Inkjet Liquid Crystal Alignment Film Composition for Uniform Coating

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Solution Overview

Problem

Conventional inkjet printing methods for forming liquid crystal alignment films face issues with film thickness irregularities and poor coating properties, particularly when using materials with fluorine atoms, leading to display unevenness and quality degradation.

Innovation Solution

A composition for forming a liquid crystal alignment film is developed, comprising diethylene glycol diethyl ether, diisobutyl ketone, and at least one of γ-butyrolactone and N-methyl-2-pyrrolidone, which enhances coating properties and prevents liquid shrinkage, allowing for uniform film formation even with fluorine-containing materials.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional inkjet printing methods are used to form liquid crystal alignment films, then the process is simple and suitable for large substrates, but film thickness irregularities and poor coating properties occur, leading to display unevenness

Engineering Contradiction:

Improvesuitability for large substrate processingVSAvoidfilm thickness uniformity

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The patent changes the chemical composition parameters of the solvent system by incorporating fluorinated solvents and specific additives that modify the ink's surface tension, viscosity, and evaporation rate. This allows the ink to spread uniformly and form consistent film thickness during inkjet printing, resolving the contradiction between productivity and manufacturing precision.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses composite solvent systems combining fluorinated solvents with conventional solvents, and composite ink formulations including alignment film materials, additives, and multiple solvent components. This composite approach improves coating properties and film uniformity while maintaining inkjet printing suitability for large substrates.

Inventive Principle:

Principle #40Composite materials

2Reliability

If fluorine-containing materials are used in the alignment film composition, then liquid crystal alignment properties are improved, but liquid shrinkage and poor coating properties occur during inkjet printing

Engineering Contradiction:

Improveliquid crystal alignment propertyVSAvoidcoating property during inkjet printing

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent introduces fluorinated solvents and specific additives as intermediaries that mediate between the fluorine-containing alignment film material and the substrate. These intermediaries improve wetting and spreading while controlling evaporation, preventing liquid shrinkage, and enabling successful inkjet printing of fluorine-containing materials without compromising alignment properties.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent modifies physical parameters such as surface tension, viscosity, and evaporation rate by selecting appropriate fluorinated solvents and additives. These parameter changes enable the fluorine-containing materials to be printed uniformly via inkjet without shrinkage, while maintaining their excellent liquid crystal alignment properties.

Inventive Principle:

Principle #35Parameter changes

3Productivity

If the ink is discharged uniformly by inkjet printing, then high throughput is achieved, but film thickness irregularities occur due to drying before leveling

Engineering Contradiction:

ImprovethroughputVSAvoidfilm thickness uniformity

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The patent adjusts the evaporation rate parameter of the solvent system by using fluorinated solvents with controlled volatility. This allows the ink to remain fluid long enough to level uniformly after discharge, preventing film thickness irregularities while maintaining high throughput inkjet printing efficiency.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent incorporates additives and solvent combinations that preliminarily control the drying process to prevent premature crust formation. This preliminary action ensures uniform leveling occurs before complete drying, maintaining film thickness uniformity while preserving high productivity.

Inventive Principle:

Principle #10Preliminary action

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The composition achieves excellent coating and flatness in inkjet printing, suppressing display unevenness and enabling the formation of high-quality liquid crystal alignment films with improved liquid spreading and shrinkage properties.

Implementation Method 1

the composition achieves excellent coating and flatness in inkjet printing, suppressing display unevenness and enabling the formation of high-quality liquid crystal alignment films with improved liquid spreading and shrinkage properties

Methodology Applied

Scientific EffectLiquid spreading: Wetting

Data Source

PatentUS8057868B2Composition for forming a liquid crystal alignment film, and liquid crystal display device

Publication Date: 2011.11.15 JSR CORPORATION

AI summary

The present invention provides: a composition for forming a liquid crystal alignment film capable of forming a liquid crystal alignment film excellent in evenness; and a liquid crystal display device. The present invention provides a composition for forming a liquid crystal alignment film, wherein the composition comprises: a material for forming a liquid crystal alignment film; diethylene glycol diethyl ether; diisobutyl ketone; and at least one of γ-butyrolactone and N-methyl-2-pyrrolidone as solvents.