Vehicle Composite Pane Indentation for Controlled Impact Fracture

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Solution Overview

Problem

Existing vehicle composite panes, particularly windshields, do not adequately address the need for controllable fracture characteristics and improved impact protection, especially in regions prone to pedestrian head impacts, while maintaining stone impact resistance and transparency.

Innovation Solution

A method involving indentation to create defect areas in vehicle composite panes, specifically on the inner and/or outer glass surfaces, followed by bending and lamination with a thermoplastic intermediate layer to control fracture characteristics and enhance impact protection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of moving object

If thinner glass is used to reduce weight, then fuel and electricity savings are achieved, but mechanical load-bearing capacity and impact protection are reduced

Engineering Contradiction:

Improveweight of glass panesVSAvoidmechanical load-bearing capacity

Core Design Contradiction:

Weight of moving objectVSStrength

Solution Approach 1:

The patent applies local quality by creating defect areas only in specific regions of the glass pane where improved impact protection is needed (such as the lower region for pedestrian safety), rather than uniformly modifying the entire pane. This allows thinner glass to be used overall while maintaining strength in critical areas through controlled defect-induced early fracture.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent segments the glass pane into different functional regions: regions with defect areas for improved impact protection and regions without defect areas for maintaining structural strength and stone impact resistance. This segmentation allows optimization of different areas for different purposes.

Inventive Principle:

Principle #1Segmentation

2Reliability

If defect areas are introduced to improve fracture characteristics, then early fracture occurs reducing deceleration rate, but stone impact resistance may be compromised

Engineering Contradiction:

Improveimpact protection for pedestriansVSAvoidstone impact resistance

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent applies preliminary action by pre-introducing defect areas into the glass pane during manufacturing, so that in the event of a pedestrian impact, the glass will fracture in a controlled manner at predetermined locations. This preliminary preparation ensures that the glass breaks before it can cause severe injury to pedestrians' heads, while the bending step subsequently heals these defects to maintain stone impact resistance.

Inventive Principle:

Principle #10Preliminary action

3Manufacturing precision

If indentation is performed on curved panes, then defect areas can be introduced, but manufacturing complexity and difficulty increase

Engineering Contradiction:

Improvedefect area introductionVSAvoidpane processing difficulty

Core Design Contradiction:

Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent applies preliminary action by performing the indentation step while the glass pane is still in its planar state, before any bending or curving operations. This sequence is crucial because indenting flat glass is much easier and more precise than indenting curved glass. After indentation creates the defect areas, the pane is then bent to the desired curvature, and finally the defects are healed through thermal or chemical processes.

Inventive Principle:

Principle #10Preliminary action

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

The method enables targeted early fracture in specific regions, reducing the deceleration rate of impacting bodies, thereby enhancing pedestrian safety and compliance with mechanical standards without compromising stone impact resistance.

Implementation Method 1

Heating of the indented pane(s) during the bending process causes a partial healing of the defect areas created by indentation

Methodology Applied

Scientific EffectHeating: Heating

Implementation Method 2

The defect areas introduced by indentation lead to a targeted weakening of the outer pane and/or inner pane, which significantly influences the fracture characteristics of the vehicle composite pane in the first partial region

Methodology Applied

Scientific EffectFracture Mechanics: Fracture Mechanics

Data Source

PatentUS20250353282A1Method for producing a vehicle composite pane with improved impact protection

Publication Date: 2025.11.20 SAINT GOBAIN SEKURIT FRANCE

AI summary

A method for producing a vehicle composite pane with improved impact protection, wherein at least a) an outer pane and an inner pane are provided, b) in at least a first partial region defect areas are introduced into the outer pane and/or inner pane, c) the outer pane and the inner pane are bent congruently together, d) a thermoplastic intermediate layer is placed onto the outer pane or the inner pane, e) the layer stack is completed with the inner pane or outer pane, and f) the layer stack composed of at least the outer pane, thermoplastic intermediate layer and inner pane is laminated to form a windshield, wherein the defect areas are introduced into the outer pane and/or inner pane by means of indentation.