Z-axis platform perpendicularity calibration compensation method and device and storage medium

Abstract

This invention discloses a method, apparatus, and storage medium for Z-axis platform verticality calibration compensation. The method includes the following steps: S1, placing a camera above the Z-axis platform so that the Z-axis platform constantly falls within the imaging area of ​​the camera within a preset height range; S2, controlling the Z-axis platform to move along the Z-axis direction a preset number of times, so that the Z-axis platform reaches a specified height a preset number of times, and when the Z-axis platform reaches the specified height, taking images of the Z-axis platform through the camera to obtain multiple captured images based on the Z-axis platform at the specified height; S3, obtaining the coordinate values ​​of the marker points of each captured image; S4, obtaining the compensation function of the marker points of the Z-axis platform at the specified height. This invention can effectively compensate for the offset errors of the Z-axis platform in the X-axis and Y-axis directions through the compensation function, thereby greatly reducing the movement error of the Z-axis platform through offset compensation.

Description

Technical Field

[0001] This invention relates to the field of LDI equipment accuracy technology, and in particular to a method, apparatus and storage medium for Z-axis platform verticality calibration compensation. Background Technology

[0002] LDI (Laser Direct Imaging) equipment is a laser direct imaging device based on digital micromirror arrays. It employs a sub-micron precision 3D platform, integrating high-precision 3D platforms, vision algorithms, and calibration compensation algorithms to achieve high-quality imaging. The high-precision 3D platform is the "foundation" of LDI equipment; only when the 3D platform meets the precision requirements of LDI equipment can a high-precision LDI platform be constructed.

[0003] Due to the varying thicknesses of the plates, the Z-axis platform can move vertically to meet different plate thickness requirements. Except for the Z-axis platform, which uses a servo motor, the other axes of the 3D motion platform use linear motors. Furthermore, a laser projector is used for positioning accuracy compensation, enabling the 3D motion platform to achieve the required ±1.5µm accuracy. However, although the Z-axis platform can achieve a positioning accuracy of ±1.5µm, errors inherent in the design, manufacturing, and installation processes of the 3D platform can cause slight offsets in the X and Y directions during movement. For sub-micron high-precision LDI platforms, these slight offsets can significantly affect the accuracy of the LDI equipment. Summary of the Invention

[0004] The purpose of this invention is to provide a Z-axis platform verticality calibration compensation method, device, and storage medium, which can effectively compensate for the offset errors of the Z-axis platform in the X-axis and Y-axis directions through a compensation function, thereby greatly reducing the movement error of the Z-axis platform through offset compensation.

[0005] To achieve the above objectives, this invention discloses a Z-axis platform verticality calibration and compensation method, applicable to LDI equipment. The Z-axis platform verticality calibration and compensation method includes the following steps:

[0006] S1. Place the camera above the Z-axis platform so that the Z-axis platform is always within the imaging area of ​​the camera within a preset height range. The Z-axis platform is provided with marker points.

[0007] S2. Control the Z-axis platform to move along the Z-axis direction a preset number of times so that the Z-axis platform reaches a specified height a preset number of times, and when the Z-axis platform reaches the specified height, take an image of the Z-axis platform through the camera to obtain multiple captured images based on the Z-axis platform at the specified height;

[0008] S3. Perform image analysis on each captured image to obtain the coordinate values ​​of the marker points in each captured image;

[0009] S4. Fit the coordinate values ​​of the marker points in all captured images to obtain the compensation function for the marker points of the Z-axis platform at the specified height.

[0010] Preferably, in step S2, controlling the Z-axis platform to move along the Z-axis direction a preset number of times, so that the Z-axis platform reaches a specified height a preset number of times, specifically includes:

[0011] S21. Using the specified height as the waypoint, control the Z-axis platform to move along the Z-axis direction a preset number of times;

[0012] S22. When the Z-axis platform reaches the specified height, control the Z-axis platform to stay at the specified height for a preset time.

[0013] Preferably, step S21 specifically includes:

[0014] Using the specified height as a waypoint, the Z-axis platform is controlled to randomly reciprocate a preset number of times along the Z-axis direction.

[0015] Preferably, step S21 specifically includes:

[0016] The Z-axis platform is controlled to reciprocate within a preset stroke along the Z-axis direction, and the specified height is located within the preset stroke.

[0017] Preferably, in step S2, when the Z-axis platform reaches the specified height, the camera captures images of the Z-axis platform to obtain multiple captured images based on the Z-axis platform at the specified height, specifically including:

[0018] When the Z-axis platform reaches the specified height, images are captured using the marker point of the Z-axis platform as the focal point, thereby obtaining multiple captured images based on the Z-axis platform at the specified height.

