High-precision detection and calculation method for optical reflection and mechanical deflection center of precise rotating mirror

Abstract

The invention discloses a high-precision detection and calculation method for optical reflection and mechanical deflection centers of a precise rotating mirror. According to the invention, the direction of the laser beam emitted by the laser is adjusted, the precise rotating mirror is controlled to carry out sine scanning rotation at the same time, and the corresponding transverse displacement change of the beam is calculated, so that the target incident angle of the measurement beam incident on the precise rotating mirror is determined; under a target incident angle, a laser beam emitted by a laser or a precise rotating mirror is translated, the precise rotating mirror is controlled to perform sine scanning rotation, corresponding longitudinal optical path change of an optical path is calculated, and the position of an optical reflection center of the precise rotating mirror is detected by utilizing the longitudinal optical path change of the optical path and transverse displacement change of the laser beam. And the position of the mechanical deflection center of the precise rotating mirror is detected. According to the invention, high-precision detection of the positions of the optical reflection center and the mechanical deflection center of the precise rotating mirror can be realized, and the optical path error of an optical path is effectively reduced.

Description

Technical Field

[0001] The present invention relates to the field of optical detection technology, and particularly to a high-precision detection and calculation method for the optical reflection and mechanical deflection center of a precision rotating mirror. Background Art

[0002] Precision rotating mirrors are commonly used in optical systems to control the rapid angular deflection of light beams, achieving the adjustment of beam pointing and stabilizing the optical axis of the optical system. They have the advantages of small size, high precision, and fast response speed. In some optical systems with laser ranging functions, extremely strict requirements are imposed on the stability of the optical path. During the propagation of light beams, whether passing through the interior of a transmission element or on the surface of an optical element in the beam path, angular deviations may occur. Such deviations will cause changes in the optical path length of the light path, thereby affecting the incident point position of the light beam on the detector and the wavefront characteristics, and further interfering with the optical path length signal read by the detector.

[0003] Among these factors affecting the optical path length signal, the effects related to the precision rotating mirror can be summarized as the lever arm effect and the piston effect. The lever arm effect is a pure angular jitter coupling effect. If the incident light beam is incident exactly at the optical reflection center of the precision rotating mirror, and the mechanical deflection center of the precision rotating mirror coincides with the optical reflection center, when the reflecting surface of the precision rotating mirror rotates by a certain angle around the optical reflection center, according to the law of reflection, the rotation angle of the light beam axis is twice the rotation angle of the reflecting surface, and the light beam will propagate along a different light beam path from the original one and finally be incident at different positions on the detector. The optical path length error caused by this process can be calculated as , where is the distance from the reflection point of the incident light beam to the PD detector, is the rotation angle of the reflecting surface of the precision rotating mirror around the optical reflection center.

[0004] The lever arm effect describes the situation where the incident light beam is incident exactly at the optical reflection center of the precision rotating mirror and the mechanical deflection center of the precision rotating mirror coincides with the optical reflection center. However, in an actual optical system, it is difficult to locate the optical reflection center of the precision rotating mirror, so it is difficult to ensure that the incident point of the light beam coincides with the optical reflection center of the precision rotating mirror. And due to factors such as mechanical design and modulation deviation, the mechanical deflection center and the optical reflection center of the precision rotating mirror usually do not coincide. In this case, during the rotation of the precision rotating mirror, the reflecting surface will move back and forth like a piston, thus affecting the incident point position of the light beam and resulting in an optical path length error. This effect is called the piston effect, and the resulting optical path length error is , is the incident angle of the light beam, represents the longitudinal axis component of the distance between the reflection point and the rotation center, represents the transverse axis component of the distance between the reflection point and the rotation center, is the angle by which the reflecting surface rotates about the rotation center. SUMMARY OF THE INVENTION

[0005] The present invention provides a high-precision detection and calculation method for the optical reflection center and mechanical deflection center of a precision rotating mirror, which is used to solve the technical problem that the existing optical system is difficult to accurately detect the positions of the optical reflection center and mechanical deflection center of the precision rotating mirror, thereby causing optical path optical path errors.

[0006] The first aspect of the present invention provides a high-precision detection and calculation method for the optical reflection center and mechanical deflection center of a precision rotating mirror, and the method includes:

[0007] Emit a laser beam through a laser, split the laser beam into a measurement beam and a reference beam; direct the measurement beam towards the precision rotating mirror, reflect the measurement beam by the reflection plane of the precision rotating mirror onto a detector assembly, and at the same time, direct the reference beam onto the detector assembly, so that the measurement beam and the reference beam interfere on the detector assembly to generate a detection signal;

[0008] Adjust the emission direction of the laser beam of the laser to adjust the incident angle of the measurement beam on the reflection plane, and at the same time, control the precision rotating mirror to perform a sinusoidal scanning rotation to obtain a plurality of detection signals corresponding to different incident angles during the scanning period of the precision rotating mirror performing a sinusoidal scanning rotation; process different detection signals to obtain an analysis diagram of the change in the lateral displacement of the beam;

[0009] Determine a target lateral waveform from the analysis diagram of the change in the lateral displacement of the beam, and use the incident angle corresponding to the target lateral waveform as the target incident angle;

[0010] Adjust the incident angle of the measurement beam on the reflection plane to the target incident angle, translate the laser or the precision rotating mirror to adjust the incident point position of the measurement beam on the reflection plane, and at the same time, control the precision rotating mirror to perform a sinusoidal scanning rotation to obtain a plurality of detection signals corresponding to different incident point positions during the scanning period of the precision rotating mirror performing a sinusoidal scanning rotation; process different detection signals to obtain an analysis diagram of the change in the longitudinal optical path of the optical path;

[0011] Determine a target longitudinal waveform from the analysis diagram of the change in the longitudinal optical path of the optical path, and use the incident point position corresponding to the target longitudinal waveform as the position of the optical reflection center of the precision rotating mirror;

[0012] According to the position of the optical reflection center of the precision rotating mirror, calculate the distance value between the optical reflection center and the mechanical deflection center of the precision rotating mirror, and then detect the position of the mechanical deflection center of the precision rotating mirror.

[0013] Specifically, the step of adjusting the emission direction of the laser beam of the laser to adjust the incident angle of the measurement beam on the reflection plane, and simultaneously controlling the precision rotating mirror to perform a sinusoidal scanning rotation to obtain a plurality of detection signals corresponding to different incident angles during the scanning period of the precision rotating mirror performing a sinusoidal scanning rotation; the step of processing the beam lateral displacement change analysis diagram based on different detection signals includes:

[0014] Adjust the emission direction of the laser beam of the laser to adjust the incident angle of the measurement beam on the reflection plane, and simultaneously control the precision rotating mirror to perform a sinusoidal scanning rotation, so as to adjust the detection position of the measurement beam on the detector assembly;

[0015] Based on the detection signals corresponding to different detection positions, calculate the beam lateral displacement change amounts corresponding to different detection positions by differential power sensing technology or by using spot reading technology;

[0016] Process to obtain a lateral waveform in which the beam lateral displacement change amount varies with the scanning time of the precision rotating mirror performing a sinusoidal scanning rotation under multiple different incident angle conditions, and generate a beam lateral displacement change analysis diagram based on multiple lateral waveforms.

