Magneto-optical recording medium having clock-marks on recording layer and apparatus for recording and reproducing same
US6388954B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 30, 1999 |
| Grant date | May 14, 2002 |
| Priority date | — |
| Expiry date | Mar 30, 2019 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B11/10543
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
The magneto-optical recording medium has a magnetic domain magnification reproducing layer and an information recording layer. Clock marks are formed on the information recording layer, making it possible to generate a reproducing clock on the basis of these. The clock marks are detected either by irradiating directly with light of wavelength &lgr;2(&lgr;1≠&lgr;2), being different from the light of wavelength &lgr;1 which is used for reproducing the recording marks, or by applying a direct-current magnetic field, transferring and enlarging the clock marks on to the magnetic domain magnification reproducing layer, and detecting the reproduction signals from this magnetic domain magnification reproducing layer. Since the reproducing clock is in exact synchronisation with the recording marks, it is eminently suitable as a clock for pulse-modulated reproducing light and reproducing magnetic fields used when reproducing the reproducing layer.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.