Photo-alignment layer and liquid crystal display including the same

Patent metadata

Field	Value
Publication number	US-2016266441-A1
Application number	US-201615006760-A
Country	US
Kind code	A1
Filing date	Jan 26, 2016
Priority date	Mar 10, 2015
Publication date	Sep 15, 2016
Grant date	—

Abstract

A liquid crystal display is provided. A photo-alignment layer thereof includes a polyimide and a crosslinker including an alkylene group (—C n H 2n —, where n is a natural number) and a plurality of crosslinking end groups, wherein the plurality of crosslinking end groups include at least two types of end groups or end group derivatives, each type having a different available functional group.

First claim

What is claimed is:

1 . A photo-alignment layer comprising:
a polyimide; and a crosslinker comprising an alkylene group (—C n H 2n —, where n is a natural number) and a plurality of crosslinking end groups, wherein the plurality of crosslinking end groups comprise at least two types of end groups or end group derivatives, each type having a different available functional group.

2 . The photo-alignment layer of claim 1 , wherein the different functional groups are disposed at lateral ends of the crosslinker such that the crosslinking end groups form an asymmetrical structure.

3 . The photo-alignment layer of claim 2 , wherein the crosslinker comprises at least one compound represented by Chemical Formula 1, Chemical Formula 2, and Chemical Formula 3:

where n is a natural number of 3 to 11; m1, m2, m3, and m4 are independently a natural number of 1 to 4; A1 and A2 are independently

where R is H or an alkyl group having 1 to 3 carbon atoms, an aromatic compound having 6 to 30 carbon atoms, or an aliphatic cyclic compound having 4 to 20 carbon atoms; A3 is

an aromatic compound having 6 to 30 carbon atoms, or an aliphatic cyclic compound having 4 to 20 carbon atoms; A4 is a single bond, —CH2-, —COO—, —OCO—, —S—, —O—, an aromatic compound having 6 to 30 carbon atoms, or an aliphatic cyclic compound having 4 to 20 carbon atoms; and X1, X2, X3, X4, X5, X6, X7, X8, X9, and X10 independently include —OH, —NH 2 , an aryl group, a vinyl group,

aziridine, or carbodiimide.

4 . The photo-alignment layer of claim 3 , wherein the crosslinker comprises a compound represented by Chemical Formula 1-1:

where n is a natural number of 3 to 11.

5 . The photo-alignment layer of claim 2 , wherein the polyimide comprises a repeated unit of a compound represented by Chemical Formula 5:

where R3 is a tetravalent organic group derived from an aliphatic cyclic acid dianhydride or an aromatic acid dianhydride; and R4 is a divalent organic group derived from an aromatic diamine.

6 . The photo-alignment layer of claim 5 , wherein the polyimide is a copolymer of: (a) at least one of cyclobutane dianhydride (CBDA) and cyclobutane dianhydride (CBDA) derivatives; and (b) a first diamine.

7 . The photo-alignment layer of claim 6 , wherein the first diamine comprises a compound represented by Chemical Formula 6:

where X is —(CH 2 ) h —, —S—(CH 2 ) h —S—, —O—(CH 2 ) h —O—,

h is a natural number of 1 to 10; and h1 and h2 are a combination of natural numbers selected so that a sum of carbon atoms of an alkylene group of X is 2 to 10.

8 . The photo-alignment layer of claim 7 , wherein the copolymer further comprises a polymer of: (a) at least one of cyclobutane dianhydride (CBDA) and cyclobutane dianhydride (CBDA) derivatives; and (b) a second diamine represented by Chemical Formula 7:

9 . The photo-alignment layer of claim 8 , wherein the copolymer comprises at least one of repeated units represented by Chemical Formula 9 and Chemical Formula 10:

where X is —(CH 2 ) h —, —S—(CH 2 ) h —S—, —O—(CH 2 ) h —O—,

h is a natural number of 1 to 10; h1 and h2 are, independently, a natural number selected so that the sum of carbon atoms of an alkylene group of X is 2 to 10; and X1 to X8 are, independently, hydrogen, a halogen, an unsubstituted or substituted alkyl group, an unsubstituted or substituted aryl group, or an unsubstituted or substituted heteroaryl group.

10 . The photo-alignment layer of claim 9 , wherein the copolymer comprises a compound represented by Chemical Formula 11:

where X is —(CH 2 ) h —, —S—(CH 2 ) h —S—, —O—(CH 2 ) h —O—,

h is a natural number of 1 to 10; h1 and h2 are, independently, a natural number selected so that the sum of carbon atoms of an alkylene group of X is 2 to 10; a:b is 20:80 to 50:50; and X1 to X8 are, independently, hydrogen, a halogen, an unsubstituted or substituted alkyl group, an unsubstituted or substituted aryl group, or an unsubstituted or substituted heteroaryl group.

11 . A liquid crystal display comprising:
a first substrate; a thin film transistor disposed on the first substrate; a first electrode connected to the thin film transistor; and a first alignment layer disposed on the first electrode, wherein the first alignment layer comprises a polyimide and a crosslinker comprising an alkylene group (—C n H 2n —, n is a natural number) and a plurality of crosslinking end groups, and the plurality of crosslinking end groups comprise at least two types of end groups or end group derivatives, each type having a different available functional group.

12 . The liquid crystal display of claim 11 , wherein the different functional groups are disposed at lateral ends of the crosslinker such that the crosslinking end groups form an asymmetrical structure.

13 . The liquid crystal display of claim 12 , wherein the crosslinker comprises at least one compound represented by Chemical Formula 1, Chemical Formula 2, and Chemical Formula 3:

where n is a natural number of 3 to 11; m1, m2, m3, and m4 are independently a natural number of 1 to 4; A1 and A2 are independently

where R is H or an alkyl group having 1 to 3 carbon atoms, an aromatic compound having 6 to 30 carbon atoms or an aliphatic cyclic compound having 4 to 20 carbon atoms; A3 is

an aromatic compound having 6 to 30 carbon atoms, or an aliphatic cyclic compound having 4 to 20 carbon atoms; and A4 is a single bond, —CH2-, —COO—, —OCO—, —S—, —O—, an aromatic compound having 6 to 30 carbon atoms, or an aliphatic cyclic compound having 4 to 20 carbon atoms, and X1, X2, X3, X4, X5, X6, X7, X8, X9, and X10 independently include —OH, —NH 2 , an aryl group, a vinyl group,

aziridine, or carbodiimide.

14 . The liquid crystal display of claim 13 , wherein the crosslinker comprises a compound represented by Chemical Formula 1-1:

Assignees

• Samsung Display Co Ltd

Inventors

• Jung Jin-Soo
• Kang Suk Hoon
• Jeon Jong Hwan
• Kim In Ok
• Lee Jun Woo
• Jeon Baek Kyun

Classifications

• C08L79/08

  Polyimides; Polyester-imides; Polyamide-imides; Polyamide acids or similar polyimide precursors · CPC title

• G02F1/133788

  by light irradiation, e.g. linearly polarised light photo-polymerisation · CPC title

• G02F1/133345

  Insulating layers (G02F1/1335, G02F1/1337, G02F1/135, G02F1/136 take precedence) · CPC title

• G02F1/133723 Primary

  Polyimide, polyamide-imide · CPC title

• G02F1/134309

  characterised by their geometrical arrangement · CPC title