Hologram optical pick-up using two laser sources
US5894464A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 24, 1997 |
| Grant date | Apr 13, 1999 |
| Priority date | — |
| Expiry date | Sep 24, 2017 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B2007/0006
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A hologram optical pick-up device using a first and second laser sources emit laser beams having different wavelengths, which are then focused by an objective lens on a disc, and reflected at a surface of the disc. The reflected laser beams are diffracted by a first hologram or a second hologram, and then received by a first photo detector or a second photo detector. Accordingly, a laser beam having an adjustable wavelength according to a thickness and a recording surface of the disc is emitted by the first laser source or the second laser source in order compensate the aberration of the laser beam due to the thickness of the disc. Thereby, the same hologram optical pick-up device can reproduce data from discs having different recording surfaces without loss of data. Also, the hologram optical pick-up can record and reproduce data on/from any disc with an increased efficiency of the laser beam.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.