A method and device for detecting surface quality of general optical elements by rotating scanning

Abstract

This invention discloses a method and apparatus for rotating and scanning the surface quality of a general-purpose optical component. The scanning and scanning method includes: dividing the arc from the edge to the center of the component under test into n segments; concentric rotation imaging: the optical axis of the camera's imaging lens passes through the center of the optical sphere of the component under test, and the first segment begins with the camera's imaging lens aligned with the edge of the component under test. The component under test is rotated 360 degrees along its own optical axis, and the camera follows by scanning 360 degrees across the sphere, achieving an image of a ring-shaped band on the sphere; keeping the optical axis of the imaging lens always passing through the center of the optical sphere of the component under test, the angle between the imaging lens and the optical axis of the component under test is adjusted, and the second segment begins with the camera's imaging lens aligned with the edge of the component under test. The component under test is then rotated 360 degrees along its own optical axis, achieving an image of a ring-shaped band on the sphere, and so on, until the scanning and scanning of the surface of the component under test is completed. This invention is suitable for clear and blind-angle-free inspection of various surface-shaped optical components.

Description

Technical Field

[0001] This invention relates to a method and apparatus for rotating scanning detection of the surface quality of general-purpose optical components, belonging to the field of optical component surface quality detection technology. Background Technology

[0002] Due to their ease of manufacturing, the mainstream optical elements widely used in optical instruments are still composed of planar, spherical, and aspherical surfaces of revolution, as well as their arrangements and combinations.

[0003] Currently, while surface quality inspection of planar optical components still relies on human observation, this method is gradually being replaced by automated inspection equipment, such as in the inspection of mobile phone displays. However, the quality inspection of spherical and rotating aspherical optical surfaces still primarily depends on human observation. Although there is existing research on spherical surface defect detection, the accuracy and precision are very limited. For example, patent application number 202010916390.2 discloses a surface defect measurement device and method for spherical optical components. This method achieves in-situ surface defect detection by utilizing the difference in polarization characteristics between reflected light from a smooth surface and scattered light from surface defects, as well as the photoluminescence characteristics of contamination defects such as polishing fluid. However, this method has the following shortcomings: (a) the incident direction and angle of the illumination light are singular, and since surface defects have a certain directionality, some defects will inevitably go undetected; (b) it is difficult to adapt to the detection of concave spherical surfaces; (c) after swinging at a certain angle, the height of the spherical surface changes, causing the imaging lens to lose focus and the detection to fail.

[0004] With the mass production and use of mobile phone cameras, surveillance cameras, and vehicle cameras, a massive number of spherical and rotating aspherical optical surfaces are produced. However, the quality inspection of these optical surfaces relies heavily on a large workforce. Not only does this consume a huge amount of labor, but more importantly, production efficiency and quality stability have become bottlenecks for the industry. Summary of the Invention

[0005] This invention provides a method and apparatus for rotating scanning inspection of the surface quality of optical components, suitable for the inspection of various surface optical components such as spherical and rotating aspherical surfaces. It achieves clear scanning inspection of the optical component surface with no blind spots at 360°, improving the accuracy of inspection. It not only frees up a large amount of labor, but also ensures the stability of quality inspection and improves the production efficiency of the production line.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0007] A method for rotating and scanning the surface quality of a general-purpose optical element includes the following steps:

[0008] 1) Divide the arc of the component under test from the edge to the center into n segments;

[0009] 2) Concentric rotation shooting:

[0010] 21) The optical axis of the camera imaging lens passes through the center of the optical sphere of the device under test, and the camera imaging lens is aligned with the first segment from the edge of the device under test. The device under test is rotated 360 degrees along its own optical axis, and the camera will follow and scan 360 degrees across the sphere to achieve imaging of a ring-shaped band on the sphere.

[0011] 22) Keep the optical axis of the imaging lens always through the center of the optical sphere of the device under test, and adjust the angle between the imaging lens and the optical axis of the device under test so that the camera imaging lens is aligned with the second segment starting from the edge of the device under test. Rotate the device under test 360 degrees along its own optical axis to achieve imaging of a ring band on the sphere. Repeat this process until the scanning and detection of the surface of the device under test is completed.

[0012] Throughout the entire shooting process in step 2), the optical axis of the camera's imaging lens must always be kept through the center of the optical sphere of the element under test to ensure clear imaging from all angles.

[0013] Current imaging systems typically project information from the object plane onto a conjugate image plane via an optical system. This means that an imaging system can only provide a high-quality image of a flat object, and generally cannot provide a clear image of a curved object.

[0014] Due to the curvature of a sphere, it is generally impossible to achieve a clear image of a sphere using a single imaging method, meaning it is impossible to inspect the quality of a sphere using a single photograph.

[0015] For spherical or rotating aspherical surfaces, the spherical surface is subdivided, and a series of broken lines are used to replace the continuous spherical surface. The arc within the range of each broken line is replaced by a straight line. Considering that the imaging system has a certain depth of field, the principle of subdividing the arc and replacing the arc with broken lines is also practically feasible in engineering.

[0016] During the project implementation, it is required that the arc height cut by each segment of the broken line be less than or equal to the depth of field of the imaging lens.

[0017] The method of this application is universal and applicable to various surface types such as spheres and aspherical surfaces of revolution.

[0018] The camera and imaging lens used in this application can be directly adopted from existing commercially available products. The camera can be an area scan camera or a line scan camera.

[0019] A general-purpose rotating scanning device for detecting the surface quality of optical components includes a sample mounting device and a rotating shaft.

