A method for measuring the sag of a microlens array

Abstract

The present application relates to the technical field of micro-lens array, and particularly relates to a kind of micro-lens array sag measurement methods.The micro-lens array includes a main lens and a plurality of micro-lens groups, and the plurality of micro-lens groups are uniformly distributed on the surface of the main lens from inside to outside, and the micro-lens group includes a plurality of micro-lenses arranged in a circumferential array;The present application measures the highest point of the micro-lens to be measured and the specific coordinates of the points where the two ends of the micro-lens to be measured intersect with the main lens by an optical profilometer, and measures a theoretical third intersection point on the design drawing;By combining theory with practice, the sag of the micro-lens is measured.The present application solves the problem that the existing detection method is difficult to achieve batch detection of micro-lens array.

Description

Technical Field

[0001] This invention relates to the field of microarray lens technology, and more specifically to a method for measuring the sagittal height of a microarray lens. Background Technology

[0002] Microarray lenses, also known as compound eye lenses, are lenses in which tiny lenses, with heights in the nanometer range and apertures in the millimeter or micrometer range, are arranged in an array on a main lens. Similar to traditional lenses, each microlens unit can be a spherical mirror, aspherical mirror, cylindrical mirror, prism, or freeform mirror. Microarray lenses are core optical components in light field imaging systems, performing functions such as focusing, imaging, and beam transformation. Furthermore, due to their small unit size and high integration, microarray lenses can be used to form numerous novel optical systems, achieving functions far exceeding those of traditional optical elements, such as wavefront sensing, light focusing, light shaping, beam collimation, optical interconnection, image recognition and processing, and electro-optic detection.

[0003] Referring to invention patent publication number CN100343622C, a rapid detection method for microlens structural parameters and surface distortion is disclosed. This method involves irradiating the microlens with a light beam to form a diffraction spot, measuring the size of the diffraction spot, and calculating the sag of the microlens based on data such as the shape of the diffraction spot. This detection method is not only complex to operate, but also difficult to perform batch testing of microarray lenses.

[0004] Therefore, it is necessary to provide a technical solution to address the above problems. Summary of the Invention

[0005] This invention relates to a method for measuring the sagittal height of a microarray lens, aiming to solve the problem that existing detection methods are difficult to use for batch detection of microarray lenses.

[0006] To achieve the above objectives, the present invention provides a method for measuring the sagitta of a microarray lens. The microarray lens includes a main lens and a plurality of microlens groups, wherein the plurality of microlens groups are uniformly distributed from the inside to the outside on the surface of the main lens, and each microlens group includes a plurality of microlenses arranged in a circular array. The measurement method includes the following steps:

[0007] S1. Place the microarray lens on the optical profile measuring instrument and position it. Establish a spatial rectangular coordinate system with a point on the center line of the main lens as the origin, and make the center of the microlens to be measured fall directly above the X-axis or Y-axis.

[0008] S2. Control the optical profile measuring instrument to scan and measure along the coordinate axis corresponding to the center of the microlens to be measured;

[0009] S3, according to the scanning result, the highest point of the micro-lens to be measured and the specific coordinates of the points where the two ends of the micro-lens to be measured intersect with the main lens are obtained, the points where the two ends of the micro-lens to be measured intersect with the main lens are respectively denoted as a first intersection point and a second intersection point, the Z-axis coordinate value of the first intersection point is greater than the Z-axis coordinate value of the second intersection point, and the highest point of the micro-lens to be measured is denoted as a sagittal end point;

[0010] S4, in the design diagram of the micro-lens array, the points where the two ends of the micro-lens intersect with the main lens are denoted as a first theoretical intersection point and a second theoretical intersection point, a line segment is obtained by connecting the first theoretical intersection point and the second theoretical intersection point, and a vertical line parallel to the Z-axis and intersecting with the center point of the line segment is drawn, and the vertical line intersects with the main lens at a third theoretical intersection point;

[0011] S5, the sagittal height of the micro-lens is calculated according to the position of the sagittal end point and the position of the third theoretical intersection point.

[0012] More specifically, in step S5, a first value is obtained by subtracting the Z-axis coordinate value of the second intersection point from the Z-axis coordinate value of the sagittal end point, a second value is obtained by subtracting the Z-axis coordinate value of the second theoretical intersection point from the Z-axis coordinate value of the third theoretical intersection point, and the sagittal height of the micro-lens to be measured is obtained by subtracting the second value from the first value.

