A method of commissioning a test apparatus
By setting up an infinity-area reflector assembly and aperture adjustment device in the inspection equipment, the optical axis alignment process is simplified, the problem of decreased inspection accuracy caused by optical axis misalignment in the optical inspection system is solved, and the precise alignment of the illumination module, tube lens module and stage is achieved, thereby improving inspection accuracy and reducing production costs.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- ZHEJIANG SHUANGYUAN TECH CO LTD
- Filing Date
- 2026-02-05
- Publication Date
- 2026-05-19
AI Technical Summary
Existing testing equipment suffers from image position shift due to optical axis misalignment in optical testing systems, affecting testing accuracy. Furthermore, the debugging process is complex, making it difficult to achieve precise alignment of the illumination module, telescope module, and stage.
By setting an infinity-area reflector assembly on the end face of the telescope module away from the camera, a transmission imaging branch is formed by using reflected light. By adjusting the aperture and corresponding components, the first and second light spots are made to coincide, thus achieving the optical axis alignment between the illumination module and the telescope module. Vertical alignment between the stage and the telescope module is achieved through stage motion control.
It simplifies the debugging process, reduces debugging difficulty, improves the detection accuracy of the testing equipment, and reduces production costs, achieving efficient alignment of the optical inspection system.
Smart Images
Figure CN121633113B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of semiconductor wafer defect detection technology, and in particular to a debugging method for a detection device. Background Technology
[0002] Wafer inspection equipment needs to process dense image information. In order to efficiently extract pattern features and avoid splicing misalignment, its optical inspection system must meet the requirements of good illumination uniformity, full field of view magnification and image quality consistency. If the optical axis (principal ray) of the optical inspection system is offset, it will cause the image position to shift, which in turn will lead to a decrease in inspection accuracy.
[0003] Patent CN119846854A discloses a method for adjusting a detection device. The detection device, from object side to image side, includes an objective lens, a beam splitter, a telescope, and a detector, and also includes a Kohler illumination module. An illumination beam exits from the Kohler illumination module, passes through the beam splitter, and reaches the objective lens. When the object to be tested is positioned on the side of the objective lens away from the beam splitter, the illumination beam exiting the objective lens is reflected to obtain a reflected beam. The reflected beam passes sequentially through the objective lens, beam splitter, and telescope to the detector. An aperture stop is inserted into the Kohler illumination module, and an auxiliary lens is placed between the telescope and the detector. The detector then obtains the first spot position of the light spot formed by the aperture stop at the entrance pupil of the objective lens. When the Kohler illumination module does not provide an illumination beam and the light source is used as the object to be tested, the detector obtains the second spot position of the light spot at the entrance pupil of the objective lens. The position of the aperture stop is adjusted based on the first and second spot positions to align the illumination optical axis and the imaging optical axis. However, this method can only achieve the coincidence of the exit window of the Kohler illumination module and the entrance pupil of the objective lens. For an infinite distance microscopic optical system that conforms to y=f*tanθ, perfect optical path alignment and adjustment requires ensuring that y (where y is the entrance pupil of the objective lens, i.e., the exit window of the Kohler illumination) coincides, which is the pupil window matching condition mentioned in the patent text. More importantly, it also requires ensuring the coincidence of tanθ (angular frequency domain, i.e., optical axis), that is, the angle of the principal ray illuminating the entrance pupil of the objective lens must also be parallel to the optical axis of the objective lens. However, this patent text can only achieve the coincidence of the exit window of the Kohler illumination module and the entrance pupil of the objective lens, and the alignment process requires the movement of the light source and complex pixel coordinate calculations. In addition, the matching between the illumination optical axis and the wafer stage surface, and between the objective lens and the lens barrel, is also particularly important for the accuracy of the inspection equipment. Summary of the Invention
[0004] This invention provides a debugging method and debugging components for a testing device, which can further reduce the debugging difficulty of the testing device.
[0005] A method for debugging a testing device, the testing device comprising an illumination module and an imaging module; the illumination module comprising an aperture; the imaging module comprising a camera and a telescope module; the method comprising:
[0006] An infinity-area reflector assembly is provided on the end face of the telescope module away from the camera;
[0007] The illumination module is controlled to output a light beam, which then passes through the telescope module to the infinity reflector assembly and forms reflected light.
[0008] The reflected light is split to form a transmission imaging branch, and the transmission imaging branch forms a first light spot in the field of view of the camera.
[0009] Adjust the aperture in the lighting module to obtain a reflected image of the same origin as the first light spot in the light-blocking area of the corresponding aperture;
[0010] The intensity of the light beam is enhanced or the exposure time of the camera is increased, so that the backscattered light of the reflected image forms a second light spot in the field of view of the camera;
[0011] Adjust the corresponding components in the illumination module and the telescope module so that the first light spot and the second light spot overlap;
[0012] Adjust the corresponding components in the lighting module and the infinity reflector assembly to make the optical axis of the lighting module coincide with the optical axis of the telescope module.