[0017] Specifically, the step of determining a target lateral waveform from the beam lateral displacement change analysis diagram and using the incident angle corresponding to the target lateral waveform as the target incident angle includes: based on the beam lateral displacement change analysis diagram, taking the lateral waveform with the smallest beam lateral offset amplitude as the target lateral waveform; using the incident angle corresponding to the target lateral waveform as the target incident angle.

[0018] Specifically, the step of adjusting the incident angle of the measurement beam on the reflection plane to the target incident angle, translating the laser or the precision rotating mirror to adjust the incident point position of the measurement beam on the reflection plane, and simultaneously controlling the precision rotating mirror to perform a sinusoidal scanning rotation to obtain a plurality of detection signals corresponding to different incident point positions during the scanning period of the precision rotating mirror performing a sinusoidal scanning rotation; the step of processing the optical path longitudinal optical path change analysis diagram based on different detection signals includes:

[0019] Adjust the incident angle of the measurement beam on the reflection plane to the target incident angle, translate the laser or the precision rotating mirror to adjust the incident point position of the measurement beam on the reflection plane, and simultaneously control the precision rotating mirror to perform a sinusoidal scanning rotation, so as to adjust the detection position of the measurement beam on the detector assembly;

[0020] Based on the detection signals corresponding to different detection positions, calculate the optical path longitudinal optical path change amounts corresponding to different detection positions by differential wavefront sensing technology;

[0021] The longitudinal waveform of the change in the longitudinal optical path with respect to the scanning time of the precision rotating mirror's sinusoidal scanning rotation is obtained under conditions of multiple different incident point positions, and an analysis diagram of the change in the longitudinal optical path of the optical path is generated based on multiple longitudinal waveforms.

[0022] Specifically, the step of determining the target longitudinal waveform from the analysis diagram of the change in the longitudinal optical path of the optical path and using the position of the incident point corresponding to the target longitudinal waveform as the position of the optical reflection center of the precision rotating mirror includes: based on the analysis diagram of the change in the longitudinal optical path of the optical path, taking the longitudinal waveform with the smallest change in the longitudinal optical path and whose waveform is always in the positive interval or negative interval during the sinusoidal scanning rotation of the precision rotating mirror as the target longitudinal waveform; using the position of the incident point corresponding to the target longitudinal waveform as the position of the optical reflection center of the precision rotating mirror.

[0023] Specifically, the step of calculating the distance value between the optical reflection center and the mechanical deflection center of the precision rotating mirror according to the position of the optical reflection center of the precision rotating mirror, and then detecting the position of the mechanical deflection center of the precision rotating mirror includes:

[0024] According to the position of the optical reflection center of the precision rotating mirror, measuring the distance values between the optical reflection center and the laser emission point of the laser and the center of the detector assembly respectively, and measuring the included angle formed between the laser emission point of the laser and the normal of the reflection plane of the precision rotating mirror in the initial state and the included angle formed between the center of the detector assembly and the normal of the reflection plane of the precision rotating mirror in the initial state;

[0025] Controlling the precision rotating mirror to rotate by an angle, and calculating the change in the longitudinal optical path and the change in the lateral beam displacement corresponding to the rotation by an angle;

[0026] Based on the preset calculation formulas for the change in the longitudinal optical path and the change in the lateral beam displacement, according to the measured multiple distance values, multiple included angle angles, and the change in the longitudinal optical path and the change in the lateral beam displacement corresponding to the rotation by an angle and the rotation by an angle of the precision rotating mirror, calculating the distance value between the optical reflection center and the mechanical deflection center of the precision rotating mirror, and then detecting the position of the mechanical deflection center of the precision rotating mirror.

[0027] Specifically, the preset calculation formula for the change in the longitudinal optical path is as follows:

[0028]

[0029] In the formula: represents the distance value between the laser emission point of the laser and the optical reflection center of the precision rotating mirror, Represents the distance value between the optical reflection center and the mechanical deflection center of the precision rotating mirror, represents the distance value between the center of the detector assembly and the optical reflection center of the precision rotating mirror; represents the included angle between the beam exit direction of the laser beam emitted by the laser and the ideal light ray, represents the included angle formed between the laser exit point of the laser and the normal of the reflection plane of the precision rotating mirror in the initial state, represents the included angle formed between the center of the detector assembly and the normal of the reflection plane of the precision rotating mirror in the initial state; represents when the precision rotating mirror rotates the longitudinal optical path change amount calculated at the angle;

[0030] Among them, the calculation formula for the preset beam lateral displacement change amount is as follows:

[0031]

[0032] In the formula: represents when the precision rotating mirror rotates the beam lateral displacement change amount calculated at the angle.

[0033] In the second aspect of the present invention, a detection device for the optical reflection center and the mechanical deflection center of a precision rotating mirror is further provided. The device includes: a laser, a first beam splitter, a second beam splitter, a third beam splitter, a first acousto-optic modulator, a second acousto-optic modulator, a precision rotating mirror, and a detector assembly;

[0034] The third beam splitter is used to split the laser beam emitted by the laser into an initial reflected light beam and an initial transmitted light beam, reflect the initial reflected light beam to the first beam splitter, and direct the initial transmitted light beam to the second acousto-optic modulator;

[0035] The first beam splitter is used to reflect the initial reflected light beam to the first acousto-optic modulator; the first acousto-optic modulator is used to shift the frequency of the initial reflected light beam to obtain a reference beam and direct the reference beam to the second beam splitter;

[0036] The second acousto-optic modulator is used to shift the frequency of the initial transmitted light beam to obtain a measurement beam and direct the measurement beam to the precision rotating mirror; the precision rotating mirror is used to reflect the measurement beam to the second beam splitter through the reflection plane;

[0037] The second beam splitter is used to split the reference beam and the measurement beam, and direct the split reference beam and measurement beam onto the detection assembly.

[0038] Specifically, the detector assembly specifically uses a quadrant detector;

[0039] The second beam splitter is specifically configured to split the reference beam into a reference transmitted light beam and a reference reflected light beam, split the measurement beam into a measurement transmitted light beam and a measurement reflected light beam, and direct the reference reflected light beam and the measurement transmitted light beam to the quadrant detector.

