US 11,885,879 B2Granted

Measurement apparatus and measurement method

AssigneeMitutoyo Corporation

InventorsYoshimasa Suzuki, Shinichi Hara, Hiroki Ujihara

Life of this patent

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Abstract

A measurement apparatus includes a laser apparatus, a branch that branches a frequency-modulated laser beam into a reference light and a measurement light, a beat signal generator that generates a beat signal by mixing the reference light and a reflected light that is the measurement light radiated onto an object to be measured, a first analyzer that analyses a first signal component corresponding to a difference in a propagation distance between the reference light and the measurement light on the basis of the beat signal, a second analyzer that analyses a second signal component corresponding to a cavity frequency of an optical cavity on the basis of the beat signal, and calculation circuitry that calculates the difference in the propagation distance between the reference light and the measurement light.

Claims16

Dependent claims

A measurement apparatus comprising:

a laser apparatus that has an optical cavity and outputs a frequency-modulated laser beam with a plurality of modes;
a branch that branches a first portion of the frequency-modulated laser beam output by the laser apparatus as a reference light and at least some of a remaining second portion of the frequency-modulated laser beam as a measurement light;
a beat signal generator that generates a beat signal by mixing the reference light and a reflected light that is reflected by radiating the measurement light onto an object;
first analyzer circuitry configured to analyze a first signal component corresponding to a difference in a propagation distance between the reference light and the measurement light on the basis of the beat signal;
second analyzer circuitry configured to analyze a second signal component corresponding to a cavity frequency of the optical cavity on the basis of the beat signal;
and
calculation circuitry configured to calculate the difference in the propagation distance between the reference light and the measurement light based on analysis results of the first signal component and the second signal component.

4 more elements

A measurement method comprising:

outputting a frequency-modulated laser beam with a plurality of modes from a laser apparatus having an optical cavity;
branching a first portion of the frequency-modulated laser beam as a reference light and at least some of a remaining second portion as a measurement light;
generating a beat signal by mixing the reference light and a reflected light that is reflected by radiating the measurement light onto an object to be measured;
analyzing a first signal component corresponding to a difference in a propagation distance between the reference light and the measurement light on the basis of the beat signal;
analyzing a second signal component corresponding to a cavity frequency of the optical cavity on the basis of the beat signal;
and
calculating the difference in the propagation distance between the reference light and the measurement light based on analysis results of the first signal component and the second signal component.

4 more elements

Dependencies are inferred from the claim text.

Facts

Application: 16/997,823Filed 19 Aug 2020
Priority: JP 2019-15378026 Aug 2019
Published: US 2021/0063573 A14 Mar 2021
Granted: 30 Jan 2024
Term ends: Not estimatedThe source records don’t support an estimate.

Classification4 codes

G01S 17/34
Using transmission of continuous waves, whether amplitude-, frequency-, or phase-modulated, or unmodulated: using transmission of continuous,…
G01S 7/4913
Receivers: circuits for detection, sampling, integration or read-out
G01S 7/4917
Receivers: superposing optical signals in a photodetector, e.g. optical heterodyne detection
G01S
Radio direction-finding