Photo-patterned e-wave polarizer

In this paper, we report our development in the photo-patterned e-wave pola rizer. This polarizer is prepared from amphiphilic dye molecules, which sel f-assemble and stack up to form the hexagonal complexes of lyotropic liquid crystals (LLC) under certain conditions. As a result, it gives rise to a h igh order parameter and a cylindrical symmetry. Along the c-axis of these c omplexes most of the e-wave is transmitted, whereas the o-wave, which propa gates on the plane orthogonal to this c-axis, can be absorbed effectively. However, the methods usually used to manufacture the e-wave polarizer are b ased on the mechanical shear flow, which causes unpleasant visual defects a nd has limited resolution. Therefore, we propose and demonstrate two novel fabrication methods to both photo-align and photo-pattern these e-wave pola rizers. The first method consists of transferring a well-prepared LLC polar izing film onto the substrate using the photocuring glue. The second method consists of applying a photo-alignment layer to induce a preferential orie ntation of the LLCs. The c-axis in this case is determined by the polarizat ion vector and the incidence plane of the actinic radiation. Since the loca l structure is patterned optically, the multi-axes and multi-colour polariz ers can be prepared cost-effectively. In addition, this photo-patterned pol arizing film, which is about 0.3-0.7 mum, can be coated on the internal or external substrate surfaces of a liquid crystal display (LCD). For the TN-L CD with the internal polarizers, we find that the electro-optic characteris tics are basically similar to those with the external polarizers. This is c entral to the internal polarizer development since the STN-LCD is sensitive to any voltage and thickness variations. (C) 2001 Published by Elsevier Sc ience B.V.