Uniform light element and method of manufacturing the same

Abstract

The present application provides a method for manufacturing a light homogenizing element, comprising: designing a microlens array, the microlens array comprising a plurality of microlenses, the designing the microlens array comprising: determining a face type of an initial mirror surface of each microlens; determining a height distribution of each microlens, such that the height distribution of each microlens has randomness so as to eliminate interference effect; and forming the microlens array on a substrate, wherein for each microlens, the height distribution of the microlens is determined according to an initial height distribution and a random height distribution, the initial height distribution is determined according to the face type of the initial mirror surface of the microlens, and the random height distribution varies with a position of a surface point of the microlens, the surface point of the microlens being a point on the initial mirror surface of the microlens.

Description

Technical Field

[0001] This invention relates generally to the field of optical technology, and in particular to a light-diffusing element and its manufacturing method. Background Technology

[0002] With the continuous development of technology, light-diffusing sheets are widely used in fields such as TOF ranging, LIDAR (Light Detection and Ranging), and HUD (Head-Up Display).

[0003] Microlens array-based light homogenizers have advantages such as good imaging quality, easy processing, and small size.

[0004] However, due to the interference effect of lasers, the single-aperture microlens (i.e., single microlens) array makes it easy for the homogenizer to have poor homogenization effect, such as uneven target spot, interference bright spots, interference fringes, etc.

[0005] The content of the background section is merely the technology known to the inventor and does not necessarily represent the prior art in this field. Summary of the Invention

[0006] In view of one or more defects in the prior art, especially the fact that the light homogenizer is prone to poor light homogenization effect, such as uneven target light spot, interference fringes, interference bright spots, etc., the present invention provides a light homogenizing element and a method for manufacturing the same.

[0007] According to one aspect of the present invention, a method for manufacturing a light-diffusing element is provided, comprising:

[0008] Design a microlens array, the microlens array comprising multiple microlenses, the designed microlens array comprising:

[0009] Determine the initial mirror surface shape of each microlens;

[0010] The height distribution of each microlens is determined to be random in order to eliminate interference effects;

[0011] The microlens array is formed on the substrate.

[0012] Specifically, for each microlens, the height distribution of the microlens is determined based on an initial height distribution and a random height distribution. The initial height distribution is determined based on the surface shape of the initial mirror surface of the microlens, and the random height distribution varies with the position of a point on the surface of the microlens, which is a point on the initial mirror surface of the microlens.

[0013] According to an embodiment of the present invention, forming the microlens array on a substrate includes: dividing the substrate into multiple grid regions, and arranging the multiple microlenses according to the multiple grid regions.

[0014] According to an embodiment of the present invention, each microlens is matched with the grid region in which it is located.

[0015] According to an embodiment of the present invention, the height distribution of the microlens is obtained by superimposing the random height distribution on the initial height distribution.

[0016] According to an embodiment of the present invention, the random height distribution is determined based on a random coefficient corresponding to the microlens and the local coordinates of the surface points of the microlens, wherein the local coordinates of the surface points of the microlens are the coordinates of the surface points of the microlens in the local coordinate system of the microlens, and the direction of the coordinate axis of the local coordinates is perpendicular to the height direction of the microlens.

[0017] According to an embodiment of the present invention, the random coefficient includes a first random coefficient, and the local coordinates of the surface point of the microlens include the first local coordinates of the surface point of the microlens.

[0018] According to an embodiment of the present invention, the random height distribution is linearly related to the first local coordinates of the surface points of the microlens, and the scaling factor is the first random coefficient.

[0019] According to an embodiment of the present invention, the random coefficient includes a second random coefficient, and the coordinates of the surface point of the microlens include the second local coordinates of the surface point of the microlens.

[0020] According to an embodiment of the present invention, the random height distribution is linearly related to the second local coordinates of the surface points of the microlens, and the scaling factor is the second random coefficient.

[0021] According to an embodiment of the present invention, the random coefficient includes a first random coefficient and a second random coefficient, and the coordinates of the surface point of the microlens include a first local coordinate and a second local coordinate of the surface point of the microlens.

[0022] According to an embodiment of the present invention, the random height distribution is determined based on a first random height distribution and a second random height distribution, wherein the first random height distribution is linearly related to the first local coordinates of the surface points of the microlens, and the scaling factor is the first random coefficient; the second random height distribution is linearly related to the second local coordinates of the surface points of the microlens, and the scaling factor is the second random coefficient.

[0023] According to an embodiment of the present invention, the random height distribution is determined based on a random coefficient corresponding to the microlens, the local coordinates of the surface points of the microlens, and a random constant corresponding to the microlens.

[0024] According to an embodiment of the present invention, a random coefficient corresponding to each microlens is generated by a random number generator.

[0025] According to an embodiment of the present invention, a random number generator generates random coefficients and random constants corresponding to each microlens.

[0026] According to an embodiment of the present invention, the random coefficient corresponding to each microlens ranges from [-1, 1].

[0027] According to an embodiment of the present invention, the random coefficient and random constant corresponding to each microlens range from [-1, 1].

