Lens reference axis positioning platform

Abstract

The utility model provides a lens reference axis positioning platform which comprises the components of a transverse adjusting platform which comprises a plurality of bearing platforms which are adjustably arranged, the bearing platforms are used for fixing a to-be-measured lens, and the transverse adjusting platform can move in an xy plane and adjust a 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. According to the utility model, the problems of low positioning precision of the lens reference axis and poor universality of the jig in the prior art are solved.

Description

Technical Field

[0001] This utility model relates to the field of lens eccentricity detection technology, and more specifically, to a lens reference axis positioning platform. Background Technology

[0002] In the production, inspection, and assembly of optical lenses, the positioning of the lens's reference axis is a crucial step in ensuring the lens's optical performance and mechanical assembly accuracy. The detection and assembly of lens eccentricities must be performed with reference to the lens's reference axis. Typically, the lens's reference axis is defined by the mechanical center and external datum established during the lens design and manufacturing stages. However, existing lens eccentricity detection systems and assembly processes have several limitations in their reference axis positioning methods.

[0003] Currently, lens eccentricity detection systems typically employ custom-designed high-precision fixtures to position the lens's reference axis. These fixtures require precise matching of the lens's mechanical center and external reference dimensions, while also incorporating high-precision feature points for positioning the eccentricity detection probe. Although this method provides high positioning accuracy, a dedicated fixture needs to be designed and manufactured for each lens, resulting in high costs, long processing cycles, and poor fixture versatility. Especially when dealing with lenses of different sizes and shapes, fixture replacement and adjustment become complex, reducing production efficiency.

[0004] Furthermore, traditional positioning methods require extremely high precision fixtures; even the slightest manufacturing error or misalignment between the lens and the fixture can directly affect the accuracy of the reference axis positioning. In large-scale production environments, fixture recalibration and maintenance are also time-consuming and costly processes, further limiting the flexibility and efficiency of the positioning system.

[0005] In other words, existing technologies suffer from low precision in lens reference axis positioning and poor fixture versatility. Utility Model Content

[0006] The main purpose of this invention is to provide a lens reference axis positioning platform to solve the problems of low positioning accuracy of lens reference axes and poor versatility of fixtures in the prior art.

[0007] To achieve the above objectives, according to one aspect of the present invention, a lens reference axis positioning platform is provided, comprising: a lateral adjustment platform, the lateral adjustment platform including a plurality of adjustable support platforms for fixing the lens to be tested, the lateral adjustment platform being movable in the xy plane and adjustable in pitch angle relative to the xy plane; a lifting platform, the lifting platforms being spaced above the lateral adjustment platform, the lifting platforms being able to move closer to or further away from the lateral adjustment platform along the extension direction of the z-axis, the z-axis being perpendicular to the xy plane; a telecentric camera, the telecentric camera being fixed on the lifting platform, the telecentric camera being used to detect the morphological reference position of the lens to be tested; and a positioning ball, the positioning ball being fixed on the lateral adjustment platform so that the telecentric camera can position the lateral adjustment platform.

[0008] Furthermore, the lateral adjustment stage includes: a displacement adjustment stage, which can translate within the xy plane; and a pitch adjustment stage, which is fixed on the displacement adjustment stage and can adjust the pitch angle relative to the xy plane, with the lens under test fixed on the pitch adjustment stage.

[0009] Furthermore, the pitch adjustment platform has a lens fixture plane, and the support platform and positioning ball are set on the lens fixture plane.

[0010] Furthermore, the lens reference axis positioning platform also includes a point light source positioned towards the lateral adjustment stage. The point light source and the telecentric camera form a coaxial optical path, and the lens fixture plane and the top surface of the support stage can reflect the light emitted by the point light source.

[0011] Furthermore, the positioning ball is located at the center of the lens fixture plane.

[0012] Furthermore, the lateral adjustment platform includes four support platforms, which surround the positioning ball and are arranged in pairs opposite to each other.

[0013] Furthermore, the unidirectional positioning accuracy of the displacement adjustment stage is less than or equal to 0.5 μm; and / or the repeatability of the displacement adjustment stage is less than or equal to 0.1 μm.

[0014] Furthermore, the step size of the lifting platform is less than or equal to 2 μm; and / or the repeatability of the lifting platform is less than or equal to 1 μm.

[0015] Furthermore, the object-space 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] Furthermore, the spatial angle between the side surface and the top surface of the support platform is within the range of 90±0.5°; and / or the straightness error of the side surface of the support platform is less than or equal to 10μm.