[0020] A longitudinal support structure is mounted on a rotating shaft, which can drive the longitudinal support structure to rotate. A linear moving shaft that can slide up and down is mounted on the longitudinal support structure. A crossbeam is mounted on the linear moving shaft, and a camera and an imaging lens are mounted on the crossbeam. Rotating the rotating shaft can drive the camera and imaging lens to rotate around the extension line of the axis of the rotating shaft, and during the rotation, the optical axis of the camera and the imaging lens always intersects with the extension line of the axis of the rotating shaft.

[0021] The sample mounting device is equipped with a sample clamp with adjustable height. The sample clamp is equipped with an XY fine-tuning mechanism and a rotation mechanism. The rotation mechanism can rotate along the second rotation axis, which intersects perpendicularly with the extension line of the first rotation axis.

[0022] The sample mounting device can realize various structures of this application.

[0023] As one specific implementation scheme, a device for rotating scanning detection of the surface quality of a general optical element includes a first rotating shaft and a third rotating shaft, which are opposite to each other and coaxially arranged.

[0024] A longitudinal support structure is mounted on a rotating shaft, which can drive the longitudinal support structure to rotate. A linear moving shaft that can slide up and down is mounted on the longitudinal support structure. A crossbeam is mounted on the linear moving shaft, and a camera and an imaging lens are mounted on the crossbeam. Rotating the rotating shaft can drive the camera and imaging lens to rotate around the extension line of the axis of the rotating shaft, and during the rotation, the optical axis of the camera and the imaging lens always intersects with the extension line of the axis of the rotating shaft.

[0025] A longitudinal support structure is installed on the rotating shaft three, which can drive the longitudinal support structure two to rotate. A linear moving shaft two that can slide up and down is installed on the longitudinal support structure two. A crossbeam two is installed on the linear moving shaft two. A sample fixture is provided on the crossbeam two. The sample fixture is provided with an XY fine adjustment mechanism and a rotation mechanism. The rotation mechanism can rotate around the rotating shaft two. The extension lines of the axes of the rotating shaft two and the rotating shaft three are perpendicular to each other. The rotating shaft two overlaps with the optical axis of the device under test.

[0026] The aforementioned sample fixture is mainly used for clamping and positioning the component under test, so that the imaging system on the right can take pictures; while the right side of the structure is mainly used to clamp the camera and adjust the camera's angle and orientation to achieve scanning and imaging detection of the entire spherical surface under test.

[0027] The sample fixture described above is equipped with an XY fine-tuning mechanism and a rotation mechanism, which means that the sample fixture has the function of adjusting in the X and Y directions and the function of rotating the sample (the element to be tested).

[0028] The sample holder is also equipped with a leveling mechanism to prevent the sample from tilting.

[0029] The aforementioned XY fine-tuning mechanism is used to adjust the position of the component under test (DUT) in the X and Y directions so that the optical axis of the DUT is vertically upward and coaxial with the camera and imaging lens; the rotation mechanism is used to drive the DUT to rotate; and the horizontal adjustment mechanism is used to adjust the horizontality of the DUT. The XY fine-tuning mechanism, rotation mechanism, and horizontal adjustment mechanism in this application can all directly adopt existing structures. This application does not make any special improvements to the aforementioned components themselves, and therefore will not be described in detail.

[0030] The scanning detection method using the aforementioned general-purpose optical element surface quality rotation scanning detection device includes the following steps:

[0031] 1) Rotate the third rotation axis to adjust the second longitudinal support structure and the second linear movement axis to a vertical state, clamp the component under test onto the sample fixture, with the optical spherical surface of the component under test facing upwards; rotate the first rotation axis to adjust the first longitudinal support structure and the first linear movement axis to a vertical state, with the camera and imaging lens facing vertically downwards;

[0032] 2) Fine-tune the XY fine-tuning mechanism on the sample fixture so that the optical axis of the component under test is vertically upward and coaxial with the camera and imaging lens;

[0033] 3) Adjust the position of the second linear movement axis so that the center of the optical sphere of the component under test falls on the extension line of the first rotation axis. The first and third rotation axes are set coaxially, that is, the extension line of the first rotation axis is collinear with the extension line of the third rotation axis.

[0034] 4) Divide the arc from the edge to the center of the component under test into n segments; rotate the first rotating axis, and the first supporting structure rotates around the first rotating axis to adjust the angle between the imaging lens and the second rotating axis, so that the imaging lens is aligned with the first segment from the edge of the component under test, and the optical axis of the imaging lens always passes through the center of the optical sphere. Driven by the rotating mechanism, the component under test rotates 360 degrees around the second rotating axis, and the camera will follow and scan 360 degrees across the sphere to achieve imaging of a ring-shaped band on the sphere.

[0035] 5) Keep the optical axis of the imaging lens always through the center of the optical sphere of the device under test, and adjust the angle between the imaging lens and the optical axis of the device under test so that the camera imaging lens is aligned with the second segment starting from the edge of the device under test. Rotate the device under test 360 degrees along its own optical axis to achieve imaging of a ring-shaped band of the sphere. Repeat this process until imaging of each segment is completed, which means that the scanning and detection of the entire optical sphere of the device under test is completed.

[0036] In step 1) above, the initial height of the sample fixture is located near the height of the three axes of rotation (this position is also the loading and unloading position of the sample). If the optical spherical surface of the component under test is a concave spherical surface, the second linear movement axis is adjusted downwards to approximately the height of the radius of curvature. If the optical spherical surface of the component under test is a convex spherical surface, the second linear movement axis is adjusted upwards to approximately the height of the radius of curvature.

