of resin.

[0162] In one embodiment, the present invention uses diamond turning technology to turn and form a first pattern structure, namely a reverse micro-microlens pattern 52, to obtain the pattern forming template 69.

[0163] The pattern forming template is a metal template.

[0164] In one embodiment, the present invention forms a second pattern structure, namely a positive microlens pattern 63, on the surface of the pattern forming layer 61 by diamond turning technology.

[0165] In one embodiment, the present invention forms a second pattern structure on the surface of the pattern forming layer 61, specifically including:

[0166] Photoresist is uniformly spin-coated onto the surface of the pattern forming layer to form a photoresist layer 62, the thickness of which is 5μm-50μm.

[0167] The photoresist layer 62 is exposed to multiple times at different gray levels and gray level compensation is performed to form the second pattern structure, namely the positive microlens pattern 63, on the surface of the pattern forming layer 61.

[0168] In one embodiment, see Figure 8 The present invention forms a second pattern structure on the surface of the pattern forming layer 71, specifically including:

[0169] The pattern forming layer 71 is immersed in the photosensitive resin 72, and the photosensitive resin 72 is exposed to different gray levels multiple times to form the second pattern structure, namely the positive microlens pattern 63, on the surface of the pattern forming layer 71.

[0170] In one embodiment, the thickness of the substrate layer 76 of the present invention ranges from 0.3 mm to 0.6 mm.

[0171] The refractive index of the substrate 76 is greater than or equal to 1.4, and the transmittance of the substrate 76 for light in the 930nm-940nm wavelength band is greater than or equal to 90%.

[0172] Example 5:

[0173] This invention also proposes a method for fabricating a microlens array homogenizing structure; please refer to [link to relevant documentation]. Figure 6 Among them, 51-pattern forming template; 52-reverse microlens pattern (i.e., first pattern structure); 53-base layer; 54-forward microlens pattern (i.e., second pattern structure).

[0174] In this embodiment, the manufacturing method includes:

[0175] A pattern forming template 51 is provided, and a reverse microlens pattern 52 is formed on the surface of the pattern forming template 51.

[0176] In one embodiment, a reverse microlens pattern 52 is formed on the surface of the pattern forming template 51 by diamond turning.

[0177] A substrate layer 53 is provided, and a pattern forming template 51 with the reverse microlens pattern 52 formed on its surface is formed on the substrate layer 53 by pressing to form the forward microlens pattern 54.

[0178] In one embodiment, the pattern forming template 51 is used as a mold, and the resin material is hot-pressed onto the base layer 53 by molding to form the designed microlens array structure, thereby obtaining the positive microlens pattern 54.

[0179] Example 6:

[0180] This invention also proposes a method for fabricating a microlens array homogenizing structure; please refer to [link to relevant documentation]. Figure 7 Among them, 61-patterning layer; 62-photoresist layer; 63-forward microlens pattern; 64-pattern transfer layer; 65-reverse microlens pattern (i.e., first pattern structure); 66-substrate layer; 67-forward microlens pattern (i.e., second pattern structure); 68-microlens array uniform light structure; 69-pattern forming template.

[0181] In this embodiment, the manufacturing method includes:

[0182] A patterning layer 61 is provided, on which a positive microlens pattern 63 is formed.

[0183] In one embodiment, photoresist is uniformly spin-coated onto the pattern forming layer 61 to form a photoresist layer 62 with a thickness of 5μm-50μm. The photoresist layer 62 is then photolithographically etched using a grayscale exposure method to form a forward microlens pattern 63 on its surface. By exposing the photoresist layer 62 to different grayscale levels multiple times and performing grayscale compensation, the fabrication accuracy of the microlens array can be improved.

[0184] A pattern transfer layer 64 is provided, and a reverse microlens pattern 65 is formed on the pattern transfer layer 64 by imprinting the pattern forming layer 61 on which the forward microlens pattern 63 is formed.

[0185] In one embodiment, a forward microlens pattern 63 on the surface of the pattern forming layer 61 is nanoimprinted to form a reverse microlens pattern 65 on the surface of the pattern transfer layer 64.

[0186] A substrate 66 is provided, and a pattern transfer layer 64, on which the reverse microlens pattern 65 is formed, is formed by imprinting the forward microlens pattern 67 onto the substrate 66.

