Low-E Coating Absorber Layer for Visible Reflectance Control
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Solution Overview
Problem
Conventional insulating glass window units face challenges in achieving a combination of desirable visible transmission, color, low reflectance, low emissivity, and low sheet resistance, as thick IR reflecting layers often increase visible reflectance, making it difficult to balance these properties effectively.
Innovation Solution
Incorporating a color and/or reflectivity-adjusting absorber layer between dielectric layers in the low-E coating, along with manipulating the thicknesses of other layers, allows for tunable color properties and reduced glass side reflectance, enabling a combination of low visible reflectance and emissivity while maintaining acceptable visible transmission and solar protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If thick IR reflecting layers are used to block infrared radiation, then low emissivity and solar protection are improved, but visible reflectance increases
Solution Approach 1:
The coating is divided into multiple functional layers including dielectric layers, absorber layers, and IR reflecting layers. This segmentation allows each layer to perform its specific function independently, enabling thick IR reflecting layers to block infrared radiation while other layers control visible reflectance and provide coloration.
Solution Approach 2:
Different layers are assigned different optical properties: dielectric layers provide low visible reflectance, absorber layers provide coloration and additional IR blocking, and IR reflecting layers provide thermal reflection. This local quality assignment allows the system to achieve low emissivity without compromising visible reflectance control.
2Loss of energy
If thick IR reflecting layers are used to achieve low emissivity, then solar protection is improved, but color appearance and visible transmission are compromised
Solution Approach 1:
Absorber layers are positioned between dielectric layers to provide coloration and control visible transmission independently of the IR reflecting layers. This allows the system to achieve both solar protection and desirable color appearance with controlled visible transmission.
Solution Approach 2:
The coating combines multiple materials with different optical properties: dielectric materials for low visible reflectance, metallic absorber materials for coloration and IR absorption, and IR reflecting materials for thermal reflection. This composite structure enables simultaneous optimization of solar protection, color appearance, and visible transmission.
3Loss of energy
If multiple functional layers are added to achieve low-E properties, then low emissivity and solar protection are improved, but coating complexity increases
Solution Approach 1:
The coating is segmented into distinct functional layers (dielectric layers, absorber layers, IR reflecting layers) that can be deposited using standard vacuum coating processes. This segmentation maintains manufacturing simplicity while achieving complex low-E functionality through the coordinated action of individual layers.
Data Source
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.