Polymerizable Liquid Crystal Composition for Display Afterimage Reduction
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Solution Overview
Problem
Current liquid crystal display technologies, such as PSA-VA and PSA-IPS, face challenges with limited suitability of polymerizable mesogenic units, issues with UV-induced polymerization, and difficulties in achieving optimal voltage holding ratio and pretilt angle, leading to problems like afterimages and uneven polymerization rates.
Innovation Solution
A polymerizable liquid crystal composition combining specific compounds represented by formulas I and II, with adjustable polymerization rates and improved solubility, is developed, which includes a mixture of polymerizable liquid crystal compounds and other components to enhance solubility, photoelectric properties, and voltage holding ratio, avoiding afterimages and optimizing display performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a single polymerizable liquid crystal compound is used, then the polymerization rate can be controlled, but the solubility and homogeneity are poor leading to afterimages
Solution Approach 1:
The patent uses a composite polymerizable liquid crystal composition containing multiple compounds (cyclic carbonate compound, cyclic carboxylate compound, and chain-type liquid crystal compound) to achieve both controlled polymerization rate and improved homogeneity. The cyclic compounds provide controlled polymerization while the chain-type compound ensures good solubility and homogeneity, eliminating afterimages.
2Device complexity
If UV light is used for polymerization without photoinitiator, then the process is simplified, but the choice of polymerizable compounds is limited
Solution Approach 1:
The patent selects polymerizable compounds with specific molecular structures (cyclic carbonate and cyclic carboxylate compounds) that can undergo direct UV polymerization without photoinitiators. The compounds have appropriate UV absorption characteristics and reactivity to enable direct photopolymerization, simplifying the process while maintaining versatility.
3Reliability
If high polymerization conversion is achieved, then the voltage holding ratio improves, but the pretilt angle control becomes difficult leading to display defects
Solution Approach 1:
The patent uses compounds with specific local molecular structures - cyclic carbonate and cyclic carboxylate groups that provide controlled polymerization at specific sites. This local structural特征 enables uniform pretilt angle distribution while achieving high polymerization conversion, preventing display defects.
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 high voltage holding ratio, stable pretilt angles, and reduced afterimages, simplifying LCD manufacturing and improving response speed and contrast, making it suitable for wide viewing angle applications.
Implementation Method 1
a photosensitive monomer in the liquid crystal is reacted by means of ultraviolet light
Data Source
AI summary
Provided are a polymerizable composition of a polymerizable compound represented by formula I and a polymerizable compound represented by formula II, a liquid crystal composition formed by combining this polymerizable composition with a specific liquid crystal component, particularly a PSVA liquid crystal composition suitable for display or TV applications, and a PSA-IPS liquid crystal composition for an IPS mode; in particular, the polymerizable liquid crystal composition has a good solubility, and an adjustable rate of polymerization and morphology after polymerization; furthermore, a “material system” formed from the selected polymerizable component and liquid crystal component has a low rotary viscosity and good photoelectric properties, and has a high VHR after (UV) photoradiation, this avoiding the problems of the occurrence of afterimages in final displays, etc.