[0028] According to an embodiment of the present invention, the random height distribution is adjusted so as not to change the light intensity distribution on the target plane.

[0029] According to an embodiment of the present invention, if the random height distribution exceeds a predetermined range of the initial height distribution, the random height distribution is adjusted to the predetermined range of the initial height distribution.

[0030] According to an embodiment of the present invention, the random height distribution is adjusted to a predetermined range of the initial height distribution by a scaling factor corresponding to the microlens.

[0031] According to an embodiment of the present invention, the scaling factor is determined by the initial height distribution and aperture of the corresponding microlens.

[0032] According to an embodiment of the present invention, the predetermined range is between 5% and 20%. It should be noted that this numerical range is an empirical value, not a theoretically calculated one.

[0033] According to another aspect of the present invention, a light-diffusing element is provided, comprising:

[0034] Base;

[0035] A microlens array formed on the substrate, the microlens array comprising multiple microlenses, wherein the height distribution of the multiple microlenses is random in order to eliminate interference effects.

[0036] Specifically, for each microlens, the height distribution of the microlens is determined based on an initial height distribution and a random height distribution. The initial height distribution is determined based on the surface shape of the initial mirror surface of the microlens, and the random height distribution varies with the position of a point on the surface of the microlens, which is a point on the initial mirror surface of the microlens.

[0037] According to an embodiment of the present invention, the axis of symmetry of each microlens in the microlens array of the light-diffusing element is not parallel to the optical axis.

[0038] According to an embodiment of the present invention, the axis of symmetry of each microlens in the microlens array of the light-diffusing element is parallel to the normal of the surface formed by their respective random height distribution, wherein the axis of symmetry of each microlens passes through its respective vertex.

[0039] According to an embodiment of the present invention, the axis of symmetry of each microlens in the microlens array is parallel to the normal of the plane formed by their respective random height distribution.

[0040] According to an embodiment of the present invention, the symmetry axis directions of each microlens in the microlens array of the light-diffusing element are at least partially different.

[0041] According to an embodiment of the present invention, the symmetry axis directions of each microlens in the microlens array are different.

[0042] According to another aspect of the present invention, a light-diffusing element is provided, which is manufactured using the method described above.

[0043] The method for manufacturing uniform light elements provided by this invention only requires designing the initial surface shape of each microlens (e.g., the morphology of a single microlens) to ensure that the emitted light meets the design requirements and achieves the desired divergence angle and energy distribution. After designing the initial surface shape of the microlens, simply adding a random height distribution (e.g., a random linear height function) to each microlens can eliminate the interference effect of the microlens array, and the design is relatively quick and simple. Attached Figure Description

[0044] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0045] Figure 1 A schematic flowchart of a method for manufacturing a light-diffusing element according to an embodiment of the present invention is shown.

[0046] Figure 2 An embodiment of the present invention is shown. Figure 1 The flowchart of step S1 is shown.

[0047] Figure 3(a) shows a schematic diagram of the arrangement and height distribution of a first comparative example of a microlens array according to an embodiment of the present invention.

[0048] Figure 3(b) shows a schematic diagram of the arrangement and height distribution of a first application example of a microlens array according to an embodiment of the present invention.

[0049] Figure 3(c) shows a schematic diagram of the arrangement and height distribution of a second application example of a microlens array according to an embodiment of the present invention.

[0050] Figure 3(d) shows a schematic diagram of the arrangement and height distribution of a third application example of a microlens array according to an embodiment of the present invention.

[0051] Figure 4 A schematic diagram of an example optical path according to an embodiment of the present invention is shown.

[0052] Figure 5(a) shows the simulation results of the illuminance distribution of a comparative example of a illuminator according to an embodiment of the present invention.

[0053] Figure 5(b) shows the simulation results of the illuminance distribution of a first application example of a homogenizer according to an embodiment of the present invention.

[0054] Figure 6(a) shows a schematic diagram of the arrangement and height distribution of a second comparative example of a microlens array according to an embodiment of the present invention.

[0055] Figure 6(b) shows a schematic diagram of the arrangement and height distribution of a fourth application example of a microlens array according to an embodiment of the present invention.

[0056] Figure 7(a) shows the simulation results of the illuminance distribution of the light homogenizer based on the microlens array shown in Figure 6(a).

[0057] Figure 7(b) shows the simulation results of the illuminance distribution of the homogenizer based on the microlens array shown in Figure 6(b).

[0058] Figure 8(a) shows a schematic diagram of the morphology of a third comparative example of a microlens array according to an embodiment of the present invention.

[0059] Figure 8(b) shows a schematic diagram of the morphology of a fifth application example of a microlens array according to an embodiment of the present invention. Detailed Implementation

[0060] In the following description, only certain exemplary embodiments are briefly described. As those skilled in the art will recognize, the described embodiments can be modified in various ways without departing from the spirit or scope of the invention. Therefore, the drawings and description are considered to be exemplary in nature and not restrictive.

