| 主权项 |
1. A liquid-crystal medium having positive dielectric anisotropy, which comprises
a) one or more compounds of the formula I, in whichn denotes 0 or 1,R11 denotes H, F, Cl, a straight-chain or branched alkyl chain having 1-20 C atoms, in which one —CH2— group or a plurality of —CH2— groups may be replaced by —O—, —C(═O)— orbut two adjacent —CH2— groups cannot be replaced by —O—, a hydrocarbon radical which contains a cycloalkanediyl unit or an alkylcycloalkanediyl unit, and in which one —CH2— group or a plurality of —CH2— groups may be replaced by —O— or —C(═O)—, but two adjacent CH2— groups cannot be replaced by —O—,
R12 denotes H, F, Cl, CN, CF3, OCF3 or a straight-chain or branched alkyl chain having 1-20 C atoms, in which one —CH2— group or a plurality of —CH2— groups may be replaced by —O— or —C(═O)—, but two adjacent —CH2-groups cannot be replaced by —O—,Y1 denotes H, F, Cl, CN, CF3, OCF3 or a straight-chain or branched alkyl chain having 1-20 C atoms, in which one —CH2— group or a plurality of —CH2— groups may be replaced by —O— or —C(═O)—, but two adjacent —CH2-groups cannot be replaced by —O—, andon each appearance, independently of one another, denoteswhere, in the case of cyclohexanediyl and in the case of the cyclohexenediyl units, one or more H atoms may also be replaced, independently of one another, by F, Cl or CN,
and b) one or more compounds selected from the group of the compounds of the formulae II and IIIin which
R2 and R3, independently of one another, denote alkyl, alkoxy, fluorinated alkyl or fluorinated alkoxy having 1 to 7 C atoms, alkenyl, alkenyloxy, alkoxyalkyl or fluorinated alkenyl having 2 to 7 C atoms, on each appearance, independently of one another, denote L21, L22, L23 and L32, independently of one another, denote H or F, X2 and X3, independently of one another, denote halogen, halogenated alkyl or alkoxy having 1 to 3 C atoms or halogenated alkenyl or alkenyloxy having 2 or 3 C atoms, Z3 denotes —CH2CH2—, —CF2CF2—, —COO—, trans-CH═CH, trans-CF═CF—, —CH2O— or a single bond, and m and n, independently of one another, denote 0, 1, 2 or 3, and/or c) one or more compounds of the formula IVin which
R41 and R42, independently of one another, have the meaning indicated for R2 above under formula II,independently of one another, and, ifoccurs twice, also these independently of one another, denote Z41 and Z42, independently of one another and, if Z41 occurs twice, also these independently of one another, denote —CH2CH2—, —COO—, trans-CH═CH—, trans-CF═CF—, —CH2O—, —CF2O—, —C≡C— or a single bond, and p denotes 0, 1 or 2. |