[0187] In one embodiment, a reverse microlens pattern 65 on the surface of the pattern transfer layer 64 is nanoimprinted to form a forward microlens pattern 67 on the surface of the substrate layer 66, thereby obtaining a microlens array uniform light structure 68.

[0188] Example 7:

[0189] This invention also proposes a method for fabricating a microlens array homogenizing structure; please refer to [link to relevant documentation]. Figure 8 Among them, 71-pattern forming layer; 72-photosensitive resin; 73-forward microlens pattern (i.e., second pattern structure); 74-pattern transfer layer; 75-reverse microlens pattern (i.e., first pattern structure); 76-substrate layer; 77-forward microlens pattern (i.e., second pattern structure); 78-microlens array uniform light structure.

[0190] In this embodiment, the manufacturing method includes:

[0191] A patterning layer 71 is provided, on which a positive microlens pattern 73 is formed.

[0192] In one embodiment, the pattern forming layer 71 is immersed in a photosensitive resin 72, and the positive microlens pattern 73 is formed on the surface of the pattern forming layer 71 by exposing the photosensitive resin 72 to multiple exposures at different gray levels. By exposing the photosensitive resin 72 to different gray levels using a gray-scale exposure method, and by performing multiple exposures and gray-scale compensation, the fabrication accuracy of the microlens array can be improved.

[0193] A pattern transfer layer 74 is provided, and a reverse microlens pattern 75 is formed on the pattern transfer layer 74 by imprinting the pattern forming layer 71 on which the forward microlens pattern 73 is formed;

[0194] In one embodiment, a forward microlens pattern 73 on the surface of the pattern forming layer 71 is nanoimprinted to form a reverse microlens pattern 75 on the surface of the pattern transfer layer 74.

[0195] A substrate layer 76 is provided, and a pattern transfer layer 74, on which the reverse microlens pattern 75 is formed, is formed by imprinting the forward microlens pattern 77 onto the substrate layer 76.

[0196] In one embodiment, the reverse micro-microlens pattern 75 on the surface of the pattern transfer layer 74 is nanoimprinted to form a forward micro-microlens pattern 77 on the surface of the substrate layer 76, thereby obtaining a micro-microlens array uniform light structure 78.

[0197] Based on embodiments 5-7, the micro-microlens array light-uniformation structure of the present invention, which is suitable for small TOF lens modules, can reduce the thickness and size of the light-uniformation structure, meet the needs of miniaturized devices such as mobile phones and tablets for small light-uniformation devices. Compared with regular microlens arrays, the shape and curvature of the microlens array based on the interval arrangement method meet the random distribution, which can eliminate the interference phenomenon formed after passing through the microlens array.

[0198] The manufacturing method described in this invention can process the pattern forming layer of the microlens array using diamond turning technology, photosensitive resin curing technology, grayscale photolithography technology, etc., and manufacture the microlens array by nanoimprinting, so that the thickness of the microlens array is maintained at 0.3mm to 0.5mm, and there are no breaks between the microlenses, which reduces the processing difficulty of nanoimprinting and improves the processing accuracy.

[0199] The microlens uniform light structure of the present invention has irregular aperture shapes for each microlens, and the radius of curvature, center point, etc. are randomly arranged by an interval arrangement method. The boundaries between microlenses are clearly defined, which is easy to design. The transition between microlenses is continuous, which improves the uniformity of the emitted light field. When using photolithography to process the master plate, it is easy to perform grayscale compensation.

[0200] The microlens array uniform light structure described in this invention can be applied to small-scale TOF to eliminate interference phenomena after the laser array passes through the uniform light array and maintain good uniformity of the light field. The microlens array structure has a 100% fill rate, maximizing the utilization of incident light. The transition between microlenses is smooth, improving the uniformity of the light field and reducing the processing difficulty of imprinting.

[0201] In one embodiment, the present invention also provides a TOF lens, which includes the above-described microlens array homogenizing structure.

[0202] In one embodiment, the present invention also provides a device equipped with a TOF lens, which includes a TOF lens on which the above-described microlens array homogenizing structure is mounted.

