Optical encoder having high resolution
US5812320A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Nov 21, 1996 |
| Grant date | Sep 22, 1998 |
| Priority date | — |
| Expiry date | Nov 21, 2016 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B27/4277
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
An optical encoder is provided which is not affected by fluctuation of wavelength of a light beam due to temperature change, without sacrificing resolution of measurement. The optical encoder comprises a light source emitting a light beam, a first grating to which the light beam emitted by the light source is directed, and a second grating to which light beams exiting from the first grating is directed. Additionally, displacement information obtaining means is provided for obtaining information for the displacement of one of the first and second gratings, the information being obtained according to a twice-diffracted beam and a twice-transmitted beam at the second grating. The twice-diffracted beam is generated from a diffraction beam generated at the first grating, and the twice-transmitted beam is a transmission beam which has been transmitted through the first grating.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.