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US-12618007-B2 - Liquid-crystalline medium

US12618007B2US 12618007 B2US12618007 B2US 12618007B2US-12618007-B2

Abstract

Liquid-crystalline (LC) media or LC materials and to energy saving liquid-crystal displays (LCDs) containing these media, especially gaming displays and AR/VR headsets addressed by an active matrix and in particular LC displays of the TN, PS-TN, STN, TN-TFT, OCB, IPS, PS-IPS, FFS, HB-FFS, XB-FFS, PS-FFS, SA-HB-FFS, SA-XB-FFS, polymer stabilised SA-HB-FFS, polymer stabilised SA-XB-FFS, positive VA or positive PS-VA type.

Inventors

  • Harald Hirschmann
  • Sabine Schoen

Assignees

  • MERCK PATENT GMBH

Dates

Publication Date
20260505
Application Date
20241216
Priority Date
20231219

Claims (17)

  1. 1 . A liquid-crystalline medium containing no pleochroic dyes, comprising one or more compounds of Formula I in which the individual substituents, on each occurrence identically or differently, and each, independently of one another, have the following meaning: R 0 an alkyl group having 1 to 12 C atoms or an alkenyl group having 2 to 12 C atoms in which one or more CH 2 groups are optionally substituted by —C═C—, —CF 2 O—, —OCF 2 —, —CH═CH—, —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 substituted by a halogen atom; X 0 a halogen atom, —CN, —SCN, —NCS or an alkyl or an alkoxy group having 1 to 6 C atoms or an alkenyl or an alkenyloxy group having 2 to 6 C atoms in which one or more H atoms is substituted by a halogen atom; L 1 and L 2 each, independently of one another, H, F or Cl, wherein L 1 and L 2 do not simultaneously denote H; Y 0 H or CH 3 ; one or more compounds of Formula LP2: in which: R 0 denotes an alkyl or an alkoxy group having 1 to 12 C atoms or an alkenyl or an alkenyloxy group having 2 or 12 C atoms in which one or more non-adjacent CH 2 groups are optionally substituted by —C≡C—, —CF 2 O—, —OCF 2 —, —CH═CH—, —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 substituted by a cycloalkyl or a cycloalkoxy group having 3 to 12 C atoms; X 0 a halogen atom, —CN, —SCN, —NCS or an alkyl or an alkoxy group having 1 to 6 C atoms or an alkenyl or an alkenyloxy group having 2 to 6 C atoms in which one or more H atoms is substituted by a halogen atom; Y 0 denotes H or CH 3 ; and n denotes 0 or 1, one or more antioxidants comprising one or more compounds of Formula ST: in which the individual substituents have the following meanings: X 21 and X 22 each, independently of one another, denote —O—, —CH 2 —, —CHR 23 — or —N—R 23 —; R 21 and R 22 each, independently of one another, denote a H atom or an alkyl- or alkoxy group having 1 to 12 C atoms, an alkenyl, alkynyl, alkenyloxy or alkoxyalkyl group having 2 to 12 C atoms or a cycloalkyl group having 3 to 12 C atoms, in which one or more non-adjacent CH 2 groups are optionally substituted by —C≡C—, —CF 2 O—, —OCF 2 —, —CH═CH—, —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 substituted by a halogen atom or a cycloalkyl or a cycloalkoxy group having 3 to 12 C atoms, in which one or more H atoms may be substituted by a halogen atom; R 23 denotes a H atom, an alkyl or alkoxy group having 1 to 10 C atoms; r denotes 0 or 1 and, optionally, one or more light stabilizers comprising one or more compounds of Formula H: in which R 11 each, independently of one another, denote a H atom, F, an alkyl group having 1 to 20 C atoms, in which one or more CH 2 groups are optionally substituted by —C≡C—, —CF 2 O—, —OCF 2 —, —CH≡CH—, —O—, —CO—O—, —O—CO—, —NR 13 —, —CO—NR 13 — or —NR 13 —CO— in such a way that O and N atoms are not linked directly to one another and in which one H atom or a plurality of H atoms may be substituted by F, OR 13 , N(R 13 )(R 14 ) or R 15 ; R 12 each, independently of one another, denote a H atom, an alkyl group having 1 to 20 C atoms, in which one or more CH 2 groups are optionally substituted by —C≡C—, —CF 2 O—, —OCF 2 —, —CH≡CH—, —O—, —CO—O—, —O—CO—, —NR 13 —, —CO—NR 13 — or —NR 13 —CO— in such a way that O atoms are not linked directly to one another, a hydrocarbon group which contains a