[0013] More specifically, the side wall of the main lens is provided with a gate cutting part, and the gate cutting part is in a planar shape; the optical profile measuring instrument is provided with a positioning jig, and the positioning jig is provided with a positioning part corresponding to the gate cutting part.

[0014] More specifically, one micro-lens in the micro-lens group is used as a reference lens, and when the gate cutting part on the main lens is in contact with the positioning part on the optical profile measuring instrument, the center of the reference lens is located directly above the X-axis or the Y-axis.

[0015] More specifically, the centers of the reference lenses in the plurality of micro-lens groups are located on the same plane.

[0016] More specifically, in step S1, after the micro-lens array is placed and positioned on the positioning jig of the optical profile measuring instrument, the micro-lens array is measured by the optical profile measuring instrument, and according to the scanning result, the highest point of the main lens is obtained, and the vertical line perpendicular to the horizontal plane with the highest point as the end point is the center line of the main lens.

[0017] More specifically, in step S1, after the optical profile measuring instrument completes the scanning measurement, the curvature radius of the main lens is calculated according to the coordinates of each point measured.

[0018] More specifically, in step S2, the scanning interval of the optical profilometer along the coordinate axis is 0.005mm-0.02mm.

[0019] More specifically, in step S2, the scanning interval of the optical profilometer along the coordinate axis is 0.01mm.

[0020] More specifically, the number of the microlens groups is thirteen, and the microlens groups are arranged from inside to outside as the first group to the thirteenth group, wherein: the number of microlenses in the first group is n, the number of microlenses in the second group is 2n, the number of microlenses in the third group and the fourth group is 3n, the number of microlenses in the fifth group and the sixth group is 4n, the number of microlenses in the seventh group, the eighth group, the ninth group and the tenth group is 6n, and the number of microlenses in the eleventh group, the twelfth group and the thirteenth group is 9n.

[0021] The technical effect of the micro-lens array height measurement method is:

[0022] The optical profilometer is used to measure the coordinates of the first intersection point, the second intersection point and the height end point in the micro-lens array outer contour, and the coordinates of the third theoretical intersection point which cannot be measured by the optical profilometer are calculated in combination with the design drawing, and the height of the micro-lens is analyzed by combining the actual and theoretical values. The measurement method has small error and high measurement efficiency, and realizes industrialized batch detection. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 It is a top view schematic diagram of the micro-lens array lens involved in the application;

[0024] Figure 2 It is a structure schematic diagram of the micro-lens group in the micro-lens array lens involved in the application;

[0025] Figure 3 It is a structure schematic diagram of the micro-lens array lens actually injection molded;

[0026] Figure 4 It is a structure schematic diagram of the micro-lens array lens in an ideal state.

[0027] Markings in the figure:

[0028] 1-main lens; 11-gate cutting part; 2-microlens;

[0029] j-first intersection point; b-second intersection point; a-height end point;

[0030] j'-first theoretical intersection point; b'-second theoretical intersection point; k'-third theoretical intersection point;

[0031] e-first numerical value; d-second numerical value; DETAILED DESCRIPTION

[0032] In order to make the objectives, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely intended to explain the present application and not to limit the present application.

[0033] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or can have a middle element present; when an element is referred to as being "connected to" another element, it can be directly connected to the other element or can have a middle element present.

[0034] In addition, the terms "first", "second", "third", etc. are used only for descriptive purposes and should not be construed as indicating or implying relative importance or an indicated number of technical features. Therefore, the features defined with "first", "second", etc. can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "a plurality of" is two or more, unless otherwise specifically limited.

[0035] In the description of the embodiments of the present application, it should be understood that the directions or position relationships indicated by "up", "down", "front", "back", "left", "right", "top", "bottom", "inner", "outer" and the like are based on the directions or position relationships shown in the drawings, and are only for the convenience of describing the embodiments of the present application and simplifying the description, and therefore should not be construed as indicating or implying that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore should not be construed as limiting the present application.

