The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Nov. 28, 1989
Filed:
Jan. 17, 1989
Russell W Church, Oakdale, MN (US);
Eugene C Heltemes, White Bear Lake, MN (US);
Minnesota Mining and Manufacturing Company, St. Paul, MN (US);
Abstract
A dual status marker for use in electronic article surveillance systems having an alternating magnetic field. The marker comprises a magnetic responder element having a central switching portion and flux collectors on each end which concentrate flux within the switching portion to ensure that the flux density therein is sufficient to generate an appropriate response. The marker is made dual status by providing magnetizable keeper elememts adjacent the flux collectors. When the keeper elements are magnetized, the associated field biases the flux collectors and inhibits magnetization reversal therein in response to an interrogation field, thereby preventing flux from the interrogation field from being concentrated in the switching portion of the responder element.