[0019] Preferably, the marker point is the center point of the Z-axis platform.

[0020] Preferably, assuming the coordinates of the marker point in the captured image are (x, y), step S3 specifically includes:

[0021] S31. Construct a linear regression function y = kx + b for the coordinates of the marker points in the captured image, where k and b are constants;

[0022] S32. Fit the coordinates (x, y) of the marker points of all captured images to the linear regression function y = kx + b, so that the value of k is K and the value of b is B.

[0023] S33. Substitute K and B into the linear regression function y = kx + b to obtain the compensation function y = Kx + B for the marker point of the Z-axis platform at the specified height.

[0024] Preferably, the preset number of times is greater than or equal to 100 times.

[0025] Accordingly, the present invention also discloses a Z-axis platform verticality calibration compensation device, applicable to LDI equipment, comprising:

[0026] The Z-axis platform can move up and down along the Z-axis direction;

[0027] A camera is positioned above a Z-axis platform so that the Z-axis platform is always within the imaging area of ​​the camera within a preset height range. The Z-axis platform is equipped with marker points.

[0028] An execution module is used to control the Z-axis platform to move along the Z-axis direction a preset number of times so that the Z-axis platform reaches a specified height a preset number of times, and when the Z-axis platform reaches the specified height, to take images of the Z-axis platform through the camera to obtain multiple captured images based on the Z-axis platform at the specified height;

[0029] The first processing module is used to perform image analysis on each captured image to obtain the coordinate values ​​of the marker points of each captured image.

[0030] The second processing module is used to fit the coordinate values ​​of the marker points of all captured images to obtain the compensation function of the marker points of the Z-axis platform at the specified height.

[0031] Accordingly, the present invention also discloses a storage medium for storing a computer program, which, when executed by a processor, implements the Z-axis platform verticality calibration compensation method as described above.

[0032] Compared with the prior art, the present invention obtains the coordinate values ​​of the marker points of the Z-axis platform at multiple heights by moving the Z-axis platform to a specified height multiple times. Then, it uses the coordinate values ​​of the marker points at the same height obtained multiple times to fit and obtain the compensation function of the marker point of the Z-axis platform at the specified height. Since the coordinate value of the marker point of each Z-axis platform is actually a piecewise linear function, fitting multiple piecewise linear functions and performing linear compensation to obtain the compensation function of the marker point of the Z-axis platform at the specified height can effectively compensate for the offset error of the Z-axis platform in the X-axis and Y-axis directions through the compensation function, thereby greatly reducing the movement error of the Z-axis platform through offset compensation. Attached Figure Description

[0033] Figure 1 This is a flowchart of the Z-axis platform verticality calibration and compensation method of the present invention;

[0034] Figure 2 This is a statistical chart of the offset of the Z-axis platform in the X and Y directions at different heights for LDI equipment that does not use the Z-axis platform verticality calibration compensation method of the present invention;

[0035] Figure 3 This is a statistical chart showing the offset of the Z-axis platform in the X and Y directions at different heights after the LDI equipment adopts the Z-axis platform verticality calibration and compensation method of the present invention. Detailed Implementation

[0036] To illustrate the technical content, structural features, objectives, and effects of the present invention in detail, the following description is provided in conjunction with the embodiments and accompanying drawings.

[0037] Please see Figure 1 As shown in this embodiment, a Z-axis platform verticality calibration and compensation method is applicable to LDI equipment. The Z-axis platform verticality calibration and compensation method includes the following steps:

[0038] S1. Place the camera above the Z-axis platform so that the Z-axis platform always falls within the imaging area of ​​the camera within a preset height range. The Z-axis platform is equipped with marker points.

[0039] S2. Control the Z-axis platform to move along the Z-axis direction a preset number of times so that the Z-axis platform reaches a specified height a preset number of times, and when the Z-axis platform reaches the specified height, take images of the Z-axis platform through the camera to obtain multiple captured images based on the Z-axis platform at the specified height.

[0040] Preferably, the preset number of times is greater than or equal to 100, which involves repeatedly taking pictures of the Z-axis platform when it reaches the preset height to ensure the fitting effect during subsequent fitting processing.

[0041] S3. Perform image analysis on each captured image to obtain the coordinate values ​​of the marker points in each captured image.

[0042] S4. Fit the coordinate values ​​of the marker points in all captured images to obtain the compensation function for the marker points of the Z-axis platform at the specified height.

[0043] Preferably, in step S2, controlling the Z-axis platform to move along the Z-axis direction a preset number of times, so that the Z-axis platform reaches a specified height a preset number of times, specifically includes:

[0044] S21. Using the specified height as the waypoint, control the Z-axis platform to move along the Z-axis direction a preset number of times.

