US 11,408,722 B2Granted

OCT measuring device and oct measuring method

AssigneePanasonic Intellectual Property Management Co., Ltd.

InventorsYohei Takechi, Jun Yokoyama

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Abstract

OCT measuring device in the present exemplary embodiment includes: wavelength sweep light source that emits light of which a wavelength is swept; optical interferometer that divides the light into measurement light and reference light, emits measurement light toward measurement surface of measuring target object, and generates an optical interference intensity signal indicating an intensity of interference between measurement light reflected from measurement surface and reference light; electro-optic element which is a phase modulator arranged in a light path of optical interferometer; measurement processor which is a signal generator that derives a position of measurement surface and generates a phase amount indicator signal that indicates a phase amount of phase modulator based on the optical interference intensity signal; and electro-optic element controller which is a phase amount controller that controls the phase amount given to the light that is transmitted through phase modulator.

Claims9

Dependent claims

An optical coherence tomography (OCT) measuring device comprising:

a wavelength sweep light source that emits light of which a wavelength is swept;
an optical interferometer that divides the light into measurement light and reference light, emits the measurement light toward a measurement surface of a measuring target object, and generates an optical interference intensity signal indicating an intensity of interference between the measurement light reflected from the measurement surface and the reference light;
a phase modulator arranged in a light path of the optical interferometer;
a signal generator that derives a position of the measurement surface and generates a phase amount indicator signal that indicates a phase amount of the phase modulator based on the optical interference intensity signal;
and
a phase amount controller that controls the phase amount given to the light that is transmitted through the phase modulator based on the phase amount indicator signal, wherein:
the signal generator calculates linear instantaneous phase change data that linearly changes from an instantaneous phase value of first data to an instantaneous phase value of last data in a section between a first wave number in the first data of the instantaneous phase change data and a last wave number in the last data of the instantaneous phase change data, calculates phase compensation data by taking a difference between the instantaneous phase change data and the linear instantaneous phase change data, and generates the phase compensation data as the phase amount indicator signal, and
the phase amount controller calculates a compensation voltage control signal based on the phase compensation data and a phase modulation control coefficient that controls a phase modulation amount, which is set in the phase modulator and a phase amount controller, and controls the phase amount by the compensation voltage control signal.

5 more elements

An optical coherence tomography (OCT) measuring method comprising:

detecting an optical interference intensity signal indicating an intensity of interference between measurement light emitted toward a measurement surface of a measuring target object and reflected from the measurement surface and reference light in a state in which a phase modulator arranged in a light path of an optical interferometer that generates the optical interference intensity signal indicating an intensity of interference with the reference light gives a phase to light transmitted through the light path based on a predetermined compensation voltage control signal, and calculating instantaneous phase change data indicating an instantaneous phase value at a wave number of the light emitted from a wavelength sweep light source that emits the light of which a wavelength is swept;
calculating linear instantaneous phase change data that linearly changes from an instantaneous phase value of first data to an instantaneous phase value of last data in a section between a first wave number in the first data of the instantaneous phase change data and a last wave number in the last data of the instantaneous phase change data;
calculating phase compensation data by taking a difference between the instantaneous phase change data and the linear instantaneous phase change data;
calculating a compensation voltage control signal based on the phase compensation data and a phase modulation control coefficient that controls a phase modulation amount, which is set in the phase modulator and a phase amount controller that controls the phase amount given to the light transmitted through the phase modulator;
storing the compensation voltage control signal in a controller;
giving a phase to the light transmitted through the light path using the compensation voltage control signal output from the controller based on the compensation voltage control signal in accordance with a wavelength sweep timing of the light emitted from the wavelength sweep light source by the phase modulator;
and
deriving a position of the measurement surface based on the optical interference intensity signal.

5 more elements

Dependencies are inferred from the claim text.

Facts

Application: 17/241,125Filed 27 Apr 2021
Priority: JP JP2020-0969693 Jun 2020
Published: US 2021/0381818 A19 Dec 2021
Granted: 9 Aug 2022
Term ends: Not estimatedThe source records don’t support an estimate.

Classification6 codes

G01B 9/0201
Characterised by controlling or generating intrinsic radiation properties: using temporal phase variation
G01B 9/02004
Using two or more frequencies: using frequency scans
G01B 9/02067
Active error reduction, i.e. varying with time: by electronic control systems, i.e. using feedback acting on optics or light
G01B 9/02091
Low-coherence interferometers: tomographic interferometers, e.g. based on optical coherence