[0013] Furthermore, the aperture stop includes an aperture stop and a field stop, and the illumination module also includes a surface light source and a reflector; a semi-reflective lens is provided inside the tube lens module;
[0014] An infinity-area reflector assembly is disposed on the output optical path of the semi-reflective lens;
[0015] The surface light source is turned on by control. The light beam output by the surface light source is reflected by the aperture stop, field stop, mirror, semi-reflective lens and infinity region mirror assembly. The reflected light is then split by the semi-reflective lens to form a transmission imaging branch.
[0016] Further, adjusting the aperture in the illumination module to obtain a reflected image of the same origin as the first light spot in the light-blocking area of the corresponding aperture includes: adjusting the aperture of the field of view aperture to the minimum, and obtaining a reflected image of the same origin as the first light spot in the light-blocking area of the field of view aperture.
[0017] The backscattered light from the reflected image is reflected by the mirror and the semi-reflective lens to the infinity mirror assembly, forming a second light spot in the camera's field of view.
[0018] Further, adjusting the corresponding components in the illumination module and the telescope module to make the first light spot and the second light spot coincide includes:
[0019] The angles of the reflector and the semi-reflective lens are controlled and adjusted so that the first light spot and the second light spot coincide, thereby making the optical axis of the illumination module parallel to the optical axis of the tube lens module.
[0020] Furthermore, adjusting the corresponding components in the illumination module and the infinity-area reflector assembly to achieve alignment between the optical axis of the illumination module and the optical axis of the telescope module includes:
[0021] Adjust the aperture of the aperture stop to its minimum size to form a conjugate image of the aperture stop in the effective reflective area of the reflector assembly at infinity.
[0022] Adjust the infinity-area reflector assembly so that the conjugate image is located at the center of the effective reflective area of the infinity-area reflector assembly, thereby aligning the optical axis of the illumination module with the optical axis of the tube mirror module.
[0023] Furthermore, the detection device also includes a stage and a stage motion control module, and before controlling the illumination module to output the light beam, it further includes:
[0024] The stage motion control module makes the bearing surface of the stage nearly perpendicular to the optical axis of the telescope module.
[0025] Furthermore, after the first light spot and the second light spot overlap, the method further includes:
[0026] After adjusting the effective reflective area of the infinity region reflector assembly to its maximum, it is transferred to the bearing surface of the stage;
[0027] Adjust the pitch and yaw angles of the telescope module so that the first and second light spots overlap again, thus making the optical axis of the telescope module perpendicular to the bearing surface of the stage.
[0028] Furthermore, the imaging module also includes an objective lens;
[0029] After the first and second light spots overlap again, the process also includes:
[0030] Remove the infinity-edge reflector assembly;
[0031] A first pinhole aperture is provided between the camera and the telescope module, and a second pinhole aperture is provided on the end face of the telescope module away from the camera;
[0032] A point light source is provided on the bearing surface of the platform, and the point light source is turned on while the surface light source is turned off;
[0033] The platform motion control module controls the platform motion so that the camera captures the brightest spot of the point light source through the first and second pinhole apertures, while keeping the current position of the platform unchanged.
[0034] Remove the first and second pinhole apertures and record the position of the center pixel of the brightest spot.
[0035] Install the objective lens, and adjust the tube lens module and objective lens according to the center pixel position of the recorded brightest spot to make the optical axis of the objective lens and the tube lens module coincide.
[0036] Furthermore, the detection device also includes a telescope motion control module;
[0037] Adjusting the tube lens module and objective lens according to the center pixel position of the recorded brightest light spot to achieve optical axis alignment between the objective lens and the tube lens module includes:
[0038] The height of the telescope module is adjusted by the telescope motion control module so that the camera can focus on the point light source;
[0039] Adjust the position of the objective lens so that the midpoint of the point light source image coincides with the position of the center pixel, thereby aligning the optical axis of the objective lens with that of the tube lens module.
[0040] A testing equipment debugging component applied to the above method includes an infinity-area reflector assembly, an aperture adjustment component, and a component adjustment component;
[0041] The infinity-area reflector assembly is used to reflect the light beam output from the telescope module to form reflected light; the aperture adjustment component is used to adjust the aperture in the illumination module; the component adjustment component is used to adjust the corresponding components in the illumination module and the telescope module, as well as the infinity-area reflector assembly, so that the first light spot and the second light spot coincide and the optical axis of the illumination module and the optical axis of the telescope module coincide.
[0042] Furthermore, the aperture stop includes an aperture stop and a field stop, and the illumination module also includes a surface light source and a reflector; a semi-reflective mirror is provided in the tube lens module; and an infinity-area reflector assembly is disposed in the output optical path of the semi-reflective mirror.
[0043] Furthermore, the aperture adjustment component includes a field aperture adjustment component, used to adjust the light transmission aperture of the field aperture to its minimum, so as to obtain a reflected image of the same origin as the first light spot in the light-blocking area of the field aperture.
[0044] Furthermore, the component adjustment mechanism includes a first angle adjustment mechanism and a second angle adjustment mechanism, wherein the first angle adjustment mechanism is used to adjust the angle of the reflector, and the second angle adjustment mechanism is used to adjust the angle of the semi-reflective mirror.
