Nematic Liquid Crystal Composition for Fast VA Mode Response
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Solution Overview
Problem
Liquid crystal compositions for VA mode displays require low viscosity, fast response, and wide temperature stability with negative dielectric anisotropy, but existing compositions fail to achieve satisfactory solubility at low temperatures and optimal viscosity for fast response.
Innovation Solution
A liquid crystal composition combining specific compounds represented by general formulas (I-1), (II-A), and (III-A) with controlled mass percentages, refractive index anisotropy, and viscosity, along with optional additives like polymerizable compounds and stabilizers, to achieve the desired properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If liquid crystal compositions are designed to have low viscosity for fast response, then response speed is improved, but solubility at low temperatures deteriorates
Solution Approach 1:
The patent employs composite liquid crystal compositions combining multiple compounds with complementary properties. Specifically, it uses compounds with fluorine-substituted terphenyl structures combined with other liquid crystal molecules to achieve both low viscosity for fast response and adequate solubility at low temperatures through synergistic effects of the composite system.
Solution Approach 2:
The patent systematically adjusts molecular parameters including fluorine substitution patterns, molecular weight, and structural configurations to optimize the balance between viscosity and solubility. By changing these molecular parameters, the composition achieves low viscosity while maintaining stable solubility across a wide temperature range.
2Use of energy by moving object
If liquid crystal compositions are designed to have large absolute value of negative Δε for VA mode, then driving voltage is reduced, but viscosity increases
Solution Approach 1:
The patent uses composite compositions where compounds with large negative Δε are combined with other liquid crystal molecules that have lower viscosity. This composite approach allows the system to achieve the required negative dielectric anisotropy for VA mode while the overall viscosity remains acceptable for fast response performance.
Solution Approach 2:
The patent applies local quality by having different components in the composition serve different functions: some compounds provide the necessary negative Δε while others primarily contribute to low viscosity. This functional differentiation within the composition allows simultaneous optimization of both parameters.
3Stability of the object's composition
If liquid crystal compositions are designed for wide temperature range operation, then operational stability is improved, but response speed deteriorates
Solution Approach 1:
The patent employs composite compositions where the combined properties of multiple compounds achieve both wide temperature stability and low viscosity. The synergistic interaction between different liquid crystal molecules in the composite system allows maintaining nematic phase stability across wide temperature ranges while keeping viscosity low for fast response.
Solution Approach 2:
The patent adjusts molecular parameters including chain length, aromatic ring structures, and substituent types to optimize the temperature-response trade-off. By carefully selecting and adjusting these parameters, the composition achieves wide operating temperature range while maintaining fast response characteristics.
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 low viscosity, stable solubility at low temperatures, and fast response, enhancing the practicality and display quality of VA mode and PSVA mode liquid crystal display devices.
Implementation Method 1
a nematic liquid crystal composition useful as a liquid crystal display material and exhibiting a negative value of dielectric anisotropy (Δε)
Implementation Method 2
in view of setting of Δn × d which is the product of refractive index anisotropy (Δn) and a cell gap (d)
Data Source
AI summary
A liquid crystal composition of the present invention is used for a liquid crystal display device of an active matrix driving method, which requires fast response. The liquid crystal composition has negative dielectric anisotropy and a large absolute value thereof, and low viscosity. The liquid crystal composition is chemically stable to heat, light, water, and the like, and is suitable as a liquid crystal composition capable of low-voltage driving and practicable and having high reliability. A liquid crystal display device using the liquid crystal composition can be preferably used for a liquid crystal display device of a VA mode, a PASV mode, a PSA mode, or the like.