Application of a photopolymer to a holographic reflector for reflective liquid-crystal displays

A photopolymer for fabrication of volume-type transmission holograms, which are used primarily on the holographic reflector for reflective LCD's, is r eported. This photopolymer consists of bisphenol-type epoxy resin and an ac rylic monomer with diaryliodonium salt and 3-ketocoumarin as a complex init iator. The chemistry of the imaging formation is based on the radical polym erization of the monomer initiated by a holographic exposure, followed by t he cationic polymerization of epoxy resin by UV exposure after postexposure baking. The yellowish color of the hologram derivatives that resulted from the sensitizing dye and hom the photospeed were improved to satisfy the sp ecifications for the holographic reflector. The holographic reflector now g ives brighter images. (C) 1999 Optical Society of America OCIS codes: 090.0 090, 090.2890, 090.2900.