Liquid Crystal Alignment Film Inkjet Composition

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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 reduced quality.

Innovation Solution

A composition comprising 4,6-dimethyl-2-heptanone, diisobutyl ketone, and at least one of γ-butyrolactone and N-methyl-2-pyrrolidone is used, which enhances liquid spreading and prevents liquid shrinkage, improving coating properties and film flatness during inkjet printing.

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 suitable for large substrate printing, but film thickness irregularities and poor coating properties occur

Engineering Contradiction:
Improvesuitability for large substrate printingVSAvoidfilm thickness uniformity
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent changes the chemical parameters of the solvent system by selecting specific solvents (γ-butyrolactone, N-methyl-2-pyrrolidone, diisobutyl ketone) with particular boiling points and polarities. This optimization of solvent parameters enables better inkjet printing performance with reduced film thickness irregularities, resolving the contradiction between productivity and manufacturing precision.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If materials containing fluorine atoms are used in inkjet printing, then liquid crystal alignment properties are improved, but liquid repelling and shrinkage occur

Engineering Contradiction:
Improveliquid crystal alignment propertiesVSAvoidliquid repelling and shrinkage
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent employs a composite solvent system combining γ-butyrolactone, N-methyl-2-pyrrolidone, and diisobutyl ketone. This composite material approach allows the ink formulation to achieve both good wetting (preventing repelling and shrinkage) and effective delivery of fluorine-containing alignment materials, thus resolving the contradiction between reliability and harmful factors.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The optimized solvent mixture acts as an intermediary that mediates between the fluorine-containing alignment material and the substrate. The specific solvent properties facilitate uniform spreading and prevent shrinkage while still allowing the fluorine atoms to exert their alignment effect on liquid crystals.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Productivity

If inkjet printing is used for alignment film formation, then high throughput is achieved, but display unevenness occurs

Engineering Contradiction:
Improvehigh throughputVSAvoiddisplay uniformity
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent optimizes physical parameters of the ink formulation including solvent composition, boiling point range, and polarity. These parameter changes ensure uniform evaporation and film formation during high-speed inkjet printing, achieving both high throughput and display uniformity without the unevenness that plagues conventional methods.

Inventive Principle:
Principle #35Parameter changes

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 properties and flatness in liquid crystal alignment films, effectively suppressing display unevenness and preventing liquid repelling or shrinkage during inkjet printing, thereby enhancing the quality of liquid crystal display devices.

Implementation Method 1

A composition for forming a liquid crystal alignment film, wherein the composition comprises: a material for forming a liquid crystal alignment film; 4,6-dimethyl-2-heptanone; diisobutyl ketone; and at least one of γ-butyrolactone and N-methyl-2-pyrrolidone

Methodology Applied
Scientific EffectSurface tension: Surface Tension

Data Source

PatentEP2375278B1Composition for forming liquid crystal alignment film
Publication Date: 2020.04.08 SHARP KK
  • EP2375278B1 patent drawingFigure 1
  • EP2375278B1 patent drawingFigure 2(a)~2(b)
  • EP2375278B1 patent drawingFigure 3(a)~4

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; 4,6-dimethyl-2-heptanone; diisobutyl ketone; and at least one of γ-butyrolactone and N-methyl-2-pyrrolidone as solvents.