Heated Windshield Segmented Heating Layer for Uniform Heat Distribution

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Solution Overview

Problem

Heated vehicle windshields with uncoated zones for electromagnetic radiation transparency result in inhomogeneous heat output distribution, leading to local hotspots and potential thermal stresses, which can impair the windshield and affect radio data traffic.

Innovation Solution

A vehicle windshield with an electrically heated layer featuring busbars and dividing lines that subdivide the heating layer into segments around uncoated zones, ensuring a uniform current path and heat distribution, with the width of segments calculated to maintain a consistent heat output across the windshield.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of information

If uncoated zones are introduced to improve electromagnetic radiation transparency, then radio data communication is enabled, but heating power distribution becomes inhomogeneous with local hotspots and reduced heating power below uncoated areas

Engineering Contradiction:
Improveradio data communicationVSAvoidheating power distribution uniformity
Core Design Contradiction:
Loss of informationVSManufacturing precision

Solution Approach 1:

The heating layer is divided into multiple segments by dividing lines that extend from the edges toward the uncoated zone. This segmentation creates separate current paths that bypass the uncoated zone, distributing current flow more evenly across the heating layer and preventing both the loss of heating power below uncoated areas and the formation of excessive hotspots in adjacent regions.

Inventive Principle:
Principle #1Segmentation

2Device complexity

If the heating layer is structured with dividing lines to increase electrical resistance and enable smaller terminal electrodes, then device complexity is reduced, but the current path length increases and manufacturing precision requirements increase

Engineering Contradiction:
Improveterminal electrode sizeVSAvoidsegment width uniformity
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The dividing lines are designed with varying characteristics: in the upper region, they extend fully from the edge toward the uncoated zone to create effective segmentation and control current paths. In the lower region, they are interrupted or have reduced extent to maintain adequate current flow and heating power. This local variation in dividing line configuration allows the system to achieve both reduced terminal electrode requirements and acceptable manufacturing precision.

Inventive Principle:
Principle #3Local quality

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 achieves a more homogeneous heat output distribution, reducing the risk of thermal stresses and improving the windshield's ability to clear ice and fog while minimizing interference with radio data traffic.

Implementation Method 1

An external voltage source can pass an electric current through the electrically conductive coating, heating the coating and thus the pane

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 2

the current path for the heating current is at least partially around the uncoated zone, achieving a more homogeneous heat output distribution

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP2936926B1Glasspane with electrical heating layer
Publication Date: 2019.01.16 SAINT GOBAIN VITRAGE SA
  • EP2936926B1 patent drawingFigure 1
  • EP2936926B1 patent drawingFigure 2
  • EP2936926B1 patent drawingFigure 3

AI summary

The present invention relates to a pane (100) having an electric heating layer (3) and comprising at least: a first pane (1) having a surface (III); at least one electric heating layer (3) that is applied to at least part of the surface (III) and comprises at least one uncoated zone (8); at least two busbars (5.1, 5.2), provided for connection to a voltage source (14), which are connected to the electric heating layer (3) such that a current path (11) for a heating current is formed between the busbars (5.1, 5.2); and n separating lines (9.n) which electrically subdivide the electric layer (3) into m segments (10.m), n being an integer > 1 and m = n+1. The segments (10.m) are arranged in the form of strips around the uncoated zone (8) such that the current path (11) for the heating current is at least partially guided around the uncoated zone (8) and the segments (10.m) have equal width (b) and the sum of widths (b) of segments (10.m) is equal to the width (B) of the electric heating layer (3). Nothing to translate