Optical pickup and optical disc apparatus
US7965594B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 30, 2010 |
| Grant date | Jun 21, 2011 |
| Priority date | — |
| Expiry date | Jun 30, 2030 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B2007/0013
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
When recording/reproducing an optical disc having a recording layer of multi-layer structure, an unwanted optical beam reflected from a recording layer other than a target layer for recording/reproduction is incident on a photodetector to cause an unwanted disturbance component to leak to a detection signal, giving rise to a degradation in the quality of a tracking control signal. In an optical pickup apparatus, for suppression of the degradation, an optical element is mounted having a diffraction area for diffracting part of the optical beam and light receiving planes for sub-optical beams are provided each of which has a light shielding zone or dead zone of a predetermined width on its central sectioning line.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.