Liquid Crystal Composition for Balanced Dielectric and Thermal Properties
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Solution Overview
Problem
Current liquid crystal compositions for display devices face challenges in achieving a balance of high maximum temperature, low minimum temperature, small viscosity, suitable optical anisotropy, large negative dielectric anisotropy, large specific resistance, high stability to ultraviolet light, and high stability to heat, which affects the devices' performance in terms of response time, voltage holding ratio, contrast ratio, and service life.
Innovation Solution
A liquid crystal composition is developed that includes specific compounds with negative dielectric anisotropy, optimized for a range of characteristics by mixing compounds represented by certain formulas, with additives such as polymerizable compounds to enhance alignment and stability, tailored for use in various operating modes like IPS, VA, and FFS modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the maximum temperature of the nematic phase is increased, then the usable temperature range is extended, but the viscosity may increase causing longer response time
Solution Approach 1:
The patent modifies molecular parameters by introducing specific terminal groups (cyclohexyl, fluoroalkyl) and core structures to compounds, which simultaneously increases the maximum nematic phase temperature while controlling viscosity through optimized molecular weight and structure, thus extending usable temperature range without sacrificing response time
Solution Approach 2:
The patent creates a composite liquid crystal composition by mixing multiple compounds with different molecular structures (cyclohexyl-containing compounds, fluoroalkyl-containing compounds, and other liquid crystal compounds) in specific ratios, achieving a balance between high maximum temperature and low viscosity for fast response
2Speed
If the viscosity is decreased to shorten response time, then the response time is improved, but the stability to heat and ultraviolet light may be reduced
Solution Approach 1:
The patent optimizes molecular parameters by introducing stable terminal groups (cyclohexyl, fluoroalkyl) and appropriate molecular weights that achieve low viscosity for fast response while the stable chemical structures provide inherent resistance to heat and ultraviolet light degradation
Solution Approach 2:
The patent applies different functional groups at specific positions in the molecular structure - cyclohexyl and fluoroalkyl groups at terminal positions for stability, while the core structure maintains low viscosity, creating local functional zones that collectively achieve both fast response and high stability
3Use of energy by moving object
If the dielectric anisotropy is increased to reduce threshold voltage, then the electric power consumption is reduced, but the optical anisotropy may be affected causing contrast ratio to decrease
Solution Approach 1:
The patent carefully adjusts molecular parameters including terminal groups (cyclohexyl, fluoroalkyl) and core structures to achieve a balanced state where dielectric anisotropy is sufficiently high for low threshold voltage and power consumption, while optical anisotropy is maintained at appropriate levels for good contrast ratio
Solution Approach 2:
The patent optimizes the balance between dielectric and optical anisotropy by selecting specific molecular structures and mixing ratios that achieve low threshold voltage for energy efficiency while maintaining adequate contrast ratio through controlled optical properties
4Illumination intensity
If the specific resistance is increased to improve voltage holding ratio, then the contrast ratio is improved, but the response time may be affected
Solution Approach 1:
The patent optimizes molecular parameters such as molecular weight, structure, and terminal groups to achieve a balanced specific resistance that provides high voltage holding ratio for good contrast ratio while maintaining adequate ion mobility for acceptable response time
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 balance of desired characteristics, resulting in a liquid crystal display device with improved response time, voltage holding ratio, low threshold voltage, high contrast ratio, and extended service life, suitable for applications in liquid crystal projectors and televisions.
Implementation Method 1
A liquid crystal composition which has a nematic phase and negative dielectric anisotropy
Implementation Method 2
a liquid crystal composition containing a polymer is used. First, a composition to which a small amount of a polymerizable compound is added is injected into the device. Next, the composition is irradiated with ultraviolet light while voltage is applied between substrates of the device. The polymerizable compound is polymerized to form a network structure of the polymer in the composition.
Data Source
AI summary
Provided are a liquid crystal composition satisfying at least one of characteristics such as high maximum temperature, low minimum temperature, small viscosity, suitable optical anisotropy, large negative dielectric anisotropy, large specific resistance, high stability to ultraviolet light and high stability to heat, or has a suitable balance regarding at least two of the characteristics; and an AM device having characteristics such as a short response time, a large voltage holding ratio, low threshold voltage, a large contrast ratio and a long service life. The liquid crystal composition may contain a specific compound having large negative dielectric anisotropy as a first component, a specific compound having high maximum temperature as a second component, a specific compound having negative dielectric anisotropy as a third component, or a specific compound having a polymerizable group as an additive component.