Opening Light Curtain Monitoring for Variable Object Orientation

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Solution Overview

Problem

Existing monitoring devices require prior alignment or training of objects to pass through light curtains, and they fail to reliably detect objects of varying sizes and orientations, posing a risk of unauthorized entry into hazardous areas.

Innovation Solution

A monitoring device using a light curtain with orthogonal light beams and an object recognition system that generates a matrix of expected signal sequences, combined with a control unit to compare and generate a shutdown signal based on a single Boolean signal, allowing detection of objects of any size and orientation without safety-critical data transmission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a light curtain with fixed alignment is used to monitor the opening, then the device complexity is reduced, but the adaptability to objects of varying sizes and orientations deteriorates

Engineering Contradiction:
Improvedevice complexityVSAvoidadaptability
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent applies dynamics by making the light curtain rotatable about its own axis, allowing the light beams to be oriented at different angles relative to the transport plane. This dynamic adjustment enables the system to adapt to objects of varying sizes and orientations without requiring multiple fixed light curtains, thus resolving the contradiction between device complexity and adaptability.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the angular parameter of the light beams by rotating the light curtain to different orientations. This parameter change allows the same light curtain to effectively monitor different object types and sizes, improving adaptability while maintaining a single device structure.

Inventive Principle:
Principle #35Parameter changes

2Difficulty of detecting and measuring

If the light beams run parallel to the transport plane, then the detection of objects is simplified, but the detection precision of objects with varying orientations deteriorates

Engineering Contradiction:
Improvedetection difficultyVSAvoiddetection precision
Core Design Contradiction:
Difficulty of detecting and measuringVSMeasurement precision

Solution Approach 1:

The light curtain can dynamically change its orientation from parallel to orthogonal (or at least at an angle) to the transport plane, allowing it to adapt to different object orientations. This dynamic adjustment maintains detection simplicity while improving detection precision for various object types.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent introduces angular orientation as an additional degree of freedom for the light curtain, allowing it to detect objects not only in the horizontal plane but also at different angular positions, thereby improving detection precision without significantly increasing detection complexity.

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

3Adaptability or versatility

If the light curtain is arranged to detect objects of any orientation, then the adaptability is improved, but the device complexity increases due to additional scanning and control mechanisms

Engineering Contradiction:
ImproveadaptabilityVSAvoiddevice complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent combines the light curtain with a scanning mechanism and control unit into an integrated system. The scanning means and control unit merge the functions of multiple light curtains into a single rotatable device, reducing overall system complexity while maintaining high adaptability.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The single light curtain serves multiple functions by rotating to different orientations, effectively replacing what would otherwise require multiple fixed light curtains. This multi-functionality reduces device complexity while maintaining adaptability to various object types and orientations.

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

4Loss of energy

If a single Boolean signal is transmitted for safety, then the data transmission load is reduced, but the ability to transmit detailed object information deteriorates

Engineering Contradiction:
Improvedata transmission loadVSAvoidobject information
Core Design Contradiction:
Loss of energyVSLoss of information

Solution Approach 1:

The patent extracts only the critical safety-relevant information (presence/absence of object, basic geometric properties) and transmits it as a single Boolean signal or minimal data set. Non-critical detailed information is processed locally or not transmitted at all, reducing data transmission load while maintaining safety functionality.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The system transmits only the necessary portion of object information required for safety decisions, rather than transmitting complete detailed data. This partial transmission approach reduces energy consumption and data load while sufficient for safety purposes.

Inventive Principle:
Principle #16Partial or excessive 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

Ensures reliable detection of objects with varying dimensions and orientations, reducing the risk of unauthorized entry by triggering a safe response only when deviations are detected, thus minimizing safety-related data transmission and system load.

Implementation Method 1

a light curtain, a transmitter arrangement with several light-beam emitting transmitters, and a receiver arrangement with several light-beam receiving receivers which detect an interruption of a light beam

Methodology Applied
Scientific EffectLight beam interruption detection: Photoelectric Effect

Data Source

PatentEP4345512B1Monitoring device and method for monitoring an opening
Publication Date: 2025.10.29 SIEMENS AG
  • EP4345512B1 patent drawingFigure 1
  • EP4345512B1 patent drawingFigure 2
  • EP4345512B1 patent drawingFigure 3

AI summary

To monitor an opening (2) through which objects (O1, O2, O3) are introduced by means of a transport means (TM), a monitoring device (100) comprising: - a light curtain (1), comprising: - a transmitter arrangement (S) with several light-beam emitting transmitters (S1, ..., S11) and - a receiver arrangement (E) with several light-beam receiving receivers (E1, ..., E11) which detect an interruption of a light beam and provide a signal (U), - wherein the light curtain (1) is arranged at the opening (2) such that the light beams are orthogonal to a transport plane (TE) of the transport means (TM), further comprising: - a scanning means configured to detect the signals (U) of the receivers (E1, ...,E11) of the light curtain (1) to be scanned in successive scanning steps (Ti) and each provided as a signal series (Si), - a control unit (3) comprising a safety program (AW) designed to send a shutdown signal (AS) to avoid a hazardous condition, to improve - an object recognition system (4) is arranged in front of the light curtain (1) against a transport direction (TR) and is designed to recognize the objects (O1,O2,O3) and to derive parameters (P) for their geometric shape from them.