[0045] Furthermore, the component adjustment element is also used to adjust the light-transmitting aperture of the aperture stop to the minimum, form a conjugate image of the aperture stop in the effective reflective area of the infinity-area reflector assembly, and adjust the infinity-area reflector assembly so that the conjugate image is located at the center of the effective reflective area of the infinity-area reflector assembly, thereby realizing the optical axis of the illumination module and the optical axis of the tube mirror module coincide.
[0046] Furthermore, the testing equipment also includes a stage and a stage motion control module.
[0047] Furthermore, the debugging component also includes a telescope module adapter. After the first light spot and the second light spot overlap, the effective reflective area of the infinity region mirror assembly is adjusted to the maximum and then transferred to the bearing surface of the stage. The telescope module adapter is used to adjust the pitch angle and yaw angle of the telescope module so that the first light spot and the second light spot overlap again, thereby realizing that the optical axis of the telescope module is perpendicular to the bearing surface of the stage.
[0048] Furthermore, the imaging module also includes an objective lens; the adjustment assembly also includes a first pinhole aperture, a second pinhole aperture, and a point light source;
[0049] The first pinhole aperture is disposed between the camera and the telescope module, and the second pinhole aperture is disposed on the end face of the telescope module away from the camera; the point light source is disposed on the bearing surface of the stage;
[0050] After the first and second light spots overlap again, the infinity region reflector assembly is removed, the point light source is turned on, and the surface light source is turned off; the stage movement is controlled by the stage motion control module so that the camera captures the point light spot of the point light source through the first and second pinhole apertures at its brightest, while keeping the current position of the stage unchanged.
[0051] Remove the first and second pinhole apertures and record the position of the center pixel of the brightest spot.
[0052] Install the objective lens, and adjust the tube lens module and objective lens according to the center pixel position of the recorded brightest spot to make the optical axis of the objective lens and the tube lens module coincide.
[0053] The debugging method and debugging components for the testing equipment provided by this invention have at least the following beneficial effects:
[0054] (1) By setting up an infinity-area reflector assembly, the conjugate light spot generated by the aperture can be obtained simultaneously in the camera's field of view. During this process, the light source does not need to be moved. The parallelism of the optical axis is determined by the two light spots on the camera, and the two light spots are adjusted to make the optical axes of the illumination module and the telescope module parallel. There is no need to calculate the pixel coordinates, which reduces the difficulty of debugging. Furthermore, the infinity-area reflector assembly is adjusted to make the optical axis of the illumination module and the optical axis of the telescope module coincide.
[0055] (2) The optical calibration device has a simple structure and low cost: the calibration accessory consists of an infinity-area mirror assembly, two sub-mm apertures and a point light source, and the debugging process is simplified: there is no need to disassemble and assemble complex debugging fixtures, the calibration accessory is easy to install, and the production cost is reduced;
[0056] (3) It can not only make the optical axes of the illumination module and the tube lens module coincide, but also make the bearing surface of the stage perpendicular to the optical axis of the tube lens module and the objective lens coincide with the optical axis of the tube lens module, thereby improving the detection accuracy of the detection equipment;
[0057] (4) This method can also be used to determine the perpendicular relationship between the optical detection system and the surface of the object being measured. Attached Figure Description
[0058] Figure 1 This is a flowchart of one embodiment of the debugging method for the testing equipment provided by the present invention.
[0059] Figure 2 This is a schematic diagram of one embodiment of the debugging method for the detection equipment provided by the present invention.
[0060] Figure 3 This is a schematic diagram of the structure of one embodiment of the testing equipment in the debugging method of the testing equipment provided by the present invention.
[0061] Figure 4 This is a schematic diagram illustrating the principle of forming the first light spot in the debugging method of the detection equipment provided by the present invention.
[0062] Figure 5 This is a schematic diagram illustrating the principle of forming a reflected image in the debugging method of the detection equipment provided by the present invention.
[0063] Figure 6 This is a schematic diagram illustrating the principle of forming a second light spot in the debugging method of the detection equipment provided by the present invention.
[0064] Figure 7 A schematic diagram of the first and second light spots formed in the debugging method of the detection equipment provided by the present invention.
[0065] Figure 8 This is a schematic diagram showing the overlap of the first and second light spots formed in the debugging method of the detection equipment provided by the present invention.
[0066] Figure 9a This is a schematic diagram illustrating the angular mismatch between the reflector and the semi-reflective lens in the debugging method of the detection equipment provided by the present invention.
[0067] Figure 9b This is a schematic diagram showing the misalignment of the illumination module and the telescope module in the direction perpendicular to the optical axis in the debugging method of the detection equipment provided by the present invention.
[0068] Figure 9c This is a schematic diagram showing the alignment of the illumination optical axis and the tube lens optical axis in the debugging method of the detection equipment provided by the present invention.
[0069] Figure 10 This is a schematic diagram of adjusting the conjugate image in the debugging method of the detection equipment provided by the present invention.
[0070] Figure 11 This is a schematic diagram illustrating the relationship between the stage and the telescope module in the debugging method of the testing equipment provided by the present invention.
[0071] Figure 12 This is a schematic diagram showing that the optical axis of the telescope module is perpendicular to the stage in the debugging method of the detection equipment provided by the present invention.
