Title:
REAL-TIME NORMALIZATION MODIFICATION APPARATUS AND METHOD FOR PGC DEMODULATION IN SINE PHASE MODULATION INTERFEROMETER
Document Type and Number:
WIPO Patent Application WO/2019/062466
Kind Code:
A1
Abstract:
A real-time normalization modification apparatus for PGC demodulation in a sine phase modulation interferometer, containing an optical path structure for measuring an interferometer and monitoring the interferometer; an electro-optic phase modulator is placed in a common reference arm of the two interferometers, and high-frequency sinusoidal wave modulation and low-frequency triangular wave modulation are applied at the same time; the sinusoidal wave modulation is used for generating a phase carrier, and PGC demodulation is performed to obtain an orthogonal signal containing information about a phase to be measured; the triangular wave modulation enables the orthogonal signal to periodically change, and ellipse fitting is performed on a Lissajous figure corresponding to the orthogonal signal, so as to realize the real-time normalized modification of the PGC demodulated orthogonal signal; and a measured displacement is obtained by calculating a phase difference variation of two interference signals, realizing nanoscale displacement measurement. Also provided is displacement detection method based on real-time normalization processing of PGC demodulation in a sine phase modulation interferometer. Non-linear errors caused by changes in a phase modulation depth, a phase delay, a multiplier, a filter gain, etc. in PGC demodulation are eliminated, and there is a sub-nanoscale measurement precision, which is applicable for precise displacement measurement in the field of high-end equipment manufacturing and machining.
Inventors:
YAN LIPING (CN)
ZHANG SHIHUA (CN)
CHEN BENYONG (CN)
ZHANG SHIHUA (CN)
CHEN BENYONG (CN)
Application Number:
PCT/CN2018/103381
Publication Date:
April 04, 2019
Filing Date:
August 31, 2018
Export Citation:
Assignee:
UNIV ZHEJIANG SCIENCE & TECH (CN)
International Classes:
G01B9/02
Foreign References:
| CN107843189A | 2018-03-27 | |||
| CN105043243A | 2015-11-11 | |||
| CN103487133A | 2014-01-01 | |||
| CN101231367A | 2008-07-30 | |||
| CN105486225A | 2016-04-13 | |||
| CN102624456A | 2012-08-01 | |||
| EP1985967A1 | 2008-10-29 |
Attorney, Agent or Firm:
HANGZHOU QIUSHI PATENT OFFICE CO., LTD. (CN)
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