[0061] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first" or "second" may explicitly or implicitly include one or more of the stated features. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0062] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection, an electrical connection, or a connection that allows for communication; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0063] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0064] The following disclosure provides many different embodiments or examples for implementing various structures of the invention. To simplify the disclosure, specific examples of components and arrangements are described below. These are merely examples and are not intended to limit the invention. Furthermore, reference numerals and / or letters may be repeated in different examples; such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed. In addition, examples of various specific processes and materials are provided in this invention, but those skilled in the art will recognize the application of other processes and / or the use of other materials.

[0065] As can be seen from the background art, existing light homogenizers are prone to problems with poor light homogenization, such as uneven target light spots, interference fringes, interference bright spots, etc.

[0066] To solve the aforementioned technical problem, the present invention provides a method for manufacturing a light-diffusing element, comprising:

[0067] Design a microlens array, the microlens array comprising multiple microlenses, the designed microlens array comprising:

[0068] Determine the initial mirror surface shape of each microlens;

[0069] The height distribution of each microlens is determined to be random in order to eliminate interference effects;

[0070] The microlens array is formed on the substrate.

[0071] Specifically, for each microlens, the height distribution of the microlens is determined based on an initial height distribution and a random height distribution. The initial height distribution is determined based on the surface shape of the initial mirror surface of the microlens, and the random height distribution varies with the position of a point on the surface of the microlens, which is a point on the initial mirror surface of the microlens.

[0072] In the technical solution of this invention, for each microlens, only the initial surface shape of the microlens (e.g., the morphology of a single microlens) needs to be designed so that the emitted light meets the design requirements and achieves the required divergence angle and energy distribution. After designing the initial surface shape of the microlens, only a random height distribution (e.g., a random linear height function) needs to be added to each microlens to eliminate the interference effect of the microlens array. Moreover, the design is relatively fast and simple.

[0073] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0074] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0075] Figure 1 A schematic flowchart of a method for manufacturing a light-diffusing element according to an embodiment of the present invention is shown. Figure 1 As shown, the method may include the following steps:

[0076] S1: Design a microlens array, wherein the microlens array comprises multiple microlenses;

[0077] S2: Form the microlens array on the substrate.

[0078] The substrate material can be, for example, glass, PET (polyethylene terephthalate), PC (polycarbonate), etc. A microlens array (i.e., a microstructure) is disposed on one side surface of the substrate layer. The microstructure includes multiple microlenses, and the microlens material can be, for example, UV (ultraviolet) adhesive. For example, the microlens array can be formed on the substrate using a transfer printing process; specifically, the desired microlens morphology can be formed on the glass surface by UV adhesive nanoimprinting.

[0079] Figure 2 An embodiment of the present invention is shown. Figure 1 The flowchart illustrating step S1 is shown below. Figure 2 As shown, step S1 may include the following steps:

[0080] S11: Determine the initial mirror surface shape of each microlens;

[0081] S12: Determine the height distribution of each microlens so that the height distribution of each microlens is random in order to eliminate interference effects.

[0082] It should be noted that before randomizing the height distribution of each microlens in the microlens array to make the height distribution of each microlens random, firstly, in step S11, the initial surface shape of each microlens (e.g., the morphology of a single microlens) is designed for each microlens, that is, the initial mirror surface shape of the microlens, so that the microlens array can meet the design requirements and obtain the required divergence angle and energy distribution.

[0083] In step S12, for each microlens, the height distribution of the microlens is determined based on an initial height distribution and a random height distribution. The initial height distribution is determined based on the surface shape of the initial mirror of the microlens, and the random height distribution varies with the position of the surface points of the microlens, which are points on the initial mirror of the microlens.

[0084] As an example, in step S12, a random height distribution (e.g., a random linear height function) that varies with the position of the surface point of the microlens is added to each microlens designed in step S11, so that the height distribution of each microlens in the microlens array is random, thereby eliminating the interference effect of the microlens array, and is relatively quick and simple to design.

[0085] In some embodiments of the present invention, step S2, namely forming the microlens array on the substrate, includes: dividing the substrate into multiple grid regions and arranging the multiple microlenses according to the multiple grid regions.

[0086] In other words, each microlens in the microlens array is arranged in a corresponding grid on the substrate.

[0087] In some embodiments of the present invention, each microlens is matched with the grid region in which it is located.

[0088] In other words, each microlens in the microlens array matches the corresponding grid on the substrate in size and shape.

[0089] Specifically, the microlenses in the microlens array are arranged on multiple grid regions of the substrate, and each grid region of the substrate can be of a regular shape or an irregular shape.

[0090] In other words, the arrangement of multiple microlenses in a microlens array can be regular or irregular.

[0091] For each microlens, for example, for a single microlens, the design of the initial surface profile (i.e., the initial mirror profile) of a single microlens in step S11 will be illustrated below.

[0092] For the initial mirror surface of a single microlens, its surface shape formula can be expressed as an xy polynomial. Specifically, the surface shape formula for the initial mirror surface of a single microlens can be:

[0093]

[0094] In the above formula, x and y are the abscissa and ordinate of the surface point of the microlens in the local coordinate system of the microlens, respectively. The x-axis and y-axis are perpendicular to the height direction of the microlens. The origin of the local coordinate system of the microlens is the position of the initial vertex (i.e., the center of the microlens) of the microlens, and the surface point of the microlens is the point on the initial mirror surface of the microlens.