[0072] Figure 13 A schematic diagram showing the addition of a pinhole aperture and a point light source to the debugging method of the detection equipment provided by the present invention.
[0073] Figure 14 This is a schematic diagram showing that the optical axis of the tube lens module and the optical axis of the objective lens do not coincide in the debugging method of the detection equipment provided by the present invention.
[0074] Figure 15 This is a schematic diagram showing the alignment of the optical axis of the tube lens module and the optical axis of the objective lens in the debugging method of the detection equipment provided by the present invention. Detailed Implementation
[0075] To better understand the above technical solutions, the following will provide a detailed explanation of the technical solutions in conjunction with the accompanying drawings and specific implementation methods.
[0076] refer to Figure 1 and Figure 2 In some embodiments, a debugging method for a detection device is provided, the detection device including an illumination module 1 and an imaging module 2; the illumination module 1 includes an aperture; the imaging module 2 includes a camera 21 and a telescope module 22; the method includes:
[0077] S1. An infinity-area reflector assembly 3 is set on the end face of the telescope module 22 away from the camera 21;
[0078] S2. Control the lighting module 1 to output a light beam, so that the light beam reaches the infinity reflector assembly 3 through the tube lens module 22 and forms reflected light;
[0079] S3. The reflected light is split to form a transmission imaging branch, and the transmission imaging branch forms a first light spot in the field of view of the camera.
[0080] S4. Adjust the aperture in the lighting module to obtain a reflected image that is of the same origin as the first light spot in the light-blocking area of the corresponding aperture;
[0081] S5. Control the enhancement of the intensity of the light beam or control the increase of the camera's exposure time, so that the backscattered light of the reflected image forms a second light spot in the camera's field of view;
[0082] S6. Adjust the corresponding components in the illumination module and the telescope module so that the first light spot and the second light spot overlap.
[0083] S7. Adjust the corresponding components in the lighting module 1 and the infinity reflector assembly 3 to make the optical axis of the lighting module and the optical axis of the tube mirror module coincide.
[0084] Specifically, refer to Figure 3 The illumination module 1 includes a surface light source 11, an aperture stop 12, a field stop 13, and a reflector 14; the tube lens module 22 is equipped with a semi-reflective lens 221; in addition, the detection device also includes an objective lens 4.
[0085] Aperture stop 12, field stop 13, and reflector 14 are sequentially arranged in the optical path of the beam emitted from surface light source 11. In some embodiments, illumination module 1 may further include a first lens 15 and a second lens 16, wherein the first lens 15 is disposed between aperture stop 12 and field stop 13, and the second lens 16 is disposed in the reflected optical path of reflector 14. A third lens 222 may also be disposed in tube lens module 22, between camera 21 and semi-reflective mirror 221.
[0086] The working principle of the testing equipment is as follows: The light beam emitted by the surface light source 11 passes sequentially through the aperture stop 12, the first lens 15, and the field stop 13 to the reflecting mirror 14. The reflecting mirror 14 reflects the light to the second lens 16, and then the light exits through the second lens 16 to the semi-reflective mirror 221. The semi-reflective mirror 211 reflects the light again, and the light passes through the objective lens 4 to the stage carrying the wafer to be tested. The probe light from the stage passes through the objective lens 4, the semi-reflective mirror 211, and the third lens 222 to the camera 21 for imaging.
[0087] For wafer inspection equipment, the probe light, after being reflected from the surface of the wafer under test, needs to return along the same path to the objective lens to fill the maximum range of light (NA) of the objective lens, thus achieving the best optical resolution of the optical system. This requires that the optical axis of the objective lens be perpendicular to the surface of the wafer under test, and that the illumination module, the telescope module, and the objective lens be properly matched.
[0088] In step S1, an infinity-area reflector assembly is set in the output optical path of the telescope module. The optical expression of the infinity-area reflector is as follows:
[0089] Y= f *sinθ;
[0090] Where Y represents the outline of the image. f Let θ be the focal length of the telescope module, and θ be the angle of the principal ray. The left side of the equation represents the spatial domain, which represents the outline of the image, while the right side represents the frequency domain, which represents the infinite region of the telescope module.
[0091] The infinity region reflector assembly 3 is positioned on the output optical path of the semi-reflective mirror 3.
[0092] Further, in step S2, the surface light source 11 is turned on and the beam output by the surface light source 11 passes through the aperture stop 12, the field stop 13, the mirror 14, the semi-reflective lens 221 and the infinity region mirror assembly 3 to form reflected light.
[0093] In step S3, the reflected light is split by the semi-reflective lens 211 to form a transmission imaging branch, and the transmission imaging branch forms the first light spot in the field of view of the camera.
[0094] Specifically, refer to Figure 4 The reflected light from the field stop 13 via the mirror 14 is split at the semi-reflective lens 221 to form a transmission imaging branch. The transmission imaging branch forms a first spot A in the field of view of the camera 21. The first spot A is the first-order reflection conjugate image of the transmitted light from the field stop 13.
