Detection system and optical power adjustment method

Abstract

The invention provides a detection system and an optical power adjustment method, the detection system may comprise 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 light splitting module is used for periodically switching a working mode, and when the working mode is a light transmission mode, the first power adjustment module is used for adjusting the light power. When the working mode is the light splitting module, the illumination beam enters the first detection device through the light splitting module and the first power adjustment module, when the working mode is the reflection mode, the illumination beam enters the optical power detection module through reflection of the light splitting module, and the optical power detection module is used for detecting the optical power of the entered beam to obtain the actual optical power. The first power adjusting module is used for adjusting the power of the light beam penetrating through the first power adjusting module when the actual light power exceeds a preset range, the illumination light beam is subjected to full-light illumination in the actual illumination process, the illumination effect is guaranteed, and full-light light power detection is carried out at the gap of actual illumination of the illumination light beam. And accurate optical power detection and adjustment are realized.

Description

Technical Field

[0001] The present application relates to the field of microscopic imaging, and in particular to a detection system and an optical power adjustment method. Background Art

[0002] Currently, the surface to be tested can be tested through testing equipment. During the testing process, the lighting module is required to provide a lighting beam. High-precision testing equipment requires higher environmental stability and lighting stability. In actual operation, if the intensity of the lighting beam changes, it is easy to cause inaccurate test results and reduced detection accuracy, affecting the stability of the testing equipment and the measurement accuracy.

[0003] In the current detection method of the intensity of the lighting beam, a spectrometer module is usually used to divide the lighting beam into two parts. One part enters the detection device for lighting, and the other part enters the light intensity detection device for light detection. In this way, light detection and detection device lighting can be carried out at the same time. However, after the lighting beam is split, the light intensity is reduced, which affects the lighting effect of the detection device. Summary of the invention

[0004] In view of this, the purpose of the present application is to provide a detection system and an optical power adjustment method to achieve full-light illumination and full-light intensity detection, ensure the lighting stability in the detection system, and ensure the stability of the system and the measurement accuracy.

[0005] The specific plan is as follows:

[0006] In one aspect, the present application provides a detection system, comprising:

[0007] A lighting module, used for providing a lighting beam;

[0008] A first detection device, used for detecting a first surface to be detected to obtain a first detection signal;

[0009] A spectroscopic module and a first power adjustment module are provided between the lighting module and the first detection device, wherein the spectroscopic module is used to periodically switch the working mode. When the working mode is the light transmission mode, the lighting light beam passes through the spectroscopic module and the first power adjustment module to enter the first detection device. When the working mode is the reflection mode, the lighting light beam enters the optical power detection module after being reflected by the spectroscopic module. The optical power detection module is used to perform optical power detection on the incoming light beam to obtain the actual optical power. The first power adjustment module is used to adjust the optical power of the light beam passing through the first power adjustment module when the actual optical power exceeds a preset range.

[0010] Optionally, the light splitting module includes a semi-transparent and semi-reflective module, the semi-transparent and semi-reflective module includes a light-transmitting path and a reflective surface, the light-transmitting path includes a first surface and a second surface, the material between the first surface and the second surface is a transparent material, the light-transmitting path and the reflective surface are periodically switched to the propagation path of the illumination light beam, so that the semi-transparent and semi-reflective module periodically switches the working mode;

[0011] When the light-transmitting passage is switched to the propagation path of the illumination light beam, the working mode is the light-transmitting mode; when the reflective surface is switched to the propagation path of the illumination light beam, the working mode is the reflective mode.

[0012] Optionally, the semi-transmissive and semi-reflective module rotates at a preset rate so that the light-transmitting passage and the reflective surface are periodically switched to the propagation path of the illumination light beam.

[0013] Optionally, the rotation axis of the semi-transparent and semi-reflective module is parallel to and does not overlap with the propagation path of the illumination light beam, and 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 passage, and the surface of the second part facing the illumination module is a reflective surface, and 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 light beam.

[0014] Optionally, the rotation axis of the semi-transparent and semi-reflective module is perpendicular to the propagation direction of the illumination light beam, and the semi-transparent and semi-reflective module has the first surface, the second surface, the third surface and the 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.

[0015] Optionally, the first surface and the second surface are arranged in parallel, the angle between the third surface and the first surface is equal to the angle between the third surface and the second surface, and the third surface and the fourth surface are not parallel.

[0016] Optionally, the rotation speed of the semi-transmissive and semi-reflective module enables a single sampling of the first detection device to correspond to at least one light transmission mode and one reflection mode.

[0017] Optionally, the system further includes:

[0018] A second detection device, used for detecting a second surface to be detected to obtain a second detection signal;

[0019] The total beam splitter is used to split the illumination light beam into a first light beam and a second light beam, wherein the first light beam enters the first detection device and the second light beam enters the second detection device.

[0020] 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 irradiated to the first reference mirror through the first beam expander, part of the light of the first light beam transmitted through the first reference mirror is irradiated to a first surface to be measured outside the first reference mirror away from the first beam expander and then 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, part of the light of the first light beam reflected by the first reference mirror is used 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 obtain interference information of the first reflected light beam and the second reflected light beam as the first detection signal; and / or,

[0021] 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 then irradiated to the second reference mirror through the second beam expander. Part of the light of the second light beam that passes through the second reference mirror is irradiated to a second surface to be measured outside the second reference mirror and away from the second beam expander, and then is reflected 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 of the second light beam reflected by the second reference mirror is used as 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 is used to obtain interference information of the third reflected light beam and the fourth reflected light beam as the second detection signal.

[0022] Optionally, the system further includes:

[0023] A second power adjustment module is provided between the total spectroscope and the second detection device, wherein the second power adjustment module is used to adjust the optical power of the light beam passing through the second power adjustment module when the actual optical power exceeds a preset range.

