Optical pickup head and information recording/reproducing device
US6798723B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 4, 2002 |
| Grant date | Sep 28, 2004 |
| Priority date | — |
| Expiry date | Feb 26, 2023 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B2007/0013
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An optical pickup head is provided with a light source, a diffracting means for creating a plurality of diffracted beams, a converging means for focusing the diffracted beams onto an optical storage medium, a beam branching means for branching the plurality of beams reflected by the optical storage medium, and an optical detecting means for outputting a signal corresponding to the amount of light of the received beams. The optical detecting means has main beam light receiving portions and sub-beam light receiving portions. The amount of light of the first or higher order diffracted beams when they are substantially focused on and reflected by a focus plane of the plurality of information recording planes is equal to or greater than the amount of light of the zero order diffracted beam when it is reflected without focusing by a non-focus plane other then the focus plane of the plurality of information recording planes. The invention provides an optical pickup head where offset is not generated in the TE signals even during tracking with the objective lens when a two-layered disk is used.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.