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Embedded optical signatures in documents

  • US 20060180673A1
  • Filed: 03/29/2006
  • Published: 08/17/2006
  • Est. Priority Date: 12/19/2003
  • Status: Active Grant
First Claim
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1. A method of embedding an optical signature on a substrate, comprising the steps of:

  • embedding a first optical pattern on the substrate; and

    placing an invisible covering over at least a portion of the first optical pattern, the invisible covering fluorescing when exposed to one or more non-visible wavelengths of light.

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