Twisted Nematic Liquid Crystal Multilayer Laminates for Infrared Reflection
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Solution Overview
Problem
Current glass laminates struggle to effectively reduce infrared radiation transmission while maintaining visible light transmission and safety characteristics, particularly in architectural and automotive applications, where energy efficiency and threat resistance are increasingly demanded.
Innovation Solution
A multilayer laminate article comprising nonmicellar twisted nematic liquid crystal layers with cholesteric infrared-reflecting properties, paired with polymeric sheets and potentially half-wave plates, to reflect infrared radiation while allowing visible light transmission, enhancing energy efficiency and safety features.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional glass laminates use thick polymeric interlayers to provide safety characteristics, then impact resistance and penetration resistance are improved, but infrared radiation transmission reduction capability deteriorates
Solution Approach 1:
The patent combines conventional polymeric interlayers with liquid crystal layers to create a composite laminate structure. The polymeric layer provides mechanical strength and safety characteristics, while the liquid crystal layer provides infrared radiation reflection. This composite approach allows both functions to coexist without compromising either property.
Solution Approach 2:
The patent changes the optical parameters of the laminate by introducing liquid crystal materials with specific helical structures that reflect infrared radiation. By controlling the pitch and handedness of the liquid crystal helix, the laminate can selectively reflect infrared wavelengths while maintaining visibility in the visible spectrum, thus reducing heat transmission without sacrificing safety properties.
2Loss of energy
If glass laminates add layers to reduce infrared radiation transmission, then energy efficiency is improved, but device complexity increases
Solution Approach 1:
The liquid crystal layer serves multiple functions simultaneously: it reflects infrared radiation to reduce heat transmission, maintains optical clarity for visibility, and can be integrated with existing safety glass laminates. This multi-functionality reduces the need for separate infrared-blocking layers, thereby limiting the increase in overall complexity.
Solution Approach 2:
The liquid crystal layer acts as an intermediary between the glass layers and the external environment, selectively interacting with different wavelengths of radiation. It mediates the transmission of visible light while blocking infrared radiation, providing a elegant solution that addresses energy efficiency without requiring complex multi-layer configurations.
3Object-affected harmful factors
If micellar liquid crystal materials are used in glazings to control solar radiation, then infrared reflection is improved, but haze increases
Solution Approach 1:
The patent employs nonmicellar liquid crystal materials that maintain local molecular order without forming scattered micellar structures. This allows the liquid crystal to reflect infrared radiation through its helical structure while maintaining optical clarity in the visible spectrum. The local quality of molecular arrangement provides infrared reflection without the haze associated with micellar formations.
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 effectively reduces energy requirements by reflecting undesired infrared radiation while maintaining high visible light transmission and providing enhanced safety and resistance characteristics, making it suitable for various applications including automotive and construction uses.
Implementation Method 1
nonmicellar twisted nematic liquid crystal having cholesteric infrared-reflecting properties
Implementation Method 2
reflecting infrared radiation
Implementation Method 3
infrared radiation
Implementation Method 4
bonded together with an interlayer of a polymeric film or sheet
Data Source
AI summary
Provided are multilayer laminates having one or more layers comprising twisted nematic liquid crystals and one or more layers of a polymeric sheet comprising a polymer with a modulus of 20,000 psi (138 MPa) or less. The twisted nematic liquid crystal layers reflect infrared radiation. Thus, the multilayer laminates are useful to reduce the transmission of infrared energy. For example, in some embodiments the multilayer laminates are useful as windows to reduce energy consumption necessary to cool the interior of a structure such as an automobile or building. Preferably, the multilayer laminates retain the beneficial properties of safety glass. The multilayer laminates may include additional layers such as infrared absorbing layers, half wave plates, and the like, to minimize the transmission of infrared energy. The multilayer laminates may also include further additional layers such as polymeric films, polymeric sheets, rigid sheets, and the like.