Patent ID: 7867672
Filing Date: 2011-01-11
Classification: G03C

Abstract:
1. An image forming medium, comprising a substrate; an imaging layer comprising an imaging material coated on said substrate, wherein the imaging material exhibits a reversible transition between a colorless state and a colored state; and a protective layer over the imaging layer, the protective layer comprising dipolar molecules that can be reversibly switched between a UV light transmission state and a UV light absorption state, wherein the dipolar molecules in their random orientation absorb in substantially the same spectral region as the imaging material in its un-imaged state, the imaging layer is imageable by ultraviolet light when the dipolar molecules are in the UV light transmission state, but the imaging layer is substantially not imageable by ultraviolet light when the dipolar molecules are in the UV light absorption state, the dipolar molecules are dispersed in a film-forming medium for forming the protective layer, the film-forming medium is selected from the group consisting of a solvent, a polymer binder, microcapsules, and a matrix material, the dipolar molecules are compounds having an electron donor group and an electron acceptor group, connected by a conjugated path, and the conjugated path is selected from the group consisting of at least one aromatic ring conjugated through one or more ethenyl or ethynyl bonds having from 8 carbon atoms to 50 carbon atoms.