Impurity Detection Device Using Dual-Interface Light Scattering

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Solution Overview

Problem

Existing devices for detecting impurities on transparent surfaces, such as windshields and solar collectors, require high computational effort for image evaluation and are prone to intensity fluctuations due to light source degradation, making them costly and unreliable.

Innovation Solution

A device that generates both a reference signal and a measurement signal by scattering light from a transparent layer with a roughened or patterned surface, allowing for simple and cost-effective contamination detection by comparing these signals, while suppressing intensity fluctuations through simultaneous determination from the same light source.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If sensor arrays and complex image evaluation are used to detect contamination, then measurement precision is improved, but device complexity and computational effort increase

Engineering Contradiction:
Improvecontamination detection precisionVSAvoiddevice complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent segments the light beam path into two distinct functional sections: a reference path that reflects off the first surface to provide a stable reference signal, and a measurement path that transmits through the layer and reflects off the second surface to detect contamination. This segmentation allows simple signal comparison instead of complex image evaluation, reducing device complexity while maintaining detection precision.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The first surface of the transparent layer serves a dual function: it acts as both the optical interface for light entry and as the reference mirror for generating the reference signal. This self-service approach eliminates the need for separate reference components, simplifying the device structure while enabling reliable contamination detection through signal comparison.

Inventive Principle:
Principle #25Self-service

2Measurement precision

If stored reference images are used for comparison, then measurement precision is improved, but reliability deteriorates due to light source degradation and intensity fluctuations

Engineering Contradiction:
Improvecontamination detection precisionVSAvoiddetection reliability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent implements a dynamic reference signal generation system where the reference signal is continuously produced in real-time by reflecting light from the first surface, rather than relying on static stored reference images. This dynamic approach automatically adapts to light source intensity changes and degradation, maintaining reliable contamination detection without requiring reference image updates or complex calibration procedures.

Inventive Principle:
Principle #15Dynamics

3Measurement precision

If multiple light sources and receivers are used to detect contamination on both surfaces, then measurement precision is improved, but device complexity and cost increase

Engineering Contradiction:
Improvecontamination detection precisionVSAvoiddevice complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent makes the transparent layer itself multi-functional: it serves as both the optical element under inspection and the reference mirror for generating the reference signal. By utilizing the first surface of the layer for reference signal generation, the system eliminates the need for separate reference mirrors or additional light sources, reducing device complexity while maintaining the ability to detect contamination on both surfaces.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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

Enables reliable and cost-effective detection of contamination without complex image evaluations, effectively managing light source intensity variations and reducing device costs.

Implementation Method 1

the first interface is set up to scatter part of the impinging light beam

Methodology Applied
Scientific EffectLight scattering: Scattering

Implementation Method 2

part of a portion of the light beam scattered at the second interface impinges on a receiver and forms a measurement signal

Methodology Applied
Scientific EffectLight scattering: Scattering

Data Source

PatentEP2293044B1Device and method for detecting impurities
Publication Date: 2013.05.15 PEPPERL & FUCHS GMBH
  • EP2293044B1 patent drawingFigure 1~2
  • EP2293044B1 patent drawingFigure 3~4
  • EP2293044B1 patent drawingFigure 5

AI summary

Device for detecting impurities (90) comprising a light source (10) emitting a light beam (20) and an opaque layer (40) with a first interface (45) and a second interface (55), wherein the light beam (20) emitted by the light source (10) first strikes the first interface (45), and a portion of the light beam (92) scattered at the second interface (55) strikes a receiver (70) and forms a measurement signal, wherein the first interface (45) is configured (46) to scatter a portion of the incident light beam (47), and the portion of the light beam (47) scattered at the first interface (45) striking the receiver forms a reference signal, and the device is further configured to determine a measure of the impurity of the second interface from the comparison of the reference signal and the measurement signal.