Wired Laminated Window with Variable Wire Pitch for Uniform Heating

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Solution Overview

Problem

Electrically heatable windows with conductive elements often suffer from non-uniform heating, leading to hotspots and optical distortion, which can cause safety hazards and degrade visibility, especially when used in vehicles.

Innovation Solution

The design features an array of spaced wires with varying pitch, including a wire-free area aligned with a portion of the array where the wire pitch is greater than in other portions, ensuring improved heating uniformity by adjusting the length and pitch of the wires to reduce hotspots and optical distortion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of information

If a wire-free area is created in the window for data transmission, then data transmission capability is improved, but non-uniform heating and hotspots occur due to resistance differences in the wire array

Engineering Contradiction:
Improvedata transmission capabilityVSAvoidheating uniformity
Core Design Contradiction:
Loss of informationVSTemperature

Solution Approach 1:

The patent applies local quality by varying the pitch of wires in different regions of the window. Specifically, the wire array has a first pitch in regions adjacent to the wire-free area and a second pitch in other regions, where the pitches differ to compensate for resistance variations. This ensures uniform power density and heating across the entire window surface, including areas adjacent to the wire-free data transmission zone.

Inventive Principle:
Principle #3Local quality

2Temperature

If the wire pitch is increased to reduce heating in certain areas, then heating uniformity is improved, but the overall heating effectiveness of the window decreases

Engineering Contradiction:
Improveheating uniformityVSAvoidheating effectiveness
Core Design Contradiction:
TemperatureVSPower

Solution Approach 1:

The patent maintains high overall heating effectiveness by using local quality principles to adjust wire pitch only in specific regions. The wire array incorporates different pitches selectively - a first pitch in certain regions and a second pitch in other regions - rather than uniformly increasing pitch across the entire window. This localized adjustment achieves heating uniformity without sacrificing overall heating power.

Inventive Principle:
Principle #3Local quality

3Reliability

If conductive elements are added to the window for heating, then anti-condensation and anti-ice capability is improved, but signal transmission through the window is degraded or blocked

Engineering Contradiction:
Improveanti-condensation and anti-ice capabilityVSAvoidsignal transmission quality
Core Design Contradiction:
ReliabilityVSLoss of information

Solution Approach 1:

The patent applies the extraction principle by creating a wire-free area within the window structure that is free from conductive heating elements. This dedicated zone allows electromagnetic signals to pass through without interference from the heating wires, while the rest of the window maintains its heating capability through the surrounding wire array.

Inventive Principle:
Principle #2Taking out (Extraction)

4Area of stationary object

If a wire array is used for heating, then heating coverage is improved, but optical distortion occurs due to non-uniform temperature distribution

Engineering Contradiction:
Improveheating coverageVSAvoidoptical clarity
Core Design Contradiction:
Area of stationary objectVSStability of the object's composition

Solution Approach 1:

The patent prevents optical distortion by applying local quality through spatially varying wire pitch. The wire array has different pitches in different regions - a first pitch in some areas and a second pitch in other areas - which compensates for resistance variations and ensures uniform power density and temperature distribution across the entire heated area, thereby maintaining optical clarity.

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 approach significantly enhances heating uniformity, reducing the risk of injury from hotspots and optical distortion, while allowing data transmission through the window by creating a wire-free area for devices like cameras and sensors.

Implementation Method 1

The array of spaced wires extending between the first busbar and the second busbar... electrically heatable window

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Data Source

PatentEP3516926B1Wired laminated window
Publication Date: 2020.07.15 PILKINGTON GRP LTD
  • EP3516926B1 patent drawingFigure 1
  • EP3516926B1 patent drawingFigure 2
  • EP3516926B1 patent drawingFigure 3

AI summary

An electrically heatable window including two plies of glazing material, a ply of interlayer material located between the plies of glazing material, a first busbar and a second busbar, and an array of spaced wires extending between the first busbar and the second busbar. The window comprises a wire-free area aligned with the first portion and the array of spaced wires includes a first portion and a second portion. To reduce heating non-uniformity, the pitch of the wires of the first portion is greater than the pitch of the wires of the second portion. Also disclosed is a method for forming the electrically heated window and vehicles comprising the electrically heated window.