cycloalkyl or alkylcycloalkyl group and in which one or more CH 2 groups are optionally substituted by —C≡C—, —CF 2 O—, —OCF 2 —, —CH═CH—, —O—, —CO—O—, —O—CO—, —NR 13 —, —CO—NR 13 — or —NR 13 —CO— in such a way that O atoms are not linked directly to one another, and in which one H atom or a plurality of H atoms may be substituted by F, OR 13 , N(R 13 )(R 14 ) or R 15 , or an aromatic or heteroaromatic hydrocarbon group, in which one H atom or a plurality of H atoms may be substituted by OR 13 , N(R 13 )(R 14 ) or R 15 : R 13 , R 14 each, independently of one another, denote an alkyl or acyl group and R 15 having 1 to 10 C atoms or an aromatic hydrocarbon or carboxylic acid group having 6 to 12 C atoms in which one or more CH 2 groups are optionally substituted by —C≡C—, —CF 2 O—, —OCF 2 —, —CH═CH—, —O—, —CO—O—, —O—CO—, —NR 13 —, —CO—NR 13 — or —NR 13 —CO— in such a way that O atoms are not linked directly to one another; R 16 each, independently of one another, denote a H atom, an alkyl group or an alkoxy group having 1 to 10 C atoms in which one or more CH 2 groups are optionally substituted by —C═C—, —CF 2 O—, —OCF 2 —, —CH═CH—, —O—, —CO—O—, —O—CO—, —NR 13 —, —CO—NR 13 — or —NR 13 —CO— in such a way that O atoms are not linked directly to one another, O-cycloalkyl group having 3 to 12 C atoms, O′ or OH; R 17 each, independently of one another, a H atom, an alkyl group or an alkoxy group having 1 to 10 C atoms, or an alkylene group or a single bond, wherein R 17 together with S 11 may form a ring structure; S 11 and S 12 each, independently of one another, denote an alkylene group having 1 to 20 C atoms, in which one or more CH 2 groups are optionally substituted by —C≡C—, —CF 2 O—, —OCF 2 —, —CH═CH—, —O—, —CO—O—, —O—CO—, —NR 13 —, —CO—NR 13 — or —NR 13 —CO— in such a way that O and N atoms are not linked directly to one another and in which one H atom or a plurality of H atoms may be substituted by F, OR 13 , N(R 13 )(R 14 ) or R 15 , or a single bond; Y 11 to Y 14 each, independently of one another, denote methyl or ethyl; X 11 C; Z 11 to Z 14 each, independently of one another, denote —O—, —(C═O)—, —O—(C═O)—, —(C═O)—O—, —O—(C═O)—O—, —(NR 13 ), —NR 13 —(C═O)—, —(C═O)—NR 13 — or a single bond and if S 11 is a single bond, both Z 11 and Z 12 do not simultaneously denote —O—; if S 12 is a single bond, both Z 13 and Z 14 do not simultaneously denote —O—; and, if q denotes 0, both Z 12 and Z 13 do not simultaneously denote —O—; p 1 or 2; q 0 or 1; 0 (3−p); n an integer from 1 to 10; m an integer from 0 to 8; wherein n*p an integer from 1 to 10, and an organic moeity having (m+n) bonding sites.
  2. 2 . The medium according to claim 1 , wherein the one or more compounds of the Formula I is selected from one of the following: in which R 0 an alkyl group having 1 to 6 C atoms or an alkenyl group having 2 to 6 C atoms in which one or more CH 2 groups are optionally substituted by —C≡C—, —CF 2 O—, —OCF 2 —, —CH═CH—, —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 substituted by a halogen atom; X 0 a F atom or an alkyl or an alkoxy group having 1 to 3 C atoms or an alkenyl or an alkenyloxy group having 2 or 3 C atoms in which one or more H atoms are substituted by a F atom; and Y 0 H or CH 3 .
  3. 3 . The medium according to claim 1 , wherein the one or more compounds of the Formula H is selected from one of the following: in which R 11 each, independently of one another, a H atom, an alkyl group having 1 to 20 C atoms, in which one or more CH 2 groups are optionally substituted by —C≡C—, —CF 2 O—, —OCF 2 —, —CH═CH—, —O—, —CO—O— or —O—CO— in such a way that O atoms are not linked directly to one another and in which one H atom or a plurality of H atoms may be substituted by F, OR 13 , N(R 13 )(R 14 ) or R 15 ; R 16 a H atom or O*: S 11 and S 12 each, independently of one another, an alkylene group having 1 to 20 C atoms, in which one or more CH 2 groups are optionally substituted by —C≡C—, —CF 2 O—, —OCF 2 —, —CH═CH—, —O—, —CO—O— or —O—CO— in such a way that O atoms are not linked directly to one another and in which one H atom or a plurality of H atoms may be substituted by F, OR 13 , N(R 13 )(R 14 ) or R 15 , or a single bond; and n an integer from 0 to 8.
