A control method for a detection system

Abstract

The application provides a control method of a detection system, the detection system comprising an illumination module, a first detection device, and a light splitting module and a first power adjustment module between the illumination module and the first detection device, the illumination module being configured to provide an illumination light beam, the first detection device being configured to detect a first surface to be detected to obtain a first detection signal, the light splitting module being configured to split the illumination light beam to obtain a first sub-light beam and a second sub-light beam, the first detection device being illuminated based on the first sub-light beam, and optical power detection being performed based on the second sub-light beam, so that the illumination and the optical detection can be considered, when the actual optical power exceeds a preset range, the optical power of the light beam passing through the first power adjustment module is adjusted to adjust the intensity of the first detection signal, and if the intensity of the first detection signal meets a preset condition, the adjustment of the optical power of the light beam passing through the first power adjustment module is stopped, and accurate adjustment of the optical power is realized.

Description

Technical Field

[0001] This application relates to the field of microscopic imaging, and in particular to a control method for a detection system. Background Technology

[0002] Currently, the surface to be tested can be inspected using testing equipment. During the inspection process, an illumination module is required to provide an illumination beam. High-precision testing equipment requires high environmental stability and illumination stability. In actual operation, if the intensity of the illumination beam changes, it can easily lead to inaccurate test results, reduced detection accuracy, and affect the stability and measurement accuracy of the testing equipment.

[0003] Currently, the methods for detecting the intensity of illumination beams typically employ a beam splitter to divide the beam into two parts. One part enters the detection device for illumination, while the other part enters the light intensity detection device for light intensity detection. This allows for simultaneous light intensity detection and device illumination. However, since light intensity detection and device illumination are separated into two different optical paths, disturbances may exist in the illumination optical path. Relying solely on the light intensity detection results to control the intensity of the illumination beam cannot guarantee the stability of the illumination of the detection device. Summary of the Invention

[0004] In view of this, the purpose of this application is to provide a control method for a detection system, which uses the detection results of the detection equipment as a verification item for optical power adjustment, ensuring the illumination stability in the detection system, and guaranteeing the system's stability and measurement accuracy. The specific solution is as follows:

[0005] On one hand, this application provides a control method for a detection system. The detection system includes an illumination module, a first detection device, and a beam splitting module and a first power adjustment module between the illumination module and the first detection device. The illumination module provides an illumination beam, the first detection device detects a first surface to be tested to obtain a first detection signal, and the beam splitting module splits the illumination beam to obtain a first sub-beam and a second sub-beam. The first sub-beam passes through the first power adjustment module and enters the first detection device, while the second sub-beam enters an optical power detection module. The optical power detection module detects the optical power of the incoming beam to obtain the actual optical power.

[0006] The method includes:

[0007] When the actual optical power exceeds the preset range, the optical power of the beam passing through the first power adjustment module is adjusted to adjust the intensity of the first detection signal;

[0008] If the intensity of the first detection signal meets the preset condition, the adjustment of the optical power of the beam passing through the first power adjustment module is stopped.

[0009] Optionally, adjusting the optical power of the beam passing through the first power adjustment module when the actual optical power exceeds a preset range includes:

[0010] When the actual optical power is less than the lower limit of the preset range, the required optical power is determined according to the lower limit of the preset range;

[0011] The optical power of the beam passing through the first power adjustment module is increased according to the required optical power.

[0012] Optionally, the illumination beam is linearly polarized, the first power adjustment module includes a polarizer, and increasing the optical power of the beam transmitted through the first power adjustment module according to the required optical power includes:

[0013] The required polarization direction of the polarizer is determined based on the required optical power.

[0014] According to the required polarization direction, the polarization direction of the polarizer is adjusted to increase the optical power of the light beam transmitted through the first power adjustment module.

[0015] Optionally, the first detection signal includes a first interference image, and the step of stopping the adjustment of the optical power of the beam transmitted through the first power adjustment module if the intensity of the first detection signal meets a preset condition includes:

[0016] If the contrast of the first interference image is within a preset contrast range, the adjustment of the optical power of the beam passing through the first power adjustment module is stopped.

[0017] Optionally, the first detection signal includes a first interferometric image, and the method further includes:

[0018] By fitting the actual optical power and the contrast of the first interference image, a first correspondence between optical power and image contrast is obtained;

[0019] The step of stopping the adjustment of the optical power of the beam passing through the first power adjustment module if the intensity of the first detection signal meets a preset condition includes:

[0020] If the adjusted actual optical power and the adjusted first interference image satisfy the first correspondence, and the contrast of the first interference image is within the preset contrast range, then the adjustment of the optical power of the beam passing through the first power adjustment module is stopped.

[0021] Optionally, the method further includes:

[0022] If the adjusted optical power and the adjusted first interference image do not satisfy the first correspondence, then a first alarm message is generated.

[0023] Optionally, the first correspondence is represented by the following formula:

[0024] y = -2.1062x 2 +3.2941x - 0.3366,

[0025] x represents optical power, and y represents image contrast.

[0026] Optionally, the beam splitting module is used to switch the working mode. When the working mode is the light transmission mode, the illumination beam passes through the beam splitting module to obtain a first sub-beam, and the first sub-beam passes through the first power adjustment module to enter the detection device. When the working mode is the reflection mode, the illumination beam is reflected by the beam splitting module to obtain a second sub-beam, and the second sub-beam enters the optical power detection module.

[0027] Optionally, the beam splitting module includes a semi-transparent and semi-reflective module, which includes a light transmission path and a reflective surface. The light transmission path includes a first surface and a second surface. The material between the first surface and the second surface is transparent. The light transmission path and the reflective surface alternately switch to the propagation path of the illumination beam, thereby switching the working mode of the semi-transparent and semi-reflective module.

[0028] When the light transmission path is switched to the propagation path of the illumination beam, the operating mode is the light transmission mode; when the reflective surface is switched to the propagation path of the illumination beam, the operating mode is the reflection mode.

[0029] Optionally, the semi-transparent and semi-reflective module rotates at a preset rate to periodically switch the light transmission path and the reflective surface to the propagation path of the illumination beam.

[0030] Optionally, the rotation axis of the semi-transparent and semi-reflective module is parallel to and does not coincide with the propagation path of the illumination beam. The semi-transparent and semi-reflective module includes a first part and a second part in a plane perpendicular to the rotation axis. The first part has a light-transmitting path, and the surface of the second part facing the illumination module is a reflective surface. The angle between the emitting surface and the rotation axis is less than 90°. When the semi-transparent and semi-reflective module rotates around the rotation axis, the first part and the second part alternately switch to the propagation path of the illumination beam.

[0031] Optionally, the rotation axis of the semi-transparent and semi-reflective module is perpendicular to the propagation direction of the illumination beam, and the semi-transparent and semi-reflective module has a first surface, a second surface, a third surface, and a fourth surface parallel to the rotation axis; the first surface and the second surface are opposite surfaces; the third surface and the fourth surface are opposite surfaces and are reflective surfaces.

[0032] Optionally, the rotational speed of the semi-transparent and semi-reflective module is such that a single sampling by the first detection device corresponds to at least one transmission mode and one reflection mode.

