Patent ID: 7439009

Claim:
A homogeneous medium selectively differentiable by selective exposure to radiation, the medium consisting essentially of: a binder; a liquid monomer contained within said binder, said monomer being photopolymerizable into a solid photopolymer; a dye contained within said binder, wherein said monomer is substantially homogeneously doped with said dye; wherein said dye is photoexcitable to bind to the photopolymer; wherein said monomer and said dye are selected and configured such that selective exposure of regions of the medium by radiation provides at least polymerization of said monomer, migration of said dye, and fixing of said dye; wherein, after the selective exposure, the photopolymerization selectively progressively solidifies the photopolymer, while, simultaneously, molecules of said dye migrate to photopolymerized regions and then become fixed in position by the photopolymer; wherein, after the selective exposure, a concentration gradient of said dye in the medium from unexposed to exposed regions results due to diffusion of said dye from unexposed to exposed areas; wherein, after the selective exposure, the medium becomes selectively differentiated in that dye concentration is increased in exposed areas relative to unexposed areas wherein said dye is fluorescent.