Surveillance marker a magnetic article, Responder multi-directionally, dual state, which has a persistent state.

摘要

A DOUBLE INDICATOR STATE, MULTIDIRECTIONAL ANSWER (10) AS SHOWN IN FIGURE 1 FOR USE IN SYSTEMS ELECTRONIC SURVEILLANCE PRODUCTS, HAVING A MAGNETIC FIELD INSIDE AN ALTERNATIVE interrogation zone. The indicator comprises a part (12) of a high permeability magnetic material LOW coercive force substantially coextensive with a part (14) magnetizable material residually, in which the first part (12) is configured to have at least two RESPONSE AREAS elongated (16,18,20, and 22) ADJACENT TO THE EDGES OF PART PERPENDICULAR TO EACH AND EVERY REGION HAS AN AREA OF narrowness forming a switching section AMPLE AND ADJACENT REGIONS (24.26, 28 and 30) forming flux collectors. In a preferred presentation, Interns EDGES all regions are defined by a narrow band of removed material being magnetically ISOLATED AREAS IN ANSWER THE REMAINING MATERIAL its center. The indicator is desensitized STEP BY MAGNETIZATION UNIFORM MAGNETIC MATERIAL NO.