Method of manufacturing perpendicular magnetic recording floppy disk
US4680197A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 2, 1985 |
| Grant date | Jul 14, 1987 |
| Priority date | — |
| Expiry date | Dec 2, 2005 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/31786
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A method of manufacturing a perpendicular magnetic recording floppy disk is disclosed. A first magnetic recording layer is formed by sputtering a perpendicularly magnetizable material on one side of a plastic film substrate. A second magnetic recording layer is formed by sputtering the perpendicularly magnetizable material on the other side of the plastic film substrate after forming the first magnetic recording layer. The second magnetic recording layer has a thickness greater than that of the first magnetic recording layer, when a curl of the first magnetic recording layer on the plastic film substrate, resulting from forming the first magnetic recording layer on the plastic film substrate, is to the outside. On the other hand, the second magnetic recording layer has a thickness lower than that of the first magnetic recording layer, when a curl of the first magnetic recording layer on the plastic film substrate is to the inside.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.