Direct over-write magneto-optical recording medium having multiple recording layers, and method of recording new information by directly overwriting pre-existing recorded information on such medium
US5282095A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 17, 1992 |
| Grant date | Jan 25, 1994 |
| Priority date | — |
| Expiry date | Mar 17, 2012 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B11/10584
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A magneto-optical recording medium on which new information can be directly over-written over pre-existing recorded information. Such medium comprises two magneto-optical recording layers which have a difference in Curie temperature in the range of 0.degree. C. -25.degree. C. and which are separated from each other by a metal layer for the transfer of heat, such as aluminum. Recording is effected by scanning the medium with a write spot produced by a pulsed laser beam concurrently with application of an external magnetic field which is modulated in accordance with the information to be recorded. The layers may have equal Curie temperatures if they behave thermally asymmetrically. At any scanning position of the write spot the scanned superposed local areas of the two recording layers are heated thereby above the Curie temperature of at least one of such layers and then permitted to cool while being subjected to the external magnetic field. This produces a frozen-in net magnetization in the scanned local area of one of the recording layers, which aids the external magnetic field in producing a similar frozen-in net magnetization of the superposed local area in the other recording la…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.