Optical pick-up and optical information recording and reproducing apparatus
US8036091B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jul 12, 2010 |
| Grant date | Oct 11, 2011 |
| Priority date | — |
| Expiry date | Jul 12, 2030 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B2007/0013
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An optical pick-up which permits the relative position of a diffracting optical element and a photodetector to be adjusted by feedback control with signals which are generated when more than one kind of diffracted light differing in order is received, the diffracted light occurring as the reflected light from the optical disc is divided and diffracted by the diffracting optical element having multiple regions. The photodetector which detects the light beam passing through the central region of the diffracting optical element and generates RF signals is juxtaposed with sub-photodetectors, so that they receive reflected stray light from out-of-focus layers and perform computation to calculate the reflected stray light component which the RF signal detector receives, thereby detecting only the component of signals of the reflected light from a target layer.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.