[0017] According to another aspect of this utility model, a lens reference axis positioning method is provided. The method uses the aforementioned lens reference axis positioning platform to locate the spatial position of the reference axis of the lens under test. The lens reference axis positioning method includes: acquiring the lens under test; 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 stage of the lens reference axis positioning platform according to the shape of the lens under test; determining the fitting position of the outer contour baseline of the lens under test in the physical space coordinate system according to the mapping relationship; acquiring a preset relationship between the reference axis and the outer contour baseline of the lens under test; and solving for the spatial position of the reference axis in the physical space coordinate system based on the fitting position and the preset relationship.

[0018] Furthermore, in the process of determining 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 transverse adjustment stage of the lens reference axis positioning platform, based on the shape of the lens under test, the process includes: imaging the positioning sphere with the telecentric camera to obtain the position of the positioning sphere in the physical space coordinate system at (x... stage y stage The position (x, y) of the center of the sphere in the image coordinate system at that time. img y img Adjust the position of the positioning ball on the lens reference axis positioning platform to obtain the 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 The mapping relationship of ).

[0019] Furthermore, the process of adjusting the position of the positioning ball on the lens reference axis positioning platform and obtaining the center coordinates of the positioning ball at different positions includes: adjusting the displacement adjustment platform and the lifting platform of the lateral adjustment stage to make the positioning ball imaged at the center of the field of view of the telecentric camera; and recording the coordinates (x, y) of the displacement adjustment platform in the physical space coordinate system. stage0 y stage0 ) and the coordinates (x, y) of the center of the positioning sphere in the image coordinate system. img0 y img0 ); Adjust the displacement adjustment platform to move to the coordinates (x, y) of the physical space coordinate system. stage1 y stage0 ), (x stage2 y stage0 ), (x stage0 y stage1 ), (x stage0 y stage2 Record the coordinates (x, y) of the center of the positioning sphere in the image coordinate system. 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] Furthermore, the image coordinate system Img(x) is calculated. img y img Relative to the physical space coordinate system Stage(x) stage y stage The mapping process includes: Img(x) img y img ) and Stage(x stage y stage The following conditions must be met between the given conditions: (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] Furthermore, before determining 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 stage of the lens reference axis positioning platform, based on the shape of the lens to be tested, the process also includes: determining the relative horizontality between the support platform of the lateral adjustment stage and the imaging plane of the telecentric camera.

[0024] Furthermore, there are four support platforms, designated as the first to fourth support platforms. The process of calibrating the horizontal adjustment platform to ensure its relative horizontality with the telecentric camera's imaging plane includes: adjusting the positions of the four support platforms according to the shape of the lens under test, ensuring all platforms are in contact with the support surface of the lens; adjusting the displacement adjustment platform of the horizontal adjustment platform to ensure the first support platform is imaged at the center of the telecentric camera's field of view; adjusting the height of the lifting platform of the lens reference axis positioning platform, and recording the height Z1 when the edge contour image of the first support platform is clearest; recording the heights Z2 to Z4 when the edge contour images of the second to fourth support platforms are clearest at the center of the telecentric camera's field of view; calculating the height differences Z1-Z2 and Z3-Z4; adjusting the pitch adjustment platform of the horizontal adjustment platform, and repeatedly measuring and calculating the height difference Z. 1- Z2 and height difference Z3-Z4, until |Z1-Z2|≤10μm, |Z3-Z4|≤10μm.

[0025] Furthermore, in the process of determining the fitting position of the datum line of the lens under test in the physical space coordinate system according to the mapping relationship, the process includes: attaching and fixing the bearing surface of the lens under test to the side of the bearing platform; obtaining the first datum line and the second datum line of the lens under test; and calculating the first datum line equation Fa in the physical space coordinate system corresponding to the first datum line and the second datum line equation Fb in the physical space coordinate system corresponding to the second datum line according to the mapping relationship.

[0026] Furthermore, based on the mapping relationship, the process of calculating the first shape equation Fa in the physical space coordinate system corresponding to the first shape datum and the second shape equation Fb in the physical space coordinate system corresponding to the second shape datum includes: adjusting the displacement adjustment stage and the lifting stage to make the first shape datum clearly imaged in the telecentric camera, and recording the coordinates (x, y) of the displacement adjustment stage. stage_a y stage_a ); Calculate the set of coordinates (x, y) of N points on the edge of the first shape reference in the image coordinate system. img_a1 y img_a1 )~(x img_an y img_an ); Based on the calibration coefficients β, R, and T, the coordinate set (x) is calculated using formula (30). img_a1 y img_a1 )~(x img_an y img_an The set of coordinates (x) converted to the physical space coordinate system stage_a1 y stage_a1 )~(x stage_an y stage_an ),

[0027]

[0028] According to the coordinate set (x stage_a1 y stage_a1 )~(x stage_an y stage_an ), and the first shape equation Fa is calculated by fitting.

