Angle measuring interferometer
US4717250A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Mar 28, 1986 |
| Grant date | Jan 5, 1988 |
| Priority date | — |
| Expiry date | Mar 28, 2006 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01B2290/70
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An angle measuring interferometer comprises a source (10) which emits a light beam containing two orthogonally polarized components of different frequencies; a source of a stabilized electrical reference signal (11) of a frequency corresponding to a difference frequency between the two components of the light beam; means, such as a tilted shear plate (16) or a beamsplitter/beam folder assembly (116, 116A) for converting the input beam into two separated, parallel, orthogonally polarized beams; a half-wave retardation plate (29A, 29) located in one of the separated beams for converting the two separated parallel orthogonally polarized beams into two separated parallel beams with the same polarization and frequency difference; means including a polarizing beamsplitter (44), for causing each of the separated different frequency parallel beams with the same polarization to be reflected once by each of two plane mirrors (71, 70) to produce two parallel output beams with the same polarization; a half-wave retardation plate (29B, 29) located in one of the separated parallel output beams, for converting the two separated parallel output beams of the same polarization into two separated par…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.