Study of Order Parameter of Liquid Crystal Mixture and Influence to Dichroic Ratio of Guest-Host System

摘要

High ordered liquid crystal (LC) mixture has been designed for high dichroic ratio guest-host (G-H) system. Good correlation between order parameter S of LC mixture and dichroic ratio has been confirmed. It is suggested that temperature index of S (β), which can be determined by measurement of the refractive index of LC mixture, and its neamtic-isotropic phase change temperature, T_(NI), should be optimized to increase dichroic ratio. Cyano-substituted LC materials have an advantage in the first compared with fluoro-substituted ones. The characterization of β and T_(NI) is useful to increase the contrast ratio of G-H liquid crystal displays.