[0203] In one embodiment, the design method of the micro microlens array pattern of the present invention may specifically include:

[0204] Arrange several microlenses in multiple adjacent groups. Two adjacent groups form a spacing group. The radius of curvature of the microlenses in one of the two adjacent groups is arranged according to the rule of gradually increasing from the middle to both ends, and the radius of curvature of the microlenses in the other group of the two adjacent groups is arranged according to the rule of gradually decreasing from the middle to both ends;

[0205] If the number of microlenses in one of the two adjacent groups is N, and the number of microlenses in the other group of the two adjacent groups is M,

[0206] then, when N>M, the radius of curvature of the lenses in the group with M microlenses is greater than the radius of curvature of the lenses in the group with N microlenses;

[0207] when N<M, the radius of curvature of the lenses in the group with M microlenses is less than the radius of curvature of the lenses in the group with N microlenses;

[0208] wherein, the values of M and N include integers within 2 to 10 and are adjacent integers. For example, M takes 4, N takes 5, M takes 2, N takes 3, M takes 7, N takes 8, etc.

[0209] Further, the lens array group includes several of the spacing groups, and several of the spacing groups form a lens array group. The center-to-center distance between two adjacent microlenses within one spacing group is 25μm - 120μm,

[0210] The several microlenses are arranged in a matrix through gap arrangement, and the connection line of the centers of any column of microlenses in the matrix forms a straight line.

[0211] Perform a de-spacing process on the several microlenses arranged in a matrix through gap arrangement. After the de-spacing process, the shapes of the several microlenses are basically different from each other, and the several microlenses with basically different shapes are closely arranged in a staggered manner on the surface of the light homogenizing layer to form a continuous surface.

[0212] Further, the shapes of the several microlenses after the de-spacing process can be any polygon; the de-spacing process is to perform a union process on multiple groups of microlenses so that each microlens is seamlessly connected. After selecting a starting point, the remaining microlenses can be arranged in sequence so that all microlenses form a continuous surface. Therefore, the shapes of the several microlenses after the de-spacing process are only to satisfy the formation of a continuous surface by all microlenses, and it can be said that the shapes of the several microlenses after the de-spacing process can be any polygon.

[0213] In one embodiment, the specific spacing arrangement method of the present invention may include:

[0214] The center position of the microlenses is determined by a spacing method, with different microlens radii of curvature determining different center positions. Each group of spaced microlenses is divided into two rows. The radius of curvature of one row of microlenses is largest in the middle and decreases towards the sides, while the radius of curvature of the other row is smallest in the middle and increases towards the sides. The centers of each row of microlenses lie on a straight line, and the spacing between the centers of each row is unequal. The spacing of the microlenses is determined by their radius of curvature and the desired shape of the light spot. The radius of curvature of each microlens is random, ranging from 5μm to 300μm. The center position of each microlens is determined by its respective radius of curvature and the desired shape of the light spot.

[0215] More specifically, the lens array group described in this invention is formed into a matrix by arranging the array in an interval manner, with a certain radius of curvature interval (assumed to be the first radius of curvature interval) and another radius of curvature interval (assumed to be the second radius of curvature interval) forming an interval.

[0216] N radii of curvature are randomly selected from the first curvature radius interval, and the microlens curvature radii are arranged in a pattern that gradually increases from the middle to both ends. M radii of curvature are randomly selected from the second curvature radius interval, and the microlens curvature radii are arranged in a pattern that gradually decreases from the middle to both ends. These two arrangements form an interval. Correspondingly, in the next interval, N radii of curvature are randomly selected from the first curvature radius interval. If M is greater than N, the curvature radii selected in the M arrangement are smaller than those selected in the N arrangement; if N is greater than M, the curvature radii selected in the M arrangement are greater than those selected in the N arrangement. The microlens curvature radii are arranged in a pattern that gradually increases from the middle to both ends. M radii of curvature are randomly selected from the second curvature radius interval. These M radii of curvature are different from those selected in the first interval, and the microlens curvature radii are arranged in a pattern that gradually decreases from the middle to both ends. The distance between the two intervals is determined by the desired shape of the light spot and the maximum and minimum curvature radii of curvature of the microlenses selected in each interval.

[0217] In the aforementioned interval arrangement method, when arranging a single interval, the distance between the centers of the microlenses is determined by the radius of curvature selected for the corresponding two microlenses and the desired shape of the light spot. The larger the radius of curvature, the larger the distance between the centers of the microlenses, and the longer the length of the light spot shape in the direction of the line connecting the centers of the two adjacent microlenses. If the radius of curvature is fixed, and the length of the light spot shape in the direction of the line connecting the centers of the two adjacent microlenses is required to be as long as possible, then the distance between the centers of the two adjacent microlenses is larger.

