Photocatalytic Coating with Underlying Oxide Layer for Self-Cleaning
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Solution Overview
Problem
Current photocatalytic coatings for substrates, such as glass, lack enhanced low-maintenance properties, particularly self-cleaning and hydrophilic properties, which are desired for window coatings.
Innovation Solution
A photocatalytic coating is developed that includes a titania-containing film deposited over an underlying film comprising materials like tungsten oxide, niobium oxide, or silica, with additional dopants such as nitrogen, copper, or molybdenum, to enhance the low-maintenance properties, and a method of depositing these coatings using sputtering techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a simple titania coating is applied to glass, then the coating is easy to manufacture, but it lacks enhanced low-maintenance properties such as self-cleaning and hydrophilic properties
Solution Approach 1:
The patent applies composite materials by combining titania with underlying films of tungsten oxide, niobium oxide, or silica, and incorporating dopants such as nitrogen, copper, or molybdenum into the titania film. This composite structure enhances the low-maintenance properties including self-cleaning and hydrophilic characteristics while maintaining manufacturability through established sputtering techniques.
2Reliability
If additional materials and dopants are incorporated into the photocatalytic film to enhance low-maintenance properties, then self-cleaning and hydrophilic properties are improved, but the device complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the coating into distinct functional layers: an underlying film (tungsten oxide, niobium oxide, or silica) and a photocatalytic titania film with dopants. This segmented structure allows each layer to contribute specific properties while maintaining overall system manageability and enhancing low-maintenance performance.
3Reliability
If the underlying film thickness is reduced to less than 250 angstroms for optimal performance, then the low-maintenance properties are enhanced, but the manufacturing precision requirements increase
Solution Approach 1:
The patent applies parameter changes by optimizing the thickness of the underlying film to less than 250 angstroms (preferably less than 75 angstroms) and controlling dopant concentrations at specific levels (e.g., up to 5%, such as 2%). These precise parameter specifications enhance the low-maintenance properties while providing clear manufacturing targets for consistent performance.
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 coating achieves improved self-cleaning and hydrophilic properties, maintaining durability and adhesion, while being suitable for various substrates including glass sheets, with the underlying films being less than 250 angstroms thick for optimal performance.
Implementation Method 1
a method of depositing a photocatalytic coating is also provided. In some embodiments, the method comprises depositing a film comprising tungsten oxide over a major surface of a glass sheet
Implementation Method 2
Photocatalytic coatings are known in the art. These coatings commonly include a film of titania on a substrate
Implementation Method 3
Desirable low-maintenance properties include self-cleaning properties, hydrophilic properties, etc.
Data Source
AI summary
The invention provides a substrate bearing a photocatalytic coating. In some embodiments, the coating includes a photocatalytic film comprising titania deposited over a layer comprising tungsten oxide, aluminum oxide, niobium oxide or zirconium oxide. Additionally or alternatively, the photocatalytic film can include both titania and a material selected from the group consisting of nitrogen, tantalum, copper and silica. The invention also provides methods of depositing such coatings.