Multibit bimorph magnetic tags using acoustic or magnetic interrogation for identification of an object coupled thereto

摘要

A tag structure suitable for attachment to an object includes one or more bimorphs comprised of a thin strip of a magnetostrictive material attached to a thicker bar of hard magnetic material. The tag is preferably excited using either magnetic or acoustic fields, tuned to the resonance of the bimorphs. The excitation induces strain in the bimorph which causes mechanical vibrations in the bimorph which are sensed acoustically or magnetically, giving rise to a code. A device for detecting the output of the tag is provided along with a device for decoding the output from the detecting means thereby to identify the object.