[0095] Further, in step S4, adjusting the aperture in the illumination module 1 to obtain a reflected image of the same origin as the first light spot in the light-blocking area of the corresponding aperture includes:
[0096] Adjust the aperture of the field stop 13 to its minimum, and obtain a reflected image B that is homologous to the first light spot A in the shaded area of the field stop 13.
[0097] Specifically, refer to Figure 5 When the aperture of the field stop 13 is adjusted to its minimum, a reflected image B of the same size as the aperture of the field stop will be received in the shaded area of the field stop 13. This reflected image B will then emit backscattered light.
[0098] Further, in step S5, the intensity of the light beam is increased or the camera's exposure time is increased. The backscattered light from the reflected image B passes through the reflector 14 and the semi-reflective mirror 221 to the infinity-area reflector assembly 3, and is then reflected by the infinity-area reflector assembly 3 to form a second light spot C in the camera's field of view, such as... Figure 6 As shown.
[0099] refer to Figure 7 In the camera's field of view, the first spot A and the second spot C are the same size and mirror images, and the brightness of the second spot C is lower than that of the first spot A. According to the reversibility of light, the conjugate images of the two field stops, the first spot A and the second spot C, are symmetrical about the normal of the mirror 14.
[0100] Further, in step S5, adjusting the corresponding components in the illumination module and the telescope module to make the first light spot and the second light spot coincide includes:
[0101] The angles of the reflector 14 and the semi-reflective lens 221 are controlled and adjusted so that the first light spot A and the second light spot C coincide.
[0102] Specifically, adjusting the angles of the semi-reflective mirror 221 and the reflecting mirror 14 will make the principal ray of the aperture at the semi-reflective mirror 221 parallel to the optical axis of the tube lens module. At this time, the conjugate images of the two apertures of the first light spot A and the second light spot C will coincide, as shown below. Figure 8 As shown. A method for accurately determining the overlap of light spots can be developed to create a light spot center recognition algorithm, achieving sub-pixel alignment accuracy. Under normal circumstances, the light spots can be determined by visually observing the magnified image of each pixel, achieving single-pixel accuracy.
[0103] The mismatch in angle between the reflector 14 and the semi-reflective mirror 221 results in a situation where the optical axis of the illumination module is parallel to but does not coincide with the optical axis of the telescope module, such as... Figure 9a Due to the misalignment of the illumination module 1 and the telescope module 22 in the direction perpendicular to the optical axis, the optical axis of the illumination module is parallel to but does not coincide with the optical axis of the telescope module, such as... Figure 9b .
[0104] In this embodiment, the optical axis of the illumination module coincides with the optical axis of the telescope module, meaning that the optical axis of the illumination module and the optical axis of the telescope module can be aligned to the same straight line. The optical axis of the illumination module is parallel to but does not coincide with the optical axis of the telescope module, meaning that in space, the optical axis of the illumination module and the optical axis of the telescope module do not intersect, but cannot be aligned to the same straight line.
[0105] If the first light spot A and the second light spot C coincide, it means that the optical axis of the illumination module is parallel to the optical axis of the telescope module, but they do not necessarily coincide. Therefore, further adjustments are needed to make the optical axis of the illumination module coincide with the optical axis of the telescope module.
[0106] Adjusting the corresponding components in the lighting module and the infinity-area reflector assembly 3 to achieve alignment between the optical axis of the lighting module and the optical axis of the telescope module includes:
[0107] Adjust the aperture stop 12 to its minimum size; for example, the minimum aperture stop of a conventional aperture stop is 1 mm. (Reference) Figure 10 A conjugate image D of the aperture stop 12 is formed in the effective reflection area of the infinity-area mirror assembly. The adjustable aperture stop is adjusted so that the conjugate image D is located at the center of the effective reflection area of the infinity-area mirror assembly, thus aligning the optical axis of the illumination module with that of the telescope module. Furthermore, fine-tuning can be performed again: the effective reflection area of the mirror 14 is gradually reduced to near the optical axis, and the positions of the semi-reflective mirror 221 and the mirror 14 are readjusted to further ensure that the optical axis of the illumination module coincides with that of the telescope module. Figure 9c .
[0108] In some embodiments, the infinity region reflector assembly 3 may include an infinity region reflector and an adjustable aperture, wherein the effective reflective area of the infinity region reflector assembly is the light-transmitting area of the adjustable aperture.
[0109] In some embodiments, the infinity region reflector assembly 3 may also have 2-3 infinity region reflectors, and the effective reflective areas of the 2-3 infinity region reflectors are concentric and of different sizes.
[0110] Taking an infinity-area reflector and an adjustable aperture as an example, such as Figure 10 As shown, D is the conjugate image of the aperture stop on the infinity-area mirror with an adjustable aperture stop, F is the light-blocking area of the aperture stop, and G is the effective reflective area of the infinity-area mirror with an adjustable aperture stop. The coaxial relationship between the aperture stop and the telescope module is guaranteed by machining precision, such as coaxiality < 0.01 mm. The perpendicularity between the infinity-area mirror with an adjustable aperture stop and the optical axis of the telescope module is guaranteed by machining precision, for example, perpendicularity < 0.02 mm. The size of the effective reflective surface of the infinity-area mirror with an adjustable aperture stop does not affect the outlines of the first spot A and the second spot C, but only affects the brightness and sharpness of the outline edges; that is, it does not affect the overlap determination (i.e., high-frequency information reflects object details, and low-frequency information reflects object outlines).
