Lens reference axis positioning platform and lens reference axis positioning method

Abstract

The invention provides a lens reference axis positioning platform and a lens reference axis positioning method.The lens reference axis positioning platform comprises a transverse adjusting table, the transverse adjusting table comprises a plurality of adjustably-arranged bearing tables, the bearing tables are used for fixing a to-be-detected lens, and the transverse adjusting table can move in an xy plane and adjust the pitching angle relative to the xy plane; the lifting tables are arranged above the transverse adjusting table at intervals, the lifting tables can be close to or away from the transverse adjusting table in the extending direction of the z-axis, and the z-axis is perpendicular to the xy plane; the telecentric camera is fixed on the lifting platform, and the telecentric camera is used for detecting the appearance reference position of the to-be-detected lens; and the positioning ball is fixed on the transverse adjusting table, so that the telecentric camera can position the transverse adjusting table. The problems that in the prior art, the lens reference axis positioning precision is low, and the jig universality is poor are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of lens eccentricity detection, and more particularly, to a lens reference axis positioning platform and a lens reference axis positioning method. Background Art

[0002] In the production, detection, and assembly processes of optical lenses, the positioning of the lens reference axis is a key step to ensure the optical performance and mechanical assembly accuracy of the lens. The eccentricity detection and assembly of the lens need to be carried out with reference to the lens reference axis. Generally, the lens reference axis is defined by the mechanical center and the contour reference set during the lens design and processing stages. However, in the existing lens eccentricity detection systems and assembly processes, there are many limitations in the positioning method of the lens reference axis.

[0003] Currently, in a lens eccentricity detection system, a customized high-precision jig is usually used to position the lens reference axis. When designing this jig, it is necessary to accurately match the mechanical center and the contour reference of the lens, and at the same time, high-precision feature points are added to the jig for positioning the eccentricity detection probe. Although this method can provide high positioning accuracy, a dedicated jig needs to be designed and manufactured for each lens, resulting in high costs, long processing cycles, and poor versatility of the jig. Especially when facing lenses of different sizes and shapes, the replacement and adjustment of the jig become complicated, reducing the production efficiency.

[0004] In addition, the traditional positioning method has extremely high requirements for the accuracy of the jig. Any minor manufacturing error or the fitting deviation between the lens and the jig will directly affect the accuracy of the reference axis positioning. In a large-scale production environment, the recalibration and maintenance of the jig are also time-consuming and costly processes, further limiting the flexibility and efficiency of the positioning system.

[0005] That is to say, in the prior art, there are problems of low accuracy and poor jig versatility in the positioning of the lens reference axis. Summary of the Invention

[0006] The main object of the present invention is to provide a lens reference axis positioning platform and a lens reference axis positioning method to solve the problems of low accuracy and poor jig versatility in the positioning of the lens reference axis in the prior art.

[0007] To achieve the above object, according to one aspect of the present invention, there is provided a lens reference axis positioning platform, comprising: a lateral adjustment table, the lateral adjustment table includes a plurality of adjustably arranged supporting tables for fixing the lens to be measured, and the lateral adjustment table can move in the xy plane and adjust the pitching angle relative to the xy plane; a lifting table, the lifting table is arranged above the lateral adjustment table at intervals, and the lifting table can approach or move away from the lateral adjustment table along the extension direction of the z-axis, and the z-axis is perpendicular to the xy plane; a telecentric camera, the telecentric camera is fixed on the lifting table and is used for detecting the contour reference position of the lens to be measured; a positioning ball, the positioning ball is fixed on the lateral adjustment table so that the telecentric camera can locate the lateral adjustment table.

[0008] Further, the lateral adjustment table includes: a displacement adjustment table that can translate in the xy plane; a pitching adjustment table fixed on the displacement adjustment table, the pitching adjustment table can adjust the pitching angle relative to the xy plane, and the lens to be measured is fixed on the pitching adjustment table.

[0009] Further, the pitching adjustment table has a lens jig plane, and the supporting table and the positioning ball are arranged on the lens jig plane.

[0010] Further, the lens reference axis positioning platform further includes a point light source arranged towards the lateral adjustment table, the point light source and the telecentric camera form a coaxial optical path, and the lens jig plane and the top surface of the supporting table can reflect the light emitted by the point light source.

[0011] Further, the positioning ball is located at the center of the lens jig plane.

[0012] Further, the lateral adjustment table includes four supporting tables, and the four supporting tables surround the positioning ball and are arranged opposite to each other in pairs.

[0013] Further, the single-direction positioning accuracy of the displacement adjustment table is less than or equal to 0.5 μm; and / or the repeat positioning accuracy of the displacement adjustment table is less than or equal to 0.1 μm.

[0014] Further, the step of the lifting table is less than or equal to 2 μm; and / or the repeat positioning accuracy of the lifting table is less than or equal to 1 μm.

[0015] Further, the object-side resolution of the telecentric camera is less than or equal to 1 μm; and / or the depth of field of the telecentric camera is less than or equal to 10 μm; and / or the detection error of the telecentric camera is less than or equal to 1 μm.

[0016] Further, the spatial angle between the side surface and the top surface of the supporting table is within the range of 90 ± 0.5°; and / or the straightness error of the side edge of the supporting table is less than or equal to 10 μm.

[0017] According to another aspect of the present invention, there is provided a method for positioning the reference axis of a lens. The spatial position of the reference axis of the lens to be measured is positioned by using the above-mentioned lens reference axis positioning platform. The method for positioning the reference axis of the lens includes: obtaining the lens to be measured; calibrating the mapping relationship between the image coordinate system of the telecentric camera of the lens reference axis positioning platform and the physical space coordinate system of the lateral adjustment table of the lens reference axis positioning platform according to the shape of the lens to be measured; determining the fitting position of the outer shape reference line of the lens to be measured in the physical space coordinate system according to the mapping relationship; obtaining the preset relationship between the reference axis and the outer shape reference line of the lens to be measured; and solving the spatial position of the reference axis in the physical space coordinate system according to the fitting position and the preset relationship.

[0018] Further, in the process of calibrating the mapping relationship between the image coordinate system of the telecentric camera of the lens reference axis positioning platform and the physical space coordinate system of the lateral adjustment table of the lens reference axis positioning platform according to the shape of the lens to be measured, it includes: imaging the positioning ball by the telecentric camera to obtain the position of the positioning ball in the physical space coordinate system at (x stage , y stage ) and the position of the center of the ball of the positioning ball on the image coordinate system (x img , y img ); adjusting the position of the positioning ball of the lens reference axis positioning platform to obtain the corresponding center coordinates of the ball at different positions; and calculating the mapping relationship of the image coordinate system Img(x img , y img ) relative to the physical space coordinate system Stage(x stage , y stage ).

