Optical pickup device capable of detecting stable error signal
US6636464B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 6, 2000 |
| Grant date | Oct 21, 2003 |
| Priority date | — |
| Expiry date | Apr 25, 2022 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B7/0912
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An optical pickup device employing a signal detection unit including a hologram element having a plurality of pattern regions for diffracting and/or focusing light reflected and incident from a recording medium, a photodetector having a plurality of light receiving regions for receiving and photoelectrically converting the light diffracted by the hologram element and a signal operation unit for generating a focus error signal and/or a track error signal from a signal detected from the photodetector. The optical pickup device can implement a stable servo operation even at deviations of the photodetector, a change in the wavelength of light emitted from the light source, and/or shift of focusing means such as an objective lens, and can record and/or reproduce high-density information on/from the recording medium.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.