[0024] Optionally, the illumination light beam is linearly polarized light, and the first power adjustment module and the second power adjustment module include polarizers, and the optical power of the light beam passing through the polarizers is adjusted by adjusting the polarization direction of the polarizers.

[0025] Optionally, the first surface to be measured and the second surface to be measured are surfaces on different sides of the same object to be measured, the first detection device also includes a first quarter-wave plate between the first beam expander and the first beam splitter, the second detection device also 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 directions, and the first beam splitter and the second beam splitter are polarization beam splitters.

[0026] Optionally, the system further includes:

[0027] A total collimator located between the lighting module and the total beam splitter;

[0028] a first converging mirror and a first optical fiber between the total spectroscope and the first detection device;

[0029] A second converging mirror and a second optical fiber between the total beam splitter and the second detection device.

[0030] Optionally, the system further includes:

[0031] The reflector between the light splitting module and the optical power detection module is used to reflect the light beam reflected by the light splitting module to the optical power detection module.

[0032] On the other hand, the embodiment of the present application further provides an optical power adjustment method, which is applied to the detection system, and the method includes:

[0033] 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.

[0034] Optionally, when the actual optical power exceeds a preset range, adjusting the optical power of the light beam passing through the first power adjustment module includes:

[0035] When the actual optical power is less than a lower limit of a preset range, the optical power of the light beam passing through the first power adjustment module is increased.

[0036] Optionally, the illumination light beam is linearly polarized, and the first power adjustment module includes a polarizer. 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, including:

[0037] When the actual optical power exceeds a preset range, the polarization direction of the polarizer is adjusted to adjust the optical power of the light beam passing through the first power adjustment module.

[0038] The embodiment of the present application provides a detection system and an optical power adjustment method. The detection system may include an illumination module and a first detection device, and a spectroscopic module and a first power adjustment module between the illumination module and the first detection device. The spectroscopic module is used to periodically switch the working mode. When the working mode is the light transmission mode, the illumination light beam passes through the spectroscopic module and the first power adjustment module to enter the first detection device. When the working mode is the reflection mode, the illumination light beam enters the optical power detection module after being reflected by the spectroscopic module. The optical power detection module is used to perform optical power detection on the entering light beam to obtain the actual optical power. The first power adjustment module is used to adjust the power of the light beam passing through the first power adjustment module when the actual optical power exceeds a preset range. In this way, the working mode can be switched by the spectroscopic module to respectively realize the actual illumination and optical power detection of the illumination light beam in different working modes, that is, the illumination light beam passes through full light illumination during the actual illumination process to ensure the illumination effect, and full light optical power detection is performed in the gap between the actual illumination of the illumination light beam to realize accurate optical power detection and then realize accurate adjustment of the optical power. In addition, when the working mode is switched quickly, the actual illumination of the illumination light beam is less affected or even has no effect. It is possible to realize optical power detection without affecting the detection of the surface to be detected by the detection device. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0040] Figure 1 A schematic diagram of the structure of a detection system provided in an embodiment of the present application is shown;

[0041] Figure 2 and Figure 3 A schematic diagram of the operation of a light splitting module provided in an embodiment of the present application;

[0042] Figure 4 and Figure 5 A schematic diagram of another light splitting module provided in an embodiment of the present application;

[0043] Figure 6 A schematic diagram of the structure of another detection system provided in an embodiment of the present application is shown;

[0044] Figure 7 A schematic diagram of a first interference image provided in an embodiment of the present application. DETAILED DESCRIPTION

[0045] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below with reference to the accompanying drawings.

[0046] In the following description, many specific details are set forth to facilitate a full understanding of the present application, but the present application may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present application. Therefore, the present application is not limited to the specific embodiments disclosed below.

[0047] Secondly, the present application is described in detail with reference to the schematic diagram. When describing the embodiments of the present application in detail, for the sake of convenience, the cross-sectional diagrams showing the device structure will not be partially enlarged according to the general scale, and the schematic diagrams are only examples, which should not limit the scope of protection of the present application. In addition, in actual production, the three-dimensional dimensions of length, width and depth should be included.

[0048] To facilitate understanding, a detection system and an optical power adjustment method provided in an embodiment of the present application are described in detail below with reference to the accompanying drawings.

[0049] refer to Figure 1 As shown, it is a structural schematic diagram of a detection system provided in an embodiment of the present application, and the detection system includes a lighting module 100, a first detection device 300, and a spectrometer module 204 and a first power adjustment module 207 between the lighting module 100 and the first detection device 300.

[0050] The lighting module 100 is used to provide an illumination beam, so as 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 composite light of multiple wavelengths. If the first detection device 300 is other instruments, the illumination beam may be composite light of multiple wavelengths.

[0051] The first detection device 300 is used to detect the first surface to be detected to obtain a first detection signal. The first detection device 300 can be an interferometer or other detection devices. When the detection accuracy of the first detection device 300 is high, the lighting module 100 is required to provide a stable lighting beam, for example, the optical power of the lighting beam entering the first detection device 300 needs to be within a preset range.

[0052] The spectroscopic module 204 is used to periodically switch the working mode, and the optical power detection module 206 is used to detect the optical power of the incoming light beam to obtain the actual optical power. When the working mode is the light transmission mode, the spectroscopic module 204 can transmit the light beam, and the illumination light beam passes through the spectroscopic module 204 and the first power adjustment module 207 to enter the first detection device 300, that is, the illumination light beam illuminates the field of view of the first detection device 300. When the working mode is the reflection mode, the illumination light beam enters the optical power detection module 206 after being reflected by the spectroscopic module 204, so that the optical power detection module 206 detects the optical power of the incoming light beam to obtain the actual optical power.

