Optoelectronic Sensor Pulse Timing for Interference Reduction

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Solution Overview

Problem

Optoelectronic sensors face interference from other sensors and environmental sources due to similar frequency patterns, leading to faulty signal interpretation and superposition of useful signals with disturbances at fixed time intervals.

Innovation Solution

The method involves emitting light pulses in repetitive patterns with varying pause lengths, where each pause length is between 60% to 150% of the arithmetic mean, and using prime number ratios for pulse/pause ratios to reduce interference, allowing for multiple evaluations to detect interference pulses and switch between operating states based on signal intensity thresholds.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If light pulses are emitted at a predefined frequency, then the sensor can operate with stable timing, but interference signals from other sensors and environmental sources cannot be distinguished from useful signals

Engineering Contradiction:
Improvesignal distinction accuracyVSAvoidinterference from other sensors and environmental sources
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies dynamics by making the pause lengths between light pulses variable rather than constant. Each pause length Li is selected from a set of different pause lengths, creating a dynamic, non-repeating pattern that prevents synchronization with interference sources while maintaining operational reliability.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the temporal parameters of the light pulse sequence by varying pause lengths according to the formula Li = (100 + ai) * (T/10), where ai are different integers. This parameter variation creates unique pulse patterns that distinguish useful signals from interference while maintaining energy efficiency through controlled averaging.

Inventive Principle:
Principle #35Parameter changes

2Object-affected harmful factors

If statistical variation in cycle times is incorporated to reduce mutual interference, then interference between sensors is reduced, but component tolerances make this variation unavoidable and unpredictable

Engineering Contradiction:
Improvemutual interference between sensorsVSAvoidunpredictable variation due to component tolerances
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent intentionally introduces controlled dynamics through a predetermined sequence of different pause lengths. This controlled variation actively reduces interference between multiple sensors while eliminating the unpredictability caused by component tolerances, as the variation pattern is deliberately designed rather than randomly occurring.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent uses periodic action by implementing a repeating pattern of varied pause lengths. The sequence of different pause lengths is repeated in a controlled manner, creating a periodic structure that prevents synchronization with other sensors while maintaining systematic predictability for signal processing.

Inventive Principle:
Principle #19Periodic action

3Use of energy by moving object

If light pulses are emitted with constant pause length, then energy consumption is minimized and operation is simple, but interference signals with fixed time intervals cannot be distinguished from useful signals

Engineering Contradiction:
Improveenergy consumptionVSAvoidinterference detection capability
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The patent introduces dynamics by varying pause lengths within controlled limits. The pause lengths Li satisfy the condition that their arithmetic mean equals T/10, ensuring that the overall energy consumption remains comparable to constant-frequency operation while gaining the ability to distinguish interference signals through pattern recognition.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes temporal parameters by using different pause lengths Li = (100 + ai) * (T/10) while maintaining their arithmetic mean at T/10. This parameter variation enables interference detection through multiple evaluation of successive light pulses while keeping energy consumption comparable to constant-frequency operation.

Inventive Principle:
Principle #35Parameter changes

4Reliability

If the pause length is varied to detect interference, then interference pulses can be detected through multiple evaluation, but the complexity of the evaluation strategy increases

Engineering Contradiction:
Improveinterference pulse detectionVSAvoidevaluation strategy complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies feedback by using the received signal strength information to control the emission of subsequent light pulses. The evaluation device compares received signals against expected patterns, and this feedback mechanism enables interference detection while keeping the control logic relatively simple through threshold-based decision making.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent uses periodic action by implementing systematic multiple evaluation of successive light pulses. The evaluation occurs at regular intervals corresponding to the pattern of varied pause lengths, providing a structured approach to interference detection that reduces evaluation complexity through methodical repetition.

Inventive Principle:
Principle #19Periodic action

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 approach effectively reduces interference between optoelectronic sensors and environmental sources, maintaining energy efficiency and minimal adaptation of evaluation strategies, while preventing synchronous operation and minimizing measurement disruption.

Implementation Method 1

a transmitter (2) emits light pulses (L1, L2, L3, L4, L5, L6, L7)

Methodology Applied
Scientific EffectLight: Light

Implementation Method 2

at least one receiver (5) receives light signals (S1, S2, S3, S4, S5, S6, S7, SI)

Methodology Applied
Scientific EffectPhotoelectric Effect: Photoelectric Effect

Data Source

PatentEP2983009B1Operation of an optoelectronic sensor using a method for emitting light pulses
Publication Date: 2020.12.09 BALLUFF
  • EP2983009B1 patent drawingFigure 1~2

AI summary

The invention relates, in a first aspect, to a method for emitting light pulses, in which the light pulses are emitted in repeating patterns of at least three light pulses. All pause lengths between the light pulses of a pattern, or all cycle lengths of a pattern, are different. Each pause length or cycle length is in the range of 60% to 150% of the arithmetic mean of all pause lengths or cycle lengths of a pattern. Furthermore, the invention relates, in a second aspect, to a method for operating an optoelectronic sensor comprising at least one transmitter and at least one receiver. In an operating state of the optoelectronic sensor, the transmitter emits light pulses by means of a method according to the first aspect of the invention.