Heated Windshield Wiper Rest Area Heating System
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Solution Overview
Problem
Existing windscreens with electrically conductive layers face challenges in achieving sufficient power for defrosting and demisting, particularly in modern windshields with larger dimensions, while maintaining transparency and optical quality, and avoiding short-circuits and optical defects during the bending process.
Innovation Solution
The implementation of a system where heating wires and conductive layers remain in electrical contact without short-circuiting, with the wires only contacting parts of the layer that offer less resistance, and the use of a sparse network of lines to minimize the surface without layers, ensuring minimal disruption to the glass sheet's behavior during bending.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the metal layer thickness is increased to reduce resistance and increase heating power, then the heating power is improved, but the light transmission in the visible wavelength range decreases below regulatory requirements
Solution Approach 1:
The heating function is segmented into two distinct systems: a first heating system using conductive layers for general windshield heating, and a second heating system using heating wires for intensive heating of the wiper rest area. This segmentation allows each system to operate at optimal parameters without compromising the other - the conductive layers maintain light transmission while the heating wires provide intensive local heating where needed.
2Power
If multiple busbars are placed close together to increase power per unit area in the wiper rest area, then the heating power is improved, but the device complexity and visual appearance are worsened
Solution Approach 1:
Heating wires act as an intermediary solution between the conductive layers and the busbars. The heating wires are electrically connected to the busbars and conductive layers while being physically isolated from them through the interlayer, allowing power transfer without visual interference or short-circuit risks. This intermediary approach simplifies the overall structure compared to multiple close-spaced busbars.
3Ease of manufacture
If heating wires are arranged in contact with conductive layers to enable electrical connection, then the ease of manufacture is improved, but the risk of short-circuiting increases
Solution Approach 1:
The heating wires are nested within the laminated structure at position 2, between the glass sheet and the conductive layers at position 3, with both elements ultimately embedded in the thermoplastic interlayer. This nested arrangement allows electrical connection through the conductive interlayer material while providing multiple layers of physical separation and insulation, dramatically reducing short-circuit risk compared to direct contact arrangements.
4Ease of manufacture
If the conductive layers are removed in the wiper rest area to allow heating wire placement, then the ease of manufacture is improved, but the optical quality and appearance are worsened
Solution Approach 1:
The conductive layers are selectively removed only in the specific zone corresponding to the wiper rest area, while maintaining full coverage in the rest of the windshield. This local modification allows heating wire placement and electrical connection exactly where needed without compromising the optical quality of the entire windshield, as the uncoated area is confined to the already-shadowed wiper rest zone.
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 configuration allows for efficient heating of the windscreen wiper rest area, maintaining optical quality and preventing short-circuits, while ensuring the glass sheet behaves similarly to uniformly coated surfaces during bending, achieving rapid defrosting and complete removal of frost.
Implementation Method 1
a well-recognized difficulty is the need to achieve layers whose resistance is low enough to make it possible to have an appropriate power. The power developed is limited by the voltage available on the vehicle
Implementation Method 2
the need to achieve layers whose resistance is low enough to make it possible to have an appropriate power
Implementation Method 3
windscreens which comprise a system of electrically conductive thin layers... initially developed to impart infrared ray filtering properties
Data Source
Figure 1~4
AI summary
The invention relates to a heated laminated windshield formed by two sheets of glass joined by an intermediate thermoplastic sheet. The windshield comprises: a conductive layer system which covers the majority of the surface of one glass sheet of the windshield and which is powered by busbars; and a network of heating wires, which is in contact with the layer system and not insulated electrically therefrom, said network being located in the wiper rest area. The two heating means, the layer system and the wire network are all located on the same side of the intermediate thermoplastic sheet. In addition, lines are provided in the area corresponding to the wiper rest area in order locally to break the electrical continuity of the conductive layer system, said lines and the heating wire network being disposed such that the current being supplied to the heating wires flows along the entire length of the wires, electrically insulating the heating wires from the busbars and the wire loops from one another.