[0053] The first power adjustment module 207 is used to adjust the power of the light beam passing through the first power adjustment module 207 when the actual light power exceeds a preset range, so that the working mode can be switched by the spectroscopic module 204 to respectively realize the actual lighting and light power detection of the illumination light beam in different working modes, that is, the illumination light beam passes through full-light illumination during the actual lighting process to ensure the lighting effect, and performs full-light light power detection in the intervals when the illumination light beam performs actual lighting, taking into account both full-light illumination and full-light detection, to realize accurate light power detection and then realize accurate adjustment of light power, and when the working mode is switched quickly, the actual lighting of the illumination light beam is less affected or even has no effect, so that light power detection can be performed without affecting the detection of the surface to be tested by the detection equipment.

[0054] The light splitting module 204 may include a semi-transparent and semi-reflective module, which includes a light-transmitting path and a reflective surface. The light-transmitting path includes a first surface and a second surface. The material between the first surface and the second surface is a transparent material. The light-transmitting path and the reflective surface periodically switch to the propagation path of the illumination light beam, so that the semi-transparent and semi-reflective module periodically switches the working mode. When the light-transmitting path switches to the propagation path of the illumination light beam, the corresponding working mode is the light-transmitting mode, one of the first surface and the second surface is the incident surface of the illumination light beam, and the other is the exit surface of the illumination light beam; when the reflective surface switches to the propagation path of the illumination light beam, the working mode is the reflective mode, and the illumination light beam can be intercepted outside the semi-transparent and semi-reflective module through the reflective surface, or can be reflected outside the semi-transparent and semi-reflective module by the reflective surface through the semi-transparent and semi-reflective module. In this way, the working mode switching of the light splitting module 204 can be realized by setting the structure of the semi-transparent and semi-reflective module.

[0055] The light-transmitting path and the reflective surface can be switched alternately to the propagation path of the illumination beam by translation, or can be switched alternately to the propagation path of the illumination beam by rotation. As an example, the semi-transmitting and semi-reflecting module rotates at a preset rate so that the light-transmitting path and the reflective surface are periodically switched to the propagation path of the illumination beam, thereby realizing the periodic switching of the working mode and further realizing the periodic detection of the optical power. The rotation method is conducive to realizing the high-speed switching of the high-speed working mode. Specifically, the semi-transmitting and semi-reflecting module can be driven to rotate by a high-speed rotating motor.

[0056] As a possible implementation, the rotation axis of the semi-transparent and semi-reflective module is parallel to and does not overlap with the propagation path of the illumination light beam, and the rotation plane of the semi-transparent and semi-reflective module can be perpendicular to or at a certain angle to the propagation path of the illumination light 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 passage, and the second part has a reflective surface on one side facing the illumination module 100, and the angle between the reflective surface and the rotation axis is less than 90°, so as to reflect the illumination light beam irradiated on the reflective surface out of the original light path to the optical power detection module 206, instead of returning along the original light path. In this way, by rotating the semi-transparent and semi-reflective module around the rotation axis, the first part and the second part are alternately switched to the propagation path of the illumination light beam, thereby realizing the switching of the working mode of the semi-transparent and semi-reflective module.

[0057] Among them, the rotation axis of the semi-transparent and semi-reflective module can be located on the boundary line of the first part and the second part. The semi-transparent and semi-reflective module can be circular or in other shapes, and the first part is provided with an anti-reflection film. The first part and the second part can each include one or more, and the multiple first parts and the multiple second parts are alternately arranged along the circumferential direction on the side surface of the semi-transparent and semi-reflective module facing the lighting module, so that the semi-transparent and semi-reflective module can achieve multiple switching of working modes by rotating one circle. For example, the side surface of the semi-transparent and semi-reflective module facing the lighting module includes two first parts and two second parts in the circumferential direction, forming a field shape, and the center of the field shape is the rotation axis of the semi-transparent and semi-reflective module. The two sides of a first part are respectively adjacent to the two second parts, and the two sides of a second part are respectively adjacent to the two first parts. The first part and the second part can have the same area or different areas on the side surface of the semi-transparent and semi-reflective module facing the lighting module.

[0058] refer to Figure 2 and Figure 3 FIG. 2 is a schematic diagram of a working state of a light splitting module provided in an embodiment of the present application. The light splitting module includes a first part 204A and a second part 204B. Indicates that the surface is a transmissive surface. Indicates that the surface is a reflective surface, and the dotted line indicates the location of the rotation axis, which is also the boundary between the first part 204A and the second part 204B. Figure 2The illumination beam irradiates the first portion 204A, and the illumination beam continues to propagate forward through the light splitting module. Figure 3 The middle illumination light beam irradiates the second portion 204B and is then reflected to the optical power detection module 206 .

[0059] Specifically, the first part 204A may have a first surface and a second surface that are parallel and opposite to each other, the reflective surface in the second part may be connected to the first surface and form an obtuse angle, and 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 extension direction. In the reflective surface, each point that has the same distance from the rotation axis may have the same thickness, so that the illumination beam reflects the illumination beam to the same direction during the rotation process, so that the optical power detection module 206 can continuously obtain the illumination beam when the illumination beam continues to irradiate the second part 204B for detection.

[0060] As another possible implementation, 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 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 and the material therebetween constitute a light transmission path. The third surface and the fourth surface are reflective surfaces. The multiple surfaces constitute a multi-faceted prism. The first surface and the second surface can be opposite surfaces, so that the illumination light beam is irradiated from the first surface to the second surface, or from the second surface to the first surface; the third surface and the fourth surface can be opposite surfaces. The first surface, the second surface, the third surface and the fourth surface are switched to the propagation path of the illumination light beam in a certain order, so as to realize the switching of the working mode of the semi-transparent and semi-reflective module. Among them, the rotation axis of the semi-transparent and semi-reflective module can be located at the center of the columnar structure formed by the first surface, the second surface, the third surface and the fourth surface, and the rotation axis can be located in any direction in a plane perpendicular to the propagation direction of the illumination light beam, for example, it can be a horizontal direction or a vertical direction. The first surface and the second surface can be provided with an anti-reflection film.

