Liquid crystalline medium
AssigneeMerck Patent GmbH
InventorsBernhard Rieger, Hiroki Yoshitake, Thomas Jacob, Herbert Plach, Ulrich Finkenzeller, Hans A. Kurmeier
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Abstract
The invention relates to a liquid-crystalline medium based on a mixture of polar compounds having positive dielectric anisotropy, characterized in that it contains one or more compounds of the general formula I ##STR1## in which r is o or 1, Q.sup.1 is --CH.sub.2 CH.sub.2 -- or a single bond, A is 1,4-phenylene or trans-1,4-cyclohexylene, L is H or F, R is alkyl, alkoxy, oxaalkyl, fluoroalkyl or alkenyl, in each case having up to 7 carbon atoms and X is F, CF.sub.3, or OCF.sub.2 H.
Claims16
A liquid-crystalline medium based on a mixture of polar compounds having positive dielectric anisotropy, which comprises one or more compounds of the formula I ##STR89## in which r is 0 or 1, Q.sup.1 is --CH.sub.2 CH.sub.2 -- or a single bond, A is 1,4-phenylene or trans-1,4-cyclohexylene, L is H or F, R is alkyl, alkoxy, oxaalkyl, fluoroalkyl or alkenyl, in each case having 1 to 7 carbon atoms and X is F, OCF.sub.3 or OCF.sub.2 H, one or more compounds selected from the group consisting of the formulae II, II and IV:
- ##STR90## in which R and r are independently as defined above and the other radicals are as defined below:
- X.sup.6 :
- F, Cl, OCF.sub.3 or OCHF.sub.2,
- Y.sup.1 and Y.sup.2 :
- independently of one another, H or F, one or more compounds selected from the group consisting of the formulae V to VIII:
- ##STR91## in which R, X.sup.6, Y.sup.1 and Y.sup.2 are each independently of one another, as defined above, and
- one or more compounds selected from the group consisting of the formulae IX to XIV:
- ##STR92## in which R, X.sup.6, Y.sup.1 and Y.sup.2 are each, independently of one another, as defined above.
A liquid-crystalline medium based on terminally and laterally fluorinated compounds comprising about 10 to 25% by weight of one or more compounds from group 1:
- ##STR93## wherein R.sup.1 denotes a straight-chain alkyl group of 5 to 12 carbon atoms, L.sup.1 is H or F, X.sup.1 is F, OCF.sub.3 or OCF.sub.2 H and n is 0 or 1, about 10 to 70% by weight of one or more compounds from group 2:
- ##STR94## wherein R.sup.2 denotes a straight-chain alkyl group of 3 to 5 carbon atoms, L.sup.2 is H or F, X.sup.2 is F, OCF.sub.3 or OCF.sub.2 H, Q is ##STR95## about 5 to 40% by weight of one or more compounds of the formula Ia:
- ##STR96## wherein L.sup.3 is H or F, X.sup.3 is F, OCF.sub.3 or OCF.sub.2 H, n is 0 or 1 and ##STR97## about 0 to 15% by weight of one or more compounds from group 4:
- ##STR98## wherein L.sup.4 is H or F, about 0 to 25% by weight of one or more compounds from group 5:
- ##STR99## wherein R.sup.3 to R.sup.7 each independently denotes a straight-chain alkyl group of 1 to 12 carbon atoms, L.sup.5 is H or F, X.sup.5 is F, OCF.sub.3 or OCF.sub.2 H, and about 0 to 20% by weight of one or more compounds from group 6:
- ##STR100## wherein ##STR101## has the meaning given above for formula Ia, and R.sup.8 and R.sup.9 are each independently alkyl or alkoxy groups with one to 12 carbon atoms.
Dependencies are inferred from the claim text.