[0033] Optionally, the detection system further includes:

[0034] The second detection device is used to detect the second surface to be tested and obtain a second detection signal;

[0035] A master beam splitter is used to split the illumination beam into a first beam and a second beam, the first beam entering the first detection device and the second beam entering the second detection device;

[0036] The second power adjustment module between the main beam splitter and the second detection device;

[0037] The method further includes:

[0038] When the actual optical power exceeds a preset range, the optical power of the beam passing through the second power adjustment module is adjusted to adjust the intensity of the second detection signal;

[0039] If the intensity of the second detection signal meets the preset conditions, the adjustment of the optical power of the beam passing through the second power adjustment module is stopped.

[0040] Optionally, the second detection signal includes a second interference image, and the step of stopping the adjustment of the optical power of the beam transmitted through the second power adjustment module if the intensity of the second detection signal meets a preset condition includes:

[0041] If the contrast of the second interference image is within a preset contrast range, the adjustment of the optical power of the beam passing through the second power adjustment module is stopped.

[0042] Optionally, the second detection signal includes a second interferometric image, and the method further includes:

[0043] By fitting the actual optical power and the contrast of the second interference image, a second correspondence between optical power and image contrast is obtained;

[0044] The step of stopping the adjustment of the optical power of the beam passing through the second power adjustment module if the intensity of the second detection signal meets the preset condition includes:

[0045] If the adjusted actual optical power and the adjusted second interference image satisfy the second correspondence, and the contrast of the second interference image is within the preset contrast range, then stop adjusting the optical power of the beam passing through the second power adjustment module.

[0046] Optionally, the method further includes:

[0047] If the adjusted optical power and the adjusted second interference image do not satisfy the second contrast relationship, a second alarm message is generated.

[0048] Optionally, the first detection device includes a first reference mirror, a first beam expander, a first beam splitter, and a first detector. The first light beam is reflected by the first beam splitter and then passes through the first beam expander to illuminate the first reference mirror. A portion of the first light beam that passes through the first reference mirror illuminates a first test surface on the side of the first reference mirror away from the first beam expander and is reflected to obtain a first reflected light beam. The first reflected light beam passes through the first reference mirror, the first beam expander, and the first beam splitter to reach the first detector. A portion of the first light beam reflected by the first reference mirror serves as a second reflected light beam. The second reflected light beam passes through the first beam expander and the first beam splitter to reach the first detector. The first detector is used to acquire the interference information between the first reflected light beam and the second reflected light beam as the first detection signal; and / or,

[0049] The second detection device includes a second reference mirror, a second beam expander, a second beam splitter, and a second detector. The second beam is reflected by the second beam splitter and then passes through the second beam expander to illuminate the second reference mirror. A portion of the second beam that passes through the second reference mirror illuminates a second test surface located away from the second beam expander and is reflected to obtain a third reflected beam. The third reflected beam passes through the second reference mirror, the second beam expander, and the second beam splitter to reach the second detector. A portion of the second beam reflected by the second reference mirror serves as a fourth reflected beam. The fourth reflected beam passes through the second beam expander and the second beam splitter to reach the second detector. The second detector is used to acquire the interference information between the third and fourth reflected beams as the second detection signal.

[0050] Optionally, if the illumination beam is linearly polarized, the first test surface and the second test surface are surfaces on different sides of the same test object, the first detection device further includes a first quarter-wave plate between the first beam expander and the first beam splitter, and the second detection device further includes a second quarter-wave plate between the second beam expander and the second beam splitter. The fast axis directions of the first quarter-wave plate and the second quarter-wave plate are orthogonal, and the first beam splitter and the second beam splitter are polarizing beam splitters.

[0051] Optionally, the detection system further includes:

[0052] The main collimator is located between the illumination module and the main beam splitter;

[0053] The first converging lens and the first optical fiber between the main beam splitter and the first detection device;

[0054] The second converging mirror and the second optical fiber are located between the main beam splitter and the second detection device.

[0055] Optionally, the detection system further includes:

[0056] The reflector between the beam splitter and the optical power detection module is used to reflect the light beam reflected by the beam splitter back to the optical power detection module.

[0057] This application provides a control method for a detection system. The detection system includes an illumination module, a first detection device, and a beam splitting module and a first power adjustment module between the illumination module and the first detection device. The illumination module provides an illumination beam, the first detection device detects a first surface to be tested to obtain a first detection signal, and the beam splitting module splits the illumination beam to obtain a first sub-beam and a second sub-beam. The first sub-beam passes through the first power adjustment module and enters the first detection device, while the second sub-beam enters an optical power detection module. The optical power detection module detects the optical power of the incoming beam to obtain the actual optical power. Thus, based on the first sub-beam, the optical power can be... The first detection device is illuminated, and optical power detection can be performed based on the second sub-beam. Therefore, both illumination and optical detection can be taken into account. When the actual optical power exceeds the preset range, the optical power of the beam passing through the first power adjustment module is adjusted to adjust the intensity of the first detection signal. If the intensity of the first detection signal meets the preset condition, the adjustment of the optical power of the beam passing through the first power adjustment module is stopped. In this way, the optical power can be adjusted based on the actual optical power, and the intensity of the first detection signal is used as a verification item for the optical power adjustment, so that the adjustment of the optical power can make the intensity of the first detection signal meet the preset condition, thus achieving accurate adjustment of the optical power. Attached Figure Description

[0058] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0059] Figure 1 A flowchart illustrating a control method for a detection system provided in an embodiment of this application is shown.

[0060] Figure 2 This paper shows a schematic diagram of the structure of a detection system provided in an embodiment of this application;

[0061] Figure 3 A schematic diagram of a first interference image provided in an embodiment of this application;

[0062] Figure 4 A fitting schematic diagram provided for an embodiment of this application;

[0063] Figure 5 and Figure 6 This is a schematic diagram of the operation of a beam splitter module provided in an embodiment of this application;

[0064] Figure 7 and Figure 8 This is a schematic diagram of another beam splitting module provided in an embodiment of this application;

[0065] Figure 9 A schematic diagram of another detection system provided in an embodiment of this application is shown. Detailed Implementation

[0066] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, the specific embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0067] Many specific details are set forth in the following description in order to provide a full understanding of this application. However, this application may also be implemented in other ways different from those described herein. Those skilled in the art can make similar extensions without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0068] Secondly, this application provides a detailed description in conjunction with schematic diagrams. When detailing the embodiments of this application, for ease of explanation, the cross-sectional views illustrating the device structure may be partially enlarged, not adhering to the usual scale. Furthermore, the schematic diagrams are merely examples and should not limit the scope of protection of this application. In addition, actual fabrication should include three-dimensional spatial dimensions of length, width, and depth.

[0069] For ease of understanding, the control method of a detection system provided in the embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0070] This application also provides a control method for a detection system, which is applied to the detection system, and refers to... Figure 1 The diagram shown is a flowchart illustrating a control method for a detection system provided in an embodiment of this application. The method may include the following steps.

[0071] S101, when the actual optical power exceeds the preset range, adjust the optical power of the beam passing through the first power adjustment module to adjust the intensity of the first detection signal.

[0072] refer to Figure 2The diagram shown is a structural schematic of a detection system provided in an embodiment of this application. The detection system includes an illumination module 100, a first detection device 300, and a beam splitting module 204 and a first power adjustment module 207 between the illumination module 100 and the first detection device 300.

[0073] The illumination module 100 is used to provide an illumination beam to illuminate the field of view of the first detection device 300. The illumination module 100 may be, for example, a laser. The illumination beam is determined according to the type of the first detection device 300. If the first detection device 300 is an interferometer, the illumination beam is usually monochromatic light or a composite light of multiple wavelengths. If the first detection device 300 is another instrument, the illumination beam may be a composite light of multiple wavelengths.