[0061] refer to Figure 4 and Figure 5 FIG. 1 is a schematic diagram of another light splitting module provided in an embodiment of the present application. The light splitting module includes a first surface S3, a second surface S4, a third surface S1 and a fourth surface S2. Indicates that the surface is a transmissive surface. Indicates that the surface is a reflective surface, and the rotation axis is perpendicular to the paper. Figure 4 The illumination beam irradiates the first surface S3 and transmits to the second surface S4. The illumination beam continues to propagate forward through the light splitting module. Figure 5 The middle illumination light beam irradiates the third surface S1 and is then reflected to the optical power detection module 206 .

[0062] Among them, the first surface S3 and the second surface S4 can be arranged 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, and 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 are switched to the propagation path of the illumination light beam, during the rotation process, the reflection direction of the illumination light beam reflected by the third surface S1 or the fourth surface S2 changes continuously, and the length of time that the reflected light beam can continuously illuminate the optical power detection module 206 is related to the rotation speed of the semi-transparent and semi-reflective module.

[0063] The greater the number of revolutions per second 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. During each sampling period of the first detection device 300, the working mode is switched at least twice, and each sampling corresponds to at least one light transmission mode and one reflection mode, so that the optical power detection does not affect the normal operation of the first detection device 300, and the optical power detection and sample detection are taken into account. That is, in the sampling interval of full-light detection, full-light detection is taken into account without affecting sampling, and full-light illumination and full-light detection are carried out simultaneously from a macroscopic perspective. Then, when the semi-transparent and semi-reflective module rotates one circle to achieve two working mode switchings (refer to Figure 2 and Figure 3 ), the number of revolutions of the semi-transparent and semi-reflective module per second may be greater than or equal to the number of samplings of the first detection device 300 per second, the number of samplings of the first detection device 300 per second is recorded as the sampling frequency f, the number of revolutions of the semi-transparent and semi-reflective module per second is greater than or equal to the sampling frequency of the first detection device 300, the unit of the rotation speed v of the semi-transparent and semi-reflective module is adjusted to revolutions per minute (rpm), then v≥60*f, taking the sampling frequency f as 54Hz as an example, the rotation speed v≥3240rpm; in the case where the semi-transparent and semi-reflective module rotates one circle to achieve four working mode switchings (reference Figure 4 and Figure 5 ), the number of rotations of the semi-transparent and semi-reflective module per second can be greater than or equal to half of the number of sampling times of the first detection device 300 per second.

[0064] A reflector 205 may be provided between the light splitting module 204 and the optical power detection module 206 to reflect the light beam reflected by the light splitting module 204 to the optical power detection module 206, so that the light path has a turn to meet the requirements of the intermediate visible space layout.

[0065] In the embodiment of the present application, the illumination beam can provide illumination to multiple detection devices at the same time, that is, the detection system can also include a second detection device 500 and a total spectroscope 202, referring to Figure 6As shown, it is a structural schematic diagram of another detection system provided by an embodiment of the present application, the second detection device 500 is used to detect the second surface to be detected to obtain a second detection signal, the total beam splitter 202 is used to divide the illumination light beam into a first light beam and a second light beam, the first light beam enters the first detection device 300, and is used to illuminate the first detection device 300, and the second light beam enters the second detection device 500, and is used to illuminate the second detection device 500, thereby improving the detection efficiency. In addition, a reflection module 203 can also be included to bend the propagation path of the second light beam.

[0066] In the presence of the total spectroscope 202, the first power adjustment module 207 can be arranged between the total spectroscope 202 and the lighting module 100 to adjust the total optical power of the first light beam and the second light beam. In addition, the first power adjustment module 207 can be arranged between the total spectroscope 202 and the first detection device 300 to adjust the optical power of the first light beam and improve the pertinence of the adjustment of the first optical power. Corresponding to the optical path of the first detection device 300, a second power adjustment module 208 can also be arranged between the second detection device 500 and the total spectroscope 202. The second power adjustment module 208 is used to adjust the optical power of the light beam passing through the second power adjustment module 208 when the actual optical power exceeds a preset range, so that the second detection device 500 can work under normal illumination.

[0067] The system may also include a total collimator 201 located between the lighting module 100 and the total spectroscope 202, which is used to collimate the lighting beam emitted by the lighting module 100 to improve the concentration of the beam energy. It may also include a first convergent mirror 209 and a first optical fiber 214 between the total spectroscope 202 and the first detection device 300, and a second convergent mirror 210 and a second optical fiber 213 between the total spectroscope 202 and the second detection device 500. The first convergent mirror 209 and the second convergent 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 light beam enters the first optical fiber 214 through the first optical fiber receiving end 212, and the second light beam enters the second optical fiber 213 through the second optical fiber receiving end 211. The first optical fiber 214 and the second optical fiber 213 have a light homogenizing effect.

[0068] refer to Figure 6 As shown, the lighting module 100 outputs a lighting beam, which, after passing through the total collimator 201, becomes collimated light and is incident on the total beam splitter 202. The total beam splitter 202 splits the collimated light into a first light beam and a second light beam, wherein the first light beam is transmitted through the total beam splitter 202, and the second light beam is reflected by the total beam splitter 202.

[0069] After the first light beam is transmitted through the total beam splitter 202, it is incident on the beam splitter module 204. When the beam splitter module 204 works in the light transmission mode, the first light beam is incident on the first power adjustment module 207, and then the first light beam is coupled to the first optical fiber receiving end 212 through the first converging mirror 209, and then introduced into the first detection device 300 through the first optical fiber 214, as illumination light, to illuminate the surface of one side of the object to be tested 400. When the beam splitter module 204 works in the reflection mode, the first light beam passes through the reflection surface with a certain tilt angle with the optical path, is reflected to the reflector 205, and then reflected to the optical power detection module 206. In this way, the optical power detection module 206 and the first power adjustment module 207 are added to the detection system. The two cooperate with the software and hardware control calculation to periodically detect and compensate the light output by the illumination module 100, maintain a stable interference system, and while ensuring the system illumination quality, a dynamic compensation control unit is added to feedback compensate for the attenuation of the laser, further improving the system adaptability and measurement accuracy.

