Liquid-crystal medium

A liquid crystal (LC) medium comprising one or more compounds selected from the compounds of formulae Y, CY, PY and LY, one or more compounds selected from the compounds of formula S1 and one or more compounds selected from the compounds of formula S2, and wherein the medium has positive dielectric anisotropy:

• wherein the individual radicals, independently of each other and on each occurrence identically or differently, have the following meanings:
• with at least one ring
• being cyclohexenylene,
• R1, R2 are, each independently, alkyl having 1 to 12 C atoms, where, in addition, one or two non-adjacent CH2 groups may be replaced by —O—, —CH═CH—, —CO—, —OCO— or —COO— in such a way that O atoms are not linked directly to one another,
• Zx, Zy are, each independently, —CH2CH2—, —CH═CH—, —CF2O—, —OCF2—, —CH2O—, —OCH2—, —CO—O—, —O—CO—, —C2F4—, —CF═CF—, —CH═CH—CH2O- or a single bond,
• L1-4 are, each independently, F, Cl, OCF3, CF3, CH3, CH2F, or CHF2,
• Ra-d are, each independently, straight chain or branched alkyl with 1 to 10 C atoms,
• X is H, CH3, OH or O●,
• A is a straight-chain, branched or cyclic alkylene with 1 to 20 C-atoms which is optionally substituted,
• a is 1 or 2,
• b is 0 or 1,
• f is 1 or 2,
• n is an integer from 1 to 6.