High precision prism displacement measuring device and method based on digital phase lock

Abstract

The invention relates to the high precision displacement measurement technical field, and more specifically relates to a high precision prism displacement measuring method based on a digital phase lock; the device does not need a wave-plate; a piezoelectric ceramics driver is added on a reference reflector so as to carry out sine modulation; the phase lock can amplify one time frequency and two time frequency signals, thus realizing high precision and high sensitivity measurement of displacement, and eliminating influences on measurements by background noises and laser intensity fluctuations;the method does not need to know a zero light path difference point and interpolation, only gathers PEM modulation interference signals for a time length (see description), and has nothing to do witha sampling start point and a finish point; the method uses the phase lock amplification technology to improve the displacement precision, can phase lock one time frequency signal and two time frequency signal amplitudes, and divides to eliminate the displacement measuring precision reduction problems caused by laser light intensity fluctuations; the displacement form is arc tangent, thus ensuringthe same linear sensitivity, and eliminating the low sensitivity problem of certain positions of a conventional sine and cosine.

Description

technical field [0001] The invention relates to the technical field of high-precision displacement measurement, and more particularly, to a high-precision prism displacement measurement method based on digital phase locking. Background technique [0002] With the rapid development of some cutting-edge technologies, in the fields of manufacturing, microelectronics, biology, and aerospace, there is an urgent need for displacement measurement systems that can achieve high precision and high sensitivity. Among them, the interferometry method is the most important method at this stage. The Michelson interferometric displacement sensor is the most classic optical interference displacement measurement method. The core component is the polarization beam splitter prism. Since the polarization directions of the two beams separated by the polarization beam splitter prism are orthogonal to each other, Therefore, it is necessary to add a wave plate, the structure is complex, and the util...

AI Technical Summary

Problems solved by technology

[0003] In order to overcome the deficiencies in the prior art, the present invention provides a high-precision prism displacement measurement device and method based on digital phase-locking, which solves the need to add wave plates, background noise and laser in the polarization beam splitter prism displacement measurement in the prior art. Intensity fluctuations lead to problems such as decreased measurement accuracy and sensitivity

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