ANTI-FERROELECTRIC LIQUID CRYSTAL COMPOSITION SHOWING REDUCED DETERIORATION IN RESPONSE AT LOW TEMPERATURE

摘要

PROBLEM TO BE SOLVED: To obtain an anti-ferroelectric liquid crystal composition capable of high- speed response and low-voltage drive by selecting an anti-ferroelectric liquid crystal composition which can be kept in an anti-ferroelectric phase even when stored at a specified high temperature and has a specified or lower response speed of an anti- ferroelectric liquid crystal at ordinary temperature. SOLUTION: There is provided an anti-ferroelectric liquid crystal composition containing 5-70 wt.% thiocarboxylic acid ester represented by formula II, such as a liquid crystal compound represented by formula I. This composition can keep its anti-ferroelectric properties even when stored at a temperature as high as 60-100 deg.C and has a response speedτr of 30μsec or below at which transition from an anti- ferroelectric phase to a ferroelectric phase occurs at 20 deg.C and a threshold voltage V2 of 24 V at 20 deg.C. The anti-ferroelectric liquid crystal shows a symmetrical hysteresis curve when a plus voltage and a minus voltage are applied thereto. V1 is defined as the voltage at which the relative light transmittance is 10% during the course of increasing a plus voltage, and V2 is defined as the threshold voltage at which the relative transmittance reaches 90% during the course of increasing a plus voltage. In the formula, m is 7-12; n is 2-8; and a carbon atom market with * is an asymmetrical one.