Liquid-crystal medium

Patent metadata

Field	Value
Publication number	US-11781069-B2
Application number	US-201816225508-A
Country	US
Kind code	B2
Filing date	Dec 19, 2018
Priority date	Dec 20, 2017
Publication date	Oct 10, 2023
Grant date	Oct 10, 2023

Abstract

The present invention relates to an LC medium comprising and a liquid-crystalline host consisting of an LC component H) comprising one or more mesogenic or liquid-crystalline compounds and an optically active component D) and optionally a polymerizable component P) comprising one or more polymerizable compounds; and to the use of the polymerizable compounds and LC media for optical, electro-optical and electronic purposes, in particular in LC displays, especially in LC displays of the polymer sustained alignment type.

First claim

The invention claimed is:

1. A liquid crystal display comprising:
two substrates, at least one which is transparent to light;
an electrode provided on each substrate or two electrodes provided on only one of the substrates; and
located between the substrates a layer of a liquid-crystal medium;
the liquid-crystal medium comprising:
a liquid-crystalline host containing a liquid crystal component, and
an optically active component,

wherein the liquid crystal component comprises one or more compounds of formula CPY-n-Om, one or more compounds of formula PY-n-Om and one or more compounds of formula PYP-n-m in a total concentration in the range of from 45 to 70%:

wherein m and n are each, independently of each other, an integer from 1 to 12,
wherein the liquid crystal medium has negative dielectric anisotropy and the molecules in the layer of the liquid crystal medium in the switched-off state are aligned perpendicular to the electrode surfaces or have a tilted homeotropic alignment, the liquid-crystalline host has a chiral pitch, p, in the range of from 8 to 30 μm, the liquid crystal component has a birefringence Δn in the range of from 0.110 to 0.150;
wherein the display has a cell gap and the thickness, d, of the cell gap is in the range of from 3 μm to 5 μm; and
wherein the ratio d/p between the thickness of the cell gap d and the chiral pitch p is 0.1 to 1.

2. The liquid crystal display according to claim 1 , wherein the optically active component comprises one or more compounds selected from the formulae

in which
R a11 , R a12 and R b12 , independently of one another, denote alkyl having 1 to 15 C atoms, in which, in addition, one or more non-adjacent CH 2 groups may each be replaced, independently of one another, by —C(R z )═C(R z )—, —C≡C—, —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 or CN, with the proviso that R a12 is different from R b12 ,
R a21 and R a22 , independently of one another, denote alkyl having 1 to 15 C atoms, in which, in addition, one or more non-adjacent CH 2 groups may each be replaced, independently of one another, by —C(R z )═C(R z )—, —C≡C—, —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 or CN,
R a31 , R a31 and R b32 , independently of one another, denote straight-chain alkyl having 1 to 15 C atoms or branched alkyl having 3 to 15 C atoms, in which, in addition, one or more non-adjacent CH 2 groups may each be replaced, independently of one another, by —C(R z )═C(R z )—, —C≡C—, —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 or CN, with the proviso that R a32 is different from R b32 ,
R z denotes H, CH 3 , F, Cl, or CN,
R 8 denotes alkyl having 1 to 15 C atoms, in which, in addition, one or more non-adjacent CH 2 groups may each be replaced, independently of one another, by —C(R z )═C(R z )—, —C≡C—, —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 or CN,
Z 8 denotes —C(O)O—, —CH 2 O—, —CF 2 O— or a single bond,
A 11 is defined as A 12 below, or alternatively denotes

A 12 denotes

L 11 denotes F, Cl, —CN, P-Sp-, or straight chain alkyl having 1 to 25 C atoms, branched alkyl having 3 to 25 C atoms, or cyclic alkyl having 3 to 25 C atoms, wherein in said alkyl groups one or more non-adjacent CH 2 — groups are each optionally replaced by —O—, —S—, —CO—, —CO—O—, —O—CO—, or —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,
A 21 denotes

A 22 has one of the meanings given for A 12
A 31 has one of the meanings given for A 11 ,
alternatively denotes

A 32 has one of the meanings given for A 12 ,
n2 on each occurrence, identically or differently, is 0, 1 or 2, and
n3 is 1, 2 or 3.

3. The liquid crystal display according to claim 1 , wherein the liquid-crystalline host further comprises one or more compounds of the formulae

in which
R 11 and R 12 each, independently of one another, denote alkyl having 1 to 12 C atoms, where one or two non-adjacent CH 2 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,
L denotes F,
b denotes 0 or 1, and
r denotes 1, 2 or 3.

4. The liquid crystal display according to claim 1 , wherein the liquid-crystalline host additionally comprises one or more compounds of the following formulae:

in which
alkyl and alkyl* each, independently of one another, denote a straight-chain alkyl radical having 1-6 C atoms, and
alkenyl and alkenyl* each, independently of one another, denote a straight-chain alkenyl radical having 2-6 C atoms.

5. The liquid crystal display according to claim 1 , wherein the liquid-crystalline host additionally comprises one or more compounds of the following formula:

in which
R 5 and R 6 each, independently of one another, denote alkyl having 1 to 12 C atoms, where, in addition, one or two non-adjacent CH 2 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,

each, independently of one another, denote

in which L 5 denotes F or Cl, and L 6 denotes F, Cl, OCF 3 , CF 3 , CH 3 , CH 2 F or CHF 2 .

6. The liquid crystal display according to claim 1 , wherein the liquid-crystalline host further comprises one or more compounds of the following formula:

in which the individual radicals have the following meanings:

R 3 and R 4 each, independently of one another, denote alkyl having 1 to 12 C atoms, in which, in addition, one or two non-adjacent CH 2 groups may each be replaced by —O—, —CH═CH—, —CO—, —O—CO— or —CO—O— in such a way that O atoms are not

Assignees

• Merck Patent Gmbh

Inventors

• Liao Kirsten (Min-Chu)

Classifications

• C09K2019/0448

  the end chain group being a polymerizable end group, e.g. -Sp-P or acrylate · CPC title

• G02F1/1333

  Constructional arrangements; {Manufacturing methods}(G02F1/135, G02F1/136 take precedence) · CPC title

• C09K19/586

  Optically active dopants; chiral dopants · CPC title

• C09K19/46

  containing esters · CPC title

• C09K19/44 Primary

  containing compounds with benzene rings directly linked · CPC title