Coaxial alignment device and coaxial alignment method

Abstract

The invention discloses a coaxial alignment device and a coaxial alignment method. The coaxial alignment device comprises a bearing, an adjusting mirror bracket, a display plate to be coaxially aligned, a microscopic system and a platform, an outer ring of the bearing is connected with the platform, an inner ring of the bearing is connected with the adjusting mirror bracket, and the adjusting mirror bracket is located above the bearing; the center of the display plate is provided with a center mark, and the display plate is connected to the center of the adjusting mirror bracket; and the microscopic system is erected above the adjusting mirror bracket and is used for observing the motion trail of the center mark of the display plate in the adjusting mirror bracket. According to the coaxial alignment device and the coaxial alignment method, the high precision of coaxial alignment can be met, meanwhile, the workload of adjustment and calibration personnel can be greatly reduced, the complexity and the cost of the whole mechanical structure are reduced, the external influence degree of the whole mechanical structure is reduced, and the stability is improved.

Description

Technical Field

[0001] The invention relates to the technical field of optical axis alignment, in particular to a coaxial alignment device and a coaxial alignment method. Background Art

[0002] Coaxial alignment is the process of adjusting the central axes of two or more components to completely coincide in optical systems, mechanical systems, or other technical fields. This process is critical to ensuring system performance. Coaxial alignment provides high-precision alignment solutions for various applications such as lithography in semiconductor manufacturing, laser communications, precision mechanical assembly, and optical systems. A complete coaxial alignment system usually relies on a precision measurement and control system, which includes the use of optical sensors, position encoders, servo motors, and computer-controlled mechanical stages to achieve and maintain the alignment state. In order to achieve the required accuracy, these systems usually require complex designs and precise calibration procedures. Therefore, high-precision coaxial alignment systems are often costly and cumbersome. When the equipment is in operation for a long time, the mechanical structure will also produce slight displacements, affecting the alignment state. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a coaxial alignment device and a coaxial alignment method in view of the deficiencies of the above-mentioned prior art. The coaxial alignment device and the coaxial alignment method can greatly reduce the workload of the adjustment personnel while meeting the high precision of the coaxial alignment, reduce the complexity and cost of the overall mechanical structure, reduce the degree of its being affected by the outside world, and improve stability.

[0004] In order to achieve the above technical objectives, the technical solution adopted by the present invention is:

[0005] A coaxial alignment device comprises a bearing, an adjustment mirror frame, a display plate to be coaxially aligned, a microscope system and a platform;

[0006] The outer ring of the bearing is connected to the platform, the inner ring of the bearing is connected to the adjustment mirror frame, and the adjustment mirror frame is located above the bearing;

[0007] A center mark is provided at the center of the display plate, and the display plate is connected to the center of the adjustment frame;

[0008] The microscope system is mounted above the adjusting mirror frame and is used to observe the movement track of the center mark of the display plate in the adjusting mirror frame.

[0009] As a further improved technical solution of the present invention, there are multiple adjusting mirror frames and display boards to be coaxially aligned, the center of each adjusting mirror frame is connected to a display board, and the multiple adjusting mirror frames are connected in sequence from bottom to top.

[0010] As a further improved technical solution of the present invention, there are two adjusting mirror frames, respectively denoted as adjusting mirror frame one and adjusting mirror frame two; there are two display boards, respectively denoted as display board one and display board two; display board one is fixedly connected at the center of board seat one, and board seat one is threadedly connected in the center hole of adjusting mirror frame one; display board two is fixedly connected at the center of board seat two, and board seat two is threadedly connected in the center hole of adjusting mirror frame two; the inner ring of the bearing is connected to the connecting disk, the connecting disk is connected to the adjusting mirror frame one through the connecting plate one, the adjusting mirror frame two is connected to the connecting plate one through the connecting plate two, the adjusting mirror frame one is located above the bearing, and the adjusting mirror frame two is located above the adjusting mirror frame one.

[0011] As a further improved technical solution of the present invention, the display plate 1 and the display plate 2 are both bright field 90° cross line differentiation plates, and the plate holder 1 and the plate holder 2 are both differentiation plate holders;

[0012] There is a through hole in the center of the differentiation plate seat, and a circular groove at the bottom for placing the bright field 90° cross-line differentiation plate. The center of the circular groove is the center of the through hole, and the bright field 90° cross-line differentiation plate is fixedly connected in the circular groove by silicone.

[0013] As a further improved technical solution of the present invention, the second connecting plate is connected to the Z-axis guide rail platform, and the second adjusting mirror frame is connected to a slider in the Z-axis guide rail platform.

[0014] As a further improved technical solution of the present invention, the platform adopts an XYZ three-axis cross-guide manual displacement platform, the bottom of the platform is connected to the air floating platform through a base plate, the adjustment mirror frame adopts a four-dimensional adjustment mirror frame, the microscope system adopts a continuous magnification microscope system, and the bearing adopts a cross roller bearing.

[0015] As a further improved technical solution of the present invention, the outer ring of the bearing is connected to the platform through a bearing fixing plate and bolts, the inner ring of the bearing is threadedly connected to the connecting plate, the bottom of the connecting plate one is connected to the connecting plate by bolts, the top of the connecting plate one is connected to the adjusting mirror frame one by bolts, the bottom of the connecting plate two is connected to the Z-axis guide platform by bolts, and the adjusting mirror frame two is connected to a slider in the Z-axis guide platform by bolts.

[0016] In order to achieve the above technical purpose, another technical solution adopted by the present invention is:

[0017] A coaxial alignment method comprises the following steps:

[0018] Step 1, fix the display plate 1 with the center mark in the center hole of the adjustment frame 1, and fix the display plate 2 with the center mark in the center hole of the adjustment frame 2;

[0019] Step 2: Build the upper microscope system;

[0020] Step 3, build a platform below the microscope system, connect the outer ring of the bearing to the platform, connect the inner ring of the bearing to the adjustment frame 1, and the adjustment frame 1 is located above the bearing;

[0021] Step 4, open the camera software in the microscope system, adjust the distance between the microscope system and the display board 1 to find the best imaging position of the display board 1 in the camera software, adjust the x and y axis directions on the frame 1, and then move the center mark of the display board 1 to the center of the target surface of the camera;

[0022] Step 5: Rotate the inner ring of the bearing and observe the motion trajectory of the center mark of the display board 1 through the camera software. The center mark of the display board 1 rotates in a regular circle, and the center of the circle is recorded as the fixed point;