[0019] Further, in the process of adjusting the position of the positioning ball of the lens reference axis positioning platform to obtain the corresponding center coordinates of the ball at different positions, it includes: adjusting the displacement adjustment table and the lifting table of the lateral adjustment table to make the positioning ball image at the center of the field of view of the telecentric camera; recording the coordinates of the displacement adjustment table in the physical space coordinate system (x stage0 , y stage0 ) and the coordinates of the center of the ball of the positioning ball on the image coordinate system (x img0 , y img0 ); adjusting the displacement adjustment table to move to the coordinates of the physical space coordinate system (x stage1 , y stage0 ), (x stage2 , y stage0 ), (x stage0 , y stage1 ), (x stage0 , y stage2 ) respectively, and recording the coordinates of the center of the ball of the positioning ball on the image coordinate system (x img1 , y img1 ), (x img2 , yimg2 ), (x img3 , y img3 ), (x img4 , y img4 ), where x stage1 = x stage0 + 5μm, x stage2 = x stage0 + 10μm, y stage1 = y stage0 + 5μm, y stage2 = x stage0 + 10μm.

[0020] Further, in the process of calculating the mapping relationship between the image coordinate system Img(x img , y img ) and the physical space coordinate system Stage(x stage , y stage ), it includes: Img(x img , y img ) and Stage(x stage , y stage ) satisfy formulas (10) and (20):

[0021]

[0022] Wherein, the calibration coefficient β is the linear magnification coefficient between the image coordinate system and the physical space coordinate system, the calibration coefficient R is the relative rotation matrix between the image coordinate system and the physical space coordinate system, and the calibration coefficient T is the relative offset matrix between the image coordinate system and the physical space coordinate system.

[0023] Further, before the process of calibrating the mapping relationship between the image coordinate system of the telecentric camera on the lens reference axis positioning platform and the physical space coordinate system of the lateral adjustment table of the lens reference axis positioning platform according to the shape of the lens to be measured, it also includes: calibrating that the bearing table of the lateral adjustment table and the imaging plane of the telecentric camera are horizontal relative to each other.

[0024] Further, the number of bearing tables is four, and the four bearing tables are the first bearing table to the fourth bearing table respectively. In the process of calibrating that the bearing table of the lateral adjustment table and the imaging plane of the telecentric camera are horizontal relative to each other, it includes: according to the shape of the lens to be measured, adjusting the positions of the four bearing tables so that all bearing tables are in contact with the bearing surface of the lens to be measured; adjusting the displacement adjustment table of the lateral adjustment table so that the first bearing table is imaged at the center of the field of view of the telecentric camera; adjusting the height of the lifting table of the lens reference axis positioning platform, and recording the height Z of the lifting table when the edge contour image of the first bearing table is the clearest 1 ; respectively recording the height Z of the lifting table when the edge contour images corresponding to the second bearing table to the fourth bearing table are the clearest when they are imaged at the center of the field of view of the telecentric camera 2to Z 4 ; Calculate the height difference Z 1 -Z 2 and the height difference Z 3 -Z 4 ; Adjust the pitching stage of the lateral adjustment stage, repeat the measurement and calculate the height difference Z 1- Z 2 and the height difference Z 3 -Z 4 , until |Z 1 -Z 2 | ≤ 10μm, |Z 3 -Z 4 | ≤ 10μm.

[0025] Furthermore, in the process of determining the fitting position of the contour reference line of the lens to be measured in the physical space coordinate system according to the mapping relationship, it includes: fitting and fixing the bearing surface of the lens to be measured with the side surface of the bearing stage; obtaining the first contour reference and the second contour reference of the lens to be measured; calculating the first contour equation Fa on the physical space coordinate system corresponding to the first contour reference and the second contour equation Fb on the physical space coordinate system corresponding to the second contour reference according to the mapping relationship.

[0026] Furthermore, in the process of calculating the first contour equation Fa on the physical space coordinate system corresponding to the first contour reference and the second contour equation Fb on the physical space coordinate system corresponding to the second contour reference according to the mapping relationship, it includes: adjusting the displacement adjustment stage and the lifting stage to make the first contour reference clearly imaged in the telecentric camera, and recording the coordinates (x stage_a , y stage_a ) of the displacement adjustment stage; calculating the coordinate set (x img_a1 , y img_a1 ) ~ (x img_an , y img_an ) of N points on the edge of the first contour reference in the image coordinate system; converting the coordinate set (x img_a1 , y img_a1 ) ~ (x img_an , y img_an ) to the coordinate set (x stage_a1 , y stage_a1 ) ~ (x stage_an , y stage_an ) of the physical space coordinate system by using formula (30) according to the calibration coefficient β, the calibration coefficient R and the calibration coefficient T,

[0027]

[0028] According to the coordinate set (x stage_a1 , y stage_a1 ) ~ (x stage_an , y stage_an),Fit and calculate the first outer shape equation Fa.

[0029] Further, in the process of calculating the first outer shape equation Fa in the physical space coordinate system corresponding to the first outer shape reference and the second outer shape equation Fb in the physical space coordinate system corresponding to the second outer shape reference according to the mapping relationship, it further includes: adjusting the displacement adjustment table and the lifting table to make the second outer shape reference clearly imaged in the telecentric camera, and recording the coordinates of the displacement adjustment table (x stage_b , y stage_b ); calculating the coordinate set (x img_b1 , y img_b1 )~(x img_bn , y img_bn ) of N points on the edge of the second outer shape reference in the image coordinate system; according to the calibration coefficient β, the calibration coefficient R, and the calibration coefficient T, using formula (40) to convert the coordinate set (x img_b1 , y img_b1 )~(x img_bn , y img_bn ) into the coordinate set (x stage_b1 , y stage_b1 )~(x stage_bn , y stage_bn ) in the physical space coordinate system,

[0030]

[0031] According to the coordinate set (x stage_b1 , y stage_b1 )~(x stage_bn , y stage_bn ), fit and calculate the second outer shape equation Fb.

[0032] Further, in the process of obtaining the preset relationship between the reference axis and the outer shape reference line of the lens to be measured, it includes: obtaining the processing drawing of the lens to be measured; determining the distance La between the reference axis of the lens to be measured and the first outer shape reference; determining the distance Lb between the reference axis of the lens to be measured and the second outer shape reference.

[0033] Further, in the process of solving the spatial position of the reference axis in the physical space coordinate system according to the fitting position and the preset relationship, it includes: solving the point coordinates (x stage_cen , y stage_cen ) such that the distance to the first outer shape equation Fa is La and the distance to the second outer shape equation Fb is Lb at the same time, and the point coordinates (x stage_cen , y stage_cen ) are the position of the reference axis in the physical space coordinate system.

