Rotary position encoder based on polarization
US12146771B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Jan 10, 2022 |
| Grant date | Nov 19, 2024 |
| Priority date | — |
| Expiry date | Mar 20, 2042 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01D5/345
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A rotary optical position encoder includes a source of a linear-polarized light beam, a polarization-sensitive detector, and a rotating retarder disposed for rotation between the source and the detector. The retarder is configured and operative to produce a polarized exit beam whose polarization state rotates at a rate greater than a rotation rate of the retarder, thereby for increased resolution over a similar encoder using a rotating polarizer element. In an example, when polarized light is incident upon a rotating half-wave retarder, the transmitted beam's polarization axis rotates at twice the rate of retarder rotation, resulting in an electrical detector output that varies four times per revolution. Resolution is improved accordingly, as a given detected increment at the output is produced by only one-half the physical rotation increment required for a simple polarizer.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.