[0095] c is the curvature;

[0096] k is the cone constant;

[0097] NR is the normalized radius;

[0098] Aij For x i y j The coefficient;

[0099] i and j are pointers to terms in the polynomial;

[0100] This represents the distance between the current coordinate (x, y) position and the center of the microlens.

[0101] It should be noted that all parameters in the surface shape formula are obtained through optimization algorithms. For example, by setting an optimization function, such as the divergence angle of the target light spot or the target energy distribution, each parameter is obtained through optimization. The purpose of optimizing the surface shape is to ensure that the microlens array meets the design requirements and obtains the desired divergence angle and energy distribution.

[0102] After designing the surface shape formula of the initial mirror of a single microlens, the initial height distribution H0(x,y) of the microlens can be determined according to the surface shape formula Z(x,y) of the initial mirror of the microlens.

[0103] For example, H0(x,y) = Z(x,y).

[0104] In other words, the initial height of a single microlens is the formula for the surface shape of its initial mirror.

[0105] After designing the surface shape formula of the initial mirror of a single microlens and thereby determining the initial height of the microlens, the height distribution of the microlens is randomized to make the height distribution of the microlens random.

[0106] In some embodiments of the present invention, for each microlens, the height distribution of the microlens is obtained by superimposing a random height distribution on its initial height distribution.

[0107] As an example, the height distribution of the microlens is H(x,y) = H0(x,y) + h(x,y).

[0108] Where h(x,y) represents the random height distribution of the microlens.

[0109] In this way, a random height distribution is superimposed on the initial height distribution of each microlens, increasing the randomness of the microlens array. Therefore, even if the microlenses are arranged in a regular pattern, interference effects can be well suppressed.

[0110] Specifically, for each microlens, the random height distribution of the microlens is determined based on the random coefficient corresponding to the microlens and the local coordinates of the surface point of the microlens. The local coordinates of the surface point of the microlens are the coordinates of the surface point of the microlens in the local coordinate system of the microlens, and the direction of the coordinate axis of the local coordinates is perpendicular to the height direction of the microlens.

[0111] It should be noted that the surface point of the microlens is a point on the initial mirror surface of the microlens, and the origin of the local coordinate system of the microlens is the position of the initial vertex of the microlens.

[0112] It can be seen that the random height distribution of each microlens depends on its corresponding random coefficient and varies with the local coordinates of the surface points of the microlens. Therefore, the increased randomness of the height distribution of the microlens array can better suppress the interference effect of the microlens array.

[0113] In some embodiments of the present invention, the random coefficient corresponding to the microlens includes a first random coefficient, and the local coordinates of the surface point of the microlens include the first local coordinates of the surface point of the microlens.

[0114] In other words, the random height distribution of each microlens depends on its corresponding random coefficient (i.e., the first random coefficient), and the random height distribution of the microlens varies with a local coordinate of a surface point of the microlens. Therefore, the increased randomness of the height distribution of the microlens array can better eliminate the interference effect of the microlens array.

[0115] Specifically, the random height distribution of the microlens is linearly related to the first local coordinates of the surface points of the microlens, and the scaling factor is the first random coefficient.

[0116] In some embodiments of the present invention, the random coefficient corresponding to the microlens includes a second random coefficient, and the local coordinates of the surface point of the microlens include the second local coordinates of the surface point of the microlens.

[0117] In other words, the random height distribution of each microlens depends on its corresponding random coefficient (i.e., the second random coefficient), and the random height distribution of the microlens varies with another local coordinate of the surface point of the microlens. Therefore, the increased randomness of the height distribution of the microlens array can better eliminate the interference effect of the microlens array.

[0118] Specifically, the random height distribution of the microlens is linearly related to the second local coordinates of the surface points of the microlens, and the scaling factor is the second random coefficient.

[0119] In some embodiments of the present invention, the random coefficients corresponding to the microlens include a first random coefficient and a second random coefficient, and the local coordinates of the surface points of the microlens include the first local coordinates and the second local coordinates of the surface points of the microlens.

[0120] In other words, the random height distribution of each microlens depends on its two corresponding random coefficients (i.e., the first random coefficient and the second random coefficient), and the random height distribution of the microlens varies with the two local coordinates of the surface points of the microlens. Therefore, the randomness of the height distribution of the microlens array is further enhanced, which can better suppress the interference effect of the microlens array.

[0121] Specifically, the random height distribution of the microlens is determined based on a first random height distribution and a second random height distribution, wherein the first random height distribution is linearly related to the first local coordinates of the surface points of the microlens, and the scaling factor is the first random coefficient; the second random height distribution is linearly related to the second local coordinates of the surface points of the microlens, and the scaling factor is the second random coefficient.

[0122] In some embodiments of the present invention, the random height distribution of the microlens is determined based on the random coefficients corresponding to the microlens, the local coordinates of the surface points of the microlens, and the random constants corresponding to the microlens.

