Patent ID: 8349415

Claim:
A liquid-crystalline medium having a helically twisted structure comprising: a nematic component and an optically active component, wherein said optically active component comprises one or more chiral compounds whose helical twisting power and concentration are selected in such a way that the helix pitch of the medium is ≦1 μm, and said nematic component comprises one or more compounds of formula I, in which R 1 is H or an alkyl or alkenyl radical having up to 20 carbon atoms which is unsubstituted, monosubstituted by CN or CF 3 or at least monosubstituted by halogen, and wherein one or more CH 2 groups are each, independently of one another, optionally replaced by —O—, —S—, —CO—, —CO—O—, —O—CO—, —O—CO—O—, —CH═CH— or —C≡C— in such a way that 0 atoms are not linked directly to one another, is X 0 F, Cl or alkyl, alkenyl or alkoxy each of which is halogenated and has up to 6 C-atoms, and L 1-6 are each, independently of one another, H or F.