[0070] After being reflected by the total beam splitter 202, the second light beam is reflected to the reflection module 203, and then incident on the second power adjustment module 208, and then coupled to the second optical fiber receiving end 211 through the second converging lens 210, and then introduced into the second detection device 500 by the second optical fiber 213, as illumination light, and incident on the other side surface of the object to be tested 400. In this way, without losing optical power, while collecting the double-sided interference pattern of the object to be tested 400, it is possible to detect whether the optical power of the illumination module 100 remains stable, and compensate in time through the second power adjustment module 208 if it is unstable.

[0071] The first detection device 300 can be an interferometer, for example, 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 irradiated to the first reference mirror 304 through the first beam expander 303. Part of the light of the first light beam that passes through the first reference mirror 304 is irradiated to the first surface to be measured outside the first reference mirror 304 and away from the side of the first beam expander 303, and then 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 of the first light beam reflected by the first reference mirror 304 is used as the 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 obtain interference information between the first reflected light beam and the second reflected light beam as a first detection signal.

[0072] The second detection device 500 can be an interferometer, for example, 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 light beam is reflected by the second beam splitter 307 and then irradiated to the second reference mirror 310 through the second beam expander 309. Part of the light of the second light beam passes through the second reference mirror 310 and irradiates the second surface to be measured outside the second reference mirror 310 and away from the side of the second beam expander 309, and then reflects to obtain a third reflected light beam. The third reflected light 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 light of the second light beam reflected by the second reference mirror 310 is used as the fourth reflected light beam. The fourth reflected light 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 interference information of the third reflected light beam and the fourth reflected light beam as a second detection signal.

[0073] The illumination beam emitted by the illumination module 100 may be linearly polarized light, and the first power adjustment module 207 and the second power adjustment module 208 include polarizers, and the optical power of the polarized light beam is adjusted by adjusting the polarization direction of the polarizers, that is, the polarization direction of the polarizer of the first power adjustment module 207 may be adjusted to adjust the optical power of the first beam, and the polarization direction of the polarizer of the second power adjustment module 208 may be adjusted to adjust the optical power of the second beam. When the first detection device 300 and the second detection device 500 are interferometers, linearly polarized light is conducive to improving the realization of a more obvious interference phenomenon and obtaining a high-contrast interference pattern.

[0074] The first surface to be measured and the second surface to be measured are surfaces on different sides of the same object to be measured 400. The first detection device 300 may further include a first quarter wave plate 302 between the first beam expander 303 and the first beam splitter 301, which is used to convert linear polarized light into circular polarized light. The second detection device 500 also includes a second quarter wave plate 308 between the second beam expander 309 and the second beam splitter 307, which is used to convert linear polarized light into circular polarized light. The fast axis directions of the first quarter wave plate 302 and the second quarter wave plate 308 are orthogonal directions. The first beam splitter 301 and the second beam splitter 307 are polarization beam splitters, so as to realize the separate detection of the first surface to be measured and the second surface to be measured.

[0075] refer to Figure 6As shown, in the first detection device 300, the first light beam is reflected by the first beam splitter 301 and enters the first detection optical path, and then passes through the first quarter wave plate 302 to form circularly polarized light, and the circularly polarized light is expanded by the first beam expander 303, and the collimated light after the expansion passes through the first reference mirror 304 and is incident on the first surface to be measured of the object to be measured 400. The light reflected by the first surface to be measured and the light reflected by the first reference mirror 304 interfere, and then enter the first beam splitter 301 and transmit, and then pass through the first relay lens group 305 to form an image to the first detector 306. Similarly, in the second detection device 500, the second light beam is reflected by the second beam splitter 307 and enters the second detection optical path, and then passes through the second quarter wave plate 308 to form circularly polarized light, and the circularly polarized light is expanded by the second beam expander 309, and the collimated light after the expansion passes through the second reference mirror 310 and is incident on the second surface to be measured of the object to be measured 400. The light reflected by the second surface to be measured interferes with the light reflected by the second reference mirror 310 , enters the second beam splitter 307 and is transmitted, and then passes through the second relay lens group 311 and is imaged to the second detector 312 .

[0076] Among them, the first beam splitter 301 and the second beam splitter 307 are polarization beam splitters, which can reflect all the incident linearly polarized light s light into the interference light path. The fast axis directions of the first quarter wave plate 302 and the second quarter wave plate 308 are orthogonal directions. For example, the fast axis direction and the optical axis direction are respectively + / -45°, so that the s light passing through the first quarter wave plate 302 and the second quarter wave plate 308 is converted into left-handed polarized light and right-handed polarized light (both are circularly polarized light). In this way, the circularly polarized light reflected by the first surface to be measured and the first reference mirror on one side of the first quarter wave plate 302 forms p light in an orthogonal direction to the polarization direction of the s light when incident from the first beam splitter 301 after passing through the first quarter wave plate 302 again, and is completely transmitted from the first beam splitter into the first detector; similarly, the circularly polarized light reflected by the second surface to be measured and the second reference mirror on one side of the second quarter wave plate 308 forms p light in an orthogonal direction to the polarization direction of the s light when incident from the second beam splitter after passing through the second quarter wave plate 308 again, and is completely transmitted from the second beam splitter into the second detector.