[0074] The first detection device 300 is used to detect the first surface to be tested and obtain a first detection signal. The first detection device 300 can be an interferometer or other detection device. When the detection accuracy of the first detection device 300 is high, the illumination module 100 needs to provide a stable illumination beam. For example, the light power of the illumination beam entering the first detection device 300 needs to be within a preset range.

[0075] The beam splitter module 204 splits the illumination beam to obtain a first sub-beam and a second sub-beam. The first sub-beam passes through the first power adjustment module 207 and enters the first detection device 300. The second sub-beam enters the optical power detection module 206, which detects the optical power of the incoming beam to obtain the actual optical power. Thus, the first detection device can be illuminated based on the first sub-beam, and optical power detection can be performed based on the second sub-beam, thereby simultaneously providing illumination and optical detection.

[0076] In this embodiment, when the actual optical power detected by the optical power detection module 206 exceeds the preset range, it indicates that the output power of the lighting module has decayed to an unacceptable level. In this case, the optical power of the beam passing through the first power adjustment module can be adjusted to maintain the stability of the lighting environment throughout the product lifecycle and ensure the measurement accuracy of the stability of the detection system.

[0077] Specifically, when the actual optical power is less than the lower limit of a preset range, the optical power of the beam passing through the first power adjustment module is increased. In practice, when the actual optical power is less than the lower limit of the preset range, the required optical power can be determined based on the lower limit of the preset range; the optical power of the beam passing through the first power adjustment module is increased based on the required optical power, thereby increasing the optical power of the beam, improving the signal quality of the first detection signal, and enhancing detection accuracy. The preset range can be determined based on historical detection optical power and stored as a constant in the device to achieve optical power adjustment.

[0078] S102, if the intensity of the first detection signal meets the preset conditions, stop adjusting the optical power of the beam passing through the first power adjustment module.

[0079] In this embodiment, a first detection signal can also be acquired. The intensity of the first detection signal is used to determine whether the optical power adjustment of the beam meets the requirements. If the intensity of the first detection signal meets the preset conditions, it indicates that the quality of the first detection signal is high. Therefore, the adjustment of the optical power of the beam passing through the first power adjustment module can be stopped. In this way, the optical power can be adjusted based on the actual optical power. The intensity of the first detection signal is used as a verification item for the optical power adjustment. The quality of the optical power and the detection signal can be detected simultaneously for dynamic compensation control. This ensures that the adjustment of the optical power can make the intensity of the first detection signal meet the preset conditions, thereby achieving accurate adjustment of the optical power, improving the system's adaptability, ensuring the stability of the illumination imaging of the detection system, and guaranteeing the system's measurement accuracy.

[0080] Due to their high resolution, high accuracy, and unique characteristics, optical power detectors accurately detect changes in the laser, providing a more intuitive and precise feedback on illumination state changes. However, the illumination fringes required by the interferometer are characterized by the contrast ratio (SNR) of the interferogram. Directly using the SNR of the interferogram to characterize changes in the illumination mode is insufficiently accurate. This is because various perturbation errors exist in the system, such as test repeatability, vibration, and environmental disturbances, all of which affect the SNR value. Therefore, the SNR value cannot be used to characterize changes in the illumination laser or illumination mode. Thus, it is necessary to establish a relationship between an optical power meter that directly characterizes laser changes and the SNR that directly characterizes the interferometric illumination effect, indirectly verifying the influence of illumination and interferometric effects. This can greatly help in maintaining stable illumination adjustment.

[0081] When the first detection signal includes the first interferometric image, if the contrast ratio (SNR) of the first interferometric image is within a preset contrast ratio range, it indicates that the first interferometric image can accurately reflect the characteristics of the interference fringes. Therefore, the intensity of the first detection signal can be considered to meet the preset condition, and the adjustment of the optical power of the beam passing through the first optical power adjustment module can be stopped. Using the contrast ratio of the first interferometric image as a verification item helps to obtain a higher quality first interferometric image and improve detection accuracy. The preset contrast ratio range can be determined based on the contrast ratio of historical images and stored as a constant in the device to verify the optical power adjustment.

[0082] The first interferometric image is obtained after the actual optical power is measured. The first interferometric image and the actual optical power can be obtained within different sampling periods, and the sampling period interval between their acquisition does not exceed a preset number. This allows the first interferometric image to reflect the adjustment effect of the optical power relatively promptly. In specific implementation, the actual optical power and the interferometric image within the same sampling period can be saved as a basis for subsequent comparison. This achieves synchronous detection of optical power and the interferometric image, enabling dynamic compensation of the optical power, ensuring the stability of the system's illumination imaging, and guaranteeing the system's measurement accuracy.

[0083] The contrast of the first interferometric image can be the contrast within a fixed region of the first interferometric image, and the contrast within this fixed region represents the overall contrast of the first interferometric image. (Reference) Figure 3 As shown, this is a schematic diagram of a first interference image provided in an embodiment of this application, where the contrast in the fixed region 1001 (the region within the rectangle formed by white lines) is 0.8958.

[0084] When the first detection signal includes the first interference image, the actual optical power and the contrast of the first interference image can also be fitted to obtain the first correspondence between optical power and image contrast. If the adjusted actual optical power and the adjusted first interference image satisfy the first correspondence, and the contrast of the first interference image is within the preset contrast range, it indicates that the first interference image can accurately reflect the characteristics of the interference fringes, and the correspondence between the actual optical power and the contrast of the first interference image is maintained. The detection system is functioning normally, and the intensity of the first detection signal can be considered to meet the preset conditions. The adjustment of the optical power of the beam passing through the first optical power adjustment module can be stopped. Using the contrast of the first interference image and the first correspondence as verification items is beneficial to obtaining a high-quality first interference image. At the same time, the function of the detection system can be verified, and the detection accuracy can be improved.

[0085] refer to Figure 4 The diagram shown is a fitting illustration provided in an embodiment of this application. The first correspondence can be represented by a quadratic equation, for example, by the following formula: y = -2.1062x 2 +3.2941x - 0.3366, where x is optical power (on the x-axis) and y is image contrast ratio (SNR) (on the y-axis). This first correspondence can be stored in the device as a comparison parameter for later lookup.

[0086] If the adjusted optical power and the adjusted first interference image do not satisfy the first correspondence, it means that the adjustment of the optical power is insufficient to compensate for the quality loss of the first interference image. This is usually caused by a malfunction in the optical path that generates the first interference image in the detection system. Therefore, a first alarm message can be generated to indicate that the detection system needs to be corrected.

[0087] This application provides a control method for a detection system. A first sub-beam enters a first detection device through a first power adjustment module, and a second sub-beam enters an optical power detection module. The optical power detection module is used to detect the optical power of the incoming beams to obtain the actual optical power. In this way, the first sub-beam can illuminate the first detection device, and the second sub-beam can be used for optical power detection, thus balancing illumination and optical detection. When the actual optical power exceeds a preset range, the optical power of the beam passing through the first power adjustment module is adjusted to adjust the intensity of the first detection signal. If the intensity of the first detection signal meets a preset condition, the adjustment of the optical power of the beam passing through the first power adjustment module is stopped. In this way, the optical power can be adjusted based on the actual optical power, and the intensity of the first detection signal is used as a verification item for the optical power adjustment, so that the adjustment of the optical power can make the intensity of the first detection signal meet the preset condition, thereby achieving accurate adjustment of the optical power.

