WO2023015933A1 - 一种激光位移测量装置和方法 - Google Patents
一种激光位移测量装置和方法 Download PDFInfo
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B11/00—Measuring arrangements characterised by the use of optical techniques
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B9/00—Measuring instruments characterised by the use of optical techniques
- G01B9/02—Interferometers
- G01B9/02055—Reduction or prevention of errors; Testing; Calibration
Definitions
- the invention belongs to the technical field of precision measurement, in particular to a laser displacement measurement device and method based on optical vernier Fabry-Perot interferometry.
- High-precision nano-displacement measurement has important applications in technical fields such as ultra-precision machining, microelectronics manufacturing, and precision testing and measurement.
- the laser interferometer takes the wavelength of light as the measurement scale and has ultra-high resolution measurement capability. It is one of the most precise measuring instruments in the field of measurement and has been widely used in the field of modern industrial measurement. However, whether it is a single-frequency laser interferometer or a dual-frequency laser interferometer, there are periodic nonlinear errors. These nonlinear errors can reach several nanometers, or even tens of nanometers, which seriously affects the improvement of the accuracy of the laser interferometer. .
- the resolution or measurement range of the interferometry will be limited to a certain extent when performing large-scale measurements, and both cannot be considered.
- the object of the present invention is to provide a laser displacement measurement device and method, and simultaneously build two sets of Fabry-Perot interferometers to coordinate with each other to form the main and auxiliary measurement interference signals, and to understand and call out the displacement measurement through the principle of optical vernier. Large and small numbers, to achieve dynamic displacement measurement with sub-picometer resolution in a large range.
- the present invention adopts the following technical solutions:
- a laser displacement measuring device comprising: an interferometric module, a laser light source module, a signal modulation module, a control processing module, and an optical cursor demodulation module; wherein, the control processing module controls the signal modulation module to apply a light source modulation signal to the laser light source module, so that The laser light source module provides two beams of laser beams with fixed frequency difference to the interferometry module; the control processing module controls the interferometry module to perform interferometry, and the lasers are respectively interfered in two Fabry-Perot cavities in the interferometry module and are respectively received by the two The primary and secondary measurement interference signals are formed by detection by photoelectric detectors; the optical cursor demodulation module demodulates the primary and secondary measurement interference signals obtained by the interferometric measurement module, and the demodulation result is calculated by the control processing module to obtain the measured displacement.
- the interferometric module includes: a first photodetector, a second photodetector, a first precision displacement stage, a first resonant plane mirror, a second resonant plane mirror, a first corner cone reflector, a second precision displacement platform; wherein, the laser light source module emits the main laser beam and the auxiliary laser beam; the main laser beam enters and is reflected by the first resonant plane mirror fixed on the first precision translation platform and the first pyramid fixed on the second precision translation platform
- the first Fabry-Perot cavity formed by the mirror is interfered to form the main measurement interference beam, and the main measurement interference beam is received by the first photodetector to form the main measurement interference signal; Interference is performed in the second Fabry-Perot cavity formed by the mirror to form a secondary measurement interference beam, and the secondary measurement interference beam is received by the second photodetector to form a secondary measurement interference signal.
- the laser light source module emits two main laser beams and auxiliary laser beams with a fixed frequency difference; the main laser beam is divided into the first sub-main laser beam by the beam splitter beam and the second sub-main laser beam; the first sub-main laser beam is reflected into the mirror composed of the third resonant plane mirror fixed on the first precision translation stage and the first corner cone mirror fixed on the second precision translation stage Interference is performed in the first Fabry-Perot cavity to form the first sub-main measurement interference beam, and the first sub-main measurement interference beam is transmitted by the spectroscope and then received by the first photodetector to form the first sub-main measurement interference signal;
- the first resonant plane mirror is a plane mirror with a first reflectivity at both ends, and the first reflectivity is 2.5% to 97.6%; the second resonant plane mirror is fully transparent in the middle and has a second reflectivity at both ends. In the plane mirror with two reflectivity, the second reflectivity is 2.5%-97.6%.
- the second resonant plane mirror is a plane mirror with total transmission in the middle and a second reflectivity at both ends, and the second reflectivity is 2.5% to 97.6%;
- the third resonant plane mirror is a plane mirror with a third
- the third reflectivity is 90%-97.6%, and the fourth reflectivity is 2.5%-97.6%.
- the present invention also provides a laser displacement measurement method, comprising the following steps:
- Step 1 the signal modulation module modulates the laser light source module so that it emits two beams of laser light with wavelengths of ⁇ and ⁇ 0 and enters the interferometry module for interferometry;
- Step 2 the control processing module controls the interferometry module to perform interferometry; the laser beams with wavelengths of ⁇ and ⁇ 0 are respectively directed to the first precision displacement stage, the first resonant flat mirror, the first corner mirror and the second precision displacement stage.
- the main Fabry-Perot interferometer and the secondary Fabry-Perot interferometer composed of the second resonant plane mirror, the first corner mirror and the second precision displacement stage are interfered to form the main measurement interference beam and the secondary measurement interference beam, and then respectively Received by the first and second photodetectors;
- Step 3 the control processing module controls the movement of the second precision translation stage, so that the first pyramid mirror scans back and forth;
- Step 4 when the first resonant plane mirror moves displacement ⁇ L, the main measurement interference beam is detected by the first photodetector to obtain the main measurement interference signal; the secondary measurement interference beam is detected by the second photodetector to obtain the secondary measurement interference signal; the optical cursor
- the demodulation module demodulates the main measurement interference signal and the auxiliary measurement interference signal through the principle of optical cursors, and the number M of displacement decimals is demodulated, and the displacement decimal l is calculated by the control processing module:
- Step 5 When the displacement of the second resonant plane mirror exceeds a Fabry-Perot interference peak, that is, the displacement exceeds a large number, the optical cursor demodulation module demodulates the displacement number N, and the displacement is calculated by the control processing module.
- Number L
- Step 6 The control processing module obtains the measured displacement ⁇ L by calculating the large displacement and the decimal displacement according to the following formula,
- the first resonant plane mirror is a plane mirror with a first reflectivity at both ends, and the first reflectivity is 2.5% to 97.6%; the second resonant plane mirror is fully transparent in the middle and has a second reflectivity at both ends. In the plane mirror with two reflectivity, the second reflectivity is 2.5%-97.6%.
