Method and apparatus for writing and reading a magneto-optical record carrier
US5371721A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 28, 1992 |
| Grant date | Dec 6, 1994 |
| Priority date | — |
| Expiry date | Dec 28, 2012 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B11/10554
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A method and apparatus for writing and reading information in the form of a pattern of magnetic domains in an information layer of a record carrier. An optical scanning beam is focused to a diffraction-limited radiation spot, and a magnetic field is generated by a coil supplied with an energizing current the amplitude of which is modulated by the information signal to be recorded. The magnetic field is thereby modulated, and produces magnetic domains in the information layer such that each domain has a variable number of sub-domains and consequently a variable magnetization ratio, as determined by the information signal. This permits recording at an information density exceeding that corresponding to the size of the radiation spot.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.