Magnetic recording medium comprising protrusion on its surface and a plasma treated substrate and recording/reproducing method therefor
US4734810A · kind A · utility
11Cited by
2References
11Claims
0Family size
Assignee
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Key dates
| Filing date | Jul 24, 1985 |
| Grant date | Mar 29, 1988 |
| Priority date | — |
| Expiry date | Jul 24, 2005 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B5/73937
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A magnetic recording medium comprising a ferromagnetic metal thin film layer formed on one surface of a flexible non-magnetic substrate and primarily comprising cobalt and oxygen is improved in durability by treating the substrate with a plasma at a frequency of 10 kHz to 200 kHz, and providing the magnetic layer on the surface with protrusions having a height of 30 to 300 .ANG. at an average density of at least 10.sup.5 /a.sup.2 per square millimeter of the surface, provided that the magnetic recording medium is passed for recording/reproducing operation across a magnetic head with a gap having a distance a as expressed n .mu.m.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.