[0034] Applying the technical solution of the present invention, the lens reference axis positioning platform includes a horizontal adjustment table, a lifting table, a telecentric camera, and a positioning ball. The horizontal adjustment table includes a plurality of adjustable supporting platforms for fixing the lens to be measured. The horizontal adjustment table can move within the xy plane and adjust the pitching angle relative to the xy plane; the lifting table is arranged above the horizontal adjustment table at intervals, and the lifting table can approach or move away from the horizontal adjustment table along the extension direction of the z-axis, and the z-axis is perpendicular to the xy plane; the telecentric camera is fixed on the lifting table, and the telecentric camera is used to detect the external reference position of the lens to be measured; the positioning ball is fixed on the horizontal adjustment table so that the telecentric camera can position the horizontal adjustment table.

[0035] The horizontal adjustment table includes a plurality of adjustable supporting platforms for fixing lenses to be measured with different sizes and shapes, ensuring the stability and accuracy of the lenses during the detection process. The horizontal adjustment table can move within the xy plane and adjust the pitching angle to meet the detection requirements of different lenses, calibrate the relative level between the horizontal adjustment table and the telecentric camera plane, so as to ensure that the reference axis of the lens to be measured is perpendicular to the telecentric camera plane. Ensure the relative position between the lens and the telecentric camera is accurate. The lifting table is arranged above the horizontal adjustment table at intervals and can approach or move away from the horizontal adjustment table along the extension direction of the z-axis, and the z-axis is perpendicular to the xy plane. By precisely controlling the movement of the lifting table, the distance between the telecentric camera and the lens to be measured can be adjusted to ensure the clarity and accuracy of the imaging. The positioning ball is fixed on the horizontal adjustment table so that the telecentric camera can position the horizontal adjustment table. Through the precise imaging of the positioning ball, the relative position between the telecentric camera and the horizontal adjustment table can be calibrated, and then the mapping relationship between the image coordinate system of the telecentric camera and the physical space coordinate system of the horizontal adjustment table can be calibrated. Further, in the actual lens detection, it can be used to position the reference of the lens to be measured within the range of the space coordinate system of the current horizontal adjustment table. In addition, the lens reference axis positioning platform of the present application has low requirements for the accuracy of the lens fixture and can adapt to different lenses, so it has high versatility. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The accompanying drawings forming a part of this application are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0037] Figure 1 shows a schematic structural diagram of a lens reference axis positioning platform according to an optional embodiment of the present invention;

[0038] Figure 2 shows a schematic diagram of the calibration point position marks of the image coordinate system and the physical space coordinate system according to an optional embodiment of the present invention;

[0039] Figure 3Shows a schematic diagram of the position marks of the first contour reference, the second contour reference and the reference axis of an alternative embodiment of the present invention in different coordinate systems;

[0040] Figure 4 Shows a flowchart of the lens reference axis positioning method of any alternative embodiment of the present invention.

[0041] Among them, the above-mentioned drawings include the following reference numerals:

[0042] 1. Lifting table; 2. Telecentric camera; 3. Point light source; 4. Supporting table; 5. Lens jig plane; 6. Positioning ball; 7. Pitch adjustment table; 8. Displacement adjustment table. Detailed implementation manners

[0043] It should be noted that, without conflict, the embodiments in the present application and the features in the embodiments may be combined with each other. The present invention will be described in detail below with reference to the drawings and in combination with the embodiments.

[0044] It should be pointed out that unless otherwise specified, all technical and scientific terms used in the present application have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present application belongs.

[0045] In the present invention, unless otherwise stated, the orientation terms such as "upper, lower, top, bottom" are usually in the direction shown in the drawings, or in the vertical, perpendicular or gravitational direction of the component itself; similarly, for the convenience of understanding and description, "inner, outer" refer to the inner and outer of the contour of each component itself, but the above orientation terms are not used to limit the present invention.

[0046] In order to solve the problems of low positioning accuracy of the lens reference axis and poor versatility of the jig in the prior art, the present invention provides a lens reference axis positioning platform and a lens reference axis positioning method.

[0047] As Figures 1 to 4 shown, the lens reference axis positioning platform includes a horizontal adjustment table, a lifting table 1, a telecentric camera 2 and a positioning ball 6. The horizontal adjustment table includes a plurality of adjustable supporting tables 4 for fixing the lens to be measured. The horizontal adjustment table can move in the xy plane and adjust the pitch angle relative to the xy plane; the lifting table 1 is arranged above the horizontal adjustment table at intervals, and the lifting table 1 can approach or move away from the horizontal adjustment table along the extension direction of the z axis, and the z axis is perpendicular to the xy plane; the telecentric camera 2 is fixed on the lifting table 1, and the telecentric camera 2 is used to detect the contour reference position of the lens to be measured; the positioning ball 6 is fixed on the horizontal adjustment table so that the telecentric camera 2 can position the horizontal adjustment table.

[0048] The horizontal adjustment stage includes multiple support stages 4 with adjustable settings, which are used to fix lenses to be measured with different sizes and shapes, ensuring the stability and accuracy of the lenses during the detection process. The horizontal adjustment stage can move within the xy plane and adjust the pitch angle to meet the detection requirements of different lenses, calibrating the relative level between the horizontal adjustment stage and the plane of the telecentric camera 2, so as to ensure that the reference axis of the lens to be measured is perpendicular to the plane of the telecentric camera 2. Ensure the relative position between the lens and the telecentric camera 2 is accurate. The lifting stage 1 is arranged above the horizontal adjustment stage at intervals and can approach or move away from the horizontal adjustment stage along the extension direction of the z-axis. The z-axis is perpendicular to the xy plane. By precisely controlling the movement of the lifting stage 1, the distance between the telecentric camera 2 and the lens to be measured can be adjusted to ensure the clarity and accuracy of imaging. The positioning ball 6 is fixed on the horizontal adjustment stage so that the telecentric camera 2 can locate the horizontal adjustment stage. Through the precise imaging of the positioning ball 6, the relative position between the telecentric camera 2 and the horizontal adjustment stage can be calibrated, and then the mapping relationship between the image coordinate system of the telecentric camera 2 and the physical space coordinate system of the horizontal adjustment stage can be determined. Further, in the actual lens detection, it can be used to locate the reference of the lens to be measured within the range of the space coordinate system of the current horizontal adjustment stage. In addition, the lens reference axis positioning platform of the present application has low requirements for the accuracy of the lens fixture and can adapt to different lenses, so it has high versatility.

