Laser-ultrasonic non-destructive, non-contacting inspection system
US5585921A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 15, 1995 |
| Grant date | Dec 17, 1996 |
| Priority date | — |
| Expiry date | Mar 15, 2015 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N2291/0427
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A laser-ultrasonic inspection system is provided for on-line and off-line inspection of a workpiece. The system utilizes an optical acoustic wave generation and detection system with relatively high spatial resolution and which appreciably reduces the effects of parasitic acoustic coupling. An array of acoustic waves are generated in the workpiece by a short pulse optical transmitter bee with a beam geometry that is tailored to focus the acoustic waves at an inspection site in the workpiece. The acoustic waves that probe the inspection site are then detected by reflecting an optical read-out beam from a surface of the workpiece and optically interfering it with an optical reference beam. The geometry of the optical read-out beam is chosen such that the read-out beam only detects the acoustic waves that arrive from the inspection site (acoustic waves that arrive from other parasitic acoustic sources are out of phase with respect to each other and cancel out). A wavefront compensation system improves acoustic clutter rejection and also improves the signal-to-noise by compensating for phase and amplitude aberrations induced on the optical read-out beam by the optically rough surface o…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.