Dual surface interferometer
US4334778A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 12, 1980 |
| Grant date | Jun 15, 1982 |
| Priority date | — |
| Expiry date | Sep 12, 2000 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01B2290/70
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A double-pass interferometer is provided which allows direct measurement of relative displacement between opposed surfaces. A conventional plane mirror interferometer may be modified by replacing the beam-measuring path cube-corner reflector with an additional quarter-wave plate. The beam path is altered to extend to an opposed plane mirrored surface and the reflected beam is placed in interference with a retained reference beam split from dual-beam source and retroreflected by a reference cube-corner reflector mounted stationary with the interferometer housing. This permits direct measurement of opposed mirror surfaces by laser interferometry while doubling the resolution as with a conventional double-pass plane mirror laser interferometer system.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.