Information detection of a phase-change type optical recording medium by shifting the phase of a reference light
US5381395A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jun 1, 1993 |
| Grant date | Jan 10, 1995 |
| Priority date | — |
| Expiry date | Jun 1, 2013 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B7/0051
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A signal information recorded on a recording layer formed on a phase-change type optical disk is reproduced as a phase change. Laser light emitted from a laser light source is collimated to a reference light by a lens. The reference light is divided by a beam splitter into a first reference light and a second reference light. The first reference light is directed through a condenser lens to the recording layer of the optical disk. A reflection light from the recording layer is directed through the beam splitter and a second condenser lens to an optical detector. The second reference light is passed through a phase difference plate, a reflection mirror, the phase difference plate, the beam splitter and then through the second condenser lens to the optical detector as a phase shifted reference light. At an input end of the optical detector, the reflection light and the phase-shifted reference light interfere with each other and the signal information having substantially no phase jitter is obtained at an output of the optical detector.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.