Method for measuring actual parameters of optical lens

Abstract

The invention provides a method for measuring actual parameters of an optical lens. The method comprises the following steps: firstly, designing symmetrically arranged detection images; projecting a detection image through the optical lens; collecting energy density data at different positions of the unit measurement image through an energy detection device, and obtaining a data set composed of position coordinates and corresponding energy densities when the energy data are collected; processing and fitting the data in the data set to obtain a corresponding function; extracting an extreme point of the function, and obtaining an actual position coordinate of the unit measurement image based on the extreme point of the function; and according to affine change of a theoretical position coordinate matrix formed by theoretical position coordinates of the unit measurement image and an actual position coordinate matrix formed by actual position coordinates, solving actual parameters of the optical lens. The measurement precision is high, multiple parameters of the optical lens can be obtained through one-time value taking, and the method is simpler and more convenient.

Description

Technical Field

[0001] The present invention relates to a method for measuring actual parameters of an optical lens, especially a method for measuring actual parameters of an optical lens applied to the field of projection exposure. Background Art

[0002] In the field of projection exposure, light rays emitted by a light source are projected onto a substrate through an optical lens to expose the substrate. The optical lens includes a light homogenizing system, a spatial light modulation element, and an imaging lens. The light rays of the light source sequentially pass through the light homogenizing system, the spatial light modulation element, and the imaging lens, and are projected onto the substrate. Accurate measurement of the magnification, angle, translation, and distortion of the imaging lens helps to verify whether the parameters of the lens meet the requirements, timely adjust the lens that does not meet the requirements, and at the same time can provide compensation data for subsequent error compensation to obtain an accurate digital exposure pattern and achieve a good exposure effect.

[0003] Chinese Patent Publication Text CN109270804A discloses a calibration adjustment method for the magnification and deflection angle of a lens of an inclined direct writing exposure machine. The method for obtaining the actual magnification and actual deflection angle of an optical imaging lens is to form reference marking points Mark1 and Mark2 on a DMD, where the coordinates of Mark1 and Mark2 in the DMD coordinate system are (X1, Y1) and (X2, Y2) respectively, and Y1 = Y2; set the distance L between Mark1 and Mark2, the size of a DMD pixel is p, and the distance L between Mark1 and Mark2 is N DMD pixels, then L = |X2 - X1| = N×P; after Mark1 and Mark2 are magnified or reduced by the optical imaging lens, two new marking points Mark3 and Mark4 are formed on the surface of the substrate; by using a high-precision CCD component on the direct writing exposure device, the coordinates of Mark3 and Mark4 are extracted and are respectively denoted as (X3, Y3) and (X4, Y4) in the CCD coordinate system; the difference ΔX in the X direction between Mark3 and Mark4 = |X4 - X3|, the difference ΔY in the Y direction = |Y4 - Y3|, and the absolute distance between Mark3 and Mark4 Calculate the current actual magnification of the optical imaging lens Actual deflection angle

[0004] The above method for obtaining the lens magnification and deflection angle uses the method of calculating the ratio and slope of the distances between two points, and requires the use of a CCD component and dry film imaging on a carrier plate, introducing the error of the CCD component itself and the deviation of dry film imaging, resulting in low measurement accuracy. Summary of the Invention

[0005] In view of the above problems, the present invention provides a method for measuring actual parameters of an optical lens, with high measurement accuracy.

[0006] The technical solution is as follows: A method for measuring the actual parameters of an optical lens. First, a detection image is designed. The detection image includes a plurality of unit detection images, and the detection image is symmetrically arranged. The detection image is projected through the optical lens, and the light image projected through the optical lens is a measurement image. The measurement image corresponds to the detection image and includes a plurality of unit measurement images. An energy detection device is used to collect energy density data at different positions of the unit measurement images respectively, and a data set composed of the position coordinates and the corresponding energy density when collecting the energy data is obtained. The data in the data set is processed and fitted to obtain a corresponding function. The extreme points of the function are extracted, and based on the extreme points of the function, the actual position coordinates of the unit measurement image are obtained. According to the affine transformation of the theoretical position coordinate matrix composed of the theoretical position coordinates of the unit measurement images and the actual position coordinate matrix composed of the actual position coordinates, the actual parameters of the optical lens are solved.

[0007] In one embodiment of the present invention, the number of rows and columns of the unit measurement images of the detection image is odd. The unit measurement image corresponding to the unit detection image located at the central position after being projected through the optical lens is located at the central position of the optical lens, and the remaining unit measurement images are symmetrically arranged in rows and columns with respect to the measurement image at the central position.

[0008] In one embodiment of the present invention, the energy detection device needs to collect an area not less than the unit measurement image.

[0009] In one embodiment of the present invention, the collection range of the energy detection device covers the area of the unit measurement image and the peripheral area of the unit detection image defined by the size of the light passing hole of the energy detection device.

[0010] In one embodiment of the present invention, before fitting the function, the data obtained in the data set can be filtered to remove the noise data, and a data set with smooth changes and no noise is obtained, and a suitable binary polynomial function is fitted to the filtered data set.

[0011] In one embodiment of the present invention, the coordinate system of the energy detection device when collecting the energy data is transformed into the actual coordinate system of the optical lens, and the actual position coordinates of the unit measurement image are obtained.

[0012] In one embodiment of the present invention, when obtaining the coordinates of all unit measurement images in the actual coordinate system of the optical lens, it is obtained by subtracting the actual position coordinates of the unit measurement image located at the center of the measurement image from the coordinates of all extreme points.

