Cyclic error compensation in interferometric encoder systems
US8913226B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Dec 9, 2011 |
| Grant date | Dec 16, 2014 |
| Priority date | — |
| Expiry date | Sep 15, 2032 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F7/70775
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Methods and apparatuses for performing the same, where the methods include obtaining, from an interferometer, a time-varying interference signal S(t) based on a combination of a first beam and a second beam, the first beam being diffracted from an encoder scale, in which at least one of the encoder scale and the interferometer is moveable with respect to the other, obtaining one or more error correction signals based on one or more errors that modify the time-varying interference signal S(t), and outputting information about a change in a position of the encoder scale relative to the interferometer based on the time-varying interference signal S(t) and the one or more error correction signals.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.