UV-Treated Low-E Coating for Window Glass
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Solution Overview
Problem
Sputter-deposited silver layers in low-E coatings have poor quality, and traditional heat treatment methods are inefficient and can damage glass substrates, while existing IR irradiation methods are ineffective due to reflection or absorption issues.
Innovation Solution
Exposing the low-E coating to intense ultraviolet (UV) radiation to selectively heat the contact/seed layer, which transfers heat to the silver layer, improving its conductivity and optical properties without damaging the glass substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional heat treatment methods are used to improve silver layer quality, then the electrical and optical properties of the silver layer are improved, but the glass substrate may be damaged and energy consumption increases
Solution Approach 1:
The patent introduces an intermediary layer (zinc oxide or zinc stannate) between the UV radiation source and the silver layer. This intermediary layer absorbs UV radiation and converts it to heat, which is then transferred to the silver layer. This mediator protects the glass substrate from direct UV exposure while still achieving the desired heating effect on the silver layer, resolving the contradiction between improving silver quality and preventing glass damage.
Solution Approach 2:
The patent replaces traditional thermal convection heating systems with a UV radiation-based heating system. Instead of using conventional ovens or heating equipment that directly heat the glass substrate, the system uses UV lamps to irradiate the coating, which then converts the radiation to heat locally. This substitution eliminates the need for high-temperature conventional heating and prevents glass damage.
2Reliability
If IR irradiation is used to heat the silver layer, then the silver layer quality improves, but the method is ineffective due to reflection or absorption issues
Solution Approach 1:
The patent changes the wavelength parameter of the irradiation from infrared to ultraviolet range. The UV wavelength (365 nm) is specifically chosen because it is strongly absorbed by zinc oxide and zinc stannate materials, converting the irradiation energy efficiently to heat. This parameter change resolves the energy loss issue associated with IR reflection by utilizing UV absorption characteristics of the intermediary layer.
3Productivity
If sputter deposition is performed at room temperature, then the deposition rate is high and equipment cost is lower, but the silver layer quality is poor
Solution Approach 1:
The patent applies UV irradiation treatment after the sputter deposition process to improve the silver layer quality. The UV treatment is performed as a preliminary quality enhancement step that activates or anneals the deposited silver layer without requiring high-temperature processing during deposition. This allows the benefits of room temperature deposition (high rate, low cost) to be retained while achieving improved silver layer quality through subsequent UV treatment.
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
Enhances the electrical, thermal blocking, and optical properties of the silver layer, increasing its ability to reflect IR radiation and improve visible transmission, while reducing energy consumption and avoiding glass damage.
Implementation Method 1
Exposing the low-E coating to UV radiation, e.g., emitted from a UV lamp(s) and/or UV laser(s), allows for selective heating of the contact/seed layer
Implementation Method 2
selective heating of the contact/seed layer (e.g., of zinc oxide and/or zinc stannate) which in turn transfers the heat energy to the adjacent IR reflecting layer of or including silver
Implementation Method 3
selective heating of the contact/seed layer (e.g., of zinc oxide and/or zinc stannate) which in turn transfers the heat energy to the adjacent IR reflecting layer of or including silver
Data Source
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AI summary
Certain embodiments of this invention relates to a coated article including a low-emissivity (low-E) coating supported by a substrate (e.g., glass substrate) for use in a window, where the low-E coating is exposed to ultraviolet (UV) radiation in order to improve the coating's and thus the coated article's electrical, optical and/or thermal blocking properties. The low-E coating includes at least one infrared (IR) reflecting layer of or including silver which is located on and directly contacting a contact/seed layer of or including metal oxide such as zinc oxide and/or zinc stannate. Exposing the low-E coating to UV radiation, e.g., emitted from a UV lamp(s) and/or UV laser(s), allows for selective heating of the contact/seed layer which in turn transfers the heat energy to the adjacent IR reflecting layer. This heating of the silver inclusive layer improves the silver layer's electrical, optical and/or thermal blocking properties. The UV treated coated article, with its improved properties, may be used in the context of monolithic or insulating glass (1G) window units.