[0023] Step 6: Continue to rotate the inner ring of the bearing, and adjust the x-axis and y-axis directions on the mirror frame 1 at the same time, so that the center mark of the display board 1 is close to the fixed point;

[0024] Step 7, using the inner ring of the bearing to rotate the display board 1 360°, and evenly intercepting ten images of the display board 1 within 360°;

[0025] Step 8: extract features from the ten images captured by the camera software, calculate the coordinate position of the center mark of the display board 1, obtain the motion trajectory of the center mark of the display board 1, and calculate the radius of the motion trajectory of the center mark moving around the fixed point;

[0026] Step 9, repeat steps 6-8 until the radius of the center mark motion trajectory of the display plate 1 is less than a preset value, and then execute step 10;

[0027] Step 10, connecting the second connecting plate to the first connecting plate, connecting the second connecting plate to the second adjusting frame, the second adjusting frame being located above the first adjusting frame, and ensuring that the second adjusting frame is arranged parallel to the first adjusting frame;

[0028] Step 11, adjust the distance between the microscope system and the second display board to find the best imaging position of the second display board in the camera software, adjust the x and y axis directions on the second mirror frame, and move the center mark of the second display board to the center of the target surface of the camera;

[0029] Step 12, rotate the inner ring of the bearing, and observe the motion trajectory of the center mark of the second display board through the camera software. The center mark of the second display board rotates in a regular circle, and the center of the circle is recorded as the fixed point;

[0030] Step 13, continue to rotate the inner ring of the bearing, and adjust the x and y axis directions on the second mirror frame at the same time, so that the center mark of the second display board is close to the fixed point;

[0031] Step 14, using the inner ring of the bearing to rotate the display board 2 360°, and evenly intercepting ten images of the display board 2 within 360°;

[0032] Step 15, extract features from the ten images captured by the camera software, calculate the coordinate position of the center mark of the second display board, obtain the motion trajectory of the center mark of the second display board, and calculate the radius of the motion trajectory of the center mark moving around the fixed point;

[0033] Step 16: Repeat steps 13-15 until the radius of the motion trajectory of the center mark of the second display board is smaller than a preset value, thereby completing the coaxial alignment of the first display board and the second display board.

[0034] As a further improved technical solution of the present invention, the display plate 1 and the display plate 2 are both bright field 90° cross-line differentiation plates, the adjustment frame 1 and the adjustment frame 2 are both four-dimensional adjustment frames, and the microscope system adopts a continuous zoom microscope system;

[0035] The step 1 is specifically as follows:

[0036] Connect a bright field 90° cross-line differentiation plate to the center of a differentiation plate holder, and the differentiation plate holder is connected to the center hole of the adjustment mirror frame;

[0037] Connect another bright field 90° cross-line differentiation plate to the center of another differentiation plate holder, and the differentiation plate holder is connected to the center hole of the second adjustment mirror frame;

[0038] The step 3 is specifically as follows:

[0039] An XYZ three-axis cross-guide manual displacement platform is built below the continuous zoom microscope system, the outer ring of the bearing is connected to the XYZ three-axis cross-guide manual displacement platform through a bearing fixing plate, the inner ring of the bearing is connected to a connecting plate, the connecting plate is connected to an adjusting mirror frame one through a connecting plate one, and the adjusting mirror frame one is located above the bearing;

[0040] The step 4 is specifically as follows:

[0041] Open the camera software in the zoom microscope system, adjust the distance between the zoom microscope system and the bright field 90° crosshair differentiation plate in the adjustment frame 1 to find the best imaging position of the bright field 90° crosshair differentiation plate in the camera software, adjust the x and y axis directions on the adjustment frame 1, and then move the center of the cross mark of the bright field 90° crosshair differentiation plate therein to the center of the target surface of the camera;

[0042] The step 5 is specifically as follows:

[0043] Rotate the inner ring of the bearing and observe the motion trajectory of the cross mark on the 90° cross-line differentiation plate of the bright field in the frame through the camera software. The center of the cross mark rotates in a regular circle, and the center of the circle is recorded as the fixed point;

[0044] Rotate the inner ring of the bearing and adjust the x and y axis directions on the first mirror frame so that the center of the cross mark on the bright field 90° crosshair differentiation plate is close to the fixed point;

[0045] Use the zoom function of the zoom microscope system to adjust the distance between the zoom microscope system and the bright field 90° crosshair differentiation plate in the adjustment frame 1 again to find the best imaging position of the bright field 90° crosshair differentiation plate in the camera software. At this time, the image on the camera target surface becomes larger. Repeatedly rotate the inner ring of the bearing and adjust the x and y axis directions on the adjustment frame 1 so that the center of the cross mark of the bright field 90° crosshair differentiation plate is close to the fixed point.

[0046] The step 6 is specifically as follows:

[0047] Continue to rotate the inner ring of the bearing, and adjust the x and y axis directions on the mirror frame 1 at the same time, so that the center of the cross mark on the bright field 90° crosshair differentiation plate is close to the fixed point;

[0048] The step 7 is specifically as follows:

[0049] The bright field 90° cross-line differentiation plate in the adjustment frame 1 is rotated 360° by using the inner ring of the bearing, and ten images of the bright field 90° cross-line differentiation plate are evenly intercepted within 360°;

[0050] The step 8 is specifically as follows:

[0051] Perform feature extraction on the ten images captured by the camera software, calculate the coordinate position of the center of the cross mark of the bright field 90° cross-line differentiation plate in the image, obtain the motion trajectory deduction of the center of the cross mark of the bright field 90° cross-line differentiation plate, and calculate the radius of the motion trajectory of the center point moving around the fixed point;

[0052] The step 9 is specifically as follows:

[0053] Repeat steps 6-8 until the radius of the central motion trajectory of the cross mark of the bright field 90° cross line differentiation plate in the image is less than a preset value, and then execute step 10;

[0054] The step 11 is specifically as follows:

[0055] Adjust the distance between the zoom microscope system and the bright field 90° crosshair differentiation plate in the second adjustment mirror frame to find the best imaging position of the bright field 90° crosshair differentiation plate in the camera software, adjust the x and y axis directions on the second adjustment mirror frame, and then move the center of the cross mark of the bright field 90° crosshair differentiation plate to the center of the target surface of the camera;

[0056] The step 12 is specifically as follows:

[0057] Rotate the inner ring of the bearing and observe the movement trajectory of the cross mark on the 90° cross-line differentiation plate of the bright field in the second frame through the camera software. The center of the cross mark rotates in a regular circle, and the center of the circle is recorded as the fixed point;

[0058] Rotate the inner ring of the bearing and adjust the x and y axis directions on the second mirror frame so that the center of the cross mark on the bright field 90° crosshair differentiation plate is close to the fixed point;

[0059] Use the zoom function of the zoom microscope system to adjust the distance between the zoom microscope system and the bright field 90° crosshair differentiation plate in the second adjustment mirror frame again to find the best imaging position of the bright field 90° crosshair differentiation plate in the camera software. At this time, the image on the camera target surface becomes larger. Repeatedly rotate the inner ring of the bearing and adjust the x and y axis directions on the second adjustment mirror frame so that the center of the cross mark of the bright field 90° crosshair differentiation plate is close to the fixed point.

