Liquid-crystalline medium and liquid-crystal display comprising the same

Patent metadata

Field	Value
Publication number	US-10072210-B2
Application number	US-201615097505-A
Country	US
Kind code	B2
Filing date	Apr 13, 2016
Priority date	Apr 13, 2015
Publication date	Sep 11, 2018
Grant date	Sep 11, 2018

Abstract

The invention relates to a liquid-crystalline medium, having particular dielectric properties, in that it has:
either a dielectric constant perpendicular to the director (ε ⊥ ) in the range of 2 or more to less 8 or less and at the same time a ratio of the dielectric constant perpendicular to the director (ε ⊥ ) to the dielectric anisotropy (Δε), i.e. (ε ⊥ /Δε) of 1.0 or more or or a dielectric constant perpendicular to the director (ε ⊥ ) of 8 or more and a dielectric anisotropy (Δε) of 26 or less and

preferably comprises one or more compounds having a high dielectric constant perpendicular to the director (ε ⊥ ) and a high average dielectric constant (ε av. ). These compounds are suitable for use in an electro-optical display, particularly in an active-matrix display based on the IPS or FFS effect.

First claim

The invention claimed is:

1. A liquid-crystalline medium having a nematic phase and a dielectric anisotropy (Δε) of 0.5 or more, said medium having
(a) a dielectric constant perpendicular to the director (ε ⊥ ) in the range of 2 or more to 8 or less and at the same time a ratio of the dielectric constant perpendicular to the director (ε ⊥ ) to the dielectric anisotropy (Δε), (ε ⊥ /Δε), of 1.0 or more,
or
(b) a dielectric constant perpendicular to the director (ε ⊥ ) of 8 or more and a dielectric anisotropy (Δε) of 26 or less; and

wherein said medium comprises one or more compounds having a high dielectric constant perpendicular to the director (ε ⊥ ) and a high average dielectric constant (ε av. ), which are compounds of formula I,

in which

denotes

denotes

n denotes 0 or 1,
R 11 and R 12 independently of each other denote alkyl, alkoxy, fluorinated alkyl or fluorinated alkoxy, each having 1 to 7 C atoms, alkenyl, alkenyloxy, alkoxyalkyl or fluorinated alkenyl having 2 to 7 C atoms, and R 11 alternatively denotes R 1 and R 12 alternatively denotes X 1 ,
R 1 denotes alkyl, alkoxy, fluorinated alkyl or fluorinated alkoxy having 1 to 7 C atoms, alkenyl, alkenyloxy, alkoxyalkyl or fluorinated alkenyl having 2 to 7 C atoms, and
X 1 denotes F, Cl, fluorinated alkyl, fluorinated alkenyl, fluorinated alkoxy or fluorinated alkenyloxy, the latter four groups having 1 to 4 C atoms.

2. The medium according to claim 1 , wherein said medium has a dielectric constant perpendicular to the director (ε ⊥ ) in the range of 2 or more to less 8 or less and at the same time a ratio of the dielectric constant perpendicular to the director (ε ⊥ ) to the dielectric anisotropy (Δε) of 1.0 or more.

3. The medium according to claim 1 , wherein said medium has a dielectric constant perpendicular to the director (ε ⊥ ) of 8 or more and a dielectric anisotropy (Δε) of 26 or less.

4. The liquid-crystalline medium according to claim 3 , wherein said medium has a ratio of the dielectric constant perpendicular to the director (ε ⊥ ) to the dielectric anisotropy (Δε) of 1.0 or more.

5. The liquid-crystalline medium according to claim 1 , wherein said medium has a dielectric constant perpendicular to the director (ε ⊥ ) of 20 or less.

6. The liquid-crystalline medium according to claim 5 , wherein said medium comprises one or more compounds having a high dielectric constant perpendicular to the director (ε ⊥ ) and a high average dielectric constant (ε av. ).

7. The medium according to claim 1 , wherein the total concentration of the compounds of formula I in the medium as a whole is 1% or more to 60% or less.

