Optical device for optically recording and reproducing information signals on an information carrier
US4507766A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 12, 1982 |
| Grant date | Mar 26, 1985 |
| Priority date | — |
| Expiry date | Jul 12, 2002 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B7/1356
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An optical device for optically recording and reproducing information in and out of a recording medium. The device consists of a movable optical system which carries out at least two-dimensional movements and a stationary optical system. The movable optical system includes a beam splitter adapted to receive a parallel light beam, an objective lens for focussing the light beam from the second beam splitter onto the medium and a photodetector disposed in the vicinity of the beam splitter and adapted to receive, through the objective lens and the beam splitter, the light beam reflected by the information carrier. The stationary optical system includes a beam splitter for directing the parallel light beam from the source to the beam splitter of the movable optical system and a photodetector for receiving the reflected light beam coming through the beam splitter. The photodetector of the movable optical system provides at least a tracking control signal while the photodetector of the stationary optical system provides at least a focussing control signal.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.