[0060] The step 13 is specifically as follows:

[0061] Continue to rotate the inner ring of the bearing, and adjust the x and y axis directions on the second mirror frame at the same time, so that the center of the cross mark on the bright field 90° crosshair differentiation plate is close to the fixed point;

[0062] The step 14 is specifically as follows:

[0063] The bright field 90° cross-line differentiation plate in the second adjustment mirror frame is rotated 360° by using the inner ring of the bearing, and ten images of the bright field 90° cross-line differentiation plate are evenly intercepted within 360°;

[0064] The step 15 is specifically as follows:

[0065] Perform feature extraction on the ten images captured by the camera software, calculate the coordinate position of the center of the cross mark of the bright field 90° cross-line differentiation plate in the image, obtain the motion trajectory deduction of the center of the cross mark of the bright field 90° cross-line differentiation plate, and calculate the radius of the motion trajectory of the center point moving around the fixed point;

[0066] The step 16 is specifically as follows:

[0067] Repeat steps 13-15 until the radius of the central motion trajectory of the cross mark of the bright field 90° cross-line differentiation plate in the image is smaller than a preset value, thereby completing the coaxial alignment of the two bright field 90° cross-line differentiation plates.

[0068] The beneficial effects of the present invention are:

[0069] In order to solve the above problems, the present invention proposes a coaxial alignment device for observing the rotation of bearings using a microscope system. The core of this technology is to use a camera with smaller pixels to capture the center of the bearing and adjust the microcomputer for precise adjustment at the same time.

[0070] When using the bearing coaxial alignment device, the bright field 90° crosshair differentiation plate fixed at the center of the four-dimensional precision mirror frame can be observed through the microscope system. The adjustment screws in the XY axis direction on the four-dimensional mirror frame can be directly used to gradually deduce the position of the "fixed point" in continuous manual rotation and keep approaching until the center position of the plane where the cross mark is located coincides with the center of the bearing. The entire device is based on the bearing center from top to bottom, with good consistency and stability. During use, the height can be adjusted according to the actual usage scenario.

[0071] Such a device layout is not only simple, but also clear whether the upper and lower planes are aligned with the center of the bearing. When the whole device is used, it solves the problem of finding the benchmark for coaxial alignment. The confirmed benchmark is directly used for debugging. The whole adjustment process is simple and easy to operate. The synchronization during the coaxial debugging process is good, and immediate feedback can be obtained. The interval between the rotation center of the bearing and the center position of the cross mark can be intuitively observed, which makes it easier to adjust to the accuracy requirements. This device can shorten the alignment time to one-third of the original time, and at the same time improve the alignment accuracy to the sub-micron level, significantly improving the integrity and reliability of the optical system.

[0072] Because this device uses the bearing for alignment, the entire device always uses the center of the bearing as the reference, avoiding the difficulty in finding the reference in the previous alignment system. The accuracy of the bearing in this device is the alignment accuracy. You can use a micrometer in advance, place the probe on the outer or inner ring of the bearing, install the bearing on a rotating platform, rotate the bearing, and observe the change in the probe reading to reflect the accuracy of the radial jump. This method can be selected according to actual use needs, which is more flexible.

[0073] The display plate in the device is not limited to a bright field 90° cross-line differentiation plate, but can be any object that can be displayed and to be coaxially aligned, and the center of the object has been marked. The coaxial alignment device and coaxial alignment method can greatly reduce the workload of the adjustment personnel, reduce the complexity and cost of the overall mechanical structure, reduce the degree of its influence by the outside world, and improve stability while meeting the high precision of coaxial alignment. BRIEF DESCRIPTION OF THE DRAWINGS

[0074] Figure 1 Schematic diagram of the differentiation plate base structure.

[0075] Figure 2 It is a structural schematic diagram of the cross-line dividing plate installed in the groove at the bottom of the dividing plate base.

[0076] Figure 3 This is the fixed installation diagram of the XYZ three-axis cross-guide type manual displacement platform.

[0077] Figure 4 This is a schematic diagram of the installation of bearings and connecting plates.

[0078] Figure 5 This is a schematic diagram of the installation of the lower side adjustment mirror frame.

[0079] Figure 6-Figure 8 This is a schematic diagram showing the installation of the entire device.

[0080] Fig. 9 A schematic diagram is used to illustrate the principle of device alignment.

[0081] Fig.10 This is the image displayed when the CCD camera in the microscope system observes the cross-sectional plate.

[0082] Fig.11 Capture the 360° cross-reticle motion trajectory diagram for the camera.

[0083] Fig.12 Complete the schematic for device alignment accuracy. DETAILED DESCRIPTION

[0084] The specific embodiments of the present invention are further described below according to the accompanying drawings:

[0085] A coaxial alignment device comprises a bearing 7, a plurality of adjustment mirror frames, a plurality of display boards to be coaxially aligned, a microscope system 14 and a platform. The center of each adjustment mirror frame is connected to a display board, and the plurality of adjustment mirror frames are connected in sequence from bottom to top. A center mark is provided at the center of the display board, and the display board is connected to the center of the adjustment mirror frame.

