Generation and detection of ultrasound with long pulse lasers
US5608166A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 12, 1995 |
| Grant date | Mar 4, 1997 |
| Priority date | — |
| Expiry date | Oct 12, 2015 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N2291/104
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A method and apparatus for generating and detecting ultrasound on a workpiece utilizing a long pulse laser. A modulated pulsed laser beam is directed at the workpiece. The pulse duration is defined to be the time of propagation of ultrasound from a generation location to a flaw or discontinuity to be detected within the workpiece and then to a detection location, or, the time of propagation of ultrasound directly from the generation location to the detection location. A second pulsed laser beam, having a pulse duration longer than the ultrasonic propagation time, is also directed at the workpiece. After receiving phase modulated light from second pulsed laser beam reflected or scattered by the workpiece, phase modulated light is demodulated to obtain a demodulation signal representative of the ultrasonic motion at the surface of the workpiece. The demodulation signal is then electronically processed.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.