[0013] In one embodiment of the present invention, when solving the actual parameters of the optical lens, according to the affine transformation formulas of the theoretical position coordinate matrix formed by the theoretical position coordinates of the unit detection images with the X coordinate matrix and the Y coordinate matrix in the actual position coordinates of the unit measurement images, an actual parameter matrix corresponding to the X coordinate matrix in the actual position coordinates is obtained. The actual parameter matrix includes the magnification value in the X direction of the optical lens, the angle value in the Y direction of the optical lens, and the translation value in the X direction between the theoretical coordinate system and the actual coordinate system, and a change coefficient matrix corresponding to the Y coordinate matrix in the actual position coordinates. The actual parameter matrix includes the angle value in the X direction of the optical lens, the magnification value in the Y direction of the optical lens, and the translation value in the Y direction between the theoretical coordinate system and the actual coordinate system.

[0014] Alternatively, according to the affine transformation formulas of the theoretical position X coordinate matrix formed by the theoretical position coordinates of the unit detection images with the X coordinate matrix and the Y coordinate matrix in the actual position coordinates of the unit measurement images, an actual parameter matrix corresponding to the X coordinate matrix in the actual position coordinates is obtained. The actual parameter matrix includes the magnification value in the X direction of the optical lens and the translation amount in the X direction between the theoretical coordinate system and the actual coordinate system, and a change coefficient matrix corresponding to the Y coordinate matrix in the actual position coordinates. The actual parameter matrix includes the angle value in the X direction of the optical lens and the translation value in the Y direction between the theoretical coordinate system and the actual coordinate system.

[0015] Alternatively, according to the affine transformation formulas of the theoretical position Y coordinate matrix formed by the theoretical position coordinates of the unit detection images with the X coordinate matrix and the Y coordinate matrix in the actual position coordinates of the unit measurement images, an actual parameter matrix corresponding to the X coordinate matrix in the actual position coordinates is obtained. The actual parameter matrix includes the angle value in the Y direction of the optical lens and the translation value in the X direction between the theoretical coordinate system and the actual coordinate system; and a change coefficient matrix corresponding to the Y coordinate matrix in the actual position coordinates. The actual parameter matrix includes the magnification value in the Y direction of the optical lens and the translation value in the Y direction between the theoretical coordinate system and the actual coordinate system.

[0016] In one embodiment of the present invention, when solving the actual parameters of the optical lens, according to the affine transformation formulas of the theoretical position coordinate matrix formed by the theoretical position coordinates of the unit detection images with the difference matrix between the theoretical position X coordinate and the actual position X coordinate of the unit measurement image and the difference matrix between the theoretical position Y coordinate and the actual position Y coordinate of the unit measurement image, a change parameter matrix corresponding to the difference matrix between the theoretical position X coordinate and the actual position X coordinate is obtained. The change coefficient matrix includes a change parameter m corresponding to the magnification value in the X direction of the optical lens. x, the change parameter rv corresponding to the change in the angle value in the Y direction of the optical lens, the translation value in the X direction between the theoretical coordinate system and the actual coordinate system, and the change coefficient matrix corresponding to the difference matrix between the Y coordinate of the theoretical position and the Y coordinate of the actual position of the unit measurement image. The change coefficient matrix includes the change coefficient rx corresponding to the angle value in the X direction of the optical lens and the change coefficient m corresponding to the magnification value in the Y direction of the optical lens y and the translation value in the Y direction between the theoretical coordinate system and the actual coordinate system.

[0017] Or, according to the affine transformation formulas of the theoretical position coordinate matrix formed by the X coordinates of the theoretical positions of the unit detection images respectively with the difference matrix between the X coordinate of the theoretical position and the X coordinate of the actual position of the unit measurement image and the difference matrix between the Y coordinate of the theoretical position and the Y coordinate of the actual position of the unit measurement image, obtain the change parameter matrix corresponding to the difference matrix between the X coordinate of the theoretical position and the X coordinate of the actual position. The change coefficient matrix includes the change parameter m corresponding to the magnification value in the X direction of the optical lens x and the translation value in the X direction between the theoretical coordinate system and the actual coordinate system, and the change coefficient matrix corresponding to the difference matrix between the Y coordinate of the theoretical position and the Y coordinate of the actual position of the unit measurement image. The change coefficient matrix includes the change coefficient r corresponding to the angle value in the X direction of the optical lens x and the translation value in the Y direction between the theoretical coordinate system and the actual coordinate system.

[0018] Or, according to the affine transformation formulas of the theoretical position coordinate matrix formed by the Y coordinates of the theoretical positions of the unit detection images respectively with the difference matrix between the X coordinate of the theoretical position and the X coordinate of the actual position of the unit measurement image and the difference matrix between the Y coordinate of the theoretical position and the Y coordinate of the actual position of the unit measurement image, obtain the change parameter matrix corresponding to the difference matrix between the X coordinate of the theoretical position and the X coordinate of the actual position. The change coefficient matrix includes the change parameter r corresponding to the angle value in the Y direction of the optical lens y and the translation value in the X direction between the theoretical coordinate system and the actual coordinate system, and the change coefficient matrix corresponding to the difference matrix between the Y coordinate of the theoretical position and the Y coordinate of the actual position of the unit measurement image. The change coefficient matrix includes the change coefficient m corresponding to the magnification value in the Y direction of the optical lens y and the translation value in the Y direction between the theoretical coordinate system and the actual coordinate system.

