Heat-Treatable Solar Control Coating to Reduce Red Haze
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Solution Overview
Problem
Solar control coatings experience undesirable haze formation due to changes in optical properties and morphology upon heating, which affects absorption and color stability.
Innovation Solution
A coated article comprising a substrate with a base layer of tin oxide, a metallic layer, and a top layer, where the base layer includes a first film of tin oxide in direct contact with the substrate and a second film covering the entire first film, reducing scattering center formation and red haze when heated to temperatures above 1,185°F.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a solar control coating with a metallic layer is heated to high temperatures, then the coating provides thermal processing capability, but scattering centers form in the metallic layer causing haze and color changes
Solution Approach 1:
A base layer comprising tin oxide and zinc oxide is introduced as an intermediary between the substrate and the metallic layer. This base layer acts as a protective barrier that prevents scattering center formation in the metallic layer during high-temperature heating, thereby maintaining optical property stability while enabling thermal processing
Solution Approach 2:
The base layer is formed as a composite material comprising tin oxide and zinc oxide. This composite structure provides enhanced stability and protection against scattering center formation compared to single-material coatings, allowing the metallic layer to maintain its optical properties during high-temperature processing
2Ease of manufacture
If the base layer contains only tin oxide, then the deposition process is simpler, but scattering center formation and red haze occur during heating
Solution Approach 1:
The base layer is formulated as a composite of tin oxide and zinc oxide. This composite material provides superior resistance to scattering center formation and red haze during heating compared to tin oxide alone, while maintaining a relatively simple dual-material deposition process
Solution Approach 2:
The composition parameters of the base layer are optimized by incorporating both tin oxide and zinc oxide in specific proportions. This parameter adjustment enhances the base layer's ability to prevent scattering center formation and red haze, addressing the harmful effects while maintaining manufacturing feasibility
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 effectively reduces scattering center formation and red haze in the metallic layer, maintaining the absorption and color of the coated article before and after heating.
Implementation Method 1
a base layer having a first film of tin oxide to prevent diffusion of alkali metal ions, alkaline earth metal ions, and metal ions, such as sodium ions and zinc ions, from a glass substrate into a medium (e.g., a coating such as, a solar control coating), or from a medium (e.g., a coating such as, a solar control coating) into a glass substrate
Implementation Method 2
Metal layers deposited below a critical thickness (referred to herein as 'subcritical layers') form discontinuous regions, islands or interconnected islands with uncovered regions between the islands rather than a continuous layer. These discontinuous layers absorb electromagnetic radiation through an effect known as surface Plasmon resonance
Implementation Method 3
The coated article is heated to a temperature of greater than or equal to 1,185° F. The coated article has reduced scattering center formation in the metallic layer after heating to a temperature of greater than or equal to 1,185° F
Data Source
AI summary
A coated article includes a substrate with a first surface and a second surface and a functional coating applied over the surface. The functional coating includes a base layer over at least a portion of the substrate; a metallic layer over at least a portion of the base layer; and a top layer over at least a portion of the metallic layer. The base layer includes a first film of tin oxide over at least a portion of the substrate and a second film covering the entire portion of the first film. Methods of making a coated article, reducing scattering center formation, and reducing red haze formation are also provided.