Liquid crystal medium

A liquid crystal medium comprising a) one or more compounds of formula I-2

• in which
• R1 and R2 independently of one another, denote alkyl having 1 to 7 C atoms;
• b) one or more compounds selected from the group of compounds of formulae IIA, IIB, IIC and IID
• in which
• R1A, R1B, R1C, R1D, R2A, R2B, R2C and R2D each, independently of one another, denote H, an alkyl radical having 1 to 12 C atoms or an alkenyl radical having 2 to 12 C atoms, wherein the alkyl radical or alkenyl radical is unsubstituted, monosubstituted by CN or CF3 or substituted by one or more halogens, in which one or more CH2 groups may be replaced by —O—, —S—,
• —C≡C—, —CF2O—, —OCF2—, —OC—O— or —O—CO— in such a way that o atoms are not linked directly to one another,
• L1 and L2, each, independently of one another, denote F, Cl, CF3 or CHF2,
• Y on each occurrence, identically or differently, denotes H, F, C, CF3, CHF2 or CH3,
• Z1, Z1B and Z1D each, independently of one another, denote a single bond, —CH2CH2—, —CH═CH—, —CF2O—, —OCF2—, —CH2O—, —OCH2—, —COO—, —OCO—, —C2F4—, —CF=CF— or —CH═CHCH2O—,
• p denotes 0, 1 or 2, and
• q denotes 0 or 1;
• and
• c) one or more compounds of formula III
• in which
• R31 and R32 each, independently of one another, denote H, a straight chain alkyl or alkoxy radical having 1 to 15 C atoms or a branched alkyl or alkoxy radical having 3 to 15 C atoms, where one or more CH2 groups in these radicals may each be replaced, independently of one another, by —C≡C—, —CF2O—, —OCF2—, —CH═CH—, by —O—, —CO—O— or —O—CO— in such a way that O atoms are not linked directly to one another, and in which one or more H atoms may be replaced by halogen,
• A31 on each occurrence, independently of one another, denotes
• a) 1,4-cyclohexylene or 1,4-cyclohexenylene radical, in which one or two non-adjacent CH2 groups may be replaced by —O— or —S—,
• b) a 1,4-phenylene radical, in which one or two CH groups may be replaced by N, or
• c) a radical selected from the group consisting of spiro[3.3]heptane-2,6-diyl, 1,4-bicyclo[2.2.2]octylene, naphthalene-2,6-diyl, decahydronaphthalene-2,6-diyl, 1,2,3,4-tetrahydronaphthalene-2,6-diyl, phenanthrene-2,7-diyl and fluorene-2,7-diyl,
• where the radicals a), b) and c) may be mono- or polysubstituted by halogen atoms,
• Z31 on each occurrence independently of one another denotes —CO—O—, —O—CO—, —CF2O—, —OCF2—, —CH2O—, —OCH2—, —CH2—, —CH2CH2—, —(CH2)4—, —CH═CH—CH2O—, —C2F4—, —CH2CF2—, —CF2CH2—, —CF=CF—, —CH═CF—, —CF═CH—, —CH═CH—, —C≡C— or a single bond,
• L31 and L32 each, independently of one another, denote F, Cl, CF3 or CHF2, and
• n is 0, 1 or 2;
• wherein the medium has a birefringence of 0.080 to 0.100, measured at 20° C. with light with a wavelength of 589.9 nm.