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Pattern metallized optical varying security devices

  • US 5,757,521 A
  • Filed: 11/21/1995
  • Issued: 05/26/1998
  • Est. Priority Date: 05/11/1995
  • Status: Expired due to Fees
First Claim
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1. A security device, comprising:

  • a substrate, one surface of which includes a surface relief pattern; and

    a metallic pattern disposed thereon in registration with the surface relief pattern, so as to amplify visibility of the surface relief pattern to an observer;

    whereinthe metallic pattern also forms a high frequency resonant structure.

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