Optical disc apparatus and defocus correcting method
US8120999B2 · kind B2 · utility
0Cited by
6References
12Claims
0Family size
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Key dates
| Filing date | Apr 26, 2010 |
| Grant date | Feb 21, 2012 |
| Priority date | — |
| Expiry date | Apr 26, 2030 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B7/0908
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An optical disc apparatus in which a bias of a focusing error signal is changed to a value according to a recording power at timing corresponding to a predetermined address position before starting the recording and a defocus of an opposite polarity is preliminarily caused so as to set off a defocus which occurs at the start of the recording.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.