Laminated Windscreen Roughened Regions for Faster Impact Breakage
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Solution Overview
Problem
Conventional laminated automotive windscreens do not adequately address the risk of serious pedestrian injuries during collisions, as they do not effectively break to reduce the impact force on pedestrians.
Innovation Solution
A laminated glazing design with a second sheet of glazing material featuring a treated region, such as a laser-etched or sandblasted area, to facilitate easier breakage upon impact, reducing the rigidity and enhancing pedestrian safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the windscreen is made with conventional smooth glass surfaces, then the structural strength and integrity are maintained, but the ability to break easily upon pedestrian impact is reduced
Solution Approach 1:
The patent applies local quality by creating treated regions with modified surface properties (rougher texture, different refractive index) in specific areas of the glass sheet. These localized treated regions have different optical and mechanical characteristics compared to the surrounding untreated glass, enabling them to initiate and propagate cracks more easily upon impact while the rest of the glass maintains its structural strength and integrity.
2Object-affected harmful factors
If the entire glass surface is treated to facilitate breakage, then pedestrian safety is improved, but the visual clarity and aesthetic appearance are compromised
Solution Approach 1:
The patent applies local quality by creating treated regions with modified surface properties (rougher texture, different refractive index) in specific areas of the glass sheet. These localized treated regions have different optical and mechanical characteristics compared to the surrounding untreated glass, enabling them to initiate and propagate cracks more easily upon impact while the rest of the glass maintains its structural strength and integrity.
Solution Approach 2:
The patent applies partial action by treating only specific regions of the glass surface rather than the entire surface. The treated regions are positioned and sized to provide adequate crack initiation capability for safety purposes, while leaving the majority of the glass surface untreated to preserve visual clarity and aesthetic appearance.
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 treated regions on the second sheet of glazing material enable the laminated glazing to break more quickly and reduce the time taken for the windscreen to shatter, thereby minimizing pedestrian injuries during collisions.
Implementation Method 1
the first treated region having been subjected to a roughening process such that prior to the roughening process the first treated region has a first surface roughness, and after the roughening process, the first treated region has a second surface roughness
Implementation Method 2
the roughening process comprises irradiating at least a portion of the first region to be treated with a laser to laser etch the second major surface of the second sheet of glazing material in the first treated region
Data Source
AI summary
A laminated glazing for a vehicle windscreen comprising first and second sheets of glazing material joined by a sheet of adhesive interlayer material is described. The laminated glazing has an outer facing surface and an inner facing surface comprising a first treated region that has been subjected to a roughening process such that before the roughening process the first treated region has a first surface roughness and after the roughening process the first treated region has a second surface roughness. The first treated region having the second surface roughness helps the laminated glazing break when subject to an impact on the outer facing surface. Use of a roughened region to reduce the time taken for a laminated glazing to break upon being impacted by an impactor is also described.