Tinted Vehicle Glazing with Iron Oxide for Sensor Compatibility

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Solution Overview

Problem

Current tinted laminated vehicle glazings that meet solar control and optical sensor compatibility requirements become excessively thick when attempting to reduce weight, leading to unacceptably high energy transmission when thinned, and increasing iron content in the tinted glass ply either fails to meet energy transmission requirements or drops transmission below 30% in the desired spectrum.

Innovation Solution

A laminated vehicle glazing construction featuring a tinted glass ply with 0.70 to 1.0% total iron, 0 to 1.0% titania, and 0 to 2.0% ceria, combined with a clear interlayer material, achieving a transmittance of at least 30% in the 400 to 2100 nm range and 32% in the 750 to 1300 nm range, while maintaining visible light transmittance above 70% and total energy transmittance below 60%, even at reduced thicknesses.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of moving object

If the thickness of the tinted glass ply is reduced to decrease weight, then weight is reduced, but total energy transmission increases to an unacceptably high level

Engineering Contradiction:
Improveweight of glazingVSAvoidtotal energy transmission
Core Design Contradiction:
Weight of moving objectVSLoss of energy

Solution Approach 1:

The patent uses a composite glazing structure consisting of a tinted glass ply combined with a PVB interlayer. The tinted glass ply contains specific iron oxide (0.3-0.8% by weight) and titanium dioxide (0.1-0.5% by weight) to provide solar control properties. The PVB interlayer acts as an additional barrier to heat transmission. This composite approach allows weight reduction through optimized thickness while maintaining energy transmission control through the combined properties of both materials.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent changes the chemical composition parameters of the glass by precisely controlling the content of iron oxide (0.3-0.8% by weight) and titanium dioxide (0.1-0.5% by weight). These parameter changes alter the optical and thermal properties of the glass, enabling it to provide adequate solar control even at reduced thicknesses. The specific ratio and concentration of these oxides are optimized to balance weight reduction with energy transmission requirements.

Inventive Principle:
Principle #35Parameter changes

2Loss of energy

If the iron content in the tinted glass ply is increased to reduce total energy transmission, then total energy transmission decreases, but transmission in the 400 to 2100 nm range drops below 30%

Engineering Contradiction:
Improvetotal energy transmissionVSAvoidtransmission in wavelength range 400 to 2100 nm
Core Design Contradiction:
Loss of energyVSIllumination intensity

Solution Approach 1:

The patent combines iron oxide and titanium dioxide in specific proportions within the glass matrix. Iron oxide provides solar absorption, while titanium dioxide enhances the optical properties and provides additional solar control. This composite material approach allows fine-tuning of the transmission characteristics to simultaneously achieve low total energy transmission and adequate transmission in the 400-2100 nm range for optical sensor compatibility.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent precisely controls the concentration parameters of iron oxide (0.3-0.8% by weight) and titanium dioxide (0.1-0.5% by weight) to optimize the transmission profile. By adjusting these parameters within specific ranges, the glass achieves the dual requirement of blocking sufficient solar energy while maintaining at least 30% transmission in the 400-2100 nm wavelength range required for optical sensor operation.

Inventive Principle:
Principle #35Parameter changes

3Ease of manufacture

If a green-tinted glazing is used to reduce obvious coloring, then aesthetic appeal is improved, but total energy transmission may exceed acceptable limits

Engineering Contradiction:
Improveaesthetic appealVSAvoidtotal energy transmission
Core Design Contradiction:
Ease of manufactureVSLoss of energy

Solution Approach 1:

The patent uses a relatively low iron oxide content (0.3-0.8% by weight) which produces a subtle green tint that is aesthetically pleasing and not obviously colored. This parameter choice balances aesthetic requirements with solar control performance. The green tint provides sufficient solar absorption to keep total energy transmission below 60% while maintaining visual appeal that meets customer expectations for modern vehicle aesthetics.

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 configuration allows for a lighter weight glazing that meets energy transmission requirements and is suitable for use with optical sensors, such as LIDAR systems, while maintaining high visible light transmission and optimal solar control, suitable for installation as a windscreen.

Implementation Method 1

the first ply of glazing material being a pane of body-tinted glass having a colourant portion consisting of 0.70 to 1.0 % by weight total iron (calculated as Fe 2 O 3 )

Methodology Applied
Scientific EffectAbsorption (EM radiation): Absorption (EM radiation)

Implementation Method 2

0 to 1.0 % titania (calculated as TiO 2 ) and 0 to 2.0 % ceria (calculated as CeO 2 )

Methodology Applied
Scientific EffectAbsorption (EM radiation): Absorption (EM radiation)

Data Source

PatentEP2155487B1Tinted laminated vehicle glazing
Publication Date: 2020.09.16 PILKINGTON AUTOMOTIVE
  • EP2155487B1 patent drawingFigure 1
  • EP2155487B1 patent drawingFigure 2~3
  • EP2155487B1 patent drawingFigure 4

AI summary

A laminated vehicle glazing, suitable for use with an optical sensor (for example a LIDAR type sensor), comprises first and second plies of glazing material joined together by a ply of interlayer material between them, and either: a) the first ply is a pane of body-tinted glass having a colourant portion consisting of 0.70 to 1.00 % by weight total iron (calculated as Fe2O3), 0 to 1.0 % titania and 0 to 2.0 % ceria, such that the glazing has a transmittance of at least 30 % in the wavelength range 400 to 2100 nm, or b) the first ply of glazing material is a pane of body-tinted glass having a colourant portion consisting of 0.30 to 0.80 by weight total iron (calculated as Fe2O3), 0 to 1.0 % titania (calculated as TiO2) and 0 to 2.0 % ceria (calculated as CeO2), and the ply of interlayer material is a solar (IR) absorbing material, such that the glazing has a transmittance of at least 30 % in the wavelength range 750 to 1300 nm.