Position sensor with grating to detect moving object with periodic pattern
US6723980B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Jul 16, 2001 |
| Grant date | Apr 20, 2004 |
| Priority date | — |
| Expiry date | Jul 16, 2021 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01D5/366
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An optical track sensing device, and in particular to an optical sensor for detecting optical tracking information on a moving medium (or stationary medium and moving sensor). The sensing device relies on self-imaging, rather than optics, and obtains a very acceptable detected signal at other than the self imaging plane of the reflection off a moving medium. This provides more flexibility in the placement of the sensor, while still allowing the elimination of optical components by relying on self-imaging instead. In addition, by providing a pattern over the photodetector with a smaller period, higher frequency harmonics are detected, allowing more precise detection of the position of the medium. In one embodiment, the period of the detector pattern is selected to detect the higher harmonics of the grating on the moving medium.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.