Conductive Laminated Glazing With Low-Visibility Ablation Lines

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Solution Overview

Problem

Current heated aeronautical glazing technologies with thin conductive layers for anti-frost and anti-fog functions suffer from visible ablation lines and geometry issues, particularly under nighttime observation conditions, which can be distracting for pilots and affect heating uniformity.

Innovation Solution

The solution involves structuring the ablation edges with a gradual thickness variation and controlled slope to minimize visibility of the ablation lines, using laser ablation or chemical methods to create parallel and equidistant conductive lines with specific widths and spacings, and employing materials like indium oxide doped with tin or zinc oxide for improved heating efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional laser ablation is used to create flux lines in the conductive layer, then the heating function is achieved, but visible ridges and heat-affected zones make the lines highly visible under certain lighting and observation conditions

Engineering Contradiction:
Improveheating functionVSAvoidvisibility of ablation lines
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the parameters of laser ablation including using picosecond or femtosecond pulse durations instead of nanosecond pulses, adjusting laser energy density, and modifying pulse overlap to eliminate ridge formation and minimize the heat-affected zone, thereby making ablation lines invisible or barely visible

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent converts the harmful thermal effects that cause ridges and visible heat-affected zones into beneficial cold ablation by using ultrafast laser pulses that remove material before significant heat diffusion occurs, transforming the thermal damage problem into a precise material removal solution

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

2Reliability

If the number of flux lines is increased to improve heating uniformity on larger surfaces, then heating effectiveness improves, but the lines become more visible and more disruptive for pilots

Engineering Contradiction:
Improveheating uniformityVSAvoidvisibility and disruption
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

By changing the ablation parameters to produce invisible lines, the patent enables increased line density without proportionally increasing visibility, allowing more lines to be placed on larger surfaces for improved heating uniformity while maintaining aesthetic appearance

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses multiple closely spaced flux lines to segment the heating function across the glazing surface, improving heating uniformity while keeping individual lines invisible through optimized ablation parameters

Inventive Principle:
Principle #1Segmentation

3Power

If the thickness of the deposited conductive layer is increased to maintain heating performance on larger glazing areas, then heating effectiveness is maintained, but the ablation lines become more visible

Engineering Contradiction:
Improveheating performanceVSAvoidvisibility of lines
Core Design Contradiction:
PowerVSObject-affected harmful factors

Solution Approach 1:

The patent changes the ablation parameters specifically to handle thicker conductive layers by adjusting laser energy density and pulse characteristics, enabling clean ablation without excessive ridges or heat-affected zones even on thicker deposits, thereby maintaining heating performance while reducing visibility

Inventive Principle:
Principle #35Parameter changes

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 makes the ablation lines less visible under various conditions, increases the number of lines per unit area, enhances heating uniformity, and reduces the electrical power required for defrosting and demisting, while maintaining effective heating performance.

Implementation Method 1

laser ablation or chemical methods to create parallel and equidistant conductive lines

Methodology Applied
Scientific EffectLaser ablation: Laser Ablation

Implementation Method 2

Preventing frost formation on aircraft glazing can be achieved by Joule heating using a thin, transparent, and electrically conductive layer

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Data Source

PatentEP3555014B1Laminated glazing having an electrically conductive layer with an ablation line, the edges of which are free of beads and gently sloped
Publication Date: 2023.09.06 SAINT GOBAIN VITRAGE SA
  • EP3555014B1 patent drawingFigure 1~3
  • EP3555014B1 patent drawingFigure 4~6
  • EP3555014B1 patent drawingFigure 7~9

AI summary

The invention relates to - laminated glazing comprising one or two sheets between 0.5 and 12 mm thick, and one or more structural sheets between 3 and 20 mm thick, wherein at least the face of at least one of the sheets that are 0.5 to 12 mm thick, oriented toward the structural sheet(s), and/or at least one face of the structural sheet(s) comprises an electrically conductive layer which is between 2 and 1600 nm thick, except over at least one ablation line, the edges of said line having no beads, and the average slope of said edges being at most equal to 5%; - a method for producing the glazing; - the application thereof as de-icing/de-misting glazing.