TN Liquid Crystal Composition for Fast Response and Wide Viewing Angle
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Solution Overview
Problem
Liquid crystal displays (LCDs) face challenges in achieving a wide viewing angle, enhanced contrast ratio, and high response speed, as adjustments to liquid crystal molecule properties to improve response speed often compromise these other factors.
Innovation Solution
A liquid crystal display with a liquid crystal layer containing liquid crystal molecules having specific dielectric anisotropy, splay elastic constant, and bend elastic constant values, along with a composition including specific polar compounds, is used to maintain a wide viewing angle and high contrast ratio while enhancing response speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If liquid crystal molecule properties are adjusted to improve response speed, then response speed is improved, but viewing angle and contrast ratio are reduced
Solution Approach 1:
The patent applies parameter changes by precisely controlling the dielectric anisotropy (Δε) within 4.5 to 5.7, splay elastic constant (K11) at 14 pN or less, and bend elastic constant (K33) at 12 pN or greater. These specific parameter ranges enable the liquid crystal molecules to achieve fast response speed while maintaining wide viewing angle and high contrast ratio, resolving the technical contradiction between response speed and viewing angle adaptability
2Speed
If liquid crystal molecule properties are adjusted to improve response speed, then response speed is improved, but contrast ratio is reduced
Solution Approach 1:
The patent resolves the contradiction between response speed and contrast ratio by implementing specific parameter changes: dielectric anisotropy (Δε) controlled within 4.5 to 5.7, splay elastic constant (K11) at 14 pN or less, and bend elastic constant (K33) at 12 pN or greater. These parameter settings enable the liquid crystal composition to achieve both high response speed and enhanced contrast ratio simultaneously
3Speed
If dielectric anisotropy is increased to enhance response speed, then response speed is improved, but elastic constants become unbalanced
Solution Approach 1:
The patent addresses the balance between dielectric anisotropy and elastic constants by implementing coordinated parameter changes: dielectric anisotropy (Δε) within 4.5 to 5.7, splay elastic constant (K11) at 14 pN or less, and bend elastic constant (K33) at 12 pN or greater. This coordinated parameter optimization ensures that increasing dielectric anisotropy for faster response does not disrupt the elastic constant balance, maintaining stable liquid crystal composition
Solution Approach 2:
The patent employs composite materials by formulating a liquid crystal composition containing multiple components including cyanobiphenyl compounds, esters, and other liquid crystal materials. This composite approach allows simultaneous optimization of dielectric anisotropy and elastic constants, achieving balanced performance for response speed and compositional stability
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 solution allows for improved response speed without degrading the viewing angle and contrast ratio, as demonstrated by specific elastic constant and dielectric anisotropy ranges that optimize the alignment and properties of liquid crystal molecules.
Implementation Method 1
liquid crystal molecules having positive dielectric anisotropy... the liquid crystal molecules have a dielectric anisotropy (Δ∈) in a range of 4.5 to 5.7
Implementation Method 2
a splay elastic constant (K11) of 14 pN or less, and a bend elastic constant (K33) of 12 pN or greater
Data Source
AI summary
A twisted nematic (TN) mode liquid crystal display is provided. The liquid crystal display includes first and second display panels facing each other to create an electric field therebetween, and a liquid crystal layer disposed between the first and second display panels. The liquid crystal layer contains liquid crystal molecules having positive dielectric anisotropy, and the liquid crystal layer has a structure in which long axes of the liquid crystal molecules are aligned spirally from the first display panel to the second display panel when no electric field is created in the liquid crystal layer. The liquid crystal molecules have a dielectric anisotropy (Δ∈) in a range of 4.5 to 5.7, a splay elastic constant (K11) of 14 pN or less, and a bend elastic constant (K33) of 12 pN or greater.