Disk apparatus for focusing and adjusting a laser beam
US6522605B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 30, 2000 |
| Grant date | Feb 18, 2003 |
| Priority date | — |
| Expiry date | Apr 28, 2021 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B7/094
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A disk apparatus includes a DSP core. When turning on power to the apparatus main body or exchanging the MO disk, setting processing of focus offset (offset) values is performed. The DSP core extracts fine clock mark (FCM) signals out of the reproduced signal through tracking on the land/groove. Specifically, in a range that mean value of FCM signal levels is equal to or greater than a predetermined level, FCM signal levels are detected at positions shifted left and right by a predetermined amount from a present offset value. In this manner, scanning is made throughout the range while being shifted by a predetermined amount, each time of which a difference is detected. An offset value where the difference assumes a minimum is determined as an optimal offset value. The optimal offset values are determined respectively for the land and the groove, which are switched according to a track (land/groove) upon reproduction.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.