- the present invention also provides a laser displacement measurement method, comprising the following steps:
- Step 1 the signal modulation module modulates the laser light source module so that it emits two beams of laser light with wavelengths of ⁇ and ⁇ 0 and enters the interferometry module for interferometry;
- Step 2 the control processing module controls the interferometry module to perform interferometry; the laser with a wavelength of ⁇ is divided into the first sub-main laser beam and the second sub-main laser beam by the beam splitter, the first sub-main laser beam, the first sub-main laser beam
- the laser beam with wavelength ⁇ 0 shoots to the first main Fabry-Perot interferometer composed of the first precision displacement stage, the third resonant plane mirror, the first corner cone reflector and the second precision displacement stage respectively, and the first precision displacement stage , the second main Fabry-Perot interferometer composed of the third resonant plane mirror and the second corner mirror and the secondary Fabry-Perot interferometer composed of the second resonant plane mirror, the first corner mirror and the second precision translation stage Interfering to form the first sub-main measurement interference beam, the second sub-main measurement interference beam and the sub-measurement interference beam, and then received by the first, second and third photodetectors respectively;
- Step 3 the control processing module controls the movement of the second precision translation stage, so that the first pyramid mirror scans back and forth;
- Step 4 When the third resonant plane mirror is displaced by ⁇ L, the first sub-main measurement interference beam is detected by the first photodetector to obtain the first sub-main measurement interference signal; the sub-main measurement interference beam is detected by the second photodetector to obtain the sub-main measurement interference beam. Measuring the interference signal; detecting the second sub-main measurement interference beam by the third photodetector to obtain the second sub-main measurement interference signal;
- Step 5 the optical cursor demodulation module demodulates the first sub-main measurement interference signal and the secondary measurement interference signal through the principle of the optical cursor, demodulates the number of displacement decimals M, and calculates the displacement decimal l by the control processing module:
- Step 6 The optical cursor demodulation module demodulates the second sub-main measurement interference signal to obtain a large number of displacements, which is calculated by the control processing module to obtain a large number of displacements L:
- Step 7 The control processing module obtains the measured displacement ⁇ L by calculating the large number of displacements and the decimal number of displacements according to the following formula,
- the second resonant plane mirror is a plane mirror with total transmission in the middle and a second reflectivity at both ends, and the second reflectivity is 2.5% to 97.6%;
- the third resonant plane mirror is a plane mirror with a third
- the third reflectivity is 90%-97.6%, and the fourth reflectivity is 2.5%-97.6%.
- the Fabry-Perot interferometer adopted in the present invention realizes the combination of displacement measurement and displacement, which can overcome the problems that the Fabry-Perot cavity cannot meet long-distance interferometric measurement.
- the present invention adopts a dual-frequency dual-Fabry-Perot cavity structure, which has strong anti-interference ability and can realize long-distance and high-precision measurement.
- Fig. 1 is the working principle diagram of the laser displacement measuring device of the present invention
- Fig. 2 is a schematic diagram of the optical principle of the interferometry module of the present invention.
- Fig. 3 is a schematic diagram of the optical principle of another structure of the interferometric module of the present invention.
- Figure 4 is a signal diagram of interference peaks formed by Fabry-Perot interference at different wavelengths
- Interferometry module 2. Laser light source module, 3. Signal modulation module, 4. Control processing module, 5. Optical cursor demodulation module, 6. First photodetector, 7. Second photodetector , 8, the first precision translation stage, 9, the first resonant plane mirror, 10, the second resonant plane mirror, 11, the first corner mirror, 12, the second precision translation stage, 13, the second corner mirror, 14 .
- the third resonant plane mirror 15. Reflector, 16. Beam splitter, 17.
- the third photodetector 18. Beam splitter.
- the vernier effect was originally used to improve the resolution of length measurement (such as a vernier caliper). Its working principle is to use the small scale difference between the main ruler and the vernier to measure the length.
- the principle of the optical vernier is the application of the vernier effect in optical interference.
- two lasers with wavelength differences perform Fabry-Perot interference
- two interference signals with small differences will be formed, which is similar to the main ruler and vernier of a vernier caliper. .
- displacement readings with sub-picometer resolution can be obtained through the optical vernier and the optical main scale.
- Fabry-Perot interference is multi-beam interference, according to the formula of multi-beam interference:
- I is the intensity of the transmitted light
- a is the amplitude of the incident light
- R is the light intensity reflectance of the Fabry-Perot cavity resonator
- d is the length of the Fabry-Perot cavity
- ⁇ is the wavelength of the incident light.
- interference peaks with different spacing will appear as the Fabry-Perot cavity changes. If the interference wavelengths of two Fabry-Perot cavities are very close, then the intervals between the interference peaks formed by their respective interferences will also be very close. For example, the difference between the interference peak intervals formed by the interference between the wavelength of 633nm and the wavelength of 632.996nm is 1pm.
- the optical main scale and the optical vernier can be constructed by using these two interference peaks with different equal intervals, and the optical vernier with different resolutions can be formed according to different wavelength differences.
- the present invention provides a kind of laser displacement measurement device comprising: interferometric module 1, laser light source module 2, signal modulation module 3, control processing module 4, optical vernier demodulation module 5 composition; Said signal modulation module 3. Modulate the laser light of the laser light source module 2, so that the laser light source module 2 provides the interferometric module 1 with two laser beams with a fixed frequency difference.
- the control processing module 4 controls the interferometric module 1 to perform interferometric measurement.
- the optical vernier demodulation module 2 demodulates the interference signal obtained by the interferometric measurement module 1, and the demodulation result is calculated by the control processing module 4 to obtain the measured displacement;
- the interferometric module 1 includes a first photodetector 6, a second photodetector 7, a first precision translation stage 8, a first resonant plane mirror 9, a second resonant plane mirror 10, a first angle Cone reflector 11, second precision displacement stage 12; laser light source module 2 emits two laser beams, the main laser beam and the auxiliary laser beam; the main laser beam enters the first resonant plane mirror 9 fixed on the first precision displacement stage 8 It interferes with the first Fabry-Perot cavity formed by the first corner mirror 11 fixed on the second precision displacement stage 12 to form the main measurement interference beam, and the main measurement interference beam is received by the first photodetector 6 to form the main measurement interference signal.
- the secondary laser beam enters into the second Fabry-Perot cavity formed by the second resonant plane mirror 10 and the first corner mirror 11 for interference to form a secondary measurement interference beam.
- the secondary measurement interference beam is received by the second photodetector 7 to form a secondary measurement interference signal.
- the interferometer composed of the first precision translation stage 8, the first resonant plane mirror 9, the first pyramid reflector 11 and the second precision translation platform 12 is the main Fabry-Perot interferometer, the second resonant plane mirror 10, the first pyramid
- the interferometer composed of the mirror 11 and the second precision displacement stage 12 is a secondary Fabry-Perot interferometer; the second Fabry-Perot cavity composed of the second resonant plane mirror 10 and the first corner mirror 11 is the main Fabry-Perot interferometer The common cavity of the instrument and the secondary Fabry-Perot interferometer.
- Two sets of interferometers are thus formed.
- the first pyramid reflector 11 scans back and forth to form an optical cursor, and the displacement of the first resonant plane mirror 9 can be accurately calculated by combining large and small numbers. .
- the first resonant plane mirror is a plane mirror with a first reflectivity at both ends, and the first reflectivity is 2.5% to 97.6%;
- the second resonant plane mirror is fully transmissive in the middle and has a second reflectivity at both ends.
- the second reflectivity is 2.5%-97.6%.
- the present invention also provides a laser displacement measurement method, the implementation process is as follows:
- the signal modulation module 3 controlled by the control processing module 4 applies a light source modulation signal to the laser light source module 2, so that the laser light source module 2 emits two beams of laser light with wavelengths ⁇ 0 and ⁇ 1 to enter the interferometric module 1 for measurement.
- the main measurement interference signal and the auxiliary measurement interference signal are obtained by interference.
