Blue Coated Glass With Multi-Layer IR Reflectors
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Solution Overview
Problem
Existing solar control coatings struggle to achieve a blue glass side reflective coloration while maintaining low solar factor (SF) and solar heat gain coefficient (SHGC) values, often requiring significant adjustments that result in undesirable interference effects or high reflectivity.
Innovation Solution
Incorporating two or more infrared (IR) reflecting layers, such as NbZr and NbZrNx, between dielectric layers with specific thickness parameters to achieve blue glass side reflective coloration, low glass side visible reflectivity, and acceptable film side coloration, without using metallic IR reflecting layers like Ag or Au, thereby controlling color and thermal stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the bottom dielectric thickness is significantly increased to achieve bluish green coloration, then blue coloration is improved, but undesirable interference effects occur
Solution Approach 1:
The patent divides the single IR-reflecting layer into multiple separate IR-reflecting layers (first IR-reflecting layer and second IR-reflecting layer) separated by dielectric layers. This segmentation allows independent optimization of each layer's thickness and position, achieving blue coloration through constructive interference while avoiding undesirable interference effects by carefully controlling the spacing and thickness of each segment.
Solution Approach 2:
The patent transitions from a single-layer approach to a multi-layer stack architecture, adding the dimension of layer stacking. By arranging multiple IR-reflecting layers at different positions within the coating stack, the patent achieves blue coloration through controlled optical interference in the vertical dimension while maintaining low solar factor values.
2Loss of energy
If low solar factor (SF) values are achieved, then solar heat gain control is improved, but coloration is sacrificed
Solution Approach 1:
The patent assigns different local properties to different layers: the first IR-reflecting layer is optimized for infrared reflection to control solar heat gain, while the second IR-reflecting layer and surrounding dielectric layers are optimized for optical interference to produce blue coloration. This local quality differentiation allows simultaneous achievement of low SF values and desirable blue coloration.
Solution Approach 2:
The patent uses a composite multi-layer structure combining different materials (dielectric layers with specific refractive indices, metallic or metalloid IR-reflecting layers) to achieve both low solar factor values and blue coloration. The composite structure allows independent optimization of thermal and optical properties through material selection and layer design.
3Illumination intensity
If glass side visible reflectivity is reduced, then visibility is improved, but blue coloration control becomes more difficult
Solution Approach 1:
The patent optimizes multiple parameters including the thickness of each layer, the refractive index of dielectric materials, and the position of IR-reflecting layers within the stack. By carefully adjusting these parameters, the patent achieves blue coloration with controlled glass side visible reflectivity, balancing visibility and coloration requirements through precise parameter optimization.
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 achieves desirable blue glass side reflective coloration combined with low SF and SHGC values, providing improved color control and thermal stability, allowing for cooler room temperatures in warm climates without additional metal layers.
Implementation Method 1
Incorporating two or more infrared (IR) reflecting layers, such as NbZr and NbZrNx, between dielectric layers with specific thickness parameters
Implementation Method 2
if bluish green is desired the approach is to significantly increase the bottom dielectric thickness which unfortunately results in undesirable interference effects in that particular coating
Implementation Method 3
achieve blue glass side reflective coloration, low glass side visible reflectivity, and acceptable film side coloration
Data Source
AI summary
There are provided coated articles that include two or more infrared (IR) reflecting layers (e.g., of or including NbZr, Nb, NiCr, NiCrMo, and/or a nitride thereof) sandwiched between at least dielectric layers, and/or a method of making the same. The coating may be designed so that the coated articles realize blue glass side reflective coloration in combination with a low glass side visible reflectance, acceptable film side coloration, and low solar factor (SF) and/or a low solar heat gain coefficient (SHGC). Such coated articles may be used in the context of monolithic windows, insulating glass (IG) window units, laminated windows, and/or other suitable applications, and may optionally be heat treated (e.g., thermally tempered) in certain instances.