[0077] On the contrary, the s light incident from the first beam splitter 301 forms circular polarized light after passing through the first quarter wave plate 302, and then passes through the object to be tested or is incident on the opposite side light path from the periphery of the object to be tested, and then passes through the second quarter wave plate 308, the s light polarization direction will be maintained and reflected from the light path by the second beam splitter, and will not become p light and enter the second detector; correspondingly, the s light incident from the second beam splitter forms circular polarized light after passing through the second quarter wave plate 308, and then passes through the object to be tested or is incident on the opposite side light path from the periphery of the object to be tested, and then passes through the first quarter wave plate 302, the s light polarization square will be maintained and reflected from the light path by the first beam splitter, and will not become p light and enter the first detector. In this way, the two interference light paths can be prevented from interfering with each other, and the two surfaces to be tested can be detected separately.

[0078] The object to be tested 400 can be a wafer, so that both sides of the wafer are tested. This kind of detection requires high environmental and lighting stability to meet the repeatability index within the nanometer level. As a key module for interference surface measurement, the lighting module provides uniform lighting conditions with good speckle control for the Fizeau interferometer. The interference pattern formed by the interference between the reference mirror and the surface of the wafer to be tested has a great influence on the contrast of the interference fringes in terms of overall brightness and uniformity. Therefore, it is very important to add a stable and reliable monitoring unit in the illumination optical path.

[0079] An embodiment of the present application provides a detection system, which may include an illumination module and a first detection device, as well as a spectroscopic module and a first power adjustment module between the illumination module and the first detection device, the spectroscopic module being used to periodically switch the working mode, when the working mode is the light transmission mode, the illumination light beam passes through the spectroscopic module and the first power adjustment module to enter the first detection device, when the working mode is the reflection mode, the illumination light beam enters the optical power detection module after being reflected by the spectroscopic module, the optical power detection module is used to perform optical power detection on the entering light beam to obtain the actual optical power, the first power adjustment module is used to adjust the power of the light beam passing through the first power adjustment module when the actual optical power exceeds a preset range, so that the working mode can be switched by the spectroscopic module to respectively realize the actual illumination and optical power detection of the illumination light beam in different working modes, that is, the illumination light beam passes through full light illumination during the actual illumination process to ensure the illumination effect, and performs full light optical power detection in the intervals between the actual illumination of the illumination light beam, so as to realize accurate optical power detection and thus realize accurate adjustment of the optical power, and when the working mode is switched quickly, the actual illumination of the illumination light beam is less affected or even has no effect.

[0080] Based on the detection system provided in the above embodiments, the embodiments of the present application also provide an optical power adjustment method, which is applied to the aforementioned detection system and may include: when the actual optical power exceeds a preset range, adjusting the optical power of the light beam passing through the first power adjustment module to adjust the intensity of the first detection signal.

[0081] In an embodiment of the present application, when the actual optical power exceeds the preset range, it means that the output power of the lighting module has attenuated to an unacceptable range. In this case, the optical power of the light beam passing through the first power adjustment module can be adjusted to maintain the stability of the lighting environment during the product life cycle and ensure the measurement accuracy of the stability of the detection system.

[0082] Specifically, when the actual optical power is less than the lower limit of the preset range, the optical power of the light beam passing through the first power adjustment module can be increased. In specific implementation, when the actual optical power is less than the lower limit of the preset range, the required optical power can be determined according to the lower limit of the preset range; the optical power of the light beam passing through the first power adjustment module can be increased according to the required optical power, so that the optical power of the light beam is increased, the signal quality of the first detection signal is improved, and the detection accuracy is improved. The preset range can be determined based on the historical detection optical power, which is stored in the device as a constant to achieve optical power adjustment.

[0083] Specifically, the illumination light beam is linearly polarized, and the first power adjustment module includes a polarizer. Then, when the actual light power exceeds a preset range, the polarization direction of the polarizer can be adjusted to adjust the light power of the light beam passing through the first power adjustment module. In specific implementation, when the actual light power exceeds the preset range, the required polarization direction of the polarizer can be determined according to the required light power; according to the required polarization direction, the polarization direction of the polarizer is adjusted to increase the light power of the light beam passing through the first power adjustment module. This method can achieve accurate control of the light power. The angle between the polarization direction of the incident linear polarized light and the polarization direction of the polarizer is different, and the ratio of the linear polarized light transmission is different. Then, the angle between the polarization direction of the incident linear polarized light and the polarization direction of the polarizer can be determined according to the actual light power and the required light power, and then the required polarization direction of the polarizer is determined to achieve power adjustment.

[0084] When the required optical power remains constant, the required polarization direction has a corresponding relationship with the actual optical power. After the actual optical power attenuates, the required polarization direction can be determined according to the corresponding relationship, and then the polarizer can be adjusted to compensate the optical power to the required optical power. In other words, in actual operation, the polarization direction of the polarizer is usually not parallel to the polarization direction of the illumination beam, so as to reserve a compensation range and realize subsequent compensation. During the equipment debugging stage, the corresponding relationship between different required polarization directions and different actual optical powers can be saved and saved in the device for later use.

[0085] Afterwards, if the intensity of the first detection signal meets the preset conditions, the adjustment of the optical power of the light beam passing through the first power adjustment module is stopped. That is, the first detection signal can also be obtained, and whether the optical power adjustment of the light beam meets the demand can be determined according to the intensity of the first detection signal. If the intensity of the first detection signal meets the preset conditions, it means that the quality of the first detection signal is high, so the adjustment of the optical power of the light 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, and the intensity of the first detection signal is used as a verification item for the optical power adjustment, so as to achieve simultaneous detection of the optical power and the quality of the detection signal for dynamic compensation control, so that the adjustment of the optical power can make the intensity of the first detection signal meet the preset conditions, achieve accurate adjustment of the optical power, improve the system adaptability, ensure the stability of the detection system lighting imaging, and ensure the system measurement accuracy.

