Optical instrument for measuring displacement
US4676645A · kind A · utility
57Cited by
2References
9Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Nov 5, 1984 |
| Grant date | Jun 30, 1987 |
| Priority date | — |
| Expiry date | Nov 5, 2004 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01D5/38
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Optical instrument for measuring displacement comprising a movable diffraction grating used as a scale, a semiconductor laser device, photodetectors, and means for making two light beams diffracted by the diffraction grating interfere with each other in which displacement of said diffraction grating is measured, based on variations of interference signals. The laser device has a suitable coherency for making selectively two necessary light beams with equal optical path lengths interfere with each other.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.