Abstract: A ferroelectic smectic C liquid crystal mixture and a display element having a quick electrooptical response and a good memory property are provided, the ferroelectric mixture having a Ps of 60 nC/cm2 or more and a tilt angle of 24.degree. or more and comprising(A) a first component comprising at least one optically active compound expressed by the formula ##STR1## wherein l and m are 0 or 1, both are not 1; n is an integer of 3 to 8; X and Y are H, F, Cl, or CN, both X and Y are not H; A is --COO-- or --OCO--; and R is C3--8 alkyl or alkoxy , and(B) a second component comprising at least one optically active compound expressed by the formula ##STR2## wherein l, m, n and R are as defined above; and A is --COO--, --OCO--, --CH.sub.2 O-- or --OCH.sub.2 --, a total content of the first and second components being 60 mol % or more in the mixture.

Abstract: The present invention is directed to a ferroelectric liquid crystal composition having quick response properties and assuming a smectic C* phase in an extensive temperature range inclusive of room temperature, and an optical switching element having a quick response property containing this composition.The ferroelectric liquid crystal composition is here disclosed which comprises at least one chiral compound (liquid crystal component A) having an optical activity site represented by the formula (A) ##STR1## wherein R.sup.1 is a straight-chain or branched alkyl group having 2 to 18 carbon atoms or a straight-chain or branched alkoxy group having 1 to 18 carbon atoms, and * indicates an asymmetric carbon atom,and at least one non-chiral compound (liquid crystal component B) having a smectic C phase (hereinafter referred to as "S.sub.C phase"; which shall apply in the following), an S.sub.I phase, an S.sub.F phase, an S.sub.G phase, an S.sub.H phase, an S.sub.J phase or an S.sub.K phase.

Abstract: A nematic liquid crystal composition having a notable increase of the twistability (i.e. the reciprocal of the intrinsic helical pitch) with temperature rise is provided, which composition comprises (i) optically active substance(s) which are the same in the helical twist sense to one another and make positive the temperature dependency of the twistability of the cholesteric phase induced when singly added to nematic compound(s), and (ii) nematic liquid crystal(s), which optically active substance(s) are a specificed compound (I) containing a plurality of benzene, cyclohexane, dioxane, pyrimidine or/and pyridine ring and also having an optically active terminal group ##STR1## (R.sup.

Abstract: A ferroelectric liquid crystal composition having a negative large dielectric anisotropy value, AC stabilizing effect at low voltages and yet high-speed response properties, and a light switching element using the composition are provided, which composition comprises at least two components at least one of which is a compound expressed by the formula ##STR1## wherein R.sup.3 and R.sup.4 each represent the same or different linear or branched alkyl group of 1-18C and l is 1 or 2, and having a negative dielectric anisotropy value.A preferred embodiment of the above composition contains at least three components A, B and C, one of which is the above compound of the formula (A) and components B and C of which are each selected from a group of specified compounds, and the respective proportions of components A, B and C being 5-50 weight %, 20-70 weight % and 5-40 weight % based on the total weight of the three, respectively.

Abstract: The present invention relates to a liquid crystal composition used for thermal writing type liquid crystal display devices utilizing a thermooptical effect, and a liquid crystal display element using the composition.The object of the present invention is to provide a liquid crystal composition having an extremely narrow nematic range and a low-melting phase transition point, and also to provide a liquid crystal display element using the composition.The present invention is directed to a liquid crystal composition mainly comprising a component A comprising 4-n-octyl-4'-cyanobiphenyl, 4-n-dodecyl-4'-cyanobiphenyl and at least one member of 4-n-alkyl-4'-cyanobiphenyls represented by the formula (I), ##STR1## wherein R.sup.1 is an alkyl group of 9, 10 or 11 carbon atoms, and a component B comprising at least one member of 4-n-alkanolyloxy-4'-cyanobiphenyls represented by the formula (II) ##STR2## wherein R.sup.