[0111] The misalignment between the positions of the first light spot A and the second light spot C is used as a visual criterion for determining whether the illumination optical axis is parallel to the telescope optical axis.
[0112] Furthermore, in some embodiments, reference is made to... Figure 3The testing equipment also includes a stage motion control module 5, a telescope motion control module 6, and a stage 7. The stage motion control module 5 controls the horizontal movement of the stage 7, and the telescope motion control module 6 controls the vertical movement of the telescope module.
[0113] Before controlling the lighting module to output the light beam, the following is also included:
[0114] The stage motion control module makes the bearing surface of the stage nearly perpendicular to the optical axis of the telescope module.
[0115] Furthermore, after the first light spot and the second light spot overlap, the method further includes:
[0116] S7. After adjusting the effective reflective area of the infinity region reflector assembly 3 to its maximum, transfer it to the bearing surface of the stage 7.
[0117] S8. Adjust the pitch and yaw angles of the telescope module 22 so that the first and second light spots overlap again, thereby making the optical axis of the telescope module 22 perpendicular to the bearing surface of the stage.
[0118] Specifically, refer to Figure 11 The infinity region mirror assembly below the telescope module 22 is transferred to the surface of the stage 7. The parallelism of the upper and lower surfaces of the infinity region mirror assembly 3 is good. If the parallelism is ≤0.01°, then the normal of the infinity region mirror assembly 3 represents the normal of the surface of the stage 7.
[0119] Adjusting the pitch and yaw of the telescope module 02, the position (incident direction) of the second light spot C in the image of camera 21 is fixed, while the position (reflection direction) of the first light spot A changes with the angle between the normal of the stage 7 and the optical axis of the telescope module. When the first light spot A coincides with the second light spot C, as... Figure 12 This serves as a visual criterion for determining whether the optical axis of the telescope module 22 is perpendicular to the surface of the stage 7.
[0120] Furthermore, after the first and second light spots overlap again, the process also includes:
[0121] S9. Remove the infinity zone reflector assembly;
[0122] S10. A first pinhole aperture is provided between the camera and the telescope module, and a second pinhole aperture is provided on the end face of the telescope module away from the camera.
[0123] S11. A point light source is provided on the bearing surface of the platform, and the point light source is turned on while the surface light source is turned off;
[0124] S12. The platform is moved by the platform motion control module so that the camera captures the brightest spot of the point light source through the first and second pinhole apertures, and the current position of the platform remains unchanged.
[0125] S13. Remove the first and second pinhole apertures and record the position of the center pixel of the brightest spot.
[0126] S14. Install objective lens 4, and adjust the tube lens module and objective lens according to the center pixel position of the recorded brightest light spot to make the optical axis of the objective lens and the tube lens module coincide.
[0127] Specifically, in step S14, adjusting the tube lens module and objective lens according to the center pixel position of the recorded brightest light spot to achieve optical axis alignment between the objective lens and the tube lens module includes:
[0128] The height of the telescope module is adjusted by the telescope motion control module so that the camera can focus on the point light source;
[0129] Adjust the position of the objective lens so that the midpoint of the point light source image coincides with the position of the center pixel, thereby aligning the optical axis of the objective lens with that of the tube lens module.
[0130] Specifically, a first pinhole diaphragm 8 and a second pinhole diaphragm 9 with a light-transmitting aperture of approximately 1 mm are respectively added between the camera 21 and the telescope module 22, and between the telescope module 22 and the objective lens 4. The concentricity of the first pinhole diaphragm 8, the second pinhole diaphragm 9, and the telescope module 22 is ensured by machining precision. A point light source 10 with a diameter of approximately 1 mm is placed on the stage 7, such as... Figure 13 As shown. Normally, after spatial filtering by the first pinhole aperture 8 and the second pinhole aperture 9, the camera 21 cannot receive information from the point light source 10. Driving the stage motion control module 6, the point light source 10 passes through the two pinholes of the first pinhole aperture 8 and the second pinhole aperture 9. At this time, the camera 21 can observe a brightest spot. Keeping the stage 7 in its current position unchanged, the first pinhole aperture 8 and the second pinhole aperture 9 are removed, and the pixel coordinates of this brightest spot on the camera 21 are recorded. The objective lens 4 is installed; the optical axis of the objective lens 4 does not coincide with the optical axis of the tube lens module 22, as shown... Figure 14 As shown, at this time, the conjugate image of the point light source 10 on camera 21 deviates from the pixel coordinate position. The drive lens motion control module 6 adjusts the height of the lens module so that the camera focuses on the light source 10. The position of the objective lens 4 is adjusted so that the coordinate position of the conjugate image of the point light source 10 on camera 21 is the same as the pixel coordinate position. At this time, the optical axis of the objective lens 4 coincides with that of the lens module, as shown. Figure 15 .