8. The medium according to claim 1 , wherein said medium further comprises one or more chiral compounds.

9. An electro-optical display or electro-optical component comprising a liquid-crystalline medium according to claim 1 .

10. The display according to claim 9 , wherein said display is based on the IPS- or FFS mode.

11. The display according to claim 9 , wherein said display contains an active-matrix addressing device.

12. A method of generating an electro-optical effect comprising applying voltage to a display according to claim 9 .

13. The display according to claim 9 , wherein said display is a mobile display.

14. A process for the preparation of a liquid-crystalline medium according to claim 1 , comprising mixing one or more compounds of formula I with one or more additional mesogenic compounds.

15. The medium according to claim 1 , wherein said medium has an average dielectric constant (ε av. ≡(ε ∥ +2ε ⊥ )/3) in the range from 8.0 or more to 25.0 or less.

16. The medium according to claim 15 , wherein said medium has an average dielectric constant (ε av. ≡(ε ∥ +2ε ⊥ )/3) in the range from 8.5 or more to 20.0 or less.

17. The medium according to claim 15 , wherein said medium has a dielectric constant perpendicular to the director of the liquid crystal molecules (ε ⊥ ) of 5.0 or more to 8 or less.

18. The medium according to claim 1 , wherein said medium further contains:
one or more dielectrically positive compounds selected from the compounds of formulae II and III

in which
R 2 denotes alkyl, alkoxy, fluorinated alkyl or fluorinated alkoxy having 1 to 7 C atoms, or alkenyl, alkenyloxy, alkoxyalkyl or fluorinated alkenyl having 2 to 7 C atoms,

on each appearance, independently of one another, denote

L 21 and L 22 denote H or F,
X 2 denotes halogen, halogenated alkyl or alkoxy having 1 to 3 C atoms or halogenated alkenyl or alkenyloxy having 2 or 3 C atoms,
m denotes 0, 1, 2 or 3,
R 3 denotes alkyl, alkoxy, fluorinated alkyl or fluorinated alkoxy having 1 to 7 C atoms, or alkenyl, alkenyloxy, alkoxyalkyl or fluorinated alkenyl having 2 to 7 C atoms,

on each appearance, independently of one another, are

L 31 and L 32 , independently of one another, denote H or F,
X 3 denotes halogen, halogenated alkyl or alkoxy having 1 to 3 C atoms or halogenated alkenyl or alkenyloxy having 2 or 3 C atoms,
Z 3 denotes —CH 2 CH 2 —, —CF 2 CF 2 —, —COO—, trans-CH═CH—, trans-CF═CF—, —CH 2 O— or a single bond, and
n denotes 0, 1, 2 or 3.

19. The medium according to claim 1 , wherein said medium has a dielectric ratio (ε ⊥ /Δε) of 1.5 or more.

20. The medium according to claim 18 , wherein said medium has a dielectric constant perpendicular to the director of the liquid crystal molecules (ε ⊥ ) of 9 or more.

21. The medium according to claim 18 , wherein said medium further contains one or more dielectrically neutral compounds selected from the compounds of formulae IV and V:

in which
R 41 and R 42 , independently of one another, denote alkyl, alkoxy, fluorinated alkyl or fluorinated alkoxy having 1 to 7 C atoms, or alkenyl, alkenyloxy, alkoxyalkyl or fluorinated alkenyl having 2 to 7 C atoms,

independently of one another and, if

occurs twice,
also these independently of one another, denote

Assignees

• Merck Patent Gmbh

Inventors

• Manabe Atsutaka

Classifications

• G02F1/1362

  Active matrix addressed cells {(G02F1/134336, G02F1/134363 take precedence)} · CPC title

• G02F1/134363

  for applying an electric field parallel to the substrate, i.e. in-plane switching [IPS] · CPC title

• G02F1/1333

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

• C09K2019/3422

  the heterocyclic ring being a six-membered ring · CPC title

• C09K2019/3408

  Five-membered ring with oxygen(s) in fused, bridged or spiro ring systems · CPC title