[0049] As Figure 1 shown, the horizontal adjustment stage includes a displacement adjustment stage 8 and a pitch adjustment stage 7. The displacement adjustment stage 8 can translate within the xy plane; the pitch adjustment stage 7 is fixed on the displacement adjustment stage 8, and the pitch adjustment stage 7 can adjust the pitch angle relative to the xy plane. The lens to be measured is fixed on the pitch adjustment stage 7. By using the displacement adjustment stage 8 that can translate within the xy plane, precise movement of the lens to be measured in the horizontal direction is provided. At the same time, the pitch adjustment stage 7 is fixed on the displacement adjustment stage 8 and can adjust the pitch angle relative to the xy plane. The lens to be measured is fixed on it. Through the adjustment of the pitch adjustment stage 7, it can be ensured that the imaging plane of the lens to be measured and the telecentric camera 2 remains relatively horizontal, further improving the detection accuracy.

[0050] As Figure 1 shown, the lens reference axis positioning platform further includes a point light source 3 arranged towards the horizontal adjustment stage. The point light source 3 and the telecentric camera 2 form a coaxial optical path. The plane of the lens fixture and the top surface of the support stage 4 can reflect the light emitted by the point light source 3. The point light source 3 provides uniform illumination for the detection process, ensuring clear imaging of the edge contour of the lens to be measured, thereby improving the detection accuracy.

[0051] As Figure 1As shown in the figure, the pitch adjustment table 7 has a lens fixture plane 5, and the bearing platform 4 and the positioning ball 6 are arranged on the lens fixture plane 5. The design of the lens fixture plane 5 ensures the stable fixation of the bearing platform 4 and the positioning ball 6, and at the same time provides a smooth reflecting surface. The lens fixture plane 5 and the top surface of the bearing platform 4 can reflect the light emitted by the point light source 3 for auxiliary positioning. The precise setting of the bearing platform 4 and the positioning ball 6 enables the telecentric camera 2 to accurately detect the shape reference of the lens to be measured and position the reference axis of the lens to be measured, improving the accuracy and efficiency of detection.

[0052] As Figure 1 shown, the positioning ball 6 is located at the center of the lens fixture plane 5 and serves as a positioning reference point for calibrating the relative position between the telecentric camera 2 and the pitch adjustment table 7 to ensure the positioning accuracy during the detection process.

[0053] Preferably, the positioning ball 6 is a high-precision smooth ceramic ball with a high sphericity to ensure the calibration accuracy between the lens fixture plane 5 and the telecentric camera 2.

[0054] As Figure 1 shown, the lateral adjustment table includes four bearing platforms 4. The four bearing platforms 4 surround the positioning ball 6 and are arranged in pairs opposite to each other. They can fix lenses of different sizes and shapes. At the same time, the bearing platforms 4 arranged in pairs opposite to each other can provide height differences in different directions, facilitating the calibration of the pitch angle of the pitch adjustment table 7 to ensure that when the lens to be measured is fixed on the lens fixture plane 5, the reference axis of the lens to be measured is perpendicular to the imaging plane of the telecentric camera 2, thereby ensuring the stability and accuracy during the detection process.

[0055] Specifically, the single-direction positioning accuracy of the displacement adjustment table 8 is less than or equal to 0.5 μm. The level of the single-direction positioning accuracy directly affects the accuracy of the final position of the displacement adjustment table 8. Limiting it to a high precision can effectively reduce the error accumulation caused by multiple movements and improve the accuracy and reliability of positioning.

[0056] Specifically, the repeat positioning accuracy of the displacement adjustment table 8 is less than or equal to 0.1 μm. When performing repeated operations, such as moving to the same position multiple times for measurement, a high repeat positioning accuracy can ensure that the obtained positions are consistent each time, avoiding measurement errors caused by position changes.

[0057] By restricting the high-precision adjustment of the displacement adjustment table 8, precise movement of the lens in the xy plane is achieved, the position stability of the lens to be measured during the detection process is significantly improved, the error of repeated detection is extremely small, and the accuracy and reliability of the reference axis positioning of the lens to be measured are ensured.

[0058] Specifically, the step of the lifting table 1 is less than or equal to 2 μm, which can ensure that the lifting table 1 can achieve very fine control when adjusting the height, more accurately adjust the relative height between the telecentric camera 2 and the lens to be measured. In addition, the smaller step value helps to find the best focus position more precisely. Especially when using a high-magnification telecentric camera 2, it can ensure that the edge image of the lens to be measured is in the clearest state, which is very important for the eccentricity detection and reference axis positioning of the lens.

[0059] Specifically, the repeat positioning accuracy of the lifting table 1 is less than or equal to 1 μm, ensuring that the lifting table 1 can achieve extremely high position consistency when returning to the same position multiple times, and does not require frequent position calibration, which can save calibration time and cost.

[0060] By restricting the step and repeat positioning accuracy of the lifting table 1, it is ensured that the distance between the lens to be measured and the telecentric camera 2 is precisely controllable, improving the detection accuracy.

[0061] Specifically, the object space resolution of the telecentric camera 2 is less than or equal to 1 μm. The object space resolution represents the smallest object space detail size that the telecentric camera 2 can clearly image. By restricting and optimizing the object space resolution, the telecentric camera 2 can more accurately identify the contour of the edge of the lens to be measured.

[0062] Specifically, the depth of field of the telecentric camera 2 is less than or equal to 10 μm. Restricting the depth of field of the telecentric camera 2 to a very small value can ensure that the clearest image of the edge contour of the lens to be measured is captured within a small distance, thereby improving the detection accuracy.

[0063] Specifically, the detection error of the telecentric camera 2 is less than or equal to 1 μm. The low detection error helps to more accurately identify the edge of the lens to be measured and achieve sub-micron-level reference axis positioning. It also reduces data deviation caused by equipment instability or external interference, ensuring the consistency and reliability of the measurement data.

[0064] By restricting the object space resolution, depth of field and detection error of the telecentric camera 2, it is ensured that the high-precision imaging of the edge contour of the lens to be measured is achieved, improving the detection accuracy.

[0065] Specifically, the spatial angle between the side surface and the top surface of the supporting table 4 is in the range of 90 ± 0.5°, which can ensure that the contact surface between the lens to be measured and the supporting table 4 is perpendicular when placed, precisely control the placement posture of the lens to be measured, and at the same time reduce the displacement or tilt of the lens to be measured during the detection process, thereby improving the stability of positioning.

[0066] Specifically, the straightness error of the side of the bearing platform 4 is less than or equal to 10 μm. If the straightness error of the side of the bearing platform 4 is too high, the lens to be measured may be placed irregularly on the bearing platform 4, resulting in deviation in the positioning of the lens to be measured relative to the telecentric camera 2. Limiting the straightness error can ensure that the lens to be measured is placed more accurately on the bearing platform 4, reduce the error in the positioning process, and improve the positioning accuracy of the reference axis.

