Abstract: The invention relates to thermochromic liquid crystalline phases with at least two components, characterized in that at least one component is an optically active compound of the formula I ##STR1## wherein R.sup.1 and R.sup.2 are each independently a chiral residue, importing to the phase a tight helical twist. ##STR2## denotes a 1,4-phenylene group optionally substituted by fluorine, X.sup.1 and X.sup.2 are each independently O or NH,n is 1, 2 or 3 andm is 0 or 1, which can be used in electro-optic devices, in temperature indicating devices or for color-changing cosmetics.

Abstract: A chiral, tilted, smectic liquid crystal phase comprising a mixture of at least two compounds, wherein at least one compound is an achiral fluorinated biphenyldiole compound of formula I ##STR1## whereinR.sup.1 and R.sup.2 are each independently alkoxy or alkanoyloxy with 1 to 15 C atoms, ##STR2## denotes a 4,4-phenylene group optionally substituted by up to four F atoms, and is 1.

Abstract: Novel cyanohydrin derivatives of general formula (I) wherein R.sup.1 is hydrogen, alkyl, alkoxy, perfluoroalkyl or perfluoroalkoxy, R.sup.2 is alkyl, r is 1 to 10, n and m are 0 or 1, provided if both n and m are 0 then X is (II) or (III), where (F) indicates one or more optional fluorines, p is 0 or 1, Z is a single bond if p is 0 and COO if p is 1; and if one or both of n or m are 1 then X is (IV), where each ring A, B and C is phenyl, fluoro- or chloro-phenyl, cyclohexyl, pyrimidyl, pyridyl, or dioxanyl, A, B and C are single bonds or linking groups, and (a+b+c) is 2 or 3. Liquid crystal materials containing these compounds are also described.

Abstract: The invention relates to liquid crystalline compounds of the Formula I ##STR1## wherein R.sup.1, R.sup.2, X.sup.1, X.sup.2, m, and n are as defined herein. Preferably, the group R.sup.2 of the liquid crystalline compounds of Formula I is a chiral residue of the formula II ##STR2## wherein Q denotes an alkylene residue with up to 7 C atoms wherein one CH.sub.2 group may be replaced by --O--, --CO--O--, or --O--CO--, or a single bond; andY denotes an alkyl residue with 2 to 7 C atoms wherein one CH.sub.2 group may be replaced by --O--, --CO--O--, or --O--CO--.The invention further relates to liquid crystal phases containing compounds of the Formula I, to electro-optic and thermographic devices, and to a method of surface thermography.

Abstract: The invenion relates to a display element based on the electroclinic effect containing a liquid crystal medium being a mixture of at least two chiral components and at least one non-chiral component, characterized in that said medium has a pitch compensated cholesteric phase above the optically active smectic A phase.

Abstract: Optically active naphthalene compounds having the formula: ##STR1## in which X and Y are selected from combinations (a), (b) and (c): (a) X is C.sub.1-10 alkyl or alkoxy and Y is C.sub.4-16 optically active alkyl, (b) X is C.sub.1-10 alkyl or alkoxy and Y is ##STR2## where R.sup.2 is C.sub.4-16 optically active alkyl, (c) X is ##STR3## where R.sup.1 is C.sub.1-10 alkyl or alkoxy and Y is C.sub.4-16 optically active alkyl. Ferroelectric smectic liquid crystal materials being compositions containing these compounds are also described.

Abstract: A liquid crystal phase consisting of at least three components A, B and C, each of which contains one or more compounds, wherein component A has a viscosity of at most about 25 mPa.s at 20.degree., a clearing point of at most 130.degree. and a dielectric anisotropy between about -2 and about +2, component B has a dielectric anisotropy above about +8, component C has a clearing point of more than 130.degree. and a dielectric anisotropy between about -2 and about +2, characterized in that component A contains at least one compound of the formula III ##STR1## in which R.sup.1 is alkyl of 1 to 12 C atoms, in which in addition one or two non-adjacent CH.sub.2 groups can be replaced by O atoms, --CO--, --O--CO--, --CO--O-- and/or --CH.dbd.CH-- groups,R.sup.2 has one of the meanings of R.sup.1, ##STR2## Z.sup.1 is --CO--O--, --O--CO-- or --CH.sub.2 CH.sub.2 --, o is 1 or, if A.sup.

Abstract: Biphenyl egters of formula (I), ##STR1## wherein formula (II) represents formula (III) or formula (IV), R.sub.1 represents C.sub.3 -C.sub.12 alkyl, alkoxy, alkylcarbonyloxy, alkoxycarbonyl or alkoxycarbonyloxy, j is O or 1 R.sub.2 represents C.sub.3 -C.sub.12 alkyl or alkoxy, one of Q.sub.1 or Q.sub.2 is fluorine and the other is hydrogen, provided that when j is O and formula (II) is formula (III) and both R.sub.1 and R.sub.2 are n-alkyl, then the total number of carbon atoms in R.sub.1 and R.sub.2 is more than 12. These compounds may be used as constituents of liquid crystal mixtures which show a room temperature ferroelectric smectic phase, and a number of such mixtures are described.

Abstract: The invention relates to ferroelectric smectic liquid crystal mixtures and compounds. The invention also relates to electro-optical devices incorporating these mixtures.