[0019] The actual magnification value in the X direction of the optical lens is equal to (1 - m x ), the actual angle value in the X direction of the optical lens is equal to (1 - r x ), the actual magnification value in the Y direction of the optical lens is equal to (1 - m y ), and the actual angle value in the Y direction of the optical lens is equal to (1 - r y ).

[0020] In one embodiment of the present invention, the distortion value of the optical lens is obtained by substituting the obtained parameter matrix into the original formula to obtain an intermediate value matrix, and the difference between the actual coordinate matrix and the intermediate value matrix is the distortion value of the optical lens.

[0021] In one embodiment of the present invention, a cover plate is provided on the energy detection device, the cover plate is provided with a light passing hole, and the size of the light passing hole is equal to or slightly larger than the size of the unit measurement image.

[0022] A direct writing exposure device applying the measurement method of the actual parameters of the above optical lens, the direct writing exposure device includes a projection mechanism, a substrate platform and a moving mechanism, the projection mechanism includes at least one optical lens, the projection mechanism is used for exposing a workpiece, the substrate platform is located below the optical lens and is used for carrying the workpiece, and the moving mechanism drives the substrate platform and / or the projection mechanism to perform relative movement; the energy detection device is installed on one side of the carrying base through a sliding mechanism, and the energy detection device realizes relative movement with the optical lens in two mutually perpendicular directions through the sliding mechanism and the moving mechanism.

[0023] By obtaining the actual parameters of the optical lens through the above method, dry film imaging is not required, the measurement accuracy is high, and at the same time, multiple parameters of the optical lens can be obtained by taking a single value, and the method is more convenient. Description of the Drawings

[0024] Figure 1 It is a schematic block diagram of the measurement method of the actual parameters of the optical lens.

[0025] Figure 2 It is a schematic diagram of the detection image.

[0026] Figure 3 It is a schematic diagram of the energy detection device.

[0027] Figure 4 It is a schematic diagram of the cover plate.

[0028] Figure 5 It is a schematic diagram of the energy density acquisition trajectory of the unit measurement image.

[0029] Figure 6 It is a schematic diagram of the theoretical coordinate system and the actual coordinate system.

[0030] Figure 7 It is a schematic diagram of the unit measurement image of a single row and a single column.

[0031] Figure 8 It is a schematic diagram of the energy detection mechanism.

[0032] Figure 9 It is a schematic diagram of the fitted function curve. Detailed Description of the Invention

[0033] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention.

[0034] As Figure 1 shown, the measurement method of the actual parameters of the optical lens is to measure the energy density of the projected pattern of the optical lens through an energy detection device, and then obtain the actual magnification value, actual angle value, translation value, and distortion value of the optical lens. The actual angle value refers to the actual installation angle value of the light modulation element DMD in the optical lens.

[0035] When measuring the actual parameters of the optical lens, the following steps are included:

[0036] S1. Design a detection image according to the measurement accuracy. The detection image includes a plurality of unit detection images. The unit detection images are symmetrically arranged in rows and columns. The more the number of unit detection images, the higher the compensation accuracy based on the measurement results. Select a reasonable number of unit detection images according to needs.

[0037] S2. Project the detection image through the optical lens. The light image projected through the optical lens is a measurement image. The measurement image includes unit measurement images corresponding to the unit detection images. Determine the theoretical position coordinates of the unit measurement images in the theoretical coordinate system according to the detection image.

[0038] S3. The energy detection device collects energy density data at different positions of the unit measurement image to obtain a data set composed of the position coordinates and the corresponding energy density when collecting the energy data.

[0039] S4. Process and fit the data in the data set corresponding to the unit measurement image respectively to obtain the corresponding function. The position coordinates when collecting the energy are the independent variables, and the corresponding energy density is the dependent variable.

[0040] S5. Extract the extreme points of the function corresponding to the unit measurement image respectively. Based on the extreme points of the function, obtain the actual position coordinates of the unit measurement image corresponding to the extreme points. The actual position coordinates are the center point position coordinates of the unit measurement image.

[0041] S6. Obtain the actual parameters of the optical lens according to the affine transformation of the theoretical position coordinate matrix composed of the theoretical position coordinates of the unit detection images and the actual position coordinate matrix composed of the actual position coordinates of the unit measurement images. The actual parameters include the actual magnification value, actual angle value, translation amount value, and distortion value.

[0042] In step S1, the number of rows and columns of the unit detection images for detecting the image is odd. The unit measurement image corresponding to the unit detection image at the central position is located at the central position of the optical lens after being projected by the optical lens. The unit detection image at the central position is both in the row at the middle position and in the column at the middle position. The remaining unit measurement images are arranged symmetrically in rows and columns with respect to the unit measurement image at the central position. Preferably, the unit detection images and the unit measurement images are circular or regular polygons.

[0043] In step S2, the theoretical position coordinates of the unit measurement images in the theoretical coordinate system of the optical lens are determined according to the relative position relationship of the unit detection images in the detection image. As Figure 2 shown, the theoretical coordinate system takes the theoretical center of the optical lens as the coordinate origin, determines the coordinate system with the row arrangement direction of the detection image as the X' direction and the column arrangement direction as the Y' direction. According to the order of the unit detection images from left to right and from top to bottom in the detection image, the corresponding theoretical position coordinates of each unit detection image are (X1', Y1'), (X2', Y2')... (0, 0)... (X nm-1 ', Y nm-1 '), (X nm ', Y nm '). The coordinate (0, 0) is the theoretical position coordinate of the unit detection image at the central position, and the coordinate (X nm ', Y nm ') is the theoretical position coordinate of the unit detection image at the lower right position in the detection image. n is the number of rows of the unit detection images in the detection image, m is the number of columns of the unit detection images in the detection image, and nm is the product of the number of rows and columns of the unit detection images.

