Method for forming liquid crystal alignment film for photo-alignment and liquid crystal display element

A liquid crystal alignment and liquid crystal alignment agent technology, applied in liquid crystal materials, chemical instruments and methods, optics, etc., can solve the problems of reduced response speed of liquid crystal display elements, reduced brightness of liquid crystal display elements, poor alignment of liquid crystal molecules, etc.

Active Publication Date: 2016-03-30
长沙道安捷新材料有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, in the rubbing method, there are problems as follows: display defects caused by the adhesion of shavings of the alignment film generated in the step or attachment of fiber impurities, or thin-film transistors (Thin-Film-Transistor, TFT) due to static electricity. Defective display due to component damage
[0007] On the other hand, compared with the rubbing method, the photo-alignment method has lower anchoring energy and poorer alignment of liquid crystal molecules. Therefore, it has been pointed out that there are problems in that the response speed of the liquid crystal display element is reduced or burn marks are caused.
However, the photo-alignment film using polyamic acid (the polyamic acid is produced using diamine having an azo group as a raw material) has the following problems: the light transmittance is low, and the brightness of the liquid crystal display element is reduced.

Method used

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  • Method for forming liquid crystal alignment film for photo-alignment and liquid crystal display element
  • Method for forming liquid crystal alignment film for photo-alignment and liquid crystal display element
  • Method for forming liquid crystal alignment film for photo-alignment and liquid crystal display element

Examples

Experimental program
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Effect test

example

[0422] Hereinafter, the present invention is illustrated by examples. In addition, the compounds used in the examples are shown below.

[0423]

[0424] Acid dianhydride (A1): 1,2,3,4-cyclobutanetetracarboxylic dianhydride

[0425] Acid dianhydride (A2): pyromellitic dianhydride

[0426] Acid dianhydride (A3): 1,2,3,4-tetramethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride

[0427]

[0428] Diamine (D1): N,N'-bis(4-aminophenyl)-N,N'-dimethylethylenediamine

[0429] Diamine (D2): N,N'-bis(4-aminophenyl)piperazine

[0430] Diamine (D3): 4,4'-Diaminodiphenylmethane

[0431] Diamine (D4): 3,3'-Diaminodiphenylmethane

[0432] Diamine (D5): 1,4-phenylenediamine

[0433] Diamine (D6): 4,4'-Diaminoazobenzene

[0434] Diamine (D7): 4,4'-diaminodiphenylamine

[0435]

[0436] N-methyl-2-pyrrolidone: NMP

[0437] Butyl cellosolve (ethylene glycol monobutyl ether): BC

[0438]

[0439] Additive (Ad1): bis[4-(allylbicyclo[2.2.1]hept-5-ene-2,3-dicarboxyimide)phenyl]meth...

Synthetic example 1

[0445] Add 3.397g of diamine (D1) and 40.0g of dehydrated NMP into a 100mL four-neck flask equipped with a thermometer, a stirrer, a raw material inlet, and a nitrogen inlet, and stir and dissolve them under a dry nitrogen flow. Next, 1.232 g of acid dianhydride (A1), 1.370 g of acid dianhydride (A2) and 40.0 g of dehydrated NMP were added, and stirring was continued at room temperature for 24 hours. BC14.0g was added to this reaction solution, and the polyamic-acid solution whose polymer solid content concentration was 6 wt% was obtained. This polyamic acid solution was referred to as PA1. The weight average molecular weight of the polyamic acid contained in PA1 was 104,500.

[0446]The weight average molecular weight of a polyamic acid is measured by the GPC method using the 2695 separation module-2414 differential refractometer (made by Waters), and is calculated|required by polystyrene conversion. The obtained polyamic acid was diluted with the phosphoric acid-DMF mixed ...

example 1

[0453] Add a mixed solvent of NMP / BC=4 / 1 (weight ratio) to the polyamic acid solution (PA1) with a polymer solids concentration of 6wt% prepared in Synthesis Example 1, and dilute to a polymer solids concentration of 4wt % as a liquid crystal alignment agent. Using the obtained liquid crystal alignment agent, the board|substrate for transmittance evaluation was produced as shown below.

[0454]

[0455] The liquid crystal alignment agent is coated on the glass substrate by using a spinner. In addition, including the following examples and comparative examples, the rotation speed of the spinner was adjusted according to the viscosity of the liquid crystal alignment agent so that the alignment film had the following film thickness. After coating, heat and dry at 70°C for 1 minute, use RUBI color light ML-501C / B manufactured by Ushio Inc., from the vertical direction relative to the substrate, between Linearly polarized light that irradiates ultraviolet light through a polari...

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Abstract

The invention provides liquid crystal alignment agents for photo-alignment, liquid crystal photo-alignment layers, and liquid crystal displays using the same. The liquid crystal alignment agents contain tetracarboxylic dianhydride mixture including cyclopentane tetracarboxylic dianhydride, which is reacted with specific diamine to obtain polyamide acid or its derivatives. The liquid crystal alignment agents are applied to form a photo-alignment film with excellent alignment property and high light transmittance, because of light sensitivity of the chemical change caused by illumination. In addition, the photo-alignment film is applied in liquid crystal displays, the electrical characteristics required by liquid crystal alignment film is satisfied, the voltage maintaince ratio is high, the iron amount is little, the remained charge amount is little, etc.

Description

technical field [0001] The invention relates to a liquid crystal alignment agent for photo-alignment using a photo-alignment method, a photo-alignment film and a liquid crystal display element using the same. Background technique [0002] In various display devices such as monitors of personal computers, LCD TVs, viewfinders of video cameras, projection displays, and other optical print heads, optical Fourier transform Among optoelectronic-related elements such as (optical Fourier transform) elements and light valves (light valves), the mainstream of liquid crystal display elements that have been commercialized and generally distributed at present are display elements using nematic liquid crystals (nematic liquid crystal). The display modes of nematic liquid crystal display elements are widely known as TN (Twisted Nematic, twisted nematic) mode and STN (Super Twisted Nematic, super twisted nematic) mode. In recent years, in order to improve the narrow viewing angle, one of ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C09K19/56C08G73/10C08G73/12G02F1/1337
CPCC08G73/1025C08G73/1057C08G73/106C08G73/1064C08G73/1075C08G73/1085C08K5/17C08K5/25C08K5/5415C08K5/5435C08L79/08C09K19/56G02F1/133723
Inventor 松田智幸近藤史尚山内孝浩
Owner 长沙道安捷新材料有限公司
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