Polyfluorinated Additives for Liquid Crystal Mixtures
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Solution Overview
Problem
Conventional liquid crystal displays face challenges with high specific resistance, temperature stability, low threshold voltages, and the occurrence of 'ODF mura' due to inadequate flow behavior and wetting properties of liquid crystal mixtures, leading to issues with viewing angle dependence and image quality.
Innovation Solution
A liquid crystalline medium containing specific polyfluorinated additives with formula I, which improves wetting and flow properties while maintaining optimized electro-optical and chemical properties, reducing the occurrence of 'ODF mura' and enhancing temperature stability and resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional liquid crystal mixtures are used to achieve high specific resistance, then temperature stability improves, but wetting properties and flow behavior deteriorate, leading to ODF mura defects
Solution Approach 1:
The patent modifies the chemical composition parameters of the liquid crystal mixture by introducing polyfluorinated compounds with specific molecular structures (Formula I and II). These compounds contain fluorinated alkyl groups and aromatic rings that alter the mixture's surface tension and flow characteristics while maintaining high specific resistance and temperature stability.
Solution Approach 2:
The patent creates a composite liquid crystal mixture combining conventional liquid crystal compounds with specially designed polyfluorinated additives. This composite approach allows the mixture to simultaneously achieve high specific resistance from the base materials and improved wetting/flow properties from the fluorinated components, resolving the contradiction between reliability and manufacturing precision.
2Manufacturing precision
If liquid crystal mixtures with improved flow behavior are used, then ODF mura reduces, but specific resistance and temperature stability worsen
Solution Approach 1:
The patent carefully controls the concentration of polyfluorinated compounds in the mixture (typically 0.1-10 wt%) to optimize flow behavior without compromising specific resistance. The fluorinated compounds' molecular parameters are adjusted to ensure they improve wetting properties while maintaining the electrical properties required for high reliability.
Solution Approach 2:
The polyfluorinated compounds locally modify the liquid crystal mixture's properties at the substrate interface where wetting occurs, while the bulk mixture retains its high specific resistance and temperature stability. This localized quality enhancement allows improved flow behavior without sacrificing overall reliability.
3Manufacturing precision
If polyfluorinated additives are added to improve wetting properties, then flow behavior improves, but mixture complexity increases
Solution Approach 1:
The patent uses a limited number of polyfluorinated compound types with systematically varied parameters (alkyl chain length, aromatic ring substitutions) to achieve the desired wetting properties. This parameter-based approach allows optimization of flow behavior while keeping the mixture composition relatively simple and manageable.
Solution Approach 2:
The polyfluorinated compounds serve multiple functions simultaneously: they improve wetting properties, enhance flow behavior, and maintain compatibility with the base liquid crystal mixture. This multi-functionality reduces the need for multiple separate additives, thereby limiting the increase in mixture complexity.
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 use of polyfluorinated additives in liquid crystalline media enhances the wetting and flow properties, reduces 'ODF mura', and achieves high specific resistance and temperature stability, improving the overall performance and image quality of liquid crystal displays.
Implementation Method 1
improves wetting and flow properties
Implementation Method 2
enhances the wetting and flow properties
Implementation Method 3
the dielectric constant ε of the liquid crystalline medium is therefore different for the two orientations
Implementation Method 4
the longitudinal axis of the molecules aligns so that the larger of the two dielectric constants becomes effective
Implementation Method 5
The strength of the interaction with the electric field depends on the difference between these two constants
Implementation Method 6
Dielectric anisotropy is influenced by both the polarizability of the molecule and its permanent dipole moments
Implementation Method 7
Its purpose is to use surface forces to align the longitudinal axes of adjacent crystalline molecules in a preferred direction
Data Source
AI summary
The invention relates to polyfluorinated additives for use as components in liquid crystal mixtures, liquid crystal mixtures containing these compounds, and liquid crystal displays on the basis of such mixtures.