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Identification matter

  • US 4,500,116 A
  • Filed: 07/14/1980
  • Issued: 02/19/1985
  • Est. Priority Date: 01/18/1978
  • Status: Expired due to Term
First Claim
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1. An article for establishing personal identity, comprising a substrate carrying identification markings, said substrate having thereon or therein a phosphorescent material comprising a rigid matrix in which there are dispersed two or more organic phosphorescense activators which are unresponsive to visible light and which during and after irradiation with ultraviolet light emit visible phosphorescense, said matrix being transparent to radiation at the excitation and emission frequencies of said phosphorescense activators, said emissions of said phosphorescense activators differing from one another with respect to both wavelengths and lifetime, whereby the total emission of said phosphorescent material after cessation of said irradiation changes from an initial colour representing the combined emissions of said activators to a final colour representing the emission of that activator having the longest phosphorescence lifetime.

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