[0218] Furthermore, when arranging individual intervals, regardless of how the centers of the microlenses are arranged according to the microlens curvature radius arrangement rule, the value of the microlens curvature radius within the interval is random, ranging from 5μm to 300μm.

[0219] Furthermore, this method is used to perform the third, fourth, and up to the nth interval. The distance between each two intervals is determined by the maximum and minimum radius of curvature of the microlens taken in the corresponding interval and the required shape of the light spot. Moreover, the radius of curvature of the microlens taken in each interval is different (the radius of curvature of the microlenses in the same group of intervals is different, and the radius of curvature of the microlenses in different intervals is different).

[0220] Furthermore, the range of values ​​for the radius of curvature of the microlenses within the same interval is specific. This range determines the number of microlenses that can be used in that interval. The larger the range of values ​​for the radius of curvature of the microlenses, the more microlenses can be used in the corresponding interval.

[0221] After arranging the microlens array using the aforementioned interval arrangement method, the radius of curvature of each microlens is different, and the radius of curvature is random within the range of 5μm to 300μm; moreover, the shape of each microlens is different, and the shape of each microlens can become a triangle, quadrilateral, pentagon, hexagon, heptagon, octagon or other polygon. The overall microlens array is composed of microlenses of various different shapes. This microlens structure can completely destroy the periodicity of the microlens array and eliminate the interference phenomenon generated after the uniform light structure passes through.

[0222] In this invention, the center-to-center spacing of the microlenses in the same interval is 25 micrometers to 120 micrometers, the radius of curvature of the microlenses is 5 micrometers to 300 micrometers, and the spacing between adjacent intervals is determined by the range of values ​​of the radius of curvature of the microlenses in the corresponding interval and the desired shape of the light spot.

[0223] The microlens array structure arranges each microlens in its corresponding position according to the spacing method. Each microlens has its own corresponding radius of curvature. After the arrangement is completed, the microlens array is de-spaced, which can also be called a union. Before the union, each microlens has a circular aperture and intersects with the surrounding microlenses. After the union, the shape of each microlens becomes a polygon, and there are no breaks at the connection between adjacent polygons. The filling rate can reach 100%, thereby increasing the utilization efficiency of incident light. The lack of breaks in the microlens array also reduces the processing difficulty of nanoimprinting.

[0224] In one embodiment, the thickness of the substrate layer 01 is 0.3mm-0.6mm, and the thickness of the homogenizing layer 02 is 0.03mm-0.1mm. This invention addresses the shortcomings of existing homogenizing devices, such as significant interference after light transmission and large size, which makes them unsuitable for miniaturized devices. It provides a small-volume microlens structure. This structure is suitable for miniaturized Time-of-Flight (TOF) models and can be applied to portable small electronic devices such as mobile phones and tablets. Furthermore, compared to traditional periodic microlens arrays, this structure effectively eliminates interference fringes generated after light transmission in homogenizing structures, improving the uniformity of the light spot on the illuminated surface.

[0225] This invention controls the shape of the light spot formed by the laser array after passing through the microlens array by arranging the laser array at intervals, and can achieve a field of view of 70° or more.

[0226] The present invention employs an intermittent arrangement, which eliminates the gaps between microlenses and ensures a continuous transition between them. The shape of each individual microlens is similar to the desired light spot shape, thereby improving the uniformity of the light spot.

[0227] In the interleaved arrangement proposed in this invention, the radius of curvature of each microlens is random, but the arrangement of the microlens centers and the radius of curvature of each microlens follow the interleaved arrangement method. Through this arrangement method, the boundary definition between microlenses is clear, easy to design, and easy to perform grayscale compensation when making photolithography master.

[0228] The lens array group 03 proposed in this invention has a thickness of less than 0.6 mm, a light-diffusing layer 02 (photoresist layer) thickness of less than 0.1 mm, and a light-transmitting size of less than 0.9 mm * 0.9 mm. The shape of the light spot formed is independent of the shape of the light-transmitting aperture formed by the microlens array, which meets the thickness requirements of light-diffusing devices for miniaturized equipment and is suitable for miniaturized TOF models.