[0037] To further improve image clarity, step 3) includes the following steps:

[0038] 31) Rotate the longitudinal support structure around the rotation axis to adjust the angle between the imaging lens and the rotation axis, so that the imaging lens is aligned with the edge of the optical spherical surface of the device under test; then, adjust the distance between the imaging lens and the device under test by moving the linear movement axis up and down to obtain a clear image of the edge of the device under test.

[0039] 32) Rotate the sample to be tested 360 degrees along the second rotation axis. By observing the clarity of the edge image of the sample to be tested and the position drift on the image, adjust the level of the sample to be tested through the level adjustment mechanism until the clarity of the edge of the sample to be tested does not change with the rotation of the sample, and the position of the edge of the sample to be tested on the image does not drift with the rotation of the sample. At this time, the level of the sample to be tested is guaranteed.

[0040] 33) Turn on the coaxial illumination source in the imaging lens to illuminate the optical spherical surface of the device under test (DUT). Then, adjust the distance between the imaging lens and the DUT by moving the linear axis one up and down until the light reflected from the DUT's optical spherical surface is imaged onto the camera's image plane. Next, adjust the angle between the imaging lens and the rotation axis two to allow the coaxial illumination light to sweep across the DUT's optical spherical surface. Observe the size and shape of the reflected light on the image plane. If the size and shape of the reflected light on the image plane change with the angle between the imaging lens and the rotation axis two, the height of the sample clamp needs to be adjusted up or down until the reflected light on the image plane is imaged correctly when the angle between the imaging lens and the rotation axis two is adjusted. The size and shape on the plane no longer change. At this point, the center of the optical sphere being measured falls on the extension of the first rotation axis. This is the concentricity adjustment. That is, if the center of the convex sphere being measured falls exactly on the first rotation axis, it means that the convex sphere and the first rotation axis are concentric. Then, no matter how the imaging lens swings, as long as the optical axis of the lens always points to the rotation axis, the degree of focus of the lens on any position of the convex sphere is the same. Conversely, if the convex sphere and the first rotation axis are not concentric, when the imaging lens swings to different angles, especially when it is aligned with the edge of the sample being measured, its degree of focus will change. At this time, the coaxiality and levelness of the sample need to be further adjusted until the same degree of focus is achieved.

[0041] 34) Fine-tune the XY fine-tuning mechanism on the sample fixture so that the optical axis of the component under test is vertically upward, and repeat step 32) so that the imaging lens can achieve clear imaging of the spherical edge of the component under test. At this point, the conditions for scanning and detecting the optical spherical surface are met.

[0042] The imaging lens is designed to house an illumination source that can provide illumination that is completely coaxial with the imaging lens. This is a relatively mature existing technology and will not be elaborated further.

[0043] In step 4) above, the arc from the edge to the center of the component under test is divided into n broken line segments with an arc height ≤ the depth of field of the imaging lens. That is, the step distance of the angle between the imaging lens and the second rotation axis is calculated based on the radius of curvature of the spherical surface under test and the depth of field parameters of the lens.

[0044] As another specific implementation structure: a device for rotating scanning detection of the surface quality of general-purpose optical elements, including a lifting platform and a rotating shaft;

[0045] A longitudinal support structure is mounted on a rotating shaft, which can drive the longitudinal support structure to rotate. A linear moving shaft that can slide up and down is mounted on the longitudinal support structure. A crossbeam is mounted on the linear moving shaft, and a camera and an imaging lens are mounted on the crossbeam. Rotating the rotating shaft can drive the camera and imaging lens to rotate around the extension line of the axis of the rotating shaft, and during the rotation, the optical axis of the camera and the imaging lens always intersects with the extension line of the axis of the rotating shaft.

[0046] The lifting platform is equipped with a sample clamp, which has an XY fine-tuning mechanism and a rotation mechanism. The rotation mechanism can rotate along the second rotation axis, which intersects perpendicularly with the extension line of the first rotation axis.

[0047] The lifting platform can be raised and lowered, thereby moving the sample clamps up and down. The specific structure of the lifting platform can adopt an existing mature structure.

[0048] The sample holder described above is equipped with a leveling mechanism to prevent the sample from tilting.

[0049] In both structures of this application, rotation axis one and rotation axis two must be on the same plane and intersect at a point.

[0050] The left side of the aforementioned structure is mainly used for clamping and positioning the sample to be tested, so that the imaging system on the right can take pictures; while the right side of the structure is mainly used to clamp the camera and adjust the camera's angle and orientation to achieve scanning and imaging detection of the entire spherical surface being tested.

[0051] The scanning detection method using the aforementioned general-purpose optical element surface quality rotation scanning detection device includes the following steps:

[0052] 1) Clamp the component under test onto the sample holder with the optical spherical surface of the component under test facing upward; rotate the first rotation axis to adjust the first longitudinal support structure and the first linear movement axis to a vertical state, with the camera and imaging lens facing vertically downward;

[0053] 2) Fine-tune the XY fine-tuning mechanism on the sample fixture so that the optical axis of the component under test is vertically upward and coaxial with the camera and imaging lens;

[0054] 3) Adjust the height of the lifting platform so that the center of the optical sphere of the component under test falls on the extension line of the first axis of rotation. The first and third axes of rotation are coaxial, that is, the extension line of the first axis of rotation is collinear with the extension line of the third axis of rotation.

