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Security document having a security thread embedded therein and methods for producing and testing the authenticity of the security document

  • US 4,756,557 A
  • Filed: 12/23/1985
  • Issued: 07/12/1988
  • Est. Priority Date: 12/21/1984
  • Status: Expired due to Fees
First Claim
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1. A security document comprising at least one elongated security thread said security thread being at least partially embedded within said document, said thread being visually detectable in incident and/or transmitted light said security thread further comprising a plurality of areas extending homogeneously along the entire length of the thread, said areas differing in terms of their detectable physical properties and being arranged so that said detectable physical properties can be visually detected from a surface of said document.

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