[0044] In step S3, the energy detection device respectively obtains the data sets of the unit measurement images. For each unit measurement image, the energy detection device needs to collect an area not less than the unit measurement image. As Figure 5As shown in the figure, the preferred acquisition range of the energy detection device covers the area of the unit measurement image and the peripheral area of the unit detection image defined by the size of the light passing hole of the energy detection device, which is convenient for obtaining a complete fitting function curve. When the energy detection device acquires data, it can move uniformly in the Y direction and move step by step in the X direction to different acquisition positions of the unit measurement image to obtain the energy density of the measurement image, covering all the areas to be detected of the measurement image. For example, set the starting position and the ending position of the energy detection device to cover all the areas to be detected of the measurement image. The energy detection device first moves uniformly in the Y direction, then moves in the X direction into the next acquisition area of the unit test image, and then moves uniformly in the Y direction until it reaches the ending position. By setting the step size in the X direction and the position and / or frequency of acquiring data during the uniform movement in the Y direction, the amount of data acquired by the energy detection device can be determined, and the amount of data acquired can be set according to different detection accuracies. For example Figure 3-4 As shown in the figure, a cover plate 2 is provided on the energy detection device 1, and the cover plate 2 is provided with a light passing hole 3, and the area outside the light passing hole 3 is coated with an opaque material. The size of the light passing hole 3 is equal to or slightly larger than the size of the unit measurement image, so as to avoid no difference or too small difference in the energy density obtained at adjacent positions when obtaining the energy density at different positions of the unit measurement image, increasing the amount of data acquisition and reducing the fitting accuracy. The energy detection device can use a photovoltaic cell or other photosensitive components.

[0045] In step S4, the function obtained by fitting each dataset of the unit detection pattern is a binary polynomial function. Before fitting the function, the data obtained from the acquired dataset can be filtered. The filtering method for the dataset can use Gaussian filtering to reduce the influence of noise on the fitting result, obtain a dataset with smooth changes and no noise, and fit a suitable binary polynomial function to the filtered dataset.

[0046] In step S5, the position coordinates when collecting energy in the function use the coordinate system of the energy detection device. It is necessary to transform the coordinate system of the energy detection device into the actual coordinate system of the optical lens to obtain the corresponding actual position coordinates of each unit measurement image. The actual coordinate system of the optical lens can use the actual center of the optical lens as the coordinate origin. In the measurement image, the row arrangement direction of the unit measurement image is the X direction, and the column arrangement direction of the unit measurement image determines the actual coordinate system of the optical lens, and determines the actual position coordinates of the unit measurement image in the actual coordinate system of the optical lens. For example: According to the order of the unit detection images in the measurement image from left to right and from top to bottom, the position coordinates of the extreme points of the functions corresponding to each unit measurement image are (x1, y1), (x2, y2)... (x a , y a )... (x nm-1, y nm-1 ), (x nm , y nm ). The positions of the unit measurement images correspond one-to-one with the positions of the unit detection images. The coordinates (x a , y a ) are the extreme point coordinates of the unit measurement image located at the central position, corresponding to the unit detection image with the theoretical position coordinates (0, 0). The unit measurement image located at the central position of the measurement image is at the actual central position of the lithography lens and has coordinates (0, 0) in the actual coordinate system of the optical lens. When obtaining the coordinates of all unit measurement images in the actual coordinate system of the optical lens, it is obtained by subtracting the coordinates of the extreme points corresponding to all unit measurement images from the coordinates (x a , y a ) of the unit measurement image located at the central position of the measurement image. For example: The X coordinate X1 of the unit measurement image in the first row and first column (the first position) in the actual coordinate system of the optical lens is X1 = x1 - x a , and the Y coordinate Y1 is Y1 = y1 - y a ; The X coordinate X2 of the unit measurement image in the first row and second column (the second position) in the actual coordinate system of the optical lens is X2 = x2 - x a , and the Y coordinate Y2 is Y2 = y2 - y a ; The X coordinate X a of the unit measurement image in the ((n - 1) / 2)th row and ((m - 1) / 2)th column (the a position) (i.e., the unit measurement image located at the central position) in the actual coordinate system of the optical lens is X a = x a - x a = 0, and the Y coordinate Y a is Y a = y nm-1 - y nm-1 = 0. The central position unit measurement image can also be directly obtained without calculation; The X coordinate Y a of the unit measurement image in the nth row and (m - 1)th column (the nm - 1 position) in the actual coordinate system of the optical lens is Y nm-1 = x nm-1 - x a , and the Y coordinate Y nm is Y nm = y a - y nm ; The X coordinate Y nm of the unit measurement image in the nth row and mth column (the nm position) in the actual coordinate system of the optical lens is Y a = x nm-1 , Ynm-1 )、(X nm , Y nm ). The actual position coordinates correspond to the central position coordinates of the unit measurement image in the actual coordinate system.

