DVD reading-writing pick-up head employing multiple wavelengths
US6370104B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 16, 1999 |
| Grant date | Apr 9, 2002 |
| Priority date | — |
| Expiry date | Aug 16, 2019 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B2007/0006
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
This invention relates to a DVD reading-writing pickup head employing multiple wavelengths for data access on an optical record medium. With the configuration of the pickup head of the present invention, the number of the used optical elements is minimized. The pickup head of the present invention includes a cemented birefringent prism, a plurality of objective lenses, quarter-wavelength plates and laser sources and a photo detector. The cemented birefringent prism is used to refract the laser beams generated by the laser sources into an incident branch and split the laser beams and a reflected branch reflected from the optical record medium.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.