[0088] The following is a detailed description of a detection system provided in an embodiment of this application.

[0089] In this embodiment, the beam splitting module 204 may include a beam splitter, enabling the first sub-beam and the second sub-beam to exist simultaneously, allowing simultaneous illumination of the first detection device and optical power detection. Alternatively, the beam splitting module 204 can be used to switch operating modes. In the light transmission mode, the beam splitting module 204 can transmit the light beam, allowing the illumination beam to pass through the beam splitting module 204 and the first power adjustment module 207 into the first detection device 300, thus illuminating the field of view of the first detection device 300. In the reflection mode, the illumination beam is reflected by the beam splitting module 204 and enters the optical power detection module 206, allowing the optical power detection module 206 to detect the actual optical power of the incoming beam.

[0090] The first power adjustment module 207 is used to adjust the power of the beam passing through the first power adjustment module 207 when the actual optical power exceeds the preset range. In this way, the working mode can be switched by the beam splitting module 204 to realize the actual illumination and optical power detection of the illumination beam in different working modes. That is, the illumination beam is fully illuminated during the actual illumination process to ensure the illumination effect. During the interval of the actual illumination, the optical power of the full light is detected. This takes into account both full light illumination and full light detection, realizes accurate optical power detection, and thus realizes accurate adjustment of optical power. Moreover, when the working mode is switched quickly, the impact on the actual illumination of the illumination beam is small or even non-existent.

[0091] The beam splitter module 204 may include a semi-transparent, semi-reflective module. This module includes a light-transmitting path and a reflective surface. The light-transmitting path comprises a first surface and a second surface, with a transparent material between the first and second surfaces. The light-transmitting path and the reflective surface alternately switch to the propagation path of the illumination beam, thus switching the operating mode of the semi-transparent, semi-reflective module. When the light-transmitting path switches to the propagation path of the illumination beam, the corresponding operating mode is light-transmitting mode, where one of the first and second surfaces is the incident surface of the illumination beam, and the other is the exit surface. When the reflective surface switches to the propagation path of the illumination beam, the operating mode is reflection mode. The illumination beam can be intercepted outside the semi-transparent, semi-reflective module by the reflective surface, or it can pass through the module and be reflected back outside by the reflective surface. This structural arrangement of the semi-transparent, semi-reflective module allows for the switching of the operating mode of the beam splitter module 204.

[0092] The light-transmitting path and the reflective surface can alternately switch to the propagation path of the illumination beam by translation or rotation. As an example, the semi-transparent, semi-reflective module rotates at a preset rate to periodically switch the light-transmitting path and reflective surface to the propagation path of the illumination beam, achieving periodic switching of the operating mode and thus periodic detection of optical power. Rotation facilitates high-speed switching of high-speed operating modes. Specifically, the semi-transparent, semi-reflective module can be driven to rotate by a high-speed rotating motor.

[0093] In one possible implementation, the rotation axis of the semi-transparent and semi-reflective module is parallel to but not coincident with the propagation path of the illumination beam. The rotation surface of the semi-transparent and semi-reflective module can be perpendicular to or at an angle to the propagation path of the illumination beam. The semi-transparent and semi-reflective module includes a first part and a second part in the plane perpendicular to the rotation axis. The first part has a light-transmitting path, and the surface of the second part facing the illumination module 100 is a reflective surface. The angle between the reflective surface and the rotation axis is less than 90°, so that the illumination beam illuminating the reflective surface is reflected out of the original light path to the optical power detection module 206, instead of returning along the original light path. Thus, by rotating the semi-transparent and semi-reflective module around the rotation axis, the first part and the second part alternately switch to the propagation path of the illumination beam, realizing the switching of the operating mode of the semi-transparent and semi-reflective module.

[0094] The rotation axis of the semi-transparent, semi-reflective module can be located on the boundary line between the first and second parts. The semi-transparent, semi-reflective module can be circular or other shapes, and the first part is provided with an anti-reflective film. The first and second parts can each include one or multiple parts. Multiple first parts and multiple second parts are alternately arranged circumferentially on the surface of the semi-transparent, semi-reflective module facing the lighting module, allowing for multiple switching of operating modes with each rotation of the module. For example, the surface of the semi-transparent, semi-reflective module facing the lighting module may include two first parts and two second parts circumferentially, forming a grid shape. The center of the grid shape is the rotation axis of the semi-transparent, semi-reflective module. Each first part is adjacent to two second parts on both sides, and each second part is adjacent to two first parts on both sides. The first and second parts on the surface of the semi-transparent, semi-reflective module facing the lighting module can have the same area or different areas.

[0095] refer to Figure 5 and Figure 6 The diagram shown is a schematic representation of a beam splitter module according to an embodiment of this application. The beam splitter module includes a first part 204A and a second part 204B. This indicates that the surface is a transmissive surface. This indicates that the surface is a reflective surface. The dashed line shows the location of the rotation axis, which is also the boundary between the first part 204A and the second part 204B. Figure 5 The illumination beam illuminates the first part 204A, and continues to propagate forward through the beam splitter. Figure 6 The central illumination beam illuminates the second part 204B and is then reflected to the optical power detection module 206.

[0096] Specifically, the first part 204A may have parallel and opposite first and second surfaces. The reflective surface in the second part may be connected to the first surface at an obtuse angle. The second part 204B also includes a back surface connected to the second surface, and the back surface and the second surface may have the same extending direction. In the reflective surface, each point at the same distance from the rotation axis may have the same thickness, so that the illumination beam is reflected in the same direction during rotation. In this way, the optical power detection module 206 can continuously acquire the illumination beam for detection while the illumination beam continuously illuminates the second part 204B.

[0097] In another possible implementation, the rotation axis of the semi-transparent and semi-reflective module is perpendicular to the propagation direction of the illumination beam. The module has a first surface, a second surface, a third surface, and a fourth surface parallel to the rotation axis. The first and second surfaces, along with the material between them, form a light-transmitting path. The third and fourth surfaces are reflective surfaces, and the multiple surfaces constitute a multifaceted prism. The first and second surfaces can be opposite each other, allowing the illumination beam to shine from the first surface to the second surface, or vice versa. The third and fourth surfaces can also be opposite each other. The first, second, third, and fourth surfaces are sequentially switched to the propagation path of the illumination beam, thus switching the operating mode of the semi-transparent and semi-reflective module. The rotation axis of the module can be located at the center of the columnar structure formed by the first, second, third, and fourth surfaces. The rotation axis can be located in any direction within a plane perpendicular to the propagation direction of the illumination beam, for example, horizontal or vertical. Anti-reflective coatings can be provided on the first and second surfaces.

[0098] refer to Figure 7 and Figure 8 The diagram shown is a schematic representation of another beam-splitting module provided in this application embodiment. The beam-splitting module includes a first surface S3, a second surface S4, a third surface S1, and a fourth surface S2. This indicates that the surface is a transmissive surface. This indicates that the surface is a reflective surface, and the axis of rotation is perpendicular to the paper. Wherein, Figure 7 The illumination beam illuminates the first surface S3 and is transmitted to the second surface S4. The illumination beam continues to propagate forward through the beam splitter. Figure 8 The illumination beam shines on the third surface S1 and is then reflected to the optical power detection module 206.

