Apparatus and method for measuring a defect of a sample

• US 6,450,035 B1
• Filed: 10/20/2000
• Issued: 09/17/2002
• Est. Priority Date: 02/25/2000
• Status: Expired due to Fees

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Nishizono, Shigeo
• Primary Examiner(s): Williams, Hezron
• Assistant Examiner(s): SAINT SURIN, JACQUES M
• Application Number:
  US09/692,201
• Time in Patent Office: 697 Days
• Field of Search: 735/79, 736/61, 735/99, 736/00, 736/02, 73/18.2, 735/98, 735/93, 735/91
• US Class Current: 73/579
• CPC Class Codes: G01N 2291/014 Resonance or resonant frequency
• CPC Class Codes: G01N 29/045 by imparting shocks to the workpiece and detecting the vibrations or the acoustic waves caused by the shocks measuring resonant frequency G01H13/00; measuring strength properties by application of mechanical stress G01N3/00

Abstract

An apparatus includes an inspection jig having a sample mounting fixture for mounting a sample, a vibrator for applying a vibration to the sample, and a sound collector for collecting vibration sound when the vibration is applied to the sample, and a sound detector for frequency analysis of the vibration sound collected by the sound collector. The sample is pinched and fixed by a contact surface of the sound collector and a fixing part with a contact area similar to the contact surface when the sample is mounted in the sample mounting fixture. The sample mounting fixture is mounted on a shaft of an inspection jig fixed in a bearing.

Claims

1. An apparatus for measuring defects of a sample, the apparatus comprising:

an inspection jig comprising;

an impact vibrator fort inducing vibrations in a sample;

a sample mounting fixture for mounting the sample; and

a sound collector mounted in the sample mounting fixture for collecting sound propagating in the sample and induced by impact of the impact vibrator, wherein the sample mounting fixture includes a movable jaw with a contact surface for resiliently clamping the sample between and in contact with the contact surface and the sound collector; and

a sound detector for frequency analysis of the sound collected by the sound collector.

2. The apparatus according to claim 1, wherein the sound collector has a first contact area contacting the sample, and the contact surface has a second contact area substantially the same as the first contact area.

3. The apparatus according to claim 2, wherein the contact surface of the sample mounting fixture includes a cushioning material and the jaw is movable in a direction opposite a direction in which the impact vibration is applied to the sample by the impact vibrator.

4. The apparatus according to claim 1, wherein an uneven surface of the sample is placed in contact with the sound collector in the sample mounting fixture.

5. The apparatus according to claim 1, wherein an application point of the impact vibrator is proximate a center of the sample.

6. The apparatus according to claim 1, further comprising a stop for maintaining impact force and a release point of the impact vibrator constant.

7. The apparatus according to claim 1, wherein the inspection jig includes a mount with a rotatable sleeve and the impact vibrator includes a mass suspended from the sleeve by a flexible line as a pendulum for inducing vibrations in the sample by impact of the mass against the sample.

8. The apparatus according to claim 1, wherein the sound detector comprises first and second low pass filters having different frequency ranges and connected in series, receiving and processing the sound collected by the sound collector to produce a first signal for frequency analysis, and a high pass filter receiving and processing the sound collected by the sound collector to produce a second signal for frequency analysis.

9. The apparatus according to claim 8, wherein, in the sound detector, an output signal of the first low pass filter is combined with an output signal of the high pass filter to produce the second signal.

10. A method for measuring defects of a sample, the method comprising:

resiliently clamping a sample between and in contact with a sound collector and a contact area of a jaw of a sample mounting fixture;

inducing vibrations in the sample fixed in the sample mounting fixture by applying an impact to the sample;

collecting sound induced in the sample in response to the impact with the sound collector; and

analyzing frequencies of the sound collected by the sound collector.

11. The method according to claim 10, wherein an area of the sound collector in contact with the sample is substantially the same as an area of the contact area of the sample mounting fixture in contact with the sample.

12. The method according to claim 11, wherein the jaw of the sample mounting fixture is movable in a direction opposite a direction of the impact applied to the sample and includes a cushioning material on the contact area.