Low-E Coating Absorber Layer for Visible Reflectance Reduction
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Solution Overview
Problem
Conventional coated articles for insulating glass (IG) window units face challenges in achieving a combination of desirable visible transmission, color, low reflectance, low emissivity, and low sheet resistance, particularly in reducing visible reflectance while maintaining effective IR blockage.
Innovation Solution
Incorporating a color and reflectivity-adjusting absorber layer between dielectric layers in the low-E coating, allowing for tunable color and reflectivity properties, and optimizing the thickness of other layers to reduce glass side reflectance and achieve desired aesthetic and solar performance characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If thick IR reflecting layers (e.g., silver based layers) are used to block IR radiation, then IR blockage is improved, but visible reflectance increases
Solution Approach 1:
The coating is divided into multiple functional layers: a first absorber layer (e.g., NiCr, NbZr) for color control and visible reflectance reduction, a dielectric layer for optical interference, and a second absorber layer for additional IR reflection. This segmentation allows each layer to optimize its specific function without compromising others, achieving both IR blockage and low visible reflectance
Solution Approach 2:
The patent employs composite material structures combining different materials with complementary properties: metallic absorber layers (NiCr, NbZr, stainless steel) for IR reflection and color control, dielectric materials (silicon nitride, silicon oxide) for optical interference and low visible reflectance. This composite approach enables simultaneous achievement of IR blockage and aesthetic properties
2Adaptability or versatility
If absorber layers are added to control color and reflectivity, then color control is improved, but device complexity increases
Solution Approach 1:
The patent controls color and reflectivity by adjusting parameters such as layer thickness (e.g., first absorber layer 10-150 Å, dielectric layer 50-500 Å, second absorber layer 10-150 Å) and material composition (e.g., stainless steel with 10-20% chromium). These parameter variations enable tuning of optical properties without fundamentally changing the coating structure, maintaining manufacturing simplicity while achieving versatile color control
Data Source
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AI summary
A coated article is provided, having a coating supported by a glass substrate where the coating includes at least one color and/or reflectivity-adjusting absorber layer. The absorber layer(s) allows color tuning, and reduces the glass side reflection of the coated article and/or allows sheet resistance of the coating to be reduced without degrading glass side reflection. In certain example embodiments the absorber layer is provided between first and second dielectric layers which may be of substantially the same material and/or composition. In certain example embodiments, the coated article is capable of achieving desirable transmission, together with desired color, low reflectivity, and low selectivity, when having only one infrared (IR) reflecting layer of silver and/or gold. Coated articles according to certain example embodiments of this invention may be used in the context of insulating glass (IG) window units, monolithic windows, or the like.