Liquid Crystal Medium Composition for PSVA Alignment Control
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Solution Overview
Problem
Conventional polymer stabilized vertical alignment (PSVA) techniques in liquid crystal displays face challenges in controlling the degree of polymerization and size of polymerized particles, leading to poor alignment and reduced optic performance, including bright spots in the dark state and reduced contrast.
Innovation Solution
A liquid crystal medium composition comprising two or more polymerizable monomers that undergo polymerization under UV radiation, with specific structural formulas and ratios, is used to control the size and homogeneity of polymer bumps, preventing poor alignment and dark-state bright spots, and enhancing optic performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a single type of polymerizable monomer is used in PSVA technique, then the process is simple, but the polymer bumps formed are excessively large and non-uniform due to variation in light irradiation conditions, leading to poor alignment and reduced contrast
Solution Approach 1:
The patent divides the single monomer system into multiple monomer components (typically two or more different polymerizable monomers with different reactivity ratios). This segmentation allows each monomer to contribute differently to the polymerization process, ensuring that even when light irradiation varies, the resulting polymer bumps remain small, uniform in size, and evenly distributed. The different monomers compensate for each other's reactivity differences, maintaining consistency in bump formation.
Solution Approach 2:
The patent uses a composite monomer system comprising multiple types of polymerizable monomers rather than a single monomer. This composite approach creates a more robust polymerization system where the different monomers work together to produce polymer bumps with controlled size and uniform distribution. The composite formulation ensures that variations in light irradiation intensity do not lead to excessive polymerization or non-uniform bump formation.
2Productivity
If strong intensity irradiation light is applied to accelerate RM reaction rate, then productivity increases, but excessively large polymer particles are formed causing poor alignment, undersize spots, leakage in dark state, and reduced contrast
Solution Approach 1:
The patent changes the chemical parameters of the polymerizable monomer system by using multiple monomers with different reactivity characteristics instead of a single monomer. This parameter change in the monomer composition allows the system to tolerate a wider range of light irradiation intensities without forming excessively large particles. The different monomers have different polymerization rates, which balance each other out to maintain controlled particle size even under strong irradiation conditions.
3Manufacturing precision
If weak intensity irradiation light is applied to slow down RM reaction rate, then polymer particle size is controlled, but manufacturing time increases and productivity decreases
Solution Approach 1:
The patent modifies the chemical parameters of the polymerization system by incorporating multiple monomers with different reactivity ratios. This allows the system to achieve controlled particle size formation without requiring extremely weak light irradiation. The less reactive monomer slows down the overall polymerization rate to prevent excessive particle growth, while the more reactive monomer ensures the reaction still proceeds at a practical speed, thus balancing precision and productivity.
4Reliability
If polymer bumps are formed to guide liquid crystal alignment, then alignment effect is achieved, but excessively large or non-uniform bumps cause poor alignment, dark-state bright spots, and reduced optic performance
Solution Approach 1:
The patent segments the polymerization process by using multiple monomer types that polymerize at different rates and to different extents. This segmentation ensures that the resulting polymer bumps are small, uniform, and evenly distributed throughout the liquid crystal medium. The uniform bump structure provides consistent alignment guidance for liquid crystal molecules, preventing defects such as dark-state bright spots and ensuring high optic performance.
Solution Approach 2:
The patent employs a composite monomer system that produces polymer bumps with optimized size and uniformity. The different monomers in the composite system work synergistically to form bumps that are small enough to provide precise alignment guidance but uniform enough to avoid creating optical defects. This composite approach ensures reliable liquid crystal alignment while maintaining excellent optic performance including high contrast and fast response.
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 small, homogeneous polymer bumps, preventing poor alignment and dark-state issues, resulting in high contrast and fast response rates for liquid crystal panels.
Implementation Method 1
two or more than two polymerizable monomers that undergo polymerization reactions when irradiated by ultraviolet light
Data Source
AI summary
The present invention provides a liquid crystal medium composition for use in liquid crystal display, which includes the following constituent components: a negative type liquid crystal material, a stabilizer, and two or more than two polymerizable monomers that undergo polymerization reactions under UV radiation. The polymerizable monomers are in an amount of 0.1-1% by weight based on total weight of the liquid crystal medium composition. The polymerizable monomers have a structural formula composed of a single benzene ring, two benzene rings, or a naphthalene ring. The structural formula composed of two benzene rings is formed by two benzene rings that are directly linked or linked via a moiety. The benzene ring and naphthalene ring are directly linked at least one polymerizable moiety. Through use of two or more than two polymerizable monomers in the liquid crystal medium composition, polymer bumps having a small size and excellent homogeneity can be obtained.