Liquid crystal composition and electro-optic display device

Abstract

A chiral, nematic liquid crystal composition suitable to STN-LCD, having superior steepness, rapid response and being able to prevent occurrence of high order and low order domain of LCD, which composition contains as a first component, at least one compound expressed by the formula (1) ##STR1## as a second component, at least one compound expressed by the formula (2) ##STR2## and as a third component, at least one compound of benzonitrile group, ##STR3## and further having a chiral dopant as a fourth component. In the above formulas, R.sup.1 and R.sup.2 each represent a linear alkyl group of 1 to 10 carbon atoms, A and B each represent trans-1,4-cyclohexylene or 1,4-phenylene, and R.sup.3 represents a linear alkyl group of 1 to 10 carbon atoms, or a group wherein an optional --CH.sub.2 -- or two or more not adjacent --CH.sub.2 --s present in the above group are replaced by --O-- or --CH=CH--; X.sup.1 and X.sup.2 each independently represent H or F; C represents --COO--, --C.sub.2 H.sub.4 --, trans-1,4-cyclohexylene or 1,4-phenylene; and n represents 0 or 1, and as a fourth component, a chiral dopant in a quantity in which a ratio (d/p) of the thickness (d.mu.m) of a liquid crystal layer in a liquid crystal cell to be filled with the liquid crystal composition to the helical pitch thereof (p.mu.m) is 0.03 to 2.0.