Windshield Coating Stack for Low-Voltage De-Icing

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Solution Overview

Problem

Conventional heatable vehicle windshields face issues such as visible wires affecting aesthetics and visibility, increased complexity and cost due to high sheet resistance of transparent conductive coatings, and insufficient heating with standard alternators.

Innovation Solution

A coated transparency with a specific silver layer thickness between 30 nm and 60 nm, combined with a coating stack design that maintains low sheet resistance and high light transmittance, allowing de-icing with a 14v alternator.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional heated windshields use a single-layer resistive heating element, then the structure is simple, but the heating uniformity is poor and ice/shove removal effectiveness is insufficient

Engineering Contradiction:

Improveice and snow removal effectivenessVSAvoidheating element structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The heating element is divided into multiple heating layers (typically three layers) with different orientations. Each layer contains heating elements arranged in different directions (e.g., horizontal, diagonal, vertical), creating a segmented structure that provides multi-directional heating coverage to improve ice and snow removal effectiveness while maintaining reasonable structural complexity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the windshield receive different heating patterns through the multi-layer structure. The heating elements in each layer are strategically oriented to address specific heating needs in different areas, creating local quality variations that optimize overall heating uniformity and effectiveness.

Inventive Principle:

Principle #3Local quality

2Manufacturing precision

If the heating element uses a multi-layer structure with different orientations, then heating uniformity improves, but the manufacturing complexity increases

Engineering Contradiction:

Improveheating uniformityVSAvoidassembly process

Core Design Contradiction:

Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The multi-layer heating elements are nested within each other in a compact arrangement, with each layer positioned at a specific depth or distance from the windshield surface. This nesting approach allows multiple heating layers to be integrated into a single assembly unit, improving heating uniformity while managing manufacturing complexity through systematic layer integration.

Inventive Principle:

Principle #7Nested doll (Nesting)

Solution Approach 2:

Multiple heating layers with different orientations are merged into a single integrated heating assembly. The layers are combined in such a way that they function as a unified system, achieving improved heating uniformity through the combined effect of multi-directional heating elements while simplifying the overall manufacturing process through integration.

Inventive Principle:

Principle #5Merging (Combining)

3Reliability

If heating elements are positioned closer to the outer surface, then ice and snow removal effectiveness improves, but electrical insulation requirements increase

Engineering Contradiction:

Improveice and snow removal effectivenessVSAvoidelectrical insulation requirements

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

An intermediary insulating layer or protective coating is introduced between the heating elements and the outer windshield surface. This intermediary structure allows the heating elements to be positioned closer to the surface for improved ice and snow removal effectiveness while providing the necessary electrical insulation to meet safety requirements.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

A thin film or flexible insulating shell is applied over or around the heating elements to provide electrical insulation. This thin protective layer enables closer positioning of heating elements to the outer surface for better heating effectiveness while maintaining adequate insulation through the film barrier.

Inventive Principle:

Principle #30Flexible shells and thin films

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

The solution provides effective de-icing without visible wires, maintains high light transmittance, and avoids the need for voltage upgrades, reducing complexity and cost.

Implementation Method 1

a heating element positioned at a first location within the windshield

Methodology Applied

Scientific EffectJoule heating: Joule Heating

Implementation Method 2

a wiper blade positioned at a second location within the windshield, the wiper blade being positioned to contact the outer surface of the windshield

Methodology Applied

Scientific EffectFriction: Friction

Data Source

PatentEP3948372B1Heatable windshields

Publication Date: 2026.05.06 VITRO FLAT GLASS LLC

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AI summary

A coated article includes a substrate, a first dielectric layer, a first metallic layer, a first primer layer, a second dielectric layer, a second metallic layer, a second primer layer, a third dielectric layer, a third primer layer, a third metallic layer, and a fourth dielectric layer. The total combined thickness of the metallic layers is at least 30 nanometers and no more than 60 nanometers. The article can have a sheet resistance of less than 0.85 Ω/⩽, a visible light reflectance of not more than 10%, and a visible light transmittance of at least 70%.