[0040] Specifically, the detector assembly is specifically composed of a quadrant detector and a position sensitive detector;

[0041] The second beam splitter is specifically configured to split the reference beam into a reference transmitted light beam and a reference reflected light beam, split the measurement beam into a measurement transmitted light beam and a measurement reflected light beam, direct the reference reflected light beam and the measurement transmitted light beam to the quadrant detector, and direct the reference transmitted light beam and the measurement reflected light beam to the position sensitive detector.

[0042] As can be seen from the above technical solutions, the present invention has the following advantages:

[0043] The present invention provides a high-precision detection and calculation method for the optical reflection and mechanical deflection center of a precision rotating mirror. The method includes: adjusting the emission direction of the laser beam of the laser to adjust the incident angle of the measurement beam on the reflection plane, and simultaneously controlling the precision rotating mirror to perform a sinusoidal scanning rotation to obtain a plurality of detection signals corresponding to different incident angles during the scanning period of the precision rotating mirror performing a sinusoidal scanning rotation; processing the different detection signals to obtain an analysis diagram of the change in the lateral displacement of the beam; determining a target lateral waveform from the analysis diagram of the change in the lateral displacement of the beam, and using the incident angle corresponding to the target lateral waveform as the target incident angle;

[0044] Adjust the incident angle of the measurement beam on the reflection plane to the target incident angle, translate the laser or the precision rotating mirror to adjust the incident point position of the measurement beam on the reflection plane, and simultaneously control the precision rotating mirror to perform a sinusoidal scanning rotation to obtain a plurality of detection signals corresponding to different incident point positions during the scanning period of the precision rotating mirror performing a sinusoidal scanning rotation; processing the different detection signals to obtain an analysis diagram of the change in the longitudinal optical path of the optical path; determining a target longitudinal waveform from the analysis diagram of the change in the longitudinal optical path of the optical path, and using the incident point position corresponding to the target longitudinal waveform as the position of the optical reflection center of the precision rotating mirror; according to the position of the optical reflection center of the precision rotating mirror, calculate the distance value between the optical reflection center and the mechanical deflection center of the precision rotating mirror, and further detect the position of the mechanical deflection center of the precision rotating mirror.

[0045] In the present invention, by adjusting the direction of the laser beam emitted by the laser, and simultaneously controlling the precision rotating mirror to perform sinusoidal scanning rotation, the corresponding change in the lateral displacement of the beam is calculated; then, by translating the laser beam emitted by the laser or the precision rotating mirror, and simultaneously controlling the precision rotating mirror to perform sinusoidal scanning rotation, the corresponding change in the longitudinal optical path of the optical path is calculated. The high-precision detection of the positions of the optical reflection center and the mechanical deflection center of the precision rotating mirror is achieved by using the calculated change in the longitudinal optical path of the optical path and the change in the lateral displacement of the beam, effectively reducing the optical path error, and thus solving the technical problem that the existing optical system is difficult to accurately detect the positions of the optical reflection center and the mechanical deflection center of the precision rotating mirror, thereby causing the optical path error. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0047] Figure 1 It is a flowchart of the steps of a method for high-precision detection and calculation of the optical reflection and mechanical deflection centers of a precision rotating mirror provided by an embodiment of the present invention;

[0048] Figure 2 It is a schematic structural diagram of a detection device for the optical reflection center and mechanical deflection center of a precision rotating mirror provided by an example of the present invention;

[0049] Figure 3 It is a simplified schematic diagram of the optical path provided by an example of the present invention;

[0050] Figure 4 and Figure 5 It is a simulation test analysis diagram provided by an example of the present invention.

[0051] Among them, the reference numerals are: laser 1, first beam splitter 2, first acousto-optic modulator 3, second beam splitter 4, quadrant detector 5, third beam splitter 6, second acousto-optic modulator 7, precision rotating mirror 8, and position sensitive detector 9. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0052] The embodiments of the present invention provide a method for high-precision detection and calculation of the optical reflection and mechanical deflection centers of a precision rotating mirror, which is used to solve the technical problem that the existing optical system is difficult to accurately detect the positions of the optical reflection center and the mechanical deflection center of the precision rotating mirror, thereby causing the optical path error.

[0053] In order to make the objectives, features, and advantages of the present invention more obvious and understandable, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the embodiments described below are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts belong to the scope of protection of the present invention.

[0054] Please refer to Figure 1 , the first aspect of the present invention provides a high-precision detection and calculation method for the optical reflection center and mechanical deflection center of a precision rotating mirror. The method includes:

[0055] Step 101: Emit a laser beam through a laser, split the laser beam into a measurement beam and a reference beam; direct the measurement beam towards the precision rotating mirror, reflect the measurement beam to the detector assembly by the reflection plane of the precision rotating mirror, and at the same time, direct the reference beam onto the detector assembly, so that the measurement beam and the reference beam interfere on the detector assembly to generate a detection signal.

[0056] This embodiment is applied to a detection device for the optical reflection center and mechanical deflection center of a precision rotating mirror, as Figure 2 shown. The device includes: a laser 1, a first beam splitter 2, a second beam splitter 4, a third beam splitter 6, a first acousto-optic modulator 3 and a second acousto-optic modulator 7, a precision rotating mirror, and a detector assembly.

[0057] The laser is used to emit a laser beam. The laser beam is split by the third beam splitter 6 into an initial reflected light beam and an initial transmitted light beam. The initial reflected light beam forms a reference beam after passing through the first beam splitter 2 and the first acousto-optic modulator 3. The initial transmitted light beam passes through the second acousto-optic modulator 7 and is reflected by the precision rotating mirror, and finally, the measurement beam and the reference beam are split by the second beam splitter 4 and directed towards the detector assembly. The detector assembly can be set as a quadrant detector according to actual test requirements, or a quadrant detector and a position-sensitive detector.

[0058] It can be understood that the measurement beam and the reference beam are light beams with different frequencies, and light beams with different frequencies will undergo heterodyne beat interference on the quadrant detector, thereby obtaining a detection signal. Subsequently, the lateral displacement change of the measurement beam and the longitudinal optical path change of the optical path can be quickly calculated using the detection signal.

[0059] Step 102: Adjust the emission direction of the laser beam of the laser to adjust the incident angle of the measurement beam on the reflection plane. At the same time, control the precision rotating mirror to perform a sinusoidal scanning rotation, and obtain a plurality of detection signals corresponding to different incident angles during the sinusoidal scanning rotation of the precision rotating mirror; process the different detection signals to obtain an analysis diagram of the change in the lateral displacement of the beam.