[0047] In step S6, according to the affine transformation of the theoretical position coordinate matrix formed by the theoretical position coordinates of the unit detection image and the X coordinate matrix and the Y coordinate matrix of the actual position coordinates of the unit measurement image, the first actual parameter matrix corresponding to the X coordinate matrix in the actual position coordinates is obtained, including the magnification value in the X direction of the lens, the angle value in the Y direction of the lens, and the translation value in the X direction between the theoretical coordinate system and the actual coordinate system; the second actual parameter matrix corresponding to the Y coordinate matrix in the actual position coordinates, including the angle value in the X direction of the lens, the magnification value in the Y direction of the lens, and the translation value in the Y direction between the theoretical coordinate system and the actual coordinate system.

[0048] The specific calculation formulas are as follows:

[0049] Let the theoretical position coordinate matrix The first actual parameter The second actual parameter The actual position X coordinate matrix The actual position Y coordinate matrix

[0050] Formula 1: A * B x = C X Expanded as

[0051] Formula 2: A * B y = C y Expanded as

[0052] Where, (X′ u , Y u ′) are the theoretical coordinates, (X u , Y u ) are the actual coordinates, where u is a positive integer between 1 and nm, and both n and m are positive integers not less than 3. M x is the actual magnification in the X direction of the optical lens, R x is the actual rotation angle in the X direction of the optical lens, M y is the actual magnification in the Y direction of the optical lens, R y is the actual rotation angle in the Y direction of the optical lens, T x is the translation amount in the X direction of the actual coordinate system relative to the theoretical coordinate system, T y is the translation amount in the Y direction of the actual coordinate system relative to the theoretical coordinate system.

[0053] By calculating through the above formulas, matrix B can be obtainedx and B y to obtain the actual parameters of the optical lens, including the actual magnification value, translation value, and angle value. Substitute matrix B x into Formula 1, and substitute matrix B y into Formula 2 to obtain matrix C X ’ and matrix C y ’, that is, C X ’ = A * B x ; C y ’ = A * B y

[0054] By obtaining the difference between matrix C X and matrix C X ’, the distortion value Q in the X direction at different positions of the lens is obtained. By obtaining the difference between matrix CY and matrix C x ’, the distortion value Q in the Y direction at different positions of the lens is obtained, that is, Q y ’ = C y - C x ’; Q X = C X - C y ’; Q y = C y ’.

[0055] The calculation of the actual parameters can also be obtained by multiplying the theoretical position coordinate matrix A by the change coefficient matrix to obtain the theoretical position coordinates minus the actual position coordinate matrix, and finally solving to obtain the magnification value, angle value, offset value, and distortion value of the optical lens.

[0056] The specific calculation formula is as follows:

[0057] Let the first change coefficient matrix The second coefficient change matrix

[0058] The difference matrix between the theoretical position coordinates and the actual position X coordinates

[0059] The difference matrix between the theoretical position coordinates and the actual position Y coordinates

[0060] Formula 3: A * e x = D x Expanded as

[0061] Formula 4: A * e y = D y Expanded as

[0062] By calculating the above formulas, the values of the change coefficient matrix are obtained, and then the magnification value, translation value, and angle value of the optical lens are obtained. (1 - mx ) Obtain the actual magnification in the X direction of the optical lens, (1 - r x ) Obtain the actual rotation angle in the X direction of the optical lens, (1 - m y ) Obtain the actual magnification in the Y direction of the optical lens, (1 - r y ) Obtain the actual rotation angle in the Y direction of the optical lens, t x is the translation amount in the X direction of the actual coordinate system relative to the theoretical coordinate system, t y is the translation amount in the Y direction of the actual coordinate system relative to the theoretical coordinate system.

[0063] Substitute e x into formula three to obtain D X ’, e y Substitute into formula four to obtain D y ’, that is, D X ’ = A * e x ; D y ’ = A * e y ;

[0064] Obtain the distortion value Q in the X direction at different positions of the lens x = D X - D X ’; The distortion value Q in the Y direction at different positions of the lens y = D y - D y ’.

[0065] By the above method, the actual magnification value, translation amount value, angle value and distortion value of the optical lens are obtained, which can decouple the interference of the magnification and angle of the optical lens on the distortion test, make the distortion measurement value more accurate, and improve the error compensation accuracy. At the same time, it can verify whether the magnification, installation angle, translation and distortion of the lens meet the usage requirements, with automatic measurement, fast measurement speed and no introduction of human factors, high measurement accuracy and strong traceability.

[0066] In the above embodiment, the detection image is set as a multi - row and multi - column unit detection image. By collecting the energy density at different positions of the unit detection image, the actual magnification value, translation amount value, rotation angle value and distortion value of the optical lens are obtained. If only the parameter requirements of a single coordinate axis (x - axis or y - axis) in the lens coordinate system are concerned during the actual use of the lens, the detection image can also be set in a single - row or single - column manner. The actual magnification M in the X direction of the optical lens is obtained through the unit detection image arranged in a single row x , the actual rotation angle R in the X direction of the optical lens x , the translation amount T in the X direction of the actual coordinate system relative to the theoretical coordinate system x , the translation amount T in the Y direction of the actual coordinate system relative to the theoretical coordinate system y; Measure the image through the cells arranged in a single column to obtain M y is the actual magnification in the Y direction of the optical lens, R y is the actual rotation angle in the Y direction of the optical lens, and the translation amount T in the X direction of the actual coordinate system relative to the theoretical coordinate system x , T y is the translation amount in the Y direction of the actual coordinate system relative to the theoretical coordinate system.

