Low-E Glass Stacking With Wet Overcoat for Low Haze
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Solution Overview
Problem
Existing low-emissivity glass technologies face issues such as high surface roughness, poor optical performance, and high preparation costs due to columnar structures formed by chemical vapor deposition and high costs associated with magnetron sputtering.
Innovation Solution
A glass stacking is developed with a low-emissivity layer formed by chemical vapor deposition and an overcoat layer formed by wet coating, using silica sol and/or water glass silicate, to address surface roughness and cost-effectiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If chemical vapor deposition is used to form a low-emissivity layer, then the low-emissivity glass can be prepared with low cost and good market applicability, but the surface of the coating forms a columnar structure resulting in high surface roughness, high diffuse reflection, high haze and high visible light reflectivity
Solution Approach 1:
The patent divides the coating system into two separate layers: a low-emissivity layer formed by chemical vapor deposition and an overcoat layer formed by wet coating. This segmentation allows each layer to perform its specific function independently - the low-emissivity layer provides the thermal performance while the overcoat layer addresses the surface roughness and optical performance issues.
Solution Approach 2:
The overcoat layer acts as an intermediary between the columnar-structured low-emissivity layer and the external environment. It fills in the surface irregularities and provides a smooth outer surface that reduces diffuse reflection and haze, while allowing the underlying low-emissivity layer to maintain its thermal properties.
2Manufacturing precision
If magnetron sputtering technology is used to prepare an anti-reflection coating, then the obtained low-emissivity glass product has a smooth surface and the advantages of low haze and low reflection, but the preparation process is not cost-effective
Solution Approach 1:
The patent uses a wet coating method with silica sol or water glass silicate as a cost-effective alternative to expensive magnetron sputtering technology. The overcoat layer material is inexpensive and can be applied using simple, low-cost processes while still achieving the desired surface smoothness and optical performance.
Solution Approach 2:
The patent changes the deposition method parameter from physical vapor deposition (magnetron sputtering) to wet coating, and changes the material parameter from metal-based anti-reflection coatings to silica-based or water glass-based coatings. These parameter changes maintain the surface smoothness and optical performance benefits while dramatically reducing preparation costs.
3Ease of manufacture
If a low-emissivity layer with columnar structure is formed by chemical vapor deposition, then the preparation cost is low, but the glass structure is difficult for cleaning
Solution Approach 1:
The overcoat layer serves as a protective intermediary between the columnar-structured low-emissivity layer and the environment. It provides a smooth, non-porous surface that prevents dirt and contaminants from adhering to the underlying rough surface, making the glass easy to clean while preserving the cost-effective CVD process for the low-emissivity layer.
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 glass stacking achieves low haze, low visible light reflectivity, bendability, and easy cleaning with reduced preparation costs, enhancing market applicability.
Implementation Method 1
the low-emissivity layer is formed by chemical vapor deposition
Implementation Method 2
the overcoat layer is formed by a coating layer containing a wet coating, and the wet coating comprises a silica sol and/or water glass silicate
Data Source
AI summary
A glass stacking includes a glass substrate; a low-emissivity layer; and an overcoat layer; wherein the low-emissivity layer is between the glass substrate and the overcoat layer; the low-emissivity layer is formed by chemical vapor deposition; the overcoat layer is formed by a coating layer containing a wet coating, and the wet coating includes a silica sol and/or a water glass solution.