[0131] In some embodiments, a testing device debugging component for use in the above method is also provided, including an infinity region reflector assembly, an aperture adjustment component, and a component adjustment component;
[0132] The infinity-area reflector assembly is used to reflect the light beam output from the telescope module to form reflected light; the aperture adjustment component is used to adjust the aperture in the illumination module; the component adjustment component is used to adjust the corresponding components in the illumination module and the telescope module, as well as the infinity-area reflector assembly, so that the first light spot and the second light spot coincide and the optical axis of the illumination module and the optical axis of the telescope module coincide.
[0133] Furthermore, the aperture stop includes an aperture stop and a field stop, and the illumination module also includes a surface light source and a reflector; a semi-reflective lens is provided in the tube lens module; and an infinity-area reflector assembly is disposed in the output optical path of the semi-reflective lens.
[0134] Furthermore, the aperture adjustment component includes a field aperture adjustment component, used to adjust the light transmission aperture of the field aperture to its minimum, so as to obtain a reflected image of the same origin as the first light spot in the light-blocking area of the field aperture.
[0135] Furthermore, the component adjustment mechanism includes a first angle adjustment mechanism and a second angle adjustment mechanism, wherein the first angle adjustment mechanism is used to adjust the angle of the reflector, and the second angle adjustment mechanism is used to adjust the angle of the semi-reflective mirror.
[0136] Furthermore, the component adjustment element is also used to adjust the light-transmitting aperture of the aperture stop to the minimum, form a conjugate image of the aperture stop in the effective reflective area of the infinity-area reflector assembly, and adjust the infinity-area reflector assembly so that the conjugate image is located at the center of the effective reflective area of the infinity-area reflector assembly, thereby realizing the optical axis of the illumination module and the optical axis of the tube mirror module coincide.
[0137] Furthermore, the testing equipment also includes a stage motion control module, a telescope motion control module, and a stage.
[0138] Furthermore, the debugging component also includes a telescope module adapter. After the first light spot and the second light spot overlap, the effective reflective area of the infinity region mirror assembly is adjusted to the maximum and then transferred to the bearing surface of the stage. The telescope module adapter is used to adjust the pitch angle and yaw angle of the telescope module so that the first light spot and the second light spot overlap again, thereby realizing that the optical axis of the telescope module is perpendicular to the bearing surface of the stage.
[0139] Furthermore, the imaging module also includes an objective lens; the adjustment assembly also includes a first pinhole aperture, a second pinhole aperture, and a point light source;
[0140] The first pinhole aperture is disposed between the camera and the telescope module, and the second pinhole aperture is disposed on the end face of the telescope module away from the camera; the point light source is disposed on the bearing surface of the stage;
[0141] After the first and second light spots overlap again, the infinity region reflector assembly is removed, the point light source is turned on, and the surface light source is turned off; the stage movement is controlled by the stage motion control module so that the camera captures the point light spot of the point light source through the first and second pinhole apertures at its brightest, while keeping the current position of the stage unchanged.
[0142] Remove the first and second pinhole apertures and record the position of the center pixel of the brightest spot.
[0143] Install the objective lens, and adjust the tube lens module and objective lens according to the center pixel position of the recorded brightest light spot to make the optical axis of the objective lens and the tube lens module coincide.
[0144] The debugging method and debugging components for the testing equipment provided in the above embodiments have at least the following beneficial effects:
[0145] (1) By setting up an infinity-area reflector assembly, the conjugate light spot generated by the aperture can be obtained simultaneously in the camera's field of view. During this process, the light source does not need to be moved. The parallelism of the optical axis is determined by the two light spots on the camera, and the two light spots are adjusted to make the optical axes of the illumination module and the telescope module parallel. There is no need to calculate the pixel coordinates, which reduces the difficulty of debugging. Furthermore, the infinity-area reflector assembly is adjusted to make the optical axis of the illumination module and the optical axis of the telescope module coincide.
[0146] (2) The optical calibration device has a simple structure and low cost: the calibration accessory consists of an infinity-area mirror assembly, two sub-mm apertures and a point light source, and the debugging process is simplified: there is no need to disassemble and assemble complex debugging fixtures, the calibration accessory is easy to install, and the production cost is reduced;
[0147] (3) It can not only make the optical axes of the illumination module and the tube lens module coincide, but also make the optical axis of the tube lens module perpendicular to the stage bearing surface and the objective lens coincide with the optical axis of the tube lens module, thereby improving the detection accuracy of the detection equipment;
[0148] (4) This method can also be used to determine the perpendicular relationship between the optical detection system and the surface of the object being measured.
[0149] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the invention. Clearly, those skilled in the art can make various alterations and modifications to the invention without departing from its spirit and scope. Thus, if these modifications and modifications of the invention fall within the scope of the claims and their equivalents, the invention is also intended to include these modifications and modifications.
