Liquid Crystal Composition for Fast Pre-Tilt and High VHR
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Solution Overview
Problem
Existing liquid crystal compositions face challenges in achieving balanced pre-tilt angle formation speed, complete polymerization, and stability, leading to issues like image sticking and uneven display quality, especially in large-size LCD panels.
Innovation Solution
A liquid crystal composition comprising specific compounds of general formulas I, II, M, N, and A, designed to enhance dielectric anisotropy, K value, low-temperature storage, and pre-tilt angle stability, with optimized polymerizable groups and spacers for faster and more controlled polymerization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If shorter wavelength UV1 radiation is used to improve pre-tilt angle formation speed, then the speed for forming pre-tilt angle is improved, but the voltage holding ratio decreases
Solution Approach 1:
The patent modifies the chemical structure of polymerizable compounds by introducing specific molecular groups (cyclic carbonate groups, cyclic carboxylate groups) and adjusting spacer lengths to optimize UV absorption characteristics and polymerization kinetics, enabling faster pre-tilt angle formation while maintaining voltage holding ratio
Solution Approach 2:
The patent uses composite liquid crystal compositions containing multiple components including polymerizable compounds with specific functional groups, spacers with controlled lengths, and liquid crystal hosts, where each component contributes to balancing polymerization speed and electrical stability
2Reliability
If UV radiation intensity is reduced in UV2 step to avoid negative effects, then reliability is improved, but complete polymerization of residual polymerizable compounds is difficult to achieve
Solution Approach 1:
The patent designs polymerizable compounds with optimized molecular structures that enhance UV absorption efficiency and polymerization reactivity, allowing complete polymerization at lower UV intensities, thereby avoiding image sticking while ensuring full conversion of polymerizable compounds
Solution Approach 2:
The patent converts the potential harm of residual polymerizable compounds causing image sticking into a benefit by designing compounds that polymerize completely under controlled conditions, eliminating residues that would otherwise cause display defects
3Loss of substance
If polymerizable compounds are fully polymerized to reduce polymer residue, then image sticking is reduced, but pre-tilt angle stability may be affected
Solution Approach 1:
The patent creates localized polymer networks with specific spatial distributions and density characteristics through controlled polymerization, where the polymer phase separates appropriately to maintain pre-tilt angle while eliminating residues that cause image sticking
Solution Approach 2:
The patent employs composite formulations with carefully balanced components including polymerizable compounds, spacers, and liquid crystal hosts that work together to achieve complete polymerization while preserving pre-tilt angle stability through optimized molecular interactions
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 faster pre-tilt angle formation, reduced polymer residue, improved VHR, and enhanced stability, minimizing display defects and maintaining image quality over time.
Implementation Method 1
the polymerizable compounds contained in the liquid crystal composition are polymerized or crosslinked in situ, usually by UV photopolymerization, which is achieved by exposing the liquid crystal composition to UV radiation
Data Source
AI summary
A liquid crystal composition includes at least one compound represented by formula I and at least one compound represented by formula II. The liquid crystal composition has a relatively large absolute value of dielectric anisotropy, a relatively large K value, a relatively long low-temperature storage time period, a relatively low polymer layer surface roughness, a relatively small pre-tilt angle, a relatively fast speed for forming pre-tilt angle, a relatively low polymer residue, a relatively high VHR and a relatively good pre-tilt angle stability, while maintaining appropriate clearing points, optical anisotropy and rotational viscosity. A liquid crystal display device containing the liquid crystal composition has a relatively wide temperature usage range, relatively good contrast, and relatively good low-temperature mutual solubility. In addition, the production process of PSA-type liquid crystal displays is improved, and at the same time, the problems of “image sticking”, uneven display and “broken bright spots”.