Optical pickup
US6353587B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 23, 1998 |
| Grant date | Mar 5, 2002 |
| Priority date | — |
| Expiry date | Dec 23, 2018 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B2007/0006
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A first light source of an optical pickup emits a first laser beam having a first predetermined wavelength. A second light source emits a second laser beam that substantially perpendicularly crosses the first laser beam and has a second predetermined wavelength different from the first predetermined wavelength. A holographic beam splitter is slopingly disposed where the laser beams cross. The holographic beam splitter has a hologram diffractive surface on one surface and a coating layer on another surface for being penetrated by and reflecting the laser beams at a first predetermined ratio. A flat beam splitter is arranged on a first path of the laser beams from the holographic beam splitter to be penetrated by and reflect the laser beams at a second predetermined ratio. A collimator lens is arranged on a second path of the laser beams from the flat beam splitter to shape the laser beams. An objective lens focuses the shaped laser beams at least upon an optical disc. A photodiode reads out recorded and error information from the laser beams when reflected from the optical disc.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.