Common optical path interferometric gauge
US4627731A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 3, 1985 |
| Grant date | Dec 9, 1986 |
| Priority date | — |
| Expiry date | Sep 3, 2005 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01J2009/0226
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A common optical path interferometric gauge comprises an optical beam that is split into two beams. Both beams are modulated and recombined after introducing an optical path length difference greater than the coherence length of the optical source. The combined beam is guided along a common optical path and is subsequently split into reference and measurement beams. The measurement beam is guided along a measurement optical path that includes a moving workpiece surface. Both beams are recombined after interposing an optical path length difference therebetween so as to reestablish coherence between portions thereof, producing optical interference indicative of the surface movement.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.