Abstract: A ferroelectric liquid crystal device comprises:a pair of substrates comprising electrodes for applying a voltage, the pair of substrates having been subjected to a uniaxial orientation treatment, and being oriented at a distance opposite to each other such that the uniaxial orientation axes cross each other at a predetermined angle; the display device further comprising a liquid crystal material disposed between the exhibiting at least two stable states and pair of substrates, the liquid crystal material having a cone angle, a pretilt angle, a tilt angle and an apparent tilt angle, wherein:the liquid crystal material having an orientation state which satisfies the conditions represented by.THETA.<.alpha.+.delta.,.delta.<.alpha., and .THETA.>.THETA..sub..alpha. >.THETA./2in which .THETA. denotes the cone angle, .alpha. denotes the pretilt angle, .delta. denotes the tilt angle and .THETA..sub..alpha.

Abstract: A ferroelectric chiral smectic liquid crystal composition, comprising at least one compound represented by the following formula (I): ##STR1## wherein R.sub.1 denotes a linear or branched alkyl group having 1-18 carbon atoms capable of having a substituent, R.sub.2 denotes a linear or branched alkyl group having 1-12 carbon atoms; X.sub.1 denotes a single bond, ##STR2## and at least one compound represented by the following formula (II): ##STR3## wherein R.sub.3 and R.sub.4 respectively denote a linear or branched alkyl group having 1-18 carbon atoms capable of having a substituent, at least one of R.sub.3 and R.sub.4 being optically active; and X.sub.2 and X.sub.

Abstract: A liquid crystal device, comprising: a pair of substrates, and a ferroelectric liquid crystal disposed between the substrates, each of the substrates having thereon an electrode for applying a voltage to the liquid crystal and a uniaxial alignment film provided with a uniaxial alignment axis, the alignment films on the pair of substrates being substantially parallel with each other and having an identical axis direction; wherein the ferroelectric liquid crystal is disposed in such an alignment state that the liquid crystal shows a pretilt angle .alpha., a cone angle H, an inclination angle .delta. of SmC* layer, and an apparent tilt angle .theta. a satisfying relationships of: H<.alpha.+.delta. and H>.theta.

Abstract: A ferroelectric chiral smectic liquid crystal composition, comprising at least one compound represented by the following formula (I): ##STR1## wherein R.sub.1 and R.sub.2 respectively denote a linear or branched alkyl group having 1-18 carbon atoms capable of having a substituent, at least one of R.sub.1 and R.sub.2 being optically active; and X.sub.1 denotes a single bond, --O--, ##STR2## and at least one compound represented by the following formula (II): ##STR3## wherein R.sub.3 and R.sub.4 respectively denote a linear or branched alkyl group having 1-18 carbon atoms capable of having a substituent; X.sub.2 and X.sub.3 respectively denote a single bond, --O--, ##STR4## and m and n are respectively 0, 1 or 2 with proviso that m+n=2 or more.

Abstract: A liquid crystal device with a decreased temperature-dependence of response speed is obtained by using a liquid crystal composition having a temperature range where the composition assumes chiral smectic C phase. The temperature range of chiral smectic C phase includes a) a first temperature range where the liquid crystal composition shows a cone angle in chiral smectic C phase which increases on temperature decrease down to a mediate temperature, and b) a second temperature range, below the first temperature range, where the liquid crystal composition shows a cone angle in chiral smectic C phase which decreases on further temperature decrease below the mediate temperature.

Abstract: A liquid crystal composition comprising at least one mesomorphic compound represented by the following formula (I): ##STR1## wherein R.sub.1 and R.sub.2 respectively denote a linear or branched alkyl group having 1-16 carbon atoms optionally substituted; Z.sub.1 denotes a single bond, --O--, --COO-- or --OCO--; X.sub.1 denotes halogen; and A.sub.1 denotes a single bond or ##STR2## and at least one mesomorphic compound represented by the following formula (II): ##STR3## wherein R.sub.3 and R.sub.4 respectively denote an alkyl group having 2-16 carbon atoms optionally substituted; Y.sub.1 denotes a single bond, ##STR4## Z.sub.2 and Z.sub.3 respectively denote a single bond, --O--, ##STR5## A.sub.2 and A.sub.3 respectively denote a single bond, ##STR6## X.sub.2 and X.sub.3 respectively denote hydrogen, F, Cl, Br, --CH.sub.3, --CN or --CF.sub.3 ; and k is 0 or 1 with the proviso that Z.sub.2 is a single bond when A.sub.2 is a single bond, and Z.sub.3 is a single bond when A.sub.3 is a single bond and k is 0.