- the length of the optical vernier at this time is the length between the two alignment positions of the optical main scale and the optical sub scale, which is:
- the main and auxiliary measurement interference signals are sent to the optical cursor demodulation module 5 at the same time, and the optical cursor demodulation module 5 demodulates and judges the main and auxiliary measurement interference signals, and judges whether the main and auxiliary measurement interference signals reach the interference peak at the same time.
- the optical vernier demodulation module 5 sends a signal that the zero point is not detected to the control processing module 4, and the control processing module 4 controls the interferometric measurement module 1 after receiving the zero point signal that is not detected
- the second precision translation stage 12 in the center moves, and the first corner mirror 11 fixed on it moves.
- the optical vernier demodulation module 5 demodulates and judges the main and auxiliary measurement interference signals, and judges whether they reach the interference signal at the same time. After the peak point is judged, the judgment result is sent to the control processing module 4 .
- the control processing module 4 controls the second precision translation platform 12 to stop moving, and records the position L 0 of the second precision translation platform 12 at this time.
- the main and auxiliary measurement interference signals formed by the interferometric module 1 all reach the interference peak point, thereby realizing the mechanical zeroing of the device of the present invention.
- control processing module 4 controls the movement of the first precision translation stage 8, so that the first resonant plane mirror 9 fixed on it moves with a step value smaller than the peak interval of the main measurement interference signal, and after each step stops, the control processing The module 4 controls the second precision translation stage 12 to scan an optical vernier length ly from the position L 0 to the moving direction of the first resonant plane mirror 9 , so that the first corner mirror 11 scans an optical vernier length ly .
- the main and auxiliary measurement interference signals are simultaneously sent to the optical cursor demodulation module 5 for demodulation and judgment, and it is judged whether the main and auxiliary measurement interference signals reach the interference peak at the same time.
- the number of interference peaks passed by the secondary measurement interference signal is counted at the same time, that is, the displacement decimals are counted.
- the optical cursor demodulation module 5 sends the signal that the main and auxiliary measurement interference signals reach the interference peak point at the same time and the signal of the number M of interference peaks that the auxiliary measurement interference signal passes through to the control processing module 4 , the control processing module 4 controls the first corner mirror 11 to stop scanning and return to the position L0 .
- calculate the displacement decimal l according to the formula (4):
- the control Processing module 4 draws displacement large number N by analogy, calculates and obtains displacement large number by formula (5):
- control processing module 4 calculates the measured displacement ⁇ L according to the formula (6), and then performs the next displacement measurement.
- the interferometric measurement module adopts the device in schematic diagram 3 .
- the interferometric module 1 adds a Fabry-Perot interferometer consisting of a first precision displacement stage, a third resonant plane mirror, and a second corner mirror on the basis of the interferometric device in Figure 2,
- the second resonant plane mirror 10 is used to replace the first resonant plane mirror 9 . It specifically includes a first photodetector 6, a second photodetector 7, a first precision translation stage 8, a second resonant plane mirror 10, a first corner cone mirror 11, a second precision translation stage 12, and a second corner cone reflector. 13.
- the beam is split into two laser beams by the beam splitter 15, namely the first sub-main laser beam and the first sub-main laser beam.
- the first sub-main laser beam is reflected into the first Fabry-Perot composed of the third resonant plane mirror 14 fixed on the first precision displacement stage 8 and the first corner mirror 11 fixed on the second precision displacement stage 12.
- Interference is carried out in the cavity to form a first sub-main measurement interference beam
- the first sub-main measurement interference beam is transmitted through the beam splitter 17 and then received by the first photodetector 6 to form a first sub-main measurement interference signal.
- the second sub-main laser beam is reflected into the second Fabry-Perot cavity formed by the third resonant plane mirror 14 and the second corner mirror 13 to interfere to form the second sub-main measurement interference beam
- the second sub-main measurement interference beam After being reflected by the beam splitter 18, it is received by the third photodetector 17 to form the second sub-main measurement interference signal.
- the first sub-main measurement interference signal and the second sub-main measurement interference signal constitute the main measurement interference signal.
- the secondary laser beam is reflected by the mirror 15 into the third Fabry-Perot cavity formed by the second resonant plane mirror 10 and the first corner mirror 11 to interfere to form a secondary measurement interference beam, and the secondary measurement interference beam is captured by the second photodetector 7. Receive and form the secondary measurement interference signal.
- the second resonant plane mirror is a plane mirror with full transmission in the middle and a second reflectivity at both ends, and the second reflectivity is 2.5% to 97.6%;
- the third resonant plane mirror has a third reflection in the middle rate and has a fourth reflectivity at both ends, the third reflectivity is 90%-97.6%, and the fourth reflectivity is 2.5%-97.6%.
- the present invention also provides a laser displacement measurement method, the implementation process is as follows:
- the signal modulation module 3 controlled by the control processing module 4 applies a light source modulation signal to the laser light source module 2, so that the laser light source module 2 emits two beams of laser light with wavelengths ⁇ 0 and ⁇ 1 to enter the interferometric module 1 for measurement.
- Interference obtains the first sub-main measurement interference signal I 0 , the second sub-main measurement interference signal I 1 , and the sub-measurement interference signal I 2 , and the length of the optical cursor at this time is That is, the length between the two alignment positions of the optical main scale and the optical sub scale.
- the measurement interference signals I 0 , I 1 , and I 2 are sent to the optical cursor demodulation module 5 at the same time, and the optical cursor demodulation module 5 demodulates and judges the measurement interference signals I 0 , I 1 , and I 2 to judge the measurement interference signals Whether I 0 and I 2 reach the interference peak point at the same time.
- the optical cursor demodulation module 5 sends a signal that the zero point is not detected to the control processing module 4, and after the control processing module 4 receives the zero point signal that is not detected, control
- the second precision translation stage 12 in the interferometric module 1 moves, and the first corner mirror 11 fixed on it moves.
- the optical vernier demodulation module 5 demodulates and judges the measurement interference signals I 0 and I 2 , judging whether it reaches the interference peak point at the same time, and sending the judging result to the control processing module 4 after judging.
- the control processing module 4 controls the second precision translation platform 12 to stop moving, and records the position L 0 of the second precision translation platform 12 at this time.
- the control processing module 4 controls the movement of the first precision translation stage 8, so that the third resonant plane mirror 14 fixed on it moves, and in this process, the optical vernier demodulation module 5 demodulates and judges the second sub-main measurement interference signal, when When the second sub-main measurement interference signal reaches the first interference peak, the control processing module 4 controls the first precision translation stage 8 to stop moving.
- the control processing module 4 controls the second precision translation stage 12 to scan an optical vernier length ly from the position L 0 to the moving direction of the third resonant plane mirror 14, so that the first pyramid mirror 11 scans an optical vernier length ly .
- the optical vernier demodulation module 5 demodulates and judges the measurement interference signals I 0 and I 2 , and judges whether the measurement interference signals I 0 and I 2 reach the interference peak point at the same time. During the judging process, the number of interference peaks passed by the secondary measurement interference signal I 2 is counted at the same time, that is, the displacement decimals are counted.
