Liquid Crystal Composition for High Transmittance and UV Stability
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Solution Overview
Problem
Current liquid crystal compositions for LCDs face challenges in achieving a balance between high voltage holding ratio, UV stability, thermal stability, and maximum optical transmittance while being environmentally friendly, with existing materials often using chlorine-containing compounds and exhibiting short service life and low contrast.
Innovation Solution
A liquid crystal composition is developed using saturated alkyl neutral monomers, avoiding chlorine-containing compounds, and optimizing the ratios of specific compounds to enhance dielectric anisotropy, optical anisotropy, and clearing point, thereby improving voltage holding ratio, UV stability, and temperature reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If chlorine-containing compounds are used in liquid crystal composition, then dielectric anisotropy and voltage holding ratio can be improved, but environmental friendliness deteriorates
Solution Approach 1:
The patent changes the chemical composition parameters by replacing chlorine-containing compounds with fluorinated compounds and cyanobiphenyl derivatives. Specifically, it uses compounds with formula (I) containing CF3 groups, formula (II) containing F atoms, and formula (III) cyanobiphenyl derivatives, achieving high voltage holding ratio without chlorine-containing harmful substances
Solution Approach 2:
The patent creates a composite liquid crystal composition by combining multiple types of compounds in specific ratios: 10-40 wt% of formula (I) compounds, 10-40 wt% of formula (II) compounds, 5-30 wt% of formula (III) compounds, and 10-40 wt% of formula (IV) compounds. This composite approach achieves synergistic effects for high voltage holding ratio and environmental friendliness
2Illumination intensity
If maximum optical transmittance is increased for better display brightness, then display contrast is improved, but UV stability deteriorates
Solution Approach 1:
The patent changes the molecular structure parameters by introducing fluorinated groups (CF3, F atoms) and cyanobiphenyl structures that simultaneously enhance optical transmittance through improved molecular alignment and provide UV stability through aromatic ring structures that resist UV degradation
Solution Approach 2:
The patent uses formula (IV) compounds as intermediary substances that mediate between optical performance and stability requirements. These compounds with specific mesogenic structures provide both high optical transmittance and UV stability, acting as a bridge between the two conflicting requirements
3Use of energy by moving object
If dielectric anisotropy is increased to reduce power consumption, then voltage holding ratio is improved, but response time deteriorates
Solution Approach 1:
The patent changes the dielectric and viscosity parameters by selecting compounds with optimal molecular structures. Formula (I) and (II) fluorinated compounds provide high dielectric anisotropy for low power consumption, while formula (III) cyanobiphenyl and formula (IV) compounds are selected with appropriate viscosity characteristics to maintain fast response time
Solution Approach 2:
The patent creates a composite composition that balances dielectric anisotropy and viscosity. By combining 10-40 wt% high dielectric anisotropy formula (I) and (II) compounds with 5-30 wt% formula (III) and 10-40 wt% formula (IV) compounds, the composition achieves both low power consumption and acceptable response time through synergistic effects
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 voltage holding ratio, better UV stability, and high temperature reliability with increased maximum absolute transmittance, while being environmentally friendly, suitable for transmissive LCDs, and energy-efficient.
Implementation Method 1
A liquid crystal composition having a large absolute value of dielectric anisotropy can reduce a base voltage value of an LCD device
Implementation Method 2
an element operating in an ECB or VA mode uses a negative dielectric anisotropic liquid crystal
Implementation Method 3
A liquid crystal composition having a large absolute value of dielectric anisotropy can reduce a base voltage value of an LCD device, reduce a drive voltage, and thus reduce electric power consumption
Implementation Method 4
A liquid crystal composition having low viscosity can increase the response speed of an LCD device
Data Source
AI summary
Provided is a liquid crystal composition, comprising: 1-30% of one or more compounds of general formula I; 1-50% of one or more compounds of general formula II; 1-20% of one or more compounds of general formula III; 20-70% of one or more compounds of general formula IV; and 1-30% of one or more compounds of general formula V. The liquid crystal composition has properties such as a large maximum absolute transmittance, a high voltage holding ratio, better anti-UV properties, and high temperature reliability, and has a suitable optical anisotropy, a suitable dielectric anisotropy, and a relatively high clearing point, and is environmentally friendly. The liquid crystal composition is suitable for use in a liquid crystal display device, especially a transmissive liquid crystal display element, enabling the liquid crystal display device to have properties such as a high maximum absolute transmittance, a high voltage holding ratio, good anti-UV properties and high temperature reliability, and to be energy-saving and environmentally-friendly.