Optical information recording/reproducing apparatus having focus error signal compensation
US6407968B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 23, 1998 |
| Grant date | Jun 18, 2002 |
| Priority date | — |
| Expiry date | Nov 23, 2018 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B7/0945
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A light spot detects a focus offset amount based on an amount of variation of a focus error signal when a light spot passes a boundary between a land section and a groove section adjacent to the land section on an optical disk. Specifically, an amount of variations in the focus error signal at a center of a land section at a time the light spot passes the boundary between the land and the groove adjacent to the land is detected as a focus offset amount, and an amount of variation in the focus error signal at a center of the groove section is detected as a focus offset amount for the groove sections, thereby providing an optical information recording/reproducing device which permits recording/reproducing information on and from a tracking area of an optical disk under just-in-focus conditions without increasing a cost of the device nor being affected by an error due to changes over time or variations in optical disks.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.