Liquid Crystal Displays and Novel Optical Thin Films Enabled by Photo-Alignment

Abstract

Photo-alignment and photo-patterning of monomeric- and polymeric liquid crystals by the linear photo-polymerisation (LPP) technology enables novel molecular configurations in liquid crystal displays (LCDs) as well as a plethora of new thin-film optical elements on single plastic substrates. A molecular building block design of LPP photo-co-polymers with display-specific functional groups is depicted. Contrast and brightness of twisted nematic (TN)-LCDs are shown to markedly improve by combining photo-aligned multi-domain TN-LC-configurations with liquid crystal polymer (LCP) wide-view films. To illustrate the diversity of the LPP/LCP technology, the following photo-aligned new optical thin-film elements on plastic films are presented; colorless nematic wide-view films for TN-LCDs, ideally bright polarisation interference color filters which meet PAL/SECAM standards, as well as photo-aligned and photo-patterned linear polarizers. Photo-generated monomer and polymer liquid crystal devices are key to enable future complex plastic LCDs.