Record carrier for a magneto-optical disc memory having guide grooves of a plurality of tracks disposed with a predetermined relation to light spot diameter
US4985881A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 21, 1987 |
| Grant date | Jan 15, 1991 |
| Priority date | — |
| Expiry date | May 21, 2007 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B7/24085
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A record carrier for recording, reproducing and erasing information. A circular disc-like substrate has a recording layer thereon such that information is written onto the recording layer by changing the direction of magnetization. A guide groove of a plurality of tracks is formed in advance and extends in the radial direction with flat portions therebetween. Each flat portion between the tracks of the guide groove is divided into a plurality of sectors, each of which includes a header portion in which a header signal containing an address for distinguishing at least a respective sector is formed in advance with pits of a phase structure and a data portion adjacent to the header portion. The guide groove serves as an optical guide for a light beam which records, reproduces and erases information onto the data portion.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.