| 摘要 |
A dual status marker for use with a magnetic-type EAS system has a signal-producing layer including at least one magnetic thin-film of high permeability and low coercive force such as permalloy, and a signal-blocking layer including at least one remanently magnetizable thin-film such as an Fe-Cr alloy. The remanently magnetizable thin-film or thin-films should have a total thickness at least equal to, and preferably at least twice, the total thickness of the magnetic thin-film or thin-films of high permeability. By doing so, the marker is more reliably deactivated when the signal-blocking layer is magnetized. For even greater assurance of deactivation, the signal-blocking layer should include more than one remanently magnetizable thin-film, thus giving it a squarer B-H loop and greater assurance against false alarms. <IMAGE> |