Abstract: The present invention relates to a liquid crystal composition for use in thermal writing type liquid crystal displays in which a thermooptical effect is utilized. A technical subject of the present invention is to provide a liquid crystal composition characteristically having an extremely narrow nematic range and a low-melting phase transition point, and another object of the present case is to provide a liquid crystal display element using this composition.The present invention is directed to a liquid crystal composition which comprises a component A comprising at least one of 4-n-alkyl-4'-cyanobiphenyls represented by the formula (1) ##STR1## wherein R.sup.1 is an alkyl group having 8, 9, 10, 11 or 12 carbon atoms, and a component B comprising at least one of 4-n-alkoxycarbonyloxy-4'-cyanobiphenyls represented by the formula (2) ##STR2## wherein R.sup.2 is an alkyl group having 8, 9, 10, 11 or 12 carbon atoms, a ratio of the component A to the component B being from 25:75 to 95:5.

Abstract: The present invention provides diamino compounds and liquid crystal aligning films comprising polyimides which are obtained from the said diamino compounds represented by the general formula: ##STR1## wherein R.sub.1 indicates an alkyl group having 3 to 22 carbon atoms, R.sub.2 indicates a hydrogen atom or an alkyl group having 1 to 22 carbon atoms, and R.sub.3 -R.sub.10 indicate a hydrogen atom or a methyl group, respectively.The liquid crystal aligning films are useful for STN mode display cells in realizing a high pretilt angle.

Abstract: A ferroelectric chiral smectic liquid crystal composition containing two kinds of chiral smectic liquid crystal compound is provided. One of the said compounds shows twist sense of helix of right-handed and the other show twist sense of helix of left-handed and the direction of spontaneous polarization of component chiral smectic liquid crystal compounds is the same. This composition provides a liquid crystal display element which shows very quick response.

Abstract: A ferroelectric liquid crystal composition is here provided which contains at least one chiral compound having an optical activity site group represented by the general formula (I) ##STR1## wherein R.sup.1 is a straight-chain or branched alkyl group or alkoxy group having 1 to 18 carbon atoms, and * indicates an asymmetric carbon atom, and at least one non-chiral compound having a smectic C phase, a smectic I phase, a smectic F phase, a smectic G phase, a smectic H phase, a smectic J phase or a smectic K phase. This composition has quick response properties and assumes an SC* phase in an extensive temperature range inclusive of room temperature. Furthermore, by using this composition, an optical switching element having quick responsiveness can be obtained.

Abstract: A ferroelectric liquid crystal composition having a negative dielectric anisotropy, a good AC-stabilizing effect and still high-speed response properties, and a light switching element, are provided, which composition comprises a compound expressed by the formula ##STR1## wherein R.sup.1 and R.sup.2 each represent a linear or branched alkyl group, alkoxy group, alkanoyloxy group, alkoxycarbonyl group, alkoxycarbonyloxy group or alkanoyl group each of 1 to 18 carbon atoms; ##STR2## X.sub.1, X.sub.2 and X.sub.3 each represent hydrogen atom or halogen atom; P and Q each represent 0 or 1; and P+Q is 0 or 1.

Abstract: The present invention relates to a ferroelectric liquid crystal composition having quick response and comprising a smectic liquid crystal compound and an optically active compound.The ferroelectric liquid crystal composition comprises components A and B, said component A comprising a compound represented by the formula: ##STR1## and/or a compound represented by the formula: ##STR2## said component B comprising a compound represented by the formula: ##STR3## and/or a compound represented by the formula: ##STR4## wherein R.sup.1, R.sup.2, R.sup.3 and R.sup.5 are each an alkyl or alkoxy group of 1 to 18 carbon, R.sup.4 and R.sup.6 are each an alkyl group of 2 to 18 carbon atoms or an alkoxy group of 1 to 18 carbon atoms, X and Y are each --CH.sub.2 O--, --OCH.sub.2 --, ##STR5## m, n, k and l are each an integer of 1 or 2 and * is an asymmetric carbon atom, the component A to component B ratio being 1.5 or less.

Abstract: Diamino compounds, dinitro compounds, diol compounds and a process for preparing the diamino compounds which are useful as materials of poly-imide compounds for obtaining aligning films having high pretilt angles in liquid crystal display elements are provided.The diamino compounds are represented by the general formula: ##STR1## wherein R.sub.1 -R.sub.6 are a hydrogen atom or an alkyl group having 1 to 22 carbon atoms, respectively, and R.sub.7 -R.sub.12 are a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, F or Cl respectively.

