Advances in liquid crystals for AM-LCD

Physical properties of mono-, di- and tri- fluorobenzene derivatives with different core structures consisting of 3-ring system were measured. By introduction of fluorine atoms, phase change temperatures decreased, nematic temperature range narrowed, optical anisotropy and elastic constant decreased, and dielectric anisotropy increased. From a calculation with MOPAC ver. 6.0, it is clear that elastic constants depend upon shapes of molecules under a restricted condition. By blending the investigated compounds as main components, different nematic mixtures, having low threshold voltage low viscosity,large optical anisotropy or wide nematic range, which an: suitable for specific applications for AM-LCD, were obtained.