[0067] The present application also provides a method for positioning the reference axis of a lens. The spatial position of the reference axis of the lens to be measured is positioned by using the above-mentioned lens reference axis positioning platform. The method for positioning the reference axis of the lens includes: Step S10: Obtain the lens to be measured; Step S20: Calibrate the mapping relationship between the image coordinate system of the telecentric camera 2 of the lens reference axis positioning platform and the physical space coordinate system of the lateral adjustment table of the lens reference axis positioning platform according to the shape of the lens to be measured; Step S30: Determine the fitting position of the outer shape reference line of the lens to be measured in the physical space coordinate system according to the mapping relationship; Step S40: Obtain the preset relationship between the reference axis and the outer shape reference line of the lens to be measured; Step S50: Solve the spatial position of the reference axis in the physical space coordinate system according to the fitting position and the preset relationship.

[0068] Through Step S10 and Step S20, the mapping relationship between the image coordinate system of the telecentric camera 2 and the physical space coordinate system of the lateral adjustment table is calibrated, which is convenient for subsequent Step S30 to convert the outer shape reference line of the lens to be measured to the physical space coordinate system of the lateral adjustment table after imaging by the telecentric camera 2, and fit the actual outer shape reference line. Through Step S40 and Step S50, using the relationship between the reference axis and the outer shape reference line specified in the lens design stage, and according to the spatial position of the obtained outer shape reference line, the spatial position of the reference axis can be solved. The present application collects data on the outer shape reference line of the lens to be measured through a high-precision vision system, and combines a nanometer-level precision positioning platform to achieve a full-range scan of the outer shape reference line of the lens to be measured, thereby realizing the positioning of the reference axis of the lens to be measured in three-dimensional space.

[0069] Specifically, in the process of calibrating the mapping relationship between the image coordinate system of the telecentric camera 2 of the lens reference axis positioning platform and the physical space coordinate system of the lateral adjustment table of the lens reference axis positioning platform according to the shape of the lens to be measured, it includes: Imaging the positioning ball 6 through the telecentric camera 2 to obtain the position of the positioning ball 6 in the physical space coordinate system at (x stage , y stage ) and the position of the center of the ball of the positioning ball 6 on the image coordinate system at (x img , y img ); Adjust the position of the positioning ball 6 of the lens reference axis positioning platform to obtain the corresponding center coordinates of the positioning ball 6 at different positions; Calculate the image coordinate system Img(x img , y img)Mapping relationship with respect to the physical space coordinate system Stage(x stage , y stage ). By obtaining the center coordinates of the positioning ball 6 corresponding to different positions, the mapping relationship between the image coordinate system of the telecentric camera 2 and the physical space coordinate system of the transverse adjustment stage can be calibrated, and further, in actual lens detection, it can be used to position the lens reference axis within the spatial coordinate system range of the current transverse adjustment stage.

[0070] Specifically, in the process of adjusting the position of the positioning ball 6 of the lens reference axis positioning platform and obtaining the center coordinates of the positioning ball 6 corresponding to different positions, it includes: adjusting the displacement adjustment stage 8 and the lifting stage 1 of the transverse adjustment stage so that the positioning ball 6 is imaged at the center of the field of view of the telecentric camera 2; recording the coordinates (x stage0 , y stage0 ) of the displacement adjustment stage 8 in the physical space coordinate system and the coordinates (x img0 , y img0 ) of the center of the positioning ball 6 on the image coordinate system; adjusting the displacement adjustment stage 8 to move to the coordinates (x stage1 , y stage0 ), (x stage2 , y stage0 ), (x stage0 , y stage1 ), (x stage0 , y stage2 ) of the physical space coordinate system respectively, and recording the coordinates (x img1 , y img1 ), (x img2 , y img2 ), (x img3 , y img3 ), (x img4 , y img4 ) of the center of the positioning ball 6 on the image coordinate system respectively, where x stage1 = x stage0 + 5μm, x stage2 = x stage0 + 10μm, y stage1 = y stage0 + 5μm, y stage2 = x stage0 + 10μm. By driving the positioning ball 6 to move along a determined direction and distance through the displacement adjustment stage 8, it is convenient to locate and track the coordinates of the positioning ball 6 in the physical space coordinate system. At the same time, by controlling the lifting stage 1 to drive the telecentric camera 2 to clearly image the positioning ball 6, the accuracy of the coordinates of the center of the positioning ball 6 on the image coordinate system is ensured, thereby ensuring the accuracy of solving the mapping relationship and improving the accuracy of solving the reference axis.

[0071] Specifically, calculating the image coordinate system Img(x img , y img)During the process of the mapping relationship with respect to the physical space coordinate system Stage(x stage , y stage ), it includes: Img(x img , y img ) and Stage(x stage , y stage ) satisfy formulas (10) and (20):

[0072]

[0073] Among them, the calibration coefficient β is the linear magnification coefficient between the image coordinate system and the physical space coordinate system, the calibration coefficient R is the relative rotation matrix between the image coordinate system and the physical space coordinate system, and the calibration coefficient T is the relative offset matrix between the image coordinate system and the physical space coordinate system. Due to the relative magnification, rotation, and offset between the two coordinate systems, obtaining the calibration coefficient β, the calibration coefficient R, and the calibration coefficient T through formulas (10) and (20) can achieve the conversion from the image coordinate system to the physical space coordinate system, ensuring the subsequent accurate solution of the spatial position of the outer shape reference line of the lens to be measured.

[0074] Specifically, before the process of calibrating the mapping relationship between the image coordinate system of the telecentric camera 2 on the lens reference axis positioning platform and the physical space coordinate system of the lateral adjustment table of the lens reference axis positioning platform according to the shape of the lens to be measured, it also includes: calibrating that the bearing table 4 of the lateral adjustment table is horizontal relative to the imaging plane of the telecentric camera 2. Calibrating the bearing table 4 and the telecentric camera 2 in advance can ensure that the reference axis is perpendicular to the imaging plane of the telecentric camera 2 after placing the lens to be measured, reducing the inclination when placing the lens to be measured, so as to accurately detect the outer shape reference line of the lens to be measured and solve the accurate position of the reference axis, improving the accuracy and consistency of reference axis positioning.

