Transparent Pane with Segmented Heatable Coating and Wiper Zone Heating
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Solution Overview
Problem
Existing transparent panes with electrically heatable coatings in vehicles face challenges in achieving sufficient heating power in areas where windshield wipers are parked, leading to potential icing due to the design of busbars and heating coatings, which restricts heating efficiency and compliance with legal requirements.
Innovation Solution
A transparent pane design with a heatable coating divided by a coating-free zone into separate galvanically isolated zones, each connected to busbars, and an additional heating element in the coating-free zone to enhance heating efficiency, allowing for uniform heating of the pane, including areas with busbars that typically do not contribute to heating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the heating voltage is increased to achieve sufficient heating power, then the heating output is improved, but the available on-board voltage is limited to 12-24 volts
Solution Approach 1:
The heatable coating is divided into multiple separate heating fields by coating-free zones, with each field independently connected to busbars. This segmentation allows the total heating power requirement to be distributed across multiple zones, achieving sufficient overall heating output without requiring excessive voltage in any single zone.
Solution Approach 2:
Different regions of the pane are provided with different heating characteristics. The central field of vision receives heating from the heatable coating, while the wiper rest area receives additional heating from dedicated heating elements in coating-free zones. This local differentiation optimizes heating efficiency for each specific area's requirements.
2Power
If the layer thickness of the heatable coating is increased to reduce surface resistance, then the surface resistance is reduced, but the optical transmission of the pane is reduced
Solution Approach 1:
The heatable coating is segmented into separate heating fields by coating-free zones. This allows the coating thickness to be optimized for heating performance in specific areas (like the wiper rest zone) without compromising overall optical transmission, as the coating is not continuous across the entire pane surface.
Solution Approach 2:
The heatable coating is applied with different characteristics in different areas. In the central field of vision, the coating maintains optimal thickness for balancing heating and transmission. In the wiper rest area, additional heating elements in coating-free zones provide enhanced heating without affecting the optical properties of the main viewing area.
3Power
If the busbars are arranged along the longer sides of the window to reduce current path length, then the heating output is improved, but the heating power in the wiper rest area is insufficient
Solution Approach 1:
The heating system is divided into separate heating fields, with dedicated heating elements placed in the coating-free zone corresponding to the wiper rest area. This segmentation ensures that the wiper area receives independent heating coverage regardless of busbar placement for the main field of vision.
Solution Approach 2:
Coating-free zones serve as intermediaries that host additional heating elements. These zones act as mediators between the busbar system and the wiper rest area, providing the necessary heating power to this previously underheated region through thermally conductive heating elements.
4Power
If additional busbars are added to heat the masked area below the field of vision, then the heating coverage is improved, but the device complexity increases
Solution Approach 1:
The coating-free zones serve multiple functions: they electrically isolate adjacent heating fields, provide mounting areas for additional heating elements, and enable extended heating coverage without requiring additional busbars in every area. This multi-functionality reduces overall system complexity.
Solution Approach 2:
The heatable coating and heating elements are designed to self-distribute heat to adjacent areas through thermal conduction. The heating elements in the coating-free zones automatically provide heat to the masked areas below the field of vision without requiring separate active heating components in those regions.
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 design significantly improves heating efficiency, particularly in the area of windshield wipers, preventing icing and ensuring effective de-icing of vehicle windshields while maintaining optical transmission and compliance with legal requirements.
Implementation Method 1
The heatable coating, which consists of metal or metal oxide, for example, can be formed as a single layer or can be composed of a layer sequence that includes at least one such single layer
Implementation Method 2
a surface area of the pane adjoining this, which has a heatable coating but contains a busbar that does not contribute significantly to the heating output and does not belong to a heating field, can also be heated by the heating element
Data Source
Figure 1
Figure 1A
Figure 2
AI summary
The invention relates to a transparent panel having a transparent heatable coating, which extends at least over a part of the panel surface, in particular the visual field. The heatable coating is divided by at least one heatable coating-free zone into at least one first heatable coating zone and a second heatable coating zone, wherein each of the two heatable coating zones is electrically connected to at least two collecting conductors such that, after a supply voltage that is provided by a voltage source is applied, a current flows over both at least one first heating field formed by the first heatable coating zone and at least one second heating field formed by the second heatable coating zone. At least one heating element is arranged in the heatable coating-free zone, the ohmic resistance of said heating element being such that the panel can be heated in a surface area containing the heatable coating-free zone by applying the supply voltage to the heating element. The at least one heating element is designed such that, by applying the supply voltage to the heating element, the panel can also be heated in at least one surface area that adjoins the heatable coating-free zone and contains at least one of the collecting conductors.