  4. 4 . The medium according to claim 1 , wherein it comprises one or more compounds selected from the following formulae: in which the individual substituents have the following meanings: “alkyl” and “alkyl*” each, independently from one another, an alkyl group having 1 to 6 C atoms; “alkenyl” and “alkenyl*” each, independently of one another, alkenyl group having 2 to 6 C atoms.
  5. 5 . The medium according to claim 1 , comprising one or more compounds selected from the group consisting of the following formulae: in which R 1 and R 2 each, independently of one another, n-alkyl, alkoxy, oxaalkyl, fluoroalkyl or alkenyl, each having up to 6 C atoms, and L 1 denotes, H, F or Cl.
  6. 6 . The medium according to claim 1 , comprising one or more compounds selected from the group consisting of the following formulae: in which the individual substituents have the following meanings: in which R 0 denotes an alkyl group having 1 to 12 C atoms or an alkenyl group having 2 to 12 C atoms in which one or more CH 2 groups are optionally substituted by —C≡C—, —CF 2 O—, —OCF 2 —, —CH═CH—, —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 substituted by a halogen atom, L 1 to L 6 denote each, independently of one another, H, F or Cl, wherein L 1 and L 2 do not simultaneously denote H, X 0 denotes a halogen atom, —CN, —SCN, —NCS or an alkyl or an alkoxy group having 1 to 6 C atoms or an alkenyl or an alkenyloxy group having 2 to 6 C atoms in which one or more H atoms is substituted by a halogen atom, and Y 0 denotes H or CH 3 .
  7. 7 . The medium according to claim 6 , wherein the one or more compounds of Formula II are selected from the following subformulae: in which R 0 denotes an alkyl group having 1 to 12 C atoms or an alkenyl group having 2 to 12 C atoms in which one or more CH, groups are optionally substituted by —C═C—, —CF 2 O—, —OCF 2 —, —CH═CH—, —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 substituted by a halogen atom, and X 0 denotes a halogen atom, —CN, —SCN, —NCS or an alkyl or an alkoxy group having 1 to 6 C atoms or an alkenyl or an alkenyloxy group having 2 to 6 C atoms in which one or more H atoms is substituted by a halogen atom.
  8. 8 . The medium according to claim 6 , wherein the one or more compounds of Formula III are selected from the following subformulae: in which R 0 denotes an alkyl group having 1 to 12 C atoms or an alkenyl group having 2 to 12 C atoms in which one or more CH 2 groups are optionally substituted by —C≡C—, —CF 2 O—, —OCF 2 —, —CH═CH—, —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 substituted by a halogen atom, and X 0 denotes a halogen atom, —CN, —SCN, —NCS or an alkyl or an alkoxy group having 1 to 6 C atoms or an alkenyl or an alkenyloxy group having 2 to 6 C atoms in which one or more H atoms is substituted by a halogen atom.
  9. 9 . The medium according to claim 1 , wherein it additionally comprises one or more compounds selected from the group consisting of the following formulae: in which R 0 denotes an alkyl group having 1 to 12 C atoms or an alkenyl group having 2 to 12 C atoms in which one or more CH 2 groups are optionally substituted by —C≡C—, —CF 2 O—, —OCF 2 —, —CH═CH—, —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 substituted by a halogen atom, X 0 denotes a halogen atom, —CN, —SCN, —NCS or an alkyl or an alkoxy group having 1 to 6 C atoms or an alkenyl or an alkenyloxy group having 2 to 6 C atoms in which one or more H atoms is substituted by a halogen atom, L 1 , L 2 denote each, independently of one another, H, F or Cl, wherein L 1 and L 2 do not simultaneously denote H, and Y 0 H or CH 3 ; L 3 and L 4 each, independently of one another, have the meanings given for L 1 ; Z 0 denotes —C 2 H 4 —, —(CH 2 ) 4 —, —CH═CH—, —CF═CF—, —C 2 F 4 —, —CH 2 CF 2 —, —CF 2 CH 2 —, —CH 2 O—, —OCH 2 —, —COO—, —CF 2 O—, or —OCF 2 —, in the Formulae V and VI also a single bond; and S denotes 0 or 1.
