Magnetic recording medium and method for manufacturing the same
US5643686A · kind A · utility
17Cited by
7References
20Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Dec 15, 1994 |
| Grant date | Jul 1, 1997 |
| Priority date | — |
| Expiry date | Dec 15, 2014 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S428/90
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A fixed permanent pattern is used for identifying a magnetic recording medium and a high security against forgery or modification is obtained by a magnetic recording medium including a non-magnetic support and at least two magnetic layers formed on said support, characterized in that at least one of said at least two magnetic layers contains magnetic particles having a coercive force of 4,000 Oe or less dispersed in a binder and has a non-rewritable fixed signal which has been recorded by magnetic field generated by a signal recorded on one or more other magnetic layers under the influence of an orientation magnetic field.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.