Heat-Treatable UV Blocking Coating for Glass Substrates
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Solution Overview
Problem
Current heat-resistant UV blocking coatings for glass substrates face challenges such as undesired optical effects, high reflectivity, and the risk of micro-cracks during heat treatment, making them unsuitable for commercial applications, especially in window applications where cost-effectiveness and minimal optical defects are crucial.
Innovation Solution
A method involving a UV blocking coating comprising a mixture of titanium, cerium, and silicon oxides with a refractive index between 1.55 and 1.85, combined with an organic polymer top coating that pyrolyzes during heat treatment, forming a thicker, crack-free coating that effectively blocks UV and IR radiation without significant optical interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If ceria-titania-silica coatings are used to enhance UV blocking ability, then UV blocking performance is improved, but rainbow-like colours and high reflectivity occur due to large refractive index difference
Solution Approach 1:
The patent applies parameter changes by precisely controlling the refractive index of the ceria-titania-silica coating through adjusting the titania content and coating thickness. The refractive index is maintained between 1.60-1.80 (optimal 1.65-1.75), and thickness is controlled at 50-150 nm (optimal 75-125 nm), which resolves the contradiction between UV blocking performance and optical quality by optimizing these physical parameters.
Solution Approach 2:
The patent uses composite materials by combining ceria, titania, and silica in specific proportions to create a coating with balanced properties. The composite composition (CeO2: 10-30%, TiO2: 10-30%, SiO2: 60-80%) achieves both effective UV blocking and minimized optical interference effects, resolving the contradiction between functionality and aesthetic quality.
2Object-generated harmful factors
If coating thickness is increased to minimize interference effects, then optical quality is improved, but micro cracks develop during heat treatment
Solution Approach 1:
The patent applies parameter changes by optimizing coating thickness to 50-150 nm (optimal 75-125 nm), which is thick enough to minimize interference effects but thin enough to remain crack-free after heat treatment. This precise parameter control resolves the contradiction between optical quality and structural reliability.
Solution Approach 2:
The patent applies local quality by ensuring uniform composition and refractive index throughout the coating layer through controlled sol-gel processing. This uniformity prevents stress concentration and crack formation during heat treatment, allowing the coating to achieve sufficient thickness for optical quality without developing defects.
3Object-generated harmful factors
If silica content is increased to reduce refractive index, then reflectivity and interference effects are minimized, but coating thickness must be increased to maintain UV blocking
Solution Approach 1:
The patent applies parameter changes by optimizing the refractive index to 1.60-1.80 (optimal 1.65-1.75) through balanced composition control, which allows the coating to achieve both low reflectivity and adequate UV blocking at a moderate thickness of 50-150 nm. This resolves the contradiction between optical quality and UV blocking performance without requiring excessive thickness.
Solution Approach 2:
The patent uses composite materials with optimized ratios of ceria, titania, and silica to achieve a refractive index that balances UV blocking ability and optical quality. The composite composition (SiO2: 60-80%, CeO2: 10-30%, TiO2: 10-30%) provides both low reflectivity and sufficient UV blocking at moderate thickness, resolving the contradiction between minimizing interference effects and maintaining UV blocking.
4Object-generated harmful factors
If multi-layer oxide coatings are applied to suppress optical defects, then optical quality is improved, but manufacturing complexity and cost increase
Solution Approach 1:
The patent applies the extraction principle by removing the need for multi-layer structures and achieving optical defect suppression through a single-layer coating with controlled composition and refractive index. This simplifies the manufacturing process while maintaining optical quality, resolving the contradiction between optical performance and manufacturing complexity.
Solution Approach 2:
The patent applies multi-functionality by designing a single-layer ceria-titania-silica coating that simultaneously provides UV blocking, minimized interference effects, and crack resistance. This universal coating eliminates the need for multiple specialized layers, resolving the contradiction between optical quality and manufacturing simplicity.
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 provides a cost-effective, heat-treatable UV blocking coating that remains substantially crack-free and minimizes undesired optical effects, effectively blocking UV and IR radiation while maintaining structural integrity and operational functionality.
Implementation Method 1
an organic polymer top coating that pyrolyzes during heat treatment
Implementation Method 2
effectively blocking UV and IR radiation
Implementation Method 3
The rainbow-like colours may be caused by interference of light caused, at least in part, by a large difference between refractive indices of substrate and coating
Data Source
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AI summary
A composite oxide coating is provided on a substrate over an optional infrared (IR) blocking multi-layer coating (e.g., low-E coating), where the composite oxide coating efficiently blocks ultraviolet (UV) radiation. An organic polymer top coating may be provided over the composite oxide, where the organic polymer may be formed by exposing a photomonomer and/or photopolymer to radiation (e.g., UV radiation). The coated glass substrate may be heat and/or crack resistant and may be subjected to a high temperature heat treatment step. The coated article may be effective at blocking IR and/or UV radiation in applications such as window applications. The UV blocking coating may include ceria, titania, and silica as UV blocker(s) in certain example embodiment of this invention.