[0060] In order to accurately detect the positions of the optical reflection center and the mechanical deflection center of the precision rotating mirror and reduce the optical path length error. The present invention conducts a simulation test on the change of the optical path length based on the detection device. For the sake of easy understanding, in this example, the detector assembly specifically uses a four-quadrant detector. As Figure 3 shown, Figure 3 is a simplified schematic diagram of the optical path of the detection device for this example. It should be noted that in actual applications, if the detector assembly uses a four-quadrant detector 5 and a position-sensitive detector 9, since the optical path of the position-sensitive detector is completely symmetric with respect to the second beam splitter 4 compared to the optical path of the four-quadrant detector, the simplified schematic diagram of the optical path of the beam from the laser to the precision rotating mirror to the position-sensitive detector can also be equivalent to Figure 3 .

[0061] In Figure 3 , assuming that the laser emission point of the laser is located on the left side of the normal line of the reflection plane of the precision rotating mirror in the initial state at an angle direction, the laser emission point is at a distance of from the optical reflection center point of the precision rotating mirror. The mechanical deflection center of the precision rotating mirror is located at a distance of below the normal line direction of the reflection plane of the precision rotating mirror; the center of the four-quadrant detector 5 is located on the right side of the normal line direction of the reflection plane of the precision rotating mirror at an angle direction ( the angle is generally 45°), and the center of the four-quadrant detector 5 is at a distance of from the optical reflection center point of the precision rotating mirror optics.

[0062] In the ideal case, when the rotation angle of the precision rotating mirror is 0, at this time, the measurement beam is normally incident on the optical reflection center of the precision rotating mirror, and the beam incident angle is . However, in the actual alignment process, it is impossible to determine whether the beam is incident on the optical reflection center of the precision rotating mirror. Assume that at this time, the beam emission direction deviates from the ideal light by an angle, and after being incident on the point position of the reflection plane of the precision rotating mirror, it is reflected to the point position of the four-quadrant detector 5.

[0063] Then when the reflection plane of the precision rotating mirror rotates clockwise around the mechanical deflection center by an angle, the measurement beam will be incident on the point of the reflection plane of the precision rotating mirror and be reflected on the point of the quadrant detector. Through geometric trigonometric relations, the longitudinal optical path change of the optical path from the beam exit point to the quadrant detector 5 caused by the rotation of the precision rotating mirror by an angle and the lateral displacement change of the beam at the incident point on the detector can be deduced as shown in the following formula:

[0064] The preset calculation formula for the longitudinal optical path change is expressed as:

[0065] (1)

[0066] wherein, the preset calculation formula for the lateral displacement change of the beam is expressed as:

[0067] (2)

[0068] Through the above formulas, the relationship between the longitudinal optical path change of the measurement beam and the lateral displacement change of the beam at the incident point on the detector generated by the precision rotating mirror performing a sinusoidal scanning rotation with an amplitude of 3 mrad around the mechanical rotation center can be simulated under different ideal incident angles of the beam and when there is a deviation between the beam incident point and the optical reflection center of the precision rotating mirror (i.e., is different). In this example, the beam incident angles are analyzed successively as 30°, 45°, and 60°, as shown in Figure 4 and Figure 5 .

[0069] It can be observed from Figure 4 that the lateral displacement change of the beam at the incident point on the quadrant detector 5 is consistent with the rotation trend of the reflection surface of the precision rotating mirror. When the beam incident angle is not equal to 45°, the amplitude of the lateral displacement change of the beam at the incident point on the detector decreases as the beam incident angle approaches 45°. When the beam incident angle is equal to 45°, the amplitude of the lateral displacement change of the beam at the incident point on the detector is the smallest.

[0070] It can be observed from Figure 5 that the longitudinal optical path change varies with the rotation of the reflection surface of the precision rotating mirror. When the beam incident angle is not equal to 45°, the longitudinal optical path change Decreases as the incident angle of the light beam approaches the 45° direction and is opposite to the rotation trend of the reflecting surface of the precision rotating mirror. When the incident angle is equal to 45°, the change in the longitudinal optical path of the optical path will vary with the incident point as the distance becomes smaller. When it is equal to 0, that is, when the light beam is incident at 45° on the reflection center, at this time the change in the longitudinal optical path of the scanning optical path with the reflecting plane of the precision rotating mirror is less than 0 (or greater than 0, and the positive or negative depends on the definition of the change in the optical path during the actual measurement process).

[0071] Therefore, based on the principle obtained from the above simulation analysis, the present invention can detect the amplitudes of the change in the longitudinal optical path and the change in the lateral displacement of the reflected light beam of the precision rotating mirror by modulating the rotation angle of the precision rotating mirror, so as to detect the positions of the optical reflection center and the mechanical deflection center of the precision rotating mirror.

[0072] This step specifically includes the following sub-steps:

[0073] Sub-step 1021, adjust the output direction of the laser beam of the laser to adjust the incident angle of the measurement light beam on the reflection plane, and at the same time control the precision rotating mirror to perform a sinusoidal scanning rotation, so as to adjust the detection position of the measurement light beam on the detector assembly;

[0074] In this sub-step, by adjusting the optical system of the laser to change the output direction of the laser beam, the adjustment of the incident angle of the measurement light beam on the reflection plane is realized. While adjusting the incident angle of the measurement light beam on the reflection plane, control the precision rotating mirror to perform a sinusoidal scanning rotation (such as a sinusoidal scanning rotation with an amplitude of 3 mrad); then the scanning period of the sinusoidal scanning rotation of the precision rotating mirror can be used as the adjustment period for adjusting the output direction of the laser beam of the laser.

[0075] Exemplarily, when adjusting the output direction of the laser beam of the laser to the first output direction, it is necessary to control the precision rotating mirror to perform a sinusoidal scanning rotation and complete one scanning cycle, and then continue to adjust the output direction of the laser beam of the laser to the second output direction, and control the precision rotating mirror to perform a sinusoidal scanning rotation and complete one scanning cycle, and so on until the measurement light beam cannot be incident on the reflection plane.

[0076] Sub-step 1022, based on the detection signals corresponding to different detection positions, calculate the change in the lateral displacement of the light beam corresponding to different detection positions by using differential power sensing technology or spot reading technology;

[0077] It is understandable that if only one quadrant detector is used in the detector assembly, the differential power sensing technology can be used by the quadrant detector to calculate the change in the lateral displacement of the light beam; if the detector assembly uses one quadrant detector and one position-sensitive detector, the spot reading technology can be used by the position-sensitive detector to calculate the change in the lateral position. In the position-sensitive detector, the reference beam serves as the background light, and only the change in the lateral displacement of the spot of the measurement light needs to be detected to obtain the change in the lateral position of the measurement light beam. In this sub-step, the change in the lateral displacement of the corresponding light beam is obtained by calculating the detection signals at different incident angles collected within the scanning period.

