Optical pickup apparatus and optimal light spot focusing method
US7280458B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Apr 12, 2002 |
| Grant date | Oct 9, 2007 |
| Priority date | — |
| Expiry date | Nov 26, 2023 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B2007/0006
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An optical pickup apparatus includes a first light source to emit a first light beam having a predetermined wavelength, a first optical path changer to change a proceeding path of the first light beam, an objective lens to focus the first light beam on a recording medium, a diffraction member to divide the first light beam reflected by the recording medium into five light regions, the diffraction member having a first diffraction region having a wide width in a direction corresponding to a tangential direction of the recording medium and second through fifth diffraction regions sequentially arranged around the outside of the first diffraction region in a direction corresponding to a radial direction of the recording medium, and a first photodetector having first through fifth light receiving portions to receive the first light beam reflected by the recording medium.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.