[0036] In order to more clearly illustrate the technical solutions of the present application, a preferred embodiment is provided below. Specifically referring to Figures 1-4 A micro-lens array lens sag measurement method, wherein: the micro-lens array lens comprises a main lens 1 and a plurality of micro-lens groups, the plurality of micro-lens groups are uniformly distributed on the surface of the main lens 1 from inside to outside, and the micro-lens group comprises a plurality of micro-lenses 2 arranged in a circumferential array; the measurement method comprises the following steps:

[0037] S1, placing the micro-lens array lens on an optical profile measuring instrument and positioning, establishing a space rectangular coordinate system with a point on the center line of the main lens 1 as the coordinate origin, and making the center of the micro-lens 2 to be measured fall directly above the X-axis or Y-axis;

[0038] S2, controlling the optical profile measuring instrument to perform scanning measurement along the coordinate axis corresponding to the center of the micro-lens 2 to be measured;

[0039] S3, according to the scanning result, the highest point of the micro lens 2 to be measured and the specific coordinates of the points where the two ends of the micro lens 2 to be measured intersect with the main lens 1 are obtained, and the points where the two ends of the micro lens 2 to be measured intersect with the main lens 1 are respectively denoted as the first intersection point j and the second intersection point b, the Z-axis coordinate value of the first intersection point j is greater than the Z-axis coordinate value of the second intersection point b, and the highest point of the micro lens 2 to be measured is denoted as the sagittal end point a;

[0040] S4, the points where the two ends of the micro lens 2 intersect with the main lens 1 are marked as the first theoretical intersection point j' and the second theoretical intersection point b' on the design diagram of the micro array lens; a line segment is obtained by connecting the first theoretical intersection point j' and the second theoretical intersection point b', and a vertical line parallel to the Z-axis and intersecting with the center point of the line segment is drawn, the vertical line intersects with the main lens 1 at the third theoretical intersection point k', and the coordinates of the third theoretical intersection point k' are measured on the design diagram;

[0041] S5, the sagittal height of the micro lens 2 is calculated according to the position of the sagittal end point a and the position of the third theoretical intersection point k'.

[0042] Specifically, the micro lens 2 is a spherical mirror, and the third theoretical intersection point k' is the center point of the micro lens 2 in an ideal state. When the actual sagittal height of the micro lens 2 and the theoretical sagittal height of the micro lens 2 are within the tolerance range of 0.0007-0.00095mm, it indicates that the micro lens meets the specifications.

[0043] As a preferred scheme, in step S5, the X-axis coordinate value of the second intersection point b is obtained in the curve diagram scanned by the optical contour measuring instrument, the X-axis coordinate value of the second intersection point b is compared with the X-axis coordinate value of the second theoretical intersection point b', and the micro array lens with a larger error is screened out; then the sagittal height of the micro lens in the remaining micro array lens is calculated by subtracting the coordinate value of the third theoretical intersection point k' from the Z-axis coordinate value of the sagittal end point a, so as to finally select the micro array lens meeting the specifications.

[0044] As another preferred solution, in step S5, a first value e is obtained by subtracting the Z-axis coordinate value of the second intersection point b from the Z-axis coordinate value of the apex point a, a second value d is obtained by subtracting the Z-axis coordinate value of the second theoretical intersection point b' from the Z-axis coordinate value of the third theoretical intersection point k', and the sag of the microlens 2 to be measured is obtained by subtracting the second value d from the first value e. It should be noted that the first value e can be directly measured from the curve obtained by scanning with the optical profiler, and the second value d can be directly measured from the design drawing of the microlens array on a plane or three-dimensional drawing software (such as Autocad software, etc.). The sag calculated by subtracting the second value d from the first value e will not deviate greatly from the theoretical sag only when the apex point a and the second intersection point b do not deviate greatly. Compared with the first calculation scheme, the second calculation scheme can more quickly screen out microlens arrays that do not meet the specifications.

[0045] It should be noted that, unlike the microlens array distributed on the plane mirror, the microlens 2 of the present application is distributed on the main lens 1, and the actual spherical center point of the microlens 2 cannot be directly measured by scanning with the optical profiler. Therefore, in the prior art, how to measure the sag of the microlens 2 on the microlens array has become a big difficulty in the field. The measurement method of the sag of the microlens array according to the present application effectively solves this difficulty. Specifically, the coordinates of the first intersection point j, the second intersection point b and the apex point a in the outer contour of the microlens array are measured by using the optical profiler, and the coordinates of the third theoretical intersection point k' that cannot be measured by the optical profiler are calculated in combination with the design drawing. The sag of the microlens 2 is analyzed by combining the actual and theoretical values. This measurement method not only has small error, but also has high measurement efficiency, and realizes industrialized batch detection.