- the optical cursor demodulation module 5 When the measurement interference signals I 0 and I 2 reach the interference peak point at the same time, the optical cursor demodulation module 5 will The signal of the measured interference signal I 0 and I 2 reaching the interference peak point at the same time and the signal of the number M of the interference peaks passed by the secondary measurement interference signal I 2 are sent to the control processing module 4, and the control processing module 4 calculates the displacement by formula (4) Decimal, and remember the displacement decimal l 0 demodulated at this time. The control processing module 4 controls the second precision translation stage 12 to return to the position L0 .
- the measurement interference signals I 0 and I 2 formed by the interferometric measurement module 1 both reach the interference peak point, thereby realizing the mechanical zeroing of the device of the present invention.
- control processing module 4 controls the movement of the first precision translation stage 8, so that the third resonant plane mirror 14 fixed thereon moves, and in this process, the optical vernier demodulation module 5 passes through the second sub-main measurement interference signal I 1 Count the number N of interference peaks, that is, count the large number of displacements.
- control processing module 4 controls the second precision translation stage 12 to repeatedly scan an optical cursor length ly from the position L 0 to the moving direction of the third resonant plane mirror 14 , so that the first corner mirror 11 Scan an optical cursor length ly .
- the optical vernier demodulation module 5 demodulates and judges the measurement interference signals I 0 and I 2 , and judges whether the measurement interference signals I 0 and I 2 reach the interference peak point at the same time. During the judging process, the number of interference peaks passed by the secondary measurement interference signal I 2 is counted at the same time, that is, the displacement decimals are counted.
- the optical cursor demodulation module 5 When the measurement interference signals I 0 and I 2 reach the interference peak point at the same time, the optical cursor demodulation module 5 will The signal of the measurement interference signal I 0 and I 2 arriving at the interference peak point at the same time, the signal of the number of interference peaks M passed by the secondary measurement interference signal I 2 and the signal of the number N of interference peaks passed by the second sub-main measurement interference signal I 1 are sent To the control processing module 4, the control processing module 4 calculates the decimal number of displacement through the formula (4), and obtains the large number of displacement through the calculation of the formula (5).
- the final measured displacement is given by the following rules:
- the final measured displacement is the displacement fraction:
- l0 is not zero, which means that at the starting point of scanning of the first corner mirror 11, the second sub-main measurement interference signal is not at the position of the interference peak.
