Electro-optical liquid crystal display

A medium comprising at least one compound of the formula I:

• wherein
• R1 is alkyl or alkoxy having 1 to 7 carbon atoms or alkenyl, alkenyloxy or alkoxyalkyl having 2 to 7 carbon atoms, and
• L is H or F;
• and
• at least one compound of the formula II:
• wherein
• R2 is H, alkyl or alkenyl having 1 to 15 carbon atoms which is unsubstituted, monosubstituted by CN or CF3 or at least monosubstituted by halogen, where one or more CH2 groups may also each, independently of one another, be replaced by —O—, —S—, —CO—, —CO—O—, —O—CO— or —O—CO—O— in such a way that O atoms are not linked directly to one another,
• A1 and A2 are each, independently of one another,
• (a) trans-1,4-cyclohexylene or 1,4-cyclohexenylene wherein one or more non-adjacent CH2 groups may be replaced by —O— and/or —S—,
• (b) 1,4-phenylene wherein one or two CH groups may be replaced by N,
• (c) 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,
• where (a) and (b) may be substituted by one or two fluorine atoms,
• Z1 and Z2 are each, independently of one another, —CO—O—, —O—CO—, —CH2O—, —OCH2—, —CH2CH2—, —CH═CH—, —C≡C—, —CHF—CHF—, —CF═CF—, —CF2O—, —OCF2—, —CF2CF2— or a single bond, and one of Z1 and Z2 may alternatively be —(CH2)4— or —CH═CH—CH2CH2—,
• L1 and L2 are each, independently of one another, H or F;
• and
• m is 0, 1 or 2.

A liquid-crystalline medium of positive dielectric anisotropy comprising a composition of the formula I:

• wherein
• R1 is an alkyl or alkoxy having 1 to 7 carbon atoms or alkenyl, alkenyloxy or alkoxyalkyl having 2 to 7 carbon atoms,
• and
• L is H or F.