[0099] Among them, the first surface S3 and the second surface S4 can be set in parallel. The angle between the third surface S1 and the first surface S3 is equal to the angle between the third surface S1 and the second surface S4. The third surface S1 and the fourth surface S2 are not parallel, so that the columnar structure formed by the first surface S3, the second surface S4, the third surface S1 and the fourth surface S2 is a trapezoidal columnar structure. When the third surface S1 and the fourth surface S2 switch to the propagation path of the illumination beam, during the rotation process, the reflection direction of the illumination beam reflected by the third surface S1 or the fourth surface S2 changes continuously. The duration for which the reflected beam can continuously illuminate the light power detection module 206 is related to the rotation speed of the semi-transparent and semi-reflective module.

[0100] The higher the rotation speed of the semi-transparent and semi-reflective module, the faster the switching speed of the working mode and the shorter the duration of a single working mode. With at least two working mode switches during each sampling period of the first detection device 300, each sampling corresponds to at least one transmission mode and one reflection mode. This ensures that optical power detection does not affect the normal operation of the first detection device 300, achieving a balance between optical power detection and sample detection. In other words, during the sampling interval of all-optical detection, all-optical detection is carried out without affecting sampling, macroscopically achieving simultaneous all-optical illumination and all-optical detection. Therefore, with two working mode switches per revolution of the semi-transparent and semi-reflective module (refer to...). Figure 5 and Figure 6 The rotational speed of the transflective module can be greater than or equal to the sampling frequency of the first detection device 300 per second. The sampling frequency of the first detection device 300 per second is denoted as f. Since the rotational speed v of the transflective module is greater than or equal to the sampling frequency of the first detection device 300, and the unit of the rotational speed v of the transflective module is adjusted to revolutions per minute (rpm), then v ≥ 60 * f. Taking a sampling frequency f of 54 Hz as an example, the rotational speed v ≥ 3240 rpm. This is achieved when the transflective module achieves four working mode switches per revolution (refer to...). Figure 7 and Figure 8 The number of revolutions per second of the semi-transparent and semi-reflective module can be greater than or equal to half the number of samplings per second of the first detection device (300).

[0101] A reflector 205 can be set between the beam splitter 204 and the optical power detection module 206 to reflect the light beam reflected by the beam splitter 204 back to the optical power detection module 206, causing a bend in the optical path and meeting the requirements of the intermediate visible space layout.

[0102] In this embodiment, the illumination beam can simultaneously illuminate multiple detection devices; that is, the detection system may further include a second detection device 500 and a main beam splitter 202, as shown in the reference. Figure 9 The diagram shows another detection system provided in this application embodiment. The second detection device 500 is used to detect the second surface to be tested and obtain a second detection signal. The beam splitter 202 is used to split the illumination beam into a first beam and a second beam. The first beam enters the first detection device 300 to illuminate it, and the second beam enters the second detection device 500 to illuminate it, thereby improving detection efficiency. Furthermore, a reflection module 203 may be included to bend the propagation path of the second beam.

[0103] With the master beam splitter 202 present, a first power adjustment module 207 can be positioned between the master beam splitter 202 and the illumination module 100 to adjust the total optical power of the first beam and the second beam. Furthermore, the first power adjustment module 207 can be positioned between the master beam splitter 202 and the first detection device 300 to adjust the optical power of the first beam, improving the targeted nature of the first optical power adjustment. Corresponding to the optical path of the first detection device 300, a second power adjustment module 208 can also be positioned between the second detection device 500 and the master beam splitter 202. The second power adjustment module 208 is used to adjust the optical power of the beam passing through it when the actual optical power exceeds a preset range, so that the second detection device 500 can operate under normal illumination.

[0104] The system may further include a collimating mirror 201 located between the illumination module 100 and the main beam splitter 202, used to collimate the illumination beam emitted from the illumination module 100 and improve the beam energy concentration. It may also include a first converging mirror 209 and a first optical fiber 214 between the main beam splitter 202 and the first detection device 300, and a second converging mirror 210 and a second optical fiber 213 between the main beam splitter 202 and the second detection device 300. The first converging mirror 209 and the second converging mirror 210 are used to converge the beam, and the first optical fiber 214 and the second optical fiber 213 are used to transmit the beam. The first beam enters the first optical fiber 214 through the first optical fiber receiver 212, and the second beam enters the second optical fiber 213 through the second optical fiber receiver 211. The first optical fiber 214 and the second optical fiber 213 have a homogenizing effect.

[0105] refer to Figure 9 As shown, the illumination module 100 outputs an illumination beam. After passing through the main collimating lens 201, the illumination beam becomes collimated light and is incident on the main beam splitter 202. The main beam splitter 202 splits the collimated light into a first beam and a second beam. The first beam is transmitted through the main beam splitter 202, and the second beam is reflected by the main beam splitter 202.

[0106] The first beam, after being transmitted through the main beam splitter 202, is incident on the beam splitting module 204. When the beam splitting module 204 operates in transmission mode, the first beam is incident on the first power adjustment module 207, then coupled to the first fiber receiver 212 by the first converging lens 209, and then guided to the first detection device 300 through the first fiber optic cable 214 as illumination light, illuminating one side surface of the object under test 400. When the beam splitting module 204 operates in reflection mode, the first beam passes through a reflecting surface at a certain angle to the optical path, is reflected to the reflecting mirror 205, and then reflected to the optical power detection module 206. In this way, by adding the optical power detection module 206 and the first power adjustment module 207 to the detection system, the two, through the cooperation of hardware and software control calculations, periodically detect and compensate the light output by the illumination module 100, maintaining a stable interference system. While ensuring the system illumination quality, a dynamic compensation control unit is also added to provide feedback compensation for laser attenuation, further improving the system's adaptability and measurement accuracy.

[0107] The second beam, after being reflected by the beam splitter 202, is reflected to the reflection module 203, then incident on the second power adjustment module 208, and finally coupled to the second fiber receiver 211 by the second converging lens 210. It is then guided through the second fiber optic cable 213 into the second detection device 500 as illumination light, incident on the other surface of the object under test 400. Thus, without loss of optical power, while simultaneously acquiring the double-sided interferogram of the object under test 400, the stability of the optical power of the illumination module 100 can be detected, and compensation can be made promptly through the second power adjustment module 208 if instability occurs.

[0108] The first detection device 300 can be an interferometer, such as a Fizeau interferometer. The first detection device 300 includes a first reference mirror 304, a first beam expander 303, a first beam splitter 301, and a first detector 306. The first light beam is reflected by the first beam splitter 301 and then passes through the first beam expander 303 to illuminate the first reference mirror 304. Part of the light beam passing through the first reference mirror 304 illuminates the first test surface on the side of the first reference mirror 304 away from the first beam expander 303 and is reflected to obtain a first reflected light beam. The first reflected light beam passes through the first reference mirror 304, the first beam expander 303, and the first beam splitter 301 to reach the first detector 306. Part of the light beam reflected by the first reference mirror 304 is used as a second reflected light beam. The second reflected light beam passes through the first beam expander 303 and the first beam splitter 301 to reach the first detector 306. The first detector 306 is used to acquire the interference information of the first reflected light beam and the second reflected light beam as a first detection signal.

