Laminated Vehicle Glazing for Near-Infrared LIDAR Separation

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Solution Overview

Problem

Current laminated glazing solutions for vehicles, particularly those incorporating LIDAR systems, face challenges in optimizing near-infrared transmission and comfort while maintaining mechanical strength and aesthetics, often requiring two full extra-clear glasses which are inefficient and costly.

Innovation Solution

A laminated glazing design featuring a first sheet of glass with low near-infrared absorption and a second sheet with higher iron oxide content, incorporating two through holes to separate the emitting and receiving parts of the infrared vision system, reducing parasitic radiation and allowing for more design flexibility, and using a thinner lamination interlayer for improved comfort and economy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If two full extra-clear glass sheets are used for LIDAR integration, then near-infrared transmission is improved, but manufacturing cost and weight increase

Engineering Contradiction:
Improvenear-infrared transmissionVSAvoidglass material quantity
Core Design Contradiction:
Illumination intensityVSQuantity of substance

Solution Approach 1:

The patent applies local quality by differentiating the iron oxide content between the two glass sheets. The first glass sheet has low iron oxide content (≤0.05%) for high near-infrared transmission where the LIDAR beam passes through, while the second glass sheet has higher iron oxide content (0.4-1.5%) for aesthetic appearance and solar control. This localized optimization allows using thinner glass overall while maintaining both optical performance and appearance requirements.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent creates a composite glazing structure combining two glass sheets with different compositions (different iron oxide contents) and a lamination interlayer. This composite approach allows each layer to perform its specific function optimally - the first sheet for infrared transmission and the second for aesthetics - while the assembly provides both high near-infrared transmission and reduced overall material quantity compared to using two full extra-clear sheets.

Inventive Principle:
Principle #40Composite materials

2Strength

If a thicker lamination interlayer is used, then mechanical strength is improved, but vehicle comfort and aesthetics deteriorate

Engineering Contradiction:
Improvemechanical strengthVSAvoidvehicle comfort
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

The patent changes the thickness parameter of the lamination interlayer from conventional values (typically 1.52mm or 2.28mm) to a thinner range (0.76mm to 1.52mm). This parameter reduction improves vehicle comfort by reducing the risk of head injury in impact scenarios and enhances aesthetics by reducing the visible thickness and distortion. The mechanical strength requirement is maintained through the optimized glass sheet configuration and the specific iron oxide content differentiation between sheets.

Inventive Principle:
Principle #35Parameter changes

3Object-generated harmful factors

If through holes are added to separate emitting and receiving parts, then parasitic radiation is reduced, but manufacturing complexity increases

Engineering Contradiction:
Improveparasitic radiationVSAvoidmanufacturing complexity
Core Design Contradiction:
Object-generated harmful factorsVSEase of manufacture

Solution Approach 1:

The patent applies segmentation by introducing through holes in the second glass sheet to separate the LIDAR emitting and receiving paths. The emitter is positioned behind the glazing while the receiver is positioned in the vehicle interior, with the through holes providing dedicated optical paths. This segmentation eliminates parasitic radiation by preventing cross-contamination between emitted and received infrared beams, improving LIDAR measurement precision. The manufacturing complexity is managed by positioning the holes in standard locations that can be integrated into the existing glazing production process.

Inventive Principle:
Principle #1Segmentation

4Ease of manufacture

If the second glass sheet has higher iron oxide content, then aesthetics and solar control are improved, but near-infrared transmission deteriorates

Engineering Contradiction:
ImproveaestheticsVSAvoidnear-infrared transmission
Core Design Contradiction:
Ease of manufactureVSIllumination intensity

Solution Approach 1:

The patent applies local quality by strategically placing the higher iron oxide content (0.4-1.5%) specifically in the second glass sheet that is visible from the vehicle interior, while keeping the first glass sheet (exposed to LIDAR beams) with low iron oxide content (≤0.05%). This localized composition differentiation allows the second sheet to provide aesthetic appearance and solar control functions while the first sheet maintains high near-infrared transmission for LIDAR operation. The lamination interlayer with its specific thickness range (0.76mm to 1.52mm) further optimizes the overall optical performance by balancing transmission and aesthetic requirements.

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 design enhances the performance of the LIDAR system by improving near-infrared transmission, reducing parasitic radiation, and providing better mechanical strength and comfort, while being more economical and aesthetically pleasing compared to traditional solutions.

Implementation Method 1

a first sheet of glass, in particular curved, intended to be the exterior glazing, with a first main external face F1 and a second main internal face F2 facing the passenger compartment... The first glass sheet... has a weight content of total iron oxide (expressed in the form Fe2O3) of at most 0.05% (500 ppm), preferably at most 0.03% (300 ppm) and at most 0.015% (150 ppm)

Methodology Applied
Scientific EffectNear-infrared transmission: Absorption (EM radiation)

Implementation Method 2

The second glass sheet... has a weight content of total iron oxide (expressed in the form Fe2O3) of at least 0.4% and preferably at most 1.5%... a second through hole, in the thickness of the second sheet of glass, separate from the first through hole... reducing parasitic radiation

Methodology Applied
Scientific EffectIron oxide absorption: Absorption (EM radiation)

Implementation Method 3

a lamination interlayer (mono or multi-layer), possibly neutral, clear, extra-clear or tinted, in particular gray or green, made of polymer material, preferably thermoplastic and better still made of polyvinyl butyral (PVB preferably including plasticizers)

Methodology Applied
Scientific EffectLamination: Lamination

Data Source

PatentEP4255726B1Laminated vehicle glazing and device comprising an associated near-infrared vision system
Publication Date: 2024.07.31 SAINT GOBAIN SEKURIT FRANCE
  • EP4255726B1 patent drawingFigure 1
  • EP4255726B1 patent drawingFigure 2
  • EP4255726B1 patent drawingFigure 3

AI summary

The invention relates to laminated vehicle glazing (100) comprising a first extra-clear glass sheet (outer glazing), a lamination interlayer, and a second glass sheet (inner glazing) with two through-holes extending through the second sheet. The invention also relates to such a glazing with an infrared vision system.