[0029] Furthermore, in the process of calculating the first shape equation Fa in the physical space coordinate system corresponding to the first shape datum and the second shape equation Fb in the physical space coordinate system corresponding to the second shape datum, based on the mapping relationship, the process also includes: adjusting the displacement adjustment stage and the lifting stage to make the second shape datum clearly imaged in the telecentric camera, and recording the coordinates (x, y) of the displacement adjustment stage. stage_b y stage_b ); Calculate the set of coordinates (x, y) of N points on the edge of the second shape reference in the image coordinate system. img_b1 y img_b1 )~(x img_bn y img_bn ); Based on the calibration coefficients β, R, and T, the coordinate set (x) is calculated using formula (40). img_b1 y img_b1 )~(x img_bn y img_bn The set of coordinates (x) converted to the physical space coordinate system stage_b1 y stage_b1 )~(x stage_bn y stage_bn ),

[0030]

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

[0032] Furthermore, the process of obtaining the preset relationship between the reference axis and the outer shape reference line of the lens under test includes: obtaining the processing drawing of the lens under test; determining the distance La of the reference axis of the lens under test relative to the first outer shape reference; and determining the distance Lb of the reference axis of the lens under test relative to the second outer shape reference.

[0033] Furthermore, in the process of solving the spatial position of the reference axis in the physical coordinate system based on the fitted position and the preset relationship, the following steps are taken: solving the point coordinates (x... stage_cen y stage_cen ), such that it simultaneously satisfies the following conditions: the distance to the first shape equation Fa is La, and the distance to the second 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.

[0034] The lens reference axis positioning platform, utilizing the technical solution of this utility model, includes a lateral adjustment platform, a lifting platform, a telecentric camera, and a positioning ball. The lateral adjustment platform includes multiple adjustable support platforms for fixing the lens under test. The lateral adjustment platform can move within the xy plane and adjust its pitch angle relative to the xy plane. The lifting platforms are spaced above the lateral adjustment platform and can move closer to or further away from the lateral adjustment platform along the extension direction of the z-axis, which is perpendicular to the xy plane. The telecentric camera is fixed on the lifting platform and is used to detect the lateral reference position of the lens under test. The positioning ball is fixed on the lateral adjustment platform so that the telecentric camera can position the lateral adjustment platform.

[0035] The lateral adjustment stage includes multiple adjustable support platforms for fixing lenses of different sizes and shapes, ensuring stability and accuracy during testing. The lateral adjustment stage can move and adjust its pitch angle within the xy-plane to accommodate the testing needs of different lenses. The lateral adjustment stage is calibrated to be relatively horizontal with respect to the telecentric camera plane, ensuring that the reference axis of the lens under test is perpendicular to the telecentric camera plane. This ensures accurate relative positioning between the lens and the telecentric camera. Lifting platforms are spaced above the lateral adjustment stage and can move closer to or further away from it along the z-axis, which is perpendicular to the xy-plane. By precisely controlling the movement of the lifting platforms, the distance between the telecentric camera and the lens under test can be adjusted, ensuring image clarity and accuracy. A positioning ball is fixed to the lateral adjustment stage, enabling the telecentric camera to position the stage. Precise imaging from the positioning ball allows for the calibration of the relative position between the telecentric camera and the lateral adjustment stage, thus establishing the mapping between the image coordinate system of the telecentric camera and the physical coordinate system of the lateral adjustment stage. Furthermore, in actual lens inspection, this can be used to position the lens under test within the spatial coordinate system of the current lateral adjustment stage. Additionally, the lens reference axis positioning platform of this application has low precision requirements for the lens fixture and can be adapted to different lenses, thus exhibiting high versatility. Attached Figure Description

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

[0037] Figure 1 A schematic diagram of the lens reference axis positioning platform according to an optional embodiment of the present invention is shown;

[0038] Figure 2 This diagram illustrates a calibration point marking of the image coordinate system and physical space coordinate system according to an optional embodiment of the present invention.

[0039] Figure 3 This invention illustrates a schematic diagram of the first and second external shape references and the reference axis markings in different coordinate systems, representing an optional embodiment of the present invention.

[0040] Figure 4 A flowchart of a lens reference axis positioning method according to any optional embodiment of the present invention is shown.

[0041] The above figures include the following reference numerals:

[0042] 1. Lifting platform; 2. Telecentric camera; 3. Point light source; 4. Support platform; 5. Lens fixture plane; 6. Positioning ball; 7. Pitch adjustment platform; 8. Displacement adjustment platform. Detailed Implementation

[0043] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0044] It should be noted that, unless otherwise specified, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0045] In this utility model, unless otherwise stated, directional terms such as "upper," "lower," "top," and "bottom" are generally used in relation to the direction shown in the accompanying drawings, or in relation to the vertical, perpendicular, or gravitational direction of the component itself; similarly, for ease of understanding and description, "inner" and "outer" refer to the inner and outer contours of each component itself, but the above directional terms are not used to limit this utility model.