Claims
1. A debugging method for a testing device, characterized in that, The detection device includes an illumination module and an imaging module; the illumination module includes an aperture; the imaging module includes a camera and a telescope module; the method includes: An infinity-area reflector assembly is provided on the end face of the telescope module away from the camera; The illumination module is controlled to output a light beam, which then passes through the telescope module to the infinity-area reflector assembly and forms reflected light. The reflected light is split to form a transmission imaging branch, and the transmission imaging branch forms a first light spot in the field of view of the camera. Adjust the aperture in the lighting module to obtain a reflected image that is of the same origin as the first light spot in the light-blocking area of the corresponding aperture; The intensity of the light beam is enhanced or the exposure time of the camera is increased, so that the backscattered light of the reflected image forms a second light spot in the field of view of the camera; Adjust the corresponding components in the illumination module and the telescope module so that the first light spot and the second light spot overlap; The aperture stop includes an aperture stop, and the illumination module also includes a surface light source. Adjusting the corresponding components in the illumination module and the infinity-area reflector assembly, the optical axis of the illumination module and the optical axis of the telescope module are made coincident. Adjusting the aperture stop's aperture diameter to its minimum, a conjugate image of the aperture stop is formed in the effective reflective area of the infinity-area reflector assembly. Adjusting the infinity-area reflector assembly so that the conjugate image is located at the center of the effective reflective area of the infinity-area reflector assembly, thus aligning the optical axis of the illumination module and the optical axis of the telescope module.
2. The method according to claim 1, characterized in that, The aperture also includes a field aperture, and the illumination module also includes a reflector; the tube lens module is equipped with a semi-reflective lens. An infinity-area reflector assembly is disposed on the output optical path of the semi-reflective lens; The surface light source is turned on by control. The light beam output by the surface light source is reflected by the aperture stop, field stop, mirror, semi-reflective lens and the infinity region mirror assembly. The reflected light is then split by the semi-reflective lens to form a transmission imaging branch.
3. The method according to claim 2, characterized in that, Adjusting the aperture in the illumination module to obtain a reflected image of the same origin as the first light spot in the light-blocking area of the corresponding aperture includes: adjusting the aperture of the field of view aperture to the minimum, and obtaining a reflected image of the same origin as the first light spot in the light-blocking area of the field of view aperture. The backscattered light from the reflected image is reflected by the mirror and the semi-reflective lens to the infinity mirror assembly, forming a second light spot in the camera's field of view.
4. The method according to claim 2, characterized in that, Adjusting the corresponding components in the illumination module and the telescope module to make the first light spot and the second light spot coincide includes: The angles of the reflector and the semi-reflective lens are controlled and adjusted so that the first light spot and the second light spot coincide, thereby making the optical axis of the illumination module parallel to the optical axis of the tube lens module.
5. The method according to claim 1, characterized in that, The detection device also includes a stage and a stage motion control module. Before controlling the illumination module to output the light beam, it also includes: The stage motion control module makes the bearing surface of the stage nearly perpendicular to the optical axis of the telescope module.
6. The method according to claim 5, characterized in that, After the first and second light spots overlap, the method further includes: After adjusting the effective reflective area of the infinity region reflector assembly to its maximum, it is transferred to the bearing surface of the stage; Adjust the pitch and yaw angles of the telescope module so that the first and second light spots overlap again, thus making the optical axis of the telescope module perpendicular to the bearing surface of the stage.
7. The method according to claim 6, characterized in that, The imaging module also includes an objective lens; After the first and second light spots overlap again, the process also includes: Remove the infinity-edge reflector assembly; A first pinhole aperture is provided between the camera and the telescope module, and a second pinhole aperture is provided on the end face of the telescope module away from the camera; A point light source is provided on the bearing surface of the platform, and the point light source is turned on while the surface light source is turned off; The platform motion control module controls the platform motion so that the camera captures the brightest spot of the point light source through the first and second pinhole apertures, while keeping the current position of the platform unchanged. Remove the first and second pinhole apertures and record the position of the center pixel of the brightest spot. Install the objective lens, and adjust the tube lens module and objective lens according to the center pixel position of the recorded brightest spot to make the optical axis of the objective lens and the tube lens module coincide.
8. The method according to claim 7, characterized in that, The detection equipment also includes a telescope motion control module; Adjusting the tube lens module and objective lens according to the center pixel position of the recorded brightest light spot to achieve optical axis alignment between the objective lens and the tube lens module includes: The height of the telescope module is adjusted by the telescope motion control module so that the camera can focus on the point light source; Adjust the position of the objective lens so that the midpoint of the point light source image coincides with the position of the center pixel, thereby aligning the optical axis of the objective lens with that of the tube lens module.
9. The method according to claim 1, characterized in that, It also includes aperture adjustment components and component adjustment components; The aperture adjustment component is used to adjust the aperture in the lighting module to obtain a reflected image of the same origin as the first light spot in the light-blocking area of the corresponding aperture. The component adjustment component is used to adjust the corresponding components in the illumination module and the telescope module so that the first light spot and the second light spot overlap. The component adjustment mechanism is also used to adjust the corresponding components in the lighting module and the infinity-area reflector assembly to achieve the optical axis of the lighting module and the optical axis of the telescope module being aligned: adjusting the aperture stop to its minimum aperture to form a conjugate image of the aperture stop in the effective reflective area of the infinity-area reflector assembly; adjusting the infinity-area reflector assembly so that the conjugate image is located at the center of the effective reflective area of the infinity-area reflector assembly, thereby achieving the optical axis of the lighting module and the optical axis of the telescope module being aligned.