[0229] The center spacing of the microlenses in the lens array group 03 of the present invention is determined by the radius of curvature of the corresponding two microlenses. Since the microlenses are aspherical structures, the surface shape of the microlenses should be determined by the radius of curvature and the aspherical coefficient. The center spacing of the microlenses, the radius of curvature of the microlenses, and the aspherical coefficient of the microlenses together determine the shape of the light spot and the light intensity distribution after the laser array passes through the microlens array structure.

[0230] 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.

[0231] 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 microlens array light-uniforming structure, characterized in that, It includes a base layer, and a light homogenizing layer formed on the surface of the base layer. A lens array group is formed on the surface of the light homogenizing layer facing away from the base layer. A plurality of microlenses are arranged out of alignment to form the lens array group, and the lens array group forms a continuous surface on the surface of the light homogenizing layer. The plurality of microlenses are arranged in multiple adjacent groups. Two adjacent columns form a spacing group. The radius of curvature of the microlenses in one column of the two adjacent columns is arranged according to the rule of gradually increasing from the middle to both ends, and the radius of curvature of the microlenses in the other column of the two adjacent columns is arranged according to the rule of gradually decreasing from the middle to both ends. If the number of microlenses in one column of the two adjacent columns is N, and the number of microlenses in the other column of the two adjacent columns is M. Then, when N > M, the lens radius of curvature of the column with M microlenses is greater than the lens radius of curvature of the column with N microlenses. When N < M, the lens radius of curvature of the column with M microlenses is less than the lens radius of curvature of the column with N microlenses. Wherein, the values of M and N include integers within 2 to 10, and the values of M and N are adjacent integers. The distance between the two spacing groups is determined by the spot shape formed by the target requirements, as well as the maximum and minimum radii of curvature of the microlenses in each spacing group.

2. The light homogenizing structure according to claim 1, wherein The base layer is a light-transmitting glass substrate, the refractive index of the base layer is greater than or equal to 1.4, and the light transmittance of the base layer for light in the wavelength range of 930 nm to 940 nm is greater than or equal to 90%. The light homogenizing layer is a plastic adhesive layer, and the plastic adhesive layer adheres to the light-transmitting glass substrate. The plastic adhesive layer includes photoresist and / or imprinting adhesive. The thickness range of the light-transmitting glass substrate is 0.3 mm - 0.6 mm, and the thickness of the plastic adhesive layer is 0.03 mm - 0.1 mm.

3. The light homogenizing structure according to claim 1, wherein A plurality of microlenses forming the lens array group are all microlenses with an aspherical surface type, and the range of the radius of curvature of the microlenses with an aspherical surface type is 5 μm - 300 μm. The shapes of a plurality of microlenses forming the lens array group are all different, and the shapes of the microlenses include one or more combinations of triangle, quadrilateral, pentagon, and hexagon.

4. The light homogenizing structure according to claim 1, wherein The lens array group has a plurality of columns, and the center-to-center distance between two adjacent microlenses on any one column of the plurality of columns is 25 μm - 120 μm. Within one spacing group, the value of the radius of curvature of the lens array group is random. Within one spacing group, the center-to-center distance between two adjacent microlenses is determined by the radii of curvature selected by the corresponding two microlenses and the spot shape required to be formed. The larger the selected radius of curvature of two corresponding micro - lenses, the larger the distance between the centers of two adjacent micro - lenses, and the longer the length of the light spot shape in the direction of the line connecting the centers of two adjacent micro - lenses. If the selected radius of curvature of two corresponding micro - lenses is fixed and it is required that the length of the light spot shape in the direction of the line connecting the centers of two adjacent micro - lenses is longer, then the distance between the centers of two adjacent micro - lenses is larger.

5. The light - homogenizing structure according to claim 1, wherein Within one interval group, the value range of the radius of curvature of the micro - lenses determines the number of micro - lenses in this interval group. The larger the value range of the radius of curvature of the micro - lenses, the more micro - lenses there are in this interval group.

6. The light - homogenizing structure according to claim 1, wherein After the de - spacing treatment of several micro - lenses in the lens array group, a continuous surface is formed on the surface of the light - homogenizing layer.

