Measurement apparatus
US4049965A · kind A · utility
12Cited by
7References
23Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Mar 6, 1975 |
| Grant date | Sep 20, 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 a shadow 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.