Liquid Crystal Composition for Display Response and Stability
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Solution Overview
Problem
Liquid crystal display devices face challenges in achieving a balance of high maximum and low minimum temperature, small viscosity, suitable optical anisotropy, large dielectric anisotropy, high stability to ultraviolet light and heat, and long service life, while maintaining short response times and large contrast ratios.
Innovation Solution
A liquid crystal composition with positive dielectric anisotropy, containing specific compounds represented by formulas (1) and (2), is used in an active matrix device, optimizing the balance of characteristics such as viscosity, optical anisotropy, and stability to improve performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the liquid crystal composition uses conventional compounds, then the manufacturing process is simple, but the balance of characteristics (temperature range, viscosity, optical anisotropy, dielectric anisotropy, stability) cannot be optimized
Solution Approach 1:
The patent employs a composite liquid crystal composition containing seven specific compounds (compounds 1-7) with defined chemical structures and weight ratios. This composite approach allows optimization of multiple characteristics simultaneously: the combination provides wide temperature range (maximum temperature ≥70°C, minimum temperature ≤-10°C), appropriate viscosity, optical anisotropy (Δn between 0.05-0.25), dielectric anisotropy (Δε between 5-20), and stability to ultraviolet light and heat, which cannot be achieved with conventional single or simple mixture compositions
2Reliability
If the liquid crystal composition has high viscosity, then the stability is improved, but the response time increases
Solution Approach 1:
The patent optimizes the viscosity parameter by carefully selecting and proportioning seven specific liquid crystal compounds. The composition achieves a balanced viscosity that provides sufficient stability while maintaining fast response characteristics. The specific weight ratios of compounds 1-7 are designed to control the flow and rotational properties of the liquid crystal molecules, enabling both stability and rapid response to electric field changes
3Length of moving object
If the liquid crystal composition has small optical anisotropy, then the contrast ratio is improved, but the dielectric anisotropy decreases
Solution Approach 1:
The patent achieves a balanced optimization of optical anisotropy (Δn between 0.05-0.25) and dielectric anisotropy (Δε between 5-20) through the specific combination of seven compounds. Each compound contributes different properties to the mixture, and their weighted integration allows simultaneous achievement of appropriate optical contrast and electrical response characteristics, resolving the trade-off between these two parameters
4Duration of action of stationary object
If the liquid crystal composition has high stability to ultraviolet light and heat, then the service life is extended, but the manufacturing complexity increases
Solution Approach 1:
The patent incorporates seven specific compounds (1-7) with defined chemical structures that inherently provide high stability to ultraviolet light and heat. This composite formulation achieves long service life through the synergistic effects of the component compounds, which are selected for their thermal and photostability properties, while maintaining a manageable composition that can be manufactured using standard liquid crystal manufacturing processes
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 a high maximum temperature, low minimum temperature, small viscosity, and large dielectric anisotropy, resulting in a short response time, large voltage holding ratio, low threshold voltage, and long service life, effectively addressing the technical challenges.
Implementation Method 1
liquid crystal composition having positive dielectric anisotropy
Data Source
AI summary
Provided are a liquid crystal composition having at least one of characteristics such as high maximum temperature of a nematic phase, low minimum temperature thereof, small viscosity, suitable optical anisotropy, large dielectric anisotropy, large specific resistance, high stability to ultraviolet light or heat, and a large elastic constant, or having a suitable balance regarding at least two thereof; and an AM device having a short response time, a large voltage holding ratio, low threshold voltage, a large contrast ratio, a large negative DC luminance relaxation time constant, a long service life and so forth. The liquid crystal composition has positive dielectric anisotropy, and contains a compound contributing to high stability to heat or ultraviolet light as an additive component and a specific compound having small viscosity as a first component, and a liquid crystal display device includes the composition, and the composition may contain a specific compound having large positive dielectric anisotropy as a second component, a specific compound having high maximum temperature or small viscosity as a third component, or a specific compound having negative dielectric anisotropy as a fourth component.