Patent ID: RE44254

Claim:
A method of identifying or detecting an object comprising the steps step of: (a) applying onto or into at least a portion of the object an effective amount of a photoluminescent composition comprising: (i) One one or more photoluminescent phosphorescent materials, and (ii) One one or more photoluminescent fluorescent materials; wherein the one or more photoluminescent phosphorescent materials selectively absorbs and emits electromagnetic energies when charged or activated by either electromagnetic radiation from an excitation source incident upon the composition, or by the emissions of another photoluminescent material, or both, wherein the one or more photoluminescent fluorescent materials selectively absorbs the emission from the one or more photoluminescent materials and emits the electromagnetic energies to give a selected emission signature, such that some or all of the emission signature lies in the infrared portion of the electromagnetic spectrum, the photoluminescent materials being selected so that the emission of one of the photoluminescent materials overlaps with the absorbance of another of the photoluminescent materials, and wherein the selected emission signature is the emission from one or more of the selected photoluminescent fluorescent materials, such emission being essentially unabsorbed by any of the other photoluminescent materials, (b) charging or activating the object wherein the photoluminescent composition enables the object to be subsequently charged or activated and identified or detected , and (c) detecting the emission signature being detected from the charged object.