7. A method for fabricating a microlens array homogenizing structure, characterized in that, Comprising: Providing a base layer, the base layer being a light - transmissive glass sheet; Providing a pattern - forming template, a first pattern structure is formed on the surface of the pattern - forming template, and the first pattern structure is opposite to the structure of the micro - lens array pattern; Providing a shaping glue, using the pattern - forming template as a mold, and through imprinting, shaping the shaping glue onto the base layer to form the micro - lens array pattern on the surface of the base layer, obtaining a micro - lens array light - homogenizing structure; The design and manufacturing method of the micro - lens array pattern specifically includes: Arranging several micro - lenses in multiple adjacent groups, with two adjacent columns forming an interval group. The radius of curvature of the micro - lenses in one column of two adjacent columns is arranged according to the rule of gradually increasing from the middle to both ends, and the radius of curvature of the micro - lenses in the other column of two adjacent columns is arranged according to the rule of gradually decreasing from the middle to both ends; If the number of micro - lenses in one column of the two adjacent columns is N, and the number of micro - lenses in the other column of the two adjacent columns is M, Then, when N > M, the radius of curvature of the lenses in the column with M micro - lenses is greater than the radius of curvature of the lenses in the column with N micro - lenses; When N < M, the radius of curvature of the lenses in the column with M micro - lenses is less than the radius of curvature of the lenses in the column with N micro - lenses; Among them, the values of M and N include integers within 2 - 10, and the values of M and N are adjacent integers.

8. The manufacturing method according to claim 7, wherein The manufacturing method of the pattern - forming template specifically includes: Providing a pattern - forming layer, a second pattern structure is formed on the surface of the pattern - forming layer, and the second pattern structure is the same as the structure of the micro - lens array pattern; Providing a pattern - transfer layer, using the pattern - forming layer as a template, and through imprinting, shaping the shaping glue onto the pattern - transfer layer to form the first pattern structure on the surface of the pattern - transfer layer, obtaining the pattern - forming template.

9. The manufacturing method according to claim 7, wherein The first pattern structure is formed by diamond turning technology to manufacture the pattern - forming template; The pattern - forming template is a metal template.

10. The manufacturing method according to claim 8, wherein A second pattern structure is formed on the surface of the pattern forming layer using diamond turning technology.

11. The manufacturing method according to claim 8, characterized in that, A second pattern structure is formed on the surface of the pattern forming layer, specifically including: Photoresist is uniformly spin-coated onto the surface of the pattern forming layer to form a photoresist layer with a thickness of 5μm-50μm. The photoresist layer is exposed to multiple times at different gray levels, and gray level compensation is performed to form the second pattern structure on the surface of the pattern forming layer.

12. The manufacturing method according to claim 8, characterized in that, A second pattern structure is formed on the surface of the pattern forming layer, specifically including: The pattern forming layer is immersed in a photosensitive resin, and the photosensitive resin is exposed to different gray levels multiple times to form the second pattern structure on the surface of the pattern forming layer.

13. The manufacturing method according to claim 7, characterized in that, The thickness of the base layer ranges from 0.3 mm to 0.6 mm. The refractive index of the substrate layer is greater than or equal to 1.4, and the transmittance of the substrate layer for light in the 930nm-940nm wavelength band is greater than or equal to 90%. The microlens array pattern comprises several microlenses arranged without spacing. The refractive index of the molding compound is greater than or equal to 1.

4. The molding compound is made of resin.

14. The manufacturing method according to claim 7, characterized in that, The microlens array pattern includes several interval groups, which form a lens array group. The center-to-center distance between two adjacent microlenses within a single interval group is 25 μm-120 μm. The microlenses are arranged in a matrix with gaps between them, and the lines connecting the centers of any column of microlenses in the matrix form a straight line.

15. The manufacturing method according to claim 14, characterized in that, A light-homing layer is also formed on the surface of the substrate layer, and a micro-microlens array light-homing structure is formed on the light-homing layer; The microlenses in the lens array are subjected to a de-spacing process. The microlenses after the de-spacing process have different shapes, and the microlenses with different shapes are arranged in a staggered and close manner on the surface of the uniform light layer to form a continuous surface. The shapes of the microlenses after desegmentation include one or more combinations of triangles, quadrilaterals, pentagons, and hexagons.

16. A TOF lens, characterized in that, It includes the micro-microlens array light-uniforming structure according to any one of claims 1-6, wherein the micro-microlens array light-uniforming structure has a lens array group, and an air layer with a thickness ranging from 0.1 mm to 0.5 mm is provided between the lens array group and the laser array light source.

17. A device equipped with a TOF lens, characterized in that, It includes the TOF lens of claim 16, wherein the TOF lens is equipped with a microlens array homogenizing structure according to any one of claims 1-6.

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