Systems and methods for absolute positioning using repeated quasi-random pattern
US6937349B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | May 2, 2003 |
| Grant date | Aug 30, 2005 |
| Priority date | — |
| Expiry date | Feb 20, 2024 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01D2205/90
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An absolute 2D position-sensing device is usable to measure the position of a first element with respect to a second element. A 2D absolute scale includes an integrated 2D absolute scale pattern extending over the 2D scale area along each measuring axis of the scale. The integrated 2D absolute scale pattern includes a predetermined quasi-random pattern repeatedly interleaved with a plurality of code portions along each axis. Each code portion includes a plurality of code elements indicative of an absolute measurement value. The offset of the quasi-random pattern relative to a readhead of the device is combined with the absolute measurement value to determine an absolute position to a very high resolution over a relatively large 2D range.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.