[0123] In other words, the random height distribution of each microlens depends on its corresponding random coefficient, and the random height distribution of the microlens changes with the local coordinates of the surface points of the microlens. Furthermore, the initial height of each microlens is also superimposed with its corresponding random constant. Therefore, the randomness of the height distribution of the microlens array is further enhanced, which can further suppress the interference effect of the microlens array.

[0124] As an example, a microlens array may include n microlenses, with a random height distribution h of microlenses i (i = 1, ..., n). i (x i ,y i ) = h 1i (x i ,y i )+h 2i (x i ,y i )+c i ,

[0125] Where, x i and y iLet x and y be the abscissa (i.e., the first local coordinate) and ordinate (i.e., the second local coordinate) of a surface point of microlens i in the local coordinate system of microlens i, respectively. The origin of the local coordinate system of microlens i is the initial vertex position of microlens i, and the surface point of microlens i is the point on the initial mirror surface of microlens i.

[0126] h 1i (x i ,y i ) represents the first random height distribution of microlens i.

[0127] h 2i (x i ,y i ) represents the second random height distribution of microlens i.

[0128] c i Let be a random constant for microlens i.

[0129] Optionally, a random constant c corresponding to microlens i is generated using a random number generator. i .

[0130] Optionally, the random constant c corresponding to microlens i i The value range is [-1, 1].

[0131] Specifically, the first random height distribution h of microlens i 1i (x i ,y i ) = a i x i ,

[0132] a i Let be the first random coefficient of microlens i.

[0133] As shown in the above formula, the random height distribution h of the microlens i i (x i ,y i The x-coordinate of the surface point of microlens i i The (i.e., first local coordinates) show a linear relationship, with a scaling factor of a. i .

[0134] Optionally, a first random coefficient a corresponding to microlens i is generated by a random number generator. i .

[0135] Optionally, the first random coefficient a corresponding to microlens i i The value range is [-1, 1].

[0136] Specifically, the second random height distribution h of the microlenses i (i = 1, ..., n) 2i (x i,y i )=b i y i ,

[0137] b i is the second random coefficient of microlens i.

[0138] As shown in the above formula, the random height distribution h of the microlens i i (x i ,y i The coordinates of the surface point of microlens i are linearly related to the coordinates of the surface point of microlens i (i.e., the second local coordinates), with a scaling factor of b. i .

[0139] Optionally, a second random coefficient b corresponding to the microlens i is generated by a random number generator. i .

[0140] Optionally, the second random coefficient b corresponding to microlens i i The value range is [-1, 1].

[0141] As another example, the random height distribution h of microlens i i (x i ,y i ) = a i x i At this time h 2i (x i ,y i ) = 0 or b i =0, and c i =0.

[0142] As another example, the random height distribution h of microlens i i (x i ,y i ) = a i x i +c i At this time h 2i (x i ,y i ) = 0 or b i =0.

[0143] As another example, the random height distribution h of microlens i i (x i ,y i )=b i y i At this time h 1i (x i ,y i ) = 0 or a i =0, and c i =0.

[0144] As another example, the random height distribution h of microlens i i (x i ,y i )=b i y i +c i At this time h 1i (x i ,y i ) = 0 or a i =0.

[0145] As another example, the random height distribution h of microlens i i (x i ,y i ) = h 1i (x i ,y i )+h 2i (x i ,y i ), at this time c i =0.

[0146] In addition, in order to ensure that the superimposed random height distribution does not change the light intensity distribution on the target plane, the random height distribution needs to be adjusted.

[0147] By adjusting the random height distribution, the microlens array can meet the design requirements and obtain the desired divergence angle and energy distribution.

[0148] Specifically, if the random height distribution exceeds a predetermined range of the initial height distribution, the random height distribution is adjusted to the predetermined range of the initial height distribution.

[0149] In some embodiments of the present invention, the random height distribution is adjusted to a predetermined range of the initial height distribution by a scaling factor corresponding to the microlens.

[0150] Specifically, the scaling factor is determined by the initial height distribution and aperture of the corresponding microlens.

[0151] As an example, the random height distribution h of microlens i i (x i ,y i )=d i *h 0i (x i ,y i ),

[0152] Among them, h 0i (x i ,y i ) represents the random height distribution of microlens i before adjustment.

[0153] d i This represents the scaling factor corresponding to microlens i, and the scaling factor d is... i It is determined by the initial height distribution and aperture of microlens i, and is used to adjust h. 0i (x i ,y i This causes the random height distribution h of microlens i to be... i (x i ,y i It falls within a predetermined range of the initial height of microlens i.

[0154] Preferably, the predetermined range is between 5% and 20%. Based on experience, this setting better meets design requirements and achieves the desired divergence angle and energy distribution.

[0155] Correspondingly, the present invention also provides a light-diffusing element, which is manufactured using the above-described method.

[0156] Correspondingly, the present invention also provides a light-diffusing element, comprising:

[0157] Base;

[0158] A microlens array formed on the substrate, the microlens array comprising multiple microlenses, wherein the height distribution of the multiple microlenses is random in order to eliminate interference effects.

