Multiple-beam holographic optical pick-up head
US6369377B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Jul 13, 2000 |
| Grant date | Apr 9, 2002 |
| Priority date | — |
| Expiry date | Jul 13, 2020 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B7/14
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
The present invention discloses a multiple-beam holographic optical pick-up head, which has the advantages of the multiple-beam optical pick-up head and the holographic optical pick-up head and can increase the light usage efficiency. This invention uses the property that a polarized diffractive optical element can generate different optical effects for laser beam with different polarizations and places a polarized multiple-beam grating and polarized hologram on the optical path for splitting the incident light toward the disc into multiple reading beams by the multiple-beam grating. The returning laser beams reflected from the disc are diffracted and diverted by the hologram to reach a photodetector. Both the incident and reflective beams are diffracted once only; thus the light usage efficiency can be increased.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.