Microparticle taggant systems

摘要

A microparticle taggant having two or more distinguishable marker layers corresponding to a predetermined numeric code. The plurality of particles comprises a plurality of microparticle sets of at least one microparticle, each microparticle set is characterized by a specific marker layer combination different from each other microparticle set, and the combination of microparticle sets employed in said taggant collectively forms the numeric code. Each specific marker layer combination may employ two or more layers. The microparticle sets employed in the taggant may include at least one datum marker layer coded to include place information and at least two value marker layers coded to specify a value within the place, the datum marker layer(s) being readily distinguishable from the value marker layers and functioning to identify an orientation of the value marker layers.