Focus servo circuit for a magneto-optical disk recording and reproducing apparatus
US5263009A · kind A · utility
7Cited by
7References
5Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Jul 29, 1991 |
| Grant date | Nov 16, 1993 |
| Priority date | — |
| Expiry date | Jul 29, 2011 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B7/0945
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An apparatus for optically recording/reproducing data to/from a disc including a focus servo circuit which initially sets an objective lens of an optical head to a predetermined setting. This predetermined setting is such that a laser beam passing through the lens is focused on the disc at a point inside of the disc in the thickness direction. Then, the focus servo circuit fine tunes the objective lens position until the laser beam is focused onto a recording film located inside of the disc.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.