Abstract:
The instant invention relates to liquid crystal media comprising a strongly dielectrically positive component A, preferably comprising isothiocyanate compounds, most preferably compounds of formula I, as given in the text, and a further dielectrically positive component B, preferably comprising terminally polar substituted bi- or terphenyl compounds, most preferably comprising compounds of formula II, as given in the text, further to novel isothiocyanato compounds as well as to liquid crystal displays comprising these media, in particular to PDLC display and most particular to holographic PDLC displays. The instant invention further relates to compounds of formula I wherein the parameters are as as specified in the text.
Abstract:
Described are catalyst systems having aluminium alkyl complexes of the formula (I) described herein applied to magnesium chloride, SiO2 or SiO2 in combination with MgCl2 as support in the presence of titanium halides or vanadium halides and internal and, if desired, external donors act both as cocatalysts and as stereoselectivity promoters in heterogeneous polymerizations of &agr;-olefins. Also described are polymerization methods using these catalyst systems.
Abstract:
1,4-disubstituted 2,6-difluorobenzene compound of formula I wherein R is an alkyl or alkenyl radical, A1 and A2 are independently (a) a trans-1,4-cyclohexylene radical in which a CH2 group may be replaced by -O- and/or -S, (b) a 1,4-phenylene radical in which a CH group may be replaced by N, (c) 1,4-cyclohexenylene, 1,4-bicyclo(2,2,2)octylene, piperidine-1,4-diyl, naphthalene-2,6-diyl, decahydronaphthalene-2,6-diyl or 1,2,3,4-tetrahydronaphthalene-2,6-diyl, Z1 and Z2 are —CO—O—, —O—CO—, —CH2O—,—OCH2—, —CH2CH2—, —CH═CH—,—C≡C—or a single bond m and n are 0, 1, 2 or 3, (m+n) is 1, 2 or 3, X is R or F, Cl, CF3, —OCF3, or —OCHF2, —OCF5, —CN or —NCS with the provisos that at least one of the radicals A1 and A2 present in the molecule is and at least one of Z1 or Z2 is —COO—, are suitable as components of liquid-crystalline media.
Abstract:
The invention relates to a liquid-crystal display based on a twisted nematic cell and having two substrates provided with electrode layers and alignment layers thereon and, with a frame, forming a cell, a nematic liquid-crystal mixture having positive dielectric anisotropy present in the cell, and a twist angle of the liquid-crystal layer in the cell with a value of between 0.degree. and 600.degree. from alignment layer to alignment layer,whose liquid-crystal mixture is based on medium-polarity compounds of the SFM type which are selected so that the liquid-crystal mixture has a viscosity at 20.degree. C. of less than 30 mm.sup.2 s.sup.-1 and has a value of K/.DELTA..di-elect cons..ltoreq.1.5 for the quotient of the Frank constant K ##EQU1## and the dielectric anisotropy .DELTA..di-elect cons. .DELTA..di-elect cons.=.di-elect cons..vertline.-.di-elect cons..sub..perp.when used in a TN cell (.nu.=.pi./2, d/p
Abstract translation:本发明涉及一种基于扭转向列单元的液晶显示器,具有在其上设置有电极层和取向层的两个基板,并且具有形成单元的框架,存在于该介质各向异性中的正的介电各向异性的向列型液晶混合物 电池中的液晶层和从配向层到取向层的值在0〜600度之间的电池中的液晶层的扭转角,其液晶混合物基于SFM型的中极性化合物 选择为使得液晶混合物在20℃下的粘度小于30mm 2 s -1,并且具有值+ E,ovs K + EE / DELTA +531 <= 1.5,对于Frank的商 常数+ E,ovs K + EE 和介电常数各向异性DELTA +531 DELTA +531 = + 531 | - + 531当在TN单元中使用ORTHOGONAL(nu = pi / 2,d / p << 1)+ E,ovs K + EE / DELTA +531 = 1.5其中nu是以rad为单位的扭转角,d为层厚度,单位为μm,p为间距,m1为K11,K22为 d K33是10-12N中弹性,扭转和弯曲的弹性常数。
Abstract:
Fluorobenzene derivatives of formula I, ##STR1## in which R an alkenyl radical as further defined in the specification,A.sup.1 and A.sup.2 are a trans-1,4-cyclohexylene radical, 1,4-phenylene radical or other cyclic structure as further defined in the specification,Z.sup.1 and Z.sup.2 are a single bond or bridging group,L is H or F,m is 0, 1 or 2,Y is F or Cl, andQ is a single bond.
Abstract:
A nematic liquid crystalline medium having at least two liquid crystalline components with at least one being of formula I ##STR1## wherein R is H, a straight-chain alkyl or alkenyl radical having 1 to 15 carbon atoms, it also being possible to replace one or more CH.sub.2 groups in these radicals, independently of one another, by --O--, --S--, ##STR2## --CO--, --CO--O--, --O--CO-- or --O--CO--O-- in such a way that oxygen atoms are not linked directly to one another,Z.sub.1 and Z are each, independently of one another, --CH.sub.2 --CH.sub.2 --, --CH.dbd.CH--, --C.tbd.C-- or a single bond, and one of the radicals Z.sup.1 and Z is alternatively --(CH.sub.2).sub.4 -- or --CH.dbd.CH--CH.sub.2 CH.sub.2 --,A and A.sup.1 are each, independently of one another, trans-1,4-cyclohexylene in which, in addition, one or two non-adjacent CH.sub.2 groups may be replaced by --O--, or are 1,4-phenylene which is unsubstituted or monosubstituted or disubstituted by fluorine and/or Cl atoms and in which, in addition, one or two CH groups may be replaced by N,m is 0, 1, 2 or 3,o and s are 0, 1 or 2, where (s+o) is >2.These liquid crystalline media find use in electro-optical display elements.
Abstract:
The invention relates to liquid crystal compounds having a terminal structure in accordance with formula 1, 2, 3 or 4:--A.sup.3 --OCF.sub.3 1--A.sup.2 --Q--CHF.sub.2 2--3,5-difluoro-1,4-phenylene-X.sup.1 3--3-fluoro-1,4-phenylene-X.sup.2 4wherein A.sup.2, A.sup.3, X.sup.1 and X.sup.2 and are defined herein. The invention further relates liquid crystal phases containing the above components as well as electrooptical displays containing same.
Abstract:
The invention relates to a matrix liquid-crystal display (MLCD) containing a liquid-crystal mixture based on dielectrically positive liquid-crystal compounds which have a polar end group with a lipophilicity parameter, .pi., value of .gtoreq.0.1.
Abstract:
Benzene derivatives of the formula I ##STR1## in which n is 1 to 7, Q is --CO or --(CH.sub.2).sub.r --, where r is 1 to 5, s is 0, 1 or 2, t is 0 or 1, where s+t.gtoreq.1, X is F, Cl, --CF.sub.3, --CN, --OCF.sub.3 or --OCHF.sub.2, and Y, L and Z are each, independently of one another, H or F.
Abstract:
Optically active nitrogen-containing heterocycles of the formula I according to claim 1 are suitable as components for ferroelectric liquid crystalline materials.