Tin Oxide Coated Glass Substrate with Silicon Oxide Interlayer
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Solution Overview
Problem
Tin oxide-based layers on glass substrates exhibit high haze due to light scattering, which increases with thickness, compromising infrared reflection and optical properties, while existing solutions fail to maintain low emissivity and conductivity with acceptable haze levels.
Innovation Solution
A transparent glass substrate coated with a stack of thin layers, including a titanium oxide-based underlayer and a thick tin oxide-based layer doped with elements like fluorine or antimony, deposited using chemical vapour deposition, achieving low haze and high infrared reflection with optimized thickness and doping for improved conductivity and optical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the thickness of the tin oxide-based layer is increased to improve infrared reflection properties, then the infrared reflection is improved, but the haze increases
Solution Approach 1:
A silicon oxide-based intermediate layer is introduced between the glass substrate and the tin oxide-based layer. This intermediary layer acts as a buffer that reduces light scattering while allowing the tin oxide layer to achieve optimal thickness for infrared reflection. The silicon oxide layer modifies the optical interface properties, enabling high infrared reflection with minimal haze even when the tin oxide layer is thickened.
Solution Approach 2:
The patent employs a composite structure combining silicon oxide and tin oxide materials. The silicon oxide provides optical smoothing and reduced scattering, while the tin oxide delivers high infrared reflection and electrical conductivity. This composite approach allows the system to achieve both low haze and high infrared reflection simultaneously, resolving the contradiction between these two properties.
2Reliability
If the thickness of the tin oxide-based layer is increased to improve electrical conductivity, then the electrical conductivity is improved, but the haze increases
Solution Approach 1:
The silicon oxide-based intermediate layer serves as a mediator that allows the tin oxide layer to be thickened for improved electrical conductivity without proportionally increasing haze. The intermediary layer optimizes the optical interface, enabling the tin oxide layer to achieve desired conductivity through increased thickness while maintaining acceptable optical clarity.
3Reliability
If the tin oxide-based layer is deposited to achieve low emissivity, then the low emissivity is achieved, but the haze increases
Solution Approach 1:
The patent uses a composite material system where silicon oxide and tin oxide work together to achieve low emissivity. The silicon oxide component reduces light scattering and haze, while the tin oxide component provides the necessary infrared reflection for low emissivity. This composite structure enables simultaneous achievement of low emissivity and low haze.
Solution Approach 2:
The silicon oxide-based intermediate layer acts as an intermediary that decouples the relationship between emissivity reduction and haze increase. By providing an optimal optical interface, it allows the tin oxide layer to be thickened for low emissivity while the silicon oxide layer compensates by reducing light scattering, thus maintaining low haze levels.
4Reliability
If a thick tin oxide-based layer is deposited to improve infrared reflection, then the infrared reflection is improved, but the visual appearance deteriorates due to whitish haze
Solution Approach 1:
The silicon oxide-based intermediate layer is introduced as a visual mediator between the glass substrate and the thick tin oxide layer. This intermediary layer optimizes the optical interface properties, allowing the tin oxide layer to achieve the desired infrared reflection while maintaining a clear visual appearance by reducing the whitish haze that would otherwise be visible through the coating.
Solution Approach 2:
The composite structure of silicon oxide and tin oxide materials enables the system to achieve high infrared reflection with acceptable visual appearance. The silicon oxide component provides optical clarity and reduces scattering, while the tin oxide component delivers the necessary infrared reflection, together creating a coating that is both functionally effective and visually acceptable.
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 achieves low haze (<2%) with high infrared reflection (>80%) and low emissivity (<0.12) while maintaining good conductivity and optical properties, ensuring a uniform and visually acceptable appearance.
Implementation Method 1
deposited by chemical vapour deposition
Implementation Method 2
increased reflection of the electromagnetic radiation at wavelengths in the range between 3 and 50 μm
Implementation Method 3
This haze is caused by scattering of the light
Data Source
AI summary
A transparent glass-type substrate coated with a stack of thin layers is described, which comprises at least one titanium oxide-based underlayer and a tin oxide-based main layer, the coated substrate having a very low haze, while also exhibiting a low emissivity or favourable electrical conductivity. A process for the production of a substrate coated with layers deposited by pyrolysis is also described.