[0046] To address the problems of low positioning accuracy and poor fixture versatility in existing technologies, this invention provides a lens reference axis positioning platform and a lens reference axis positioning method.

[0047] like Figures 1 to 4 As shown, the lens reference axis positioning platform includes a lateral adjustment platform, a lifting platform 1, a telecentric camera 2, and a positioning ball 6. The lateral adjustment platform includes multiple adjustable support platforms 4, which are used to fix the lens under test. The lateral adjustment platform can move in the xy plane and adjust its pitch angle relative to the xy plane. The lifting platforms 1 are spaced above the lateral adjustment platform. The lifting platforms 1 can move closer to or further away from the lateral adjustment platform along the extension direction of the z-axis, which is perpendicular to the xy plane. The telecentric camera 2 is fixed on the lifting platform 1 and is used to detect the reference position of the shape of the lens under test. The positioning ball 6 is fixed on the lateral adjustment platform so that the telecentric camera 2 can position the lateral adjustment platform.

[0048] The lateral adjustment stage includes multiple adjustable support platforms 4 for fixing lenses of different sizes and shapes, ensuring the stability and accuracy of the lenses during the testing process. The lateral adjustment stage can move and adjust its pitch angle within the xy-plane to adapt to the testing requirements of different lenses. The lateral adjustment stage is calibrated to be relatively horizontal with respect to the plane of the telecentric camera 2, ensuring that the reference axis of the lens under test is perpendicular to the plane of the telecentric camera 2. This ensures the accurate relative position of the lens and the telecentric camera 2. Lifting platforms 1 are spaced above the lateral adjustment stage and can move closer to or further away from it along the z-axis, which is perpendicular to the xy-plane. By precisely controlling the movement of the lifting platforms 1, the distance between the telecentric camera 2 and the lens under test can be adjusted, ensuring image clarity and accuracy. The positioning ball 6 is fixed on the lateral adjustment stage, enabling the telecentric camera 2 to position the lateral adjustment stage. Through the precise imaging of the positioning ball 6, the relative position between the telecentric camera 2 and the lateral adjustment stage can be calibrated, thereby establishing the mapping relationship between the image coordinate system of the telecentric camera 2 and the physical spatial coordinate system of the lateral adjustment stage. Furthermore, in actual lens inspection, this can be used to position the lens under test within the spatial coordinate system range of the current lateral adjustment stage. In addition, the lens reference axis positioning platform of this application has low precision requirements for the lens fixture and can be adapted to different lenses, thus possessing high versatility.

[0049] like Figure 1 As shown, the lateral 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 can adjust the pitch angle relative to the xy-plane. The lens under test is fixed on the pitch adjustment stage 7. The displacement adjustment stage 8, capable of translation within the xy-plane, provides precise horizontal movement for the lens under test. Simultaneously, the pitch adjustment stage 7, fixed on the displacement adjustment stage 8, can adjust the pitch angle relative to the xy-plane. The lens under test is fixed on it, and through the adjustment of the pitch adjustment stage 7, it is ensured that the lens under test remains relatively horizontal with the imaging plane of the telecentric camera 2, further improving detection accuracy.

[0050] like Figure 1 As shown, the lens reference axis positioning platform also includes a point light source 3 facing the transverse adjustment stage. The point light source 3 and the telecentric camera 2 form a coaxial optical path. The lens fixture plane 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 under test, thereby improving the detection accuracy.

[0051] like Figure 1As shown, the pitch adjustment stage 7 has a lens fixture plane 5, with a support platform 4 and a positioning ball 6 mounted on it. The design of the lens fixture plane 5 ensures the stable fixation of the support platform 4 and the positioning ball 6, while providing a smooth reflective surface. The top surfaces of the lens fixture plane 5 and the support platform 4 can reflect the light emitted by the point light source 3, aiding in positioning. The precise positioning of the support platform 4 and the positioning ball 6 enables the telecentric camera 2 to accurately detect the external reference of the lens under test and position the reference axis of the lens under test, improving the accuracy and efficiency of the detection.

[0052] like Figure 1 As shown, the positioning ball 6 is located at the center of the lens fixture plane 5, serving as a positioning reference point to calibrate the relative position between the telecentric camera 2 and the pitch adjustment stage 7, ensuring positioning accuracy during the testing process.

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

[0054] like Figure 1 As shown, the lateral adjustment stage includes four support platforms 4, which surround the positioning ball 6 and are arranged in pairs opposite each other. This allows for the fixing of lenses of different sizes and shapes. At the same time, the pairs of opposite support platforms 4 can provide height differences in different directions, which facilitates the calibration of the pitch angle of the pitch adjustment stage 7. This ensures that when the lens under test is fixed on the lens fixture plane 5, the reference axis of the lens under test is perpendicular to the imaging plane of the telecentric camera 2, thereby ensuring stability and accuracy during the testing process.

