Patent ID: 7691455

Claim:
A liquid crystal medium comprising: a first dielectrically positive component, component A, comprising one or more dielectrically positive compounds of formula I wherein R 1 is alkyl having 1 to 7 C-atoms, alkoxy having 1 to 7 C-atoms, fluorinated alkyl having 1 to 7 C-atoms, fluorinated alkoxy having 1 to 7 C-atoms, alkenyl having 2 to 7 C-atoms, alkenyloxy having 2 to 7 C-atoms, alkoxyalkyl having 2 to 7 C-atoms, or fluorinated alkenyl having 2 to 7 C-atoms, are independently of each other X 1 is halogen, halogenated alkyl having 1 to 3 C-atoms, alkoxy having 1 to 3 C-atoms, halogenated alkenyl having 2 to 3 C-atoms, or alkenyloxy having 2 or 3 C-atoms; and a second dielectrically positive component, component B, comprising one or more dielectrically positive compounds, selected from compounds of formulae II and III wherein R 2 and R 3 , independently of each other, are alkyl having 1 to 7 C-atoms, alkoxy having 1 to 7 C-atoms, fluorinated alkyl having 1 to 7 C-atoms, fluorinated alkoxy having 1 to 7 C-atoms, alkenyl having 2 to 7 C-atoms, alkenyloxy having 2 to 7 C-atoms, alkoxyalkyl having 2 to 7 C-atoms, or fluorinated alkenyl having 2 to 7 C-atoms, are, independently of each other, L 21 , L 22 , L 31 and L 32 , are, independently of each other, H or F, X 2 and X 3 are, independently of each other, halogen, halogenated alkyl having 1 to 3 C-atoms, alkoxy having 1 to 3 C-atoms, halogenated alkenyl having 2 to 3 C-atoms, or alkenyloxy having 2 or 3 C-atoms, Z 3 is —CH 2 CH 2 —, —CF 2 CF 2 —, —COO—, trans- —CH═CH—, trans- —CF═CF—, —CH 2 O— or a single bond, and l, m, n and o are, independently of each other, 0 or 1, and from which compounds of formula I are excluded; and optionally a dielectrically neutral component, component C, comprising one or more dielectrically neutral compounds of formula IV wherein R 41 , and R 42 , independently of each other, are alkyl having 1 to 7 C-atoms, alkoxy having 1 to 7 C-atoms, fluorinated alkyl having 1 to 7 C-atoms, fluorinated alkoxy having 1 to 7 C-atoms, alkenyl having 2 to 7 C-atoms, alkenyloxy having 2 to 7 C-atoms, alkoxyalkyl having 2 to 7 C-atoms, or fluorinated alkenyl having 2 to 7 C-atoms, independently of each other, and in case is present twice, also these, independently of each other, are Z 41 and Z 42 are, independently of each other, and in case Z 41 is present twice, also these independently of each other, —CH 2 CH 2 —, —COO—, trans- —CH═CH—, trans- —CF═CF—, —CH 2 O—, —CF 2 O—, —C≡C— or a single bond, and p is 0, 1 or 2.