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Dual status magnetic marker having magnetically biasable flux collectors for us in electronic article surveillance systems

  • US 4,825,197 A
  • Filed: 02/01/1988
  • Issued: 04/25/1989
  • Est. Priority Date: 02/01/1988
  • Status: Expired due to Term
First Claim
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1. A dual status marker for use in an electronic surveillance system in which there is produced in an interrogation zone an alternating magnetic field, said marker comprising at least one piece of low coercive force, high permeability responder material configured to have at least one center section and flux collectors proximate to each end of each said center section and pieces of remanently magnetizable keeper material positioned proximate to at least certain of said flux collectors, whereby when said pieces of keeper material are magnetized, localized fields result which bias the magnetization in said certain flux collectors and results in an altered response of the marker to said applied field compared to that resulting when said pieces of keeper material are unmagnetized.

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