Absolute encoder utilizing light of different wavelengths to reduce cross talk
US7732755B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 12, 2008 |
| Grant date | Jun 8, 2010 |
| Priority date | — |
| Expiry date | Nov 23, 2028 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01D5/34794
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An encoder having a code scale, an illumination system, and a plurality of photodetectors is disclosed. The code scale has a plurality of tracks that are illuminated by the illumination system. Each photodetector receives light from a corresponding one of the tracks and generates a signal indicative of a quantity of light received from that track. Each photodetector is limited to detecting light in a band of wavelengths corresponding to that track. Each track generates light in a band of wavelengths corresponding to that track, and the band of wavelengths corresponding to one of the tracks is different from the band of wavelengths corresponding to the tracks that are next to that track. The tracks can include alternating reflective and absorptive stripes, alternating transmissive and reflective stripes, or alternating luminescent and absorptive stripes.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.