Optical disk tracking method and device for producing a tracking error signal and a track crossing signal
US5828634A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 20, 1997 |
| Grant date | Oct 27, 1998 |
| Priority date | — |
| Expiry date | Feb 20, 2017 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B7/0903
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An optical disk device includes an optical system having a beam converting unit and an objective lens. The beam converting unit converts a beam of laser light emitted by a laser light source into a main beam and at least one sub-beam. The objective lens places a main spot on the disk by the main beam and at least one sub-spot on the disk by the sub-beam, such that, when the main spot is on a center line of one of lands and grooves of an optical disk, the sub-spot is between the center line of one of the lands and the grooves and a center line of an adjacent one of the lands and the grooves. A first unit produces a first push-pull signal from a reflection beam from the main spot on the disk. A second unit produces a second push-pull signal from a reflection beam from the sub-spot on the disk. A tracking error signal generating unit produces a tracking error signal based upon the first push-pull signal. A track crossing signal generating unit produces a track crossing signal based upon the second push-pull signal.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.