[0078] Sub-step 1023: Process to obtain a lateral waveform in which the change in the lateral displacement of the light beam varies with the scanning time of the precision rotating mirror's sinusoidal scanning at multiple different incident angle conditions, and generate an analysis diagram of the change in the lateral displacement of the light beam based on multiple lateral waveforms.

[0079] It is understandable that simulation processing and analysis are performed using the change in the lateral displacement of the light beam calculated in sub-step 1021, and finally a lateral waveform in which the change in the lateral displacement of the light beam varies with the scanning time of the precision rotating mirror's sinusoidal scanning at multiple different incident angle conditions is plotted;

[0080] Among them, the lateral waveform uses the scanning time of the precision rotating mirror's sinusoidal scanning as the abscissa and the change in the lateral displacement of the light beam as the ordinate, and different lateral waveforms correspond to different incident angle conditions.

[0081] Step 103: Determine the target lateral waveform from the analysis diagram of the change in the lateral displacement of the light beam, and use the incident angle corresponding to the target lateral waveform as the target incident angle.

[0082] Specifically, the lateral waveform with the smallest amplitude of the lateral offset of the light beam can be used as the target lateral waveform, and the incident angle corresponding to the target lateral waveform is used as the target incident angle (i.e., the position where the incident angle is 45°).

[0083] Step 104: Adjust the incident angle of the measurement light beam on the reflection plane to the target incident angle, translate the laser or the precision rotating mirror to adjust the incident point position of the measurement light beam on the reflection plane, and at the same time control the precision rotating mirror to perform sinusoidal scanning rotation to obtain multiple detection signals corresponding to different incident point positions during the scanning period of the precision rotating mirror's sinusoidal scanning; based on different detection signals, an analysis diagram of the change in the longitudinal optical path of the optical path is obtained.

[0084] It is understandable that even if the incident angle is ensured to be 45°, it is still impossible to determine whether the incident light beam is incident on the optical reflection center of the precision rotating mirror. Therefore, while keeping this angle unchanged, translate the laser beam emitted by the laser or move the position of the precision rotating mirror, and observe the change in the longitudinal optical path in the longitudinal displacement change analysis diagram to confirm the position of the optical reflection center.

[0085] This step specifically includes the following sub-steps:

[0086] Sub-step 1041: Adjust the incident angle of the measurement light beam on the reflection plane to the target incident angle, translate the laser or the precision rotating mirror to adjust the incident point position of the measurement light beam on the reflection plane, and at the same time control the precision rotating mirror to perform a sinusoidal scanning rotation, so as to adjust the detection position of the measurement light beam on the detector assembly.

[0087] In this sub-step, adjust the incident angle of the measurement light beam on the reflection plane to the target incident angle (i.e., 45°). While maintaining the target incident angle, translate the laser or the precision rotating mirror, thereby changing the incident point position of the measurement light beam on the reflection plane; while adjusting the incident point position of the measurement light beam on the reflection plane, control the precision rotating mirror to perform a sinusoidal scanning rotation (such as a sinusoidal scanning rotation with an amplitude of 3 mrad).

[0088] Exemplarily, adjust the incident angle of the measurement light beam on the reflection plane to the target incident angle. At the target incident angle, taking the translation of the laser as an example: Translate the laser to the first position, and control the precision rotating mirror to perform a sinusoidal scanning rotation and complete one scanning cycle. Then continue to translate the laser to the second position, and control the precision rotating mirror to perform a sinusoidal scanning rotation and complete one scanning cycle, and so on, until the measurement light beam cannot be incident on the reflection plane.

[0089] Sub-step 1042: Based on the detection signals corresponding to different detection positions, calculate the change amount of the longitudinal optical path corresponding to different detection positions through differential wavefront sensing technology.

[0090] It is understandable that whether the detector assembly uses a four-quadrant detector, or a four-quadrant detector and a position-sensitive detector, the detection of the longitudinal optical path change is performed by the four-quadrant detector. Therefore, the change amount of the longitudinal optical path corresponding to different detection positions can be calculated through the differential wavefront sensing technology using the four-quadrant detector.

[0091] Sub-step 1043: Process to obtain the longitudinal waveform in which the change amount of the longitudinal optical path changes with the scanning time of the sinusoidal scanning rotation of the precision rotating mirror under the conditions of multiple different incident point positions, and generate an analysis diagram of the change in the longitudinal optical path based on multiple longitudinal waveforms.

[0092] Perform simulation processing and analysis using the longitudinal optical path change amount obtained by solving in sub-step 1042, and finally draw a longitudinal waveform in which the longitudinal optical path change amount changes with the scanning time of the precision rotating mirror's sinusoidal scanning rotation under multiple different incident point position conditions;

[0093] Among them, the longitudinal waveform uses the scanning time of the precision rotating mirror's sinusoidal scanning rotation as the abscissa and the longitudinal optical path change amount as the ordinate. At the same time, different longitudinal waveforms correspond to different incident point position conditions.

[0094] Step 105, determine the target longitudinal waveform from the longitudinal optical path change analysis diagram, and use the incident point position corresponding to the target longitudinal waveform as the position of the optical reflection center of the precision rotating mirror.

[0095] It should be noted that when the incident point of the measurement beam is translated to the optical reflection center, the longitudinal optical path change amount of the longitudinal waveform is the smallest and is always positive or negative with the scanning of the precision rotating mirror. At this time, the incident point position coincides with the reflection center of the precision rotating mirror.

[0096] Then, in this step, based on the longitudinal optical path change analysis diagram, the longitudinal waveform with the smallest longitudinal optical path change and whose waveform is always in the positive interval or negative interval during the sinusoidal scanning rotation of the precision rotating mirror can be used as the target longitudinal waveform; use the incident point position corresponding to the target longitudinal waveform as the position of the optical reflection center of the precision rotating mirror.

[0097] Step 106, according to the position of the optical reflection center of the precision rotating mirror, calculate the distance value between the optical reflection center and the mechanical deflection center of the precision rotating mirror, and then detect the position of the mechanical deflection center of the precision rotating mirror.

[0098] This step specifically includes the following sub-steps:

[0099] Sub-step 1061, according to the position of the optical reflection center of the precision rotating mirror, measure the distance values between the optical reflection center and the laser emission point of the laser and the center of the detector assembly respectively, and measure the included angle formed between the laser emission point of the laser and the normal of the reflection plane of the precision rotating mirror in the initial state and the included angle formed between the center of the detector assembly and the normal of the reflection plane of the precision rotating mirror in the initial state.

[0100] Sub-step 1062, control the precision rotating mirror to rotate angle, and solve the longitudinal optical path change amount and the beam lateral displacement change amount corresponding to the rotation of the precision rotating mirror angle.

