Bimesogenic Compounds for Low-Voltage Flexoelectric Displays
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Solution Overview
Problem
Current flexoelectric liquid crystal displays face challenges such as high driving voltage requirements, narrow phase ranges of chiral nematic materials, irreversible switching properties, and poor contrast due to non-uniform orientation and high voltage needs, which are not compatible with current LCD driving schemes.
Innovation Solution
The development of bimesogenic compounds with specific structural features, including terminal alkyl groups and lateral dipoles, which improve alignment and maintain flexoelectric properties, leading to low melting points, broad chiral nematic phases, high elastic constants, and high flexoelectric coefficients when used in chiral nematic liquid crystal mixtures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If conventional chiral nematic materials are used in flexoelectric displays, then the display can achieve fast response times, but the driving voltage requirement becomes excessively high and the phase range becomes narrow
Solution Approach 1:
The patent modifies the molecular structure of chiral nematic materials by introducing specific bimesogenic compounds with terminal alkyl groups and lateral dipoles. These structural parameter changes result in materials that maintain fast response times while reducing the driving voltage requirement and expanding the phase range, directly resolving the technical contradiction between response speed and energy consumption.
2Speed
If conventional chiral nematic materials are used, then fast response can be achieved, but the switching becomes irreversible and contrast deteriorates
Solution Approach 1:
The patent introduces bimesogenic compounds with specific molecular parameters (terminal alkyl groups and lateral dipoles) that fundamentally change the material properties. These parameter changes enable reversible switching behavior while maintaining fast response times and improving contrast, thereby resolving the contradiction between response speed and switching reliability.
3Device complexity
If conventional liquid crystal materials are used, then the display structure can be simple, but the alignment becomes non-uniform and contrast is poor
Solution Approach 1:
The patent changes the molecular parameters of the liquid crystal materials by incorporating bimesogenic compounds with terminal alkyl groups and lateral dipoles. These parameter changes improve the alignment uniformity and contrast ratio while maintaining a simple display structure, thus resolving the contradiction between device simplicity and manufacturing precision.
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
These bimesogenic compounds enable high switching angles, fast response times, and good uniform alignment at low temperatures, with improved contrast and reduced voltage requirements, making them suitable for flexoelectric displays with enhanced performance.
Implementation Method 1
a chiral substance which is mixed with a nematic material induces a helical twist transforming the material into a chiral nematic material, which is equivalent to a cholesteric material
Implementation Method 2
The flexoelectric effect is characterized by fast response times typically ranging from 6 μs to 100 μs. It further features excellent grey scale capability. The field induces a splay bend structure in the director which is accommodated by a tilt in the optical axis.
Data Source
AI summary
The invention relates to bimesogenic compounds of formula (I) wherein R11, R12, MG11, MG12, X11, X12 and Sp1 have the meaning given in claim 1, to the use of bimesogenic compounds of formula (I) in liquid crystal media and particular to flexoelectric liquid crystal devices comprising a liquid crystal medium according to the present invention.