Polymerizable Liquid Crystal Composition for Stable Alignment
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Solution Overview
Problem
Existing liquid crystal compositions face challenges in completely polymerizing polymerizable compounds without using a polymerization initiator, leading to residual unpolymerized compounds and alignment stability issues, which cause image sticking and degrade display quality in PSA liquid crystal display elements.
Innovation Solution
A liquid crystal composition comprising a polymerizable compound with specific structural formulas, allowing for complete polymerization without a polymerization initiator, ensuring high compatibility with liquid crystal materials and maintaining alignment stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a large amount of polymerization initiator is added to completely polymerize the polymerizable compound, then the amount of unpolymerized polymerizable compound is reduced, but the voltage-holding ratio decreases due to residual polymerization initiator
Solution Approach 1:
The invention extracts and removes the polymerization initiator from the system by using a redox polymerization mechanism where the polymerizable compound itself generates the necessary radicals through oxidation-reduction reactions with oxygen, eliminating the need for external polymerization initiators and thus avoiding residual initiator contamination
Solution Approach 2:
The polymerizable compound performs self-polymerization by utilizing oxygen from the air as an oxidizing agent, where the compound itself undergoes oxidation to generate radicals that initiate and sustain polymerization without requiring external initiators, achieving complete polymerization while maintaining high voltage-holding ratio
2Quantity of substance
If a small amount of polymerization initiator is added to reduce residual initiator, then the voltage-holding ratio is maintained, but unpolymerized polymerizable compound remains causing image sticking
Solution Approach 1:
The polymerizable compound autonomously undergoes polymerization by reacting with atmospheric oxygen through redox mechanisms, generating sufficient radicals to achieve complete polymerization without external initiators, thereby eliminating both residual initiator and unpolymerized compound
Solution Approach 2:
The invention changes the polymerization mechanism from conventional initiator-based radical polymerization to oxygen-mediated redox polymerization, altering the chemical parameters to enable complete polymerization through oxidation-reduction reactions that generate radicals in situ
3Reliability
If strong ultraviolet light is applied for a long time to completely cure the polymerizable compound, then the amount of unpolymerized polymerizable compound is reduced, but the production apparatus size increases and production efficiency decreases
Solution Approach 1:
The invention replaces the mechanical/physical ultraviolet light irradiation system with a chemical redox polymerization system that uses oxygen and ambient conditions to drive polymerization, eliminating the need for complex UV equipment and enabling complete polymerization under normal production conditions
Solution Approach 2:
The redox polymerization proceeds through periodic oxidation-reduction cycles where the polymerizable compound alternately undergoes oxidation to generate radicals and reduction to propagate polymer chains, enabling complete curing through repeated cycles without prolonged UV exposure
4Reliability
If strong ultraviolet light is applied for a long time to completely cure the polymerizable compound, then the amount of unpolymerized polymerizable compound is reduced, but degradation of the liquid crystal material occurs
Solution Approach 1:
The invention substitutes the harmful strong ultraviolet light irradiation with a gentle chemical redox polymerization process using atmospheric oxygen, eliminating UV-induced degradation of liquid crystal materials while achieving complete polymerization through oxidation-reduction reactions
Solution Approach 2:
The invention converts oxygen, which can be harmful through oxidation, into a beneficial agent that drives the redox polymerization mechanism, using controlled oxidation to generate radicals for complete polymerization without the harmful effects of UV radiation
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 achieves complete polymerization of the polymerizable compound, reducing residual unpolymerized material, enhancing alignment stability, and improving display performance by minimizing image sticking and energy requirements, thus improving production efficiency and display quality.
Implementation Method 1
a method of applying a large amount of energy may be employed, the method specifically being performed by applying strong ultraviolet light for a long time in a polymerization process
Data Source
AI summary
A liquid crystal composition containing a polymerizable compound according to the present invention is used in a liquid crystal display element in which a liquid crystal alignment capability is provided through polymerization. The liquid crystal composition contains a polymerizable compound that polymerizes without a photopolymerization initiator or with an extremely small amount of photopolymerization initiator. Therefore, the alignment properties after the polymerization become more stable and the display characteristics do not degrade. Thus, the polymerizable compound is suitable as a practical component of the liquid crystal composition. A liquid crystal display element that uses the liquid crystal composition containing a polymerizable compound according to the present invention can be suitably used for VA and IPS liquid crystal display elements.