Variable Width Flow Lines in Heated Glazing
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Solution Overview
Problem
Existing heated glazings for transportation vehicles and buildings face challenges in achieving uniform power density, particularly in complex shapes and corner zones, leading to inefficient heating and potential cold spots.
Innovation Solution
A laminated glazing with a variable width electrically conductive layer and flow lines, which allows for controlled adjustment of resistance and power density by varying the width of the flow lines using techniques such as laser ablation or chemical stripping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a uniform electrically conductive layer is used for heating, then the manufacturing process is simple, but the power density becomes non-uniform especially in corner zones creating cold spots
Solution Approach 1:
The patent applies local quality by creating zones with different electrical resistance values within the conductive layer. Specifically, corner zones are designed with higher resistance (through reduced material thickness or increased resistivity) to compensate for the lower power density that would otherwise occur in these areas, thereby achieving uniform power distribution across the entire glazing surface including corners and edges
2Power
If the overall resistance of the electrically conductive layer is reduced to increase power output, then the heating power increases, but the power consumption becomes excessively high
Solution Approach 1:
The patent implements local quality by spatially varying the electrical resistance across the conductive layer. Different zones (corner zones, edge zones, central zones) are assigned different resistance values matched to their specific heating requirements. This allows the system to achieve adequate heating power output while maintaining controlled overall resistance to limit excessive power consumption, as each zone receives only the power it needs
3Manufacturing precision
If flow lines are produced to guide electric current and uniform power density, then heating uniformity improves, but the manufacturing complexity increases
Solution Approach 1:
The patent extracts the current-guiding function from separate flow line structures and integrates it directly into the conductive layer itself. The conductive layer is designed with spatially varying resistance properties that inherently guide current flow and distribute power uniformly without requiring additional flow line elements, thereby achieving heating uniformity while reducing manufacturing complexity
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
This solution enables uniform power density across the glazing surface, including corner zones, reducing cold spots and ensuring that the nominal power consumption does not exceed a maximum value.
Implementation Method 1
The heating system is formed, for example, of wires screen-printed on the monolithic glazing or embedded in an interlayer adhesive layer of the laminated glazing, or of transparent conductive layers (doped oxides: indium oxide doped with tin -'Indium Tin Oxide': ITO-, AZO (Aluminum Zinc Oxide), SnO2: F, or metals, such as silver, or optionally in identical or different multilayers), making possible heating by the Joule effect.
Implementation Method 2
the electrically conductive layer exhibiting flow lines for guiding the electric current between the busbars
Data Source
AI summary
A laminated glazing is formed of several rigid transparent substrates adhesively bonded in pairs by an interlayer adhesive layer, at least one of these transparent substrates being coated with an electrically conductive layer, a zone of this transparent substrate exhibiting four opposite edges in pairs, a first and a second busbar being positioned along two opposite edges, the electrically conductive layer exhibiting flow lines for guiding the electric current between the busbars, the set of flow lines being of variable width.