Method of recording at least ternary data on optomagnetic recording medium having a plurality of magnetic layers
US4938915A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Mar 27, 1989 |
| Grant date | Jul 3, 1990 |
| Priority date | — |
| Expiry date | Mar 27, 2009 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B11/10586
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A method of recording at least ternary data on an optomagnetic recording medium having at least a first magnetic layer, and a second magnetic layer whose Curie temperature is higher than that of the first magnetic layer and which is capable of being magnetization inverted independently of the first magnetic layer, the method including the steps of aligning directions of magnetization of the first and second magnetic layers of the medium in a predetermined direction; and radiating a single light beam whose power is adjusted in accordance with the data so as to obtain one of a first level, a second level higher than the first level, and a third level lower than the first and second levels, while applying a bias magnetic field in a direction opposite to the predetermined direction, wherein only the direction of the first magnetic layer of the medium is inverted when a power of the light beam is in the first level, the directions of the first and second magnetic layers are inverted when the power of the light beam is in the second level, and the directions of the first and second magnetic layers are not inverted when the power of the light beam is in the third level.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.