Phenol Derivative Liquid Crystal for Low Viscosity and Wide Temperature Range
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Solution Overview
Problem
Current liquid crystal display devices face challenges in achieving a balance of chemical and physical stability, low viscosity, suitable optical anisotropy, and wide temperature range, along with low threshold voltage and power consumption, which are not adequately addressed by existing liquid crystal compounds.
Innovation Solution
A phenol derivative compound represented by Formula (1) is developed, which exhibits negatively large dielectric anisotropy, stability to heat and light, and compatibility with other liquid crystal compounds, forming a liquid crystal composition that enhances the performance of liquid crystal display devices by providing a wide temperature range, short response time, and low driving voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If compounds with high clearing point are used to widen temperature range, then upper limit temperature of nematic phase is improved, but viscosity increases
Solution Approach 1:
The patent modifies molecular parameters of liquid crystal compounds by introducing specific substituents (fluorine atoms, cyano groups, and tailored alkyl chains) to adjust the balance between clearing point and viscosity. This allows achieving high clearing point while maintaining low viscosity through optimized molecular structure parameters.
Solution Approach 2:
The patent creates composite liquid crystal compositions by combining multiple compounds with complementary properties. The composition includes compounds with high clearing points combined with compounds having low viscosity characteristics, achieving both goals simultaneously through material composition rather than single compound optimization.
2Power
If compounds with high dielectric anisotropy are used to lower threshold voltage, then driving voltage is improved, but viscosity increases
Solution Approach 1:
The patent changes dielectric parameters of liquid crystal compounds by introducing polar groups (cyano, fluorine substituents) that enhance dielectric anisotropy while controlling molecular size and shape to prevent excessive viscosity increase. This parameter optimization allows low threshold voltage with acceptable viscosity.
Solution Approach 2:
The patent applies local modifications to specific regions of liquid crystal molecules, adding polar substituents at specific positions to enhance dielectric anisotropy locally without requiring the entire molecule to be highly polar, thus avoiding overall viscosity increase.
3Temperature
If compounds with low lower limit temperature are used to widen temperature range, then lower limit temperature of nematic phase is improved, but compatibility with other compounds deteriorates
Solution Approach 1:
The patent adjusts temperature parameters of liquid crystal compounds by modifying molecular structure (introducing flexible alkyl chains, cyclic groups) that lower the lower limit temperature while maintaining compatibility through optimized intermolecular interaction parameters.
Solution Approach 2:
The patent introduces specific functional groups and substituents at particular positions in the molecular structure that locally enhance low-temperature compatibility without compromising overall compositional stability, allowing wide temperature range while maintaining good compatibility.
4Illumination intensity
If compounds with high optical anisotropy are used to improve display quality, then optical anisotropy is improved, but viscosity increases
Solution Approach 1:
The patent optimizes optical parameters by introducing aromatic rings and conjugated structures that enhance optical anisotropy while controlling molecular cross-section and intermolecular spacing to prevent excessive viscosity increase.
Solution Approach 2:
The patent creates composite compositions combining compounds with high optical anisotropy and low viscosity characteristics, achieving superior display quality through compositional balance rather than relying on single compounds with extreme properties.
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 phenol derivative compound improves the performance of liquid crystal display devices by offering a wide usable temperature range, short response time, low power consumption, and large contrast ratio, while maintaining stability and compatibility with other compounds.
Implementation Method 1
a negatively large dielectric anisotropy
Implementation Method 2
the clearing point is a transition temperature from a liquid crystal phase to an isotropic phase
Implementation Method 3
appropriate optical anisotropy
Data Source
AI summary
The invention is to provide such a liquid crystal compound that has general properties required for a liquid crystal compound, stability to heat, light and the like, a small viscosity, a suitable optical anisotropy, a negatively large dielectric anisotropy, a wide temperature range of a nematic phase, and favorable compatibility with other liquid crystal compounds, and a liquid crystal composition containing the compound. The invention provides a compound represented by Formula (1), wherein Ra and Rb are hydrogen or an alkyl having 1 to 20 carbon atoms; ring A1 is 1,4-cyclohexylene, 1,4-phenylene, pyridine-2,5-diyl, pyridazine-3,6-diyl, decahydronaphthalene-2,6-diyl, 1,2,3,4-tetrahydronaphthalene-2,6-diyl, 5,6,7,8-tetrahydronaphthalene-2,6-diyl, or naphthalene-2,6-diyl; Z1 is a single bond or an alkylene having 1 to 4 carbon atoms; Y1 is hydrogen, halogen, —CN, —CF3, —CHF2, —CH2F, —OCF3, —OCHF2, or —OCH2F; and m is 1, 2, or 3.