Optoelectronic Sensor Carrier Recesses Reduce Scattered Light

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Solution Overview

Problem

Existing optoelectronic sensors face issues with incorrect distance measurements due to the influence of disturbing scattered light from the environment, which can cause objects to be misidentified as background or vice versa.

Innovation Solution

The optoelectronic sensor features a carrier with recesses or openings around the transmitter to reduce scattered light, specifically designed to eliminate critical areas that contribute to this issue, thereby minimizing the impact of stray light on the measurement focus.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If the transmitter illuminates the immediate surroundings, then the background and object are illuminated for detection, but scattered light from the transmitter environment causes incorrect distance measurements and object misidentification

Engineering Contradiction:
Improveillumination of background and objectVSAvoiddistance measurement accuracy
Core Design Contradiction:
Illumination intensityVSMeasurement precision

Solution Approach 1:

The patent extracts and removes the problematic scattered light from the measurement path by introducing a mask element that blocks light from the transmitter's immediate surroundings from reaching the receiver, while preserving the useful illumination of the background and object

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The mask element acts as an intermediary component positioned between the transmitter and receiver, selectively blocking harmful scattered light paths while allowing the useful light paths from the background and object to reach the receiver

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If blackening or lateral closure of the transmitter environment is used, then scattered light is reduced, but device complexity and manufacturing difficulty increase

Engineering Contradiction:
Improvereduction of scattered light effectVSAvoidstructural complexity of transmitter assembly
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

Instead of uniformly blackening or enclosing the entire transmitter environment, the patent applies a mask element with specific local geometry that targets only the critical scattered light paths, achieving the desired effect with minimal structural addition

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent changes the geometric parameters of the mask element (position, size, shape) to optimize the blocking of scattered light while minimizing the impact on the overall device structure and manufacturing complexity

Inventive Principle:
Principle #35Parameter changes

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 significantly reduces the effect of scattered light, preventing incorrect object or background identification and ensuring accurate distance measurements by eliminating sources of interference near the transmitter.

Implementation Method 1

a transmitter for emitting a transmitted light beam into the monitored area, a receiver for detecting a received light beam from the monitored area, the received light beam depending on a distance of the object to be detected from the optoelectronic sensor assumes a variable beam angle relative to the transmitted light beam

Methodology Applied
Scientific EffectLight reflection: Reflection

Implementation Method 2

the position of the image is usually defined by the center of intensity in the image

Methodology Applied
Scientific EffectTriangulation:

Data Source

PatentEP2053417B1Optoelectronic sensor for detecting objects in a surveillance range
Publication Date: 2011.04.27 PEPPERL & FUCHS GMBH
  • EP2053417B1 patent drawingFigure 1
  • EP2053417B1 patent drawingFigure 2~3
  • EP2053417B1 patent drawingFigure 4~5

AI summary

The sensor (100) has a transmitter (20) for transmission of transmission light bundles (22) into a monitoring area (40), and a receiver (30) for detection of reception light bundles (38, 39). A control and evaluation unit (50) is provided for processing of measurement data of the receiver and for outputting a switching signal when an object (44) is detected in the monitoring area. The transmitter is arranged on a carrier, where the carrier is provided with a recess for reduction of scattered light from an environment of the transmitter.