Vehicle Windscreen Optical Filter Adhesion

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Solution Overview

Problem

Modern vehicle sensors, such as rain sensors, are affected by interfering radiation components like visible light and ultraviolet radiation, leading to reduced sensitivity, and existing solutions like separate optical filters cause reflection losses and manufacturing issues with laminated panes.

Innovation Solution

A vehicle window with an optical filter attached to the interior surface via an adhesive layer, where the filter's area is less than 20% of the pane, designed as a daylight filter with specific transmission characteristics, using a plastic film with absorbent materials or coatings, and an optically clear adhesive to minimize reflection and manufacturing defects.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a separate optical filter is positioned in the housing for the sensor, then the sensor sensitivity is improved by filtering out interfering radiation, but reflection losses occur on the filter surfaces which reduces sensor efficiency

Engineering Contradiction:
Improvesensor sensitivityVSAvoidreflection losses
Core Design Contradiction:
Measurement precisionVSLoss of energy

Solution Approach 1:

The optical filter is merged with the pane structure by attaching it directly to the interior surface of the pane using an adhesive layer. This integration eliminates the separate air-filter transition interface, thereby removing the reflection losses that would occur at such interfaces while maintaining the filter's function of blocking interfering radiation components.

Inventive Principle:
Principle #5Merging (Combining)

2Loss of energy

If an optical filter is laminated into the thermoplastic intermediate layer of a laminated pane, then reflection losses are avoided, but warping of the intermediate layer occurs during production

Engineering Contradiction:
Improvereflection lossesVSAvoidwarping of intermediate layer
Core Design Contradiction:
Loss of energyVSManufacturing precision

Solution Approach 1:

The filter integration process is segmented into two independent stages: first, the laminated pane is produced without the filter; second, the optical filter is attached to the completed pane's interior surface using an adhesive layer. This segmentation prevents the filter from interfering with the lamination process, avoiding warping of the intermediate layer while still achieving the benefit of eliminated reflection losses at air-filter interfaces.

Inventive Principle:
Principle #1Segmentation

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 solution enhances sensor sensitivity by filtering out interfering radiation while avoiding reflection losses and manufacturing issues, applicable to both tempered and laminated glass, and is easier to produce with reduced warping risks.

Implementation Method 1

the optical filter is a daylight filter and wherein the layer of adhesive has an absorption in the visible spectral range of less than 5%

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

Implementation Method 2

an optical filter which is connected to the interior surface of the pane via at least one layer of an adhesive

Methodology Applied
Scientific EffectAdhesion: Adhesive

Data Source

PatentEP2796288B1Vehicle pane with an optical filter
Publication Date: 2018.06.27 SAINT GOBAIN VITRAGE SA
  • EP2796288B1 patent drawingFigure 1~2
  • EP2796288B1 patent drawingFigure 3~4

AI summary

The present invention relates to a vehicle windscreen with an optical filter, comprising at least: - a windscreen (1) and - an optical filter (2) which is connected to the interior surface (I) of the windscreen (1) via at least one layer of an adhesive (3), wherein the area of ​​the optical filter (2) is less than 20% of the area of ​​the windscreen (1) and wherein the optical filter (2) is arranged in the beam path of a transmitter or receiver (6) of electromagnetic radiation arranged on the interior side of the windscreen (1).