[0055] Specifically, the unidirectional positioning accuracy of the displacement adjustment stage 8 is less than or equal to 0.5 μm. The level of unidirectional positioning accuracy directly affects the accuracy of the final position of the displacement adjustment stage 8. Limiting it to a higher accuracy can effectively reduce the accumulation of errors caused by multiple movements, thereby improving the accuracy and reliability of positioning.

[0056] Specifically, the repeatability of the displacement adjustment stage 8 is less than or equal to 0.1 μm. During repetitive operations, such as moving to the same position multiple times for measurement, high repeatability ensures consistent positioning each time, avoiding measurement errors caused by positional changes.

[0057] By limiting the high-precision adjustment of the displacement adjustment stage 8, the lens can be moved accurately in the xy plane. The positional stability of the lens under test during the testing process is significantly improved, the error of repeated testing is minimal, and the accuracy and reliability of the reference axis positioning of the lens under test are ensured.

[0058] Specifically, the step size of the lifting platform 1 is less than or equal to 2μm, which ensures that the lifting platform 1 can achieve very fine control when adjusting the height, and more accurately adjust the relative height between the telecentric camera 2 and the lens under test. In addition, the smaller step size helps to find the optimal focus position more accurately, especially when using the high-magnification telecentric camera 2, which can ensure that the edge image of the lens under test is in the clearest state, which is very important for the eccentricity detection of the lens and the positioning of the reference axis.

[0059] Specifically, the repeatability of the lifting platform 1 is less than or equal to 1μm, ensuring that the lifting platform 1 can achieve extremely high positional consistency when returning to the same position multiple times, eliminating the need for frequent position calibration and saving calibration time and costs.

[0060] By limiting the stepping and repeatability accuracy of the lifting platform 1, the distance between the lens under test and the telecentric camera 2 is ensured to be precise and controllable, thereby improving the detection accuracy.

[0061] Specifically, the object-space resolution of telecentric camera 2 is less than or equal to 1 μm. Object-space resolution represents the smallest object-space detail size that telecentric camera 2 can clearly image. By limiting and optimizing the object-space resolution, telecentric camera 2 can more accurately identify the contours of the edge of the lens under test.

[0062] Specifically, the depth of field of the telecentric camera 2 is less than or equal to 10 μm. Limiting the depth of field of the telecentric camera 2 to a very small value ensures that the image with the clearest edge contour of the lens under test is captured at a small distance, thereby improving the accuracy of the detection.

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

[0064] By limiting the object-space resolution, depth of field, and detection error of the telecentric camera 2, high-precision imaging of the edge contour of the lens under test is ensured, thereby improving detection accuracy.

[0065] Specifically, the spatial angle between the side surface of the support platform 4 and the top surface of the support platform 4 is within the range of 90±0.5°, which can ensure that the lens under test is perpendicular to the contact surface of the support platform 4 when it is placed, accurately control the placement posture of the lens under test, and reduce the displacement or tilt of the lens under test during the testing process, thereby improving the stability of positioning.

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

[0067] This application also provides a lens reference axis positioning method, which uses the above-mentioned lens reference axis positioning platform to locate the spatial position of the reference axis of the lens under test. The lens reference axis positioning method includes: step S10: acquiring the lens under test; step S20: 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 stage of the lens reference axis positioning platform according to the shape of the lens under test; step S30: determining the fitting position of the outer contour baseline of the lens under test in the physical space coordinate system according to the mapping relationship; step S40: acquiring the preset relationship between the reference axis and the outer contour baseline of the lens under test; step S50: solving the spatial position of the reference axis in the physical space coordinate system according to the fitting position and the preset relationship.

[0068] Through steps S10 and S20, the mapping relationship between the image coordinate system of the telecentric camera 2 and the physical space coordinate system of the lateral adjustment stage is calibrated. This facilitates the subsequent transformation of the datum line of the lens under test into the physical space coordinate system of the lateral adjustment stage after imaging by the telecentric camera 2 in step S30, allowing for the fitting of the actual datum line. Through steps S40 and S50, utilizing the relationship between the reference axis and the datum line specified in the lens design stage, the spatial position of the reference axis can be calculated based on the spatial position of the obtained datum line. This application uses a high-precision vision system to acquire data of the datum line of the lens under test, and combines it with a nanometer-level precision positioning platform to achieve full-range scanning of the datum line of the lens under test, thereby realizing the positioning of the reference axis of the lens under test in three-dimensional space.

