Liquid Crystal Composition for Fast Response and Wide Temperature Range
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Solution Overview
Problem
Liquid crystal display devices face challenges in achieving a balance of high maximum temperature, low minimum temperature, small viscosity, suitable optical anisotropy, large dielectric anisotropy, small frequency dependence, large specific resistance, high stability to ultraviolet light, and high stability to heat while maintaining a short response time and long service life.
Innovation Solution
A liquid crystal composition with positive dielectric anisotropy, containing specific compounds represented by formulas (1) and (2), is interposed between transparent substrates with an alignment layer and a polarizing plate, along with a transparent electrode, to enhance the display device's performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the maximum temperature of the nematic phase is increased to extend the usable temperature range, then the temperature range is widened, but the viscosity increases and response time lengthens
Solution Approach 1:
The patent applies parameter changes by carefully selecting and combining liquid crystal compounds with specific molecular structures and physical properties. The composition includes compounds with balanced viscosity-temperature characteristics and appropriate elastic constants, allowing the system to maintain optimal response times across an extended temperature range by adjusting the compositional parameters rather than relying on a single high-temperature compound
Solution Approach 2:
The patent uses composite materials by formulating a multi-component liquid crystal composition where different compounds serve complementary functions. The mixture includes compounds with varying viscosity, elastic constant, and temperature range properties, creating a synergistic effect that achieves both wide temperature stability and fast response that individual compounds cannot provide alone
2Speed
If the viscosity is decreased to shorten the response time, then the response time is reduced, but the elastic constant decreases and contrast ratio is reduced
Solution Approach 1:
The patent applies parameter changes by optimizing the compositional ratios of liquid crystal compounds to achieve a specific viscosity-elastic constant balance. The formulation includes compounds with high elastic constants combined with those having appropriate viscosity characteristics, and adjusts their proportions to maintain the elastic constant above 10 pN while keeping viscosity below 50 mPa·s, thereby achieving both fast response and high contrast
3Use of energy by moving object
If the dielectric anisotropy is increased to reduce threshold voltage and power consumption, then the threshold voltage and power consumption are reduced, but the frequency dependence increases and response time worsens at low temperature
Solution Approach 1:
The patent applies parameter changes by selecting liquid crystal compounds with specific dielectric anisotropy values and combining them in optimized ratios. The composition includes compounds with high dielectric anisotropy to reduce threshold voltage, but balances this with compounds that have favorable frequency dependence characteristics, adjusting the compositional parameters to maintain stable performance across different driving frequencies and temperatures
4Reliability
If the specific resistance is increased to improve voltage holding ratio and contrast ratio, then the voltage holding ratio and contrast ratio are improved, but the manufacturing complexity increases
Solution Approach 1:
The patent uses composite materials by formulating a liquid crystal composition with multiple compounds that collectively provide high specific resistance. The mixture includes compounds with complementary electrical properties, and the synergistic effect of the combination achieves the desired voltage holding ratio and contrast ratio without requiring complex manufacturing processes or additional functional layers
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 suitable balance of characteristics, resulting in a liquid crystal display device with a short response time, large voltage holding ratio, high contrast ratio, and long service life, suitable for various applications including liquid crystal projectors and televisions.
Implementation Method 1
the liquid crystal composition has positive dielectric anisotropy
Data Source
AI summary
Shown is a liquid crystal composition satisfying at least one of characteristics such as high maximum temperature, low minimum temperature, small viscosity, suitable optical anisotropy, large dielectric anisotropy and small frequency dependence, or has a suitable balance regarding at least two of the characteristics, and an AM device including the composition. The liquid crystal composition contains a specific compound having large positive dielectric anisotropy as a first component, and a specific compound having small viscosity as a second component, and may contain a specific compound having high maximum temperature or small viscosity as a third component, a specific compound having positive dielectric anisotropy as a fourth component or a specific compound having negative dielectric anisotropy as a fifth component.