[0046] Further explanation, refer to Figures 3-4 The radii of curvature of the main lens 1 and the microlens 2 are different, and the scanning measurement result of the optical profiler draws a curve. In the curve, the curves on the front and back sides of the first intersection point j and the second intersection point b change obviously, so that the coordinates of the first intersection point j and the second intersection point b can be clearly and conveniently determined. The highest point of the curve between the first intersection point j and the second intersection point b is the coordinate of the apex point a.

[0047] As a preferred scheme of the embodiment, the peripheral wall of the main lens 1 is provided with a gate cutting part 11, and the gate cutting part 11 is in a planar shape; the optical profile measuring instrument is provided with a positioning jig, and the positioning jig is provided with a positioning part corresponding to the gate cutting part 11. Specifically, in step S1, after the main lens 1 is placed on the optical profile measuring instrument, the main lens 1 is positioned by the gate cutting part 11 being in contact with the positioning part on the optical profile measuring instrument.

[0048] Further, in the microlens group, one microlens 2 is taken as a reference lens, and when the gate cutting part 11 on the main lens 1 is in contact with the positioning part on the optical profile measuring instrument, the center of the reference lens is located directly above the X axis or the Y axis. By using the above design, after the main lens 1 is positioned on the optical profile measuring instrument, the reference lens can be measured as the to-be-measured microlens 2. Referring to Figure 2 , in each microlens group, one to four microlenses can be measured for sag.

[0049] Further, the centers of the reference lenses in the plurality of microlens groups are located on the same plane. By using the above design, after the optical profile measuring instrument is scanned once, the sag of the reference lens in the plurality of microlens groups can be measured, thereby improving the measurement efficiency.

[0050] As a preferred scheme of the embodiment, in step S1, after the microlens array is placed and positioned on the positioning jig of the optical profile measuring instrument, the microlens array is scanned and measured by the optical profile measuring instrument, the highest point of the main lens 1 is obtained according to the scanning result, and a vertical line perpendicular to the horizontal plane with the highest point as an end point is the center line of the main lens 1.

[0051] Further, after the scanning and measurement of the optical profile measuring instrument are completed, according to the coordinates of each point measured, the radius of curvature of the main lens 1 and the horizontal distance between the outer edge of the main lens 1 and the center line can be calculated, so as to screen out part of the unqualified microlens array in advance. In this way, not only the detection period is shortened, but also the error between the actual curvature and the ideal curvature of the main lens 1 in the subsequent detection microlens array is minimized, thereby reducing the error between the third theoretical intersection k' and the third actual intersection, and improving the sag measurement accuracy of the microlens 2.

[0052] Further, the coordinates of the points scanned and measured by the optical profile measuring instrument are (x, y, z), according to the formula , the curvature c of the main lens 1 can be calculated, and then combined with the formula , the radius of curvature R of the main lens 1 can be calculated, and the main lens 1 that does not meet the specifications is screened out according to the calculated radius of curvature R, so as to improve the sag measurement accuracy of the microlens 2.

[0053] As a preferred scheme of the embodiment, in step S2, the scanning interval of the optical profilometer in the coordinate axis scanning is 0.005mm-0.02mm. Specifically, when the scanning interval is too small, the detection efficiency is too low, and when the scanning interval is too large, the positions of the first intersection j, the second intersection b and the height end point a scanned out may deviate, which easily affects the subsequent height calculation accuracy.

[0054] Preferably, in step S2, the scanning interval of the optical profilometer in the coordinate axis scanning is 0.01mm.

[0055] As a preferred scheme of the embodiment, the number of the microlens groups is thirteen, and the microlens groups are arranged from inside to outside as the first group to the thirteenth group, wherein: the number of the microlenses 2 in the first group is n, the number of the microlenses 2 in the second group is 2n, the number of the microlenses 2 in the third group and the fourth group is 3n, the number of the microlenses 2 in the fifth group and the sixth group is 4n, the number of the microlenses 2 in the seventh group, the eighth group, the ninth group and the tenth group is 6n, and the number of the microlenses 2 in the eleventh group, the twelfth group and the thirteenth group is 9n. Specifically, by arranging the microlenses 2 with different numbers of turns and different numbers, the thickness of the microlens array is changed, and then the focal length is changed, so as to achieve the optical effect of different angles.

