Surveillance system having magnetomechanical marker
US4510489A · kind A · utility
304Cited by
5References
32Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Apr 29, 1982 |
| Grant date | Apr 9, 1985 |
| Priority date | — |
| Expiry date | Apr 29, 2002 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S428/928
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
A magnetic article surveillance system marker is adapted, when armed, to resonate at a frequency provided by an incident magnetic field applied within an interrogation zone. The marker is an elongated ductile strip of magnetostrictive ferromagnetic material disposed adjacent to a ferromagnetic element which, upon being magnetized, magnetically biases the strip and arms it to resonate at said frequency. A substantial change in effective magnetic permeability of the marker at the resonant frequency provides the marker with signal identity.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.