  10. 10 . The medium according to claim 1 , wherein it comprises one or more compounds selected from the group consisting of the following formulae in which R 0 denotes an alkyl group having 1 to 12 C atoms or an alkenyl group having 2 to 12 C atoms in which one or more CH 2 groups are optionally substituted by —C≡C—, —CF 2 O—, —OCF 2 —, —CH═CH—, —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 substituted by a halogen atom L 1 to L 4 denote each, independently of one another, H, F or Cl, wherein L 1 and L 2 do not simultaneously denote H X 0 denotes a halogen atom, —CN, —SCN, —NCS or an alkyl or an alkoxy group having 1 to 6 C atoms or an alkenyl or an alkenyloxy group having 2 to 6 C atoms in which one or more H atoms is substituted by a halogen atom, and Y 0 denotes H or CH 3 .
  11. 11 . The medium according to claim 1 , comprising one or more compounds selected from the group consisting of the following formulae: in which and in which R 1 denotes an alkyl group having 1 to 12 C atoms or an alkenyl group having 2 to 12 C atoms in which one or more CH, groups are optionally substituted by —C≡C—, —CF 2 O—, —OCF 2 —, —CH═CH—, —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 substituted by a halogen atom, and X 0 denotes a halogen atom, —CN, —SCN, —NCS or an alkyl or an alkoxy group having 1 to 6 C atoms or an alkenyl or an alkenyloxy group having 2 to 6 C atoms in which one or more H atoms is substituted by a halogen atom.
  12. 12 . The medium according to claim 1 , further comprising one or more compounds selected from the group consisting of Formulae Z1, Z2, Z3, Z4, Z5, II, III, IV, VI, XIV, XX, XII, XXIII, XXIX, XVI, XVIIa, XVIIb, and XVIIc: wherein “alkyl” and “alkyl*” each, independently from one another, denote an alkyl group having 1 to 6 C atoms; “alkenyl” and “alkenyl*” each, independently of one another, denote an alkenyl group having 2 to 6 C atoms, wherein the individual substituents, independently of each other and on each occurrence identically or differently, have the following meanings: R 0 an alkyl group having 1 to 12 C atoms or an alkenyl group having 2 to 12 C atoms in which one or more CH 2 groups are optionally substituted by —C≡C—, —CF 2 O—, —OCF 2 —, —CH═CH—, —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 substituted by a halogen atom, X 0 independently of one another F, Cl, an alkyl group or an alkoxy group having 1 to 6 C atoms or an alkenyl group or an alkenyloxy group having 2 to 6 C atoms, in which one or more H atoms is substituted by a halogen atom, L 1-8 independently of one another H, F or Cl, and Y 0 H or CH 3 , in which R 0 an alkyl group having 1 to 12 C atoms or an alkenyl group having 2 to 12 C atoms in which one or more CH 2 groups are optionally substituted by —C≡C—, —CF 2 O—, —OCF 2 —, —CH═CH—, —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 substituted by a halogen atom, X 0 independently of one another F, Cl, an alkyl group or an alkoxy group having 1 to 6 C atoms or an alkenyl group or an alkenyloxy group having 2 to 6 C atoms, in which one or more H atoms is substituted by a halogen atom, L 1-4 independently of one another H, F or Cl, Y 0 H or CH 3 , Z 0 denotes —C 2 H 4 —, —(CH 2 ) 4 —, —CH═CH—, —CF═CF—, —C 2 F 4 —, —CH 2 CF 2 —, —CF 2 CH 2 —, —CH 2 O—, —OCH 2 —, —COO—, —CF 2 O—, —OCF 2 —, or a single bond, and s denotes 0 or 1 in which R 1 and R 2 each, independently of one another, denote n-alkyl, cycloalkyl, alkoxy, oxaalkyl, or fluoroalkyl, each having up to 6 C atoms, or alkenyl having 2 to 6 C atoms, in which R 0 an alkyl group having 1 to 12 C atoms or an alkenyl group having 2 to 12 C atoms in which one or more CH 2 groups are optionally substituted by —C≡C—, —CF2O—, —OCF2-, —CH═CH—, —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 substituted by a halogen atom, X 0 independently of one another F, Cl, an alkyl group or an alkoxy group having 1 to 6 C atoms or an alkenyl group or an alkenyloxy group having 2 to 6 C atoms, in which one or more H atoms is substituted by a halogen atom, L 1-4 each, independently of one another, denote H or F, and Y 0 denotes H or CH 3 , in which R 1 and R 2 each, independently from one