Liquid Crystal Composition with Bimesogenic Compounds for Dimming
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Solution Overview
Problem
Existing light modulating devices using negative liquid crystals have a narrow light transmittance modulation range between transparent and dark states, lack privacy protection, and are limited to adjusting transmittance only.
Innovation Solution
A liquid crystal composition comprising negative liquid crystals and bimesogenic compounds with specific structural features, which increases optical anisotropy and introduces light scattering in the dark state, broadening the transmittance tuning range and providing privacy protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional negative liquid crystal compositions are used, then the device achieves transparent state with good light transmittance, but the light transmittance modulation range between transparent and dark states is narrow (only about 30%)
Solution Approach 1:
The patent uses a composite liquid crystal composition comprising negative liquid crystal molecules combined with specific bimesogenic compounds (formula I) having two mesogenic groups. This composite material structure enables simultaneous achievement of high light transmittance in transparent state and sufficient light scattering/darkening in dark state, expanding the modulation range beyond 30% to over 70% while providing privacy protection capability
Solution Approach 2:
The patent modifies the optical parameters of the liquid crystal composition by introducing bimesogenic compounds that change the elastic constant and molecular arrangement uniformity. This parameter change enables the composition to achieve both high transmittance in transparent state and strong light scattering in dark state, resolving the contradiction between modulation range and privacy protection
2Illumination intensity
If the light transmittance tuning range is increased, then the device achieves better privacy protection, but the device complexity increases
Solution Approach 1:
The patent achieves enhanced dark state transmittance reduction (improved privacy protection) by changing the optical parameters of the liquid crystal composition through the addition of bimesogenic compounds. This parameter change in the material composition itself achieves the desired functionality without requiring complex device structures or additional components
Solution Approach 2:
The patent uses molecular-level copying of the bimesogenic compound structure (formula I) into the liquid crystal composition to achieve the desired optical properties. By incorporating these specific molecular structures, the composition achieves enhanced privacy protection functionality without adding physical complexity to the device structure
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 significantly reduces minimum dark state transmittance and increases haze, enhancing the light modulating device's functionality and application scope by broadening the transmittance tuning range and providing privacy protection.
Implementation Method 1
A negative liquid crystal refers to a liquid crystal material whose perpendicular dielectric constant is greater than the parallel dielectric constant, and the liquid crystal molecules are driven to a state that is perpendicular to the electric field when an electric field is applied
Implementation Method 2
Bimesogenic compounds refer to liquid crystal compounds containing two mesogenic groups. Due to their special structure, they can adjust the elastic constant in a nematic liquid crystal mixture, which changes the uniformity of the molecular plane arrangement of the liquid crystal composition
Implementation Method 3
it can serve as a light modulation layer to regulate the transmittance by applying a voltage to the liquid crystal molecules... the light transmittance tuning range between the transparent and dark states is only about 30%
Data Source
AI summary
A liquid crystal composition includes a component A composed of one or more liquid crystals with negative dielectric anisotropy and a component B composed of one or more compounds selected from a general formula I, where the optical anisotropy of the liquid crystal composition is larger than 0.14. The elastic coefficient of a liquid crystal system is adjusted by introducing a bi-mesogenic compound into a negative liquid crystal or a negative liquid crystal mixture. When the liquid crystal composition is used for the dimming device, the minimum light transmittance of the dimming device in the dark state can be significantly reduced, the adjustment range of the light transmittance in the light state and the dark state can be expanded, and the haze in the dark state can be increased, thereby broadening the use range.R1-MG1-X-MG2-R2 I