US Patent 7394997 - Anti-counterfeiting tag formed from nanoparticles

http://www.freepatentsonline.com/7394997.html

This is yet another patent claiming the use of nanoparticles/nanocrystal/quantum dots as barcode type indicia. Claim 1 reads:

1. An article of manufacture with anti-counterfeit properties comprising:

a consumable;

a plurality of taggant nanoparticles dispersed within the consumable, each taggant nanoparticle having at least one known physical characteristic; wherein the plurality of taggant nanoparticles comprise a predetermined combination of nanoparticles providing at least two different taggant physical characteristics of at least two different categories as a taggant code encoding product identification for the consumable so as to permit identification of the consumable; and

wherein a machine receiving the consumable is enabled upon the determination of the consumable as non-counterfeit as indicated by the taggant code.

Some prior art overlooked during the patent prosecution and which may be relevant to the claims of this patent include:

US Patent 6617583- "A novel encoding system and methods for determining the location and/or identity of a particular item or component of interest is provided. In particular, the present invention utilizes a "barcode" comprising one or more sizes of semiconductor nanocrystals (quantum dots) having characteristic spectral emissions, to either "track" the location of a particular item of interest or to identify a particular item of interest. " (from abstract)

US Patent 6633370-"Quantum dots, semiconductor nanocrystals and semiconductor particles used as fluorescent coding elements" (title)

US Patent 7077329- "Spectral coding by fluorescent semiconductor nanocrystals for document identification and security applications" (title)