Fluorovinyl Liquid Crystal Compound for High Clearing Point and Low Viscosity
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Solution Overview
Problem
Current liquid crystal compounds fail to achieve a balance of high stability, high clearing point, low minimum temperature, small viscosity, suitable optical anisotropy, large dielectric anisotropy, and excellent solubility, which are essential for improving the performance of liquid crystal display devices.
Innovation Solution
A liquid crystal compound represented by formula (1) is developed, featuring a fluorovinyl group, halogen or alkyl terminal groups, specific ring structures, and bonding groups, which enhance the compound's physical properties such as clearing point, dielectric anisotropy, and solubility, allowing for a wide temperature range, short response time, and improved device performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional liquid crystal compounds are used, then the device can operate, but the clearing point is insufficiently high and the dielectric anisotropy is insufficiently large
Solution Approach 1:
The patent applies parameter changes by modifying the molecular structure of liquid crystal compounds through introducing fluorovinyl groups and specific ring structures (cyclohexylene, phenylene, pyrimidine, pyridine). These structural parameter changes result in compounds with clearing points above 80°C and large dielectric anisotropy, directly resolving the contradiction between achieving high clearing point and maintaining device performance
Solution Approach 2:
The patent employs composite materials by creating liquid crystal compositions that mix multiple compounds with different physical properties. The composition includes compounds with fluorovinyl groups combined with other liquid crystal compounds, achieving a synergistic effect that simultaneously provides high clearing point, large dielectric anisotropy, and excellent solubility, thus resolving the contradiction between high clearing point and device reliability
2Loss of time
If the viscosity is decreased to shorten response time, then the response time becomes short, but the threshold voltage increases
Solution Approach 1:
The patent applies parameter changes by carefully selecting molecular structures with specific ring combinations and fluorovinyl group positions that achieve an optimal balance between viscosity and dielectric anisotropy. The compounds exhibit small viscosity for fast response while maintaining large dielectric anisotropy for low threshold voltage, resolving the contradiction between response time and energy consumption
3Temperature
If the clearing point is increased to extend temperature range, then the maximum temperature increases, but the solubility in other liquid crystal compounds decreases
Solution Approach 1:
The patent applies local quality by introducing fluorovinyl groups at specific positions on the molecular structure and selecting particular ring structures (cyclohexylene, phenylene, pyrimidine, pyridine) that provide both high clearing point and good solubility. This localized structural optimization allows the compound to achieve clearing points above 80°C while maintaining excellent solubility in other liquid crystal compounds, resolving the contradiction between temperature range and compositional stability
Data Source
AI summary
A liquid crystal compound having a high stability to heat, light and so forth, a high clearing point, a low minimum temperature of a liquid crystal phase, a small viscosity, a suitable optical anisotropy, a large dielectric anisotropy, a suitable elastic constant and an excellent solubility in other liquid crystal compounds, a liquid crystal composition containing the compound, and a liquid crystal display device including the composition. The compound is represented by formula (1):wherein, for example, R1 is fluorine or alkyl having 1 to 10 carbons; ring A1 and ring A2 are 1,4-phenylene, or 1,4-phenylene in which at least one of hydrogen is replaced by fluorine; Z1, Z2 and Z3 are a single bond; L1 and L2 are hydrogen or fluorine; X1 is fluorine or —CF3; and m is 1, and n is 0.