[0109] The second detection device 500 can be an interferometer, such as a Fizeau interferometer. The second detection device 500 includes a second reference mirror 310, a second beam expander 309, a second beam splitter 307, and a second detector 312. The second beam is reflected by the second beam splitter 307 and then passes through the second beam expander 309 to illuminate the second reference mirror 310. Part of the second beam passes through the second reference mirror 310 and illuminates the second test surface on the side away from the second beam expander 309 outside the second reference mirror 310, and is then reflected to obtain a third reflected beam. The third reflected beam passes through the second reference mirror 310, the second beam expander 309, and the second beam splitter 307 to reach the second detector 312. Part of the second beam reflected by the second reference mirror 310 is used as a fourth reflected beam. The fourth reflected beam passes through the second beam expander 309 and the second beam splitter 307 to reach the second detector 312. The second detector 312 is used to obtain the interference information of the third and fourth reflected beams as a second detection signal.

[0110] The illumination beam emitted by the illumination module 100 can be linearly polarized light. The first power adjustment module 207 and the second power adjustment module 208 include polarizers. The optical power of the polarized light beam is adjusted by adjusting the polarization direction of the polarizers. Specifically, the optical power of the first beam can be adjusted by adjusting the polarization direction of the polarizer in the first power adjustment module 207, and the optical power of the second beam can be adjusted by adjusting the polarization direction of the polarizer in the second power adjustment module 208. When the first detection device 300 and the second detection device 500 are interferometers, linearly polarized light is beneficial for achieving a more obvious interference phenomenon and obtaining a high-contrast interference pattern.

[0111] The first test surface and the second test surface are surfaces on different sides of the same test object 400. The first detection device 300 may also include a first quarter-wave plate 302 between the first beam expander 303 and the first beam splitter 301, used to convert linearly polarized light into circularly polarized light. The second detection device 500 may also include a second quarter-wave plate 308 between the second beam expander 309 and the second beam splitter 307, used to convert linearly polarized light into circularly polarized light. The fast axis directions of the first quarter-wave plate 302 and the second quarter-wave plate 308 are orthogonal. The first beam splitter 301 and the second beam splitter 307 are polarizing beam splitters, enabling separate detection of the first test surface and the second test surface.

[0112] refer to Figure 9As shown, in the first detection device 300, the first light beam is reflected by the first beam splitter 301 into the first detection optical path, and then passes through the first quarter-wave plate 302 to form circularly polarized light. The circularly polarized light is expanded by the first beam expander 303, and the collimated light after expansion passes through the first reference mirror 304 and is incident on the first test surface of the object 400. The light reflected by the first test surface and the light reflected by the first reference mirror 304 interfere, enter the first beam splitter 301, is transmitted, and then passes through the first relay mirror group 305 to be imaged onto the first detector 306. Similarly, in the second detection device 500, the second light beam is reflected by the second beam splitter 307 into the second detection optical path, and then passes through the second quarter-wave plate 308 to form circularly polarized light. The circularly polarized light is expanded by the second beam expander 309, and the collimated light after expansion passes through the second reference mirror 310 and is incident on the second test surface of the object 400. The light reflected from the second test surface and the light reflected from the second reference mirror 310 interfere with each other, enter the second beam splitter 307 and are transmitted, and then pass through the second relay mirror group 311 and are imaged onto the second detector 312.

[0113] Among them, the first beam splitter 301 and the second beam splitter 307 are polarizing beam splitters, which can reflect all the incident linearly polarized s-light into the interference optical path. The fast axis directions of the first quarter-wave plate 302 and the second quarter-wave plate 308 are orthogonal, for example, the fast axis direction is + / -45° with the optical axis direction, so that the s-light passing through the first quarter-wave plate 302 and the second quarter-wave plate 308 becomes left-handed and right-handed polarized light (both circularly polarized light). The circularly polarized light reflected from the first test surface and the first reference mirror on one side of the first quarter-wave plate 302, after passing through the first quarter-wave plate 302 again, forms p-light with an orthogonal direction to the polarization direction of the s-light incident from the first beam splitter 301, and is completely transmitted from the first beam splitter into the first detector; similarly, the circularly polarized light reflected from the second test surface and the second reference mirror on one side of the second quarter-wave plate 308, after passing through the second quarter-wave plate 308 again, forms p-light with an orthogonal direction to the polarization direction of the s-light incident from the second beam splitter, and is completely transmitted from the second beam splitter into the second detector.

[0114] Conversely, the s-beam incident from the first beam splitter 301 becomes circularly polarized after passing through the first quarter-wave plate 302. It then passes through the object under test (DUT) or is incident on the opposite side of the optical path from around the DUT. After passing through the second quarter-wave plate 308, the s-beam maintains its polarization direction and is reflected out of the optical path by the second beam splitter, instead of becoming p-beam and entering the second detector. Similarly, the s-beam incident from the second beam splitter becomes circularly polarized after passing through the second quarter-wave plate 308. It then passes through the object under test (DUT) or is incident on the opposite side of the optical path from around the DUT. After passing through the first quarter-wave plate 302, the s-beam maintains its square polarization and is reflected out of the optical path by the first beam splitter, instead of becoming p-beam and entering the first detector. This prevents the two interfering optical paths from interfering with each other, enabling separate detection of the two surfaces under test.

[0115] The test object 400 can be a wafer, allowing for the inspection of both surfaces. This inspection requires high environmental and illumination stability to ensure repeatability at the nanometer level. The illumination module, a key component in interferometric pattern measurement, provides uniform illumination with well-controlled speckle for the Fizeau interferometer. The overall brightness and uniformity of the interferogram formed by the interference between the reference mirror and the surface of the wafer under test significantly affect the contrast of the interference fringes. Therefore, adding a stable and reliable monitoring unit to the illumination optical path is crucial.

[0116] The detection system provided in this application embodiment may include an illumination module and a first detection device, as well as a beam splitting module and a first power adjustment module between the illumination module and the first detection device. The beam splitting module is used to periodically switch working modes. When the working mode is the light transmission mode, the illumination beam passes through the beam splitting module and the first power adjustment module to enter the first detection device. When the working mode is the reflection mode, the illumination beam is reflected by the beam splitting module and enters the optical power detection module. The optical power detection module is used to detect the optical power of the incoming beam to obtain the actual optical power. The first power adjustment module is used to adjust the power of the beam passing through the first power adjustment module when the actual optical power exceeds a preset range. In this way, the actual illumination and optical power detection of the illumination beam can be realized in different working modes by switching the working mode through the beam splitting module. That is, the illumination beam is fully illuminated during the actual illumination process to ensure the illumination effect. Full-light optical power detection is performed during the interval of the actual illumination of the illumination beam to achieve accurate optical power detection and thus accurate adjustment of optical power. Moreover, when the working mode is switched rapidly, the actual illumination of the illumination beam is minimally affected or even negligible.

[0117] Based on the detection system provided in the above embodiments, the aforementioned control method can be further refined.

[0118] Specifically, for linearly polarized light illuminating the beam, the first power adjustment module includes a polarizer. In step S101, when the actual optical power exceeds a preset range, the polarization direction of the polarizer can be adjusted to adjust the optical power of the beam passing through the first power adjustment module. In practice, when the actual optical power exceeds the preset range, the required polarization direction of the polarizer can be determined based on the required optical power. Based on the required polarization direction, the polarization direction of the polarizer is adjusted to increase the optical power of the beam passing through the first power adjustment module. This method achieves accurate control of the optical power. Since the angle between the polarization direction of the incident linearly polarized light and the polarization direction of the polarizer differs, the transmission ratio of the linearly polarized light also differs. Therefore, the angle between the polarization direction of the incident linearly polarized light and the polarization direction of the polarizer can be determined based on the actual optical power and the required optical power, thereby determining the required polarization direction of the polarizer and achieving power adjustment.

