Polymer-Stabilized Blue Phase Liquid Crystal for Low Haze Switchable Windows
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional switchable liquid crystal windows suffer from high residual haze values, especially at increasing viewing angles, due to mismatched refractive indices and inherent slow electro-motive mechanisms, leading to aesthetic and durability issues.
Innovation Solution
A polymer-stabilized highly chiral liquid crystal arrangement, such as blue phase liquid crystal, is encapsulated in a mesogenic polymer shell, forming a self-assembled three-dimensional photonic crystal that remains electro-optically switchable under a moderate electric field, reducing angular birefringence and haze through the use of chiral dopants and a polymer matrix.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional liquid crystal arrangements are used in switchable windows, then the windows can change light transmission properties in response to an electric field, but the windows exhibit high residual haze values especially at increasing viewing angles
Solution Approach 1:
The patent changes the physical parameters of the liquid crystal system by introducing highly chiral liquid crystal materials with specific helical structures and incorporating chiral dopants. This modifies the refractive index characteristics and birefringence properties of the liquid crystal arrangement, enabling low residual haze (<4%) across wide viewing angles while maintaining electro-optical switchability.
Solution Approach 2:
The patent employs composite material structures including polymer-stabilized highly chiral liquid crystal systems, blue phase liquid crystal compositions, and multi-component liquid crystal mixtures. These composite arrangements combine materials with complementary optical properties to achieve both low residual haze and effective electro-optical switching.
2Ease of operation
If conventional liquid crystal arrangements are used, then electro-optical switching is achieved, but the switching mechanism is inherently slow
Solution Approach 1:
The patent utilizes blue phase liquid crystal materials that exhibit specific phase transition characteristics. The blue phase structure, with its three-dimensional chiral domain organization, enables faster response times compared to conventional nematic liquid crystals while maintaining electro-optical switchability through moderate applied voltages.
Solution Approach 2:
The patent modifies the viscoelastic parameters and molecular mobility of the liquid crystal system by using highly chiral materials and optimized compositions. These parameter changes reduce the inherent slow electro-motive mechanism while preserving the electro-optical switching function.
3Illumination intensity
If conventional liquid crystal arrangements are used, then light transmission can be controlled, but mismatched refractive indices cause high angular birefringence and haze
Solution Approach 1:
The patent systematically adjusts the refractive index parameters of the liquid crystal materials by selecting specific highly chiral liquid crystal compounds and chiral dopants. This optimization achieves better refractive index matching between the liquid crystal phase and surrounding materials, reducing angular birefringence and residual haze while maintaining light transmission control.
4Ease of operation
If switchable windows use conventional liquid crystal materials, then privacy control is achieved, but aesthetic performance deteriorates due to high haze at large viewing angles
Solution Approach 1:
The patent optimizes the optical parameters of the liquid crystal system by using highly chiral materials with specific helical pitch and birefringence characteristics. This enables the window to maintain low residual haze (<4%) and high aesthetic performance across wide viewing angles while preserving the privacy control function through electro-optical switching.
Solution Approach 2:
The patent employs composite liquid crystal formulations including blue phase materials, chiral dopants, and polymer stabilizers that work synergistically to achieve both functional privacy control and superior aesthetic optical performance with minimal residual haze.
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 solution achieves low residual haze (<4%) across a wide range of viewing angles in the transmissive state and maintains good opacity in the non-transmissive state, significantly improving the optical performance and durability of switchable windows.
Implementation Method 1
reduction of angular birefringence of highly chiral LC systems, which advantageously reduces haze in applications such as switchable windows
Implementation Method 2
remains electro-optically switchable under a moderate applied voltage (e.g., electric field)
Implementation Method 3
an anisotropic gel of polymer stabilized highly chiral liquid crystal, for example, blue phase liquid crystal
Data Source
Figure 1(a)~1(b)
Figure 2
Figure 3
AI summary
A switchable window (500) includes an electro-optical layer (510) of or including an anisotropic gel of polymer stabilized highly chiral liquid crystal (50), for example, blue phase liquid crystal, encapsulated in, for example, a mesogenic polymer inclusive shell (10), that forms a self-assembled, three-dimensional photonic crystal that remains electro-optically switchable under a moderate applied voltage (e.g., electric field). The liquid crystal (LC) arrangement may be achieved via a polymer assembled blue phase liquid crystal system having a substantially continuous polymer structure case (60) surrounding well-defined discrete bodies of liquid crystal material (20) arranged in a cellular manner. These assembled structures globally connect to form a matrix. This provides for reduction of angular birefringence of highly chiral LC systems, which advantageously reduces haze in applications such as switchable windows.