[0075] Specifically, the number of bearing tables 4 is four. The four bearing tables 4 are the first bearing table to the fourth bearing table respectively. During the process of calibrating that the bearing table 4 of the lateral adjustment table is horizontal relative to the imaging plane of the telecentric camera 2, it includes: according to the shape of the lens to be measured, adjusting the positions of the four bearing tables 4 so that all bearing tables 4 are in contact with the bearing surface of the lens to be measured; adjusting the displacement adjustment table 8 of the lateral adjustment table so that the first bearing table is imaged at the center of the field of view of the telecentric camera 2; adjusting the height of the lifting table 1 of the lens reference axis positioning platform, and recording the height Z of the lifting table 1 when the edge contour image of the first bearing table is the clearest 1 ; respectively recording the height Z of the lifting table 1 when the edge contour images corresponding to the second bearing table to the fourth bearing table are the clearest when imaged at the center of the field of view of the telecentric camera 2 2 to Z 4 ; calculating the height difference Z 1 -Z 2 and the height difference Z 3-Z 4 ; Adjust the pitching adjustment table 7 of the horizontal adjustment table, repeat the measurement and calculate the height difference Z 1- Z 2 and the height difference Z 3 -Z 4 until |Z 1 -Z 2 | ≤ 10 μm, |Z 3 -Z 4 | ≤ 10 μm. Using the principle of the imaging defocus curve, the position of the telecentric camera 2 can be finely adjusted by the change in the clarity of the edge contour of the supporting table 4 to ensure that the imaging reaches the clearest state, thereby improving the measurement accuracy. The first to fourth supporting tables are clearly imaged at the center of the field of view of the telecentric camera 2 in sequence, ensuring the height Z 1 to Z 4 of the lifting table 1, and the accuracy and reliability of the data. By calculating the height differences Z 1- Z 2 、Z 3 -Z 4 of different orientations on the horizontal adjustment table relative to the telecentric camera 2, the current height difference can directly indicate the different distance differences of different supporting tables 4 relative to the plane of the telecentric camera 2. By adjusting the pitching adjustment table 7, finally achieve |Z 1 -Z 2 | ≤ 10 μm, |Z 3 -Z 4 | ≤ 10 μm, which can ensure that when the lens to be measured is placed between the supporting tables 4, the outer shape reference line of the lens to be measured is kept relatively horizontal with the imaging plane of the telecentric camera 2.

[0076] Specifically, in the process of determining the fitting position of the outer shape reference line of the lens to be measured in the physical space coordinate system according to the mapping relationship, it includes: fitting and fixing the bearing surface of the lens to be measured with the side surface of the supporting table 4; obtaining the first outer shape reference and the second outer shape reference of the lens to be measured; calculating the first outer shape equation Fa on the physical space coordinate system corresponding to the first outer shape reference and the second outer shape equation Fb on the physical space coordinate system corresponding to the second outer shape reference according to the mapping relationship. By converting two different first outer shape references and second outer shape references from the image coordinate system to the physical space coordinate system and determining their spatial positions, the first outer shape equation Fa and the second outer shape equation Fb, the spatial positioning of the lens to be measured is realized, and the high-precision reference axis positioning is further ensured.

[0077] Such as Figure 3As shown, in the process of calculating the first profile equation Fa in the physical space coordinate system corresponding to the first profile reference A and the second profile equation Fb in the physical space coordinate system corresponding to the second profile reference B according to the mapping relationship, it includes: adjusting the displacement adjustment stage 8 and the lifting stage 1 to make the first profile reference A clearly imaged in the telecentric camera 2, and recording the coordinates (x stage_a , y stage_a ) of the displacement adjustment stage 8; calculating the coordinate sets (x img_a1 , y img_a1 ) to (x img_an , y img_an ) of N points on the edge of the first profile reference A in the image coordinate system; according to the calibration coefficient β, the calibration coefficient R, and the calibration coefficient T, using formula (30) to convert the coordinate sets (x img_a1 , y img_a1 ) to (x img_an , y img_an ) into the coordinate sets (x stage_a1 , y stage_a1 ) to (x stage_an , y stage_an ) in the physical space coordinate system,

[0078]

[0079] According to the coordinate sets (x stage_a1 , y stage_a1 ) to (x stage_an , y stage_an ), fitting and calculating the first profile equation Fa.

[0080] The process of calculating the first profile equation Fa is to adjust the displacement adjustment stage 8 and the lifting stage 1 to ensure that the first profile reference A of the lens to be measured is clearly imaged in the telecentric camera 2, then obtain the image coordinates of N points through edge detection, convert them to the physical space coordinate system using the calibrated mapping relationship, and combine the shape features such as straight lines, curves, and feature points of the first profile reference A to determine the equation form of the first profile reference A and fit the actual spatial position of the first profile reference A in the physical space coordinate system.

[0081] As Figure 3 shown, in the process of calculating the first profile equation Fa in the physical space coordinate system corresponding to the first profile reference A and the second profile equation Fb in the physical space coordinate system corresponding to the second profile reference B according to the mapping relationship, it also includes: adjusting the displacement adjustment stage 8 and the lifting stage 1 to make the second profile reference B clearly imaged in the telecentric camera 2, and recording the coordinates (x stage_b , y stage_b ) of the displacement adjustment stage 8; calculating the coordinate sets (x img_b1 , yimg_b1 ) to (x img_bn , y img_bn ); According to the calibration coefficients β, R, and T, use formula (40) to convert the coordinate set (x img_b1 , y img_b1 ) to (x img_bn , y img_bn ) into the coordinate set (x stage_b1 , y stage_b1 ) to (x stage_bn , y stage_bn ) in the physical space coordinate system,

[0082]

[0083] According to the coordinate set (x stage_b1 , y stage_b1 ) to (x stage_bn , y stage_bn ), fit and calculate the second outer shape equation Fb.

[0084] Similar to the process of calculating the first outer shape equation Fa, the process of calculating the second outer shape equation Fb is to ensure that the second outer shape reference B of the lens to be measured is clearly imaged in the telecentric camera 2 by adjusting the displacement adjustment stage 8 and the lifting stage 1, then obtain the image coordinates of N points through edge detection, convert them to the physical space coordinate system using the calibrated mapping relationship, and combine the shape features such as the straight line, curve, and feature points of the second outer shape reference B to determine the equation form of the second outer shape reference B and fit the actual spatial position of the second outer shape reference B in the physical space coordinate system.

[0085] Specifically, in the process of obtaining the preset relationship between the reference axis and the outer shape reference line of the lens to be measured, it includes: obtaining the processing drawing of the lens to be measured; determining the distance La between the reference axis of the lens to be measured and the first outer shape reference A; determining the distance Lb between the reference axis of the lens to be measured and the second outer shape reference B. By obtaining the relationship between the reference axis and the outer shape reference line specified in the design stage of the lens to be measured, the position of the reference axis that satisfies the preset relationship can be solved according to the obtained first outer shape equation Fa and second outer shape equation Fb. Of course, the processing drawing can be automatically read by software and relevant parameters can be calculated, reducing the time of manual participation and adjustment and improving the efficiency of the entire positioning process.

