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Clear to colored security film

  • US 6,045,894 A
  • Filed: 01/13/1998
  • Issued: 04/04/2000
  • Est. Priority Date: 01/13/1998
  • Status: Expired due to Term
First Claim
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1. A multilayer film comprising alternating layers of at least a first polymer and a second polymer;

  • the film appearing substantially clear at approximately a zero degree observation angle, and colored at at least one observation angle greater than a predetermined shift angle wherein the film comprises a series of layer pairs having optical thicknesses of between approximately 360 nanometers and approximately 450 nanometers.

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