Defect inspection device and defect inspection method

Patent metadata

Field	Value
Publication number	US-2023062821-A1
Application number	US-202017792405-A
Country	US
Kind code	A1
Filing date	Oct 12, 2020
Priority date	Jan 17, 2020
Publication date	Mar 2, 2023
Grant date	—

Abstract

A defect inspection device (100) includes an excitation unit that excites an elastic wave, an irradiation unit (2) that applies laser lights, a measurement unit (3) that measures the interfered laser lights, and a control unit that acquires vibration state information which is information about a state of the elastic wave excited in an inspection target (P) for a plurality of frequencies by changing a frequency of excitation vibration caused by the excitation unit in order to excite the elastic wave in the inspection target (P), and extracts recommended frequencies (F) recommended for inspecting a defect of the inspection target (P) from among the plurality of frequencies based on the acquired vibration state information for the plurality of frequencies.

First claim

1 . A defect inspection device comprising:
an excitation unit that excites an elastic wave in an inspection target; an irradiation unit that irradiates a measurement region of the inspection target with laser lights; a measurement unit that causes the laser lights reflected in the measurement region to interfere with each other by a laser interference method, and measures the interfered laser lights; and a control unit that acquires vibration state information which is information about a state of the elastic wave excited in the inspection target for a plurality of frequencies by changing a frequency of excitation vibration caused by the excitation unit in order to excite the elastic wave in the inspection target, and extracts recommended frequencies recommended for inspecting a defect of the inspection target from among the plurality of frequencies based on the acquired vibration state information for the plurality of frequencies.

2 . The defect inspection device according to claim 1 , wherein the control unit is configured to display the extracted recommended frequencies in an identifiable manner.

3 . The defect inspection device according to claim 2 , wherein the control unit is configured to display a measurement frequency to be used for measurement in a selectable manner from among the extracted recommended frequencies.

4 . The defect inspection device according to claim 1 , wherein the control unit is configured to acquire the vibration state information for the plurality of frequencies based on a phase difference between a voltage input to the excitation unit and a current input to the excitation unit.

5 . The defect inspection device according to claim 4 , wherein the control unit is configured to acquire the vibration state information based on a phase difference between a voltage pulse signal in which the voltage input to the excitation unit is converted into a pulse signal and a current pulse signal in which the current input to the excitation unit is converted into a pulse signal, and is configured to extract, as the recommended frequency, a frequency at which the phase difference between the voltage pulse signal and the current pulse signal becomes an extreme value from among the plurality of frequencies.

6 . The defect inspection device according to claim 1 , wherein the control unit is configured to acquire, as the vibration state information, an impedance of the excitation unit measured based on the voltage input to the excitation unit and the current input to the excitation unit for the plurality of frequencies.

7 . The defect inspection device according to claim 1 , wherein the control unit is configured to extract the recommended frequency by sequentially changing the frequency of the excitation vibration caused by the excitation unit in a predetermined band in order to excite the elastic wave in the inspection target, and is configured to change a band for changing a frequency of the elastic wave so as to correspond to a type of the defect of the inspection target.

8 . A defect inspection method comprising:
a step of exciting an elastic wave in an inspection target; a step of irradiating a measurement region of the inspection target with laser lights; a step of causing the laser lights reflected in the measurement region to interfere with each other by a laser interference method and measuring the interfered laser lights; and a step of acquiring vibration state information which is information about a state of the elastic wave excited in the inspection target for a plurality of frequencies by changing a frequency of excitation vibration caused in order to excite the elastic wave in the inspection target and extracting recommended frequencies recommended for inspecting a defect of the inspection target from among the plurality of frequencies based on the acquired vibration state information for the plurality of frequencies.

9 . The defect inspection method according to claim 8 , further comprising:
a step of displaying the extracted recommended frequencies in an identifiable manner.

10 . The defect inspection method according to claim 9 , further comprising:
a step of displaying the extracted recommended frequencies again in an identifiable manner after the step of measuring the interfered laser lights.

Assignees

• Shimadzu Corp

Inventors

• Yoshida Koki
• Takubo Kenji
• Hatahori Takahide

Classifications

• G01N29/12

  by measuring frequency or resonance of acoustic waves {(measuring frequency or resonant frequency of mechanical vibrations or acoustic waves in general G01H1/06, G01H3/04, G01H13/00; acoustic resonators G10K11/04; vibration or shock testing of structures G01M7/00)} · CPC title

• G01N29/2418 Primary

  using optoacoustic interaction with the material, e.g. laser radiation, photoacoustics (photoacoustic cells G01N21/1702; measuring characteristics of vibrations by using radiation-sensitive means G01H9/00; acousto-optical conversion techniques for short-range imaging G01S15/8965; sound-producing devices using laser bundle G10K15/046) · CPC title

• G01N29/348

  with frequency characteristics, e.g. single frequency signals, chirp signals (measuring frequency of mechanical vibrations or acoustic waves in general G01H1/06, G01H3/04; measuring frequency or analysing frequency spectra G01R23/00) · CPC title

• G01N21/88

  Investigating the presence of flaws or contamination · CPC title

• G01N2291/262

  Linear objects · CPC title