Design and Applications of New Fluorinated Liquid Crystals of Fused Ring Systems for Active Matrix LCD

摘要

The thermal and physical properties of several new classes of fluorinated liquid crystals of fused ring systems are discussed. The fluorinated phenyl-decahydronaphthalenes have low birefringence and relatively high clearing points. The naphthalenes with four fluoro-groups, including a fluoro-substituent at C-1 position for the naphthalene ring, have large dielectric anisotropy, large birefringence and low visco-elastic ratio which leads to quick response time in a twisted nematic liquid crystal display (TN-LCD). The pentafluorinated tetraphydronaphthalene has large dielectric anisotropy with relatively low birefringence and exhibits good stability of nematic phase at low temperature. We have designed some liquid crystal mixtures for an active matrix LCD with advanced performance. The liquid crystal mixtures with low birefringence, sufficiently high voltage holding ratio and wide operating temperature range, which are suitable for a reflective liquid crystal display, have been achieved. The liquid crystal mixtures, which exhibit about 10 ms of quick response time for a TN-LCD and are suitable for TV, have been also achieved.