[0086] Due to its high resolution and high accuracy, the changes in lasers detected by optical power detectors are more accurate, and can more intuitively and accurately reflect changes in lighting conditions. However, the lighting fringes required by the interferometer are based on the SNR representation of the interference pattern. If the SNR of the interference pattern is used directly to represent changes in lighting patterns, it is not accurate enough. This is because there are many disturbance errors in the system, such as test repeatability, vibration, environmental disturbances, etc., which will affect the numerical changes in SNR. Therefore, it is impossible to use the SNR value to characterize changes in lighting lasers or lighting patterns. Therefore, it is necessary to establish a connection between an optical power meter that directly characterizes laser changes and the SNR that directly characterizes the interference lighting effect, and indirectly verify the impact of lighting and interference effects, which can be of great help in maintaining stable lighting adjustments.

[0087] When the first detection signal includes the first interference image, if the contrast (SNR) of the first interference image is within a preset contrast range, it means that the first interference image can accurately reflect the characteristics of the interference fringes, and it can be considered that the intensity of the first detection signal meets the preset conditions, and the adjustment of the optical power of the light beam passing through the first optical power adjustment module can be stopped, and the contrast of the first interference image is used as a verification item, which is conducive to obtaining a first interference image with higher quality and improving the detection accuracy. The preset contrast range can be determined according to the contrast of the historical image, which is stored in the device as a constant to realize the verification of the optical power adjustment.

[0088] The first interference image is obtained after the actual optical power. The first interference image and the actual optical power can be obtained in different sampling periods and the sampling periods between the acquisition times of the two do not exceed the preset number, so that the first interference image can reflect the adjustment effect of the optical power in a more timely manner. In specific implementation, the actual optical power and the interference image in the same sampling period can be saved as a basis for subsequent comparison, that is, the synchronous detection of the optical power and the interference image is realized and the dynamic compensation of the optical power is realized accordingly, so as to ensure the stability of the system illumination imaging and the measurement accuracy of the system.

[0089] The contrast of the first interference image may be the contrast within a fixed region of the first interference image, and the contrast within the fixed region will represent the overall contrast of the first interference image. Figure 7 , which is a schematic diagram of a first interference image provided in an embodiment of the present application, the contrast in the fixed area 1001 (the area within the rectangular frame formed by white lines) is 0.8958.

[0090] In the embodiment of the present application, when the detection system includes a second power adjustment module, the optical power of the light beam passing through the second power adjustment module can also be adjusted when the actual optical power exceeds the preset range to adjust the intensity of the second detection signal. In addition, if the intensity of the second detection signal meets the preset conditions, it means that the quality of the second detection signal is high, so the adjustment of the optical power of the light beam passing through the second power adjustment module can be stopped, so that the optical power can be adjusted based on the actual optical power, and the intensity of the second 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 second detection signal meet the preset conditions, and the optical power can be accurately adjusted.

[0091] Specifically, when the actual optical power is less than the lower limit of the preset range, the optical power of the light beam passing through the second power adjustment module is increased. In specific implementation, when the actual optical power is less than the lower limit of the preset range, the required optical power of the second light beam can be determined according to the lower limit of the preset range; the optical power of the light beam passing through the second power adjustment module is increased according to the required optical power of the second light beam, so that the optical power of the second light beam is increased, the signal quality of the second detection signal is improved, and the detection accuracy is improved.

[0092] Specifically, the linear polarized light of the illumination light beam, the second power adjustment module includes a polarizer, then when the actual optical power exceeds the preset range, the polarization direction of the polarizer is adjusted to adjust the optical power of the light beam passing through the second power adjustment module. In specific implementation, when the actual optical power exceeds the preset range, the required polarization direction of the polarizer can be determined according to the required optical power of the second light beam; according to the required polarization direction, the polarization direction of the polarizer is adjusted to increase the optical power of the light beam passing through the second power adjustment module, this method can achieve accurate control of optical power. The angle between the polarization direction of the incident linear polarized light and the polarization direction of the polarizer is different, and the ratio of linear polarized light transmission is different. Then, the angle between the polarization direction of the incident linear polarized light and the polarization direction of the polarizer can be determined according to the actual optical power and the required optical power, and then the required polarization direction of the polarizer is determined to achieve power adjustment.

[0093] When the required optical power remains constant, the required polarization direction corresponds to the actual optical power. After the actual optical power attenuates, the required polarization direction can be determined based on the corresponding relationship, and then the polarizer can be adjusted to compensate the optical power to the required optical power. In other words, in actual operation, the polarization direction of the polarizer is usually not parallel to the polarization direction of the illumination beam, so as to reserve a compensation range and realize subsequent compensation. During the equipment debugging stage, the corresponding relationship between different required polarization directions and different actual optical powers can be saved and saved in the device for later use.

[0094] When the second detection signal includes a second interference image, if the contrast (SNR) of the second interference image is within a preset contrast range, indicating that the second interference image can accurately reflect the characteristics of the interference fringes, it can be considered that the intensity of the second detection signal meets the preset conditions, and the adjustment of the optical power of the light beam passing through the second optical power adjustment module can be stopped, and the contrast of the second interference image is used as a verification item, which is conducive to obtaining a second interference image with higher quality and improving the detection accuracy. Among them, the contrast of the second interference image can be the contrast within a fixed area of ​​the second interference image, and the contrast within the fixed area will represent the overall contrast of the second interference image.

[0095] An embodiment of the present application provides a control method for a detection system. 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. 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. 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 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.

[0096] A person skilled in the art can understand that all or part of the steps of implementing the above method embodiment can be completed by program instruction hardware, and the above program can be stored in a computer-readable storage medium. When the program is executed, it executes the steps of the above method embodiment; and the above storage medium can be at least one of the following media: read-only memory (English: Read-only Memory, abbreviated: ROM), RAM, magnetic disk or optical disk, etc. Various media that can store program codes.

[0097] Each embodiment in this specification is described in a progressive manner, and the same or similar parts between the embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the method embodiment, since it is basically similar to the system embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the system embodiment.

