Optical encoder with misalignment detection and adjustment method associated therewith
US8895911B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Jan 27, 2012 |
| Grant date | Nov 25, 2014 |
| Priority date | — |
| Expiry date | Aug 12, 2032 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01D5/38
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An optical encoder includes a scale having diffraction gratings formed at predetermined pitches in a measurement axis direction, a detection head relatively movable with respect to the scale, the detection head including a light source portion configured to irradiate the scale with light, and a plurality of receiver portions configured to receive light reflected by or transmitted through the diffraction gratings of the scale, at different phases, and a signal processing device configured to perform signal processing to light reception signals output from the receiver portions of the detection head, to produce quadrature differential signals. The signal processing device is configured to calculate alignment adjustment monitor signals corresponding to a Lissajous radius of the quadrature differential signals in order to detect misalignment of the detection head with respect to the scale.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.