Photo Alignment and Patterning of Liquid Crystal Polymer Films and Optical Devices by Side-Chain Photopolymers

Prerequisite for virtually all nematic field-effects on which liquid crystal displays (LCDs) are based is stable, uniaxial surface alignment with defined bias tilt angle between the long liquid crystal (LC) axes and their display boundaries. Since the invention of the TN-LCD [1] in 1970 until recently this was achieved by confining liquid crystals between mechanically brushed surfaces [2–4]. We have first shown in the 1990s that, non-mechanical, uniaxial, tilted and patterned LC-alignment is possible by anisotropic Van der Waals surface interactions [5], namely by directional polymerization of photo-sensitive side-chain polymers films [5, 6] by linear polarized UV light. The LPP model is reviewed and its applications enabling high resolution multi-domain liquid crystal displays operated in transmission and reflection are discussed. Examples are given for optical retarders integrated into LCDs, anisotropic liquid crystal polymer (LCP)-films for 3D imaging, interference color filters, wide-view films and an...