Optoelectronic Sensor Dual Threshold Reflection Detection
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Solution Overview
Problem
Existing optoelectronic safety light grids struggle with detecting reflected light beams, leading to potential misalignment and reduced availability due to angular limitations of light transmission and reception, and are hindered by the presence of reflective surfaces in the protective field, which complicates their use in applications with steel tools or sheets.
Innovation Solution
An optoelectronic sensor design featuring strips with transmitting and receiving elements forming transmit/receive pairs, with an evaluation unit that distinguishes between direct and reflected light by using two switching thresholds, allowing detection of reflections even when the direct light path is clear, and encoding light beams to prevent interference from adjacent sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the light transmission angle is limited to +/-5° to +/-10° to prevent mirroring, then the reliability of object detection is improved, but the ease of alignment between transmitters and receivers deteriorates and the device becomes more sensitive to vibrations
Solution Approach 1:
The patent divides the light reception function into two distinct pathways: a direct light path receiver and a reflected light path receiver. By segmenting the reception system, the patent can accept light from different angles - direct light for normal operation and reflected light for vibration compensation - thereby resolving the contradiction between reliable detection and alignment sensitivity.
Solution Approach 2:
The patent introduces a reflected light receiver as an intermediary element that captures light reflected from surfaces. This intermediary pathway allows the system to detect light energy even when direct alignment is disrupted by vibrations, effectively mediating between the transmitter and the main receiver to maintain detection reliability without requiring precise angular alignment.
2Reliability
If the light transmission angle is limited to +/-5° to +/-10° to prevent mirroring, then the reliability of object detection is improved, but the productivity of the system deteriorates due to restricted availability during vibrations
Solution Approach 1:
The patent implements a dynamic detection system that automatically switches between direct light path detection and reflected light path detection based on environmental conditions. When vibrations occur, the system dynamically transitions to using reflected light signals, maintaining productivity and availability without compromising detection reliability.
Solution Approach 2:
The patent changes the operational parameters of the light detection system by introducing a second reception pathway with different angular characteristics. The reflected light receiver is positioned to capture light at angles different from the direct light path, allowing the system to adjust its detection parameters dynamically and maintain productivity under varying vibration conditions.
3Reliability
If reflective surfaces are forbidden in the protective field to prevent mirroring, then the reliability of detection is improved, but the adaptability of the sensor deteriorates for applications with steel tools or sheets
Solution Approach 1:
The patent converts the harmful effect of reflected light (which causes mirroring errors) into a beneficial detection pathway. By intentionally designing a reflected light receiver that utilizes reflected light from steel tools and sheets, the patent eliminates mirroring errors while maintaining adaptability for industrial applications involving reflective surfaces.
Solution Approach 2:
The patent creates a universal detection system that functions in both direct light path mode and reflected light path mode. The dual-receiver configuration allows the same sensor system to adapt to different application scenarios - whether reflective surfaces are present or absent - thereby achieving versatility across various industrial applications without compromising detection reliability.
4Measurement precision
If two switching thresholds are used to detect reflections, then the measurement precision of light detection is improved, but the device complexity increases
Solution Approach 1:
The patent applies parameter changes by introducing a second switching threshold for reflected light detection in addition to the first threshold for direct light. This dual-threshold approach enhances measurement precision by distinguishing between direct and reflected light paths, while the evaluation unit manages the complexity through systematic threshold comparison logic.
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 detection of reflections, reduces misalignment issues, and increases sensor availability by preventing overdriving of receiving elements, enabling better separation of codes and improved sensitivity, thus ensuring safer operation by preventing dangerous movements due to adverse reflections.
Implementation Method 1
a first strip (8) with transmitting elements (L1, Ln) and/or receiving elements (E1, En) and a second strip (10) with transmitting elements and receiving elements
Implementation Method 2
an evaluation unit (22) for evaluating the light received from the receiving elements (E1, En)
Implementation Method 3
it is possible for light beams from the transmitter to reach the receiver through reflecting or reflecting surfaces in the vicinity of the protective field
Data Source
Figure 1~3
Figure 4~5
AI summary
The sensor (1) has two strips (8, 10) comprising transmitter elements (L1-Ln) and receiver elements (E1-En). The transmitter elements of one of the strips form transmitter/receiver pairs with receiver elements of the other strip for the formation of a protective field (14). A light beam (12) is between the transmitter elements and receiver elements counts when received light falls below a lower switching threshold (S1). An upper switching threshold (S2) is provided in an evaluation unit (22) whose value lies above the value of the lower switching threshold.