Optical pickup apparatus and focusing control method
US7016269B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 20, 2001 |
| Grant date | Mar 21, 2006 |
| Priority date | — |
| Expiry date | Sep 22, 2022 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B2007/0013
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An optical pickup apparatus having an irradiation optical system for condensing a light beam on a track of a recording plane and a photodetection optical system for guiding return light to a photodetector to detect a focal error includes a holographic lens provided in the optical path of the return light for outputting 0-th and ±1st order diffracted lights based on the return light; an optical element provided in front of or behind the holographic lens for providing astigmatism; photodetectors for receiving the 0-th and ±1st order diffracted lights; and servo-signal generating operation circuits connected to the photodetectors for generating a first and second focus error signals having a first and second capture ranges based on the output signal of the photodetector.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.