Substoichiometric ZnSnO Intermediate Layer for Low-E Glazing
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Solution Overview
Problem
Existing glazing technologies require high power and long treatment times to achieve low emissivity and high light transmission, which is not satisfactory for all applications.
Innovation Solution
A stack of thin layers with a single metallic functional layer and two antireflection coatings, where one antireflection coating includes a mixed oxide of zinc and sub-stoichiometric tin, allowing for lower oxygen supply and faster processing without high-temperature heat treatment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If an absorbent intermediate layer is used in the thin film stack, then the absorption during treatment increases making the treatment short and effective, but the layer must be fully oxidized which requires high processing power and long treatment time
Solution Approach 1:
The patent changes the chemical composition parameters of the intermediate layer by incorporating zinc and tin oxides in specific sub-stoichiometric ratios (0.1 ≤ x/y ≤ 2.4 with 0.75(2x + y) ≤ z ≤ 0.95(2x + y) for SnxZnymOz). This compositional parameter change enables the layer to provide sufficient absorption for effective treatment while requiring less oxygen for oxidation, thereby reducing both processing power and treatment time compared to conventional absorbent layers
Solution Approach 2:
The patent uses a composite intermediate layer made from multiple metal oxides (zinc oxide and tin oxide in sub-stoichiometric ratios) rather than a single material. This composite structure provides optimized absorption properties that enable effective treatment with reduced processing requirements, resolving the contradiction between treatment effectiveness and processing power/time
2Productivity
If a substoichiometric mixed oxide of zinc and tin is used in the intermediate layer, then the oxygen supply required is reduced and processing speed increases, but the layer must maintain specific compositional ratios to achieve the desired effect
Solution Approach 1:
The patent defines specific parameter ranges for the intermediate layer composition (0.1 ≤ x/y ≤ 2.4 and 0.75(2x + y) ≤ z ≤ 0.95(2x + y) for SnxZnymOz) that balance the competing requirements. These parameter specifications enable the layer to achieve both high processing speed through reduced oxygen demand and sufficient absorption effectiveness, while providing clear manufacturing targets for compositional control
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 reduces the power required for treatment by a factor of 1.5 to 3 and increases processing speed by 1.2 to 2.5, achieving low emissivity and high light transmission without subjecting the substrate to high-temperature processing.
Implementation Method 1
the use of an absorbent intermediate layer increases the stack's absorption during the treatment, making it short but effective
Implementation Method 2
the implementation of a treatment of the complete thin film stack using a source producing radiation, and in particular infrared radiation
Data Source
Figure 1~2
AI summary
The invention relates to a substrate (10) coated on one face (11) with a thin-film multilayer (14) having reflection properties in the infra red and/or in solar radiation comprising a single metallic functional layer (140), in particular based on silver or on a metal alloy containing silver, and two antireflection coatings (120, 160), said coatings each comprising at least one dielectric layer (122, 164), said functional layer (140) being positioned between the two antireflection coatings (120, 160), characterized in that at least one of said antireflection coatings (120, 160) comprises an intermediate layer comprising a zinc tin oxide SnxZnyOz with a ratio of 0.1 ≤ x/y ≤ 2.4, with 0.75(2x + y) ≤ z ≤ 0.95(2x + y) and having a physical thickness of between 2 nm and 25 nm, or even between 2 nm and 12 nm.