[0086] Specifically, in the process of solving the spatial position of the reference axis in the physical space coordinate system according to the fitting position and the preset relationship, it includes: solving the point coordinates (x stage_cen , y stage_cen ) such that it simultaneously satisfies that the distance to the first outer shape equation Fa is La and the distance to the second outer shape equation Fb is Lb, and the point coordinates (x stage_cen , y stage_cen) is the position of the reference axis in the physical space coordinate system. As Figure 3 shown, find the point coordinates (x stage_cen , y stage_cen ) that satisfy the distance La from the first profile equation Fa and the distance Lb from the second profile equation Fb, that is, find the point where the reference axis passes through the plane of this coordinate system. The straight line perpendicular to this coordinate system plane and passing through this point is the straight line where the reference axis is located, thereby determining the position of the reference axis.

[0087] Through the method for positioning the reference axis of the lens of the present application, the spatial position of the reference axis of the optical lens can be positioned on the positioning platform, and can be further integrated into the lens eccentricity detection system to provide an eccentricity reference, or integrated into the lens assembly system to provide an assembly reference positioning. At the same time, the above-mentioned lens reference axis detection and positioning process is combined with software to realize an automatic process, which can greatly improve the positioning efficiency. In addition, the current positioning method has low requirements for the accuracy of the positioning platform and can be adapted to different lenses, improving the versatility of the positioning method and the positioning platform.

[0088] Obviously, the above-described embodiments are only a part of the embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0089] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular forms are also intended to include the plural forms. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0090] It should be noted that the terms "first", "second", etc. in the description, claims and drawings of the present application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged under appropriate circumstances so that the embodiments of the present application described herein can be implemented in an order different from those illustrated or described herein.

[0091] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A lens reference axis positioning platform, characterized in that: include: A lateral adjustment platform, the lateral adjustment platform comprising a plurality of adjustable support platforms (4), the support platforms (4) being used to fix the lens to be tested, the lateral adjustment platform being able to move in an xy plane and adjust a pitch angle relative to the xy plane; A lifting platform (1), the lifting platform (1) being arranged above the lateral adjustment platform at a distance, the lifting platform (1) being able to approach or move away from the lateral adjustment platform along an extension direction of a z-axis, the z-axis being perpendicular to the xy plane; A telecentric camera (2), the telecentric camera (2) being fixed on the lifting platform (1), and the telecentric camera (2) being used to detect the outer shape reference position of the lens to be tested; A positioning ball (6), wherein the positioning ball (6) is fixed on the lateral adjustment platform so that the telecentric camera (2) can position the lateral adjustment platform.

2. The lens reference axis positioning platform according to claim 1, characterized in that: The lateral adjustment platform comprises: A displacement adjustment platform (8), wherein the displacement adjustment platform (8) is capable of translationally moving in the xy plane; A pitch adjustment platform (7), wherein the pitch adjustment platform (7) is fixed on the displacement adjustment platform (8), the pitch adjustment platform (7) is capable of adjusting the pitch angle relative to the xy plane, and the lens to be tested is fixed on the pitch adjustment platform (7).

3. The lens reference axis positioning platform according to claim 2, characterized in that: The pitch adjustment platform (7) has a lens fixture plane (5), and the supporting platform (4) and the positioning ball (6) are arranged on the lens fixture plane (5).

4. The lens reference axis positioning platform according to claim 3, characterized in that: The lens reference axis positioning platform also includes a point light source (3) arranged toward the lateral adjustment platform, the point light source (3) forms a coaxial optical path with the telecentric camera (2), and the lens fixture plane (5) and the top surface of the supporting platform (4) are capable of reflecting light emitted by the point light source (3).

5. The lens reference axis positioning platform according to claim 4, characterized in that: The positioning ball (6) is located at the center of the lens fixture plane (5).

6. The lens reference axis positioning platform according to claim 5, characterized in that: The lateral adjustment platform comprises four supporting platforms (4), and the four supporting platforms (4) surround the positioning ball (6) and are arranged opposite to each other in pairs.

7. The lens reference axis positioning platform according to claim 2, characterized in that: The one-way positioning accuracy of the displacement adjustment platform (8) is less than or equal to 0.5 μm; and / or The repeat positioning accuracy of the displacement adjustment platform (8) is less than or equal to 0.1 μm.

8. The lens reference axis positioning platform according to any one of claims 1 to 7, characterized in that: The stepping distance of the lifting platform (1) is less than or equal to 2 μm; and / or The repeated positioning accuracy of the lifting platform (1) is less than or equal to 1 μm.

9. The lens reference axis positioning platform according to any one of claims 1 to 7, characterized in that: The object-space resolution of the telecentric camera (2) is less than or equal to 1 μm; and / or The depth of field of the telecentric camera (2) is less than or equal to 10 μm; and / or The detection error of the telecentric camera (2) is less than or equal to 1 μm.

10. The lens reference axis positioning platform according to any one of claims 1 to 7, characterized in that: The spatial angle between the side surface of the supporting platform (4) and the top surface of the supporting platform (4) is within the range of 90±0.5°; and / or The side straightness error of the supporting platform (4) is less than or equal to 10 μm.

11. A method for positioning a reference axis of a lens, characterized in that: The lens reference axis positioning platform according to any one of claims 1 to 10 is used to position the spatial position of the reference axis of the lens to be tested, and the lens reference axis positioning method comprises: Obtain the lens to be tested; Calibrate the mapping relationship between the image coordinate system of the telecentric camera of the lens reference axis positioning platform and the physical space coordinate system of the lateral adjustment platform of the lens reference axis positioning platform according to the shape of the lens to be tested; Determining the fitting position of the outline reference line of the lens to be tested in the physical space coordinate system according to the mapping relationship; Obtaining a preset relationship between the reference axis of the lens to be tested and the profile reference line; The spatial position of the reference axis in the physical space coordinate system is solved according to the fitting position and the preset relationship.

12. The lens reference axis positioning method according to claim 11, characterized in that: The process of calibrating the mapping relationship between the image coordinate system of the telecentric camera of the lens reference axis positioning platform and the physical space coordinate system of the lateral adjustment platform of the lens reference axis positioning platform according to the shape of the lens to be tested includes: The positioning ball is imaged by the telecentric camera, and the position of the positioning ball in the physical space coordinate system is obtained. stage ,y stage ) is the position (x) of the center of the positioning ball on the image coordinate system img ,y img ); Adjust the position of the positioning ball of the lens reference axis positioning platform to obtain the corresponding spherical center coordinates of the positioning ball at different positions; Calculate the image coordinate system Img(x img ,y img ) relative to the physical space coordinate system Stage(x stage ,y stage )’s mapping relationship.

