US Patent 7349137 Polarizing, photochromic devices and methods of making the same

An optical element including:a substrate; andan at least partial coating having a first state and a second state on at least a portion of the substrate, the at least partial coating being adapted to be circularly polarizing or elliptically polarizing in at least one state and containing:a chiral nematic or cholesteric liquid crystal material having molecules that are helically arranged through a thickness of the at least partial coating; andat least one photochromic-dichroic compound that is at least partially aligned with the liquid crystal material such that a long axis of a molecule of the photochromic-dichroic compound is generally parallel to the molecules of the liquid crystal material.