Selective Glazing with Three-Layer Silver Stack
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Solution Overview
Problem
Existing selective glazings with three functional metallic layers face challenges in achieving high selectivity, excellent color neutrality, and low optical sensitivity, particularly due to thickness variations in the stack layers, which affect uniform production and quality across large substrates.
Innovation Solution
A transparent substrate coated with a stack comprising three silver-based layers of increasing thickness, paired with similar optical thicknesses for the dielectric coatings closest to the substrate and small thickness blocking layers, to achieve high selectivity, excellent color neutrality, and low optical sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If three functional metallic layers are used to achieve high selectivity and solar control, then solar factor is reduced and light transmission is maintained, but the stack becomes complex and sensitive to thickness variations
Solution Approach 1:
The patent changes the parameters of the metallic layers by using three silver-based layers with specifically controlled thickness ratios (Ag2/Ag1 ≥ 1.05 and Ag3/Ag2 ≥ 1.05) instead of conventional metallic layers. This parameter optimization reduces sensitivity to thickness variations while maintaining high selectivity (S > 1.8) and solar control performance.
Solution Approach 2:
The patent creates a composite stack structure combining three silver-based metallic layers with dielectric coatings and blocking layers. This composite approach integrates multiple functional layers with complementary properties to achieve high selectivity, color neutrality, and reduced optical sensitivity simultaneously.
2Productivity
If sputtering deposition is used to produce stacks on large substrates, then production capability is achieved, but thickness variations of 5-10% occur perpendicular to the running direction
Solution Approach 1:
The patent incorporates blocking layers with specific thickness ranges (0.1-1.8 nm for certain functional layers) that act as cushioning elements to compensate for thickness variations. These layers are designed beforehand to tolerate and mask the 5-10% thickness variations inherent in sputtering deposition on large substrates.
Solution Approach 2:
The patent modifies the thickness parameters of individual layers to create a more tolerant stack design. By optimizing the thickness ratios between successive silver layers and using blocking layers with controlled thickness, the system becomes less sensitive to deposition variations while maintaining production efficiency.
3Reliability
If conventional stacks target blue-green colors in external reflection, then solar control is achieved, but aesthetic neutrality is compromised
Solution Approach 1:
The patent deliberately changes the color characteristics of the stack by designing three silver-based metallic layers with increasing thickness that produce neutral colors (a* between -5 and +5, b* between -5 and +5) in external reflection, internal reflection, and transmission. This replaces the conventional blue-green color target with aesthetically neutral coloration while maintaining solar control performance.
Solution Approach 2:
The patent uses a composite structure of silver-based layers combined with dielectric coatings to achieve both solar control and color neutrality. The interaction between the metallic and dielectric layers creates optical interference effects that produce neutral colors while maintaining high selectivity and low solar factor.
4Productivity
If thickness variations of 5-10% occur in stack layers, then production variations are introduced, but colorimetric characteristics become sensitive to these variations
Solution Approach 1:
The patent changes the design parameters to create a stack with reduced optical sensitivity. By using three silver-based layers with specific thickness ratios and incorporating blocking layers, the system's colorimetric characteristics become less sensitive to thickness variations, achieving ΔCi < 5 for layers with thickness variations up to 5%.
Solution Approach 2:
The patent creates a robust template design that can be replicated across different production sites. The standardized three-layer silver structure with defined thickness ratios and blocking layers serves as a reproducible model that maintains consistent colorimetric properties despite normal production variations.
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 results in a material with high selectivity, neutral colors in transmission and reflection, and reduced optical sensitivity, enabling uniform production and improved quality across the substrate width, while maintaining high light transmission and low solar factor.
Implementation Method 1
a stack of thin layers successively comprising, from the substrate, an alternation of three functional silver-based metallic layers... and of four dielectric coatings
Implementation Method 2
which can influence solar radiation and/or infrared radiation
Implementation Method 3
These stacks are generally obtained by a sequence of depositions carried out by sputtering, optionally assisted by a magnetic field
Data Source
AI summary
A material includes a transparent substrate coated with a stack of thin layers including an alternation of three functional silver-based metallic layers. This material makes it possible to obtain a multiple glazing having good thermal performance results, in particular a selectivity greater than 2, excellent color neutrality and low optical sensitivity.