Optical instrument and measurement for measuring displacement of scale using different order diffraction of a diffraction grating
US5499096A · kind A · utility
7Cited by
5References
13Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Apr 13, 1994 |
| Grant date | Mar 12, 1996 |
| Priority date | — |
| Expiry date | Apr 13, 2014 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01D5/38
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
In an instrument and method for optically measuring a displacement of a scale which can achieve the noise elimination of returning light to a coherent light source, the scale and optical system are so constructed that an intersecting point of light fluxes radiated from the coherent light source and split into those fluxes by means of a first beam splitter is not present on a transmitting type diffraction grating and the incident lights (d, e) on a reflecting plate and the reflected lights (f, g) from the reflecting plate have no common use of the same light paths.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.