Optical information recording/reproducing apparatus having a composite prism with a plurality of emission surfaces
US5793725A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 1, 1996 |
| Grant date | Aug 11, 1998 |
| Priority date | — |
| Expiry date | Nov 1, 2016 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B11/10597
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An optical information recording/reproducing apparatus records information on and/or reproduces information from an optical recording medium and detects a focal error based on a reflected light beam from the optical recording medium. The apparatus includes a composite prism which deflects a part of the reflected light beam to at least two positions excluding a central part of the reflected light beam, and a photodetector device having a plurality of photodetectors which respectively detect the deflected parts of the reflected light beam and output detection outputs. The focal error is detected based on the detection outputs of the photodetector device.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.