Polymerizable Compound Alignment for Liquid Crystal Displays
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Solution Overview
Problem
Current polymerizable compounds for liquid crystal display devices lack excellent alignment capability, suitable polymerization reactivity, high conversion rates, and high solubility, which limits their ability to achieve optimal physical properties such as high maximum temperature, low minimum temperature, low viscosity, and suitable optical and dielectric anisotropy.
Innovation Solution
A polymerizable compound with a specific monovalent group structure, represented by formula (A), which allows for improved solubility, polymerization reactivity, and alignment of liquid crystal molecules, enabling a balance of physical properties like high maximum temperature, low minimum temperature, and suitable anisotropy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional polymerizable compounds are used in liquid crystal display devices, then the device can be manufactured, but the alignment capability of liquid crystal molecules is insufficient and physical properties cannot be optimized
Solution Approach 1:
The patent modifies the molecular structure of polymerizable compounds by introducing specific functional groups (cyano, fluoro, alkoxy) and adjusting molecular weight and polarity parameters to achieve optimal alignment capability and physical properties including high maximum temperature, low minimum temperature, and suitable anisotropy
Solution Approach 2:
The patent creates composite liquid crystal compositions by combining polymerizable compounds with liquid crystal molecules, where the polymerizable compound serves multiple functions: alignment promoter, polymer matrix former, and physical property modifier, achieving synergistic effects that improve both alignment capability and overall device performance
2Productivity
If polymerizable compounds with high polymerization reactivity are used, then conversion rate increases, but solubility in liquid crystal composition decreases
Solution Approach 1:
The patent balances polymerization reactivity and solubility by adjusting molecular weight, introducing flexible alkyl chains, and selecting appropriate functional groups that maintain both high conversion rate upon UV irradiation and adequate solubility in the liquid crystal composition before polymerization
Solution Approach 2:
The polymerizable compound acts as an intermediary substance that remains soluble in the liquid crystal composition during storage and injection, then undergoes polymerization upon UV irradiation to form the alignment-stabilizing polymer network, bridging the requirements for both solubility and reactivity
3Reliability
If alignment film is used in liquid crystal display devices, then initial alignment is achieved, but electric resistance increases due to interaction between alignment film and composition
Solution Approach 1:
The patent extracts and eliminates the alignment film component from the device structure by using polymerizable compounds that provide alignment functionality through chemical polymerization within the liquid crystal composition itself, removing the source of electric resistance problems
Solution Approach 2:
The liquid crystal composition performs self-alignment through the polymerizable compound that polymerizes in situ to create the alignment structure, eliminating the need for separate alignment film layers and reducing interfacial resistance issues
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 compound provides a liquid crystal composite with enhanced alignment, short response time, wide temperature range, large voltage holding ratio, low threshold voltage, and long service life in liquid crystal display devices.
Implementation Method 1
Next, the composition is irradiated with ultraviolet light. Here, the polymerizable compound or the polymerizable polar compound is polymerized.
Data Source
AI summary
Provided are a polymerizable compound having at least one monovalent group (A), a polymerizable composition containing the polymerizable compound, a liquid crystal composite prepared from the polymerizable composition, and a liquid crystal device having the polymerizable composition.In monovalent group (A), R1 and R2 are independently hydrogen, halogen or alkyl having 1 to 20 carbons, and in the alkyl, at least one piece of —CH2— may be replaced by —O— or —S—, and at least one piece of —(CH2)2— may be replaced by —CH═CH—, and in the groups, at least one hydrogen may be replaced by halogen.