[0159] Specifically, for each microlens, the height distribution of the microlens is determined based on an initial height distribution and a random height distribution. The initial height distribution is determined based on the surface shape of the initial mirror surface of the microlens, and the random height distribution varies with the position of a point on the surface of the microlens, which is a point on the initial mirror surface of the microlens.

[0160] The light-uniforming element provided by this invention has a morphology of each microlens in the microlens array designed to make the emitted light meet the design requirements, achieving the required divergence angle and energy distribution. Each microlens exhibits a random height distribution, making the height distribution of the microlens array random, which can eliminate the interference effect of the microlens array, improve the light-uniforming effect of the light-uniforming sheet based on the microlens array, make the target light spot more uniform, that is, the light spot distribution is more compact, the light spot brightness difference is smaller, and interference bright spots, interference fringes, etc. are eliminated.

[0161] In some embodiments of the present invention, the axis of symmetry of each microlens in the microlens array of the light-diffusing element is not parallel to the optical axis.

[0162] In some embodiments of the present invention, the axis of symmetry of each microlens in the microlens array of the light-diffusing element is parallel to the normal of the surface formed by their respective random height distribution, wherein the axis of symmetry of each microlens passes through its respective vertex.

[0163] Specifically, the axis of symmetry of each microlens in the microlens array is parallel to the normal of the plane formed by their respective random height distribution.

[0164] The surface formed by the random height distribution (i.e., linear random height function) of the individual microlenses in the microlens array is a plane.

[0165] In some embodiments of the present invention, the symmetry axis directions of the individual microlenses in the microlens array of the light-diffusing element are at least partially different.

[0166] This makes the morphology of the microlens array random, suppressing interference effects.

[0167] Specifically, the symmetry axis directions of each microlens in the microlens array are different.

[0168] Figure 3(a) shows a schematic diagram of the arrangement and height distribution of a first comparative example of a microlens array according to an embodiment of the present invention. As shown in Figure 3(a), the microlens array is composed of a regular arrangement of single lenses. In this case, the height distribution of each microlens in the microlens array is not random, that is, the random height distribution h superimposed on any microlens i is... i (x i ,y i Since ) = 0, there will be a strong interference effect.

[0169] Figure 3(b) shows a schematic diagram of the arrangement and height distribution of a first application example of a microlens array according to an embodiment of the present invention. As shown in Figure 3(b), the individual microlenses in the microlens array are arranged regularly, but the height distribution of the individual microlenses in the microlens array is random. Specifically, a random height distribution h is superimposed on microlens i. i (x i ,y i ) = a i x i In this way, interference effects can be effectively suppressed even when the microlenses are arranged in a regular pattern.

[0170] Figure 3(c) shows a schematic diagram of the arrangement and height distribution of a second application example of a microlens array according to an embodiment of the present invention. As shown in Figure 3(b), the individual microlenses in the microlens array are arranged regularly, but the height distribution of the individual microlenses in the microlens array is random. Specifically, a random height distribution h is superimposed on microlens i. i (x i ,y i)=b i y i In this way, interference effects can be effectively suppressed even when the microlenses are arranged in a regular pattern.

[0171] Figure 3(d) shows a schematic diagram of the arrangement and height distribution of a third application example of a microlens array according to an embodiment of the present invention. As shown in Figure 3(d), the individual microlenses in the microlens array are arranged regularly, but the height distribution of each microlens in the microlens array is random. Specifically, a random height distribution h is superimposed on microlens i. i (x i ,y i ) = a i x i +b i y i +c i In this way, interference effects can be better suppressed even if the microlenses are kept in a regular arrangement.

[0172] Compared with Figure 3(a), the height distribution of the microlens array in Figures 3(b)-(d) is random, which can eliminate the interference effect of the microlens array and thus improve the light homogenization effect of the light homogenizer based on the microlens array.

[0173] Figure 3(d) and Figure 3(b) , 3(c) In comparison, the randomness of the height distribution of the microlens array is further enhanced, which can better eliminate the interference effect of the microlens array, thereby better improving the light homogenization effect of the light homogenizer based on the microlens array.

[0174] Figure 4 A schematic diagram illustrating an example of an optical path according to an embodiment of the present invention is shown. Figure 4 As shown, the light homogenizer includes a substrate glass and a microlens array layer. The microlens array is regularly arranged on a uniform grid on the substrate. The light homogenizer expands the incident collimated light to achieve the target's field of view (FOV).

[0175] For example, UV adhesive nanoimprinting can be used to form the desired microlens morphology on the glass surface.

[0176] Figure 5(a) shows the simulation results of the illuminance distribution of a comparative example of a light-diffusing plate according to an embodiment of the present invention. Figure 5(a) shows the simulation results of the illuminance distribution on a detection plane located 200 mm behind the light-diffusing plate. The height distribution of each microlens in the microlens array of the light-diffusing plate is not random, and therefore there is a strong interference effect. As shown in Figure 5(a), due to the interference effect of light, the illuminance distribution exhibits a discrete point cloud.