Abstract: A liquid crystal composition, comprising: at least one mesomorphic compound represented by the following formula (I): ##STR1## and at least one mesomorphic compound represented by the following formula (II):R.sup.3 --X.sup.3 --A.sup.2 --B--A.sup.3 --X.sup.4 --R.sup.4(II),The liquid crystal composition is easily aligned by a simple rubbing method to provide a uniform monodomain and further provides wider driving voltage and temperature margins effective for providing a practical ferroelectric liquid crystal device.

Abstract: A liquid crystal composition, comprising: at least one mesomorphic compound represented by the following formula (I):R.sup.1 --X.sup.1 --A.sup.1 --B--A.sup.2 --X.sup.2 --R.sup.2(I)and at least one mesomorphic compound represented by the following formula (II): ##STR1## The liquid crystal composition is easily aligned by a simple rubbing method to provide a uniform monodomain and further provides wider driving voltage and temperature margins effective for providing a practical ferroelectric liquid crystal device.

Abstract: A mesomorphic compound represented by the following formula (I): ##STR1## wherein R.sub.1 and R.sub.2 respectively denote a linear or branched alkyl group having 1-16 carbon atoms capable of having a substituent; Y.sub.1 denotes --COO--, --OCO--, --CH.sub.2 --or --OCH.sub.2 --; Z.sub.1 denotes a single bond, --O--, --COO--, --OCO-- or --OCOO--; and X denotes a halogen, cyano group or methyl group.

Abstract: A liquid crystal composition, comprising: at least one mesomorphic compound represented by the following formula (I): ##STR1## wherein R.sup.1 and R.sup.2 independently denote a linear or branched alkyl group having 1-18 carbon atoms capable of including one or non-neighboring two or more methylene groups which can be replaced with at least one species of --O--, --CO--, --COO--, --OCO--, --OCOO-- or --CH(X)-- with the proviso that --O-- cannot directly be connected to --O-- and X denotes halogen; Z.sup.1 denotes --COO-- or --CH.sub.2 O--; X.sup.1 and X.sup.2 independently denote a single bond, --O--, --COO--, --OCO--, --CO-- or --OCOO--; A.sup.1 denotes a single bond, ##STR2## Y.sup.1 and Y.sup.2 independently denote hydrogen, halogen, --CH.sub.3 -- or CF.sub.3 --; and at least one mesomorphic compound represented by the following formula (II): ##STR3## wherein R.sup.3 and R.sup.

Abstract: A mesomorphic compound represented by the following formula (I): ##STR1## wherein R.sub.1 and R.sub.2 respectively denote a linear or branched alkyl group having 1-18 carbon atoms capable of including one or non-neighboring two or more methylene groups which can be replaced with at least one species of --O--, --S--, --CO--, --COO--, --OCO-- and --OCOO--; ##STR2## and n is 0 or 1.

Abstract: A mesomorphic compound represented by the following formula (I): ##STR1## wherein R.sub.1 and R.sub.2 respectively denote an alkyl group having 1-16 carbon atoms capable of having a substituent; X.sub.1 and X.sub.2 respectively denote a single bond, ##STR2## and A.sub.1 and A.sub.2 respectively denote ##STR3## wherein X.sub.3 and X.sub.4 respectively denote hydrogen, fluorine, chlorine, bromine, --CH.sub.3, --CN or --CF.sub.3 ; and Z denotes --O-- or --S--.

Abstract: A ferroelectric chiral smectic liquid crystal composition, comprising at least one compound represented by the following formula (I): ##STR1## wherein R.sub.1 denotes a linear or branched alkyl group having 1-18 carbon atoms capable of having a substituent, R.sub.2 denotes a linear or branched alkyl group having 1-14 carbon atoms capable of having a substituent; X.sub.1 and X.sub.2 respectively denote a single bond, --O--, ##STR2## m is 0-7; and n is 0 or 1; and at least one compound represented by the following formula (II): ##STR3## wherein R.sub.3 and R.sub.4 respectively denote a linear or branched alkyl group having 1-18 carbon atoms capable of having a substituent; X.sub.3 and X.sub.4 respectively denote a single bond, --O--, ##STR4## Y.sub.1 denotes --CH.sub.2 O-- or --OCH.sub.2 --; and p and q are respectively 1 or 2.

Abstract: A liquid crystal composition comprises at least one compound represented by the formula [I] below and at least one compound represented by the formula [II] below: ##STR1## wherein R.sub.1 denotes an alkyl group having 1-16 carbon atoms capable of having a substituent; R.sub.2 denotes any one of alkyl group, alkoxy group, alkoxycarbonyl group, acyloxy group and alkoxycarbonyloxy group, each having 1-16 carbon atoms and being capable of having a substituent; and A denotes any one of ##STR2## each capable of having a substituent; and ##STR3## wherein R.sub.3 denotes a linear alkyl group having 1-16 carbon atoms; R.sub.4 denotes a linear alkyl group having 1-12 carbon atoms; X.sub.1 is a single bond, --O--, ##STR4## X.sub.2 is --OCH.sub.2 --, ##STR5## or --CH.sub.

