Optical head utilizing diffraction grating
US4817072A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 24, 1987 |
| Grant date | Mar 28, 1989 |
| Priority date | — |
| Expiry date | Jun 24, 2007 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B7/0956
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
In an optical type head device comprising a light source for emitting a light beam, a beam splitter, a condensor lens and a light detector for receiving said light beam for photoelectric conversion wherein a diffraction grating is provided to separate the light beam into a plurality of subbeams consisting of a zero-order subbeam and other subbeams so that a focussing error of the spot of the zero-order subbeam on an optical type data storing medium is detected by the fact that the light spot of the zero-order subbeam is deformed on the light detector, and a positional error of the spot of the zero-order subbeam with respect to a data track on the optical type data storing medium is detected depending on the position of the spots of the other subbeams.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.