[0101] Sub-step 1063, based on the preset longitudinal optical path change amount calculation formula and the beam lateral displacement change amount calculation formula, according to the measured multiple distance values, multiple included angle angles and the rotation of the precision rotating mirror Angle, rotation Based on the longitudinal optical path change and the transverse beam displacement change corresponding to the angle, the distance between the optical reflection center and the mechanical deflection center of the precision rotating mirror is calculated, and then the position of the mechanical deflection center of the precision rotating mirror is detected.

[0102] Therefore, after detecting the position of the optical reflection center, the laser exit point can be measured from the center of the reflection plane of the precision rotating mirror distance and the center of the quadrant detector from the center of the reflection plane of the precision rotating mirror distance and the incident angle , the rotation angle of the precision rotating mirror, and the angle of the detector center . According to the calculated longitudinal optical path change and the transverse beam displacement value , the distance between the rotation center and the reflection center of the precision rotating mirror can be accurately calculated , and then the position of the mechanical deflection center of the precision rotating mirror can be detected.

[0103] To further demonstrate the technical effect of the high-precision detection of the optical reflection center and the mechanical deflection center of the precision rotating mirror in the present invention, a device Figure 2 is used to detect and test the optical reflection center and the mechanical deflection center of the precision rotating mirror. Specifically:

[0104] In the process of adjusting the incident beam angle in the first step to find the position with the minimum amplitude of the transverse displacement change , taking the following parameters as an example: the transverse displacement resolution of the position-sensitive detector is 1 nm, the distance from the laser exit point to the center of the reflection plane of the precision rotating mirror , the distance from the center of the quadrant detector to the center of the reflection plane of the precision rotating mirror is 50 mm, and the minimum change interval of the incident beam angle corresponding thereto is 20 urad;

[0105] Subsequently, in the process of translating the incident beam in the second step to find the position with the minimum amplitude of the longitudinal displacement change, taking the incident beam angle having a deviation of 20 urad and the minimum resolution of the translation displacement of the incident beam being 1 nm as an example, the corresponding longitudinal displacement change is 4.24 pm. A differential wavefront sensing interferometer with a pm-level resolution can meet the measurement requirement of this displacement change;

[0106] In the third step, substitute the measured lateral displacement change value and longitudinal displacement change value into formulas (1) and (2) to inversely calculate the distance between the mechanical deflection center and the reflection center of the precision rotating mirror. , taking the following parameters as an example: there is a 20 urad deviation in the incident beam angle, a 1 nm deviation in the incident beam translation displacement, and the existing alignment accuracy is 0.1 mm. When the laser exit point and the center of the reflection plane of the precision rotating mirror point distance , the center of the quadrant detector and the center of the reflection plane of the precision rotating mirror point distance have deviations of 0.1 mm respectively, the deviation of the distance between the mechanical deflection center and the reflection center of the precision rotating mirror calculated according to the formula is 2.3 pm.

[0107] Therefore, in the present invention, the detection accuracy of the position deviation between the incident point of the light beam on the precision rotating mirror and the optical reflection center of the precision rotating mirror can reach the order of 1 nm, the incident beam angle positioning accuracy can reach the order of 20 urad, and the distance between the mechanical deflection center and the reflection center of the precision rotating mirror can reach the order of pm. It can be seen that the method of the present invention has extremely high detection accuracy for detecting the position deviation between the incident point of the light beam on the precision rotating mirror and the optical reflection center and for detecting the distance between the mechanical deflection center and the reflection center of the rotating mirror.

[0108] The present invention provides a high-precision detection and calculation method for the optical reflection center and mechanical deflection center of a precision rotating mirror. In the present invention, an optical path measurement of the light beam is realized by means of a detection device. By adjusting the direction of the laser beam emitted by the laser, and at the same time controlling the precision rotating mirror to perform a sinusoidal scanning rotation, the corresponding lateral displacement change of the light beam is calculated; then, by moving the laser or the precision rotating mirror, and at the same time controlling the precision rotating mirror to perform a sinusoidal scanning rotation, the corresponding longitudinal optical path change of the optical path is calculated, and the positions of the optical reflection center and mechanical deflection center of the precision rotating mirror are accurately detected by using the calculated longitudinal optical path change and lateral displacement change of the optical path. After detecting the positions of the optical reflection center and mechanical deflection center of the precision rotating mirror, the measurement accuracy of the optical path optical path can reach up to the order of picometers, which can effectively reduce the optical path optical path error.

[0109] Please refer to Figure 2 , the second aspect of the present invention also provides a detection device for the optical reflection center and mechanical deflection center of a precision rotating mirror. The device includes: a laser, a first beam splitter 2, a second beam splitter 4, a third beam splitter 6, a first acousto-optic modulator 3, a second acousto-optic modulator 7, a precision rotating mirror, and a detection component;

[0110] The third beam splitter 6 is configured to split the laser beam emitted by the laser into an initial reflected light beam and an initial transmitted light beam, reflect the initial reflected light beam to the first beam splitter 2, and direct the initial transmitted light beam to the second acousto-optic modulator 7;

[0111] The first beam splitter 2 is configured to reflect the initial reflected light beam to the first acousto-optic modulator 3; the first acousto-optic modulator 3 is configured to shift the frequency of the initial reflected light beam to obtain a reference light beam and direct the reference light beam to the second beam splitter;

[0112] The second acousto-optic modulator 7 is configured to shift the frequency of the initial transmitted light beam to obtain a measurement light beam and direct the measurement light beam to the precision rotating mirror; the precision rotating mirror is configured to reflect the measurement light beam to the second beam splitter 4 through the reflection plane;

[0113] The second beam splitter 4 is configured to split the reference light beam and the measurement light beam and direct the split reference light beam and measurement light beam onto the detection assembly.

[0114] In the present invention, the laser is configured to emit a laser beam with a frequency of f. After the laser beam is emitted, it is split by the third beam splitter 6 into an initial transmitted light beam and an initial reflected light beam.

[0115] The initial transmitted light beam enters the second acousto-optic modulator 7. After frequency shifting by the second acousto-optic modulator 7, a measurement light beam with a frequency of f2 is obtained. The measurement light beam is reflected by the precision rotating mirror and then split by the second beam splitter 4 into a measurement reflected light beam and a measurement transmitted light beam. In Figure 2 the measurement reflected light beam is incident on the photosensitive surface of the position-sensitive detector 9, while the measurement transmitted light beam is incident on the photosensitive surface of the quadrant detector 5.