[0067] For the single-row arranged cell detection image, the affine transformation formulas of the X coordinate matrix and the Y coordinate matrix are as follows:

[0068]

[0069]

[0070] For the single-column arranged cell detection image, the affine transformation formulas of the X coordinate matrix and the Y coordinate matrix are as follows:

[0071]

[0072]

[0073] Solve for the lens angles Rx or Ry, magnifications Mx or My, translations Tx and Ty. The calculation method of distortion is the same as that in the above embodiments, and the method is the same as the calculation method for multiple rows and columns, by substituting into the formula to solve for the difference.

[0074] For the single-row and single-column detection image, the theoretical position coordinates can also be obtained by multiplying the X coordinate matrix of the theoretical position by the transformation coefficient matrix or multiplying the Y coordinate matrix of the theoretical position by the transformation coefficient matrix, and then subtracting the actual position coordinate matrix. After calculation, the magnification value, angle value, offset value and distortion value of the optical lens are obtained. The calculation method is as before and will not be elaborated here. According to the parameters to be detected by the optical lens, it is determined to use the single-row arranged cell detection image or the single-column arranged cell detection image.

[0075] The following uses an embodiment specifically applied to a direct writing exposure device to illustrate the measurement method of the magnification, angle and distortion of the optical lens.

[0076] The direct writing exposure device includes a projection mechanism 100, a substrate platform 200, and a moving mechanism (not shown). The projection mechanism 100 includes at least one optical lens 101. The projection mechanism 100 is used to expose the workpiece. The substrate platform 200 is located below the projection mechanism 100 and is used to carry the workpiece. The moving mechanism drives the substrate platform 200 and / or the projection mechanism 100 to perform relative movement. The energy detection device 400 is installed on one side of the substrate platform 200 through a sliding mechanism 500. The energy detection device 400 realizes relative movement with the optical lens 101 in two mutually perpendicular directions through the sliding mechanism 500 and the moving mechanism. Preferably, the moving direction of the sliding mechanism 500 is parallel to the arrangement direction of the optical lenses 101. When the number of the optical lenses 101 is not less than two, the number of the energy detection devices 400 can be one, which respectively collects the energy density data of the optical lenses 101, or one energy detection device is correspondingly arranged for each optical lens 101 to collect the energy data of the optical lenses simultaneously. The energy detection device 400 can be installed on an energy detection board, and the energy detection board is installed on the sliding mechanism 500 through the energy detection board. The energy detection board includes a signal processing unit, which is used to receive the signal of the energy detection device and transmit the signal to an external control and analysis unit. A cover plate is arranged above the energy detection device 400. The cover plate includes a cover plate main body 402 and a light transmission hole 403 arranged on the cover plate main body. Light projects onto the energy detection device 400 through the light transmission hole 403. The cover plate is used to fix the light transmission area, increase the sensitivity of the energy density change, and thus improve the operation accuracy. The size of the light transmission hole 403 in the cover plate is set according to the unit measurement image, and the light transmission hole is equal to or slightly larger than the area of the measurement image.

[0077] Taking the number of optical lenses as 4 and the moving mechanism being arranged below the substrate platform and driving the substrate platform to move relative to the optical lenses as an example, one of the above measurement methods will be specifically described below. Those skilled in the art should know that the above measurement methods can all be applied to this embodiment.

[0078] S1. Design a detection image. The detection image includes 21 unit detection images arranged in three rows and seven columns. The unit detection image is a dot. When the unit detection image located at the central position is projected by the optical lens, it is located at the central position of the optical lens. The unit detection images are arranged in the row direction along the lens arrangement direction.

[0079] S2. Each optical lens projects the detection image separately or simultaneously. The measurement image projected through the optical lens contains 21 unit measurement images. Determine the theoretical position coordinates of the unit measurement images in the theoretical coordinate system according to the detection image and the parameters of the optical lens, which are respectively L1(X1′, Y1′), L2(X2′, Y2′), …… L11 (0, 0) …… L 20 (X 20 ′, Y 20 ′), L 21 (X 21 ′, Y 21 ′).

[0080] S3. The energy detection device is driven by a moving mechanism to move in the Y' direction (the Y direction of the theoretical coordinate system) and is driven by a sliding device to move in the X' direction (the X direction of the theoretical coordinate system). The energy detection device moves at a constant speed in the Y' direction to complete data acquisition in one acquisition area. Then, the energy detection device is driven by the sliding device to move in the X' direction to reach the acquisition position where the energy detection device moves at a constant speed in the Y' direction for the next time. The energy detection device is driven by the moving device to move at a constant speed in the Y' direction to complete multiple data acquisitions. During the process of the energy acquisition device moving at a constant speed, the acquisition frequency of the energy detection device is set according to the moving speed of the energy acquisition device and the sampling quantity requirement of the corresponding energy acquisition area, and the energy density data acquired at different positions of the measurement image is obtained, and a data set composed of the position coordinates of the energy detection device and the corresponding energy density values when collecting energy is obtained.

[0081] S4. The data in the data set corresponding to each unit measurement image is processed and fitted respectively to obtain the corresponding binary polynomial function, where the position coordinates of the energy detection device when collecting energy are the independent variables and the corresponding energy density is the dependent variable.

[0082] S5. The extreme points of the binary polynomial function corresponding to each unit measurement image are extracted, which are A1(x1, y1), A2(x2, y2) …… A 11 (x 11 , y 11 ) …… A 20 (x 20 , y 20 )、A 21 (x 21 , y 21 ). The coordinate system of the energy detection device is transformed into the actual coordinate system of the optical lens to obtain the actual position coordinates of the unit measurement image, which are S1(X1, Y1), S2(X2, Y2) …… S 11 (0, 0) …… S 20 (X 20 , Y 20 ), S 21 (X 21 , Y 21 ).