- l0 is zero, representing the position of the scanning starting point of the first corner mirror 11, the position of the second sub-main measurement interference signal at the interference peak, at this time:
- the measured displacement ⁇ L is finally calculated, and then the next measurement is performed.
Abstract
一种激光位移测量装置和方法，包括：干涉测量模块（1）、激光光源模块（2）、信号调制模块（3）、控制处理模块（4）、光学游标解调模块（5）；其中，控制处理模块（4）控制信号调制模块（3）给激光光源模块（2）施加光源调制信号，使得激光光源模块（2）提供给干涉测量模块（1）两束固定频差的激光；控制处理模块（4）控制干涉测量模块（1）进行干涉测量，测量时激光在干涉测量模块（1）中的两个Fabry-Perot腔内分别进行干涉并分别被两个光电探测器探测形成主副测量干涉信号；光学游标解调模块（5）对干涉测量模块（1）得到的主副测量干涉信号进行解调，解调结果通过控制处理模块（4）计算得到被测位移。构建两套Fabry-Perot干涉仪相互协调，形成主副测量干涉信号，通过光学游标原理解调出位移测量的大小数，实现大量程亚皮米级分辨力动态位移测量。
Description
本发明属于精密测量技术领域，特别是涉及一种基于光学游标Fabry-Perot干涉术的激光位移测量装置和方法。
高精度的纳米位移测量在超精密加工、微电子制造以及精密测试计量等技术领域有着重要的应用。激光干涉仪以光波长为测量尺度，具有超高分辨率的测量能力，是测量领域中最精密的测量仪器之一，在现代工业测量领域得到了广泛的应用。然而不管是单频激光干涉仪还是双频激光干涉仪，都存在着周期性的非线性误差，这些非线性误差可以达到几纳米，甚至可以达到几十纳米，严重影响了激光干涉仪精度的提升。同时激光干涉方法由于受到干涉激光波长以及光学结构等的影响，在进行大量程测量时，其干涉测量的分辨力或测量范围会受到一定的限制，不能二者兼顾。
发明内容
针对现有技术中的不足，本发明的目的在于提供激光位移测量装置和方法，同时构建两套Fabry-Perot干涉仪相互协调，形成主副测量干涉信号，通过光学游标原理解调出位移测量的大小数，实现大量程亚皮米级分辨力动态位移测量。
为实现上述目的，本发明采用如下的技术方案：
一种激光位移测量装置，包括：干涉测量模块、激光光源模块、信号调制模块、控制处理模块、光学游标解调模块；其中，控制处理 模块控制信号调制模块给激光光源模块施加光源调制信号，使得激光光源模块提供给干涉测量模块两束固定频差的激光；控制处理模块控制干涉测量模块进行干涉测量，测量时激光在干涉测量模块中的两个Fabry-Perot腔内分别进行干涉并分别被两个光电探测器探测形成主副测量干涉信号；光学游标解调模块对干涉测量模块得到的主副测量干涉信号进行解调，解调结果通过控制处理模块计算得到被测位移。
作为优选，所述干涉测量模块，包括：第一光电探测器、第二光电探测器、第一精密位移台、第一谐振平面镜、第二谐振平面镜、第一角锥反射镜、第二精密位移台；其中，激光光源模块发出主激光束与副激光束；主激光束射进由固定于第一精密位移台上的第一谐振平面镜与固定于第二精密位移台上的第一角锥反射镜构成的第一Fabry-Perot腔内进行干涉形成主测量干涉光束，主测量干涉光束被第一光电探测器接收形成主测量干涉信号；副激光束射进由第二谐振平面镜与第一角锥反射镜构成的第二Fabry-Perot腔内进行干涉形成副测量干涉光束，副测量干涉光束被第二光电探测器接收形成副测量干涉信号。
作为优选，包括：第一光电探测器、第二光电探测器、第一精密位移台、第二谐振平面镜、第一角锥反射镜、第二精密位移台、第二角锥反射镜、第三谐振平面镜、反射镜、分光板、第三光电探测器、分光镜；其中，激光光源模块发出两束固定频差的主激光束与副激光束；主激光束被分光板分成第一子主激光束与第二子主激光束；第一子主激光束被反射进由固定于第一精密位移台上的第三谐振平面镜 与固定于第二精密位移台上的第一角锥反射镜构成的第一Fabry-Perot腔内进行干涉形成第一子主测量干涉光束，第一子主测量干涉光束经过分光镜透射后被第一光电探测器接收形成第一子主测量干涉信号；第二子主激光束被反射进由第三谐振平面镜与第二角锥反射镜构成的第二Fabry-Perot腔内进行干涉形成第二子主测量干涉光束，第二子主测量干涉光束经过分光镜反射后被第三光电探测器接收形成第二子主测量干涉信号；第一子主测量干涉信号和第二子主测量干涉信号构成主测量干涉信号；副激光束被反射镜反射进由第二谐振平面镜与第一角锥反射镜构成的第三Fabry-Perot腔内进行干涉形成副测量干涉光束，副测量干涉光束被第二光电探测器接收形成副测量干涉信号。
作为优选，所述的第一谐振平面镜为两端具有第一反射率的平面镜，所述第一反射率为2.5％～97.6％；所述的第二谐振平面镜为中间全透射且两端具有第二反射率的平面镜，所述第二反射率为2.5％～97.6％。
作为优选，所述的第二谐振平面镜为中间全透射且两端具有第二反射率的平面镜，所述第二反射率为2.5％～97.6％；所述的第三谐振平面镜为中间具有第三反射率且两端具有第四反射率的平面镜，所述第三反射率为90％～97.6％，所述第四反射率为2.5％～97.6％。
本发明还提供一种激光位移测量方法，包括以下步骤：
步骤1、信号调制模块对激光光源模块进行调制，使其发出两束波长分别为λ、λ
0的激光射进干涉测量模块进行干涉测量；
步骤2、控制处理模块控制干涉测量模块进行干涉测量；波长为λ、λ
0的激光分别射向由第一精密位移台、第一谐振平面镜、第一角锥反射镜和第二精密位移台构成的主Fabry-Perot干涉仪和由第二谐振平面镜、第一角锥反射镜和第二精密位移台构成的副Fabry-Perot干涉仪内进行干涉形成主测量干涉光束和副测量干涉光束，然后分别由第一、二光电探测器接收；
步骤3、控制处理模块控制第二精密位移台移动，使得第一角锥反射镜来回扫描；
步骤4、第一谐振平面镜移动位移ΔL时，由第一光电探测器探测主测量干涉光束，得到主测量干涉信号；由第二光电探测器探测副测量干涉光束，得到副测量干涉信号；光学游标解调模块通过光学游标原理对主测量干涉信号与副测量干涉信号进行解调，解调出位移小数个数M，由控制处理模块计算得到位移小数l：
步骤5、当第二谐振平面镜移动位移超过一个Fabry-Perot干涉峰时，即移动超过一个位移大数，光学游标解调模块解调出位移大数个数N，由控制处理模块计算得到位移大数L：
步骤6、控制处理模块通过计算位移大数、位移小数，再根据以下公式计算得到被测位移ΔL，
ΔL＝L+l
至此求出第一谐振平面镜的运动位移。
作为优选，所述的第一谐振平面镜为两端具有第一反射率的平面镜，所述第一反射率为2.5％～97.6％；所述的第二谐振平面镜为中间全透射且两端具有第二反射率的平面镜，所述第二反射率为2.5％～97.6％。
本发明还提供一种激光位移测量方法，包括以下步骤：
步骤1、信号调制模块对激光光源模块进行调制，使其发出两束波长分别为λ、λ
0的激光射进干涉测量模块进行干涉测量；
步骤2、控制处理模块控制干涉测量模块进行干涉测量；波长为λ的激光被分光板分成第一子主激光束与第二子主激光束，第一子主激光束、第一子主激光束与波长λ