[0119] When the required optical power remains constant, there is a corresponding relationship between the required polarization direction and the actual optical power. Therefore, after the actual optical power attenuates, the required polarization direction can be determined based on this relationship, and the polarizer can be adjusted to compensate for the lost optical power. In other words, during actual operation, the polarization direction of the polarizer is usually not parallel to the polarization direction of the illumination beam to allow for a compensation range for subsequent compensation. During the equipment debugging phase, the correspondence between different required polarization directions and different actual optical powers can be saved and stored in the equipment for later retrieval.

[0120] In this embodiment, when the detection system includes a second power adjustment module, in S102, if the actual optical power exceeds a preset range, the optical power of the beam passing through the second power adjustment module can be adjusted to adjust the intensity of the second detection signal. Furthermore, if the intensity of the second detection signal meets a preset condition, it indicates that the quality of the second detection signal is high. Therefore, the adjustment of the optical power of the beam passing through the second power adjustment module can be stopped. This allows for optical power adjustment based on the actual optical power, using the intensity of the second detection signal as a verification item for optical power adjustment, ensuring that the optical power adjustment enables the intensity of the second detection signal to meet the preset condition, thus achieving accurate optical power adjustment.

[0121] Specifically, when the actual optical power is less than the lower limit of a preset range, the optical power of the beam passing through the second power adjustment module is increased. In practice, when the actual optical power is less than the lower limit of the preset range, the required optical power of the second beam is determined based on the lower limit of the preset range; the optical power of the beam passing through the second power adjustment module is increased based on the required optical power of the second beam, thereby increasing the optical power of the second beam, improving the signal quality of the second detection signal, and enhancing detection accuracy.

[0122] In specific implementation, the illumination beam is linearly polarized. The second power adjustment module includes a polarizer. When the actual optical power exceeds a preset range, the polarization direction of the polarizer is adjusted to adjust the optical power of the beam transmitted through the second power adjustment module. Specifically, when the actual optical power exceeds the preset range, the required polarization direction of the polarizer can be determined based on the required optical power of the second beam. Based on the required polarization direction, the polarization direction of the polarizer is adjusted to increase the optical power of the beam transmitted through the second power adjustment module. This method achieves accurate control of optical power. Different angles between the polarization direction of the incident linearly polarized light and the polarization direction of the polarizer result in different transmission ratios of the linearly polarized light. Therefore, the angle between the polarization direction of the incident linearly polarized light and the polarization direction of the polarizer can be determined based on the actual optical power and the required optical power, thereby determining the required polarization direction of the polarizer and achieving power adjustment.

[0123] When the required optical power remains constant, the required polarization direction corresponds to the actual optical power. Therefore, after the actual optical power attenuates, the required polarization direction can be determined based on this correspondence, and the polarizer can be adjusted to compensate for the lost optical power. In other words, during actual operation, the polarization direction of the polarizer is usually not parallel to the polarization direction of the illumination beam to allow for a compensation range for subsequent compensation. During equipment debugging, the correspondence between different required polarization directions and different actual optical powers can be saved and stored in the equipment for later retrieval.

[0124] When the second detection signal includes the second interferometric image, if the contrast ratio (SNR) of the second interferometric image is within a preset contrast range, it indicates that the second interferometric image can accurately reflect the characteristics of the interference fringes. Therefore, the intensity of the second detection signal can be considered to meet the preset conditions, and the adjustment of the optical power of the beam transmitted through the second optical power adjustment module can be stopped. Using the contrast ratio of the second interferometric image as a verification item helps to obtain a higher quality second interferometric image and improve detection accuracy. The contrast ratio of the second interferometric image can be the contrast ratio within a fixed region of the second interferometric image, and this contrast ratio within the fixed region represents the overall contrast ratio of the second interferometric image.

[0125] When the second detection signal includes the second interference image, the actual optical power and the contrast of the second interference image can also be fitted to obtain a second correspondence between optical power and image contrast. If the adjusted actual optical power and the adjusted second interference image satisfy the second correspondence, and the contrast of the second interference image is within the preset contrast range, it indicates that the second interference image can accurately reflect the characteristics of the interference fringes, and the correspondence between the actual optical power and the contrast of the second interference image is maintained. The detection system is functioning normally, and the intensity of the second detection signal can be considered to meet the preset conditions. The adjustment of the optical power of the beam passing through the second optical power adjustment module can be stopped. Using the contrast of the second interference image and the second correspondence as verification items is beneficial to obtaining a high-quality second interference image. At the same time, the function of the detection system can be verified, and the detection accuracy can be improved.

[0126] The second correspondence can be expressed by a quadratic equation, for example, by the following formula: y = -2.1062x 2 +3.2941x-0.3366, where x is the optical power, used as the horizontal axis, and y is the image contrast ratio (SNR), used as the vertical axis.

[0127] If the adjusted optical power and the adjusted second interference image do not satisfy the second correspondence, it means that the adjustment of the optical power is insufficient to compensate for the quality loss of the second interference image. This is usually caused by a malfunction in the optical path that generates the second interference image in the detection system. Therefore, a second alarm message can be generated to indicate that the detection system needs to be corrected.

[0128] Those skilled in the art will understand that all or part of the steps of the above method embodiments can be implemented by program instructions in hardware. The aforementioned program can be stored in a computer-readable storage medium. When the program is executed, it performs the steps of the above method embodiments. The aforementioned storage medium can be at least one of the following media: read-only memory (ROM), RAM, magnetic disk, or optical disk, etc., and other media capable of storing program code.

[0129] The above description is merely a preferred embodiment of this application. Although this application has disclosed preferred embodiments above, it is not intended to limit this application. Any person skilled in the art can make many possible variations and modifications to the technical solutions of this application using the methods and techniques disclosed above, or modify them into equivalent embodiments with equivalent changes, without departing from the scope of the technical solutions of this application. Therefore, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of this application without departing from the content of the technical solutions of this application shall still fall within the protection scope of the technical solutions of this application.

Claims

1. A control method of a detection system, characterized by, The detection system comprises an illumination module, a first detection device, and a light splitting module and a first power adjustment module between the illumination module and the first detection device, the illumination module is configured to provide an illumination light beam, the first detection device is configured to detect a first surface to be detected to obtain a first detection signal, the light splitting module is configured to split the illumination light beam to obtain a first sub-light beam and a second sub-light beam, the first sub-light beam passes through the first power adjustment module and enters the first detection device, and the second sub-light beam enters a light power detection module. The light power detection module is configured to detect the light power of the entering light beam to obtain an actual light power. The method comprises: When the actual light power exceeds a preset range, the light power of the light beam passing through the first power adjustment module is adjusted to adjust the intensity of the first detection signal. If the intensity of the first detection signal meets a preset condition, the adjustment of the light power of the light beam passing through the first power adjustment module is stopped; the first detection signal comprises a first interference image, and the preset condition comprises that the contrast of the first interference image is within a preset contrast range.

2. The method of claim 1, wherein, When the actual light power exceeds a preset range, the light power of the light beam passing through the first power adjustment module is adjusted to adjust the intensity of the first detection signal. When the actual light power is less than the lower limit of the preset range, the required light power is determined according to the lower limit of the preset range. The light power of the light beam passing through the first power adjustment module is increased according to the required light power.