[0069] Specifically, in the process of determining 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 transverse adjustment stage of the lens reference axis positioning platform, based on the shape of the lens to be tested, the process includes: imaging the positioning sphere 6 through the telecentric camera 2 to obtain the position of the positioning sphere 6 in the physical space coordinate system at (x... stage y stage The position (x, y) of the center of sphere 6 in the image coordinate system. img y img Adjust the position of the positioning ball 6 on the lens reference axis positioning platform, and obtain the center coordinates of the positioning ball 6 at different positions; calculate the image coordinate system Img(x img y imgRelative to the physical space coordinate system Stage(x) stage y stage 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 by obtaining the center coordinates of the positioning ball 6 at different positions. This mapping relationship can be further used in actual lens inspection to position the lens reference axis within the current spatial coordinate system of the horizontal adjustment stage.

[0070] Specifically, the process of adjusting the position of the positioning ball 6 on the lens reference axis positioning platform and obtaining the center coordinates of the positioning ball 6 at different positions includes: adjusting the displacement adjustment stage 8 and the lifting stage 1 of the lateral adjustment stage so that the positioning ball 6 is imaged at the center of the field of view of the telecentric camera 2; and recording the coordinates (x, y) of the displacement adjustment stage 8 in the physical space coordinate system. stage0 y stage0 The coordinates (x, y) of the center of positioning sphere 6 in the image coordinate system. img0 y img0 ); Adjust the displacement adjustment platform 8 to move to the coordinates (x, y) of the physical space coordinate system. stage1 y stage0 ), (x stage2 y stage0 ), (x stage0 y stage1 ), (x stage0 y stage2 Record the coordinates (x, y) of the center of positioning sphere 6 in the image coordinate system. 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. The positioning ball 6 is moved along a defined direction and distance by the displacement adjustment platform 8, which facilitates the positioning and tracking of the coordinates of the positioning ball 6 in the physical space coordinate system. At the same time, the telecentric camera 2 is controlled by the lifting platform 1 to clearly image the positioning ball 6, ensuring the accuracy of the coordinates of the center of the positioning ball 6 in the image coordinate system, thereby ensuring the accuracy of solving the mapping relationship and improving the accuracy of solving the reference axis.

[0071] Specifically, calculate the image coordinate system Img(x) img y imgRelative to the physical space coordinate system Stage(x) stage y stage The mapping process includes: Img(x) img y img ) and Stage(x stage y stage The following conditions must be met between the given conditions: (10) and (20)

[0072]

[0073] Wherein, calibration coefficient β is the linear magnification factor between the image coordinate system and the physical space coordinate system, calibration coefficient R is the relative rotation matrix between the image coordinate system and the physical space coordinate system, and calibration coefficient T is the relative offset matrix between the image coordinate system and the physical space coordinate system. Since there is relative magnification, rotation, and offset between the two coordinate systems, the calibration coefficients β, R, and T are obtained through formulas (10) and (20), which can realize the transformation from the image coordinate system to the physical space coordinate system, ensuring the accurate determination of the spatial position of the outer datum line of the lens under test.

[0074] Specifically, before determining 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 stage of the lens reference axis positioning platform, based on the shape of the lens under test, the process also includes: calibrating the relative horizontality of the support platform 4 of the lateral adjustment stage and the imaging plane of the telecentric camera 2. Pre-calibrating the support platform 4 and the telecentric camera 2 ensures that the reference axis is perpendicular to the imaging plane of the telecentric camera 2 after the lens under test is placed, reducing the tilt during lens placement. This allows for accurate detection of the lens's outline reference line and determination of the accurate position of the reference axis, improving the accuracy and consistency of reference axis positioning.

[0075] Specifically, there are four support platforms 4, designated as the first to fourth support platforms. The process of calibrating the horizontal adjustment platform's support platforms 4 relative to the imaging plane of the telecentric camera 2 includes: adjusting the positions of the four support platforms 4 according to the shape of the lens under test, ensuring all support platforms 4 are in contact with the support surface of the lens; adjusting the displacement adjustment platform 8 of the horizontal adjustment platform so that the first support platform is imaged at the center of the telecentric camera 2's field of view; adjusting the height of the lifting platform 1 of the lens reference axis positioning platform, and recording the height Z1 of the lifting platform 1 when the edge contour image of the first support platform is clearest; recording the heights Z2 to Z4 of the lifting platform 1 when the edge contour images of the second to fourth support platforms at the center of the telecentric camera 2's field of view are clearest; calculating the height differences Z1-Z2 and Z3-Z4; adjusting the pitch adjustment platform 7 of the horizontal adjustment platform, and repeatedly measuring and calculating the height difference Z. 1-Z2 and height difference Z3-Z4, until |Z1-Z2|≤10μm, |Z3-Z4|≤10μm. Utilizing the principle of image defocus curve, the position of the telecentric camera 2 can be finely adjusted by varying the sharpness of the edge contour of the support platform 4, ensuring the sharpest possible image and thus improving measurement accuracy. The first to fourth support platforms sequentially achieve clear imaging at the center of the telecentric camera 2's field of view, guaranteeing the accuracy and reliability of the height data Z1 to Z4 of the lifting platform 1. The height difference Z1 relative to the telecentric camera 2 at different positions on the lateral adjustment platform is calculated. 1- Z2 and Z3-Z4, the current height difference can directly indicate the different distance differences between the support platforms 4 and the plane of the telecentric camera 2. By adjusting the pitch adjustment platform 7, when |Z1-Z2|≤10μm and |Z3-Z4|≤10μm, it can be ensured that when the lens under test is placed between the support platforms 4, the outer baseline of the lens under test and the imaging plane of the telecentric camera 2 remain relatively horizontal.

