Liquid Crystal Display Sealant Composition for Defect Prevention
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Liquid crystal displays face issues such as image-sticking, misalignment, and decreased voltage holding ratio due to contamination from sealant ingredients, particularly with low-voltage liquid crystals, which are prone to trapping impurities like unreacted polymerization initiators and ionic substances, leading to defects like voids and alignment irregularities.
Innovation Solution
A liquid crystal display using a specific liquid crystal composition and a cured form of a curable resin composition as a sealant, where the liquid crystal composition includes compounds represented by general formula (I) and (II), and the curable resin composition contains compounds with epoxy groups, addressing contamination and improving adhesion and curing properties to prevent defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a photocurable and thermosetting sealant is used for one-drop filling, then the seal pattern can be formed and cured, but metallic wiring or black matrix overlaps with the seal pattern, shielding light for precuring and causing uncured sealant to elute into liquid crystals, leading to contamination and display defects
Solution Approach 1:
The patent extracts and eliminates the harmful components from the sealant system by using a thermosetting sealant that does not require photocuring, thereby removing the source of contamination (uncured sealant and polymerization initiators) that would otherwise elute into the liquid crystal layer and cause display defects
Solution Approach 2:
The patent introduces a thermosetting sealant as an intermediary material that replaces the photocurable sealant. This intermediary material achieves complete curing through thermal treatment without requiring light exposure, thereby preventing contamination while maintaining sealing functionality
2Use of energy by moving object
If low-voltage liquid crystals with high dielectric anisotropy are used to reduce power consumption, then power consumption is reduced, but these liquid crystals are prone to trapping impurities such as unreacted polymerization initiators and ionic impurities from the sealant, causing misalignment and decreased voltage holding ratio
Solution Approach 1:
The patent converts the potential harm of using low-voltage liquid crystals (which are sensitive to impurities) into a benefit by pairing them with a thermosetting sealant that eliminates impurity sources. The high dielectric anisotropy of the liquid crystals enables low power consumption, while the sealant modification ensures complete curing and prevents contamination, thereby maintaining high voltage holding ratio
Solution Approach 2:
The patent changes the chemical and physical parameters of the sealant system by switching from photocurable to thermosetting chemistry. This parameter change affects the curing mechanism, eliminating the need for photopolymerization and thereby removing unreacted polymerization initiators and ionic impurities that would otherwise contaminate the liquid crystal layer
3Ease of manufacture
If a thermosetting sealant made from resins that become less viscous when heated is used, then precuring through light irradiation is not needed, but the sealant still deforms partially and ingredients elute into liquid crystals during heating
Solution Approach 1:
The patent modifies the chemical composition parameters of the thermosetting sealant by incorporating specific epoxy resins and curing agents that maintain appropriate viscosity characteristics during the heating process. This parameter adjustment prevents excessive softening and deformation while ensuring complete curing, thereby maintaining seal pattern integrity
Solution Approach 2:
The patent uses a composite sealant formulation combining epoxy resin, curing agent, and adhesion promoter in specific proportions. This composite material achieves optimal balance between heat resistance (preventing deformation), adhesion (preventing elution), and curability, thereby resolving the contradiction between ease of manufacture and manufacturing precision
4Object-affected harmful factors
If epoxy resin with increased softening point is used in sealant to limit elution, then contamination is reduced, but epoxy resins are very liable to contaminate liquid crystal materials and affect adhesive strength
Solution Approach 1:
The patent employs a composite sealant system consisting of epoxy resin base, specific curing agent, and adhesion promoter. This composite formulation achieves the dual objective of reduced elution (through high softening point epoxy) and maintained adhesive strength (through the adhesion promoter component), thereby resolving the contradiction between contamination prevention and adhesion
5Strength
If acrylic modification is applied to reduce contamination and improve adhesive strength, then adhesion is improved, but thermosetting properties are affected and contamination by eluted ingredients occurs
Solution Approach 1:
The patent adjusts the chemical composition parameters by selecting specific acrylic-based epoxy resins with controlled molecular weight and functional group content. This parameter optimization maintains thermosetting properties while achieving adequate adhesion, thereby avoiding the contamination issues associated with excessive acrylic modification
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 solution effectively reduces image-sticking and misalignment, maintains a high voltage holding ratio, and provides a practical temperature range for the liquid crystal phase with large dielectric and moderate refractive index anisotropy, minimizing defects like voids and alignment irregularities.
Implementation Method 1
a sealant joining the first and second substrates together using a cured form of a curable resin composition that cures when heated
Implementation Method 2
a liquid crystal composition containing a liquid crystal composition containing one or two or more compounds represented by general formula (I)... with large dielectric and moderate refractive index anisotropy
Implementation Method 3
moderate refractive index anisotropy
Data Source
AI summary
The present invention relates to a liquid crystal display that incorporates a particular liquid crystal composition and a sealant in which a cured form of a particular curable resin composition is used. The present invention provides a liquid crystal display that prevents reduced voltage holding ratio (VHR) and increased ionic density (ID) in the liquid crystal layer and solves the problems of display defects such as voids, alignment irregularities, and image-sticking. Liquid crystal displays according to the present invention, featuring the ability to prevent reduced voltage holding ratio (VHR) in the liquid crystal layer and reduce the occurrence of display defects such as alignment irregularities and image-sticking, are useful particularly to liquid crystal displays in the IPS and FFS modes for active matrix drive and applicable to liquid crystal displays of equipment such as liquid crystal TVs, monitors, mobile phones, and smartphones.