[0055] 4) Divide the arc from the edge to the center of the component under test into n segments; rotate the first rotating axis, and the first supporting structure rotates around the first rotating axis to adjust the angle between the imaging lens and the second rotating axis, so that the imaging lens is aligned with the first segment from the edge of the component under test, and the optical axis of the imaging lens always passes through the center of the optical sphere. Driven by the rotating mechanism, the component under test rotates 360 degrees around the second rotating axis, and the camera will follow and scan 360 degrees across the sphere to achieve imaging of a ring-shaped band on the sphere.

[0056] 5) Keep the optical axis of the imaging lens always through the center of the optical sphere of the device under test, and adjust the angle between the imaging lens and the optical axis of the device under test so that the camera imaging lens is aligned with the second segment starting from the edge of the device under test. Rotate the device under test 360 degrees along its own optical axis to achieve imaging of a ring-shaped band of the sphere. Repeat this process until imaging of each segment is completed, which means that the scanning and detection of the entire optical sphere of the device under test is completed.

[0057] In step 1) above, the initial height of the sample fixture is located near the height of the axis of rotation (this position is also the loading and unloading position of the sample). If the optical spherical surface of the component under test is a concave spherical surface, the height of the lifting platform is reduced by approximately the height of the radius of curvature. If the optical spherical surface of the component under test is a convex spherical surface, the height of the lifting platform is increased by approximately the height of the radius of curvature.

[0058] To further improve image clarity, step 3) includes the following steps:

[0059] 31) Rotate the longitudinal support structure around the rotation axis to adjust the angle between the imaging lens and the rotation axis, so that the imaging lens is aligned with the edge of the optical spherical surface of the device under test; then, adjust the distance between the imaging lens and the device under test by moving the linear movement axis up and down to obtain a clear image of the edge of the device under test.

[0060] 32) Rotate the sample to be tested 360 degrees along the second rotation axis. By observing the clarity of the edge image of the sample to be tested and the position drift on the image, adjust the level of the sample to be tested through the level adjustment mechanism until the clarity of the edge of the sample to be tested does not change with the rotation of the sample, and the position of the edge of the sample to be tested on the image does not drift with the rotation of the sample. At this time, the level of the sample to be tested is guaranteed.

[0061] 33) Turn on the coaxial illumination source in the imaging lens to illuminate the optical spherical surface of the device under test (DUT). Then, adjust the distance between the imaging lens and the DUT by moving the linear axis one up and down until the light reflected from the DUT's optical spherical surface is imaged onto the camera's image plane. Next, adjust the angle between the imaging lens and the rotation axis two to allow the coaxial illumination light to sweep across the DUT's optical spherical surface. Observe the size and shape of the reflected light on the image plane. If the size and shape of the reflected light on the image plane change with the angle between the imaging lens and the rotation axis two, the height of the sample clamp needs to be adjusted up or down until the reflected light on the image plane is imaged correctly when the angle between the imaging lens and the rotation axis two is adjusted. The size and shape on the plane no longer change. At this point, the center of the optical sphere being measured falls on the extension of the first rotation axis. This is the concentricity adjustment. That is, if the center of the convex sphere being measured falls exactly on the first rotation axis, it means that the convex sphere and the first rotation axis are concentric. Then, no matter how the imaging lens swings, as long as the optical axis of the lens always points to the rotation axis, the degree of focus of the lens on any position of the convex sphere is the same. Conversely, if the convex sphere and the first rotation axis are not concentric, when the imaging lens swings to different angles, especially when it is aligned with the edge of the sample being measured, its degree of focus will change. At this time, the coaxiality and levelness of the sample need to be further adjusted until the same degree of focus is achieved.

[0062] 34) Fine-tune the XY fine-tuning mechanism on the sample fixture so that the optical axis of the component under test is vertically upward, and repeat step 32) so that the imaging lens can achieve clear imaging of the spherical edge of the component under test. At this point, the conditions for scanning and detecting the optical spherical surface are met.

[0063] In step 4) above, the arc from the edge to the center of the component under test is divided into n broken line segments with an arc height ≤ the depth of field of the imaging lens. That is, the step distance of the angle between the imaging lens and the second rotation axis is calculated based on the radius of curvature of the spherical surface under test and the depth of field parameters of the lens.

[0064] Any techniques not mentioned in this invention are based on existing technologies.

[0065] This invention relates to a method and apparatus for rotating scanning and detecting the surface quality of general-purpose optical components. It is suitable for detecting various surface types of optical components, such as spherical and rotating aspherical surfaces. It achieves clear scanning and detection of the optical component surface with no blind spots at 360°, improving the accuracy of detection. It not only frees up a large amount of labor but also ensures the stability of quality detection and improves the production efficiency of the production line. Attached Figure Description

[0066] Figure 1 This is a schematic diagram illustrating the principle of surface planarization and subdivision of the optical element in this invention.

[0067] Figure 2 This is a schematic diagram illustrating the principle of concentric rotational imaging in this invention.

[0068] Figure 3 This is the structure of the device for rotating scanning detection of the surface quality of general-purpose optical elements according to the present invention;

[0069] Figure 4 This is a schematic diagram illustrating the concentricity adjustment of a convex spherical surface.

[0070] Figure 5 This is a schematic diagram illustrating the concentricity adjustment of a concave spherical surface.

