Liquid-crystal medium

1. A liquid-crystalline medium, comprising one or more compounds of formula IA

in which

R 11 and R 12 identically or differently, denote H, an alkyl or alkoxy radical having 1 to 15 C atoms, in which one or more CH 2 groups in these radicals are optionally replaced, independently of one another, by —C≡C—, —CF 2 O—, —OCF 2 —, —CH═CH—,

—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,

one or more compounds of formula BS

in which

alkyl and alkyl* identically or differently, denote alkyl having 1 to 7 C atoms, in which one or more CH 2 groups may be replaced by

and

one or more compounds selected from the group of the compounds of the formulae T-1 to T-21,

in which

R denotes a straight-chain alkyl or alkoxy radical having 1 to 6 C atoms,

(O) denotes —O— or a single bond,

m is 0, 1, 2, 3, 4, 5 or 6 and

n is 0, 1, 2, 3 or 4.

2. The liquid-crystalline medium according to claim 1 , wherein the group R 12 in formula IA denotes alkoxy having 1 to 7 C atoms.

3. The liquid-crystalline medium according to claim 1 , wherein the total concentration of the one or more compounds of the formula IA is 1% to 25% by weight and wherein the total concentration of the one or more compounds of formula BS is 7% to 20% by weight.

4. The liquid-crystalline medium according to claim 1 , wherein the medium has a birefringence of 0.110 or more, measured at 20° C. and at a wavelength of 589.3 nm.

5. The liquid-crystalline medium according to claim 1 , wherein the medium has a dielectric anisotropy of −4.5 to −12.0.

6. The liquid-crystalline medium according to claim 1 , wherein the medium comprises one or more compounds of the formulae IIA, IIB, IIC or IID,

in which

R 2A , R 2B , R 2C

and R 2D each, independently of one another, denote H, an alkyl or alkenyl radical having up to 15 C atoms which is unsubstituted, monosubstituted by CN or CF 3 or at least monosubstituted by halogen and where one or more CH 2 groups in these radicals may be replaced by —O—, —S—,

—C≡C—, —CF 2 O—, —OCF 2 —, —OC—O— or —O—CO— in such a way that O atoms are not linked directly to one another,

L 1 to L 4 each, independently of one another, denote F or Cl,

Z 2 , Z 2B , and Z 2D each, independently of one another, denote a single bond, —CH 2 CH 2 —, —CH═CH—, —CF 2 O—, —OCF 2 —, —CH 2 O—, —OCH 2 —, —COO—, —OCO—, —C 2 F 4 —, —CF═CF—, —CH═CHCH 2 O—,

p denotes 0, 1 or 2,

q denotes 0 or 1,

v denotes 1 to 6, and

(O) denotes an optional oxygen atom.

7. The liquid-crystalline medium according to claim 6 , wherein the medium additionally comprises one or more compounds of formulae O-1 to O-18,

in which

R 1 and R 2 each, independently of one another, have the meanings indicated for R 2A in claim 6 .

8. The liquid-crystalline medium according to claim 1 , wherein the medium comprises one or more polymerizable compounds of formula P

P-Sp-A 1 -(Z 1 -A 2 ) z -R  P

in which

P denotes a polymerizable group,

Sp denotes a spacer group or a single bond,

A 1 , A 2 denotes an aromatic, heteroaromatic, alicyclic or heteroaliphatic group, which may also contain fused rings, and which is unsubstituted, or mono- or polysubstituted by L,

Z 1 denotes —O—, —S—, —CO—, —CO—O—, —O—CO—, —O—CO—O—, —OCH 2 —, —CH 2 O—, —SCH 2 —, —CH 2 S—, —CF 2 O—, —OCF 2 —, —CF 2 S—, —SCF 2 —, —(CH 2 ) n1 —, —CF 2 CH 2 —, —CH 2 CF 2 —, —(CF 2 ) n1 —, —CH═CH—, —CF═CF—, —CH═CF—, —CF═CH—, —C≡C—, —CH═CH—CO—O—, —O—CO—CH═CH—, —CH 2 —CH 2 —CO—O—, —O—CO—CH 2 —CH 2 —, —CR 0 R 00 —, or a single bond,

R 0 , R 00 denotes H or alkyl having 1 to 12 C atoms,

R denotes H, L, or P-Sp-,

L denotes F, Cl, —CN, P-Sp- or C 1-25 -straight chain, C 3-25 -branched or C 3-25 -cyclic alkyl, wherein one or more non-adjacent CH 2 -groups are optionally replaced by —O—,

—S—, —CO—, —CO—O—, —O—CO—, —O—CO—O— in such a manner that O- and/or S-atoms are not directly connected with each other, and wherein one or more H atoms are each optionally replaced by P-Sp-, F or Cl,

z is 0, 1, 2 or 3, and

n1 is 1, 2, 3 or 4.

9. The liquid-crystalline medium according to claim 8 , wherein the polymerizable compounds of formula P are polymerized.

10. A process of preparing a liquid-crystalline medium according to claim 1 , comprising mixing one or more compounds of formula IA and one or more compounds of formula BS of claim 1 with one or more mesogenic or liquid-crystalline compounds and optionally with one or more polymerizable compounds of formula P

P-Sp-A 1 -(Z 1 -A 2 ) z -R  P

in which

P denotes a polymerizable group,

Sp denotes a spacer group or a single bond,

A 1 , A 2 denotes an aromatic, heteroaromatic, alicyclic or heteroaliphatic group, which may also contain fused rings, and which is unsubstituted, or mono- or polysubstituted by L,

Z 1 denotes —O—, —S—, —CO—, —CO—O—, —O—CO—, —O—CO—O—, —OCH 2 —, —CH 2 O—, —SCH 2 —, —CH 2 S—, —CF 2 O—, —OCF 2 —, —CF 2 S—, —SCF 2 —, —(CH 2 ) n1 —, —CF 2 CH 2 —, —CH 2 CF 2 —, —(CF 2 ) n1 —, —CH═CH—, —CF═CF—, —CH═CF—, —CF═CH—, —C≡C—, —CH═CH—CO—O—, —O—CO—CH═CH—, —CH 2 —CH 2 —CO—O—, —O—CO—CH 2 —CH 2 —, —CR 0 R 00 —, or a single bond,

R 0 , R 00 denotes H or alkyl having 1 to 12 C atoms,

R denotes H, L, or P-Sp-,

L denotes F, Cl, —CN, P-Sp- or C 1-25 -straight chain, C 3-25 -branched or C 3-25 -cyclic alkyl, wherein one or more non-adjacent CH 2 -groups are optionally replaced by —O—,

—S—, —CO—, —CO—O—, —O—CO—, —O—CO—O— in such a manner that O- and/or S-atoms are not directly connected with each other, and wherein one or more H atoms are each optionally replaced by P-Sp-, F or Cl,

z is 0, 1, 2 or 3, and

n1 is 1, 2, 3 or 4,

and optionally with one or more additives.

11. A liquid-crystal display comprising a medium according to claim 1 .

12. The liquid-crystal display according to claim 11 , wherein the display is a VA, IPS, U-IPS, FFS, UB-FFS, SA-FFS or SA-VA display.

13. The liquid-crystal display according to claim 11 , wherein the display is a PS-VA, PS-IPS, PS-FFS, PS-UB-FFS, polymer stabilized SA-VA or polymer stabilized SA-FFS display.