Liquid Crystal Display Polymer Layer Amide Group Water Trapping
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Solution Overview
Problem
Liquid crystal display devices with polymer sustained alignment (PSA) treatments experience discolorations and display irregularities when used in high temperature or high humidity environments, primarily due to water moisture and impurities from sealing materials entering the liquid crystal layer.
Innovation Solution
Incorporating a radical-polymerizable monomer with an amide group into the liquid crystal composition between the substrates and polymerizing it using UV light to form a polymer layer that effectively interacts with and traps water and impurities, maintaining the alignment of liquid crystal molecules and preventing their ingress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional PSA treatment is used to control liquid crystal alignment, then the alignment is maintained, but water moisture and impurities from sealing materials enter the liquid crystal layer causing discolorations and display irregularities in high temperature or high humidity environments
Solution Approach 1:
The patent converts the harmful effect of water moisture and impurities into a beneficial effect by using their polarity to interact with the polar amide groups in the monomer. The amide groups form hydrogen bonds with water molecules and strong dipole-dipole interactions with polar impurities, trapping these harmful substances within the polymer layer and preventing them from entering the liquid crystal layer, thus eliminating discolorations and display irregularities
Solution Approach 2:
The patent changes the chemical parameter of the monomer by introducing an amide group with high polarity. This parameter change enables the monomer to form strong interactions with polar molecules like water and impurities through hydrogen bonding and dipole-dipole interactions, significantly enhancing the polymer layer's ability to trap and retain these substances, thereby preventing their ingress into the liquid crystal layer and maintaining display quality
2Stability of the object's composition
If a polymer layer is formed by polymerizing a monomer in the liquid crystal layer, then liquid crystal alignment is controlled, but the polymerization process and monomer selection affect the overall device performance and stability
Solution Approach 1:
The patent changes the chemical parameter of the monomer by introducing an amide group with high polarity. This parameter change enables the monomer to form strong interactions with polar molecules like water and impurities, significantly enhancing the polymer layer's ability to trap and retain these substances, thereby preventing their ingress into the liquid crystal layer and maintaining display quality
Solution Approach 2:
The patent creates a composite system by combining the liquid crystal material with a radical-polymerizable monomer containing an amide group. This composite liquid crystal composition allows the formed polymer layer to possess both alignment control functionality and enhanced impurity trapping capability, improving overall device reliability and performance
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
This solution significantly reduces discolorations and display irregularities, ensuring high display quality even in harsh environmental conditions by forming strong interactions with polar molecules and hydrogen bonding with water and impurities, thus maintaining the voltage holding ratio and image quality.
Implementation Method 1
irradiating the assembly with light (such as UV light) to polymerize the polymerizable ingredient (the monomer, oligomer, or the like)
Implementation Method 2
the amide group (—NHCO—) has a nitrogen atom and can form hydrogen bonds with hydrogen-bonding polar molecules such as water through the hydrogen atom bonded to the nitrogen atom
Implementation Method 3
an extremely strong dipole-dipole interaction occurs between the —CO— group within the amide group and other polar molecules
Data Source
AI summary
A liquid crystal display device includes: a polymer layer that controls the alignment of liquid crystal molecules on at least one of the first substrate and the second substrate. The polymer layer is formed by polymerizing one or more radical-polymerizable monomers added to the liquid crystal layer. At least one of the radical-polymerizable monomers is a compound represented by P-Sp1-Z2-A1-(Z1-A2)n1-Z3-Sp2-P. In an example encompassed by the formula, P represents a radical-polymerizable group. Sp1 and Sp2 each represent a direct bond or an alkylene group. A1 represents a divalent aromatic hydrocarbon group. A2 represents a phenylene group. Z1, Z2, and Z3 may be the same or different. At least one of Z1, Z2, and Z3 represents a direct bond, or an —NRCO— group or —CONR— group. R represents a hydrogen atom or a C1-C6 linear alkyl group or alkenyl group. n1 is 0 or 1.