Optical information recording/reproducing apparatus that produces verifying reproduction signals by executing a computation using detection signals of multi-divided detection surfaces of a photo-detector
US5768219A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 18, 1996 |
| Grant date | Jun 16, 1998 |
| Priority date | — |
| Expiry date | Oct 18, 2016 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B11/10595
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An optical information recording and/or reproducing apparatus includes an irradiating device including an objective lens, having a curved surface, for irradiating a recording light beam to a magnetooptical recording medium having at least two magnetic layers, which are a recording layer and a reproduction layer, and which are exchanged-coupled to each other, and a magnetic layer for controlling the exchange-coupling force to block the exchange-coupling force between the recording and reproduction layers, a device for applying an external magnetic field modulated according to an information signal to be recorded on the beam irradiated portion of the recording medium to record information on the recording layer and to orient magnetization of the reproduction layer in a direction parallel to the external magnetic field, a splitting device including a polarizing beam splitter for splitting at least light produced by a magnetooptic effect of the recording medium and light produced by diffraction at the curved surface of the objective lens, a detector including a multi-divided photodetector for respectively detecting the split light beams and a device for producing verifying reproduction…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.