[0116] The reference reflected light beam split by the third beam splitter 6 is reflected by the first beam splitter 2 and enters the first acousto-optic modulator 3. After frequency shifting by the first acousto-optic modulator 3, a reference light beam with a frequency of f1 is obtained. The reference light beam is also split by the second beam splitter 4 into a reference transmitted light beam and a reference reflected light beam. In Figure 2 the reference transmitted light beam is incident on the photosensitive surface of the position-sensitive detector 9, and the reference reflected light beam is incident on the photosensitive surface of the quadrant detector 5.

[0117] On the quadrant detector 5, the measurement light beam with a frequency of f2 and the reference light beam with a frequency of f1 are received simultaneously. The two light beams with different frequencies interfere, and a beat frequency signal is formed and output on the quadrant detector 5. According to this beat frequency signal, the longitudinal optical path change of the measurement light beam is calculated; on the position-sensitive detector 9, the measurement light beam with a frequency of f2 and the reference light beam with a frequency of f1 are also received simultaneously. The coherent detection is used for the output of the position-sensitive detector 9 by using the spot reading technique, and the lateral displacement change of the measurement light beam with a frequency of f2 on the position-sensitive detector 9 is calculated.

[0118] It should be noted that the detector component can be selected according to actual test requirements. The measurement range of the solution using only one quadrant detector is smaller than that of the solution using one quadrant detector and a position sensitive detector. However, it can save the number of detectors, detection costs, and detection space, and reduce the complexity of data processing and measurement procedures.

[0119] The detection device provided by the present invention can perform complex and precise optical path measurements. Multiple beam splitters can accurately separate and guide light beams. Different acousto-optic modulators can be used to modulate the frequency of light beams, thereby providing two light beams with different frequencies (measurement light beam and reference light beam). By using different light beams and modulation methods, when the precision rotating mirror performs a sinusoidal scanning rotation, the optical path change of the measurement light can be accurately detected using the optical path of the reference light beam, and then the longitudinal optical path change and the lateral position change of the light beam corresponding to the measurement light beam can be accurately calculated, improving the detection accuracy of the positions of the optical reflection center and the mechanical deflection center of the precision rotating mirror.

[0120] Those skilled in the art can clearly understand that for the convenience and brevity of description, the specific working processes of the above-described systems, devices, and units can refer to the corresponding processes in the foregoing method embodiments and will not be elaborated herein.

[0121] In several embodiments provided in the present application, it should be understood that the disclosed systems, devices, and methods can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For example, the division of the units is only a logical function division, and there can be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the displayed or discussed couplings or direct couplings or communication connections to each other can be indirect couplings or communication connections through some interfaces, devices, or units, and can be in electrical, mechanical, or other forms.

[0122] The units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they can be located in one place or distributed to multiple network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0123] In addition, in each embodiment of the present invention, the functional units can be integrated into one processing unit, or each unit can exist physically alone, or two or more units can be integrated into one unit. The above integrated units can be implemented in the form of hardware or in the form of software functional units.

[0124] When the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The foregoing storage medium includes: various media such as USB flash drives, mobile hard disks, read-only memories (ROMs), random access memories (RAMs), magnetic disks, or optical discs that can store program codes.

[0125] As described above, the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments or perform equivalent replacements for some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A high-precision detection and calculation method for the optical reflection and mechanical deflection center of a precision rotating mirror, characterized in that: The method comprises: The laser beam is emitted by a laser, and the laser beam is split into a measuring beam and a reference beam; the measuring beam is emitted to a precision rotating mirror, and the measuring beam is reflected by the reflection plane of the precision rotating mirror to a detector assembly, and the reference beam is incident on the detector assembly at the same time, so that the measuring beam and the reference beam perform beam interference on the detector assembly to generate a detection signal; The emission direction of the laser beam of the laser is adjusted to adjust the incident angle of the measuring beam incident on the reflection plane, and the precision rotating mirror is controlled to perform sinusoidal scanning rotation, so as to obtain a plurality of detection signals corresponding to different incident angles during the scanning period of the precision rotating mirror performing sinusoidal scanning rotation; and an analysis diagram of the lateral displacement change of the light beam is obtained based on the processing of different detection signals; Determine a target transverse waveform from the light beam transverse displacement change analysis diagram, and use the incident angle corresponding to the target transverse waveform as the target incident angle; The incident angle of the measuring light beam incident on the reflecting plane is adjusted to the target incident angle, the laser or the precision rotating mirror is translated to adjust the incident point position of the measuring light beam incident on the reflecting plane, and the precision rotating mirror is controlled to perform sinusoidal scanning rotation at the same time, so as to obtain a plurality of detection signals corresponding to different incident point positions during the scanning period of the precision rotating mirror performing sinusoidal scanning rotation; and an analysis diagram of the longitudinal optical path change of the optical path is obtained based on the processing of different detection signals; Determine the target longitudinal waveform from the optical path longitudinal optical path change analysis diagram, and use the incident point position corresponding to the target longitudinal waveform as the position of the optical reflection center of the precision rotating mirror; According to the position of the optical reflection center of the precision rotating mirror, the distance value between the optical reflection center of the precision rotating mirror and the mechanical deflection center is calculated, and then the position of the mechanical deflection center of the precision rotating mirror is detected.

2. The high-precision detection and calculation method of the optical reflection and mechanical deflection center of the precision rotating mirror according to claim 1 is characterized in that: The output direction of the laser beam of the laser is adjusted to adjust the incident angle of the measuring beam incident on the reflection plane, and at the same time, the precision mirror is controlled to perform sinusoidal scanning rotation to obtain a plurality of detection signals corresponding to different incident angles during the scanning period of the precision mirror performing sinusoidal scanning rotation; The steps of obtaining a beam lateral displacement change analysis diagram based on different detection signal processing include: Adjusting the emission direction of the laser beam of the laser to adjust the incident angle of the measuring beam incident on the reflection plane, and controlling the precision mirror to perform sinusoidal scanning rotation, thereby adjusting the detection position of the measuring beam incident on the detector assembly; Based on the detection signals corresponding to different detection positions, the changes in the lateral displacement of the light beam corresponding to different detection positions are calculated by using differential power sensing technology or light spot reading technology; The lateral waveforms of the change in the lateral displacement of the light beam under multiple different incident angles as the scanning time of the sinusoidal scanning rotation of the precision rotating mirror are obtained by processing, and an analysis diagram of the change in the lateral displacement of the light beam is generated based on the multiple lateral waveforms.

3. The high-precision detection and calculation method of the optical reflection and mechanical deflection center of the precision rotating mirror according to claim 2 is characterized in that: The step of determining the target lateral waveform from the light beam lateral displacement change analysis diagram and taking the incident angle corresponding to the target lateral waveform as the target incident angle includes: based on the light beam lateral displacement change analysis diagram, taking the lateral waveform with the smallest lateral offset amplitude of the light beam as the target lateral waveform; and taking the incident angle corresponding to the target lateral waveform as the target incident angle.