Abstract: Liquid crystal phases containing components of the formulae I and III ##STR1## have an acceptable combination of threshold steepness, viewing angle and temperature dependence at a low threshold voltage.

Abstract: Liquid crystal compositions comprising as a first part between 40 and 99% by weight in aggregate of one or more materials selected from one or more of the six compound classes (1) to (3'), wherein R is in every instance an alkyl chain containing between 2 and 18 carbon atoms and R' is in every instance an alkyl chain containing between 1 and 17 carbon atoms, wherein one or more non-adjacent CH.sub.2 -groups are replaced by oxygen atoms, and as a second part between 1 and 60% by weight of one or more materials of high birefringence and high positive dielectric anisotropy which raise the S.sub.A -N transition temperature, exhibit a smectic A phase of relatively low melting point and wide smectic range. Such compositions may be used in liquid crystal cells, not only in display or optical information processing applications, but also for instance in temperature sensing applications. The operation of such cells may involve laser addressing, thermal or electrical addressing.

Abstract: Biphenyl esters of formula (I), wherein formula (II) represents formula (III) or formula (IV), R.sub.1 represents C.sub.3 -C.sub.12 alkyl, alkoxy, alkylcarbonyloxy, alkoxycarbonyl or alkoxycarbonyloxy, j is 0 or 1, R.sub.2 represents C.sub.3 -C.sub.12 alkyl or alkoxy, one of Q.sub.1 or Q.sub.2 is fluorine and the other is hydrogen, provided that when j is 0 and formula (II) is formula (III) and both R.sub.1 and R.sub.2 are n-alkyl, then the total number of carbon atoms in R.sub.1 and R.sub.2 is more than 12. These compounds may be used as constituents of liquid crystal mixtures which show a room temperature ferroelectric smectic phase, and a number of such mixtures are described.

Abstract: Novel compounds for use in ferroelectric smectic liquid crystal mixtures are provided, having a general formula: ##STR1## where R.sub.1 is alkyl, alkoxy, alkylcarbonyloxy or alkoxy-carbonyl, ##STR2## are cyclic groups, A and B are a single bond, COO, OOc, CH.sub.2 CH.sub.2, CH.sub.2 O or OCH.sub.2, (a+b+c) is 2 or 3 and R.sub.2 is an optically active alkyl group. Ferroelectric smectic liquid crystal mixtures containing these compounds, and a suitable ferroelectric liquid crystal device are also described.

Abstract: Liquid crystal compositions containing at least one compound of the formula IR-Dio-Ph-CN Iwherein R is alkyl of 2 to 5 carbon atoms, Dio is trans-1,3-dioxane-2,5-diyl and Ph is 1,4-phenylene, and at least one compound of each of the following groups A to D:R.sup.1 -Cy-Ph-R.sup.2 AR.sup.3 -Cy-Ph-Ph-R.sup.4 BR.sup.5 -Cy-Ph-CN CR.sup.6 -Cy-COO-Ph-O-R.sup.7 Dand, in addition in a total amount of 10 to 26% by weight at least five compounds of the formula ER.sup.8 -Pyr-Ph-O-R.sup.9 Eor at least one compound of each of the following groups F to K:R.sup.10 -Ph-COO-Ph-R.sup.11 FR.sup.12 -Cy-COO-Ph-Ph-CN GR.sup.13 -Ph-Ph-COO-Ph-Ph-CN HR.sup.14 -Ph-COO-Ph-COO-Ph-R.sup.15 JR.sup.16 -Ph-Ph-COO-PhF-R.sup.17 Kresult in surprisingly steep electrooptical characteristics and surprisingly low viewing-angle dependence of the contrast at simultaneously acceptable threshold voltages for commercially available drivers and multiplex ratios up to 1:100 when used in matrix displays.

Abstract: A fluorinated compound having a formula: ##STR1## R.sub.1 is hydrogen or alkyl having up to 12 carbon atoms; R.sub.2 is selected from hydrogen, alkyl having up to 12 carbon atoms, alkoxy having up to 12 carbon atoms, ##STR2## wherein R.sub.3 is hydrogen or alkyl having up to 12 carbon atoms, and wherein R.sub.4 is hydrogen, alkyl having up to 12 carbon atoms or alkoxy having up to 12 carbon atoms; ##STR3## represents a cyclohexane ring which is in the trans configuration if 1, 4-disubstituted; ##STR4## represents a benzene ring; each of X, Y and Z independently represents hydrogen or fluorine in one or more of the lateral benzene ring positions, provided that at least one of X, Y and Z is present representing fluorine;n=0 or 1 provided that when n=0 ##STR5## and R.sub.1 is alkyl; with the proviso that in Formula I when n is 1 and ##STR6## where R.sub.1 is n-alkyl and R.sub.2 is n-alkyl or n-alkoxy the total number of carbon plus oxygen atoms in the two groups R.sub.1 and R.sub.2 is less than 10.

Abstract: Disubstituted ethanes having a formula ##STR1## wherein R is alkyl, X is selected from hydrogen, ##STR2## wherein each R.sub.1 is selected from H, alkyl, alkoxy, halo and cyano and each of Q.sub.1, Q.sub.2, Q.sub.3 and Q.sub.4 is independently selected from H and F are useful as components of liquid crystal materials for electro-optical displays and compounds useful in the production of such components.