Variable Scattering Liquid Crystal Device with Polymeric Network
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Solution Overview
Problem
Conventional electrically controllable liquid crystal devices with smectic mesophase lack reversible switching capabilities, limiting their ability to achieve multiple stable scattering states and color variations under an electric field.
Innovation Solution
A device with a polymeric network and two-dimensional topological defects, comprising a stack of layers with liquid crystals, dichroic dyes, and anchoring layers, allowing for the formation of multiple stable scattering and colored states by aligning liquid crystals between nematic and smectic mesophases, and controlling the orientation with an electric field.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If liquid crystals of smectic mesophase are used, then the device can achieve scattering states, but reversible switching capabilities are lacking
Solution Approach 1:
The patent changes the mesophase parameter from pure smectic to a mixture of nematic and smectic phases. This parameter change enables the liquid crystals to exhibit both scattering properties (from smectic phase) and reversible switching capabilities (from nematic phase), resolving the contradiction between reliability and adaptability
Solution Approach 2:
The patent creates a composite liquid crystal system by mixing nematic and smectic liquid crystals. This composite approach combines the advantages of both phases: nematic phase provides reversible switching while smectic phase provides scattering states, thereby achieving both multiple stable scattering states and reversible switching capabilities
2Adaptability or versatility
If liquid crystals are aligned between nematic and smectic mesophases, then multiple stable scattering and colored states can be achieved, but the device structure becomes more complex
Solution Approach 1:
The patent employs self-assembling polymeric networks and anchoring layers that automatically organize the liquid crystal molecules into desired configurations. This self-service mechanism reduces the need for complex external control systems, achieving multiple stable states while managing device complexity through self-organization
Solution Approach 2:
The patent utilizes phase transitions between nematic and smectic mesophases to achieve multiple stable scattering and colored states. By controlling the phase transition through electric field application, the device can switch between different states without requiring complex mechanical structures, thereby managing complexity while achieving versatility
3Adaptability or versatility
If dichroic dyes are added to liquid crystals, then color variations can be achieved, but the manufacturing precision requirements increase
Solution Approach 1:
The patent optimizes the concentration parameter of dichroic dyes within the liquid crystal mixture to achieve desired color variations while maintaining manufacturability. By carefully controlling the dye concentration within specific ranges, the patent balances color versatility with manufacturing precision requirements
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
Enables reversible switching between multiple stable scattering and colored states, including transparent and scattering states, with rapid transitions and adjustable haze and color changes in response to voltage, enhancing electro-optical properties.
Implementation Method 1
by application of an electric field
Implementation Method 2
liquid crystals, in particular preferably thermotropic and/or lyotropic
Implementation Method 3
electrically controllable device having variable scattering
Implementation Method 4
at least one dichroic dye (in particular in the dissolved state, in particular in liquid crystals)
Implementation Method 5
polymers forming a (three-dimensional) polymeric network, the liquid crystals being (physically) stabilized by the polymeric network
Data Source
AI summary
A device having variable scattering by liquid crystals includes a stack with a first electrode, an electroactive layer with liquid crystals being stabilized by the polymeric network, and a second electrode. The material exhibits, from a temperature referred to as T1, a mesophase referred to as P. At a temperature T′ greater than or equal to T1, the stack is capable of exhibiting at least three stable and reversible scattering states in the visible range and a variable color.