Liquid Crystal Composition for Fast Response and Stability
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Solution Overview
Problem
Current liquid crystal materials for TFT-LCDs face challenges in achieving a balance of low viscosity, high optical anisotropy, broad nematic phase temperature range, and stability to electric fields and electromagnetic radiation, while also requiring fast response times and low drive voltage to reduce energy consumption.
Innovation Solution
A liquid crystal composition comprising specific compounds represented by formulas I, II, and III, which provide a low viscosity, high optical anisotropy, and broad nematic phase temperature range, along with high electrical resistivity and anti-ultraviolet properties, is developed, excluding compounds with -CN structures and pyridine or pyrimidine rings to enhance charge holding ratio and resistivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If liquid crystal materials are designed for fast response speed, then response time is reduced, but rotary viscosity γ1 must be lowered which may compromise other performance parameters
Solution Approach 1:
The patent employs composite liquid crystal formulations combining multiple compounds (cyclic carboxylic acid esters, cyclic carbonates, and specific liquid crystal compounds with formulas I-III) to achieve fast response speed while maintaining stable performance. The synergistic combination allows independent optimization of viscosity for speed and other parameters for reliability.
Solution Approach 2:
The patent systematically adjusts molecular parameters including carbon chain lengths (R1-R6 groups with specific carbon atom numbers), ring structures, and functional groups to precisely control rotary viscosity γ1 and other performance parameters, enabling fast response while maintaining overall performance stability.
2Use of energy by moving object
If drive voltage is reduced to lower energy consumption, then power efficiency improves, but achieving low viscosity and fast response becomes more difficult
Solution Approach 1:
The patent uses composite liquid crystal materials with specifically formulated ratios of multiple compounds to achieve low viscosity and fast response characteristics that enable reduced drive voltage operation, while the composite formulation itself manages the material complexity through systematic molecular design.
Solution Approach 2:
The patent introduces compounds with specific local molecular structures (formulas I-III with defined R groups and ring structures) that locally optimize viscosity and response characteristics without compromising overall material stability, enabling energy-efficient operation.
3Loss of time
If cell thickness is reduced to improve response time, then rise time and fall time decrease, but manufacturing precision and uniformity become more challenging
Solution Approach 1:
The patent adjusts liquid crystal material parameters (viscosity, elastic constants, birefringence) to compensate for reduced cell thickness, maintaining fast response performance while providing a margin that accommodates manufacturing variations in cell thickness uniformity.
4Adaptability or versatility
If liquid crystal compounds with broad nematic phase temperature range are selected, then operational temperature range expands, but viscosity and response characteristics may vary across temperatures
Solution Approach 1:
The patent formulates composite liquid crystal compositions combining multiple compounds with complementary temperature-dependent properties, where the composite as a whole maintains stable viscosity and response characteristics across a broad nematic phase temperature range, overcoming the temperature sensitivity of individual components.
Data Source
AI summary
Disclosed is a liquid crystal composition comprising one or more compounds represented by formula I and/or formula II and one or more compounds represented by formula III:wherein the definition of each substituent is given. The composition involved in the present invention has a low viscosity γ1, a high clearing point Tni and a large optical anisotropy Δn, and can realize a rapid response of liquid crystal display.