[0056] The microarray lens height measurement method relates to the present application, which solves the problem that the existing detection method is difficult to achieve batch detection of the microarray lens.

[0057] The above is only the preferred embodiment of the present application, and the structure is not limited to the shapes listed above. Any modification, equivalent replacement and improvement within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A method for measuring the sagittal height of a microarray lens, characterized in that: The microarray lens includes a main lens and several microlens groups, wherein the microlens groups are uniformly distributed from the inside to the outside on the surface of the main lens, and each microlens group includes several microlenses arranged in a circular array; the measurement method includes the following steps: S1. Place the microarray lens on the optical profile measuring instrument and position it. Establish a spatial rectangular coordinate system with a point on the center line of the main lens as the origin, and make the center of the microlens to be measured fall directly above the X-axis or Y-axis. S2. The optical profile measuring instrument scans and measures along the coordinate axis corresponding to the center of the microlens to be measured. S3. Based on the scanning results, obtain the specific coordinates of the highest point of the microlens to be tested and the points where the two ends of the microlens to be tested intersect with the main lens. Let the points where the two ends of the microlens to be tested intersect with the main lens be the first intersection point and the second intersection point, respectively. The Z-axis coordinate value of the first intersection point is greater than the Z-axis coordinate value of the second intersection point. Let the highest point of the microlens to be tested be the sagittal height point. S4. Mark the points where the two ends of the microlens intersect with the main lens in the design drawing of the microarray lens, and record them as the first theoretical intersection point and the second theoretical intersection point; Connect the first theoretical intersection point and the second theoretical intersection point to obtain a line segment, and draw a vertical line parallel to the Z-axis that intersects the center point of the line segment. The vertical line intersects the main lens at the third theoretical intersection point. S5. Calculate the sagittal height of the microlens based on the position of the sagittal height point and the position of the intersection point of the third theory; In step S5, the first value is obtained by subtracting the Z-axis coordinate value of the second intersection point from the Z-axis coordinate value of the sagittal height point, and the second value is obtained by subtracting the Z-axis coordinate value of the second theoretical intersection point from the Z-axis coordinate value of the third theoretical intersection point. The sagittal height of the microlens to be measured is obtained by subtracting the second value from the first value. The main lens has a gate cutting section on its peripheral sidewall, and the gate cutting section is planar; the optical profile measuring instrument is equipped with a positioning fixture, and the positioning fixture has a positioning section corresponding to the gate cutting section; In the microlens group, one microlens is used as the reference lens. When the gate cutting part is in contact with the positioning part of the positioning fixture, the center of the reference lens is located directly above the X-axis or Y-axis. The centers of the reference lenses in several of the microlens groups are located in the same plane; The number of microlens groups is thirteen, and the microlens groups are arranged from the inside to the thirteenth group. Among them, the number of microlenses in the first group is n, the number of microlenses in the second group is 2n, the number of microlenses in the third and fourth groups is 3n each, the number of microlenses in the fifth and sixth groups is 4n each, the number of microlenses in the seventh, eighth, ninth and tenth groups is 6n each, and the number of microlenses in the eleventh, twelfth and thirteenth groups is 9n each.

2. The method for measuring the sagittal height of a microarray lens according to claim 1, characterized in that: In step S1, after the microarray lens is placed and positioned on the positioning fixture of the optical profile measuring instrument, the optical profile measuring instrument scans and measures the microarray lens. Based on the scanning result, the highest point of the main lens is obtained. The perpendicular line drawn from the highest point to the horizontal plane is the center line of the main lens.

3. The method for measuring the sagittal height of a microarray lens according to claim 2, characterized in that: In step S1, after the optical profile measuring instrument completes the scanning measurement, the radius of curvature of the main lens is calculated based on the measured coordinates of each point.

4. The method for measuring the sagittal height of a microarray lens according to claim 1, characterized in that: In step S2, the scanning interval of the optical profile measuring instrument along the coordinate axis is 0.005mm-0.02mm.

5. The method for measuring the sagittal height of a microarray lens according to claim 4, characterized in that: In step S2, the scanning interval of the optical profile measuring instrument along the coordinate axis is 0.01 mm.

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