Silver Multilayer Windshield Coating for 14V De-Icing
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Solution Overview
Problem
Conventional heatable vehicle windshields face issues such as aesthetically undesirable visible wires, reduced total solar energy transmission (TSET), and the need for higher voltage alternators to effectively de-ice.
Innovation Solution
A coated transparency with a specific configuration of metallic silver layers in the coating stack, optimizing the sheet resistance to allow de-icing with a 14V alternator while maintaining light transmittance above 70%.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wire-heated windshields are used, then de-icing function is provided, but wires are visible and aesthetics are degraded
Solution Approach 1:
The patent extracts the heating function from visible wire structures and integrates it into a transparent conductive coating layer, eliminating the visual obstruction while maintaining the de-icing capability through electrical resistance heating of the coating material
Solution Approach 2:
The patent replaces the mechanical wire structure with a thin-film conductive coating deposited on the glass surface, transitioning from a discrete mechanical heating element to a continuous electromagnetic-based heating layer that is optically transparent
2Ease of manufacture
If wire diameter is decreased to reduce visibility, then aesthetics improve, but number of wires must increase and TSET decreases
Solution Approach 1:
The patent employs a composite coating structure combining transparent conductive materials with specific optical properties, achieving both aesthetic transparency and adequate electrical conductivity for heating without blocking solar energy transmission
3Ease of manufacture
If conventional transparent conductive coatings are used, then aesthetics improve, but sheet resistance is too high for 14V alternator de-icing
Solution Approach 1:
The patent modifies the electrical parameters of the conductive coating by adjusting material composition, layer thickness, and conductivity to achieve optimal sheet resistance values that enable effective de-icing with standard 14V alternators while maintaining optical transparency
4Reliability
If silver thickness is increased to lower sheet resistance, then de-icing capability improves, but transmittance decreases below 70%
Solution Approach 1:
The patent optimizes the thickness parameter of silver layers to a specific range that balances electrical conductivity for effective heating with optical transparency to maintain adequate light transmission and prevent unwanted coloration
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 the sheet resistance of the coated transparency, enabling de-icing without the need for higher voltage alternators, while preserving the aesthetic appeal and solar energy transmission of the windshield.
Implementation Method 1
Passing electric current through a conductor on a laminated vehicle windshield will raise the temperature of the windshield
Implementation Method 2
A coated article comprising a substrate. The coated article is coated with at least one dielectric layer positioned over the substrate, and at least one metallic layer(s)
Data Source
AI summary
A coated article includes a substrate, a first dielectric layer, a first metallic layer, a first primer layer, a second dielectric layer, a second metallic layer, a second primer layer, a third dielectric layer, a third primer layer, a third metallic layer, and a fourth dielectric layer. The total combined thickness of the metallic layers is at least 30 nanometers and no more than 60 nanometers. The article can have a sheet resistance of less than 0.85Ω/□, a visible light reflectance of not more than 10%, and a visible light transmittance of at least 70%.