Optical encoder
US7470892B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 5, 2004 |
| Grant date | Dec 30, 2008 |
| Priority date | — |
| Expiry date | Aug 20, 2024 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01D5/38
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An optical encoder includes an incoherent light source; a first grating, which is an amplitude grating having a first grating period, for spatial amplitude modulation of the incoherent light from the light source; a second grating, which is a phase grating having a second grating period, for spatial phase modulation of light from the first grating; a third grating, which is an amplitude grating having a third grating period, for spatial amplitude modulation of light from the second grating; and a light detecting element for detecting light from the third grating. The encoder detects relative displacement between the respective gratings. The optical transfer function from the light source to the light detecting element is enhanced, and the efficiency in utilizing light is improved.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.