[0177] Figure 5(b) shows the simulation results of the illuminance distribution of a first application example of a homogenizer according to an embodiment of the present invention. Figure 5(b) shows the simulation results of the illuminance distribution on a detection plane located 200 mm behind the homogenizer. The height distribution of each microlens in the microlens array of the homogenizer is random, i.e., a random height distribution is superimposed on each microlens, thus suppressing the interference effect of the microlens array. Compared with Figure 5(a), in Figure 5(b), the illuminance distribution becomes more uniform, the spot distribution is more compact, the difference in spot brightness is smaller, and the interference effect is improved. It can be seen that by superimposing a random height distribution on each microlens, the phases of each microlens are staggered, thereby disturbing the phase and eliminating interference.

[0178] Figure 6(a) shows a schematic diagram of the arrangement and height distribution of a second comparative example of a microlens array according to an embodiment of the present invention. As shown in Figure 6(a), the individual microlenses of the microlens array are arranged irregularly, but the height distribution of the individual microlenses in the microlens array is not random.

[0179] Figure 6(b) shows a schematic diagram of the arrangement and height distribution of a fourth application example of a microlens array according to an embodiment of the present invention. As shown in Figure 6(b), the individual microlenses of the microlens array are arranged irregularly, and the height distribution of the individual microlenses in the microlens array is random, that is, the individual microlenses in the microlens array have a superimposed random height distribution.

[0180] Figure 7(a) shows the simulation results of the illuminance distribution of the homogenizer based on the microlens array shown in Figure 6(a). Figure 7(a) shows the simulation results of the illuminance distribution on the detection plane located 200 mm behind the homogenizer. This homogenizer is based on the microlens array shown in Figure 6(a). The height distribution of each microlens in this microlens array is not random, thus resulting in a strong interference effect. As shown in Figure 7(a), due to the light interference effect, the illuminance distribution exhibits severely discrete bright spots near the center of the detection plane.

[0181] Figure 7(b) shows the simulation results of the illuminance distribution of the homogenizer based on the microlens array shown in Figure 6(b). Figure 7(b) shows the simulation results of the illuminance distribution on the detection plane located 200 mm behind the homogenizer. This homogenizer is based on the microlens array shown in Figure 6(b), in which the height distribution of each microlens is random, i.e., random height distributions are superimposed on each microlens, thus suppressing the interference effect of the microlens array. Compared with Figure 7(a), in Figure 7(b), the illuminance distribution is more uniform, the spot distribution is more compact, the difference in spot brightness is smaller, interference bright spots are eliminated, and the interference effect is improved. It can be seen that by superimposing random height distributions on each microlens, the phases of each microlens are staggered, thereby disturbing the phase and eliminating interference.

[0182] Figure 8(a) shows a schematic diagram of the morphology of a third comparative example of a microlens array according to an embodiment of the present invention. In Figure 8(b), the dashed arrows represent the optical axes of the entire optical path system (including the light source, homogenizer, detector, etc.), and the dotted lines represent the axes of symmetry of each microlens. The axes of symmetry of each microlens pass through their respective vertices, and the axes of symmetry of each microlens are along the direction of the optical axis. In the microlens array shown in Figure 8(a), the individual microlenses do not have a random height distribution. As shown in Figure 8(a), in the microlens array, the height distribution of each microlens is not random, the axes of symmetry of each microlens are in the same direction (i.e., parallel), and the morphology of the microlens array is not random, thus resulting in a strong interference effect.

[0183] Figure 8(b) shows a schematic diagram of the morphology of a fifth application example of a microlens array according to an embodiment of the present invention. In Figure 8(b), the dashed arrows represent the optical axes of the entire optical path system (including the light source, homogenizer, detector, etc.), and the dotted lines represent the axes of symmetry of each microlens, which pass through their respective vertices. Compared with Figure 8(a), in the microlens array shown in Figure 8(b), each microlens is superimposed with a random height distribution. As shown in Figure 8(b), the axis of symmetry of each microlens is not parallel to the optical axis direction, and the directions of the axes of symmetry of each microlens are also different, resulting in a random morphology of the microlens array, thereby suppressing interference effects. Furthermore, as shown in Figure 8(b), the thick arrows represent the normals of the surfaces formed by the random height distributions (random height functions) of each microlens, and the axes of symmetry of each microlens are parallel to the normals of the surfaces formed by their respective random height distributions.

[0184] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for manufacturing a light-diffusing element, comprising: Design a microlens array, the microlens array comprising multiple microlenses, the designed microlens array comprising: Determine the initial mirror surface shape of each microlens; The height distribution of each microlens is determined to be random in order to eliminate interference effects; The microlens array is formed on the substrate. Specifically, for each microlens, the height distribution of the microlens is determined based on an initial height distribution and a random height distribution. The initial height distribution is determined based on the surface shape of the initial mirror of the microlens, and the random height distribution varies with the position of the surface points of the microlens, where the surface points are points on the initial mirror of the microlens. The height distribution of the microlens is obtained by superimposing the random height distribution on the initial height distribution; The random height distribution is determined based on the random coefficient corresponding to the microlens and the local coordinates of the surface points of the microlens. The local coordinates of the surface points of the microlens are the coordinates of the surface points of the microlens in the local coordinate system of the microlens, and the direction of the coordinate axis of the local coordinates is perpendicular to the height direction of the microlens.

