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US 7,922,936 B2Granted
Luminescent compositions, methods for making luminescent compositions and inks incorporating the same
AssigneeCabot Corporation
InventorsMark J. Hampden-Smith, Liam Noailles, Richard Anthony Einhorn, Darryl S. Williams
Life of this patent
Estimating the term…
Abstract
A particulate luminescent composition is disclosed that, when excited by electromagnetic radiation at a first frequency, emits electromagnetic radiation at a second frequency equal to or within 1500 cm−1 of the first frequency. The luminescent composition comprises substantially spherical particles having a weight average particle size of less than about 10 μm and a particle size distribution such that at least about 90 weight percent of the particles are not larger than twice the average particle size.
Claims30
A secure document, comprising:
- a document;
- and
- a security taggant comprising a powder batch comprising a luminescent composition that, when excited by electromagnetic radiation at a first frequency, emits electromagnetic radiation at a second frequency equal to or within 1500 cm−1 of the first frequency, wherein particles of said luminescent composition are substantially spherical.
A luminescent ink, comprising:
- (a) a liquid vehicle phase;
- and
- (b) a functional phase dispersed throughout the liquid phase, the functional phase comprising a powder batch comprising a luminescent composition that, when excited by electromagnetic radiation at a first frequency, emits electromagnetic radiation at a second frequency equal to or within 1500 cm−1 of the first frequency, wherein particles of said luminescent composition are substantially spherical.
Dependencies are inferred from the claim text.