Liquid Crystal Composition for Faster IPS and FFS Addressing
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Solution Overview
Problem
Existing liquid-crystal displays, particularly in IPS and FFS modes, face issues such as long addressing times, inadequate resistivity, high operating voltages, and low-temperature stability, which affect their performance and reliability, especially in modern applications requiring high contrast, fast response times, and energy efficiency.
Innovation Solution
Development of liquid-crystalline media comprising specific compounds with positive dielectric anisotropy, which include additives with negative dielectric anisotropy to enhance dielectric constant perpendicular to molecular axes, reducing rotational viscosity and improving elastic constants, thereby enhancing brightness, transmission, and response times while maintaining low-temperature stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If liquid-crystalline media with positive dielectric anisotropy are used in IPS and FFS displays, then the displays can achieve broad viewing angles and good contrast, but the addressing times become excessively long
Solution Approach 1:
The patent modifies the dielectric properties of the liquid-crystalline medium by adding compounds with negative dielectric anisotropy to reduce the overall dielectric anisotropy value. This parameter change allows the liquid crystal molecules to respond faster to applied electric fields, thereby reducing addressing times while maintaining display performance
Solution Approach 2:
The invention creates a composite liquid-crystalline medium by combining compounds with positive dielectric anisotropy (for maintaining display mode characteristics) with compounds having negative dielectric anisotropy (for reducing addressing times). This composite approach balances competing requirements to achieve both fast response and reliable display function
2Speed
If liquid-crystalline media are designed for fast response times, then the addressing speed improves, but the resistivity becomes inadequate
Solution Approach 1:
The patent carefully adjusts the dielectric anisotropy parameter by selecting specific ratios of positive and negative dielectric anisotropy compounds. This optimization allows achieving fast response times through reduced rotational viscosity while simultaneously maintaining adequate resistivity by preserving sufficient dielectric anisotropy for proper electrode control
3Illumination intensity
If the dielectric constant perpendicular to molecular axes is increased to improve brightness and transmission, then the contrast ratio improves, but the rotational viscosity increases causing slower response times
Solution Approach 1:
The patent optimizes the balance between dielectric constant (ε⊥) and rotational viscosity by selecting specific compounds with negative dielectric anisotropy that have favorable viscosity characteristics. The additive compounds are chosen to increase ε⊥ for improved brightness while their molecular structures are selected to minimize the increase in rotational viscosity, thereby maintaining fast response times
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 new liquid-crystalline media provide improved contrast, faster response times, and high-temperature stability, making them suitable for mobile and large-size displays with reduced energy consumption and enhanced reliability.
Implementation Method 1
Liquid-crystalline media having positive dielectric anisotropy
Implementation Method 2
an electric field which is generated substantially perpendicular to the substrates and the liquid-crystal layer
Data Source
AI summary
The present invention relates to liquid-crystalline (LC) media having positive dielectric anisotropy and to liquid-crystal displays (LCDs) containing these media, especially to displays addressed by an active matrix and in particular to LC displays of the TN, PS-TN, STN, TN-TFT, OCB, IPS, PS-IPS, FFS, HB-FFS, XB-FFS, PS-FFS, SA-HB-FFS, SA-XB-FFS, polymer stabilised SA-HB-FFS, polymer stabilised SA-XB-FFS, positive VA or positive PS-VA type.