4. The high-precision detection and calculation method of the optical reflection and mechanical deflection center of the precision rotating mirror according to claim 1 is characterized in that: The incident angle of the measuring beam incident on the reflecting plane is adjusted to the target incident angle, the laser or the precision rotating mirror is translated to adjust the incident point position of the measuring beam incident on the reflecting plane, and the precision rotating mirror is controlled to perform sinusoidal scanning rotation at the same time, so as to obtain a plurality of detection signals corresponding to different incident point positions during the scanning period of the precision rotating mirror performing sinusoidal scanning rotation; The steps of obtaining the optical path longitudinal optical path change analysis diagram based on different detection signal processing include: The incident angle of the measuring beam incident on the reflection plane is adjusted to the target incident angle, the laser or the precision rotating mirror is translated to adjust the incident point position of the measuring beam incident on the reflection plane, and the precision rotating mirror is controlled to perform sinusoidal scanning rotation, so as to adjust the detection position of the measuring beam incident on the detector assembly; Based on the detection signals corresponding to different detection positions, the longitudinal optical path change corresponding to different detection positions is calculated by differential wavefront sensing technology; The longitudinal waveforms of the change in the longitudinal optical path length under multiple different incident point position conditions as the scanning time of the sinusoidal scanning rotation of the precision rotating mirror are obtained by processing, and an analysis diagram of the longitudinal optical path length change of the optical path is generated based on the multiple longitudinal waveforms.

5. The high-precision detection and calculation method of the optical reflection and mechanical deflection center of the precision rotating mirror according to claim 4 is characterized in that: The step of determining the target longitudinal waveform from the longitudinal optical path change analysis diagram of the optical path, and taking the incident point position corresponding to the target longitudinal waveform as the position of the optical reflection center of the precision rotating mirror, comprises: based on the longitudinal optical path change analysis diagram of the optical path, taking the longitudinal waveform with the smallest longitudinal optical path change and the waveform always being in the positive interval or the negative interval during the sinusoidal scanning rotation of the precision rotating mirror as the target longitudinal waveform; taking the incident point position corresponding to the target longitudinal waveform as the position of the optical reflection center of the precision rotating mirror.

6. The high-precision detection and calculation method of the optical reflection and mechanical deflection center of the precision rotating mirror according to claim 1 is characterized in that: The step of calculating the distance between the optical reflection center of the precision rotating mirror and the mechanical deflection center according to the position of the optical reflection center of the precision rotating mirror, and then detecting the position of the mechanical deflection center of the precision rotating mirror comprises: According to the position of the optical reflection center of the precision rotating mirror, the distance values ​​between the optical reflection center and the laser emission point of the laser and the center of the detector assembly are measured, and the angle formed between the laser emission point of the laser and the normal line of the reflection plane of the precision rotating mirror in the initial state and the angle formed between the center of the detector assembly and the normal line of the reflection plane of the precision rotating mirror in the initial state are measured; Control the rotation of precision mirror Angle, solve the precision mirror rotation The change in the longitudinal optical path and the transverse displacement of the light beam corresponding to the angle; Based on the preset calculation formula for the longitudinal optical path change and the calculation formula for the transverse displacement change of the light beam, according to the measured multiple distance values, multiple angles and the rotation of the precision mirror Angle, rotation The longitudinal optical path change and the lateral displacement change of the light beam corresponding to the angle are used to calculate the distance between the optical reflection center and the mechanical deflection center of the precision rotating mirror, and then the position of the mechanical deflection center of the precision rotating mirror is detected.

7. The high-precision detection and calculation method of the optical reflection and mechanical deflection center of the precision rotating mirror according to claim 6 is characterized in that: The preset calculation formula for the longitudinal optical path change is as follows: Where: Indicates the distance between the laser emission point of the laser and the optical reflection center of the precision mirror. Indicates the distance between the optical reflection center and the mechanical deflection center of the precision mirror. Indicates the distance between the center of the detector assembly and the optical reflection center of the precision rotating mirror; It indicates the angle at which the direction of the laser beam emitted by the laser deviates from the ideal light. It represents the angle between the laser emission point of the laser and the normal line of the reflection plane of the precision rotating mirror in the initial state. It represents the angle formed between the center of the detector assembly and the normal line of the reflection plane of the precision rotating mirror in the initial state; Indicates that the precision mirror rotates The change of the longitudinal optical path of the optical path obtained by solving the angle; The preset calculation formula for the change in beam lateral displacement is as follows: Where: Indicates that the precision mirror rotates The change in the lateral displacement of the light beam obtained by solving the angle.

8. A device for detecting the optical reflection center and mechanical deflection center of a precision rotating mirror, characterized in that: The device comprises: a laser, a first spectroscope, a second spectroscope, a third spectroscope, a first acousto-optic modulator, a second acousto-optic modulator, a precision rotating mirror and a detector assembly; The third beam splitter is used to split the laser beam emitted by the laser into an initial reflected light beam and an initial transmitted light beam, reflect the initial reflected light beam to the first beam splitter, and emit the initial transmitted light beam to the second acousto-optic modulator; The first beam splitter is used to reflect the initial reflected light to the first acousto-optic modulator; the first acousto-optic modulator is used to frequency-shift the initial reflected light to obtain a reference beam, and emit the reference beam to the second beam splitter; The second acousto-optic modulator is used to shift the frequency of the initial transmitted light to obtain a measuring beam, and to direct the measuring beam toward the precision rotating mirror; the precision rotating mirror is used to reflect the measuring beam toward the second spectroscope through a reflecting plane; The second beam splitter is used to split the reference beam and the measurement beam, and direct the split reference beam and measurement beam to the detection component.

9. The detection device for the optical reflection center and the mechanical deflection center of the precision rotating mirror according to claim 8, characterized in that: The detector assembly specifically adopts a four-quadrant detector; The second beam splitter is specifically used to split the reference beam into a reference transmitted light and a reference reflected light, split the measuring beam into a measuring transmitted light and a measuring reflected light, and direct the reference reflected light and the measuring transmitted light to the four-quadrant detector.

10. The detection device for the optical reflection center and the mechanical deflection center of the precision rotating mirror according to claim 8, characterized in that: The detector assembly specifically consists of a four-quadrant detector and a position sensitive detector; The second spectroscope is specifically used to split the reference light beam into a reference transmitted light beam and a reference reflected light beam, split the measuring light beam into a measuring transmitted light beam and a measuring reflected light beam, and direct the reference reflected light and the measuring transmitted light beam to the four-quadrant detector and direct the reference transmitted light and the measuring reflected light beam to the position sensitive detector.

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