Patent ID: 8043671

Claim:
A liquid-crystalline medium based on a mixture of dielectrically negative polar compounds, comprising one or more compounds of formula I in which R 11 and R 12 each independently of one another denote H, an unsubstituted alkyl or alkenyl radical having up to 15 C atoms in which one or more CH 2 groups may be replaced by —O—, —S—, —C≡C—, —CF 2 —O—, —O—CF 2 —, —CO—O— or —O—CO— in such a way that O atoms are not linked directly to one another, one of the rings which is present, denotes and another one of these rings, which is present, denotes and the last one, if present, independently of the others, denotes Z 11 and Z 12 each independently of one another denote —CH 2 —CH 2 —, —CH═CH—, —C≡C—, —CH 2 —O—, —O—CH 2 —, —CO—O—, —O—CO—, —CF 2 —O—, —O—CF 2 —, —CF 2 —CF 2 — or a single bond, and m denotes 0 or 1, and one or more compounds of the formula II in which R 21 and R22 each independently of one another denote H, an unsubstituted alkyl or alkenyl radical having up to 15 C atoms in which one or more CH 2 groups may be replaced by —O—, —S—, —C≡C—, —CF 2 —O—, —O—CF 2 —, —CO—O— or —O—CO— in such a way that O atoms are not linked directly to one another, denotes independently of one another denote Z 2 denotes —CH 2 —CH 2 —, —CH═CH—, —C≡C—, —CH 2 —O—, —O—CH 2 —, —CO—O—, —O—CO—, —CF 2 —O—, —O—CF 2 —, —CF 2 —CF 2 —or a single bond, and n denotes 0 or 1.