0的激光分别射向由第一精密位移台、第三谐振平面镜、第一角锥反射镜、第二精密位移台构成的第一主Fabry-Perot干涉仪，由第一精密位移台、第三谐振平面镜、第二角锥反射镜构成的第二主Fabry-Perot干涉仪和由第二谐振平面镜、第一角锥反射镜、第二精密位移台构成的副Fabry-Perot干涉仪内进行干涉形成第一子主测量干涉光束、第二子主测量干涉光束与副测量干涉光束，然后分别被第一、二、三光电探测器接收；
步骤3、控制处理模块控制第二精密位移台移动，使得第一角锥反射镜来回扫描；
步骤4、第三谐振平面镜移动位移ΔL时，由第一光电探测器探测第一子主测量干涉光束，得到第一子主测量干涉信号；由第二光电探测器探测副测量干涉光束，得到副测量干涉信号；由第三光电探测器探测第二子主测量干涉光束，得到第二子主测量干涉信号；
步骤5、光学游标解调模块通过光学游标原理对第一子主测量干涉信号与副测量干涉信号进行解调，解调出位移小数个数M，由控制处理模块计算得到位移小数l：
步骤6、光学游标解调模块对第二子主测量干涉信号进行解调得到位移大数个数，由控制处理模块计算得到位移大数L：
步骤7、控制处理模块通过计算位移大数、位移小数，再根据以下公式计算得到被测位移ΔL，
ΔL＝L+l+l
0
至此求出第三谐振平面镜的运动位移，其中，l
0为机械置零时第一子主测量干涉信号与第二子主测量干涉信号之间的光强峰位移差值。
作为优选，所述的第二谐振平面镜为中间全透射且两端具有第二反射率的平面镜，所述第二反射率为2.5％～97.6％；所述的第三谐振平面镜为中间具有第三反射率且两端具有第四反射率的平面镜，所述第三反射率为90％～97.6％，所述第四反射率为2.5％～97.6％。
本发明具有的有益效果是：
(1)本发明通过主副测量激光束之间存在一定波长差，采用光学游标原理进行位移解析，能实现亚皮米级分辨力的位移测量。
(2)本发明采用的Fabry-Perot干涉仪实现位移大小数结合测量位移，能够克服Fabry-Perot腔无法满足长距离干涉测量等问题。
(3)本发明，采用的双频双Fabry-Perot腔结构，抗干扰能力强，能够实现长距离高精度的测量。
为了更清楚地说明本发明实施例或现有技术中的技术方案，下面将对实施例中所需要使用的附图作简单地介绍，显而易见地，下面描述中的附图仅仅是本发明的一些实施例，对于本领域普通技术人员来讲，在不付出创造性劳动性的前提下，还可以根据这些附图获得其他的附图。
图1是本发明激光位移测量装置的工作原理图；
图2是本发明干涉测量模块的光学原理示意图；
图3是本发明干涉测量模块另一种结构的光学原理示意图；
图4是不同波长进行Fabry-Perot干涉形成的干涉峰信号图；
图中：1、干涉测量模块，2、激光光源模块，3、信号调制模块，4、控制处理模块，5、光学游标解调模块，6、第一光电探测器，7、第二光电探测器，8、第一精密位移台，9、第一谐振平面镜，10、第二谐振平面镜，11、第一角锥反射镜，12、第二精密位移台，13、第二角锥反射镜，14、第三谐振平面镜，15、反射镜，16、分光板，17、第三光电探测器，18、分光镜。
下面将结合本发明实施例中的附图，对本发明实施例中的技术方案进行清楚、完整地描述，显然，所描述的实施例仅仅是本发明一部分实施例，而不是全部的实施例。基于本发明中的实施例，本领域普 通技术人员在没有做出创造性劳动前提下所获得的所有其他实施例，都属于本发明保护的范围。
为使本发明的上述目的、特征和优点能够更加明显易懂，下面结合附图和具体实施方式对本发明作进一步详细的说明。
实施例1
游标效应最初应用于提高长度测量的分辨率(如游标卡尺)，其工作原理在于巧妙利用主尺与游标的微小比例尺差异来进行长度测量。光学游标原理就是游标效应在光学干涉中的应用，当两个具有波长差的激光进行Fabry-Perot干涉时，会形成两个具有微小差异的干涉信号，与游标卡尺的主尺与游标具有异曲同工之妙。通过对这两个干涉信号进行解调，就能通到光学游标和光学主尺得到亚皮米级分辨力的位移读数。采用Fabry-Perot干涉技术的激光波长测量装置和方法
Fabry-Perot干涉为多光束干涉，根据多光束干涉的公式：
其中，I为透射光光强，a为入射光光振幅，R为Fabry-Perot腔谐振镜的光强反射率，d为Fabry-Perot腔腔长，λ为入射光波长。折叠Fabry-Perot腔干涉峰的间隔Δd与干涉波长λ之间的关系可表示为：
如图4所示，根据干涉激光波长的不同，随着Fabry-Perot腔的变化会出现间距不同的干涉峰。如果两个Fabry-Perot腔的干涉波长非常接近，那么他们分别进行干涉后形成的干涉峰间隔也会非常接近。 比如波长为633nm与波长为632.996nm分别进行干涉形成的干涉峰间隔的差值就为1pm。利用这两个具有不同等间隔的干涉峰就能构建光学主尺与光学游标，根据不同的波长差值就能形成不同分辨率的光学游标尺。
如图1所示，本发明提供一种激光位移测量装置包括：干涉测量模块1，激光光源模块2，信号调制模块3，控制处理模块4，光学游标解调模块5组成；所述信号调制模块3对激光光源模块2的激光进行调制，使得激光光源模块2提供给干涉测量模块1两束固定频差的激光。控制处理模块4控制干涉测量模块1进行干涉测量。光学游标解调模块2对干涉测量模块1得到的干涉信号进行解调，解调结果通过控制处理模块4计算得到被测位移；
如图2所示，所述的干涉测量模块1包括第一光电探测器6、第二光电探测器7、第一精密位移台8、第一谐振平面镜9、第二谐振平面镜10、第一角锥反射镜11、第二精密位移台12；激光光源模块2发出两束激光，主激光束与副激光束；主激光束射进由固定于第一精密位移台8上的第一谐振平面镜9与固定于第二精密位移台12上的第一角锥反射镜11构成的第一Fabry-Perot腔内进行干涉形成主测量干涉光束，主测量干涉光束被第一光电探测器6接收形成主测量干涉信号。副激光束射进由第二谐振平面镜10与第一角锥反射镜11构成的第二Fabry-Perot腔内进行干涉形成副测量干涉光束。副测量干涉光束被第二光电探测器7接收形成副测量干涉信号。
记第一精密位移台8、第一谐振平面镜9、第一角锥反射镜11和第二精密位移台12组成的干涉仪为主Fabry-Perot干涉仪，第二谐振平面镜10、第一角锥反射镜11和第二精密位移台12组成的干涉仪为副Fabry-Perot干涉仪；由第二谐振平面镜10与第一角锥反射镜11构成的第二Fabry-Perot腔为主Fabry-Perot干涉仪与副Fabry-Perot干涉仪公共腔体。
由此构成两套干涉仪，通过使主副测量激光束之间存在一定波长差，第一角锥反射镜11来回扫描，构成光学游标，采用大小数结合可准确计算第一谐振平面镜9的位移。
进一步，所述的第一谐振平面镜为两端具有第一反射率的平面镜，所述第一反射率为2.5％～97.6％；所述的第二谐振平面镜为中间全透射且两端具有第二反射率的平面镜，所述第二反射率为2.5％～97.6％。
本发明还提供一种激光位移测量方法，实施过程如下：
测量开始时，由控制处理模块4控制的信号调制模块3给激光光源模块2施加光源调制信号，使激光光源模块2发出两束波长分别为λ
0、λ
1的激光射进干涉测量模块1进行干涉得到主测量干涉信号、副测量干涉信号，此时的光学游标长度即光学主尺与光学副尺两次对准位置之间的长度，为：
主副测量干涉信号同时送入到光学游标解调模块5中，光学游标解调模块5对主副测量干涉信号进行解调判断，判断主副测量干涉信号是否同时到达干涉峰值。
若主副测量干涉信号没有同时到达干涉峰值，则光学游标解调模块5给控制处理模块4发送未检测到零点的信号，控制处理模块4接收到未检测到零点信号后，控制干涉测量模块1中的第二精密位移台12移动，固定其上的第一角锥反射镜11移动，移动的同时，光学游标解调模块5对主副测量干涉信号进行解调判断，判断其是否同时到达干涉峰值点，判断后将判断结果发送给控制处理模块4。直到判断结果为主副测量干涉信号同时到达干涉峰值点，控制处理模块4控制第二精密位移台12停止移动，并记下第二精密位移台12此时的位置L
