Phase modulation grating sensor and method for realizing measurement

Abstract

The invention discloses a phase modulation grating sensor and a method for realizing measurement. Phase modulation based on PZT is performed to grating measurement signals so as to prevent direct current shift and amplitude value fluctuation from influencing nanometer measurement signals; an error detection module is embedded to real-timely compensate the alignment error of the grating sensor so as to realize displacement and length measurement in nanometer accuracy; and the phase modulation grating sensor comprises an optical path part and a signal processing part. The phase modulation grating sensor and the method have the advantages as follows: installation and adjustment are simplified; redundant reflection beams are reduced; signal quality is improved; interference of the environment to the system is reduced; based on the FPGA signal processing part, the signal processing speed of the system is increased; and by phase modulation, direct current shift and amplitude value fluctuation can be prevented from influencing the measuring signals effectively, so that measurement in nanometer accuracy is realized.

Description

technical field [0001] The invention relates to a phase modulation grating sensor used for nanometer precision measurement of displacement and length and a method for realizing the measurement. Background technique [0002] The industry based on nanotechnology and the semiconductor equipment industry require highly reliable instruments with fast and stable positioning capabilities and sub-nanometer precision. Now, laser interferometers, capacitance measuring instruments and grating sensors can achieve sub-nanometer resolution, but they all have their own problems, such as laser interferometers are sensitive to changes in air temperature, humidity and atmospheric pressure, which affects the repeatability of measurements sex. The measuring range of the capacitance measuring instrument is small, and the adjustment process is difficult during installation. The structure of the grating sensor is compact, and the error averaging effect of the grating measurement, the signal stab...

AI Technical Summary

Problems solved by technology

When the measurement signal is read, due to low-pass filter noise reduction and the inherent characteristics of photoelectric conversion devices, the amplitude of the measurement signal decreases when the measurement speed is high. In the application process, although digital signal processing can be used to achieve good amplitude stabilization , but these methods are to predict the signal amplitude correction method at the next time point from the change law of the amplitude, and the real-time performance is poor, which limits the measurement speed in practical applications

[0013] (2) The measurement system lacks real-time error compensation and calibration correction technology in laser grating nanosensors

However, the current literature report system does not have a real-time error measurement compensation module

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