[0098] The above is only a preferred implementation of the present application. Although the present application has been disclosed as a preferred embodiment, it is not intended to limit the present application. Any technician familiar with the art can use the above disclosed methods and technical contents to make many possible changes and modifications to the technical solution of the present application without departing from the scope of the technical solution of the present application, or modify it into an equivalent embodiment of equivalent changes. Therefore, any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the present application without departing from the content of the technical solution of the present application still falls within the scope of protection of the technical solution of the present application.

Claims

1. A detection system, characterized in that: include: A lighting module, for providing a lighting beam; A first detection device, used for detecting a first surface to be detected to obtain a first detection signal; A spectroscopic module and a first power adjustment module are provided between the lighting module and the first detection device, wherein the spectroscopic module is used to periodically switch the working mode. When the working mode is the light transmission mode, the lighting light beam passes through the spectroscopic module and the first power adjustment module to enter the first detection device. When the working mode is the reflection mode, the lighting light beam enters the optical power detection module after being reflected by the spectroscopic module. The optical power detection module is used to perform optical power detection on the incoming light beam to obtain the actual optical power. The first power adjustment module is used to adjust the optical power of the light beam passing through the first power adjustment module when the actual optical power exceeds a preset range.

2. The system according to claim 1, characterized in that The light splitting module includes a semi-transparent and semi-reflective module, the semi-transparent and semi-reflective module includes a light-transmitting path and a reflective surface, the light-transmitting path includes a first surface and a second surface, the material between the first surface and the second surface is a transparent material, the light-transmitting path and the reflective surface are periodically switched to the propagation path of the illumination light beam, so that the semi-transparent and semi-reflective module periodically switches the working mode; When the light-transmitting passage is switched to the propagation path of the illumination light beam, the working mode is the light-transmitting mode; when the reflective surface is switched to the propagation path of the illumination light beam, the working mode is the reflective mode.

3. The system according to claim 2, characterized in that The semi-transmissive and semi-reflective module rotates at a preset rate so that the light-transmitting passage and the reflective surface are periodically switched to the propagation path of the illumination light beam.

4. The system according to claim 3, characterized in that The rotation axis of the semi-transparent and semi-reflective module is parallel to and does not overlap with the propagation path of the illumination light 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 passage, 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 light beam.

5. The system according to claim 3, characterized in that The rotation axis of the semi-transparent and semi-reflective module is perpendicular to the propagation direction of the illumination light beam, and the semi-transparent and semi-reflective module has the first surface, the second surface, the third surface and the 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 reflective surfaces.

6. The system according to claim 5, characterized in that The first surface and the second surface are arranged in parallel, the angle between the third surface and the first surface is equal to the angle between the third surface and the second surface, and the third surface and the fourth surface are not parallel.

7. The system according to claim 3, characterized in that The rotation speed of the semi-transmissive and semi-reflective module enables a single sampling of the first detection device to correspond to at least one light transmission mode and one reflection mode.

8. The system according to any one of claims 1 to 7, characterized in that: The system further comprises: A second detection device, used for detecting a second surface to be detected to obtain a second detection signal; The total beam splitter is used to split the illumination light beam into a first light beam and a second light beam, wherein the first light beam enters the first detection device and the second light beam enters the second detection device.

9. The system according to claim 8, characterized in that 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 irradiated to the first reference mirror through the first beam expander. Part of the light of the first light beam that passes through the first reference mirror is irradiated to a first surface to be measured outside the first reference mirror and away from the first beam expander. Then, it 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. Part of the light of the first light beam reflected by the first reference mirror is used 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 obtain 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 then irradiated to the second reference mirror through the second beam expander. Part of the light of the second light beam that passes through the second reference mirror is irradiated to a second surface to be measured outside the second reference mirror and away from the second beam expander, and then is reflected 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 of the second light beam reflected by the second reference mirror is used as 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 is used to obtain interference information of the third reflected light beam and the fourth reflected light beam as the second detection signal.

10. The system according to claim 8, characterized in that The system further comprises: A second power adjustment module is provided between the total spectroscope and the second detection device, wherein the second power adjustment module is used to adjust the optical power of the light beam passing through the second power adjustment module when the actual optical power exceeds a preset range.

11. The system according to claim 10, characterized in that The illumination light beam is linearly polarized light. The first power adjustment module and the second power adjustment module include polarizers. The light power of the light beam passing through the polarizers is adjusted by adjusting the polarization directions of the polarizers.

12. The system according to claim 11, characterized in that The first surface to be measured and the second surface to be measured are surfaces on different sides of the same object to be measured, the first detection device also includes a first quarter wave plate between the first beam expander and the first beam splitter, the second detection device also 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 directions, and the first beam splitter and the second beam splitter are polarization beam splitters.

13. The system according to claim 8, characterized in that The system further comprises: A total collimator located between the lighting module and the total beam splitter; a first converging mirror and a first optical fiber between the total spectroscope and the first detection device; A second converging mirror and a second optical fiber between the total beam splitter and the second detection device.

14. The system according to any one of claims 1 to 7, characterized in that: The system further comprises: The reflector between the light splitting module and the optical power detection module is used to reflect the light beam reflected by the light splitting module to the optical power detection module.

15. A method for adjusting optical power, characterized in that: Applied to the detection system according to any one of claims 1 to 14, the method comprising: 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.

16. The method according to claim 15, characterized in that When the actual optical power exceeds a preset range, adjusting the optical power of the light beam passing through the first power adjustment module comprises: When the actual optical power is less than a lower limit of a preset range, the optical power of the light beam passing through the first power adjustment module is increased.

17. The method according to claim 15, characterized in that The illumination light beam is linearly polarized, and the first power adjustment module includes a polarizer. 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, including: When the actual optical power exceeds a preset range, the polarization direction of the polarizer is adjusted to adjust the optical power of the light beam passing through the first power adjustment module.

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