[0086] Specifically, there are two adjustment frames, which are respectively denoted as adjustment frame 1 10 and adjustment frame 2 12. Adjustment frame 1 10 and adjustment frame 2 12 are four-dimensional adjustment frames. There are two display boards, which are respectively denoted as display board 1 and display board 2. Both display board 1 and display board 2 are as follows Figure 2The bright field 90° cross-line differentiation plate 1 shown. One bright field 90° cross-line differentiation plate 1 is fixedly connected to the center of a differentiation plate seat 2, and the differentiation plate seat 2 is threadedly connected to the center hole of the adjustment frame 10; another bright field 90° cross-line differentiation plate 1 is fixedly connected to the center of another differentiation plate seat 2, and the differentiation plate seat 2 is threadedly connected to the center hole of the adjustment frame 2 12. The outer ring of the bearing 7 is connected to the platform, the inner ring of the bearing 7 is connected to the connecting plate 8, the connecting plate 8 is connected to the adjustment frame 10 through the connecting plate 19, and the adjustment frame 2 12 is connected to the connecting plate 19 through the connecting plate 2 11. The adjustment frame 10 is located above the bearing 7, and the adjustment frame 2 12 is located above the adjustment frame 10. The adjustment frame 10 and the adjustment frame 2 12 are arranged in parallel, so that the camera observation is more convenient and clearer.

[0087] The microscope system 14 is mounted above the adjusting mirror frame 1 10 and the adjusting mirror frame 2 12 , and is used to observe the movement trajectory of the crosshair center of the bright field 90° crosshair differentiation plate 1 in the adjusting mirror frame 1 10 and the adjusting mirror frame 2 12 .

[0088] Specifically, the display plate 1 and the display plate 2 are not limited to the bright field 90° cross-line differentiation plate 1, and can be any object that can be displayed, and the center of the object has been marked.

[0089] like Figure 1-2 As shown, the differentiation plate seat 2 has a through hole in the center, and a circular groove at the bottom for placing the bright field 90° cross-line differentiation plate 1. The center of the circular groove is the center of the through hole, and the bright field 90° cross-line differentiation plate 1 is fixedly connected in the circular groove by silicone.

[0090] Specifically, Figure 6-8 As shown, the connecting plate 2 11 is connected to the Z-axis guide platform 13, and the adjusting mirror frame 2 12 is connected to the slider in the Z-axis guide platform 13. The Z-axis guide platform 13 is used to drive the adjusting mirror frame 2 12 to move up and down, so as to adjust the distance between the adjusting mirror frame 1 10 and the adjusting mirror frame 2 12 according to the demand.

[0091] Specifically, Figure 3-5 As shown, the platform connected to the outer ring of the bearing 7 adopts an XYZ three-axis cross-guide type manual displacement platform 5, the bottom of the XYZ three-axis cross-guide type manual displacement platform 5 is connected to the air floating platform 3 through a base plate 4, the adjustment frame 1 10 and the adjustment frame 2 12 adopt four-dimensional adjustment frames, the microscope system 14 adopts a continuous zoom microscope system, and the bearing 7 adopts a crossed roller bearing.

[0092] Specifically, the outer ring of the bearing 7 is connected to the XYZ three-axis cross-guide type manual displacement platform 5 through the bearing fixing plate 6 and bolts, the inner ring of the bearing 7 is threadedly connected to the connecting plate 8, the bottom of the connecting plate 1 9 is connected to the connecting plate 8 through bolts, the top of the connecting plate 1 9 is connected to the adjusting mirror frame 1 10 through bolts, the bottom of the connecting plate 2 11 is connected to the Z-axis guide platform 13 through bolts, and the adjusting mirror frame 2 12 is connected to the slider in the Z-axis guide platform 13 through bolts. The Z-axis guide platform 13 can adjust the height of the adjusting mirror frame 2 12.

[0093] The alignment process of the above coaxial alignment device is:

[0094] First, two bright field 90° cross-line differentiation plates 11 can be fixed at the center of the differentiation plate holder with silicone, and irradiated with warm light and cured for 3 hours, during which time, ensure that they will not fall off and have no warping.

[0095] Secondly, you can build Fig. 9 The upper continuous zoom microscope system 14 shown above uses an LED light source 16 as the light source, and a CCD camera 15 uses a 2 / 3" CMOS, with a resolution of 2448X2048, and a pixel size of 3.45X3.45 microns. The pixel calculation process is: calculate the pixel sizes of the long side and the short side respectively.

[0096]

[0097] During the installation process, the tilt needs to be adjusted to ensure that the light can pass through the objective lens and illuminate the object surface below vertically, so as to achieve a better imaging effect.

[0098] Then build as Figure 3-8 The object to be observed below is shown in the figure. The entire installation and use process needs to be completed on the air-floating platform 3 to reduce the influence of external factors. After tightening the tooling base plate 4 on the air-floating platform 3, a cross-guide type X, Y axis direction and a cross-guide type manual displacement platform Z axis direction, that is, an XYZ three-axis cross-guide type manual displacement platform 5, is fixed on it, and a bearing fixing plate 6 is placed and fixed. A high-precision cross roller bearing is placed and fixed on the bearing fixing plate 6. The connecting plate 8 is threadedly connected to the inner ring of the bearing 7. After fixing two connecting plates 9 on the connecting plate 8, the adjusting frame 10 is connected. A differentiation plate seat with a cross-graticule plate is screwed to the center of the adjusting frame 10. At this time, the CCD camera 15 is turned on, the LED light source 16 is turned on, the height of the microscope system 14 is adjusted, and the best imaging position is found. The x and y axis directions on the adjusting frame 10 are manually adjusted to move the center of the cross mark to the center of the target surface of the camera, as shown in FIG. Fig.10 , so as to avoid the fixed point from moving out of the target surface due to excessive position deviation when rotating the bearing 7.

[0099] At this time, start to rotate the connecting disk 8 continuously to find the motion trajectory. It can be found that the center of the cross mark rotates in a regular circle about the "fixed point" of the bearing 7 (the center of the bearing 7). Then continue to adjust the directions of the x and y axes on the adjusting frame 10. The center of the cross mark keeps getting closer to the fixed point. Repeat the rotation of the connecting disk 8 and adjust the adjusting frame 10 until the naked eye cannot visually observe obvious changes. At this time, use the zoom of the variable magnification microscope system 14, adjust the height of the microscope system 14 again, and find the best imaging surface. At this time, the image on the target surface of the camera becomes larger. Repeat the rotation of the connecting disk 8 and adjust the adjusting frame 10 to bring the center of the cross mark closer to the center of the bearing 7 again. During use, you can also use the camera's own magnification function to observe the pixel-level movement according to the camera pixel size calculated in advance. Then use the high-precision crossed roller bearing to rotate one circle, evenly rotate 360° to capture ten photos, extract features, and calculate the center pixel position of the cross mark. You can get a motion trajectory deduction (such as Fig.11 As shown in the figure, the radius of the motion trajectory around the fixed point (i.e., the deviation from the center of the bearing 7) is calculated, and the accuracy can be verified and the coordinate position of the fixed point can be calculated. Then, the connection plate 8 is rotated repeatedly and the adjustment frame 10 is adjusted to bring the center of the cross mark closer to the center of the bearing 7 again, and then the bearing is rotated 360° evenly to intercept ten photos, extract features, calculate the current cross mark center pixel position and the radius of the motion trajectory around the fixed point; repeat the above content until the radius is less than the preset value, complete the adjustment and improve the accuracy.

