Polymerizable Liquid Crystal Composition for Image Sticking Resistance
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Solution Overview
Problem
PSA-type liquid crystal display devices face issues with image sticking due to changes in pre-tilt angles of liquid crystal molecules, low compatibility between polymerizable and liquid crystal compounds leading to precipitation, and unsatisfactory response speed, along with reliability concerns from chlorine-containing compounds.
Innovation Solution
A polymerizable compound-containing liquid crystal composition comprising specific compounds represented by general formulas (I), (II), (III), and (IV) that ensure compatibility, stability, and high polymerization rates, preventing precipitation and improving alignment stability and response speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a polymerizable compound with high rigidity (1,4-phenylene group or biaryl structure) is used to prevent image sticking, then image sticking resistance 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 (3-10 carbon atoms) between the rigid aromatic rings. This parameter change in molecular structure maintains the rigidity needed for image sticking resistance while adding flexibility that improves compatibility with liquid crystal compounds, preventing precipitation.
Solution Approach 2:
The patent creates a composite molecular structure combining rigid aromatic rings (for image sticking resistance) with flexible alkyl chains (for compatibility). This composite approach allows the polymerizable compound to simultaneously achieve both required properties that cannot be obtained with单一 structures.
2Speed
If various combinations of liquid crystal compositions and polymerizable compounds are used to improve response speed, then response speed is improved, but voltage reduction is still required and chlorine atoms are released by UV irradiation decreasing reliability
Solution Approach 1:
The patent replaces harmful chlorine atoms with fluorine atoms in the liquid crystal compound structure. Fluorine atoms provide similar electronic properties for maintaining response speed but offer superior stability against UV irradiation, converting the reliability problem into a solution.
3Strength
If polymerizable compounds with ring structures and polymerizable functional groups are used to increase polymer rigidity, then polymer rigidity is improved, but compatibility with liquid crystal compounds is low leading to precipitation
Solution Approach 1:
The patent changes the molecular parameters by introducing flexible alkyl chains (3-10 carbon atoms) into the polymerizable compound structure. This maintains the rigid aromatic ring structure for polymer strength while the flexible chains improve compatibility with liquid crystal compounds, preventing precipitation.
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 provides a stable liquid crystal composition with high alignment regulating force, preventing image sticking and display defects, while maintaining nematic state stability and reducing adverse effects from UV irradiation, thus enhancing display quality and manufacturing efficiency.
Implementation Method 1
polymerizing the polymerizable compound under a condition where liquid crystal molecules are aligned by applying a voltage, thereby fixing the alignment of the liquid crystal molecules
Data Source
AI summary
A polymerizable compound-containing liquid crystal composition includes at least one of compounds represented by general formulae (I) to (IV). A liquid crystal display device uses the liquid crystal composition.