[0045] S22. When the Z-axis platform reaches the specified height, control the Z-axis platform to stay at the specified height for a preset time.

[0046] Preferably, step S21 specifically includes:

[0047] Using the specified height as a waypoint, the Z-axis platform is controlled to randomly reciprocate a preset number of times along the Z-axis direction.

[0048] In other embodiments, preferably, step S21 specifically includes:

[0049] The Z-axis platform is controlled to reciprocate within a preset stroke along the Z-axis direction, and the specified height is located within the preset stroke.

[0050] Please see Figure 1 As shown, preferably, in step S2, when the Z-axis platform reaches the specified height, the camera captures images of the Z-axis platform to obtain multiple captured images based on the Z-axis platform at the specified height, specifically including:

[0051] When the Z-axis platform reaches the specified height, images are captured using the marker point of the Z-axis platform as the focal point, thereby obtaining multiple captured images based on the Z-axis platform at the specified height.

[0052] Preferably, the marker point is the center point of the Z-axis platform.

[0053] Preferably, assuming the coordinates of the marker point in the captured image are (x, y), step S3 specifically includes:

[0054] S31. Construct a linear regression function y = kx + b for the coordinates of the marker points in the captured image, where k and b are constants.

[0055] S32. Fit the coordinates (x, y) of all captured image markers to the linear regression function y = kx + b, and calculate the value of k as K and the value of b as B.

[0056] S33. Substitute K and B into the linear regression function y = kx + b to obtain the compensation function y = Kx + B for the marker point of the Z-axis platform at the specified height.

[0057] It is understandable that setting the marker point as the center point of the Z-axis platform ensures that the focus of the captured image obtained by the camera is the center point of the Z-axis platform, effectively reducing the impact of external factors such as the shape and flatness of the Z-axis platform on the compensation effect.

[0058] In practical use, the coordinates (x, y) of all the marker points in the captured images can be entered into an Excel spreadsheet, and the compensation function can be obtained by fitting using Excel functions, which will not be elaborated here.

[0059] Please see Figures 1-3 It is worth noting that this embodiment uses the calculation of the compensation function of the marker point of the Z-axis platform at a single specified height as an example to illustrate the process of this embodiment. In order to meet the compensation of the Z-axis platform of the LDI device in different height ranges, the compensation function of the Z-axis platform at different specified heights can be calculated separately.

[0060] Figure 2 The diagram illustrates how, with a height step of 0.1 mm between adjacent specified heights, the compensation function for each specified height is solved to obtain K and B for multiple compensation functions in fixed segments. These multiple fixed-segment compensation functions are then applied to LDI exposure equipment software, and the deviations of the Z-axis in the X and Y directions at different heights are measured again. Figure 3 The test results of the LDI device using the compensation function of the marker point of the Z-axis platform at the specified height obtained through this embodiment are shown. Figure 3 As can be seen from the offsets in the X and Y directions, there is a significant optimization in both directions after compensation using a piecewise linear regression mathematical model.

[0061] Specifically, in Figure 2 In the first case, the deviation in the X direction was 16.97 μm and the deviation in the Y direction was 7.70 μm before processing; while in the second case... Figure 3 In the middle: after compensation, the maximum offset in the X direction is only 4um and the maximum offset in the Y direction is 4um. Therefore, the compensation function of the marker point of the Z-axis platform at the specified height obtained by this embodiment can effectively improve the positioning accuracy of the three-dimensional motion platform.

[0062] In addition, based on the accuracy requirements of the submicron-level high-precision LDI platform, the height step size can also be set to 0.2mm or 0.3mm, or other height step sizes less than 0.1mm, which will not be elaborated here.

[0063] Accordingly, the present invention also discloses a Z-axis platform verticality calibration compensation device, applicable to LDI equipment, comprising:

[0064] The Z-axis platform can move up and down along the Z-axis direction;

[0065] A camera is positioned above a Z-axis platform so that the Z-axis platform is always within the imaging area of ​​the camera within a preset height range. The Z-axis platform is equipped with marker points.

[0066] An execution module is used to control the Z-axis platform to move along the Z-axis direction a preset number of times so that the Z-axis platform reaches a specified height a preset number of times, and when the Z-axis platform reaches the specified height, to take images of the Z-axis platform through the camera to obtain multiple captured images based on the Z-axis platform at the specified height;

[0067] The first processing module is used to perform image analysis on each captured image to obtain the coordinate values ​​of the marker points of each captured image.

