Optoelectronic Sensor Position Detection Using Time-of-Flight Segmentation

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Solution Overview

Problem

Current position detection methods, such as camera systems and distance sensors, are expensive, time-consuming, and prone to errors due to the complexity of 2D and 3D image acquisition, and existing optoelectronic sensors like SPADs are unsuitable for precise positioning due to their sensitivity to interference and complexity in evaluation.

Innovation Solution

An optoelectronic sensor with a light emitter and a matrix of light receiving elements, where specific active sub-areas are configured for position detection, allowing for time-of-flight determination of distance values from different object areas, processed in a control unit to achieve precise positioning with reduced complexity and cost.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If camera systems are used for positioning, then positioning accuracy can be achieved, but the system becomes expensive and complex

Engineering Contradiction:
Improvepositioning accuracyVSAvoidsystem complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts only the essential distance measurement capability from the complex camera system, using a simple time-of-flight sensor array instead of full image processing. This selective extraction achieves positioning accuracy without the complexity of camera systems.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the mechanical/optical image processing system with an electronic time-of-flight measurement system. By substituting the complex optical-mechanical camera system with electronic distance sensing, positioning accuracy is maintained while system complexity is reduced.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If 3D camera systems are used for positioning, then depth information is provided, but the system becomes oversized and slow

Engineering Contradiction:
Improvedepth measurement accuracyVSAvoidprocessing speed
Core Design Contradiction:
Measurement precisionVSSpeed

Solution Approach 1:

The patent extracts only the distance measurement function from 3D camera systems, eliminating the need for complex 3D image processing. By using a simplified time-of-flight sensor array, depth information is obtained at much higher speeds.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent segments the detection area into multiple independent time-of-flight measurement zones, allowing parallel processing of distance measurements across different spatial regions. This segmentation enables fast processing while maintaining depth measurement accuracy.

Inventive Principle:
Principle #1Segmentation

3Measurement precision

If SPADs are used for distance measurement, then sensitivity is improved, but interference events generate false signals

Engineering Contradiction:
Improvelight detection sensitivityVSAvoidsignal accuracy
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent segments the SPAD array into multiple independently evaluated groups, allowing statistical differentiation between true signals and interference events. By analyzing multiple segments simultaneously, the system maintains high sensitivity while filtering out false signals through statistical evaluation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements feedback mechanisms where the evaluation circuit continuously monitors and compares signals from multiple SPAD groups, using statistical information to identify and reject interference events. This feedback loop maintains signal accuracy while preserving the high sensitivity of SPADs.

Inventive Principle:
Principle #23Feedback

4Reliability

If multiple SPADs are evaluated together to counteract interference, then signal reliability is improved, but the evaluation complexity increases

Engineering Contradiction:
Improvesignal accuracyVSAvoidevaluation complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the evaluation of multiple SPAD groups into a unified statistical processing framework. By combining the results from multiple segments through coordinated evaluation circuits, the system achieves improved reliability without proportionally increasing complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent designs the evaluation circuit to perform multiple functions: it processes signals from all SPAD groups simultaneously, applies statistical filtering, and generates position data. This multi-functionality reduces overall system complexity while maintaining high signal reliability.

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 simple, robust, and accurate position detection with a compact sensor system, capable of quasi-real-time evaluation and precise distance measurement, significantly reducing manufacturing costs and size compared to conventional camera systems.

Implementation Method 1

At least one light emitter (12) emits a modulated light signal (16), wherein the light signal (16) can be used for determining a light travel time

Methodology Applied
Scientific EffectLight emission and reflection: Light

Implementation Method 2

measure the light travel time of the light signal (16) and generate a corresponding distance value

Methodology Applied
Scientific EffectTime of flight: Time of Flight

Implementation Method 3

The incident light triggers a controlled avalanche breakdown (avalanche effect). This multiplies the charge carriers generated by the incident photons

Methodology Applied
Scientific EffectAvalanche breakdown: Avalanche Breakdown

Implementation Method 4

a single charge carrier released by a single photon can trigger an uncontrolled avalanche

Methodology Applied
Scientific EffectPhotoelectric effect: Photoelectric Effect

Data Source

PatentEP3454086B1Optoelectronic sensor and method for detecting the position of an object
Publication Date: 2020.01.29 SICK AG
  • EP3454086B1 patent drawingFigure 1~2
  • EP3454086B1 patent drawingFigure 3~4
  • EP3454086B1 patent drawingFigure 5~6

AI summary

An optoelectronic sensor (10) for position detection of an object (20) in a detection area (18) is specified, comprising a light transmitter (12) for emitting a light signal (16) into the detection area (18), a light receiver (26) with a plurality of light receiving elements (28) for detecting received light (22) from the detection area (18), several distance determination units (30) for determining a distance value to an area (50') of the object (20) from a light travel time between the emission of the light signal (16) and the reception of the light signal (22) remitted or reflected by the object (20), wherein the distance determination units (30) are each connected to individual or groups of light receiving elements (28), and a selection unit (32) configured to variably connect distance determination units (30) to light receiving elements (28).and includes a control and evaluation unit (34) for position detection of the object (20), which compares the distance values ​​with reference values ​​of an object position.