0。
此时干涉测量模块1形成的主副测量干涉信号都达到干涉峰值点，从而实现对本发明装置的机械置零。
测量时，控制处理模块4控制第一精密位移台8移动，使得固定其上的第一谐振平面镜9以小于一个主测量干涉信号峰值间隔的步进值移动，每步进一次停止后，控制处理模块4控制第二精密位移台12从位置L
0开始向第一谐振平面镜9移动方向扫描一个光学游标长度l
y，使得第一角锥反射镜11扫描一个光学游标长度l
y。
扫描过程中主副测量干涉信号同时送入到光学游标解调模块5中进行解调判断，判断主副测量干涉信号是否同时到达干涉峰值。判断过程中，同时对副测量干涉信号经过的干涉峰值个数进行计数，即对位移小数计数。当主副测量干涉信号同时到达干涉峰值时，光学游标解调模块5将主副测量干涉信号同时到达干涉峰值点的信号与副测量干涉信号经过的干涉峰值个数M的信号发送到控制处理模块4， 控制处理模块4控制第一角锥反射镜11停止扫描，并回到L
0位置处。同时按照公式(4)进行计算得到位移小数l：
当主副测量干涉信号同时到达干涉峰值点时副测量干涉信号经过的干涉峰值个数比上一次解调出来的位移小数个数小，此时代表第一谐振平面镜9移动了一个位移大数，控制处理模块4经此类推得出位移大数个数N，通过公式(5)进行计算得到位移大数：
最后控制处理模块4根据公式(6)计算得到被测位移ΔL，然后进行下一次位移测量。
ΔL＝L+l (6)
实施例2
本实施例中，干涉测量模块采用原理图3的装置。如图3所示，所述干涉测量模块1在图2中干涉测量装置基础上增加了一路由第一精密位移台、第三谐振平面镜、第二角锥反射镜构成的Fabry-Perot干涉仪，且采用第二谐振平面镜10替换第一谐振平面镜9。具体包括第一光电探测器6、第二光电探测器7、第一精密位移台8、第二谐振平面镜10、第一角锥反射镜11、第二精密位移台12、第二角锥反射镜13、第三谐振平面镜14、反射镜15、分光板16、第三光电探测器17、分光镜18；激光光源模块2发出两束固定频差的激光，主激光束与副激光束；主激光束被分光板15分成两束激光，即第一子主激光束与第一子主激光束。第一子主激光束被反射进由固定于第一 精密位移台8上的第三谐振平面镜14与固定于第二精密位移台12上的第一角锥反射镜11构成的第一Fabry-Perot腔内进行干涉形成第一子主测量干涉光束，第一子主测量干涉光束经过分光镜17透射后被第一光电探测器6接收形成第一子主测量干涉信号。第二子主激光束被反射进由第三谐振平面镜14与第二角锥反射镜13构成的第二Fabry-Perot腔内进行干涉形成第二子主测量干涉光束，第二子主测量干涉光束经过分光镜18反射后被第三光电探测器17接收形成第二子主测量干涉信号。第一子主测量干涉信号、第二子主测量干涉信号构成主测量干涉信号。副激光束被反射镜15反射进由第二谐振平面镜10与第一角锥反射镜11构成的第三Fabry-Perot腔内进行干涉形成副测量干涉光束，副测量干涉光束被第二光电探测器7接收形成副测量干涉信号。
进一步，所述的第二谐振平面镜为中间全透射且两端具有第二反射率的平面镜，所述第二反射率为2.5％～97.6％；所述的第三谐振平面镜为中间具有第三反射率且两端具有第四反射率的平面镜，所述第三反射率为90％～97.6％，所述第四反射率为2.5％～97.6％。
本发明还提供一种激光位移测量方法，实施过程如下：
测量开始时，由控制处理模块4控制的信号调制模块3给激光光源模块2施加光源调制信号，使激光光源模块2发出两束波长分别为λ
0、λ
1的激光射进干涉测量模块1进行干涉得到第一子主测量干涉信号I
0、第二子主测量干涉信号I
1、副测量干涉信号I
2，此时的光学游 标长度为
即光学主尺与光学副尺两次对准位置之间的长度。
测量干涉信号I
0、I
1、I
2同时送入到光学游标解调模块5中，光学游标解调模块5对测量干涉信号I
0、I
1、I
2进行解调判断，判断测量干涉信号I
0、I
2是否同时到达干涉峰值点。
若测量干涉信号I
0、I
2没有同时到达干涉峰值点，则光学游标解调模块5给控制处理模块4发送未检测到零点的信号，控制处理模块4接收到未检测到零点信号后，控制干涉测量模块1中的第二精密位移台12移动，固定其上的第一角锥反射镜11移动，移动的同时，光学游标解调模块5对测量干涉信号I
0、I
2进行解调判断，判断其是否同时到达干涉峰值点，判断后将判断结果发送给控制处理模块4。直到判断结果为测量干涉信号I
0、I
2同时到达干涉峰值点，控制处理模块4控制第二精密位移台12停止移动，并记下第二精密位移台12此时的位置L
0。
控制处理模块4控制第一精密位移台8移动，使得固定其上的第三谐振平面镜14移动，在这过程中，光学游标解调模块5对第二子主测量干涉信号进行解调判断，当第二子主测量干涉信号到达第一个干涉峰时，控制处理模块4控制第一精密位移台8停止移动。
控制处理模块4控制第二精密位移台12从位置L
0开始向第三谐振平面镜14移动方向扫描一个光学游标长度l
y，使得第一角锥反射镜11扫描一个光学游标长度l
y。
扫描过程中光学游标解调模块5对测量干涉信号I
0、I
2进行解调判断，判断测量干涉信号I
0、I
2是否同时到达干涉峰值点。判断过程中，同时对副测量干涉信号I
2经过的干涉峰值个数进行计数，即对位移小数计数，当测量干涉信号I
0、I
2同时到达干涉峰值点时，光学游标解调模块5将测量干涉信号I
0、I
2同时到达干涉峰值点的信号与副测量干涉信号I
2经过的干涉峰值个数M的信号发送到控制处理模块4，控制处理模块4通过公式(4)计算得到位移小数，并记住此时解调出来的位移小数l
0。控制处理模块4控制第二精密位移台12回到位置L
0处。
此时干涉测量模块1形成的测量干涉信号I
0、I
2都达到干涉峰值点，从而实现对本发明装置的机械置零。
测量时，控制处理模块4控制第一精密位移台8移动，使得固定其上的第三谐振平面镜14移动，在这过程中，光学游标解调模块5对第二子主测量干涉信号I
1经过的干涉峰值个数N进行计数，即对位移大数计数。
第一精密位移台8停止移动后，控制处理模块4控制第二精密位移台12从位置L
0开始向第三谐振平面镜14移动方向重复扫描一个光学游标长度l
y，使得第一角锥反射镜11扫描一个光学游标长度l
y。
扫描过程中光学游标解调模块5对测量干涉信号I
0、I
2进行解调判断，判断测量干涉信号I
0、I
2是否同时到达干涉峰值点。判断过程中，同时对副测量干涉信号I
2经过的干涉峰值个数进行计数，即对位移小数计数，当测量干涉信号I
0、I
2同时到达干涉峰值点时，光学游 标解调模块5将测量干涉信号I
0、I
2同时到达干涉峰值点的信号与副测量干涉信号I
2经过的干涉峰值个数M的信号以及第二子主测量干涉信号I
1经过的干涉峰值个数N信号发送到控制处理模块4，控制处理模块4通过公式(4)计算得到位移小数，通过公式(5)计算得到位移大数。
最终的被测位移按照下面的规则给出：
一、当第二子主测量干涉信号没有到达第一个干涉峰时，最终的被测位移为位移小数：
ΔL＝l (7)
二、当第二子主测量干涉信号经过第一个干涉峰后：
1、l
0不为零，代表第一角锥反射镜11扫描起点处，第二子主测量干涉信号不在干涉峰的位置，此时：
a、位移小数l大于l
0时：
b、位移小数l小于l
0时：
ΔL＝L+l (9)
2、l
0为零，代表第一角锥反射镜11扫描起点处，第二子主测量干涉信号在干涉峰的位置，此时：
ΔL＝L+l (10)
最终计算得到被测位移ΔL，然后进行下一次测量。
