Patent ID: 8791439
Filing Date: 2014-07-29
Classification: C09K,F41J,G01J,G01N,G07D,H04N,Y10T

Abstract:
1. A method for authenticating and differentiating between a series of articles, the method comprising: applying to each article a security feature comprising a particulate composition comprising at least one particle having at least two different crystalline and/or glass phases, each phase comprising a host lattice and a dopant sensitive to electromagnetic radiation and the different phases simultaneously producing different responses on exposure to photons of the same energy, whereby the output from the particulate composition when exposed to said photons is the sum of the responses from the different phases; varying the ratio of the amounts of the different phases in the particulate compositions applied to the different articles whereby each article produces a different output on exposure to said photons of a given energy; exposing each article to on exposure to photons of said given energy; measuring the output from each article; and authenticating the articles.