Abstract: A mesomorphic compound represented by the following formula (I): ##STR1## wherein R.sub.1 and R.sub.2 respectively denote a linear or branched alkyl group having 1-18 carbon atoms capable of having a substituent; X denotes any one of a single bond, --O--, ##STR2## Y denotes ##STR3## or --CH.sub.2 O--; and Z denotes any one of --O--, ##STR4## .

Abstract: A liquid crystal apparatus includes a chiral smectic liquid crystal showing a first and a second orientation state disposed between first and second electrodes of a liquid cell. A drive circuit applies voltages between the first and second electrodes including voltages .vertline.V.sub.S .vertline. and .vertline.V.sub.I .vertline. which provide voltages V.sub.A and V.sub.B (V.sub.B V.sub.A) satisfying the relationship of: .vertline.(V.sub.A -V.sub.B)/(V.sub.A +V.sub.B).vertline.>0.1 at 40.degree. C. V.sub.A is a minimum peak value of a voltage .vertline.V.sub.S .vertline.+.vertline.V.sub.I .vertline. (at a constant pulse width) capable of inverting the first orientation state of the chiral smectic liquid crystal into the second orientation state when a voltage pulse is applied between the first and second electrodes to cause the first orientation state of the chiral smectic liquid crystal and then the voltage .vertline.V.sub.S .vertline.+.vertline.V.sub.I .vertline.

Abstract: A mesomorphic compound represented by the following formula (I): ##STR1## wherein R.sub.1 and R.sub.2 respectively denote an alkyl group having 1-16 carbon atoms capable of having a substituent; X.sub.1, X.sub.2 and X.sub.3 respectively denote a single bond, --O--, ##STR2## A.sub.1 and A.sub.2 respectively ##STR3## wherein X.sub.4 and X.sub.5 respectively denote hydrogen, fluorine, chlorine, bromine, --CH.sub.3, --CN or --CF.sub.3 with proviso that X.sub.1 always denotes a single bond when A.sub.1 denotes a single bond; and n is 0 or 1.

Abstract: A mesomorphic compound represented by the following formula (I): ##STR1## wherein R.sup.1 and R.sup.2 respectively denote a linear or branched alkyl group having 1-18 carbon atoms capable of including one or two or more non-neighboring methylene groups which can be replaced with at least one species of --Z--, ##STR2## --CH.dbd.CH-- and --C.tbd.C--, wherein Z denotes --O-- or --S-- and R.sup.3 denotes hydrogen or an alkyl group having 1-5 carbon atoms; A.sup.1 denotes ##STR3## and A.sup.2 denotes any one of ##STR4## The mesomorphic compound is effective for providing a ferroelectric liquid crystal composition showing an improved low-temperature operation characteristic and a decreased temperature-dependence of response speed.

Abstract: A liquid crystal composition, comprising: at least one compound represented by the following formula (I): ##STR1## wherein R.sub.1 and R.sub.2 respectively denote an optically inactive linear or branched alkyl group having 1-18 carbon atoms capable of including one or non-neighboring two or more methylene groups which can be replaced with at least one species of ##STR2## wherein Z denotes --O-- or --S-- and R.sub.3 denotes hydrogen or an alkyl group having 1-5 carbon atoms; A denotes --A.sub.1 -- or --A.sub.2 --A.sub.3 -- wherein A.sub.1 denotes ##STR3## and A.sub.2 and A.sub.3 respectively denote ##STR4## or --A.sub.1 --; and at least one compound represented by the following formula (II): ##STR5## wherein R.sub.4 denotes a linear or branched alkyl group having 1-18 carbon atoms capable of having a substituent; X.sub.1 denotes a single bond, --O--, ##STR6## X.sub.2 denotes a single bond, --O-- or ##STR7## Z.sub.1 denotes a single bond or ##STR8## A.sub.4 denotes ##STR9## and l is 1-12.

Abstract: An optically active mesomorphic compound represented by the formula: ##STR1## wherein R.sub.1 denotes an alkyl group having 1-16 carbon atoms; R.sub.2 denotes an alkyl group having 1-18 carbon atoms; C* is an asymmetric carbon atom; X is an oxygen atom or sulfur atom; and n is 0 or 1. The optically active mesomorphic compound, when included as a component, provides a ferro-electric liquid crystal composition showing an improved field response characteristic.