Photoelectric position-measuring arrangement having a plurality of shiftable grids
US5009506A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Mar 22, 1989 |
| Grant date | Apr 23, 1991 |
| Priority date | — |
| Expiry date | Mar 22, 2009 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01D5/38
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A position measuring arrangement is disclosed which comprises a three-grid measuring system. A first grid is illuminated under an angle .alpha.. Two partial beams result from diffraction on the first grid. the two partial beams impinge on a second grid, which may be the scale of the position-measuring arrangement. Diffraction of the partial-beams on the second grid result in four partial-beams of which the two partial-beams lying closest to the grid normal impinge upon a third grid. The third grid again diffracts the partial-beams and brings them into interference. The partial-beams which are intensity-modulated by interference by the third grid impinge upon photodetectors, by which they are transformed into phase-shifted electric signals and fed to and evaluated arrangement.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.