Method and device for timely outputting focusing completion signal to realize focusing condition of optical pickup head
US7035176B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Sep 20, 2002 |
| Grant date | Apr 25, 2006 |
| Priority date | — |
| Expiry date | Jun 30, 2024 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B7/08511
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A method is provided for outputting a focusing completion signal to realize a focusing condition of an optical pickup head for an optical access apparatus. The method is described as follows. A trace shift of the optical pickup head along a focusing direction is actuated in response to a focus control signal when a focus adjustment operation starts. Then, a focusing error signal and a sub-beam addition signal are generated in response to optical signals from the optical pickup head. A closed-loop enable signal is generated to enable a closed-loop control operation in response to a specified situation of the focusing error signal. The focusing completion signal is outputted when the sub-beam addition signal is at a level greater than a threshold value and when the closed-loop enable signal is generated.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.