[0100] After adjusting the lower side, install the second connecting plate 11, install another calibration plate holder with a cross mark on the second adjusting mirror frame 12, install the second adjusting mirror frame 12 and the lower adjusting mirror frame 10 in parallel, raise the position of the zoom microscope system 14, find the best imaging plane, that is, see the plate with the cross mark clearly, and then start the same calibration method as the lower side, rotate and adjust, then zoom in and observe the adjustment, capture the picture for calculation and adjustment verification, and adjust the alignment accuracy to the minimum radius of the center movement trajectory of the cross mark, that is, the radius is less than the preset value, that is, when the limit accuracy of the device is reached (such as Fig.12 ), the accuracy of the center alignment of the upper and lower cross cursors is the coaxial alignment accuracy, and the device can now achieve sub-micron accuracy.

[0101] For this device, it is possible to further improve the coaxial alignment accuracy. Replacing the working surfaces of the two four-dimensional adjustment mirror frames with a small air-floating platform 3 can improve stability and facilitate the debugging process. You can also choose a bearing 7 with a smaller radial jump. Replace the camera with a camera with a higher resolution and smaller pixels to improve the accuracy of pixel-level adjustment, thereby improving the stepping accuracy, improving the tooling production process of this device, better matching of parts, and also improving stability and accuracy. For sub-micron level alignment, this device can already meet the needs. At the same time, this device is a relatively low-cost instrument and can be an ideal choice for coaxial alignment.

[0102] The microscope system 14 of this embodiment adopts a continuous zoom straight-tube video microscope system, including an LED light source 16, a lens, a beam splitter, an objective lens, a tube lens, and a CCD camera 15. The system uses coaxial light illumination, which is more uniform in the field of view. The continuous zoom lens adopts a parallel light path design. The system adopts an infinite optical system, and an additional CCD camera 15 can be used to further magnify the image without affecting the optical performance. The device adopts a continuous zoom body with a zoom range of 0.75X to 5.25X. Only through the internal zoom lens group, the infinite magnification can be changed. During use, a variety of magnification objective lenses can be used according to different working distances. The light emitted by the LED light source 16 is refracted by the lens and the reflector, and then reflected by the beam splitter and converged, and then emitted by the objective lens as parallel light to the cross mark position at the lower observation point, and then reflected back in parallel, and then converged on the CCD camera 15 through the objective lens, the beam splitter, and the tube lens, and observed through the camera software.

[0103] Traditional coaxial alignment and calibration technology often faces the problem of limited adjustment space within the adjustment range. It often relies on technology and experience judgment, which is not only time-consuming and labor-intensive, but also prone to human errors. It is difficult for non-professionals to get started. There is a lack of immediate feedback mechanism, making it difficult to judge whether the optimal alignment state has been reached. It is restrictive, and different equipment may require different types of adjustment devices, which limits its versatility and accuracy.

[0104] This embodiment proposes a coaxial alignment device that uses a microscope system 14 to observe the rotation of the bearing 7. The core of this technology is to use a camera with a small pixel to capture the center of the bearing 7 and adjust the microcomputer for precise adjustment at the same time.

[0105] When using the bearing 7 coaxial alignment device, the bright field 90° crosshair differentiation plate 1 fixed at the center of the four-dimensional precision frame below can be observed through the microscope system 14, and the adjustment screws in the XY axis direction on the four-dimensional precision frame can be directly used to gradually deduce the position of the "fixed point" in continuous manual rotation and keep approaching until the center position of the plane where the cross mark is located coincides with the center of the bearing 7. The entire device is based on the center of the bearing 7 from top to bottom, with good consistency and stability, and the height can be adjusted according to the actual usage scenario during use.

[0106] Such a device layout is not only simple, but also clear whether the upper and lower planes are coincident with the center of the bearing 7. When the whole device is used, it solves the problem of finding the reference for coaxial alignment. The confirmed reference is directly used for debugging. The whole adjustment process is simple and easy to operate. The synchronization during the coaxial debugging process is good, and immediate feedback can be obtained. The rotation center of the bearing 7 and the center position interval of the cross mark can be intuitively observed, which is more convenient for adjustment to the accuracy requirements. This device can shorten the alignment time to one third of the original time, and at the same time can improve the alignment accuracy to the sub-micron level, significantly improving the integrity and reliability of the optical system.

[0107] Because the device uses the bearing 7 for alignment, the entire device always uses the center of the bearing 7 as a reference, avoiding the difficulty in finding the reference in the previous alignment system. The accuracy of the bearing 7 in the device is the alignment accuracy. The micrometer can be used in advance to place the probe on the outer ring or inner ring of the bearing 7, install the bearing 7 on a rotating platform, rotate the bearing 7, and observe the change in the probe reading to reflect the accuracy of the radial jump. This method can be selected according to actual use needs, which is more flexible.

[0108] The device of the present invention can greatly reduce the workload of the adjustment personnel while meeting the high precision of coaxial alignment, reduce the complexity and cost of the overall mechanical structure, reduce the degree of its influence by the outside world, and improve stability. The crossed roller bearing is a very critical device in the present device. The internal structure of the crossed roller bearing adopts rollers arranged perpendicularly and crosswise at 90 degrees (this is also the origin of the name of the crossed roller bearing). Spacers or isolation blocks are installed between the rollers to prevent the rollers from tilting or the rollers from rubbing against each other, effectively preventing the increase of the rotational torque, and having excellent rotational accuracy, which is exactly the working plane scene required by the present device. The rotation of the bearing is caused by the relative movement of the inner and outer rings. The center of rotation is the geometric fixed point when the bearing rotates. At this time, when using a microscope system for observation, the center of the field of view is exactly aligned with the rotation center of the bearing. At this time, other marks or features will become relatively static and fixed in the center of the field of view of the microscope system. The device of the present invention uses this point characteristic to achieve the effect.

