Patent · US Expired

Electro-magnetic desensitizer

US5805065A · kind A · utility

14Cited by

6References

14Claims

0Family size

Assignee

Minnesota Mining and Manufacturing Company · US

Inventors

Werner Schwarz · Reinach, CH
Josef A. Graessle · Kaarst, DE
Peter J. Zarembo · Shoreview, US

Key dates

Filing date	Mar 18, 1993
Grant date	Sep 8, 1998
Priority date	—
Expiry date	Mar 18, 2013

Classification

Technology area (CPC G)Physics
CPC primaryG08B13/2411
WIPO fieldControl
WIPO sectorInstruments

Abstract

A magnetic security marker of an article surveillance system is deactivated by first determining the status of the marker by exposing it to the interrogating field. If the marker is active, a deactivation field is applied to the marker. The marker is again interrogated using the interrogating field and, if an active marker is detected, an incrementally increased deactivation field is applied. The marker is continually interrogated and, as long as an active marker is detected, the intensity of the field is incrementally increased until the field reaches a level effecting deactivation.

Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.