another, denote C 1-6 -alkyl, C 1-6 -alkoxy or C 2-6 -alkenyl, in which R 1 denotes an alkyl group having 1 to 12 C atoms or an alkenyl group having 2 to 12 C atoms in which one or more CH 2 groups are optionally substituted by —C≡C—, —CF 2 O—, —OCF 2 —, —CH═CH—, —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 substituted by a halogen atom X 0 denotes independently of one another F, Cl, an alkyl group or an alkoxy group having 1 to 6 C atoms or an alkenyl group or an alkenyloxy group having 2 to 6 C atoms, in which one or more H atoms is substituted by a halogen atom, and Y 0 H or CH 3 , in which R 1 and R 2 independently denote an alkyl group having 1 to 12 C atoms or an alkenyl group having 2 to 12 C atoms in which one or more CH 2 groups are optionally substituted by —C≡C—, —CF 2 O—, —OCF 2 —, —CH═CH—, —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 substituted by a halogen atom, and L denotes H or F, in which R 1 and R 2 independently denote an alkyl group having 1 to 12 C atoms or an alkenyl group having 2 to 12 C atoms in which one or more CH 2 groups are optionally substituted by —C═C—, —CF 2 O—, —OCF 2 —, —CH═CH—, —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 substituted by a halogen atom, and L denotes H or F.
  13. 13 . The medium according to claim 1 , further comprising one or more compounds of Formula LP1: in which: R 0 and R 2 independently denote an alkyl or an alkoxy group having 1 to 12 C atoms or an alkenyl or an alkenyloxy group having 2 or 12 C atoms in which one or more non-adjacent CH 2 groups are optionally substituted by —C≡C—, —CF 2 O—, —OCF 2 —, —CH═CH—, —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 substituted by a cycloalkyl or a cycloalkoxy group having 3 to 12 C atoms; Y 0 denotes H or CH 3 ; and m denotes 0 or 1.
  14. 14 . The medium according to claim 1 , further comprising one or more compounds selected from the group consisting of the Formulae XXIX, XXX, and XXVIIIa: in which R 1 denotes an alkyl group having 1 to 12 C atoms or an alkenyl group having 2 to 12 C atoms in which one or more CH 2 groups are optionally substituted by —C≡C—, —CF 2 O—, —OCF 2 —, —CH═CH—, —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 substituted by a halogen atom X 0 denotes independently of one another F, Cl, an alkyl group or an alkoxy group having 1 to 6 C atoms or an alkenyl group or an alkenyloxy group having 2 to 6 C atoms, in which one or more H atoms is substituted by a halogen atom, and Y 0 H or CH 3 .
  15. 15 . A process for the preparation of a liquid-crystalline medium according to claim 1 , wherein one or more antioxidants and one or more light stabilizers are mixed with one or more mesogenic compounds and optionally one or more polymerizable compounds and/or one or more additives.
  16. 16 . An electro-optical liquid-crystal display or an AR/VR headset containing a liquid-crystalline medium according to claim 1 .
  17. 17 . The electro-optical liquid-crystal display according to claim 16 , wherein it comprises a TN, PS-TN, STN, TN-TFT, OCB, IPS, PS-IPS, FFS, HB-FFS, XB-FFS, PS-HB-FFS, PS-XB-FFS, SA-HB-FFS, SA-XB-FS, polymer stabilised SA-HB-FFS, polymer stabilised SA-XB-FFS, positive VA or positive PS-VA display.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application filed under 35 U.S.C. § 111(a) claims priority benefit under 35 U.S.C. § 119(a) of and to EP Patent Application No. 23218161.0, filed Dec. 19, 2023, the entire contents of which are incorporated herein by reference in their entirety and for all purposes. BACKGROUND OF THE INVENTION The present invention relates to liquid-crystalline (LC) media and to energy saving liquid-crystal displays (LCDs) containing these media, especially to high contrast, fast switching gaming displays and AR/VR headsets having reduced short term image sticking and reduced long term image sticking especially after light load and/or temperature load. In particular, it relates to LC displays of the TN, PS-TN, STN, TN-TFT, OCB, IPS, PS-IPS, FFS, HB-FFS, XB-FFS, PS-FFS, SA-HB-FFS, SA-XB-FFS, polymer stabilised SA-HB-FFS, polymer stabilised