TFT-addressed cholesteric liquid crystal projection display

A TFT-addressing of Polymer-Stabilized Cholesteric Textures (PSCT) cell has been accomplished with a novel mixture of polymer and liquid crystal. To improve driving voltage and hysteresis width of the PSCT cell, we have investigated the effects of the molecular structure and morphology of polymer matrix on the electro-optical properties. A Scanning Electron Microscopy (SEM) analysis showed that the polymer in the PSCT cell formed fibrillar aggregated beads with a sub-micron order diameter. The distance between the neighboring fibrils directly affected the electro-optical properties of the PSCT cell. By controlling the distance of the fibril with poly(4,4'-bis-acryloyloxy-diethylstilbene), PSCT cell demonstrates an excellent properties, i.e., driving voltage (V-10) of 7.1 V, a contrast ratio of 18, a hysteresis width of 0.4 V, and a charge-holding ratio of 94%. An 8.9 inch color TFT-PSCT display panel was fabricated for overhead projection. The panel showed a light transmission 2.5 times as high as that of the ordinary TFT-TN (Twisted Nematic) display.