[0083] S6. Obtain the actual magnification, angle, translation, and distortion of the optical lens based on the affine transformation between the theoretical position coordinate matrix composed of the theoretical position coordinates of the unit measurement image and the actual position coordinate matrix composed of the actual position coordinates.

[0084] Let

[0085] The affine transformation relationship between the X - coordinate matrix of the theoretical coordinate matrix and the actual coordinates:

[0086] Formula Five: a * b x = c X Expanded as

[0087] The affine transformation relationship between the Y - coordinate matrix of the theoretical coordinate matrix and the actual coordinates:

[0088] Formula Six: a * b y = c y Expanded as

[0089] Based on the above two relationships, obtain the magnification M in the X - direction of the actual coordinate system of the optical lens x , the rotation angle R in the X - direction of the actual coordinate system of the optical lens x , the magnification M in the Y - direction of the actual coordinate system of the optical lens y , the rotation R in the Y - direction of the actual coordinate system of the optical lens y , the translation amount T in the X - direction between the actual coordinate system and the theoretical coordinate system x , the translation amount T in the Y - direction between the actual coordinate system and the theoretical coordinate system y . That is, b x and b y matrix, substitute b x into Formula One, and b y into Formula Two to obtain c X ’ and c y ’

[0090] That is, c x ’ = a * b x ; c y ’ = a * b y

[0091] q x = c X - c X ’; q y = c y - c y ’

[0092] q x is the distortion value of the lens at different positions along the X - direction, q yThe distortion value in the Y direction at different positions of the lens.

Claims

1. A method for measuring the actual parameters of an optical lens, characterized in that: First, a detection image is designed, wherein the detection image includes multiple unit detection images, and the detection images are symmetrically arranged; the detection image is projected through the optical lens, and the light image projected by the optical lens is a measurement image, and the measurement image corresponds to the detection image and includes multiple unit measurement images; an energy detection device is used to collect energy density data at different positions of the unit measurement images, and a data set consisting of the position coordinates when the energy data is collected and the corresponding energy density is obtained; the data in the data set is processed and fitted to obtain a corresponding function; the extreme points of the function are extracted, and based on the extreme points of the function, the actual position coordinates of the unit measurement images are obtained; The actual parameters of the optical lens are solved according to the affine changes of the theoretical position coordinate matrix composed of the theoretical position coordinates of the unit measurement images and the actual position coordinate matrix composed of the actual position coordinates.

2. The method for measuring the actual parameters of an optical lens according to claim 1, wherein The number of rows and columns of the unit measurement images of the detection image is an odd number. The unit measurement image corresponding to the unit detection image at the center position after being projected by the optical lens is located at the center position of the optical lens, and the remaining unit measurement images are symmetrically arranged with respect to the rows and columns of the measurement image at the center position.

3. The method for measuring the actual parameters of an optical lens according to claim 1, wherein : The energy detection device needs to collect an area no smaller than the area of the unit measurement image.

4. The method for measuring the actual parameters of an optical lens according to claim 1, wherein The acquisition range of the energy detection device covers the area of the unit measurement image and the peripheral area of the unit detection image defined by the size of the light hole of the energy detection device.

5. The method for measuring the actual parameters of an optical lens according to claim 1, wherein Before fitting the function, the data set obtained can be filtered to remove noise data, obtain a smooth and noise-free data set, and fit a suitable binary multivariate function to the filtered data set.

6. The method for measuring the actual parameters of an optical lens according to claim 1, characterized in that : Transform the coordinate system of the energy detection device when collecting energy data into the actual coordinate system of the optical lens to obtain the actual position coordinates of the unit measurement image.

7. The method for measuring the magnification, angle and distortion of an optical lens according to claim 5, characterized in that When obtaining the coordinates of all unit measurement images in the actual coordinate system of the optical lens, the coordinates of all extreme points are subtracted from the actual position coordinates of the unit measurement image located at the center of the measurement image.

8. The method for measuring the actual parameters of an optical lens according to claim 1, wherein When solving the actual parameters of the optical lens, according to the affine transformation formula of the theoretical position coordinate matrix formed by the theoretical position coordinates of the unit detection image and the X coordinate matrix and the Y coordinate matrix in the actual position coordinates of the unit measurement image, an actual parameter matrix corresponding to the X coordinate matrix in the actual position coordinates is obtained, wherein the actual parameter matrix includes the magnification value of the optical lens in the X direction, the angle value of the optical lens in the Y direction, and the translation value of the theoretical coordinate system and the actual coordinate system in the X direction; and a variation coefficient matrix corresponding to the Y coordinate matrix in the actual position coordinates, wherein the actual parameter matrix includes the angle value of the optical lens in the X direction, the magnification value of the optical lens in the Y direction, and the translation value of the theoretical coordinate system and the actual coordinate system in the Y direction; Alternatively, according to the affine transformation formulas of the X - coordinate matrix of the theoretical position formed by the theoretical position coordinates of the unit detection image with the X - coordinate matrix and the Y - coordinate matrix in the actual position coordinates of the unit measurement image respectively, an actual parameter matrix corresponding to the X - coordinate matrix in the actual position coordinates is obtained. The actual parameter matrix includes the magnification value of the optical lens in the X - direction and the translation amount of the theoretical coordinate system and the actual coordinate system in the X - direction, and a change coefficient matrix corresponding to the Y - coordinate matrix in the actual position coordinates. The actual parameter matrix includes the angular value of the optical lens in the X - direction and the translation value of the theoretical coordinate system and the actual coordinate system in the Y - direction; Alternatively, according to the affine transformation formulas of the Y - coordinate matrix of the theoretical position formed by the theoretical position coordinates of the unit detection image with the X - coordinate matrix and the Y - coordinate matrix in the actual position coordinates of the unit measurement image respectively, an actual parameter matrix corresponding to the X - coordinate matrix in the actual position coordinates is obtained. The actual parameter matrix includes the angular value of the optical lens in the Y - direction and the translation value of the theoretical coordinate system and the actual coordinate system in the X - direction; A change coefficient matrix corresponding to the Y - coordinate matrix in the actual position coordinates. The actual parameter matrix includes the magnification value of the optical lens in the Y - direction and the translation value of the theoretical coordinate system and the actual coordinate system in the Y - direction.

