Multi-layer magnetic tag
US6204766A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 21, 1999 |
| Grant date | Mar 20, 2001 |
| Priority date | — |
| Expiry date | May 21, 2019 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01V15/00
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A magnetic marker or tag is disclosed which comprises (a) a first magnetic material characterised by high permeability, low coercivity and a non-linear B-H characteristic; and (b) a second magnetic material which is capable of being permanently magnetised, said first and second magnetic materials being superimposed one on the other and advantageously being substantially coterminous. The second magnetic material is preferably of medium coercivity. Selected regions of said second magnetic material can carry magnetisation such as to magnetically divide the first magnetic material into a series of magnetically discrete zones, the length of said magnetically discrete zones and/or the lengths of said magnetised regions ("gaps") of said second material constituting elements of a code.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.