Autocollimation Optoelectronic Sensor for Specular Surface Detection

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Solution Overview

Problem

Existing optoelectronic sensor systems face challenges in reliably detecting and evaluating specularly reflected light, especially due to variations in object angle and distance, which affects the accuracy of surface property characterization.

Innovation Solution

The optoelectronic sensor system employs an image sensor and a lens arrangement that generates a scattering angle-dependent light distribution, allowing for improved detection of specularly reflected light by encoding information about the scattering angle in the two-dimensional intensity profile, and includes an evaluation unit to quantify surface characteristics and correct for object-angle-dependent changes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the transmitted light path and received light path are arranged in autocollimation configuration, then the influence of object angle and distance on specular signal intensity is reduced, but the system complexity increases due to additional optical components

Engineering Contradiction:
Improvedetection reliabilityVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the transmitted light path and received light path into a single optical axis, merging two separate optical paths into one. This autocollimation configuration allows the same optical components to serve both transmission and reception functions, reducing the number of separate components while maintaining detection reliability.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The optical components in the transmitted light path are designed to also function for receiving reflected light. The same lens and optical path are used for both emitting transmitted light and collecting specularly reflected light, making the system multi-functional and reducing overall complexity.

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

2Loss of information

If conventional light receivers are used without image sensor, then the device complexity is lower, but the ability to detect and evaluate scattering angle information is insufficient

Engineering Contradiction:
Improvescattering angle informationVSAvoidreceiver complexity
Core Design Contradiction:
Loss of informationVSDevice complexity

Solution Approach 1:

The patent transitions from a single-point light receiver to a two-dimensional image sensor array. This dimensional expansion allows the system to capture spatial distribution of reflected light, encoding scattering angle information in the spatial coordinates of the sensor array, thereby preserving angular information that would be lost with conventional receivers.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Measurement precision

If multiple reception channels are provided for gloss and remission detection, then the measurement precision is improved, but the device complexity increases

Engineering Contradiction:
Improvesurface property characterization precisionVSAvoidoptical path complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent merges the gloss channel and remission channel into a single autocollimation optical path. By using the same transmitted light path for both measurement purposes and processing the two-dimensional light distribution pattern, the system achieves multiple measurement capabilities without requiring separate optical paths, thus reducing complexity while maintaining precision.

Inventive Principle:
Principle #5Merging (Combining)

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 enhances the detection of specularly reflected light, reduces the impact of object angle and distance variations, and enables reliable characterization of surface properties, including gloss and anisotropic structures, even for objects at varying distances.

Implementation Method 1

This is usually done using a beam splitter, preferably using a splitter mirror.

Methodology Applied
Scientific EffectBeam splitting: Reflection

Implementation Method 2

a lens arrangement

Methodology Applied
Scientific EffectLight refraction and focusing: Lens

Implementation Method 3

a light transmitter for emitting transmitted light along a transmitted light path into the monitored area

Methodology Applied
Scientific EffectLight emission: Light

Implementation Method 4

a light receiver for receiving received light from the monitored area, which is emitted by an object to be detected

Methodology Applied
Scientific EffectLight detection: Photoelectric Effect

Data Source

PatentEP3751256B1Optoelectronic sensor system for detecting objects in a surveillance range
Publication Date: 2023.05.31 SICK AG
  • EP3751256B1 patent drawingFigure 1
  • EP3751256B1 patent drawingFigure 2
  • EP3751256B1 patent drawingFigure 3

AI summary

The present invention relates to an optoelectronic sensor system for detecting objects in a monitoring area, comprising a light transmitter for emitting transmitted light along a transmitted light path into the monitoring area, a light receiver for receiving received light from the monitoring area, which is diffusely and/or specularly reflected by a detectable object in the monitoring area towards the light receiver, wherein the transmitted light path and the received light path coincide at least partially according to the autocollimation principle, and a lens arrangement. According to the invention, the light receiver is designed as an image sensor, and the lens arrangement is configured such that the intensity profile of a two-dimensional received light distribution generated by the lens arrangement on the light receiver includes information about the scattering angle relative to a surface of a detected object.