[0109] This embodiment also provides a coaxial alignment method, wherein the display plate 1 and the display plate 2 with a center mark use a bright field 90° crosshair differentiation plate 1, the center of the crosshairs is the center mark, the adjustment frame 10 and the adjustment frame 2 12 use a four-dimensional adjustment frame, the microscope system 14 uses a continuous zoom microscope system; the bearing 7 uses a high-precision cross roller bearing. The above method includes the following steps:

[0110] Step 1, connect a bright field 90° cross-line differentiation plate 1 to the center of a differentiation plate seat 2, and the differentiation plate seat 2 is connected to the center hole of the adjustment frame 10; connect another bright field 90° cross-line differentiation plate 1 to the center of another differentiation plate seat 2, and the differentiation plate seat 2 is connected to the center hole of the adjustment frame 2 12;

[0111] Step 2: Build the continuous zoom microscope system above;

[0112] Step 3, build an XYZ three-axis cross-guide type manual displacement platform 5 below the continuous zoom microscope system, connect the outer ring of the bearing 7 to the XYZ three-axis cross-guide type manual displacement platform 5 through the bearing fixing plate 6, the inner ring of the bearing 7 is connected to the connecting plate 8, the connecting plate 8 is connected to the adjusting mirror frame 10 through the connecting plate 9, and the adjusting mirror frame 10 is located above the bearing 7;

[0113] Step 4: Open the camera software in the zoom microscope system, adjust the distance between the zoom microscope system and the bright field 90° crosshair differentiation plate 1 in the adjustment frame 10 to find the best imaging position of the bright field 90° crosshair differentiation plate 1 in the camera software, adjust the x and y axis directions on the adjustment frame 10, and then move the center of the cross mark of the bright field 90° crosshair differentiation plate 1 to the center of the target surface of the camera;

[0114] Step 5, rotate the inner ring of the bearing 7, and observe the movement trajectory of the cross mark of the bright field 90° cross-line differentiation plate 1 in the adjustment frame 10 through the camera software. The center of the cross mark rotates in a regular circle, and the center of the circle is recorded as the fixed point; rotate the inner ring of the bearing 7 and adjust the x and y axis directions on the adjustment frame 10 so that the center of the cross mark of the bright field 90° cross-line differentiation plate 1 therein approaches the position of the fixed point; use the magnification function of the continuous zoom microscope system to adjust the distance between the continuous zoom microscope system and the bright field 90° cross-line differentiation plate 1 in the adjustment frame 10 again to find the best imaging position of the bright field 90° cross-line differentiation plate 1 in the camera software. At this time, the image in the camera target surface becomes larger, and repeatedly rotate the inner ring of the bearing 7 and adjust the x and y axis directions on the adjustment frame 10 so that the center of the cross mark of the bright field 90° cross-line differentiation plate 1 therein approaches the position of the fixed point;

[0115] Step 6, continue to rotate the inner ring of the bearing 7, and adjust the x and y axis directions on the mirror frame 10 at the same time, so that the center of the cross mark of the bright field 90° cross line differentiation plate 1 is close to the position of the fixed point;

[0116] Step 7, using the inner ring of the bearing 7 to rotate the bright field 90° cross-line differentiation plate 1 in the adjustment frame 10 by 360°, and evenly intercepting ten images of the bright field 90° cross-line differentiation plate 1 within 360°;

[0117] Step 8, extract features from the ten images captured by the camera software, calculate the coordinate position of the center of the cross mark of the bright field 90° cross line differentiation plate 1 in the image, obtain the motion trajectory of the center of the cross mark of the bright field 90° cross line differentiation plate 1, and calculate the radius of the motion trajectory of the center point moving around the fixed point;

[0118] Step 9, repeating steps 6-8 until the radius of the central motion trajectory of the cross mark of the bright field 90° cross line differentiation plate 1 in the image is less than a preset value, and then executing step 10;

[0119] Step 10, connect the second connecting plate 11 with the first connecting plate 9, connect the second connecting plate 11 with the second adjusting frame 12, the second adjusting frame 12 is located above the first adjusting frame 10, and ensure that the second adjusting frame 12 is arranged parallel to the first adjusting frame 10;

[0120] Step 11, adjusting the distance between the continuous zoom microscope system and the bright field 90° crosshair differentiation plate 1 in the second adjustment frame 12 to find the best imaging position of the bright field 90° crosshair differentiation plate 1 in the camera software, adjusting the x and y axis directions on the second adjustment frame 12, and then moving the center of the cross mark of the bright field 90° crosshair differentiation plate 1 to the center of the target surface of the camera;

[0121] Step 12, rotate the inner ring of the bearing 7, observe the movement trajectory of the cross mark of the bright field 90° cross-line differentiation plate 1 in the second frame 12 through the camera software, the center of the cross mark rotates in a regular circle, and the center of the circle is recorded as the fixed point; rotate the inner ring of the bearing 7 and adjust the x and y axis directions on the second frame 12, so that the center of the cross mark of the bright field 90° cross-line differentiation plate 1 therein is close to the position of the fixed point; use the magnification function of the continuous zoom microscope system, adjust the distance between the continuous zoom microscope system and the bright field 90° cross-line differentiation plate 1 in the second frame 12 again to find the best imaging position of the bright field 90° cross-line differentiation plate 1 in the camera software, at this time, the image in the camera target surface becomes larger, repeatedly rotate the inner ring of the bearing 7 and adjust the x and y axis directions on the second frame 12, so that the center of the cross mark of the bright field 90° cross-line differentiation plate 1 therein is close to the position of the fixed point;

[0122] Step 13, continue to rotate the inner ring of the bearing 7, and at the same time adjust the x and y axis directions on the second mirror frame 12, so that the center of the cross mark of the bright field 90° cross line differentiation plate 1 is close to the position of the fixed point;

[0123] Step 14, using the inner ring of the bearing 7 to rotate the bright field 90° cross-line differentiation plate 1 in the adjustment frame 12 by 360°, and evenly intercepting ten images of the bright field 90° cross-line differentiation plate 1 within 360°;

[0124] Step 15, extract features from the ten images captured by the camera software, calculate the coordinate position of the center of the cross mark of the bright field 90° cross line differentiation plate 1 in the image, obtain the motion trajectory of the center of the cross mark of the bright field 90° cross line differentiation plate 1, and calculate the radius of the motion trajectory of the center point moving around the fixed point;

[0125] Step 16, repeat steps 13-15 until the radius of the central motion trajectory of the cross mark of the bright field 90° cross line differentiation plate 1 in the image is less than the preset value, and the coaxial alignment of the two bright field 90° cross line differentiation plates 1 is completed. After the alignment is completed, the structure under the bearing 7 is removed, and the remaining structures are connected to the inner ring of the bearing 7, so the structure is more stable, and the mechanical structure will not produce a small displacement when the equipment is operated for a long time.