[0076] Specifically, the process of determining the fitting position of the datum line of the lens under test in the physical space coordinate system according to the mapping relationship includes: fixing the bearing surface of the lens under test to the side of the bearing platform 4; obtaining the first and second datum lines of the lens under test; and calculating the first shape equation Fa in the physical space coordinate system corresponding to the first shape equation and the second shape equation Fb in the physical space coordinate system corresponding to the second shape equation, based on the mapping relationship. By transforming the two different first and second shape equations from the image coordinate system to the physical space coordinate system and determining their spatial positions (first shape equation Fa and second shape equation Fb), the spatial positioning of the lens under test is achieved, further ensuring high-precision datum axis positioning.

[0077] like Figure 3 As shown, the process of calculating the first shape equation Fa in the physical space coordinate system corresponding to the first shape datum A and the second shape equation Fb in the physical space coordinate system corresponding to the second shape datum B, based on the mapping relationship, includes: adjusting the displacement adjustment stage 8 and the lifting stage 1 to make the first shape datum A clearly imaged in the telecentric camera 2, and recording the coordinates (x, y) of the displacement adjustment stage 8. stage_a y stage_a ); Calculate the set of coordinates (x, y) of N points on the edge of the first shape reference A in the image coordinate system. img_a1 y img_a1 )~(x img_an y img_an ); Based on the calibration coefficients β, R, and T, the coordinate set (x) is calculated using formula (30). img_a1 y img_a1 )~(x img_an y img_an The set of coordinates (x) converted to the physical space coordinate systemstage_a1 y stage_a1 )~(x stage_an y stage_an ),

[0078]

[0079] According to the coordinate set (x stage_a1 y stage_a1 )~(x stage_an y stage_an ), and the first shape equation Fa is calculated by fitting.

[0080] The process of calculating the first shape equation Fa is to adjust the displacement adjustment stage 8 and the lifting stage 1 to ensure that the first shape reference A of the lens under test is clearly imaged in the telecentric camera 2. Then, the image coordinates of N points are obtained through edge detection, and the coordinates are transformed into the physical space coordinate system using the calibrated mapping relationship. Combined with the shape features of the first shape reference A, such as straight lines, curves, and feature points, the equation form of the first shape reference A is determined, and the actual spatial position of the first shape reference A in the physical space coordinate system is fitted.

[0081] like Figure 3 As shown, according to the mapping relationship, the process of calculating the first shape equation Fa in the physical space coordinate system corresponding to the first shape datum A and the second shape equation Fb in the physical space coordinate system corresponding to the second shape datum B also includes: adjusting the displacement adjustment stage 8 and the lifting stage 1 so that the second shape datum B is clearly imaged in the telecentric camera 2, and recording the coordinates (x, y) of the displacement adjustment stage 8. stage_b y stage_b ); Calculate the set of coordinates (x, y) of N points on the edge of the second shape reference B in the image coordinate system. img_b1 y img_b1 )~(x img_bn y img_bn ); Based on the calibration coefficients β, R, and T, the coordinate set (x) is calculated using formula (40). img_b1 y img_b1 )~(x img_bn y img_bn The set of coordinates (x) converted to the physical space coordinate system stage_b1 y stage_b1 )~(x stage_bn y stage_bn ),

[0082]

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

[0084] Similar to calculating the first shape equation Fa, the process of calculating the second shape equation Fb involves adjusting the displacement adjustment platform 8 and the lifting platform 1 to ensure that the second shape reference B of the lens under test is clearly imaged in the telecentric camera 2. Then, the image coordinates of N points are obtained through edge detection, and the coordinates are transformed into the physical space coordinate system using the calibrated mapping relationship. Combining the shape features of the second shape reference B, such as straight lines, curves, and feature points, the equation form of the second shape reference B is determined, and the actual spatial position of the second shape reference B in the physical space coordinate system is fitted.

