Polymerizable Liquid Crystal Composition for Stable Alignment
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Solution Overview
Problem
Existing polymerizable compound-containing liquid crystal compositions face issues with precipitation, image sticking, and slow switching speeds due to compatibility problems and lack of alignment stability, especially in PSA-type liquid crystal display devices.
Innovation Solution
A polymerizable compound-containing liquid crystal composition comprising specific polymerizable compounds and liquid crystal compounds with fluorine-substituted structures, which enhance compatibility and maintain a nematic state over a wide temperature range, allowing for fast switching and stable alignment control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a polymerizable compound with rigid structure (1,4-phenylene group or biaryl structure) is used to improve polymer rigidity and prevent image sticking, then alignment stability is improved, but compatibility with liquid crystal compounds decreases causing precipitation
Solution Approach 1:
The patent modifies the polymerizable compound structure by introducing flexible alkyl chains (specifically n-alkyl groups with 4-12 carbon atoms) between the rigid cyclic core and the polymerizable functional group. This structural parameter change maintains the rigid core for alignment stability while the flexible chains improve compatibility with liquid crystal compounds, preventing precipitation.
Solution Approach 2:
The patent creates a composite molecular structure combining a rigid cyclic hydrocarbon core (for alignment stability) with flexible alkyl chain segments (for compatibility). This composite approach allows the polymer to maintain both alignment-regulating capability and solubility in the liquid crystal composition.
2Stability of the object's composition
If dipentaerythritol pentaacrylate or dipentaerythritol hexaacrylate is used to improve polymer rigidity, then polymer structure stability is improved, but affinity for liquid crystal compounds decreases resulting in weak alignment regulation
Solution Approach 1:
The patent changes the molecular structure by incorporating cyclic hydrocarbon cores with specific rigid structures into the polymerizable compound. This structural modification enhances the compound's ability to regulate liquid crystal alignment while maintaining polymer structure stability, overcoming the weakness of acyclic polymers in alignment control.
3Speed
If liquid crystal compounds with alkenyl groups and chlorine atoms are used to improve switching speed, then switching performance is improved, but display defects increase making the device impractical
Solution Approach 1:
The patent modifies the liquid crystal compound structure by replacing chlorine atoms with fluorine atoms and optimizing alkyl chain lengths. This parameter change improves switching speed while reducing display defects, as fluorine substitution provides both fast response characteristics and better display quality without the harmful effects of chlorine.
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 ensures no precipitation, prevents image sticking, and enables fast switching with stable alignment control, maintaining a nematic state over a wide temperature range, thus providing excellent display quality and practical application in liquid crystal display devices.
Implementation Method 1
polymerizing the polymerizable compound under a condition where liquid crystal molecules are aligned by applying a voltage
Data Source
AI summary
A polymerizable compound-containing liquid crystal composition of the present invention relates to a liquid crystal composition containing a polymerizable compound represented by general formula (I) and a compound represented by general formula (II) and can be used for a liquid crystal display device imparted with liquid crystal aligning ability by polymerization. The polymerizable liquid crystal composition is required to cause no precipitation in a wide temperature range and have a low viscosity corresponding to fast switching, and a liquid crystal display device using the composition is required to have more stable alignment after polymerization and to cause no defect in display characteristics. In the present invention, the problems can be solved using a specified compound.