Alignment film, method for preparing the same and liquid crystal display device comprising the same

Patent metadata

Field	Value
Publication number	US-9701793-B2
Application number	US-201314387029-A
Country	US
Kind code	B2
Filing date	Nov 12, 2013
Priority date	May 31, 2013
Publication date	Jul 11, 2017
Grant date	Jul 11, 2017

Abstract

An alignment film, a method for preparing the same, a liquid crystal display device including the alignment film. The alignment film is an oriented polyimide film. The method for preparing the alignment film includes: adding a bridging diphenyl diamine to N-methylpyrrolidinone, followed by the addition of 1,4,5,8-naphthalenetetracarboxylic dianhydride to allow the reaction to occur, and filtering the reaction mixture to give a liquid polyamide acid; dissolving the liquid polyamide acid into N-methylpyrrolidinone to give a solution, which is coated onto the surface of a substrate and subjected to a heat treatment, to produce a polyimide film; and orienting the polyimide film via an orientation process to form an alignment film, wherein, polyimide has a structure represented by Formula-4:

wherein, R is a strong electron withdrawing group, each of R 1 and R 2 is independently methyl, ethyl, propyl, isopropyl, methoxy, ethoxy, propoxy, or isopropoxy, The polyimide film has good optical transmittance.

First claim

The invention claimed is:

1. An alignment film, which is formed by polyimide, wherein the polyimide has a structure represented by Formula-4:

wherein, R is S, O, SO 2 , CCl 2 , or CF 2 , each of R 1 and R 2 is independently methyl, ethyl, propyl, isopropyl, methoxy, ethoxy, propoxy, or isopropoxy.

2. The alignment film of claim 1 , wherein said polyimide is produced by reacting 1,4,5,8-naphthalenetetracarboxylic dianhydride represented by Formula-1 with bridging diphenyl diamine represented by Formula-2,

wherein in Formula-2, R is S, O, SO 2 , CCl 2 , or CF 2 , each of R 1 and R 2 is independently methyl, ethyl, propyl, isopropyl, methoxy, ethoxy, propoxy, or isopropoxy.

3. A method for preparing an alignment film comprises:
(1) adding a bridging diphenyl diamine represented by Formula-2 to N-methylpyrrolidinone, followed by the addition of 1,4,5,8-naphthalenetetracarboxylic dianhydride represented by Formula-1 to allow the reaction to occur, and filtering the reaction mixture to give a liquid polyamide acid,

in Formula-2, R is S, O, SO 2 , CCl 2 , or CF 2 , each of R 1 and R 2 is independently methyl, ethyl, propyl, isopropyl, methoxy, ethoxy, propoxy, or isopropoxy;
(2) dissolving the liquid polyamide acid into N-methylpyrrolidinone to give a solution, which is coated onto the surface of a substrate and subjected to a heat treatment, to produce a polyimide film; and
(3) orienting the polyimide film via an orientation process to form an alignment film,
wherein, polyimide has a structure represented by Formula-4:

4. The method for preparing an alignment film of claim 3 , wherein step (1) occurs at room temperature.

5. The method for preparing an alignment film of claim 3 , wherein the heat treatment in step (2) includes: heating for 3-6 minutes at 90-100° C., and then heating for 40-80 minutes at 220-250° C.

6. The method for preparing an alignment film of claim 3 , wherein the orientation process in step (3) is a rubbing orientation process.

7. A liquid crystal display device, having an array substrate or a color substrate on which the alignment film of claim 1 is formed.

Assignees

• Xiao Ang
• Wang Shanshan
• Boe Technology Group Co Ltd
• Beijing Boe Optoelectronics Tech Co Ltd

Inventors

• Xiao Ang
• Wang Shanshan

Classifications

• C09D179/08

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

• C08G73/1039

  comprising halogen-containing substituents · CPC title

• Y10T428/1005

  Cross-Sectional Technologies · mapped topic

• C08G73/105

  with oxygen only in the diamino moiety · CPC title

• C08G73/1071

  Wholly aromatic polyimides containing oxygen in the form of ether bonds in the main chain · CPC title