Laminated Vehicle Glazing with Pyrolytic Coating and Foil Busbar
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Solution Overview
Problem
Existing laminated vehicle glazings with electrically conductive coatings or wires for heating purposes often suffer from optical distortion and premature failure due to busbar damage during lamination, especially in larger glazings, leading to hot and cold spots and increased manufacturing costs.
Innovation Solution
A laminated vehicle glazing with a pyrolytically deposited transparent conductive oxide layer on one glass ply and conductive foil busbars in direct contact with both the coating and interlayer ply, which enhances electrical contact and robustness, reducing the likelihood of coating breakdown and failure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wires or thin tracks of electrically conductive ink are used to provide heating function, then the glazing can be heated electrically, but optical distortion occurs and polymer interlayer properties are affected
Solution Approach 1:
The patent changes the physical state and deposition method of the conductive coating from vacuum-deposited metal layers to pyrolytically deposited organic conductive coatings. This parameter change transforms the coating into a flexible, conformal layer that can be applied in thick coatings without optical distortion, while maintaining electrical conductivity for heating function.
Solution Approach 2:
The patent uses screen-printed silver paste coatings as a disposable-like solution where the conductive pattern is directly printed and fired onto the glass. This approach accepts some material loss and process variability but eliminates the need for complex vacuum deposition equipment and multi-layer structures, reducing overall system complexity and cost.
2Ease of operation
If busbars are used to connect power supply to conductive coating, then electrical connection is established, but busbars may damage the sputtered coatings during lamination causing hot and cold spots
Solution Approach 1:
The patent applies the conductive coating to the glass surface before lamination, allowing the coating to be firmly bonded to the glass in advance. This preliminary action ensures that when busbars are later pressed against the glass during assembly, the pre-bonded coating remains intact and undamaged, preventing hot and cold spots.
Solution Approach 2:
The patent uses the glass substrate itself as a cushioning layer between the busbar and the conductive coating. The glass absorbs and distributes the pressure from the busbar, preventing direct mechanical damage to the conductive coating while maintaining electrical contact through the glass-coating interface.
3Ease of operation
If silver printed busbars are used to contact the coating directly, then electrical connection is achieved, but manufacturing process becomes more complex and expense increases
Solution Approach 1:
The patent merges the conductive coating application and busbar attachment into a single lamination process step. The conductive coating is applied to the glass, then the busbar is pressed against the glass-coating assembly during lamination, combining multiple operations into one integrated process that reduces complexity and cost.
Solution Approach 2:
The patent replaces complex mechanical alignment and attachment systems with a simplified pressure-sensitive bonding approach. Instead of requiring precise mechanical alignment of busbars with conductive traces, the flexible printed coating conforms to the busbar surface under pressure, eliminating complex alignment mechanisms.
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 improved electrical contact and robustness, reducing the failure rate of laminated vehicle glazings, especially in larger sizes, by using pyrolytically deposited coatings and metal foil busbars, ensuring consistent heating performance and extended service life.
Implementation Method 1
the electrically conductive coating comprises a pyrolytically deposited transparent conductive oxide layer
Implementation Method 2
the first busbar is in direct contact with both the electrically conductive coating and the interlayer ply
Data Source
AI summary
A laminated vehicle glazing is disclosed, the glazing comprising a first glass ply coated with an electrically conductive coating, a second glass ply, an interlayer ply comprising polyvinyl butyral, and a first busbar comprising a conductive foil, wherein the electrically conductive coating comprises a pyrolytically deposited transparent conductive oxide layer and in that the first busbar is in direct contact with both the electrically conductive coating and the interlayer ply. Preferably the pyrolytically deposited transparent oxide layer comprises doped tin oxide and is the outermost layer of the electrically conductive coating. Also disclosed are a vehicle windshield and a train having a power supply at 25 V to 250 V, comprising a laminated vehicle glazing. A method for manufacturing a laminated vehicle glazing is also disclosed.