Patent ID: 6466297
Filing Date: 2002-10-15
Classification: C09K,G02B

Abstract:
Method of preparing a broadband reflective polarizer comprising two or more layers of a polymerized mesogenic material with helically twisted molecular structure and planar orientation, wherein each of said layers is prepared by:a) blending a first mixture A comprising A1) a least one achiral polymerizable mesogenic compound, A2) optionally a polymerization initiator component, A3) optionally an organic solvent component, with a second mixture B1 comprising B1) at least one chiral polymerizable mesogenic compound, B2) optionally a polymerization initiator component, B3) optionally an organic solvent component, to obtain a chiral polymerizable mesogenic material; b) coating a layer of the blended mixtures A and B onto a first substrate or between a first and a second substrate, and aligning the chiral polymerizable mesogenic material in a planar orientation so that the axis of the molecular helix extends transversely to the layer; and c) polymerizing the aligned material and optionally removing the first and, if present, the second substrate from the polymerized layer, wherein in at least one layer the ratio of the blended mixtures A and B is different from at least one other layer and where in two or more of said layers are coupled together.