Measurement apparatus
US4051367A · kind A · utility
24Cited by
7References
23Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Mar 6, 1975 |
| Grant date | Sep 27, 1977 |
| Priority date | — |
| Expiry date | Mar 6, 1995 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01D5/38
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
In an apparatus for measuring relative displacement between first and second members, a grating fixed relative to the first member is illuminated by means defining a spatially periodic optical object fixed relative to the second member. Light transmitted or reflected by the grating is detected by a system including means defining a spatially periodic light-receiving array fixed relative to the second member so as to interact with an interfernce image formed by the grating, the output of the detection system thus varying cyclically upon relative movement between the first and second members.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.