Compatible optical pickup
US6337841B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 25, 1999 |
| Grant date | Jan 8, 2002 |
| Priority date | — |
| Expiry date | Oct 25, 2019 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B2007/13727
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A compatible optical pickup capable of recording or reproducing information on or from compact disc (CD) family media such as CD rewritable (CD-RW) and digital versatile disc (DVD) by adopting a stepped planar lens having a plurality of gratings. The compatible optical pickup includes a first optical source for emitting a first light beam having a predetermined wavelength; a second optical source for emitting a second light beam having a long wavelength relative to the first light beam; an optical path changing element for changing the traveling path of an incident light beam; an objective lens for condensing the first and second light beams onto optical discs having different thicknesses, respectively; an optical diffraction element having a first region which directly transmits the first and second light beams incident thereto, and a second region bounding the first region, which directly transmits the incident first light beam and diffractingly transmits the second light beam toward an optical axis; and a photodetector for detecting an information signal and an error signal from the first and second light beam which have been reflected by the optical discs and passed through the…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.