SA-XB-FFS, positive VA or positive PS-VA type. In a preferred embodiment, the LC media have positive dielectric anisotropy. LCDs are used in many areas for the display of information. LCDs are used both for direct-view displays and for projection-type displays. The electro-optical modes used are, for example, the twisted nematic (TN), super twisted nematic (STN), optically compensated bend (OCB) and electrically controlled birefringence (ECB) modes together with their various modifications, as well as others. All these modes utilise an electric field which generated substantially perpendicular to the substrates and the LC layer. Besides these modes, there are also electro-optical modes that utilise an electric field which is substantially parallel to the substrates or the LC layer. For example, WO 91/10936 discloses a LC display in which the electric signals are generated in such a way that the electric fields have a significant component parallel to the LC layer, and which has since then become known as “in-plane switching” (IPS) display. The principles of operating such a display are described, for example, by R. A. Soref in Journal of Applied Physics, Vol. 45, No. 12, pp. 5466-5468 (1974). IPS displays contain an LC layer between two substrates with planar orientation, where the two electrodes are arranged on only one of the two substrates and preferably have interdigitated, comb-shaped structures. On application of a voltage to the electrodes an electric field with a significant component parallel to the LC layer is generated between them. This causes realignment of the LC molecules in the layer plane. EP 0 588 568, for example, discloses various possibilities for the design of the electrodes and for addressing an IPS display. DE 198 24 137 likewise describes various embodiments of such IPS displays. LC materials for IPS displays of this type are described, for example, in DE 195 28 104. Furthermore, so-called “fringe-field switching” (FFS) displays have been reported (see, inter alia S. H. Jung et al., Jpn. J. Appl. Phys., Volume 43, No. 3, 2004, 1028), which contain two electrodes on the same substrate, one of which is structured in a comb-shaped manner and the other is unstructured. A strong, so-called “fringe field” is thereby generated, i.e. a strong electric field close to the edge of the electrodes, and, throughout the cell, an electric field which has both a strong vertical component and also a strong horizontal component. FFS displays have a low viewing-angle dependence of the contrast. FFS displays usually contain an LC medium with positive dielectric anisotropy, and an alignment layer, usually of polyimide, which provides planar alignment to the molecules of the LC medium. LCDs of the IPS and FFS electro-optical mode are, in particular, suitable for use in modern desktop monitors, TV sets and multimedia applications. The LC media according to the present invention are preferably used in displays of this type. In general, dielectrically positive LC media having rather lower values of the dielectric anisotropy are used in FFS displays, but in some cases LC media having a dielectric anisotropy of only about 3 or even less are also used in IPS displays. A further improvement has been achieved by the HB-FFS mode. One of the unique features of the HB-FFS mode in contrast to the traditional FFS technology is that it enables higher transmittance which allows operation of the panel with less energy consumption. Another recently developed mode is the XB-FFS mode, wherein the LC medium additionally contains a polar liquid crystal compound with low dielectric anisotropy. FFS and IPS displays can be operated as active-matrix displays (AMD) or passive-matrix displays (PMD). In the case of active-matrix displays individual pixels are usually addressed by integrated, non-linear active elements such as, for example, thin-film transistors (TFTs), while in the case of passive-matrix displays individual pixels are usually addressed by the multiplex method as known from the prior art. The displays according to the present invention are preferably addr