Title:
LASER INTERFEROMETER
Document Type and Number:
Japanese Patent JP2023124106
Kind Code:
A
Abstract:
To provide a laser interferometer capable of suppressing a decrease in demodulation accuracy even when disturbance such as a temperature change is applied.SOLUTION: A laser interferometer comprises: a laser light source that emits laser light; an optical modulator that includes a vibration element driven by a driving signal and superimposes a modulation signal on the laser light; a photodetector that receives the laser light including a sample signal superimposed due to reflection by an object and the laser light including the modulation signal, and outputs a light receiving signal; a calculation section that performs a calculation on the light receiving signal on the basis of a reference signal; and a signal generation section that outputs the driving signal and the reference signal. The calculation section includes: a preprocessing section that outputs a preprocessing signal including a frequency modulation component on the basis of the reference signal; a demodulation processing section that demodulates the sample signal from the preprocessing signal on the basis of the reference signal; and a correction processing section that outputs a correction signal on the basis of an output signal output in response to driving of the vibration element. The signal generation section corrects the driving signal and the reference signal on the basis of the correction signal.SELECTED DRAWING: Figure 1
Inventors:
YAMADA KOHEI
SHIMIZU TAKESHI
SHIMIZU TAKESHI
Application Number:
JP2022027697A
Publication Date:
September 06, 2023
Filing Date:
February 25, 2022
Export Citation:
Assignee:
SEIKO EPSON CORP
International Classes:
G01H9/00
Attorney, Agent or Firm:
Satoshi Nakai
Hiroki Matsuoka
Masayuki Imamura
Hiroki Matsuoka
Masayuki Imamura
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