[0071] Figure 6 This is structure two of the device for rotating scanning detection of the surface quality of general-purpose optical elements according to the present invention;

[0072] In the figure, 1 is the second rotation axis, 2 is the camera, 3 is the imaging lens, 4 is the center of the sphere of the component under test, 5 is the first rotation axis, 51 is the first longitudinal support structure, 52 is the first linear movement axis, 53 is the first crossbeam, 6 is the third rotation axis, 61 is the second longitudinal support structure, 62 is the second linear movement axis, 63 is the second crossbeam, 7 is the sample fixture, and 8 is the lifting platform. Detailed Implementation

[0073] To better understand the present invention, the following embodiments further illustrate the content of the present invention, but the content of the present invention is not limited to the following embodiments.

[0074] The directional terms used in this application, such as up and down, left and right, horizontal, and vertical, are all based on the relative orientations or positional relationships shown in the attached drawings and should not be construed as absolute limitations on this application.

[0075] Example 1

[0076] A method for rotating and scanning to detect the surface quality of a spherical optical element includes the following steps:

[0077] 1) Divide the arc of the component under test from the edge to the center into n segments, and the arc height of each segment is less than or equal to the depth of field of the imaging lens. It should be noted that this subdivision method is also suitable for rotating aspherical surfaces. The deviation of the rotating aspherical surface from the spherical surface is generally not large. Even if the deviation is relatively large, the problem can be solved by increasing the subdivision angle. Therefore, without loss of generality, this example uses spherical surface detection to illustrate the surface detection method.

[0078] Current imaging systems typically project information from the object plane onto a conjugate image plane via an optical system. This means that an imaging system can only provide a high-quality image of a flat object, and generally cannot provide a clear image of a curved object.

[0079] Due to the curvature of a sphere, it is generally impossible to achieve a clear image of a sphere using a single imaging method, meaning it is impossible to inspect the quality of a sphere using a single photograph.

[0080] For spherical or aspherical surfaces of rotation, the spherical surface can be subdivided, such as... Figure 1 As shown, a series of broken lines are used to replace a continuous sphere, and the arc within each broken line is replaced by a straight line. Considering that the imaging system has a certain depth of field, the principle of subdividing the arc and replacing it with broken lines is also practically feasible in engineering. In engineering implementation, it is required that the arc height cut by each broken line segment should be less than or equal to the camera's depth of field.

[0081] 2) Concentric rotation shooting:

[0082] 21) For example Figure 2 As shown, the optical element is typically a portion of the symmetrical sphere intercepted by the axis of rotational symmetry of a perpendicular sphere (the dashed line in the figure). The optical axis of the camera's imaging lens passes through the center of the optical sphere of the element under test. The first segment of the camera's imaging lens is aligned with the edge of the element under test. The element under test is rotated 360 degrees along its own optical axis, and the camera will follow and scan 360 degrees across the sphere to achieve imaging of a ring-shaped band on the sphere. The camera can be an area scan camera or a line scan camera.

[0083] 22) Keep the optical axis of the imaging lens always through the center of the optical sphere of the device under test (DUT), and adjust the angle between the imaging lens and the optical axis of the DUT so that the camera's imaging lens is aligned with the second segment starting from the edge of the DUT. Rotate the DUT 360 degrees along its own optical axis to achieve imaging of a ring-shaped band on the sphere. Repeat this process until the scanning and detection of the DUT surface is complete. Figure 2The dotted line represents a spherical lens. The arc from the edge to the center is subdivided into two segments. By scanning twice in this way, the entire spherical lens can be imaged and scanned. It is important to note that throughout the entire imaging process in step 2), the optical axis of the camera's imaging lens must always be kept through the center of the optical sphere of the element under test.

[0084] Example 2

[0085] like Figure 3 As shown, a general-purpose optical element surface quality rotation scanning detection device includes a first rotation axis and a third rotation axis, which are opposite to each other and coaxially arranged.

[0086] A longitudinal support structure is mounted on a rotating shaft, which can drive the longitudinal support structure to rotate. A linear moving shaft that can slide up and down is mounted on the longitudinal support structure. A crossbeam is mounted on the linear moving shaft, and a camera and an imaging lens are mounted on the crossbeam. Rotating the rotating shaft can drive the camera and imaging lens to rotate around the extension line of the axis of the rotating shaft, and during the rotation, the optical axis of the camera and the imaging lens always intersects with the extension line of the axis of the rotating shaft.

[0087] A longitudinal support structure is installed on the rotating shaft three, which can drive the longitudinal support structure two to rotate. A linear moving shaft two that can slide up and down is installed on the longitudinal support structure two. A crossbeam two is installed on the linear moving shaft two. A horizontal adjustment mechanism is provided on the crossbeam two. An XY fine adjustment mechanism is provided on the horizontal adjustment mechanism. A rotating mechanism is provided on the XY fine adjustment mechanism. A sample clamp is provided on the rotating mechanism. The rotating mechanism can rotate around the rotating shaft two. The rotating shaft two intersects perpendicularly with the extension lines of the axes of the rotating shaft one and the rotating shaft three. The rotating shaft two overlaps with the optical axis of the component under test.

[0088] The method for scanning and inspecting optical elements using the aforementioned general-purpose optical element surface quality rotation scanning inspection apparatus includes the following steps:

[0089] 1) Rotate the third rotating axis to adjust the second longitudinal support structure and the second linear moving axis to a vertical position. By sliding the second linear moving axis up and down, the height of the sample fixture is located near the height of the axis of the third rotating axis (this position is the loading and unloading position of the sample). Clamp the component under test onto the sample fixture with the optical spherical surface of the component under test facing upward (the optical spherical surface mentioned below); rotate the first rotating axis to adjust the first longitudinal support structure and the first linear moving axis to a vertical position with the camera and imaging lens facing vertically downward.

