Variable Transmission Coating for Architectural Glass Color Uniformity
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Solution Overview
Problem
Non-light-emitting variable transmission devices in architectural glass exhibit significant color differences when in different transmission states, making them appear dissimilar even when constructed identically, which is aesthetically undesirable.
Innovation Solution
A coating is applied to reduce color differences by balancing luminous transmission and color variation, comprising layers with specific refractive indices and thicknesses, including a high refractive index layer and a barrier layer, to minimize the appearance of color differences while maintaining acceptable light transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a non-light-emitting variable transmission device is used in architectural glass, then the transmission state can be varied to control light, but significant color differences appear between different transmission states making windows appear dissimilar
Solution Approach 1:
The patent applies a coating with specific optical properties (refractive index between 1.8-2.2) that modifies the color appearance of the variable transmission device. The coating is designed to minimize color differences between high and low transmission states by controlling reflectance and absorbance characteristics, thereby maintaining appearance uniformity while preserving transmission state variation capability
Solution Approach 2:
The patent uses a composite coating structure comprising multiple layers with different materials and optical properties. This includes a first coating layer with specific refractive index and thickness, and optionally a second coating layer, creating a composite optical system that balances color stability across different transmission states while maintaining the variable transmission function
2Shape
If a coating is applied to reduce color differences, then appearance uniformity is improved, but luminous transmission may be reduced
Solution Approach 1:
The patent optimizes specific parameters of the coating including refractive index (1.8-2.2), thickness (50-200 nm), and layer structure to achieve a balance between color stability and light transmission. By carefully controlling these parameters, the coating minimizes color differences while maintaining acceptable luminous transmission levels for architectural applications
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 coating achieves a significant reduction in color difference (ΔE) between high and low transmission states, ensuring a more uniform appearance of windows with non-light-emitting variable transmission devices, while maintaining sufficient luminous transmission, typically between 20% and 60%.
Implementation Method 1
A non-light-emitting variable transmission device and a coating are provided. The coating can include a first layer having a refractive index of at least 2.2
Data Source
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AI summary
An article can include a non-light-emitting, variable transmission device and a coating disposed between the non-light-emitting, variable transmission device and an ambient outside the article. In an embodiment, the article has a DE of at most 6.5. In another embodiment, the coating includes a plurality of layers including a first layer having a refractive index of at least 2.2 and a thickness of at least 10 nm. The coating can be used to help reduce color differences seen when the non-light-transmitting, variable transmission device is taken to different transmission states. In a particular embodiment, the coating can provide a good balance between color difference and luminous transmission.