Magnetic media with permanently defined non-magnetic tracks and servo-patterns
US6153281A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 18, 1998 |
| Grant date | Nov 28, 2000 |
| Priority date | — |
| Expiry date | Feb 18, 2018 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/24355
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A magnetic medium has permanently defined boundaries between tracks and a consistent surface smoothness. The crystallographic structure of the magnetic medium is modified at the track boundaries, so the grains of the magnetic thin film permanently take on a relatively non-magnetic structure as compared to the grains of the magnetic thin film within the tracks. Servo patterns on the magnetic medium may be permanently defined at the same time the track boundaries are permanently defined. Laser ablation, laser heating to an amorphous structure, photolithography, perpendicular deposition, ion milling, reverse sputtering, and ion implantation can be used individually or in combination, with either the magnetic layer or the underlayer, to create the relatively non-magnetic areas.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.