A laser displacement measuring device and method

A technology of laser displacement and measurement device, applied in the field of precision measurement, can solve problems such as the improvement of the accuracy of laser interferometer, resolution or limitation of measurement range, etc., to achieve the effect of strong anti-interference ability and long-distance high-precision measurement

Active Publication Date: 2021-11-09
NAT INST OF METROLOGY CHINA
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Problems solved by technology

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.
At the same time, the laser interference method is affected by the wavelength of the interference laser and the optical structure. When performing large-scale measurement, the resolution or measurement range of the interferometry will be limited to a certain extent, and both can not be taken into account.

Method used

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  • A laser displacement measuring device and method
  • A laser displacement measuring device and method
  • A laser displacement measuring device and method

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Embodiment 1

[0048] 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. When 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. . By demodulating these two interference signals, displacement readings with sub-picometer resolution can be obtained through the optical vernier and the optical main scale. Device and method for measuring laser wavelength using Fabry-Perot interferometry

[0049] Fabry-Perot interference is multi-beam interference, according to the formula of multi-beam interference:

[0050]

[0051] in, I is the transmitted light intensi...

Embodiment 2

[0073] In this embodiment, the interferometric module adopts the principle image 3 s installation. Such as image 3 As shown, the interferometric module 1 is in figure 2 On the basis of the interferometric measurement device, a Fabry-Perot interferometer consisting of the first precision translation stage, the third resonant plane mirror and the second corner mirror is added, and the first resonant plane mirror 9 is replaced by the second resonant plane mirror 10 . 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 third resonant plane mirror 14, reflector 15, beam splitter 16, third photodetector 17, beam splitter 18; the laser light source module 2 emits two laser beams with a fixed frequency difference, the main laser beam and the auxiliary laser beam; the ma...

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Abstract

The invention discloses a laser displacement measurement device and method, comprising: an interference measurement 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 the laser light source module The light source modulates the signal so that the laser light source module provides two laser beams with a fixed frequency difference to the interferometry module; the control processing module controls the interferometry module to perform interferometry, and the lasers are respectively carried out in two Fabry-Perot cavities in the interferometry module Interference is detected by two photodetectors respectively to form main and auxiliary measurement interference signals; the optical cursor demodulation module demodulates the main and auxiliary measurement interference signals obtained by the interferometric module, and the demodulation result is calculated by the control processing module to obtain the measured displacement. The invention has sub-picometer-level resolution and can be used for large-scale and high-precision measurement of displacement.

Description

technical field [0001] 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. Background technique [0002] 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 improveme...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01B11/02G01B9/02
CPCG01B11/02G01B9/02055
Inventor 崔建军张鹏陈恺
Owner NAT INST OF METROLOGY CHINA
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