Laminated Vehicle Glazing for High NIR LIDAR Transmission

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Solution Overview

Problem

Current laminated glazing systems for vehicles, particularly those incorporating LIDAR technology, face challenges in achieving high near-infrared transmission while maintaining comfort, aesthetics, and cost-effectiveness, especially when using two full extra-clear glasses.

Innovation Solution

A laminated glazing system comprising a first sheet of glass with reduced iron oxide content and an anti-reflective coating, combined with a second sheet of glass having a higher iron oxide content, and a hollowed-out lamination interlayer to enhance transmission in the near-infrared range, optimizing the placement of the anti-reflective coating for improved performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If two full extra-clear glass sheets are used to achieve high near-infrared transmission, then LIDAR performance is improved, but cost increases and aesthetics deteriorate

Engineering Contradiction:
ImproveLIDAR performanceVSAvoidcost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent applies different iron oxide content levels to different glass sheets: the first sheet (exterior) has low iron oxide content (0.002-0.06%) for high NIR transmission, while the second sheet (interior) has higher iron oxide content (0.06-1.5%) for aesthetic appearance. This local differentiation allows each sheet to perform its specific function optimally without requiring both sheets to be expensive extra-clear glass.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent creates a composite glazing system combining glass sheets with different compositions (different iron oxide contents) and an interlayer with specific optical properties. This composite structure achieves high overall NIR transmission while maintaining aesthetic appearance, replacing the need for two identical extra-clear glass sheets.

Inventive Principle:
Principle #40Composite materials

2Reliability

If two full extra-clear glass sheets are used to achieve high near-infrared transmission, then LIDAR performance is improved, but the appearance and comfort deteriorate

Engineering Contradiction:
ImproveLIDAR performanceVSAvoidaesthetics and comfort
Core Design Contradiction:
ReliabilityVSIllumination intensity

Solution Approach 1:

The patent assigns different optical properties to different sheets: the first sheet optimizes for NIR transmission (low iron oxide) while the second sheet optimizes for visible light appearance (higher iron oxide giving green/blue tint). This local quality differentiation resolves the contradiction between LIDAR performance and aesthetic comfort.

Inventive Principle:
Principle #3Local quality

3Reliability

If the anti-reflective coating is placed on the first sheet of glass, then near-infrared transmission is improved, but the coating needs access to the free surface

Engineering Contradiction:
Improvenear-infrared transmissionVSAvoidcoating accessibility
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent segments the glazing system into distinct functional layers, creating a through-hole in the interlayer that provides direct access to the free surface of the first glass sheet. This allows the anti-reflective coating to be applied directly to the exterior surface without interference from intermediate layers, simplifying the coating application process.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The interlayer acts as an intermediary element that can be selectively removed (via through-hole) to provide access to the glass surface. This mediator approach allows the AR coating to reach the first sheet's free surface while the interlayer remains in place to provide lamination and structural functions.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Reliability

If the iron oxide content in the first sheet is reduced to increase transmission, then near-infrared performance is improved, but the glass becomes more vulnerable to degradation

Engineering Contradiction:
Improvenear-infrared transmissionVSAvoidglass durability
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent uses low iron oxide content (0.002-0.06%) specifically in the first sheet where high NIR transmission is critical, while the second sheet has higher iron oxide content (0.06-1.5%) that provides both aesthetic appearance and enhanced durability. This local differentiation allows the first sheet to be optimized for optical performance without compromising overall system durability.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The composite glazing system combines glass sheets with different compositions, where the second sheet with higher iron oxide content provides structural robustness and resistance to degradation, compensating for the more vulnerable first sheet with lower iron oxide content optimized for NIR transmission.

Inventive Principle:
Principle #40Composite materials

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 achieves higher transmission levels in the near-infrared range, improves comfort and aesthetics, and reduces costs by eliminating the need for a second extra-clear glass, while maintaining effective performance for LIDAR applications.

Implementation Method 1

The first sheet of glass comprises, on the face F2, an anti-reflective coating, preferably local, at at least one so-called working wavelength in the infrared in a range from 800nm to 1800nm

Methodology Applied
Scientific EffectAnti-reflective coating: Anti-Reflective Coating

Implementation Method 2

The second sheet of glass... has a weight content of total iron oxide of at least 0.4% and preferably of at most 1.5%

Methodology Applied
Scientific EffectAbsorption: Absorption (EM radiation)

Data Source

PatentEP4031367B1Laminated vehicle glazing and related apparatus with near infrared vision system
Publication Date: 2023.11.08 SAINT GOBAIN VITRAGE SA
  • EP4031367B1 patent drawingFigure 1
  • EP4031367B1 patent drawingFigure 2
  • EP4031367B1 patent drawingFigure 3

AI summary

The invention relates to a laminated vehicle glazing (100) comprising a first extra-clear glass sheet (outer glazing), a lamination interlayer and a second glass sheet (inner glazing) having a hole passing through the latter.