Liquid-crystal display

A liquid crystal medium comprising

• A) a liquid crystal component A comprising
• (a) one or more compounds selected from formulae A and B
• in which the individual radicals have, independently of each other and on each occurrence identically or differently, the following meanings:
• each, independently of one another, and on each occurrence, identically or differently
• R21, R31 each, independently of one another, alkyl, alkoxy, oxaalkyl or alkoxyalkyl having up to 9 C atoms or alkenyl or alkenyloxy having 2 to 9 C atoms, all of which are optionally fluorinated,
• X0 F, Cl, halogenated alkyl or alkoxy having 1 to 6 C atoms or halogenated alkenyl or alkenyloxy having 2 to 6 C atoms,
• Z31 —CH2CH2—, —CF2CF2—, —COO—, trans-CH═CH—, trans-CF═CF—, —CH2O— or a single bond,
• L21, L22, L31, L32 each, independently of one another, H or F,
• LS H or CH3, and
• g 0, 1, 2 or 3;
• (b) one or more compounds selected from formulae C and D
• in which the individual radicals have the following meanings:
• each, independently of one another, and
• on each occurrence, identically or differently
• R41, R42 each, independently of one another, alkyl, alkoxy, oxaalkyl or alkoxyalkyl having up to 9 C atoms or alkenyl or alkenyloxy having 2 to 9 C atoms, all of which are optionally fluorinated,
• Z41, Z42 each, independently of one another, —CH2CH2—, —COO—, trans-CH═CH—, trans-CF═CF—, —CH2O—, —CF2O—, —C≡C— or a single bond, and
• h 0, 1, 2 or 3;
• and
• (c) optionally one or more compounds of formula E
• in which the individual radicals, on each occurrence identically or differently, each, independently of one another, have the following meaning:
• RA1 alkenyl having 2 to 9 C atoms or, if at least one of the rings X and Y denotes cyclohexenyl, also one of the meanings of RA2,
• RA2 alkyl having 1 to 12 C atoms, in which, in addition, one or two non-adjacent CH2 groups may each be replaced by —O—, —CH═CH—, —CO—, —OCO— or —COO— in such a way that O atoms are not linked directly to one another, and
• x 1 or 2;
• B) a polymerizable component B comprising one or more polymerizable mesogenic compounds of formula I
• Ra—B1—(Zb—B2)m—Rb I
• in which the individual radicals, on each occurrence identically or differently, and each, independently of one another, have the following meaning:
• Ra and Rb P, P-Sp-, H, F, Cl, Br, I, —CN, —NO2, —NCO, —NCS, —OCN,
• —SCN, SF5 or straight-chain or branched alkyl having 1 to 25 C atoms, in which, in addition, one or more non-adjacent CH2 groups may each be replaced, independently of one another, by —C(R0)═C(R00)—, —C≡C—, —N(R00)—, —O—, —S—, —CO—, —CO—O—, —O—CO—, or —O—CO—O— in such a way that O and/or S atoms are not linked directly to one another, and in which, in addition, one or more H atoms may each be replaced by F, Cl, Br, I, CN, P or P-Sp-, where, if B1 and/or B2 contain a saturated C atom, Ra and/or Rb may also denote a radical which is spiro-linked to this saturated C atom,
• wherein at least one of the radicals Ra and Rb denotes or contains a group P or P-Sp-,
• P a polymerizable group,
• Sp a spacer group or a single bond,
• B1 and B2 an aromatic, heteroaromatic, alicyclic or heterocyclic group, having 4 to 25 ring atoms, which may also contain fused rings, and which is unsubstituted, or mono- or polysubstituted by L,
• Zb —O—, —S—, —CO—, —CO—O—, —OCO—, —O—CO—O—, —OCH2—, —CH2O—, —SCH2—, —CH2S—, —CF2O—, —OCF2—, —CF2S—, —SCF2—, —(CH2)n1—, —CF2CH2—, —CH2CF2—, —(CF2)n1—, —CH═CH—, —CF═CF—, —C≡C—, —CH═CH—COO—, —OCO—CH═CH—, CR0R00 or a single bond,
• R0 and R00 H or alkyl having 1 to 12 C atoms,
• m 0, 1, 2, 3 or 4,
• n1 1, 2, 3 or 4,
• L P, P-Sp-, OH, CH2OH, F, Cl, Br, I, —CN, —NO2, —NCO, —NCS, —OCN, —SCN, —C(═O)N(Rx)2, —C(═O)Y1, —C(═O)Rx, —N(Rx)2, optionally substituted silyl, optionally substituted aryl having 6 to 20 C atoms, or straight-chain or branched alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy having up to 25 C atoms, in which, in addition, one or more H atoms may each be replaced by F, Cl, P or P-Sp-,
• Y1 halogen, and
• Rx P, P-Sp-, H, halogen, straight-chain, branched or cyclic alkyl having up to 25 C atoms, in which, in addition, one or more non-adjacent CH2 groups may each be replaced by —O—, —S—, —CO—, —CO—O—, —O—CO—, or —O—CO—O— in such a way that O and/or S atoms are not linked directly to one another, and in which, in addition, one or more H atoms may each be replaced by F, Cl, P or P-Sp-, an optionally substituted aryl or aryloxy group having 6 to 40 C atoms, or an optionally substituted heteroaryl or heteroaryloxy group having 2 to 40 C atoms;
• C) one or more chiral additives;
• and
• D) one or more polymerization initiators, and optionally one or more stabilizers and/or self-aligning additives;
• wherein the concentration of the polymerizable mesogenic compounds in the liquid crystal medium is from 2 to 2.8% by weight,
• wherein the liquid crystal medium contains a photoinitiator,
• wherein the liquid crystal medium has a dielectric anisotropy from +4 to +15 at 20° C. and 1 kHz,
• and
• wherein the concentration of the chiral additives is selected such that the twist angle of the helical twist of the liquid crystal molecules induced by the chiral additives in the liquid crystal medium is 210-330°.