9. The measurement method of the actual parameters of the optical lens according to claim 1, characterized in that: When solving the actual parameters of the optical lens, according to the affine transformation formulas of the difference matrix between the theoretical position X coordinate and the actual position X coordinate of the unit measurement image and the difference matrix between the theoretical position Y coordinate and the actual position Y coordinate of the unit measurement image respectively composed of the theoretical position coordinate matrix of the unit detection image, a change parameter matrix corresponding to the difference matrix between the theoretical position X coordinate and the actual position X coordinate is obtained. The change coefficient matrix includes a change parameter m corresponding to the magnification value in the X direction of the optical lens x , a change parameter r corresponding to the angle value in the Y direction of the optical lens y , and the translation value in the X direction of the theoretical coordinate system and the actual coordinate system. The change coefficient matrix corresponding to the difference matrix between the theoretical position Y coordinate and the actual position Y coordinate of the unit measurement image. The change coefficient matrix includes a change coefficient r corresponding to the angle value in the X direction of the optical lens x , a change coefficient m corresponding to the magnification value in the Y direction of the optical lens y , and the translation value in the Y direction of the theoretical coordinate system and the actual coordinate system; Alternatively, a change parameter matrix corresponding to the difference matrix between the theoretical position X coordinate and the actual position X coordinate is obtained based on the affine change formula of the theoretical position coordinate matrix formed by the theoretical position X coordinate of the unit detection image and the difference matrix between the theoretical position X coordinate and the actual position X coordinate of the unit measurement image, and the difference matrix between the theoretical position Y coordinate and the actual position Y coordinate of the unit measurement image. The change coefficient matrix includes the change parameter m corresponding to the magnification value of the optical lens in the X direction. x The translation value of the theoretical coordinate system and the actual coordinate system in the X direction corresponds to the variation coefficient matrix of the difference matrix between the theoretical position Y coordinate and the actual position Y coordinate of the unit measurement image. The variation coefficient matrix includes the variation coefficient r corresponding to the angle value of the optical lens in the X direction. x And the translation value of the theoretical coordinate system and the actual coordinate system in the Y direction; Alternatively, according to the affine transformation formula of the theoretical position coordinate matrix composed of the theoretical position Y coordinates of the unit detection images respectively with the difference matrix between the theoretical position X coordinates and the actual position X coordinates of the unit measurement images and the difference matrix between the theoretical position Y coordinates and the actual position Y coordinates of the unit measurement images, a transformation parameter matrix corresponding to the difference matrix between the theoretical position X coordinates and the actual position X coordinates is obtained. The transformation coefficient matrix includes the transformation parameter r corresponding to the angle value in the Y direction of the optical lens y and the translation value in the X direction of the theoretical coordinate system and the actual coordinate system, and the transformation coefficient matrix corresponding to the difference matrix between the theoretical position Y coordinates and the actual position Y coordinates of the unit measurement images. The transformation coefficient matrix includes the transformation coefficient m corresponding to the magnification value in the Y direction of the optical lens v and the translation value in the Y direction of the theoretical coordinate system and the actual coordinate system; The actual magnification value of the optical lens in the X direction is equal to (1-m x ), the actual angle value of the optical lens in the X direction is equal to (1-r x ), the actual magnification value of the optical lens in the Y direction is equal to (1-m y ), the actual angle value of the optical lens in the Y direction is equal to (1-r y ).

10. The method for measuring actual parameters of an optical lens according to claim 9 or 10, characterized in that: The distortion value of the optical lens is obtained by substituting the obtained parameter matrix into the original formula to obtain an intermediate value matrix, and the difference between the actual coordinate matrix and the intermediate value matrix is the distortion value of the optical lens.

11. The method for measuring the actual parameters of the optical lens according to claim 1, characterized in that: A cover plate is provided on the energy detection device. The cover plate is provided with a light - passing hole, and the size of the light - passing hole is equal to or slightly larger than the size of the unit measurement image.

12. A direct writing exposure device applying the measurement method of the actual parameters of any one of the optical lenses of claims 1-11, characterized in that: The direct - writing exposure device includes a projection mechanism, a substrate platform, and a moving mechanism. The projection mechanism includes at least one optical lens. The projection mechanism is used to expose a workpiece. The substrate platform is located below the optical lens and is used to carry the workpiece. The moving mechanism drives the substrate platform and / or the projection mechanism to perform relative movement; the energy detection device is installed on one side of the carrying base through a sliding mechanism, and the energy detection device realizes relative movement with the optical lens in two mutually perpendicular directions through the sliding mechanism and the moving mechanism.

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