Abstract: The invention discloses optically active liquid crystal compounds represented by the formulas [I], [II] and [III]: ##STR1## wherein R.sub.1 and R.sub.2 each represents an alkyl group of 4-18 carbon atoms, X represents O, COO or a single bond, and (A), (B), (C), (D) and (E) each represents ##STR2## in which l represents a halogen. The invention further discloses optically active liquid crystal compounds which are able to exhibit tristable states, represented by the formulas [IV], [V] and [VI]: ##STR3## wherein R.sub.1 ' and R.sub.2 ' each represents a straight chain alkyl group of 5-16 carbon atoms, X' represents O or COO and (A), (B), (C), (D) and (E), and l each has the same meaning as above.

Abstract: A composition of (R)-isomer and (S)-isomer of a liquid crystal compound represented by the formula; ##STR1## wherein X represents --O-- or a direct bond, Z represents a halogen-substituted alkyl group selected from a group consisting of --CF.sub.3, --CHF.sub.2, --CH.sub.2 F, --C.sub.2 F.sub.5, --CClF.sub.2, -CCl.sub.2 F, --CCl.sub.2 CF.sub.3, and --C.sub.3 F.sub.7, m represents an integer of from 1 to 20, n represents an integer of from 1 to 20, and * represents an asymmetric carbon, and the optical purity of said composition is high enough to exhibit optically tristable states in S*(3) phase when electric voltage is applied.

Abstract: A liquid crystal compound represented by the following formula; ##STR1## wherein R.sup.1 and R.sup.2 each represents an alkyl group having 3-20 carbon atoms, and X represents a group ##STR2## or --O--, or a single bond, and a liquid crystal composition exhibiting optically tristable states comprising the liquid crystal compound represented by the above formula and an antiferroelectric liquid crystal compound.

Abstract: An antiferroelectric liquid crystal compound represented by the following general formula (I): ##STR1## wherein R.sup.1 and R.sup.2 are each independently selected from the group consisting of alkyl groups having from 3 to 18 carbon atoms, Rf is a lower alkyl group or a fluorinated lower alkyl group, (A) and (B) are each independently selected from the group consisting of 1,4-phenylene, 4,4'-biphenylene, and 2,6-naphthalene which may be substituted at least with a halogen atom, and * shows an asymmetric carbon atom.

Abstract: A novel antiferroelectric liquid crystal compound is disclosed which is represented by the following formula: ##STR1## wherein R.sup.1 and R.sup.2 are independently selected from C.sub.3 -C.sub.18 alkyl groups, respectively, Rf is a lower fluoroalkyl group, X is a group selected from the group consisting of --O--, --COO--, --OCO--, and --CO--, or a single bond, (A) and (B) each is a group independently selected from the group consisting of phenyl, biphenyl, and naphthalene group which may be substituted with a halogen atom, and C having an asterisk indicates an asynunetric carbon atom. A process for producing the antiferroelectric liquid crystal compound is also disclosed.

Abstract: Disclosed are novel liquid crystal compounds containing a naphthalene ring, having an excellent light leaking ratio at tristable states, and represented by the following formula: ##STR1## wherein R.sub.1 is a C.sub.6 -C.sub.16 linear alkyl group or C.sub.6 -C.sub.16 linear alkoxy group, R.sub.2 is a C.sub.4 -C.sub.12 linear alkyl group, R.sub.3 is a C.sub.1 -C.sub.3 alkyl group or C.sub.1 -C.sub.3 haloalkyl group, and C having an asterisk indicates an asymmetric atom.The liquid crystal compounds are expected to find their applications in electrooptical devices and liquid crystal displays utilizing a S*.sub.(3) liquid crystal phase which shows tristable states.

Abstract: Liquid crystal compound of the formula ##STR1## wherein R.sub.1 and R.sub.2 each is a C.sub.1-18 alkyl group or an aralkyl group, R' is a haloalkyl group, X is --0--, --CO--, --COO-- or direct bond, Y is --COO--, --OCO-- or --CH.sub.2 O--, (A) and (B) each is ##STR2## and p and l each is zero or one.

Abstract: Liquid crystal compounds represented by the formula; ##STR1## in which Ra means an alkyl group of 1-20 carbon atoms or an alkoxy group of 1-20 carbon atoms; Rb means an aliphatic alkyl group, a branched alkyl group or an aralkyl group respectively of 1-20 carbon atoms, an alkoxy group of 1-20 carbon atoms, or an alkanoyl methyl group having 1-20 carbon atoms in the alkyl; ##STR2## Z means a fluorinated alkyl or a fluorinated haloalkyl; m is an integer of from 1 to 3; n is an integer of from 0 to 2 where when n is 0, Y is a single bond; and * shows an optically active center, which have a larger spontaneous polarization, high speed of response and good orientation, and show tristable liquid crystal phase.

Abstract: A liquid crystal compound represented by formula (I): ##STR1## wherein R.sub.1 represents an alkyl group having from 1 to 18 carbon atoms; R.sub.2 represents an optically active group represented by formula (II), (III) or (IV): ##STR2## wherein R.sub.3 represents a lower halo-alkyl group having from 1 to 2 carbon atoms; X represents --O--, --COO--, --OCO-- or a single bond; Y represents --CH.sub.2 O-- or --COO--; and Z represents --COO-- or --O--, l represents 0 or 1, provided that when l is 0, Y is a single bond; n represents an integer of from 1 to 18; and * indicates an optically active center. The compound exhibits three stable states of molecular orientation.

Abstract: The invention lies particularly in novel compounds represented by the general formula; ##STR1## in which Z means CF.sub.3, CHF.sub.2, CH.sub.2 F, CClF.sub.2, CCl.sub.2 F, CHCLF, CCl.sub.3, C.sub.2 F.sub.2 or a perfluoroalkyl group of 3 or more carbon atoms, m and n are same or different with each other and represent an integral of 1-20, which are ferroelectric and chiral smetic liquid crystals of a large spontaneous polarization, a high speed of response and a good orientation, and showing a liquid crystal phase of tristable state and an electoclinic effect to be used as a liquid crystal element superior in an image display response.

Abstract: Ferrelectric chiral smetic liquid crystal compound are provided which have the formula, for example ##STR1## wherein R is a C.sub.1-20 alkyl group.

Abstract: An optically active liquid crystal compound which is represented by the formula: ##STR1## wherein R.sub.1 and R.sub.2 each represents an alkyl or aralkyl group of 4-18 carbon atoms, R.sub.3 represents a haloalkyl group, X represents O, COO, OCO, CO or a single bond, Y represents COO, OCO, CH.sub.2 O or OCH.sub.2, Z represents COO or O, (A) represents a cyclic group shown by ##STR2## (B) represents a cyclic group shown by ##STR3## and l shows that the cyclic groups are substituted by at least one halogen atom.

Abstract: The invention lies in novel ferroelectric liquid crystal compounds particularly represented by the general formulae, having a good responsibility in relation to the applied electric field and a wide range of phase transition points inclusive of the room temperature so as to be useful alone as the liquid crystal material but also to be mixed with other liquid crystal compounds for expanding the phase transition points to a desired range and making the response speed of the liquid crystal composition faster. ##STR1## In the formulae, m and n are same or different with each other and represent an integral of 1-20.