Sealant Composition for Liquid Crystal Cells

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Solution Overview

Problem

Scanning antennas using liquid crystal compounds with an isothiocyanate group face a decrease in voltage holding ratio due to light sensitivity, leading to potential malfunction, as these compounds degrade when exposed to ultraviolet light during the one drop fill method, resulting in impurity generation and radical formation.

Innovation Solution

A sealant composition incorporating a photo-radical polymerization initiator that generates radicals when exposed to light with a wavelength of 450 nm or greater, along with a polymerization component containing polymerizable functional groups, is used to minimize degradation. This composition includes specific chemical structures that absorb longer wavelengths, preventing photodegradation of the liquid crystal compounds.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a liquid crystal compound containing an isothiocyanate group is used to achieve sufficient dielectric anisotropy in the gigahertz band, then the scanning antenna performance is improved, but the liquid crystal compound becomes sensitive to light and degrades when exposed to ultraviolet light during the one drop fill method, causing a decrease in voltage holding ratio

Engineering Contradiction:

Improvevoltage holding ratioVSAvoidlight sensitivity

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent introduces a sealant composition as an intermediary substance between the ultraviolet light source and the liquid crystal compound. This sealant contains a polymerization component and photopolymerization initiator that creates a protective barrier, absorbing or blocking ultraviolet light before it can reach and degrade the light-sensitive isothiocyanate group in the liquid crystal material, thus preventing radical formation and maintaining voltage holding ratio

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The sealant composition creates a protective environment around the liquid crystal compound during the one drop fill method. By forming a cured sealant layer that acts as a shield, it establishes a protective atmosphere that excludes harmful ultraviolet radiation from contacting the liquid crystal material, effectively creating an inert environment regarding light exposure

Inventive Principle:

Principle #39Inert atmosphere (Inert environment)

2Productivity

If light is applied to the sealant formed in a frame shape on a substrate during the one drop fill method, then the sealant curing process is accelerated, but light rays may hit the liquid crystal material within the sealed area, causing degradation and impurity generation

Engineering Contradiction:

Improvesealant curing speedVSAvoidliquid crystal compound stability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent modifies the optical parameters of the sealant composition by selecting specific photopolymerization initiators and polymerization components with appropriate absorption characteristics. These parameter changes enable the sealant to be cured by ultraviolet light while simultaneously blocking harmful wavelengths from reaching the liquid crystal compound, thus resolving the contradiction between curing speed and material stability

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The sealant composition is designed as a composite material containing multiple components: a polymerization component (such as (meth)acrylate or epoxy resin), a photopolymerization initiator, and potentially other additives. This composite structure provides both rapid curing capability and protective shielding properties, allowing the sealant to fulfill dual functions of fast setting and light protection

Inventive Principle:

Principle #40Composite materials

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 proposed sealant composition effectively reduces the decrease in voltage holding ratio, maintaining the performance and reliability of the liquid crystal cell by preventing radical formation and degradation of the liquid crystal compounds, even under high-temperature light irradiation.

Implementation Method 1

a photo-radical polymerization initiator that generates a radial when light with a wavelength of 450 nm or greater is applied

Methodology Applied

Scientific EffectPhoto-radical polymerization: Photopolymerisation

Implementation Method 2

the photo-radical polymerization initiator is configured to generate a radial when light with a wavelength of 450 nm or greater is applied

Methodology Applied

Scientific EffectRadical generation: Photodissociation

Implementation Method 3

This composition includes specific chemical structures that absorb longer wavelengths, preventing photodegradation of the liquid crystal compounds

Methodology Applied

Scientific EffectLight absorption: Absorption (EM radiation)

Implementation Method 4

a polymerization component including a polymerizable functional group polymerizable using the radical

Methodology Applied

Scientific EffectPolymerization: Photopolymerisation

Data Source

PatentUS10947416B2Sealant composition, liquid crystal cell, and method of producing liquid crystal cell

Publication Date: 2021.03.16 SHARP KK

AI summary

To provide a sealant composition with which a decrease in voltage holding rate is less likely to occur in a liquid crystal cell for a scanning antenna, the sealant composition according to the present invention includes a photo-radical polymerization initiator that generates a radical through application of light with a wavelength of 450 nm or greater and a polymerization component that contains a polymerizable functional group that is polymerizable using the radical.