[0090] 2) In this example, the optical spherical surface of the component under test (convex lens) is a convex spherical surface. The linear movement axis is adjusted upwards to approximately the height of the radius of curvature. Figure 3(the dotted part in the image), and then fine-tune the XY fine-tuning mechanism on the sample fixture so that the optical axis of the component under test is vertically upward and coaxial with the camera and imaging lens;

[0091] 3) Rotate the longitudinal support structure around the first rotation axis to adjust the angle between the imaging lens and the second rotation axis, so that the imaging lens is aligned with the edge of the optical spherical surface of the device under test; then, adjust the distance between the imaging lens and the device under test by moving the linear movement axis one up and down to obtain a clear image of the edge of the device under test.

[0092] 4) Rotate the sample to be tested 360 degrees along the second rotation axis. By observing the clarity of the edge image of the sample to be tested and the position drift on the image, adjust the level of the sample to be tested through the level adjustment mechanism until the clarity of the edge of the sample to be tested does not change with the rotation of the sample, and the position of the edge of the sample to be tested on the image does not drift with the rotation of the sample. At this time, the level of the sample to be tested is guaranteed.

[0093] 5) Turn on the coaxial illumination source in the imaging lens to illuminate the optical spherical surface of the device under test (DUT). Then, adjust the distance between the imaging lens and the DUT by moving the linear axis up and down until the light reflected back from the DUT's optical spherical surface is imaged onto the camera's image plane; then, as... Figure 4 As shown, adjust the angle between the imaging lens and the second rotation axis to allow the coaxial illumination light to sweep across the optical spherical surface of the component under test. Observe the size and shape of the reflected light on the image plane. If the size and shape of the reflected light on the image plane change with the angle between the imaging lens and the second rotation axis, the height of the sample fixture needs to be adjusted up or down until the size and shape of the reflected light on the image plane no longer change when the angle between the imaging lens and the second rotation axis is adjusted. At this point, the center of the optical spherical surface under test falls on the extension line of the first rotation axis. This is the concentricity adjustment. In other words, if the center of the convex spherical surface being measured falls exactly on the first rotation axis, it indicates that the convex spherical surface and the first rotation axis are concentric. Then, no matter how the imaging lens swings, as long as the optical axis of the lens always points to the rotation axis, the degree of focus of the lens on any position of the convex spherical surface will be the same. Conversely, if the convex spherical surface and the first rotation axis are not concentric, when the imaging lens swings to different angles, especially when it is aimed at the edge of the sample to be measured, its degree of focus will change. At this time, the coaxiality and levelness of the sample need to be further adjusted until the same degree of focus is achieved.

[0094] 6) Fine-tune the XY fine-tuning mechanism on the sample fixture so that the optical axis of the component under test is vertically upward, and repeat step 4) so ​​that the imaging lens can achieve clear imaging of the spherical edge of the component under test. At this point, the conditions for scanning and detecting the optical spherical surface are met.

[0095] 7) Divide the arc from the edge to the center of the component under test into n segments, and the arc height of each segment is less than or equal to the depth of field of the imaging lens; rotate the first rotation axis, and the first support structure rotates around the first rotation axis to adjust the angle between the imaging lens and the second rotation axis, so that the imaging lens is aligned with the first segment from the edge of the component under test, and the optical axis of the imaging lens always passes through the center of the optical sphere. Driven by the rotation mechanism, the component under test rotates 360 degrees around the second rotation axis, and the camera will follow and scan 360 degrees across the sphere to achieve imaging of a ring band on the sphere.

[0096] 8) Keep the optical axis of the imaging lens always through the center of the optical sphere of the device under test (DUT), and adjust the angle between the imaging lens and the optical axis of the DUT so that the camera's imaging lens is aligned with the second segment starting from the edge of the DUT. Rotate the DUT 360 degrees along its own optical axis to achieve imaging of a ring-shaped band on the sphere. Repeat this process until each segment is imaged, which means the scanning and detection of the entire optical sphere of the DUT is completed. The detection accuracy reaches below 0.5µm; within an error range of 2.5µm, the accuracy rate is above 99.98%; within an error range of 3µm, the accuracy rate is above 99.9997%.

[0097] Example 3

[0098] Unlike Example 2, the optical surface of the element under test (concave lens) is a concave spherical surface. In step 2), the linear movement axis 2 is adjusted downwards by approximately the height of the radius of curvature. Figure 3 (The solid line portion in the figure), the rest are the same as in Example 2. The schematic diagram of the concentricity adjustment of the concave spherical surface in step 5) is shown below. Figure 5 As shown.

[0099] Example 4

[0100] like Figure 6 As shown, a general-purpose optical element surface quality rotary scanning detection device includes a lifting platform and a rotating shaft.

[0101] A longitudinal support structure is mounted on a rotating shaft, which can drive the longitudinal support structure to rotate. A linear moving shaft that can slide up and down is mounted on the longitudinal support structure. A crossbeam is mounted on the linear moving shaft, and a camera and an imaging lens are mounted on the crossbeam. Rotating the rotating shaft can drive the camera and imaging lens to rotate around the extension line of the axis of the rotating shaft, and during the rotation, the optical axis of the camera and the imaging lens always intersects with the extension line of the axis of the rotating shaft.