3. The method of claim 2, wherein, The illumination light beam is linearly polarized light, and the first power adjustment module comprises a polarizer. The required polarization direction of the polarizer is determined according to the required light power. The polarization direction of the polarizer is adjusted according to the required polarization direction to increase the light power of the light beam passing through the first power adjustment module.

4. The method of claim 1, wherein, The method further comprises: A first correspondence relationship between light power and image contrast is obtained by fitting the actual light power and the contrast of the first interference image. The preset condition is specifically that the adjusted actual light power and the adjusted first interference image meet the first correspondence relationship, and the contrast of the first interference image is within a preset contrast range.

5. The method of claim 4, wherein, The method further comprises: If the adjusted light power and the adjusted first interference image do not meet the first correspondence relationship, first alarm information is generated.

6. The method of claim 4, wherein, The first correspondence relationship is represented by the following formula: y = -2.1062x 2 + 3.2941x - 0.3366, x is the light power, and y is the image contrast.

7. The method according to any one of claims 1 to 6, characterized in that, The light splitting module is configured to switch between a transmission mode and a reflection mode, when the light splitting module is in the transmission mode, the illumination light beam passes through the light splitting module to obtain a first sub-light beam, the first sub-light beam passes through the first power adjustment module and enters the detection device, and when the light splitting module is in the reflection mode, the illumination light beam is reflected by the light splitting module to obtain a second sub-light beam, the second sub-light beam enters the light power detection module.

8. The method of claim 7, wherein, The light splitting module comprises a semi-transparent and semi-reflective module, the semi-transparent and semi-reflective module comprises a light transmission path and a reflecting surface, the light transmission path comprises a first surface and a second surface, the material between the first surface and the second surface is transparent, and the light transmission path and the reflecting surface are alternately switched to the propagation path of the illumination light beam, so that the semi-transparent and semi-reflective module switches the working mode. When the light transmission path is switched to the propagation path of the illumination light beam, the working mode is a light transmission mode; when the reflecting surface is switched to the propagation path of the illumination light beam, the working mode is a reflection mode.

9. The method of claim 8, wherein, The semi-transparent and semi-reflective module rotates at a preset speed to periodically switch the light transmission path and the reflecting surface to the propagation path of the illumination light beam.

10. The method of claim 8, wherein, The rotation axis of the semi-transparent and semi-reflective module is parallel to and does not coincide with the propagation path of the illumination light beam, the semi-transparent and semi-reflective module comprises a first part and a second part in a plane perpendicular to the rotation axis, the first part has a light transmission path, and the second part has a reflecting surface on the side surface of the illumination module, the angle between the reflecting surface and the rotation axis is less than 90°; when the semi-transparent and semi-reflective module rotates around the rotation axis, the first part and the second part are alternately switched to the propagation path of the illumination light beam.

11. The method of claim 8, wherein, The rotation axis of the semi-transparent and semi-reflective module is perpendicular to the propagation direction of the illumination light beam, the semi-transparent and semi-reflective module has the first surface, the second surface, a third surface and a fourth surface which are parallel to the rotation axis; the first surface and the second surface are opposite surfaces; the third surface and the fourth surface are opposite surfaces and are reflecting surfaces.

12. The method of claim 8, wherein, The rotation speed of the semi-transparent and semi-reflective module corresponds to at least one light transmission mode and one reflection mode in a single sampling of the first detection device.

13. The method according to any one of claims 1 to 6, characterized in that, The detection system further comprises: A second detection device for detecting a second to-be-detected surface to obtain a second detection signal; A total light splitting mirror for splitting the illumination light beam into a first light beam and a second light beam, the first light beam entering the first detection device, and the second light beam entering the second detection device; A second power adjustment module between the total light splitting mirror and the second detection device; The method further comprises: When the actual optical power exceeds a preset range, adjusting the optical power of the light beam passing through the second power adjustment module to adjust the intensity of the second detection signal; If the intensity of the second detection signal meets a preset condition, stop adjusting the optical power of the light beam passing through the second power adjustment module.

14. The method of claim 13, wherein, The second detection signal comprises a second interference image, and if the intensity of the second detection signal meets a preset condition, stop adjusting the optical power of the light beam passing through the second power adjustment module, which comprises: If the contrast of the second interference image is within a preset contrast range, stop adjusting the optical power of the light beam passing through the second power adjustment module.

15. The method of claim 13, wherein, The second detection signal comprises a second interference image, and the method further comprises: Fitting the actual optical power and the contrast of the second interference image to obtain a second correspondence between optical power and image contrast; If the intensity of the second detection signal meets a preset condition, the adjustment of the optical power of the light beam transmitted through the second power adjustment module is stopped, including: If the adjusted actual optical power and the adjusted second interference image meet the second correspondence relationship, and the contrast of the second interference image is in a preset contrast range, the adjustment of the optical power of the light beam transmitted through the second power adjustment module is stopped.

16. The method of claim 15, wherein, The method further includes: If the adjusted optical power and the adjusted second interference image do not meet the second correspondence relationship, second alarm information is generated.

17. The method of claim 13, wherein, The first detection device includes a first reference mirror, a first beam expander, a first beam splitter, and a first detector. The first light beam is reflected by the first beam splitter and transmitted through the first beam expander to illuminate the first reference mirror. Part of the light transmitted through the first reference mirror is reflected to the first surface on the side of the first reference mirror away from the first beam expander to obtain a first reflected light beam. The first reflected light beam passes through the first reference mirror, the first beam expander, and the first beam splitter to reach the first detector. Part of the light reflected by the first reference mirror is a second reflected light beam. The second reflected light beam passes through the first beam expander and the first beam splitter to reach the first detector. The first detector acquires interference information of the first reflected light beam and the second reflected light beam as the first detection signal; and / or The second detection device includes a second reference mirror, a second beam expander, a second beam splitter, and a second detector. The second light beam is reflected by the second beam splitter and transmitted through the second beam expander to illuminate the second reference mirror. Part of the light transmitted through the second reference mirror is reflected to the second surface on the side of the second reference mirror away from the second beam expander to obtain a third reflected light beam. The third reflected light beam passes through the second reference mirror, the second beam expander, and the second beam splitter to reach the second detector. Part of the light reflected by the second reference mirror is a fourth reflected light beam. The fourth reflected light beam passes through the second beam expander and the second beam splitter to reach the second detector. The second detector acquires interference information of the third reflected light beam and the fourth reflected light beam as the second detection signal.

18. The method of claim 17, wherein, If the illumination light beam is linearly polarized light, the first surface and the second surface are surfaces of different sides of the same measured object. The first detection device further includes a first quarter-wave plate between the first beam expander and the first beam splitter. The second detection device further includes a second quarter-wave plate between the second beam expander and the second beam splitter. The fast axis directions of the first quarter-wave plate and the second quarter-wave plate are orthogonal. The first beam splitter and the second beam splitter are polarization beam splitters.

19. The method of claim 13, wherein, The detection system further includes: A total collimating mirror between the illumination module and the total beam splitter; A first focusing mirror and a first optical fiber between the total beam splitter and the first detection device; A second focusing lens and a second optical fiber between the total spectroscope and the second detection device.

20. The method of any one of claims 1-6, wherein, The detection system further comprises: A mirror between the light splitting module and the optical power detection module, for reflecting the light beam reflected by the light splitting module to the optical power detection module.

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