SiO2 Alignment Films for LCD Sealant Adhesion and Moisture Resistance

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Solution Overview

Problem

Existing liquid crystal display devices using inorganic alignment films face issues with adhesion strength and moisture resistance, leading to potential peeling and display defects, especially when using organic materials like polyimide for alignment films.

Innovation Solution

Utilizing inorganic alignment films composed of silica (SiO2) that extend over the sealant interface, enhancing adhesion through covalent bonding and minimizing moisture absorption, thereby improving the reliability and display quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If organic alignment films (polyimide) are used, then alignment uniformity is achieved, but adhesion strength is insufficient and moisture resistance is poor

Engineering Contradiction:

Improveadhesion strengthVSAvoidmoisture ingress

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the material composition parameter of the alignment film from organic (polyimide) to inorganic (silica-based), fundamentally altering the chemical properties to achieve both high adhesion strength and moisture resistance simultaneously

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The alignment film is formed as a composite structure containing silica particles dispersed in a binder resin, combining the moisture resistance of inorganic silica with the adhesive properties of the organic binder, creating a material that overcomes the limitations of pure polyimide

Inventive Principle:

Principle #40Composite materials

2Reliability

If inorganic alignment films (silica) are used, then adhesion strength and moisture resistance are improved, but manufacturing complexity increases

Engineering Contradiction:

Improvemoisture resistanceVSAvoidfilm formation process

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent replaces traditional mechanical rubbing alignment methods with a chemical alignment mechanism, where silica particles and binder resin naturally induce liquid crystal alignment through their surface properties, eliminating complex mechanical processing steps

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The alignment film is prepared in advance as a pre-formed coating containing pre-dispersed silica particles and binder resin, which is then applied to the substrate before liquid crystal injection, simplifying the overall manufacturing sequence by pre-integrating multiple functions into a single component

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 use of SiO2-based alignment films enhances adhesion strength by three times and prevents moisture ingress, reducing display defects and improving reliability and display quality.

Implementation Method 1

enhancing adhesion through covalent bonding

Methodology Applied

Scientific EffectCovalent bonding: Chemical Bonding

Implementation Method 2

minimizing moisture absorption

Methodology Applied

Scientific EffectMoisture absorption resistance: Hydrophobe

Data Source

PatentUS20250271705A1Liquid crystal display device with sealant in contact with inorganic alignment films

Publication Date: 2025.08.28 MAGNOLIA WHITE CORP

AI summary

According to one embodiment, a liquid crystal display device includes a first substrate including a first alignment film covering a pixel electrode, a second substrate including a second alignment film covering a second common electrode, a sealant attaching the first substrate and the second substrate, and a liquid crystal layer held between the first alignment film and the second alignment film, wherein the first alignment film and the second alignment film are formed of a material in which a principal chain is composed of silica (SiO2), and extend at a position overlapping the sealant between an inner face and an outer face of the sealant.