[0102] The lifting platform is equipped with a horizontal adjustment mechanism, which in turn is equipped with an XY fine-tuning mechanism. The XY fine-tuning mechanism is equipped with a rotating mechanism, which is equipped with a sample clamp. The rotating mechanism can rotate along the second rotating axis, which intersects perpendicularly with the extension line of the first rotating axis.

[0103] The method for scanning and inspecting optical elements using the aforementioned general-purpose optical element surface quality rotation scanning inspection apparatus includes the following steps:

[0104] 1) Adjust the height of the lifting platform so that the height of the sample fixture is near the height of the three axes of the rotation axis (this position is the loading and unloading position of the sample). Clamp the component to be tested onto the sample fixture with the optical spherical surface of the component to be tested facing upward (the optical spherical surface mentioned below); rotate the first rotation axis to adjust the first longitudinal support structure and the first linear movement axis to a vertical state, with the camera and imaging lens facing vertically downward.

[0105] 2) In this example, the optical spherical surface of the component under test is a convex spherical surface. Lowering the height of the lifting platform is approximately equal to the height of the radius of curvature. Figure 3 (the dotted part in the image), and then fine-tune the XY fine-tuning mechanism on the sample fixture so that the optical axis of the component under test is vertically upward and coaxial with the camera and imaging lens;

[0106] 3) Rotate the longitudinal support structure around the first rotation axis to adjust the angle between the imaging lens and the second rotation axis, so that the imaging lens is aligned with the edge of the optical spherical surface of the device under test; then, adjust the distance between the imaging lens and the device under test by moving the linear movement axis one up and down to obtain a clear image of the edge of the device under test.

[0107] 4) Rotate the sample to be tested 360 degrees along the second rotation axis. By observing the clarity of the edge image of the sample to be tested and the position drift on the image, adjust the level of the sample to be tested through the level adjustment mechanism until the clarity of the edge of the sample to be tested does not change with the rotation of the sample, and the position of the edge of the sample to be tested on the image does not drift with the rotation of the sample. At this time, the level of the sample to be tested is guaranteed.

[0108] 5) Turn on the coaxial illumination source in the imaging lens to illuminate the optical spherical surface of the device under test (DUT). Then, adjust the distance between the imaging lens and the DUT by moving the linear axis up and down until the light reflected back from the DUT's optical spherical surface is imaged onto the camera's image plane; then, as... Figure 4As shown, adjust the angle between the imaging lens and the second rotation axis to allow the coaxial illumination light to sweep across the optical spherical surface of the component under test. Observe the size and shape of the reflected light on the image plane. If the size and shape of the reflected light on the image plane change with the angle between the imaging lens and the second rotation axis, the height of the sample fixture needs to be adjusted up or down until the size and shape of the reflected light on the image plane no longer change when the angle between the imaging lens and the second rotation axis is adjusted. At this point, the center of the optical spherical surface under test falls on the extension line of the first rotation axis. This is the concentricity adjustment. In other words, if the center of the convex spherical surface being measured falls exactly on the first rotation axis, it indicates that the convex spherical surface and the first rotation axis are concentric. Then, no matter how the imaging lens swings, as long as the optical axis of the lens always points to the rotation axis, the degree of focus of the lens on any position of the convex spherical surface will be the same. Conversely, if the convex spherical surface and the first rotation axis are not concentric, when the imaging lens swings to different angles, especially when it is aimed at the edge of the sample to be measured, its degree of focus will change. At this time, the coaxiality and levelness of the sample need to be further adjusted until the same degree of focus is achieved.

[0109] 6) Fine-tune the XY fine-tuning mechanism on the sample fixture so that the optical axis of the component under test is vertically upward, and repeat step 4) so ​​that the imaging lens can achieve clear imaging of the spherical edge of the component under test. At this point, the conditions for scanning and detecting the optical spherical surface are met.

[0110] 7) Divide the arc from the edge to the center of the component under test into n segments, and the arc height of each segment is less than or equal to the depth of field of the imaging lens; rotate the first rotation axis, and the first support structure rotates around the first rotation axis to adjust the angle between the imaging lens and the second rotation axis, so that the imaging lens is aligned with the first segment from the edge of the component under test, and the optical axis of the imaging lens always passes through the center of the optical sphere. Driven by the rotation mechanism, the component under test rotates 360 degrees around the second rotation axis, and the camera will follow and scan 360 degrees across the sphere to achieve imaging of a ring band on the sphere.

[0111] 8) Keep the optical axis of the imaging lens always through the center of the optical sphere of the device under test (DUT), and adjust the angle between the imaging lens and the optical axis of the DUT so that the camera's imaging lens is aligned with the second segment starting from the edge of the DUT. Rotate the DUT 360 degrees along its own optical axis to achieve imaging of a ring-shaped band on the sphere. Repeat this process until each segment is imaged, which means the scanning and detection of the entire optical sphere of the DUT is completed. The detection accuracy reaches below 0.5µm; within an error range of 2.5µm, the accuracy rate is above 99.98%; within an error range of 3µm, the accuracy rate is above 99.9997%.

[0112] If the optical spherical surface of the component under test is a concave spherical surface, in step 2), the lifting platform is adjusted downwards by approximately the radius of curvature, and the rest are handled in accordance with the above process.

