Optical disk with magnetic layer separated magnetically between tracks and method of magnetically separating tracks of the optical disk
US6690626B2 · kind B2 · utility
Assignees
Inventors
Key dates
| Filing date | Apr 18, 2002 |
| Grant date | Feb 10, 2004 |
| Priority date | — |
| Expiry date | Apr 18, 2022 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B11/10578
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
On a disk-shaped substrate in which a predetermined region ranging in a radial direction is used as a data region for recording/reproduction, a first dielectric layer, a magnetic layer, and a second dielectric layer are provided. The data region includes recording/reproducing tracks composed of a plurality of discontinuous grooves or lands ranging from an innermost track to an outermost track. Magnetic anisotropy of each of magnetic layers positioned between the respective recording/reproducing tracks is reduced to a level lower than that of magnetic anisotropy of the magnetic layers positioned on the recording/reproducing tracks, so that the magnetic layers are magnetically separated only between the recording/reproducing tracks and not magnetically separated in flat portions without grooves. Thus, reflectance is even in the flat portions, thereby allowing tilt detection.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.