[0126] The protection scope of the present invention includes but is not limited to the above embodiments. The protection scope of the present invention shall be based on the claims. Any replacement, deformation, and improvement of the technology that can be easily thought of by technicians in this field shall fall within the protection scope of the present invention.

Claims

1. A coaxial alignment device, characterized in that: It includes bearings, an adjustment mirror frame, a display plate to be coaxially aligned, a microscope system and a platform; The outer ring of the bearing is connected to the platform, the inner ring of the bearing is connected to the adjustment mirror frame, and the adjustment mirror frame is located above the bearing; A center mark is provided at the center of the display plate, and the display plate is connected to the center of the adjustment frame; The microscope system is mounted above the adjusting mirror frame and is used to observe the movement track of the center mark of the display plate in the adjusting mirror frame.

2. The coaxial alignment device according to claim 1, characterized in that: There are multiple adjusting mirror frames and display boards to be coaxially aligned, the center of each adjusting mirror frame is connected to a display board, and the multiple adjusting mirror frames are connected in sequence from bottom to top.

3. The coaxial alignment device according to claim 2, characterized in that: There are two adjusting mirror frames, respectively denoted as adjusting mirror frame one and adjusting mirror frame two; there are two display boards, respectively denoted as display board one and display board two; display board one is fixedly connected at the center of board seat one, and board seat one is threadedly connected in the center hole of adjusting mirror frame one; display board two is fixedly connected at the center of board seat two, and board seat two is threadedly connected in the center hole of adjusting mirror frame two; the inner ring of the bearing is connected to the connecting disk, the connecting disk is connected to the adjusting mirror frame one through the connecting plate one, and the adjusting mirror frame two is connected to the connecting plate one through the connecting plate two, the adjusting mirror frame one is located above the bearing, and the adjusting mirror frame two is located above the adjusting mirror frame one.

4. The coaxial alignment device according to claim 3, characterized in that: The display plate 1 and the display plate 2 are both bright field 90° cross line differentiation plates, and the plate holder 1 and the plate holder 2 are both differentiation plate holders; There is a through hole in the center of the differentiation plate seat, and a circular groove at the bottom for placing the bright field 90° cross-line differentiation plate. The center of the circular groove is the center of the through hole, and the bright field 90° cross-line differentiation plate is fixedly connected in the circular groove by silicone.

5. The coaxial alignment device according to claim 1, characterized in that: The second connecting plate is connected to the Z-axis guide rail platform, and the second adjusting mirror frame is connected to a slider in the Z-axis guide rail platform.

6. The coaxial alignment device according to claim 1, characterized in that: The platform adopts an XYZ three-axis cross-guide manual displacement platform, the bottom of the platform is connected to the air-floating platform through a base plate, the adjustment mirror frame adopts a four-dimensional adjustment mirror frame, the microscope system adopts a continuous zoom microscope system, and the bearing adopts a cross roller bearing.

7. The coaxial alignment device according to claim 3, characterized in that: The outer ring of the bearing is connected to the platform through a bearing fixing plate and bolts, the inner ring of the bearing is threadedly connected to the connecting plate, the bottom of the connecting plate one is connected to the connecting plate through bolts, the top of the connecting plate one is connected to the adjusting mirror frame one through bolts, the bottom of the connecting plate two is connected to the Z-axis guide platform through bolts, and the adjusting mirror frame two is connected to a slider in the Z-axis guide platform through bolts.

8. A coaxial alignment method, characterized in that: The following steps are involved: Step 1, fix the display plate 1 with the center mark in the center hole of the adjustment frame 1, and fix the display plate 2 with the center mark in the center hole of the adjustment frame 2; Step 2: Build the upper microscope system; Step 3, build a platform below the microscope system, connect the outer ring of the bearing to the platform, connect the inner ring of the bearing to the adjustment frame 1, and the adjustment frame 1 is located above the bearing; Step 4, open the camera software in the microscope system, adjust the distance between the microscope system and the display board 1 to find the best imaging position of the display board 1 in the camera software, adjust the x and y axis directions on the frame 1, and then move the center mark of the display board 1 to the center of the target surface of the camera; Step 5: Rotate the inner ring of the bearing and observe the motion trajectory of the center mark of the display board 1 through the camera software. The center mark of the display board 1 rotates in a regular circle, and the center of the circle is recorded as the fixed point; Step 6: Continue to rotate the inner ring of the bearing, and adjust the x-axis and y-axis directions on the mirror frame 1 at the same time, so that the center mark of the display board 1 is close to the fixed point; Step 7, using the inner ring of the bearing to rotate the display board 1 360°, and evenly intercepting ten images of the display board 1 within 360°; Step 8: extract features from the ten images captured by the camera software, calculate the coordinate position of the center mark of the display board 1, obtain the motion trajectory of the center mark of the display board 1, and calculate the radius of the motion trajectory of the center mark moving around the fixed point; Step 9, repeat steps 6-8 until the radius of the center mark motion trajectory of the display plate 1 is less than a preset value, and then execute step 10; Step 10, connecting the second connecting plate to the first connecting plate, connecting the second connecting plate to the second adjusting frame, the second adjusting frame being located above the first adjusting frame, and ensuring that the second adjusting frame is arranged parallel to the first adjusting frame; Step 11, adjust the distance between the microscope system and the second display board to find the best imaging position of the second display board in the camera software, adjust the x and y axis directions on the second mirror frame, and move the center mark of the second display board to the center of the target surface of the camera; Step 12, rotate the inner ring of the bearing, and observe the motion trajectory of the center mark of the second display board through the camera software. The center mark of the second display board rotates in a regular circle, and the center of the circle is recorded as the fixed point; Step 13, continue to rotate the inner ring of the bearing, and adjust the x and y axis directions on the second mirror frame at the same time, so that the center mark of the second display board is close to the fixed point; Step 14, using the inner ring of the bearing to rotate the display board 2 360°, and evenly intercepting ten images of the display board 2 within 360°; Step 15, extract features from the ten images captured by the camera software, calculate the coordinate position of the center mark of the second display board, obtain the motion trajectory of the center mark of the second display board, and calculate the radius of the motion trajectory of the center mark moving around the fixed point; Step 16: Repeat steps 13-15 until the radius of the motion trajectory of the center mark of the second display board is smaller than a preset value, thereby completing the coaxial alignment of the first display board and the second display board.

