Apparatus and method for phase-shifting interferometry
US6717680B1 · kind B1 · utility
17Cited by
3References
57Claims
0Family size
Inventors
Key dates
| Filing date | May 13, 2002 |
| Grant date | Apr 6, 2004 |
| Priority date | — |
| Expiry date | Oct 2, 2022 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01B2290/70
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
The invention extends and improves the basic technique of phase-shifting interferometry by minimizing the measurement errors introduced by additional unwanted reflections from surfaces and surface defects far from the surface of interest. The inventive phase shifting interferometer includes at least two independent phase shifters. The two phase shifters operate cooperatively to produce a particular desired cavity interference modulation frequency while the modulation frequency of interference produced from other sources is significantly altered.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.