Heating Layer Segmentation for Uniform Vehicle Windshield Temperature

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Solution Overview

Problem

Vehicle windshields with electrical heating layers experience inhomogeneous heating power distribution due to uncoated zones, leading to reduced heating efficiency and potential thermal stresses, which can impair visibility and safety.

Innovation Solution

Incorporating dividing lines that electrically divide the heating layer into segments, with at least one segment arranged in a strip shape around uncoated zones to guide the current path and ensure more uniform heating, along with additional busbars and low-resistance bridges to optimize current flow and reduce thermal inhomogeneities.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of information

If uncoated zones are introduced to improve electromagnetic radiation transparency for data communication, then radio data transmission is enabled, but heating power distribution becomes highly inhomogeneous with reduced heating power below and in the vicinity of the uncoated areas

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

Solution Approach 1:

The heating layer is divided into multiple segments by dividing lines, creating a first segment above the uncoated zone, a second segment below the uncoated zone, and optionally a third segment adjacent to the uncoated zone. This segmentation allows independent control of current paths in different regions, enabling the third segment to be specifically optimized to guide current around the uncoated zone and compensate for the heating deficiency below it.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different segments of the heating layer are assigned different electrical resistance values to achieve localized optimization. The third segment adjacent to the uncoated zone is given a higher electrical resistance than the first and second segments, which causes more current to flow through this segment and thereby compensates for the reduced heating power in the area below the uncoated zone, achieving uniform overall heating distribution.

Inventive Principle:
Principle #3Local quality

2Loss of information

If uncoated zones are introduced to allow electromagnetic radiation transmission, then data communication is enabled, but areas with particularly high current density occur causing greatly increased heating power and very high local pane temperatures

Engineering Contradiction:
Improveradio data transmission capabilityVSAvoidlocal pane temperature
Core Design Contradiction:
Loss of informationVSTemperature

Solution Approach 1:

The heating layer is divided into multiple segments by dividing lines, creating a first segment above the uncoated zone, a second segment below the uncoated zone, and optionally a third segment adjacent to the uncoated zone. This segmentation allows independent control of current paths in different regions, enabling the third segment to be specifically optimized to guide current around the uncoated zone and compensate for the heating deficiency below it.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different segments of the heating layer are assigned different electrical resistance values to achieve localized optimization. The third segment adjacent to the uncoated zone is given a higher electrical resistance than the first and second segments, which causes more current to flow through this segment and thereby compensates for the reduced heating power in the area below the uncoated zone, achieving uniform overall heating distribution.

Inventive Principle:
Principle #3Local quality

3Power

If the heating layer is structured with dividing lines or zones to form coiled current paths, then electrical resistance is increased and current path contact is improved, but device complexity increases

Engineering Contradiction:
Improveelectrical resistanceVSAvoidheating layer structure complexity
Core Design Contradiction:
PowerVSDevice complexity

Solution Approach 1:

The heating layer is divided into a small number of segments (first, second, and optionally third segments) by dividing lines, which is a simpler approach than traditional coiled current paths. This segmentation provides sufficient electrical resistance and current distribution control while maintaining manufacturing simplicity and avoiding excessive structural complexity.

Inventive Principle:
Principle #1Segmentation

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 approach achieves a more homogeneous heating power distribution and temperature uniformity, enhancing defrosting and anti-fogging capabilities while minimizing visual impairment and thermal stresses, thus improving the safety and effectiveness of vehicle windshields in adverse weather conditions.

Implementation Method 1

at least one electrical heating layer made of an electrically conductive coating for heating the first disk

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 2

at least one dividing line that electrically divides the electric heating layer into at least two segments

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentEP2936925B1Glasspane with electrical heating layer
Publication Date: 2021.05.05 SAINT GOBAIN VITRAGE SA
  • EP2936925B1 patent drawingFigure 1A~1B
  • EP2936925B1 patent drawingFigure 1C
  • EP2936925B1 patent drawingFigure 2A

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 first surface (III); at least one electric heating layer (3) that is applied to at least part of the surface (III) and comprises an 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 at least one separating line (9.n) which electrically subdivides the electric layer (3) into at least two segments (10.n, 10.n+1), n being an integer ≥ 1. At least one segment (10.n) is arranged in the form of a strip 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).