Optical pickup device with dual-mode drive mechanism
US5070494A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 3, 1989 |
| Grant date | Dec 3, 1991 |
| Priority date | — |
| Expiry date | Apr 3, 2009 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B13/04
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An optical pickup device for optically reproducing an information recorded on a recording medium of a magneto-optical disc or a write-only-read-many optical disc, includes a semiconductor laser, an objective lens for converging the laser light emitted by the laser on the recording medium, a photo-detector for detecting a light reflected from the recording medium, a beam splitter for leading the emitted light from the laser to the objective lens and for leading said light reflected by the recording medium to the photodetector, a first phase plate disposed between the beam splitter and the objective lens, a second phase plate disposed between the beam splitter and the photo-detector, and a rotator for rotate the first phase plate in such a manner than the beam splitter forbids to transmit the light reflected by the recording medium into the laser in a case where the recording medium is said write-only-read-many optical disc, and that the beam splitter allows to transmit the light reflected by the recording medium into the laser in a case where the recording medium is the magneto-optical disc.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.