[0085] Specifically, the process of obtaining the preset relationship between the reference axis and the outline reference line of the lens under test includes: obtaining the machining drawing of the lens under test; determining the distance La of the reference axis of the lens under test relative to the first outline reference A; and determining the distance Lb of the reference axis of the lens under test relative to the second outline reference B. By obtaining the relationship between the reference axis and the outline reference line specified in the design stage of the lens under test, the position of the reference axis that satisfies the preset relationship can be solved based on the obtained first outline equation Fa and second outline equation Fb. Of course, the machining drawing can be automatically read and the relevant parameters can be calculated by software, reducing the time for manual intervention and adjustment, and improving the efficiency of the entire positioning process.

[0086] Specifically, the process of determining the spatial position of the reference axis in the physical coordinate system based on the fitted position and preset relationship includes: determining the point coordinates (x... stage_cen y stage_cen ), such that it simultaneously satisfies the following conditions: the distance to the first shape equation Fa is La, and the distance to the second shape equation Fb is Lb, and the point coordinates (x... stage_cen y stage_cen () represents the position of the reference axis in the physical space coordinate system. For example... Figure 3 As shown, find the coordinates (x, y) of the point that satisfies the condition that the distance from the first shape equation Fa is La and the distance from the second shape equation Fb is Lb. stage_cen y stage_cen In other words, find the point where the reference axis passes through the plane of the coordinate system, and the straight line that is perpendicular to the plane of the coordinate system and passes through that point is the straight line where the reference axis is located, thus determining the position of the reference axis.

[0087] The lens reference axis positioning method of this application enables the spatial positioning of the optical lens reference axis on a positioning platform. It can be further integrated into a lens eccentricity detection system to provide an eccentricity reference, or into a lens assembly system to provide an assembly reference positioning. Furthermore, the above lens reference axis detection and positioning process, combined with software, achieves automated operation, significantly improving positioning efficiency. In addition, the current positioning method has low precision requirements for the positioning platform and can be adapted to different lenses, improving the versatility of both the positioning method and the positioning platform.

[0088] Obviously, the embodiments described above are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of this utility model.

[0089] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" 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., used in the specification, claims, and accompanying drawings of this 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 where appropriate so that the embodiments of this application described herein can be implemented in sequences other than those illustrated or described herein.

[0091] The above are merely preferred embodiments of this utility model and are not intended to limit the scope of this utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A lens reference axis positioning platform, characterized in that, include: A horizontal adjustment platform, comprising multiple adjustable support platforms (4), the support platforms (4) being used to fix the lens to be tested, the horizontal adjustment platform being able to move in the xy plane and adjust the pitch angle relative to the xy plane; A lifting platform (1) is spaced above the horizontal adjustment platform. The lifting platform (1) can move closer to or further away from the horizontal adjustment platform along the extension direction of the z-axis, and the z-axis is perpendicular to the xy plane. Telecentric camera (2), the telecentric camera (2) is fixed on the lifting platform (1), the telecentric camera (2) is used to detect the reference position of the shape of the lens to be tested; A 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 of claim 1, wherein, The lateral adjustment platform includes: The displacement adjustment stage (8) is capable of translation within the xy plane; A pitch adjustment platform (7) is fixed on the displacement adjustment platform (8). The pitch adjustment platform (7) can adjust the pitch angle relative to the xy plane. The lens to be tested is fixed on the pitch adjustment platform (7).

3. The lens reference axis positioning platform of claim 2, wherein, The pitch adjustment platform (7) has a lens fixture plane (5), and the support platform (4) and the positioning ball (6) are arranged on the lens fixture plane (5).

4. The lens reference axis positioning platform of claim 3, wherein, The lens reference axis positioning platform also includes a point light source (3) facing the transverse adjustment platform. The point light source (3) and the telecentric camera (2) form a coaxial optical path. The lens fixture plane (5) and the top surface of the support platform (4) can reflect the light emitted by the point light source (3).

5. The lens reference axis positioning platform of claim 4, wherein, The positioning ball (6) is located at the center of the lens fixture plane (5).

6. The lens reference axis positioning platform of claim 5, wherein, The lateral adjustment platform includes four support platforms (4), which surround the positioning ball (6) and are arranged opposite each other in pairs.

7. The lens reference axis positioning platform according to claim 2, characterized in that, The unidirectional positioning accuracy of the displacement adjustment stage (8) is less than or equal to 0.5 μm; and / or The repeatability of the displacement adjustment stage (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 step size of the lifting platform (1) is less than or equal to 2 μm; and / or The repeatability 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 support platform (4) and the top surface of the support platform (4) is within the range of 90±0.5°; and / or The straightness error of the side of the support platform (4) is less than or equal to 10 μm.

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