Compact optical pick-up head employing non-diffractive element
US6341116B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 16, 1999 |
| Grant date | Jan 22, 2002 |
| Priority date | — |
| Expiry date | Aug 16, 2019 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B7/1365
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A compact optical pickup head which doesn't utilize a holographic optical element is disclosed. A birefringent prism and a quarter-wave plate are disposed in the optical path of the compact pickup head. The birefringent prism is consisted of two crystals made from a birefringent material, and having their optical axes perpendicular to each other. Therefore, the laser source beam will not be refracted when passing through the birefringent prism or will be refracted to a direction differing from the returning beam), while the returning beam is refracted by the birefringent prism to the photo detector. The power of laser ray is fully utilized to increase the reliability of signal transformation. A higher optical signal can be obtained, and the interference of returning beam to the source beam is also be prevented.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.