ORGANIC POLYMER O-PLATE COMPENSATOR FOR IMPROVED GRAY SCALE PERFORMANCE IN TWISTED NEMATIC LIQUID CRYSTAL DISPLAYS FOR IMPROVED GRAY SCALE PERFORMANCE IN TWISTED NEMATIC LIQUID CRYSTAL DISPLAY

摘要

The compensator design of the present invention with a positive birefringent O-plate layer 100 allows for a significant improvement in the gray scale characteristics and contrast ratio of a liquid crystal display (LCD) over a wide range of viewing angles. An O-plate compensator comprising an organic liquid crystal polymer, and a manufacturing method thereof are disclosed. This compensator is a uniaxial birefringent thin film whose axis is oriented obliquely with respect to the surface of the film. (Note that the birefringent film can be weakly biaxial.) The oblique orientation of the liquid crystal director parallel to the anomalous axis of the film is due to the obliquely deposited SiO 2, liquid crystals such as mechanically rubbed alignment agents Is achieved by casting an organic thin film over a surface specially prepared for orientation. The film may be cast from a solution of liquid crystal polymer, or may be cast from a reactive liquid crystal monomer having a nematic phase. The solvent that can be used during the manufacturing process is evaporated and the organic thin film is maintained at its nematic phase temperature. If a reactive monomer is used, the film is photopolymerized. Alternative embodiments of organic O-plates include the use of smectic-A and smectic-C materials. Manufacturing techniques employing these materials are described.