摘要:
A ferroelectric liquid crystal switching or display device, in which the liquid crystal film has a constant thickness, wherein one of the glass sheets in the device is planar and the other glass sheet has at least one step. The switching or display device of the present invention does not require shortened switching times or more contacts or drivers and does not show unwanted switching.
摘要:
Optically active 1,3-dioxolane derivatives which carry a mesogenic radical in the 4-position and have the general formula (I) ##STR1## are suitable for use as doping agents in liquid-crystal mixtures--in particular ferroelectric liquid-crystal mixtures. The symbols in the general formula have the following meanings:R.sup.1 is composed analogously to the part of the general formula on the right-hand side of X or is an alkyl or alkylene radical which can be substituted,R.sup.2, R.sub.3 and R.sup.4 are H or alkyl (R.sup.4 is also alkenyl) which can also be substituted [R.sup.2 and R.sup.3, together with the C(2) of the dioxolane ring are also a cycloaliphatic radical or a keto group], J, l and n are zero, 1 or 2 and k and m are zero or 1, subject to the proviso that, if k is zero n is zero and if n is zero m is zero and 1.ltoreq.J+l+n.ltoreq.3,--A.sup.1, --A.sup.2 and --A.sup.3 are an aromatic, heterocyclic or aliphatic ring system, --M.sup.1 and --M.sup.2 are --CO--O, --0--CO, --CH.sub.2 CH.sub.2, --CH.dbd.CH, --CH.sub.2 O, --OCH.sub.2 or --C.tbd.C andX is O, S or O--CO--O.
摘要:
Optically active, mesogenic 1,3-dioxolane-4-carboxylates are suitable as dopes in liquid-crystal mixtures. They result in liquid-crystalline ferroelectric phases having short switching times and in electroclinic phases having large electroclinic coefficients. Their particular advantage is that they induce a helix of very large pitch, meaning that helix compensation by further dopes is unnecessary. In addition, the 1,3-dioxolane-4-carboxylates exhibit high UV stability.
摘要:
The novel liquid-crystalline mixtures (in the case of ferroelectric behavior they additionally contain an optically active compound as dope) are constructed from at least 2 mixture components of the general formula (I): ##STR1## wherein n=6 to 14 and x=2 to 14. In addition, the mixtures may also contain cyclohexanecarboxylates of the general formula (II) ##STR2## where R.sup.1 =(C.sub.10 -C.sub.16) or (C.sub.8 -C.sub.14)alkoxy and R.sup.2 =(C.sub.2 -C.sub.9)alkyl, alkenyloxyphenylpyrimidine derivatives of the general formula (III) ##STR3## where R.sup.3 =(C.sub.7 -C.sub.16)alkyl or (C.sub.6 -C.sub.14)alkoxy and y=4-14, and/or alkoxyphenyl derivatives of alkylpyrimidine, of the general formula (IV) ##STR4## where m and p=6 to 14.
摘要:
Liquid-crystal 5-phenylpyrmidine derivatives having S.sub.c or S.sup.*.sub.c phases and a process for preparing them. The new liquid-crystal 5-phenylpyrimidine derivatives have an S.sub.c or S.sup.*.sub.c phase and are described by the general formula (I) ##STR1## in which the symbols have the following meaning: R.sup.1 and R.sup.2 denote identical or different, straight-chain or branched alkyl or alkenyl groups having from k to 16 carbon atoms, with or without an asymmetric carbon atom, in which one or more non-adjacent --CH.sub.2 -- groups can be replaced by --O-- and /or --S----A and --B each denote ##STR2## in which the radicals R.sup.1, R.sup.2, in each case, are situated at the phenylene part of --A, --B and m and n denote 0 or 1, but m and n do not simultaneously denote 1, with the following provisos:(a) if m=n=0, k is 8, and in R.sup.2 the --CH.sub.2 -- group adjacent to the phenyl nucleus is replaced by --O--;(b) if m=1 and n=0, k is 2, and(c) if m=0 and n=1, k is 2 and in R.sup.2 the --CH.sub.2 -- group adjacent to the phenyl nucleus is replaced by --O--.
摘要:
Liquid-crystalline phenylpyrimidinyl cyclohexanecarboxylates having a smectic phase, a process for their preparation, and their use in liquid-crystal mixtures The phenylpyrimidinyl trans-cyclohexanecarboxylates of the general formula ##STR1## form a smectic C phase besides a relatively broad nematic phase when R.sup.1 denotes an alkyl radical having 10 to 16 carbon atoms, in particular 11 to 16 carbon atoms, or an alkoxy radical having 8 to 14 carbon atoms, and R.sup.2 denotes an alkyl radical having 2 to 9 carbon atoms. They are therefore particularly suitable as components of liquid-crystalline mixtures having a smectic C phase since they induce a relatively broad nematic phase or extend a narrow nematic phase which is present and extend the temperature range of the smectic C phase to low temperatures, but in particular to high temperatures.
摘要:
The compounds of the general formula (I) ##STR1## are particularly highly suitable as components of smectic, liquid-crystal mixtures, the symbols having the following meaning: R.sup.1 and R.sup.2 denote identical or different, straight-chain or branched alkyl or alkenyl groups which can contain asymmetric carbon atoms, containing 2 to 16 carbon atoms, in which one or more non-adjacent --CH.sub.2 -- groups can be replaced by --O-- and/or --S--, --A and --B each denote group ##STR2## in which the radicals R.sup.1, R.sup.2, in each case, are situated at the phenylene part of --A, --B and m and n denote 0 or 1, but m+n is always zero or 1.
摘要:
Optically active oxirane-2-carboxylic acid esters with a mesogenic molecular component suitable as dopants in liquid-crystal mixtures. They result in liquid-crystalline ferroelectric phases with short switching times and in electroclinic phases with large electroclinic coefficients. A further advantage lies in the fact that they induce a helix with a very small pitch so that they are also suitable for helix compensation in LC mixtures.
摘要:
Use of compounds or mixtures of compounds which have a chiral, orthogonal, more highly ordered smectic phase in the range of said phase as switching or indicating medium.Compounds which have a chiral, orthogonal, more highly ordered smectic phase, in particular an S.sub.B * or an S.sub.E * phase, can be used in the range of said phase or phases as indicating or switching medium in electro-optical indicating or switching components (devices) which are based on the exploitation of the electroclinic effect.
摘要:
The novel compounds are aryl-2,3-epoxyalkyl ethers or thioethers or the corresponding thiirane compounds having a mesogenic aromatic component and a chiral component having a three-membered heterocyclic ring, wherein, in the general formula (1), ##STR1## the symbols have the following meaning: R.sup.1 =straight-chain or branched (C.sub.1 -C.sub.12) alkyl, where one or two non-neighboring CH.sub.2 groups may be replaced by O or S atoms.A=diazine-2,5-diyl or diazine-3,6-diyl,X and Y=O and/or S, andR.sup.2, R.sup.3 and R.sup.4, independently of one another=H, straight-chain (C.sub.1 -C.sub.10) alkyl or branched (C.sub.3 -C.sub.10) alkyl, where R.sup.2, R.sup.3 and R.sup.4 are not simultaneously H.The compounds are preferably employed in tilted smectic liquid-crystal phases which they convert into ferroelectric liquid-crystal phases; they have high values for spontaneous polarization or they induce high values for spontaneous polarization.