9. The coaxial alignment method according to claim 8, characterized in that: The display plate 1 and the display plate 2 are both bright field 90° cross-line differentiation plates, the adjustment mirror frame 1 and the adjustment mirror frame 2 are both four-dimensional adjustment mirror frames, and the microscope system adopts a continuous zoom microscope system; The step 1 is specifically as follows: Connect a bright field 90° cross-line differentiation plate to the center of a differentiation plate holder, and the differentiation plate holder is connected to the center hole of the adjustment mirror frame; Connect another bright field 90° cross-line differentiation plate to the center of another differentiation plate holder, and the differentiation plate holder is connected to the center hole of the second adjustment mirror frame; The step 3 is specifically as follows: An XYZ three-axis cross-guide manual displacement platform is built below the continuous zoom microscope system, the outer ring of the bearing is connected to the XYZ three-axis cross-guide manual displacement platform through a bearing fixing plate, the inner ring of the bearing is connected to a connecting plate, the connecting plate is connected to an adjusting mirror frame one through a connecting plate one, and the adjusting mirror frame one is located above the bearing; The step 4 is specifically as follows: Open the camera software in the zoom microscope system, adjust the distance between the zoom microscope system and the bright field 90° crosshair differentiation plate in the adjustment frame 1 to find the best imaging position of the bright field 90° crosshair differentiation plate in the camera software, adjust the x and y axis directions on the adjustment frame 1, and then move the center of the cross mark of the bright field 90° crosshair differentiation plate therein to the center of the target surface of the camera; The step 5 is specifically as follows: Rotate the inner ring of the bearing and observe the motion trajectory of the cross mark on the 90° cross-line differentiation plate of the bright field in the frame through the camera software. The center of the cross mark rotates in a regular circle, and the center of the circle is recorded as the fixed point; Rotate the inner ring of the bearing and adjust the x and y axis directions on the first mirror frame so that the center of the cross mark on the bright field 90° crosshair differentiation plate is close to the fixed point; Use the zoom function of the zoom microscope system to adjust the distance between the zoom microscope system and the bright field 90° crosshair differentiation plate in the adjustment frame 1 again to find the best imaging position of the bright field 90° crosshair differentiation plate in the camera software. At this time, the image on the camera target surface becomes larger. Repeatedly rotate the inner ring of the bearing and adjust the x and y axis directions on the adjustment frame 1 so that the center of the cross mark of the bright field 90° crosshair differentiation plate is close to the fixed point. The step 6 is specifically as follows: Continue to rotate the inner ring of the bearing, and adjust the x and y axis directions on the mirror frame 1 at the same time, so that the center of the cross mark on the bright field 90° crosshair differentiation plate is close to the fixed point; The step 7 is specifically as follows: The bright field 90° cross-line differentiation plate in the adjustment frame 1 is rotated 360° by using the inner ring of the bearing, and ten images of the bright field 90° cross-line differentiation plate are evenly intercepted within 360°; The step 8 is specifically as follows: Perform feature extraction on the ten images captured by the camera software, calculate the coordinate position of the center of the cross mark of the bright field 90° cross-line differentiation plate in the image, obtain the motion trajectory deduction of the center of the cross mark of the bright field 90° cross-line differentiation plate, and calculate the radius of the motion trajectory of the center point moving around the fixed point; The step 9 is specifically as follows: Repeat steps 6-8 until the radius of the central motion trajectory of the cross mark of the bright field 90° cross line differentiation plate in the image is less than a preset value, and then execute step 10; The step 11 is specifically as follows: Adjust the distance between the zoom microscope system and the bright field 90° crosshair differentiation plate in the second adjustment mirror frame to find the best imaging position of the bright field 90° crosshair differentiation plate in the camera software, adjust the x and y axis directions on the second adjustment mirror frame, and then move the center of the cross mark of the bright field 90° crosshair differentiation plate to the center of the target surface of the camera; The step 12 is specifically as follows: Rotate the inner ring of the bearing and observe the movement trajectory of the cross mark on the 90° cross-line differentiation plate of the bright field in the second frame through the camera software. The center of the cross mark rotates in a regular circle, and the center of the circle is recorded as the fixed point; Rotate the inner ring of the bearing and adjust the x and y axis directions on the second mirror frame so that the center of the cross mark on the bright field 90° crosshair differentiation plate is close to the fixed point; Use the zoom function of the zoom microscope system to adjust the distance between the zoom microscope system and the bright field 90° crosshair differentiation plate in the second adjustment mirror frame again to find the best imaging position of the bright field 90° crosshair differentiation plate in the camera software. At this time, the image on the camera target surface becomes larger. Repeatedly rotate the inner ring of the bearing and adjust the x and y axis directions on the second adjustment mirror frame so that the center of the cross mark of the bright field 90° crosshair differentiation plate is close to the fixed point. The step 13 is specifically as follows: Continue to rotate the inner ring of the bearing, and adjust the x and y axis directions on the second mirror frame at the same time, so that the center of the cross mark on the bright field 90° crosshair differentiation plate is close to the fixed point; The step 14 is specifically as follows: The bright field 90° cross-line differentiation plate in the second adjustment mirror frame is rotated 360° by using the inner ring of the bearing, and ten images of the bright field 90° cross-line differentiation plate are evenly intercepted within 360°; The step 15 is specifically as follows: Perform feature extraction on the ten images captured by the camera software, calculate the coordinate position of the center of the cross mark of the bright field 90° cross-line differentiation plate in the image, obtain the motion trajectory deduction of the center of the cross mark of the bright field 90° cross-line differentiation plate, and calculate the radius of the motion trajectory of the center point moving around the fixed point; The step 16 is specifically as follows: Repeat steps 13-15 until the radius of the central motion trajectory of the cross mark of the bright field 90° cross-line differentiation plate in the image is smaller than a preset value, thereby completing the coaxial alignment of the two bright field 90° cross-line differentiation plates.

Images