摘要:
The invention relates to compounds of the formula (I) having a fluorinated anthracene or fluorinated tetrahydroanthracene core structure and to liquid-crystal mixtures comprising these compounds and to the use thereof in liquid-crystal displays.
摘要:
Tetrahydrothiophene derivatives of the formula (I) R1—X—(A1—M1)a—(A2—M2)b—A3—Y—T—Z—R2 (I) where the symbols and indices have the following meanings, for example: T is undirected and is tetrahydrothiophene-2,5-diyl or tetrahydrothiophene-2,4-diyl R1 is hydrogen or a straight-chain or branched C1-20-alkyl or C2-20-alkenyl radical (with or without asymmetric carbon atoms), R2 is hydrogen or a straight-chain or branched alkyl radical (with or without asymmetric carbon atoms) having 1 to 20 carbon atoms, X is a single bond, —O—, OC(═O)—, —C(═O)O— or —OC(═O)O— Y is —OC(═O)—, —SC(═O)—, —OCH2— or —CH2CH2— Z is a single bond or —O— A1, A2 and A3 are undirected different and are each, independently of one another phenylene-1,4-diyl, M1 and M2 are undirected and are each, independently of one another —OC(═O)—, —OCH2—, —CH2CH2—, —OC(═O)CH2CH2—, —OCH2CH2CH2—, —C≡C—, —CH2CH2CH2CH2— or a single bond; a and b are each, independently of one another, 0 or 1, can be used in liquid-crystal mixtures.
摘要:
A smectic liquid crystal mixture comprising a smectic liquid crystal base mixture and at least one dopant, which is either a complex ligand or an organic material, in a concentration of 0.01 to 5.0 weight percent.
摘要:
The monostable ferroelectric active matrix display contains a liquid crystal layer in from of a monodomain with an unambiguously defined direction of the normal z to the layer of the smC* phase and is characterized by the fact that the normal z to the layer and the preferential direction n of the nematic or cholesteric phase (N* phase) form an angle of more than 5°.
摘要:
The active-matrix display contains a chiral smectic liquid-crystal mixture comprising at least one compound of the formula (I) R1—(A1—M1)a—(A2—M2)b—A3—X—B1—(B2)c—R2 (I). where the symbols are as defined in the description.
摘要:
An active matrix display comprises a chiral smectic liquid crystal mixture which has the phase sequence I—N*—SmC*, a spontaneous polarization in the operating temperature range of 10 &mgr;m at at least one temperature in the nematic or cholesteric phase and comprises at least one compound each from at least two of the substance classes (A), (B) and (C) and one or more compounds from substance class (D): (A): compounds comprising two rings which are directly linked to one another and are selected from phenylene-1,4-diyl, pyrimidine-2,5-diyl, pyridine-2,5-diyl and pyridazine-2,5-diyl with the proviso that at least one of these rings is a nitrogen heterocycle; (B): compounds comprising three rings selected from phenylene-1,4-diyl, two of the rings being directly linked to one another and the third ring being linked to one of the other two rings via an —OC(═O)— or —C(═O)—group, with the proviso that at least one of the three rings is fluorophenylene-1,4-diyl or ortho-difluorophenylene-1,4-diyl; (C): compounds comprising three rings which are directly linked to one another and are selected from phenylene-1,4-diyl, pyrimidine-2,5-diyl, pyridine-2,5-diyl and pyridazine-2,5-diyl with the proviso that at least one of these rings is a nitrogen heterocycle; (D): compounds comprising mesogenic groups suitable as components of liquid crystal mixtures.
摘要:
The monostable ferroelectric active matrix display comprises a liquid-crystal layer in the form of a monodomain having an unambiguously defined direction of the layer normal z of the smC* phase, the liquid-crystal layer preferably having a chevron C-1, chevron C-2 or bookshelf geometry.
摘要:
Phenanthridine derivatives, and their use in liquid-crystalline mixtures A ferroelectric liquid-crystal mixture containing one or more phenanthridine derivatives of the formula (I) ##STR1## E.sup.1 and E.sup.2 are identical or different and are --N--, --CF-- or --CH--; R.sup.1 and R.sup.2 are identical or different and are, for example, a straight-chain or branched alkyl radical having 1 to 20 carbon atoms; Q is --CH.sub.2 --O--, --CO--O-- or a single bond; M.sup.1 and M.sup.2 are identical or different and are --CO--O--, --O--CO--, --CH.sub.2 --O--, --O--CH.sub.2 --, --CH.sub.2 --CH.sub.2 --, --C.tbd.C--, or a single bond; A.sup.1 and A.sup.2 are identical or different and are 1,4-phenylene, in which one or more H atoms may be replaced by F, trans-1,4-cyclohexylene, pyrimidine-2,5-diyl, pyridine-2,5-diyl, where one H atom may be replaced by F, 1,3,4-thiadiazole-2,5-diyl, 1,3-dioxane-2,5-diyl, 1,3-dithiane-2,5-diyl, 1,3-thiazole-2,4-diyl, 1,3-thiazole-2,5-diyl, thiophene-2,4-diyl or thiophene-2,5-diyl; m and n are zero or one, but their sum is at most one. Even addition of only small amounts of phenanthridine derivatives of the formula (I) gives ferroelectric liquid-crystal mixtures having high negative values for the dielectric anisotropy.
摘要:
In a monostable ferroelectric active matrix display comprising a liquid-crystal layer in the form of a monodomain having an unambiguously defined direction of the layer normals z of the smC* phase, the layer normals z and the preferential direction n of the nematic or cholesteric phase (N* phase) form an angle of more than 5°.
摘要:
Compounds of the formula (I) having side chains with multiple methyl branches R.sup.1 (-A.sup.1 -M.sup.1).sub.a (-A.sup.2 -M.sup.2).sub.b (-A.sup.3 -M.sup.3).sub.c (-A.sup.4)-G(--C.sub.* H(CH.sub.3)--CH.sub.2).sub.n --R.sup.2 (I) where * is a chiral carbon atom; A.sup.1, A.sup.2, A.sup.3, A.sup.4 are, for example, 1,4-phenylene, pyrimidine-2,5-diyl or 1,3,4-thiadiazole-2,5-diyl; M.sup.1, M.sup.2, M.sup.3, M.sup.4 are, for example, --CO--O-- or --O--CO--; G is, for example, --CO--O--CH.sub.2, --O--CH.sub.2 -- or --O--; R.sup.2 is, for example, methyl or ethyl; a, b and c are 0 or 1 and a+b+c is 1, 2 or 3; and n is preferably 3 or 4, are suitable as components, in particular dopes, for liquid-crystalline mixtures and methods of using these compounds in liquid-crystal mixtures.