2. The method according to claim 1, characterized in that, Forming the microlens array on a substrate includes: dividing the substrate into multiple grid regions and arranging the multiple microlenses according to the multiple grid regions.

3. The method according to claim 2, characterized in that, Each microlens is matched to the grid region it belongs to.

4. The method according to claim 1, characterized in that, The random coefficients include a first random coefficient, and the local coordinates of the surface points of the microlens include the first local coordinates of the surface points of the microlens.

5. The method according to claim 4, characterized in that, The random height distribution is linearly related to the first local coordinates of the surface points of the microlens, and the scaling factor is the first random coefficient.

6. The method according to claim 1, characterized in that, The random coefficients include a second random coefficient, and the coordinates of the surface points of the microlens include the second local coordinates of the surface points of the microlens.

7. The method according to claim 6, characterized in that, The random height distribution is linearly related to the second local coordinates of the surface points of the microlens, and the scaling factor is the second random coefficient.

8. The method according to claim 1, characterized in that, The random coefficients include a first random coefficient and a second random coefficient, and the coordinates of the surface points of the microlens include a first local coordinate and a second local coordinate of the surface points of the microlens.

9. The method according to claim 8, characterized in that, The random height distribution is determined based on a first random height distribution and a second random height distribution, wherein the first random height distribution is linearly related to the first local coordinates of the surface points of the microlens, and the scaling factor is the first random coefficient; the second random height distribution is linearly related to the second local coordinates of the surface points of the microlens, and the scaling factor is the second random coefficient.

10. The method according to claim 1, characterized in that, The random height distribution is determined based on the random coefficients corresponding to the microlens, the local coordinates of the surface points of the microlens, and the random constants corresponding to the microlens.

11. The method according to claim 1, characterized in that, A random coefficient corresponding to each microlens is generated using a random number generator.

12. The method according to claim 10, characterized in that, A random number generator is used to generate random coefficients and random constants corresponding to each microlens.

13. The method according to claim 1, characterized in that, The random coefficient corresponding to each microlens ranges from [-1, 1].

14. The method according to claim 10, characterized in that, The range of values ​​for the random coefficients and random constants corresponding to each microlens is [-1, 1].

15. The method according to claim 1, characterized in that, The random height distribution is adjusted so as not to change the light intensity distribution on the target plane.

16. The method according to claim 15, characterized in that, If the random height distribution exceeds the predetermined range of the initial height distribution, the random height distribution is adjusted to the predetermined range of the initial height distribution.

17. The method according to claim 16, characterized in that, The random height distribution is adjusted to a predetermined range of the initial height distribution by a scaling factor corresponding to the microlens.

18. The method according to claim 17, characterized in that, The scaling factor is determined by the initial height distribution and aperture of the corresponding microlens.

19. The method according to claim 16, characterized in that, The predetermined range is between 5% and 20%.

20. A light-diffusing element, comprising: Base; A microlens array formed on the substrate, the microlens array comprising multiple microlenses, wherein the height distribution of the multiple microlenses is random in order to eliminate interference effects. Specifically, for each microlens, the height distribution of the microlens is determined based on an initial height distribution and a random height distribution. The initial height distribution is determined based on the surface shape of the initial mirror of the microlens, and the random height distribution varies with the position of the surface points of the microlens, where the surface points are points on the initial mirror of the microlens. The height distribution of the microlens is obtained by superimposing the random height distribution on the initial height distribution; The random height distribution is determined based on the random coefficient corresponding to the microlens and the local coordinates of the surface points of the microlens. The local coordinates of the surface points of the microlens are the coordinates of the surface points of the microlens in the local coordinate system of the microlens, and the direction of the coordinate axis of the local coordinates is perpendicular to the height direction of the microlens.

21. The light-diffusing element according to claim 20, characterized in that, The axis of symmetry of each microlens in the microlens array of the light-diffusing element is not parallel to the optical axis.

22. The light-diffusing element according to claim 20, characterized in that, The axis of symmetry of each microlens in the microlens array of the light-diffusing element is parallel to the normal of the surface formed by its respective random height distribution, wherein the axis of symmetry of each microlens passes through its respective vertex.

23. The light-diffusing element according to claim 22, characterized in that, The axis of symmetry of each microlens in the microlens array is parallel to the normal of the plane formed by their respective random height distribution.

24. The light-diffusing element according to claim 22, characterized in that, The symmetry axis directions of each microlens in the microlens array of the light-diffusing element are at least partially different.

25. The light-diffusing element according to claim 24, characterized in that, The symmetry axes of each microlens in the microlens array are not in the same direction.

26. A light-diffusing element, characterized in that, It is manufactured using the method described in any one of claims 1-19.

Images