Light Curtain Beam Alignment Using Intensity Feedback Under Vibration

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Solution Overview

Problem

Existing light curtains lack effective methods for precise alignment and adjustment, particularly in environments with vibration, leading to potential nuisance tripping and reduced safety and efficiency.

Innovation Solution

A system and method for light curtain alignment using light intensity signals and vibration data to adjust and align beam transmitters and receivers, incorporating a light intensity receiver, transmitter, and trip transmitter to ensure proper beam alignment and account for vibration-induced intensity degradation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If light curtain operates in standard mode with fixed thresholds, then normal operation is maintained, but nuisance tripping occurs in vibrating environments

Engineering Contradiction:
Improvelight curtain operation reliabilityVSAvoidnuisance tripping
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent implements dynamic threshold adjustment by continuously monitoring beam intensities from multiple beam receivers and adapting the trip threshold based on real-time measurements. Instead of using a fixed threshold, the system calculates dynamic thresholds that accommodate vibration-induced intensity variations, thereby preventing nuisance tripping while maintaining reliable operation.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system employs feedback mechanisms by measuring the actual light intensities received by each beam receiver and using this information to adjust the trip threshold. The controller continuously monitors the beam intensities and modifies the threshold accordingly, creating a closed-loop control system that adapts to changing environmental conditions and prevents false tripping.

Inventive Principle:
Principle #23Feedback

2Device complexity

If light curtain uses fixed trip threshold, then simple control is maintained, but alignment precision deteriorates under vibration

Engineering Contradiction:
Improvecontrol system complexityVSAvoidbeam alignment precision
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The control system transitions from static to dynamic operation by continuously adjusting the trip threshold based on real-time beam intensity measurements. This dynamic adaptation allows the system to maintain precise alignment detection capability even under vibration, as the threshold automatically compensates for intensity variations caused by movement.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system performs preliminary measurements of beam intensities during installation and operation to establish baseline values. These preliminary measurements are used to initialize the dynamic threshold calculation, enabling the system to adapt quickly to the specific installation environment and achieve accurate alignment without requiring complex manual calibration procedures.

Inventive Principle:
Principle #10Preliminary action

3Device complexity

If light curtain operates without vibration compensation, then device simplicity is maintained, but alignment accuracy decreases

Engineering Contradiction:
Improvealignment system complexityVSAvoidbeam alignment accuracy
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The light curtain system performs self-alignment and self-compensation by automatically measuring its own beam intensities and adjusting its trip threshold accordingly. The system uses its operational data to identify alignment issues and compensate for vibration effects without requiring external calibration equipment or complex additional components, thereby maintaining simplicity while improving accuracy.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system incorporates feedback loops that monitor beam intensities and use this information to automatically adjust alignment parameters and trip thresholds. This feedback mechanism enables the system to compensate for vibration-induced misalignment and intensity variations, maintaining high alignment accuracy without requiring complex external intervention or manual adjustment.

Inventive Principle:
Principle #23Feedback

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

Enhances the alignment process by providing real-time light intensity feedback and vibration compensation, reducing nuisance tripping and improving safety and operational reliability of light curtains.

Implementation Method 1

Each beam transmitter is configured to transmit a narrow beam of light

Methodology Applied
Scientific EffectLight emission: Light Emitting Diode

Implementation Method 2

Each beam receiver is configured to receive light from a corresponding beam transmitter of the plurality of beam transmitters

Methodology Applied
Scientific EffectPhotoelectric conversion: Photoelectric Effect

Data Source

PatentEP4036613B1Light curtain alignment using beam intensities
Publication Date: 2025.08.20 ROCKWELL AUTOMATION TECH INC
  • EP4036613B1 patent drawingFigure 1
  • EP4036613B1 patent drawingFigure 2
  • EP4036613B1 patent drawingFigure 3~4

AI summary

A component for light curtain alignment includes a light intensity receiver that receives a plurality of light intensity signals from beam receivers of a receiver unit of a light curtain. The light curtain includes a transmitter unit with beam transmitters arranged linearly on the transmitter unit. The light curtain includes the receiver unit with the plurality of beam receivers arranged linearly. Each beam receiver is configured to receive light from a corresponding beam transmitter. The component includes a light intensity transmitter configured to transmit, from the light curtain, the plurality of light intensity signals received by the light intensity receiver, where each light intensity signal is from one or more beam receivers, and a trip transmitter that transmits a trip signal in response to determining that a light intensity signal from a beam receiver of the plurality of beam receivers is below a trip threshold.