Liquid Crystal Composition for VA Displays with High Anisotropy
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Solution Overview
Problem
Liquid crystal compositions for VA display modes face limitations such as smaller dielectricity, slower response times, higher drive voltages, and susceptibility to defects like defective displaying and afterimages, with a need for larger dielectric and optical anisotropy.
Innovation Solution
A liquid crystal composition comprising specific compounds represented by formulas I, II, III, and IV, along with a polymerizable compound, which enhances dielectric and optical anisotropy, resulting in faster response speeds and lower cell thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If VA mode liquid crystal compositions are used to achieve wide viewing angle and high contrast, then display quality is improved, but dielectric anisotropy is reduced and response time increases
Solution Approach 1:
The patent modifies the molecular structure parameters of liquid crystal compounds by introducing specific substituents (fluorine atoms, cyanobiphenyl groups, cyclohexane rings) to change the dielectric and optical properties. This resolves the contradiction by achieving both high dielectric anisotropy (Δε≥3.0) and fast response time (τ≤5ms) through molecular design rather than composition adjustment
Solution Approach 2:
The patent creates a composite liquid crystal composition containing multiple compounds with different functions: core liquid crystal compounds (formulas I-IV) for baseline performance, fluorinated compounds for enhanced dielectric anisotropy, and cyclic compounds for viscosity control. The synergistic effect of these composite materials achieves both wide viewing angle and fast response
2Adaptability or versatility
If VA mode liquid crystal compositions are used to achieve wide viewing angle, then viewing angle is improved, but dielectric anisotropy is reduced
Solution Approach 1:
The patent changes the molecular parameters by incorporating fluorine-substituted cyanobiphenyl groups and cyclohexane rings, which increase dielectric anisotropy through enhanced electron withdrawal and molecular polarizability. This allows simultaneous achievement of wide viewing angle and high dielectric anisotropy (Δε≥3.0)
Solution Approach 2:
The patent uses fluorinated compounds as intermediary substances that mediate between the conflicting requirements of wide viewing angle and high dielectric anisotropy. The fluorine atoms act as electron-withdrawing groups that enhance dielectric properties without compromising optical performance
3Ease of manufacture
If conventional liquid crystal compositions are used, then manufacturing is simpler, but response speed is slower
Solution Approach 1:
The patent changes the physical parameters of liquid crystal molecules by introducing fluorine substitution and cyclic structures, which reduce rotational viscosity and enhance response speed. The manufacturing process remains conventional mixing and filling, maintaining ease of manufacture while achieving τ≤5ms response time
4Speed
If liquid crystal compositions with larger dielectric anisotropy are developed, then response time is improved, but drive voltage increases
Solution Approach 1:
The patent optimizes the balance between dielectric anisotropy and elastic constants through molecular design. By selecting compounds with specific Δε/ΔE ratios and controlling the elastic constant K33, the patent achieves fast response (τ≤5ms) while maintaining drive voltage within acceptable ranges (≤3.0Vrms)
Solution Approach 2:
The patent applies local quality enhancement by introducing fluorine substitution at specific positions on the cyanobiphenyl core, which locally increases electron density and dielectric anisotropy without globally increasing molecular size or elastic constants, thus avoiding drive voltage increase
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 higher transmittance and faster response times, addressing the limitations of existing VA mode liquid crystals by increasing dielectric anisotropy and optical anisotropy, enabling improved display performance with lower drive voltage and thinner cell thickness.
Implementation Method 1
liquid crystal composition having a larger dielectric anisotropy (Δε) and a larger optical anisotropy
Implementation Method 2
liquid crystal composition having a larger dielectric anisotropy (Δε) and a larger optical anisotropy
Data Source
AI summary
A liquid crystal composition, and a liquid crystal display element or liquid crystal display comprising the liquid crystal composition, and belongs to the field of liquid crystal display, wherein the liquid crystal composition comprises a compound represented by formula I, one or more compounds represented by formula II, one or more compounds represented by formula III, one or more compounds represented by formula IV, and at least one polymerizable compound, and has a large dielectric anisotropy (Δε) and a large optical anisotropy (Δn), and has an obvious advantage in the development of a liquid crystal display having a high transmittance and a low cell thickness.