Objective lens for different optical recording media and an optical pickup device utilizing it
US7266070B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 25, 2004 |
| Grant date | Sep 4, 2007 |
| Priority date | — |
| Expiry date | Dec 23, 2025 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B2007/0006
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An objective lens and an optical pickup device utilizing it are disclosed wherein the objective lens includes a specified aspheric surface profile having a discontinuity and a single specified diffraction optical surface so to provide a focusing effect which is usable with different optical recording media, such as a CD versus a DVD. By providing a single diffraction surface and an aspheric surface having a discontinuity, more freedom of design is achieved for the diffraction surface than would otherwise be possible. The objective lens according to the invention is designed so as to be both compact and inexpensive and enables recording/playback onto either type optical recording media using different wavelengths and different numerical apertures, depending on the recording medium used.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.