Abstract: Chiral liquid crystal compounds for use as dopants to be mixed with a liquid crystal host material, which may or may not be composed of chiral molecules, to form ferroelectric liquid crystal compositions. The chiral liquid crystal compounds are represented by the following formula: ##STR1## wherein: R.sub.1 is a C.sub.2 to C.sub.10 alkyl group, R.sub.2 is a C.sub.2 to C.sub.8 alkyl group;A is either ##STR2## m is an integer of 1 or 2; n is an integer of 1 or 2;p and q are integers of 0 or 1, provided that when p=0, q=0, and p=1, q=1; and* and ** indicate, independently of each other, S- or R-stereoisomeric structure.

Abstract: Optically active compounds of general formulae ##STR1## wherein A is O or S, R.sub.1 is a hydrogen atom, an alkyl group having 1-22 carbon atoms, a hydroxy containing alkyl group, para-alkyl substituted phenyl, para-alkyl substituted biphenyl, hydroxyphenyl, hydroxybiphenyl or tosyl; R.sub.2 is an alkyl group having 2-8 carbon atoms; m is an integer of 0-5, n is 0 or 1, where when m=0, n is not 1; p is 0 or 1; q is 0 or 1; D and E are independently H or a halogen atom; R.sub.3 is a linear alkyl group having 1 to 22 carbon atoms; and * and ** are asymmetric centers.

Abstract: A liquid crystal composition containing an optically active or a ferroelectric liquid crystal compound represented by the following formula: ##STR1## wherein A can be either --CH.sub.2 -- or --CO--; R can be either an alkyl or alkoxyl group having 1 to 22 carbons: R' is an alkyl group having 2 to 8 carbons; x and y are integers of either 0 or 1, provided that when x=0, y.noteq.1; D can be a hydrogen or a halogen atom; and * represents a chiral center. The ferroelectric liquid crystals of the present invention exhibit optical and chemical stabilities, high-speed responsive, and high spontaneous polarization, and thus are excellent materials for use in making liquid crystal devices and liquid crystal light switching elements.

Abstract: An optically active lactic acid derivative having the formula (1a): ##STR1## wherein A is O or S; B is --(CH.sub.2).sub.m -- or --(CH.sub.2).sub.n --O; R1 is an alkoxy group having 1-22 carbon atoms, a phenolate, a substituted phenolate, a hydroxy group, or a halogen atom; R2 is an alkyl group having 2-8 carbon atoms; m is 0, 1, 2, 3 or 4; n is 2, 3, 4 or 5; C* is an asymmetric carbon atom. Liquid crystal compositions and liquid crystal devices containing the above mentioned derivatives are also disclosed.

Abstract: A liquid crystal composition containing an optically active or a ferroelectric liquid crystal compound represented by the following formula: ##STR1## wherein: A is selected from the group consisting of oxygen and sulfur; B is selected from the group consisting of --(CH.sub.2).sub.m -- and --(CH.sub.2).sub.n --O--; R is an alkyl or alkoxyl group having 1 to 22 carbons; R' is an alkyl group having 2 to 8 carbons or an ether group having 2 to 8 carbons; m is an integer from 0 to 4; n is an integer from 2 to 5; k is an integer of 0 or 1; l is an integer of 0 or 1; C and D are selected form the group consisting of hydrogen atom and halogen atoms, and * represents a chiral center. The ferroelectric liquid crystals of the present invention exhibit optical and chemical stabilities, high-speed switching characteristic and high spontaneous polarization, and thus are excellent materials for use in liquid crystal devices and liquid crystal light switching elements.