Optical disc readout method and apparatus with focusing
US6813229B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Apr 12, 2000 |
| Grant date | Nov 2, 2004 |
| Priority date | — |
| Expiry date | Apr 12, 2020 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B7/14
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An optical system including an objective lens applies five light beams (31 to 35) generated by an optical pickup to a plurality of adjacent tracks on a signal plane of a CD-ROM. Light beams reflected from the signal plane are detected with photodetectors (PD1, to PD6), and in accordance with the detection outputs of the photodetectors (PD1 to PD5), a record data read system reads at the same time data recorded on respective tracks applied with the light beams (31 to 35), and outputs to read data in the record order of CD-ROM by preventing the read data from being duplicated or omitted. Prior to reading record data, a system controller performs an offset bias adjustment of a focus servo system.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.