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Security markers for reducing receipt fraud

  • US 7,501,646 B2
  • Filed: 11/02/2005
  • Issued: 03/10/2009
  • Est. Priority Date: 06/26/2003
  • Status: Active Grant
First Claim
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1. A method of reducing receipt fraud, the method comprising:

  • illuminating a receipt;

    attempting to detect aspects of emission from one or more luminescent markers incorporated in a valid receipt in response to the illumination, wherein each of the one or more luminescent markers comprises a glass doped with one or more rare earth elements, and wherein the aspects of emission comprise a pre-defined rate of change of emission versus time and a pre-defined rate of change of emission versus wavelength comprising a unique luminescent signature assigned to a location at which a valid receipt is issued; and

    validating the receipt when the attempt is successful.

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