13. The lens reference axis positioning method according to claim 12, characterized in that: The process of adjusting the position of the positioning ball of the lens reference axis positioning platform and obtaining the corresponding spherical center coordinates of the positioning ball at different positions includes: Adjusting the displacement adjustment platform of the lateral adjustment platform and the lifting platform so that the positioning ball is imaged at the center of the field of view of the telecentric camera; Record the coordinates (x stage0 ,y stage0 ) and the coordinates (x img0 ,y img0 ); Adjust the displacement adjustment platform to move to the coordinates (x stage1 ,y stage0 )、(x stage2 ,y stage0 )、(x stage0 ,y stage1 )、(x stage0 ,y stage2 ), respectively record the coordinates (x img1 ,y img1 )、(x img2 ,y img2 )、(x img3 ,y img3 )、(x img4 ,y img4 ), where x stage1 =x stage0 +5μm, x stage2 =x stage0 +10μm,y stage1 =y stage0 +5μm, y stage2 =x stage0 +10μm.

14. The lens reference axis positioning method according to claim 13, characterized in that: The calculation of the image coordinate system Img(x img ,y img ) relative to the physical space coordinate system Stage(x stage ,y stage ) in the process of mapping relationship, including: The Img(x img ,y img ) and the Stage(x stage ,y stage ) satisfies formula (10) and formula (20): Among them, the calibration coefficient β is the linear magnification coefficient of the image coordinate system and the physical space coordinate system, the calibration coefficient R is the relative rotation matrix between the image coordinate system and the physical space coordinate system, and the calibration coefficient T is the relative offset matrix between the image coordinate system and the physical space coordinate system.

15. The lens reference axis positioning method according to claim 11, characterized in that: Before the process of calibrating the mapping relationship between the image coordinate system of the telecentric camera of the lens reference axis positioning platform and the physical space coordinate system of the lateral adjustment platform of the lens reference axis positioning platform according to the shape of the lens to be tested, it also includes: calibrating the relative level of the supporting platform of the lateral adjustment platform and the imaging plane of the telecentric camera.

16. The lens reference axis positioning method according to claim 15, characterized in that: The number of the supporting platforms is four, and the four supporting platforms are respectively the first supporting platform to the fourth supporting platform. The process of calibrating the supporting platform of the lateral adjustment platform and the imaging plane of the telecentric camera to be relatively level includes: According to the shape of the lens to be tested, the positions of the four supporting platforms are adjusted so that all the supporting platforms are in contact with the supporting surface of the lens to be tested; Adjusting the displacement adjustment stage of the lateral adjustment stage so that the first supporting stage is imaged at the center of the field of view of the telecentric camera; Adjust the height of the lifting platform of the lens reference axis positioning platform, and record the height Z1 of the lifting platform when the edge contour image of the first supporting platform is clearest; Record the heights Z2 to Z4 of the lifting platform when the edge contour images corresponding to the imaging of the center of the field of view of the telecentric camera from the second supporting platform to the fourth supporting platform are clearest respectively; Calculate the height difference Z1-Z2 and the height difference Z3-Z4; Adjust the pitch adjustment platform of the lateral adjustment platform, and repeat the measurement and calculation of the height difference Z 1- Z2 and the height difference Z3-Z4, until |Z1-Z2|≤10μm, |Z3-Z4|≤10μm.

17. The lens reference axis positioning method according to claim 14, characterized in that: The process of determining the fitting position of the outer shape reference line of the lens to be tested in the physical space coordinate system according to the mapping relationship includes: The supporting surface of the lens to be tested is fitted and fixed to the side surface of the supporting platform; Acquire a first shape reference and a second shape reference of the lens to be tested; According to the mapping relationship, a first shape equation Fa on the physical space coordinate system corresponding to the first shape reference and a second shape equation Fb on the physical space coordinate system corresponding to the second shape reference are calculated.

18. The lens reference axis positioning method according to claim 17, characterized in that: The process of calculating the first shape equation Fa on the physical space coordinate system corresponding to the first shape reference and the second shape equation Fb on the physical space coordinate system corresponding to the second shape reference according to the mapping relationship includes: Adjust the displacement adjustment platform and the lifting platform so that the first shape reference is clearly imaged in the telecentric camera, and record the coordinates (x stage_a ,y stage_a ); Calculate the coordinate set (x img_a1 ,y img_a1 )~(x img_an ,y img_an ); According to the calibration coefficient β, the calibration coefficient R and the calibration coefficient T, the coordinate set (x img_a1 ,y img_a1 )~(x img_an ,y img_an ) is converted into the coordinate set (x stage_a1 ,y stage_a1 )~(x stage_an ,y stage_an ), According to the coordinate set (x stage_a1 ,y stage_a1 )~(x stage_an ,y stage_an ), fitting and calculating the first shape equation Fa.

19. The lens reference axis positioning method according to claim 18, characterized in that: The process of calculating the first shape equation Fa on the physical space coordinate system corresponding to the first shape reference and the second shape equation Fb on the physical space coordinate system corresponding to the second shape reference according to the mapping relationship also includes: Adjust the displacement adjustment platform and the lifting platform so that the second shape reference is clearly imaged in the telecentric camera, and record the coordinates (x stage_b ,y stage_b ); Calculate the coordinate set (x img_b1 ,y img_b1 )~(x img_bn ,y img_bn ); According to the calibration coefficient β, the calibration coefficient R and the calibration coefficient T, the coordinate set (x img_b1 ,y img_b1 )~(x img_bn ,y img_bn ) is converted into the coordinate set (x stage_b1 ,y stage_b1 )~(x stage_bn ,y stage_bn ), According to the coordinate set (x stage_b1 ,y stage_b1 )~(x stage_bn ,y stage_bn ), fit and calculate the second shape equation Fb.

20. The lens reference axis positioning method according to claim 19, characterized in that: The process of obtaining the preset relationship between the reference axis of the lens to be tested and the profile reference line includes: Obtaining a processing drawing of the lens to be tested; Determine the distance La between the reference axis of the lens to be tested and the first shape reference; Determine the distance Lb between the reference axis of the lens to be tested and the second shape reference.

21. The lens reference axis positioning method according to claim 20, characterized in that: The process of solving the spatial position of the reference axis in the physical space coordinate system according to the fitting position and the preset relationship includes: Solve for the coordinates of the point (x stage_cen ,y stage_cen ), so that it satisfies the distance to the first shape equation Fa as La, the distance to the second shape equation Fb as Lb, and the point coordinates (x stage_cen ,y stage_cen ) is the position of the reference axis in the physical space coordinate system.

Images