[0068] The second processing module is used to fit the coordinate values ​​of the marker points of all captured images to obtain the compensation function of the marker points of the Z-axis platform at the specified height.

[0069] Accordingly, the present invention also discloses a storage medium for storing a computer program, which, when executed by a processor, implements the Z-axis platform verticality calibration compensation method as described above.

[0070] Combination Figures 1-3 This invention obtains the coordinate values ​​of multiple marker points of the Z-axis platform at the same height by moving the Z-axis platform multiple times to a specified height. Then, it uses the coordinate values ​​of the marker points at the same height obtained multiple times to fit and obtain a compensation function for the marker points of the Z-axis platform at the specified height. Since the coordinate value of each marker point of the Z-axis platform is actually a piecewise linear function, fitting multiple piecewise linear functions and performing linear compensation to obtain the compensation function for the marker points of the Z-axis platform at the specified height can effectively compensate for the offset errors of the Z-axis platform in the X-axis and Y-axis directions, thereby greatly reducing the movement error of the Z-axis platform through offset compensation.

[0071] The above-disclosed embodiments are merely preferred embodiments of the present invention and should not be construed as limiting the scope of the present invention. Therefore, any equivalent variations made in accordance with the claims of the present invention are still within the scope of the present invention.

Claims

1. A method for calibrating and compensating the verticality of a Z-axis platform, applicable to LDI equipment, characterized in that, The Z-axis platform verticality calibration and compensation method includes the following steps: The camera is placed above the Z-axis platform so that the Z-axis platform is always within the imaging area of ​​the camera within a preset height range. The Z-axis platform is equipped with marker points. The Z-axis platform is controlled to move along the Z-axis direction a preset number of times so that the Z-axis platform reaches a specified height a preset number of times. When the Z-axis platform reaches the specified height, the camera takes images of the Z-axis platform to obtain multiple captured images based on the Z-axis platform at the specified height. Image analysis is performed on each captured image to obtain the coordinate values ​​of the marker points in each captured image; The coordinate values ​​of the marker points in all captured images are fitted to obtain a compensation function for the marker points of the Z-axis platform at the specified height. The process of controlling the Z-axis platform to move along the Z-axis direction a preset number of times to reach a specified height a preset number of times, and capturing images of the Z-axis platform by the camera when the Z-axis platform reaches the specified height to obtain multiple captured images based on the Z-axis platform at the specified height, specifically includes: Using the specified height as a waypoint, control the Z-axis platform to move along the Z-axis direction a preset number of times; When the Z-axis platform reaches the specified height, the Z-axis platform is controlled to stay at the specified height for a preset time; The step of controlling the Z-axis platform to move along the Z-axis direction a preset number of times, using the specified height as a waypoint, specifically includes: The Z-axis platform is controlled to reciprocate within a preset stroke along the Z-axis direction, and the specified height is located within the preset stroke. The marker point is the center point of the Z-axis platform; Let the coordinates of the marker points in the captured images be (x, y). The step of performing image analysis on each captured image to obtain the coordinates of the marker points in each captured image specifically includes: Construct a linear regression function y=kx+b for the coordinates of the marker points in the captured image, where k and b are constants; The coordinates (x, y) of all captured image markers are fitted to the linear regression function y = kx + b, so that the value of k is K and the value of b is B. Substituting K and B into the linear regression function y=kx+b, we obtain the compensation function y=Kx+B for the marker point of the Z-axis platform at the specified height.

2. The Z-axis platform verticality calibration and compensation method as described in claim 1, characterized in that, The step of controlling the Z-axis platform to move along the Z-axis direction a preset number of times, using the specified height as a waypoint, specifically includes: Using the specified height as a waypoint, the Z-axis platform is controlled to randomly reciprocate a preset number of times along the Z-axis direction.

3. The Z-axis platform verticality calibration and compensation method as described in claim 1, characterized in that, The process of controlling the Z-axis platform to move along the Z-axis direction a preset number of times, so that the Z-axis platform reaches a specified height a preset number of times, and when the Z-axis platform reaches the specified height, taking images of the Z-axis platform through the camera to obtain multiple captured images based on the Z-axis platform at the specified height, specifically includes: When the Z-axis platform reaches the specified height, images are captured using the marker point of the Z-axis platform as the focal point, thereby obtaining multiple captured images based on the Z-axis platform at the specified height.

4. The Z-axis platform verticality calibration and compensation method as described in claim 1, characterized in that, The preset number of times is greater than or equal to 100.

5. A storage medium for storing computer programs, characterized in that: When the program is executed by the processor, it implements the Z-axis platform verticality calibration compensation method as described in any one of claims 1 to 4.

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