Magnetic recording medium and method for production thereof
US5169703A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 8, 1991 |
| Grant date | Dec 8, 1992 |
| Priority date | — |
| Expiry date | Jul 8, 2011 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/24372
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A magnetic recording medium having minute irregularities on the surface of a magnetic layer is disclosed. The value of the ratio A.sub.V /A.sub.P, where A.sub.V and A.sub.P are cross-sectional areas of valleys and projections as measured in a plane lower by 50 nm and in a plane higher than 50 nm than an intermediate plane of the magnetic layer, respectively, with the measurement being made using a three-dimensional roughness meter, is given by A.sub.V /A.sub.P .gtoreq.0.90, wherein the intermediate plane is a plane for which the cross-sectional area of the projections is approximately equal to that of the valleys. The minute irregularities on the surface of the magnetic layer are produced by providing a non-magnetic substrate presenting different surface roughnesses on its front surface and back surface, and by transferring surface irregularities constituting the surface roughness of the back surface of the non-magnetic substrate to the front surface of the substrate.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.