Abstract: A ferroelectric smectic C liquid crystal mixture having a smectic A phase region within 30.degree. C. on the higher temperature side relative to a chiral smectic C phase and also having a tilt angle at its chiral smectic C phase in the range of 30.degree. to 60.degree..

Abstract: A ferroelectric chiral smectic liquid crystal composition affording a high response speed and being cheap so that a high speed switching can be effected, which composition comprises at least one achiral smectic C compound and at least one chiral smectic C compound, characterized in that at least one of said at least one achiral smectic C compound contains at least two divalent six-memberd ring, directly linked by at least one single bond, at least one of said at least two divalent six-membered rings being selected from pyrimidin-2,5-diyl, pyridin-2,5-diyl, 1,4-phenylene or trans-1,4-cyclohexylene.

Abstract: A ferroelectric liquid crystal material having a long helical pitch and still having a large spontaneous electric polarization and superior response property can be provided by mixing a chiral smectic compound or compounds having a twist sense of helix right-handed with other chiral smectic compound or compounds having a twist sense of helix left-handed and also a light switching element is provided in which the above-mentioned ferroelectric chiral smectic liquid crystal composition is used.

Abstract: A ferroelectric liquid crystal composition having a long helical pitch and a light switching element having a quick response property are provided. This composition comprises (1) at least one member selected from the group consisting of liquid crystal compounds having a smectic C phase and no helical structure and liquid crystal compounds having only a nematic phase as a liquid crystal phase and no helical structure and (2) at least one chiral smectic liquid crystal compound.

Abstract: A nematic liquid crystal composition for multiplex drive display elements having superior characteristics, particularly a steep voltage-transmittance characteristic, is provided which composition comprises:(1) 10 to 50% by weight of first component comprising compound(s) of the formula ##STR1## wherein R.sub.1 1-8C alkyl and (2) 20 to 90% by weight of a second component comprising compounds of the following formulas (II), (III), (IV), (V) and (VI), the respective contents of which are 0-40, 0-50, 0-40, 0-40 and 0-40% by weight, the total weight of the first and second components being 60% by weight or more: ##STR2## wherein R.sub.2 is 1-10C alkyl, R.sub.

Abstract: A liquid crystal display comprising two substrates and a nematic liquid crystal present between said two substrates, wherein each of said substrates comprises a glass plate, an electrode thereon and an aligning layer subjected to a molecular aligning treatment for a pretilt angle of 1.degree. to 30.degree. on the electrode, wherein an optically active material is added to the nematic crystal which has a positive dielectric anisotropy, wherein the average alignment direction in the longer direction of said liquid crystal molecule is twisted at an angle .phi. of 210.degree. to 300.degree. to impart a spiral structure to the liquid crystal and a ratio d/p of the spiral pitch p of the liquid crystal molecule and the liquid crystal thickness d are(.phi./360-1/4)<d/p<.phi./360;an improvement being present in that the nematic liquid crystal contains one or more compounds represented by the following formula (I) in an amount of not less than 10% by weight: ##STR1## wherein n.sub.1 and n.sub.

Abstract: A ferroelectric liquid crystal composition exhibiting SC* phase within a broad temperature range including room temperature and also having high-speed response properties and a light switching element using the above-mentioned liquid crystal composition and exhibiting high-speed response properties are provided, which composition comprises at least one member of chiral compounds expressed by the formula ##STR1## wherein R.sup.1 and R.sup.2 each represent a linear or branched chain alkyl, alkoxy, alkoxyalkoxy, alkoxycarbonyl, alkanoyl or alkanoyloxy group each of 1 to 18 C and at least one of R.sup.1 and R.sup.2 has an asymmetric carbon atom in the alkyl chain moiety of these groups, and at least one member of chiral compounds having a spontaneous polarization value of 40 nC/cm.sup.2 or more.

Abstract: A ferroelectric liquid crystal composition exhibiting SC* phase within a broad temperature range including room temperature and yet having cholesteric phase and further high-speed response properties and a light switching element using the above composition and having high-speed response properties are provided, which composition comprises an achiral compound expressed by the formula ##STR1## wherein R.sup.1 and R.sup.2 each represent the same or different linear or branched chain alkyl group of 1 to 18 carbon atoms, in 20 to 70% by weight and having cholesteric phase; and which composition may further comprise at least one member of optically active compounds selected from four specified pyrimidine compounds.