在本发明的描述中，需要理解的是，术语“纵向”、“横向”、“上”、“下”、“前”、“后”、“左”、“右”、“竖直”、“水平”、“顶”、“底”、“内”、 “外”等指示的方位或位置关系为基于附图所示的方位或位置关系，仅是为了便于描述本发明，而不是指示或暗示所指的装置或元件必须具有特定的方位、以特定的方位构造和操作，因此不能理解为对本发明的限制。
以上所述的实施例仅是对本发明的优选方式进行描述，并非对本发明的范围进行限定，在不脱离本发明设计精神的前提下，本领域普通技术人员对本发明的技术方案做出的各种变形和改进，均应落入本发明权利要求书确定的保护范围内。
Claims (9)
- 一种激光位移测量装置，其特征在于，包括：干涉测量模块、激光光源模块、信号调制模块、控制处理模块、光学游标解调模块；其中，控制处理模块控制信号调制模块给激光光源模块施加光源调制信号，使得激光光源模块提供给干涉测量模块两束固定频差的激光；控制处理模块控制干涉测量模块进行干涉测量，测量时激光在干涉测量模块中的两个Fabry-Perot腔内分别进行干涉并分别被两个光电探测器探测形成主副测量干涉信号；光学游标解调模块对干涉测量模块得到的主副测量干涉信号进行解调，解调结果通过控制处理模块计算得到被测位移。
- 如权利要求1所述的激光位移测量装置，其特征在于，所述干涉测量模块，包括：第一光电探测器、第二光电探测器、第一精密位移台、第一谐振平面镜、第二谐振平面镜、第一角锥反射镜、第二精密位移台；其中，激光光源模块发出主激光束与副激光束；主激光束射进由固定于第一精密位移台上的第一谐振平面镜与固定于第二精密位移台上的第一角锥反射镜构成的第一Fabry-Perot腔内进行干涉形成主测量干涉光束，主测量干涉光束被第一光电探测器接收形成主测量干涉信号；副激光束射进由第二谐振平面镜与第一角锥反射镜构成的第二Fabry-Perot腔内进行干涉形成副测量干涉光束，副测量干涉光束被第二光电探测器接收形成副测量干涉信号。
- 如权利要求1所述的激光位移测量装置，其特征在于，所述干涉测量模块包括：第一光电探测器、第二光电探测器、第一精密位移台、第二谐振平面镜、第一角锥反射镜、第二精密位移台、第二角锥 反射镜、第三谐振平面镜、反射镜、分光板、第三光电探测器、分光镜；其中，激光光源模块发出两束固定频差的主激光束与副激光束；主激光束被分光板分成第一子主激光束与第二子主激光束；第一子主激光束被反射进由固定于第一精密位移台上的第三谐振平面镜与固定于第二精密位移台上的第一角锥反射镜构成的第一Fabry-Perot腔内进行干涉形成第一子主测量干涉光束，第一子主测量干涉光束经过分光镜透射后被第一光电探测器接收形成第一子主测量干涉信号；第二子主激光束被反射进由第三谐振平面镜与第二角锥反射镜构成的第二Fabry-Perot腔内进行干涉形成第二子主测量干涉光束，第二子主测量干涉光束经过分光镜反射后被第三光电探测器接收形成第二子主测量干涉信号；第一子主测量干涉信号和第二子主测量干涉信号构成主测量干涉信号；副激光束被反射镜反射进由第二谐振平面镜与第一角锥反射镜构成的第三Fabry-Perot腔内进行干涉形成副测量干涉光束，副测量干涉光束被第二光电探测器接收形成副测量干涉信号。
- 权利要求2所述的激光位移测量装置，其特征在于，所述的第一谐振平面镜为两端具有第一反射率的平面镜，所述第一反射率为2.5％～97.6％；所述的第二谐振平面镜为中间全透射且两端具有第二反射率的平面镜，所述第二反射率为2.5％～97.6％。
- 权利要求3所述的激光位移测量装置，其特征在于，所述的第二谐振平面镜为中间全透射且两端具有第二反射率的平面镜，所述第二反射率为2.5％～97.6％；所述的第三谐振平面镜为中间具有第三反射率且两端具有第四反射率的平面镜，所述第三反射率为90％～97.6％， 所述第四反射率为2.5％～97.6％。
- 一种激光位移测量方法，其特征在于，包括以下步骤：步骤1、信号调制模块对激光光源模块进行调制，使其发出两束波长分别为λ、λ 0的激光射进干涉测量模块进行干涉测量；步骤2、控制处理模块控制干涉测量模块进行干涉测量；波长为λ、λ 0的激光分别射向由第一精密位移台、第一谐振平面镜、第一角锥反射镜和第二精密位移台构成的主Fabry-Perot干涉仪和由第二谐振平面镜、第一角锥反射镜和第二精密位移台构成的副Fabry-Perot干涉仪内进行干涉形成主测量干涉光束和副测量干涉光束，然后分别由第一、二光电探测器接收；步骤3、控制处理模块控制第二精密位移台移动，使得第一角锥反射镜来回扫描；步骤4、第一谐振平面镜移动位移ΔL时，由第一光电探测器探测主测量干涉光束，得到主测量干涉信号；由第二光电探测器探测副测量干涉光束，得到副测量干涉信号；光学游标解调模块通过光学游标原理对主测量干涉信号与副测量干涉信号进行解调，解调出位移小数个数M，由控制处理模块计算得到位移小数l：
步骤5、当第二谐振平面镜移动位移超过一个Fabry-Perot干涉峰时，即移动超过一个位移大数，光学游标解调模块解调出位移大数个数N，由控制处理模块计算得到位移大数L：
步骤6、控制处理模块通过计算位移大数、位移小数，再根据以下公式计算得到被测位移ΔL，ΔL＝L+l至此求出第一谐振平面镜的运动位移。 - 权利要求6所述的激光位移测量方法，其特征在于，所述的第一谐振平面镜为两端具有第一反射率的平面镜，所述第一反射率为2.5％～97.6％；所述的第二谐振平面镜为中间全透射且两端具有第二反射率的平面镜，所述第二反射率为2.5％～97.6％。
- 一种激光位移测量方法，其特征在于，包括以下步骤：步骤1、信号调制模块对激光光源模块进行调制，使其发出两束波长分别为λ、λ 0的激光射进干涉测量模块进行干涉测量；步骤2、控制处理模块控制干涉测量模块进行干涉测量；波长为λ的激光被分光板分成第一子主激光束与第二子主激光束，第一子主激光束、第一子主激光束与波长λ 0的激光分别射向由第一精密位移台、第三谐振平面镜、第一角锥反射镜、第二精密位移台构成的第一主Fabry-Perot干涉仪，由第一精密位移台、第三谐振平面镜、第二角锥反射镜构成的第二主Fabry-Perot干涉仪和由第二谐振平面镜、第一角锥反射镜、第二精密位移台构成的副Fabry-Perot干涉仪内进行干涉形成第一子主测量干涉光束、第二子主测量干涉光束与副测量干涉光束，然后分别被第一、二、三光电探测器接收；步骤3、控制处理模块控制第二精密位移台移动，使得第一角锥反射镜来回扫描；步骤4、第三谐振平面镜移动位移ΔL时，由第一光电探测器探测第一子主测量干涉光束，得到第一子主测量干涉信号；由第二光电探测器探测副测量干涉光束，得到副测量干涉信号；由第三光电探测器探测第二子主测量干涉光束，得到第二子主测量干涉信号；步骤5、光学游标解调模块通过光学游标原理对第一子主测量干涉信号与副测量干涉信号进行解调，解调出位移小数个数M，由控制处理模块计算得到位移小数l：
步骤6、光学游标解调模块对第二子主测量干涉信号进行解调得到位移大数个数，由控制处理模块计算得到位移大数L：
步骤7、控制处理模块通过计算位移大数、位移小数，再根据以下公式计算得到被测位移ΔL，ΔL＝L+l+l 0至此求出第三谐振平面镜的运动位移，其中，l 0为机械置零时第一子主测量干涉信号与第二子主测量干涉信号之间的光强峰位移差值。 - 权利要求8所述的激光位移测量方法，其特征在于，所述的第二谐振平面镜为中间全透射且两端具有第二反射率的平面镜，所述第二反射率为2.5％～97.6％；所述的第三谐振平面镜为中间具有第三反射率且两端具有第四反射率的平面镜，所述第三反射率为90％～97.6％，所述第四反射率为2.5％～97.6％。
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