Reflective Liquid Crystal Composition Single Driving Voltage
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Solution Overview
Problem
Cholesteric liquid crystal materials require different driving voltages for different reflective wavelengths, making it necessary to provide multiple driving voltages for full-color displays, which complicates the driving circuit design and increases power consumption.
Innovation Solution
A reflective liquid crystal material formulation comprising specific ratios of liquid crystal components with varying dielectric anisotropy, allowing for a single driving voltage to operate liquid crystal components with different reflective wavelengths, thereby reducing the driving voltage difference between them.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the concentration of chiral agent is increased to achieve desired reflective wavelengths, then the reflective wavelength can be modified, but the driving voltage increases in direct ratio
Solution Approach 1:
The patent changes the chemical composition parameters of the liquid crystal host mixture to achieve different reflective wavelengths without proportionally increasing chiral agent concentration. By adjusting the host mixture composition (using different ratios of liquid crystal compounds), the patent modifies the reflective properties while controlling the driving voltage, thus resolving the direct ratio relationship between chiral agent concentration and driving voltage
Solution Approach 2:
The patent uses composite liquid crystal host mixtures consisting of multiple liquid crystal compounds in specific ratios. This composite approach allows tuning of reflective wavelengths through composition adjustments rather than solely relying on chiral agent concentration, thereby decoupling the relationship between wavelength modification and driving voltage increase
2Reliability
If different driving voltages are provided for RGB cholesteric liquid crystal materials, then each color can be driven at its optimal voltage, but the driving circuit design becomes complicated
Solution Approach 1:
The patent develops a universal liquid crystal composition system where a single driving voltage can effectively drive multiple color (RGB) cholesteric liquid crystal materials. By formulating the host mixture and chiral agent concentrations appropriately, the system achieves similar driving voltages across different color materials, allowing one driving circuit to control all color elements without requiring separate voltage control circuits for each color
3Reliability
If different driving voltages are applied for different color liquid crystal materials, then optimal performance for each color is achieved, but power consumption increases
Solution Approach 1:
The patent merges the driving voltage requirements of different color liquid crystal materials into a unified voltage level. By carefully formulating each color material's composition (host mixture and chiral agent ratio), the patent ensures that red, green, and blue cholesteric liquid crystal materials can all be driven at approximately the same voltage, thereby reducing the overall power consumption compared to using separate optimized voltages for each color
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 formulation enables a single driving voltage to be used across liquid crystal components with different reflective colors, simplifying the driving circuit design and reducing power consumption while maintaining stable bistable states.
Implementation Method 1
The cholesteric liquid crystal is composed of optically active chiral agent and nematic liquid crystal, with helical pitch controlled by the ratio therebetween... Cholesteric liquid crystals can reflect the surrounding light... the reflectance of liquid crystal composition can be modified depending on desired reflective wavelengths
Implementation Method 2
Cholesteric liquid crystals, otherwise called chiral nematic liquid crystals, are generally prepared by mixing a twisted nematic liquid crystal with a chiral agent (chiral dopant). Due to the chiral agent, cholesteric liquid crystals exhibit higher twisting angular than that of twisted nematic liquid crystals... The relationship between helical pitch P and amount of optically active chiral agent is: P=1/(HTP·C)
Implementation Method 3
Cholesteric liquid crystals have several states, including a homeotropic state in which the direction of the liquid crystal molecules is approximately parallel to the substrate, and two stable states of a planar state and a focal conic state with no voltage applied. Cholesteric liquid crystals exhibit a bistable state characteristic, and the two stable states are stable in the absence of an electric field
Data Source
AI summary
The invention discloses a reflective liquid crystal material formulation, wherein a liquid crystal component of high dielectric anisotropy is employed to lower the driving voltage. By modulating the addition ratio of the high dielectric anisotropy components, reflective liquid crystal compositions of different reflective colors can be driven by a single driving voltage. The invention also provides a reflective bistable display using the above formulation.