Claims

1. A method for rotating and scanning to detect the surface quality of a general-purpose optical element, characterized in that: The device used for rotating scanning detection of the surface quality of general-purpose optical components includes a first rotating axis and a third rotating axis, which are opposite to each other and coaxially arranged. A longitudinal support structure is mounted on a rotating shaft, which can drive the longitudinal support structure to rotate. A linear moving shaft that can slide up and down is mounted on the longitudinal support structure. A crossbeam is mounted on the linear moving shaft, and a camera and an imaging lens are mounted on the crossbeam. Rotating the rotating shaft can drive the camera and imaging lens to rotate around the extension line of the axis of the rotating shaft, and during the rotation, the optical axis of the camera and the imaging lens always intersects with the extension line of the axis of the rotating shaft. A longitudinal support structure 2 is installed on the rotating shaft 3, and the rotating shaft 3 can drive the longitudinal support structure 2 to rotate; a linear moving shaft 2 that can slide up and down is installed on the longitudinal support structure 2, and a crossbeam 2 is installed on the linear moving shaft 2. A sample clamp is provided on the crossbeam 2, and the sample clamp is provided with an XY fine adjustment mechanism and a rotation mechanism. The rotation mechanism can rotate around the rotating shaft 2, and the extension lines of the axes of the rotating shaft 2 and the rotating shaft 3 are perpendicular to each other. A method for rotating and scanning the surface quality of general-purpose optical components includes the following steps: 1) Rotate the rotating shaft three to adjust the longitudinal support structure two and the linear moving shaft two to a vertical state, clamp the component under test onto the sample fixture, with the optical spherical surface of the component under test facing upwards; Rotate the first rotation axis to adjust the first longitudinal support structure and the first linear movement axis to a vertical position, so that the camera and imaging lens are vertically downward. 2) Fine-tune the XY fine-tuning mechanism on the sample fixture so that the optical axis of the component under test is vertically upward and coaxial with the camera and imaging lens; 3) Adjust the position of the second linear movement axis so that the center of the optical sphere of the component under test falls on the extension line of the first rotation axis; 4) Divide the arc of the component under test from the edge to the center into n segments; Rotate the first rotating shaft, and the first supporting structure rotates around the first rotating shaft to adjust the angle between the imaging lens and the second rotating shaft, so that the imaging lens is aligned with the first segment starting from the edge of the component under test, and the optical axis of the imaging lens always passes through the center of the optical sphere. Driven by the rotating mechanism, the component under test rotates 360 degrees around the second rotating shaft, and the camera will follow and scan 360 degrees across the sphere to achieve imaging of a ring-shaped band on the sphere. 5) Keep the optical axis of the imaging lens through the center of the optical sphere of the device under test, and adjust the angle between the imaging lens and the optical axis of the device under test so that the camera imaging lens is aligned with the second segment starting from the edge of the device under test. Rotate the device under test 360 degrees along its own optical axis to achieve imaging of a ring-shaped band of the sphere. Repeat this process until imaging of each segment is completed, which means that the scanning and detection of the entire optical sphere of the device under test is completed. In step 1), the height of the sample fixture is located near the height of the three axes of rotation. If the optical spherical surface of the component under test is a concave spherical surface, the height of the radius of curvature of the second linear movement axis is adjusted downward. If the optical spherical surface of the component under test is a convex spherical surface, the height of the radius of curvature of the second linear movement axis is adjusted upward. Step 3) includes the following steps: 31) Rotate the longitudinal support structure one around the rotation axis one to adjust the angle between the imaging lens and the rotation axis two, so that the imaging lens is aligned with the edge of the optical spherical surface of the device under test; then, adjust the distance between the imaging lens and the device under test by moving the linear movement axis one up and down to obtain a clear image of the edge of the device under test. 32) Rotate the sample to be tested 360 degrees along the second rotation axis. By observing the clarity of the edge image of the sample to be tested and the position drift on the image, adjust the level of the sample to be tested through the level adjustment mechanism until the clarity of the edge of the sample to be tested does not change with the rotation of the sample, and the position of the edge of the sample to be tested on the image does not drift with the rotation of the sample. At this time, the level of the sample to be tested is guaranteed. 33) Turn on the coaxial illumination source in the imaging lens and illuminate the optical spherical surface of the device under test. Then, adjust the distance between the imaging lens and the device under test by moving the linear axis one up and down until the light reflected back from the optical spherical surface of the device under test is imaged onto the image plane of the camera. Then, adjust the angle between the imaging lens and the rotation axis two so that the coaxial illumination light sweeps across the optical spherical surface of the device under test. Observe the size and shape of the reflected light on the image plane. If the size and shape of the reflected light on the image plane change with the angle between the imaging lens and the rotation axis two, the height of the sample fixture needs to be raised / lowered until the size and shape of the reflected light on the image plane no longer change when the angle between the imaging lens and the rotation axis two is adjusted. At this time, the center of the optical spherical surface under test falls on the extension line of the rotation axis one. This is the concentricity adjustment. 34) Fine-tune the XY fine-tuning mechanism on the sample fixture so that the optical axis of the component under test is vertically upward, and repeat step 32) so that the imaging lens can achieve clear imaging of the spherical edge of the component under test. At this point, the conditions for scanning and detecting the optical spherical surface are met. In step 4), the arc from the edge to the center of the component under test is divided into n broken line segments with an arc height ≤ the depth of field of the imaging lens.

2. The method of claim 1, wherein: The camera is either an area scan camera or a line scan camera.

3. The method for rotating and scanning the surface quality of a general-purpose optical element according to claim 1 or 2, characterized in that: The sample holder is also equipped with a leveling adjustment mechanism.

Images