Light Source Diagnostic Unit for Photobiological Safety
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Solution Overview
Problem
Modern machine vision lighting systems, particularly those using LEDs, face challenges in ensuring photobiological safety due to potential increased light intensity beyond permissible limits, which can endanger people nearby, especially if there are errors or malfunctions in the light source operation.
Innovation Solution
A lighting device with a detection unit that monitors power variables correlated with light intensity and triggers an action to reduce intensity independently of the control unit when these variables exceed predetermined limit values, ensuring safe operation by interrupting or reducing electrical current or voltage supply to the light source, thus preventing excessive light emission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the light source operates at high intensity to meet machine vision lighting requirements, then the illumination quality improves, but photobiological safety risks increase
Solution Approach 1:
The diagnostic unit continuously monitors power variables and compares them against limit values before dangerous intensity levels are reached. By detecting potential failures early and triggering preventive actions (reducing intensity or shutting down), the system prevents photobiological hazards before they occur, rather than reacting after damage has happened.
Solution Approach 2:
The system implements a closed-loop feedback mechanism where the diagnostic unit monitors power variables, compares them to predetermined limit values, and automatically adjusts the light intensity through the control unit. This continuous monitoring and automatic adjustment ensures the light source operates within safe intensity boundaries while maintaining optimal performance.
2Measurement precision
If the control unit is made more complex to regulate intensity precisely, then lighting control accuracy improves, but system reliability decreases
Solution Approach 1:
The system is divided into functionally independent units: the control unit for intensity regulation and the diagnostic unit for safety monitoring. This segmentation allows each unit to be optimized for its specific function while reducing the risk that a failure in one unit will compromise the entire system. The diagnostic unit can independently verify safety parameters without being affected by control unit malfunctions.
Solution Approach 2:
The diagnostic unit continuously monitors power variables and compares them against predetermined limit values before dangerous conditions occur. By detecting potential failures early and triggering preventive actions, the system maintains reliability even when the control unit becomes complex, as the diagnostic unit serves as an independent safety verification layer.
3Object-affected harmful factors
If independent diagnostic monitoring is added to ensure safety, then photobiological safety improves, but device complexity increases
Solution Approach 1:
The diagnostic unit is designed to monitor multiple power variables (electrical current, voltage, or other intensity-correlated parameters) using a single integrated system. This multi-functional approach allows comprehensive safety monitoring without proportionally increasing device complexity, as the same diagnostic infrastructure serves multiple monitoring purposes simultaneously.
Solution Approach 2:
The diagnostic unit automatically monitors power variables, compares them to limit values, and triggers safety actions without requiring external intervention. The system performs self-diagnosis and self-protection, reducing the need for additional complex external safety systems while maintaining high photobiological safety standards.
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
The solution provides reliable protection against undesirably high light intensity, ensuring photobiological safety by automatically reducing light emission to safe levels, even in case of control unit malfunctions, and meets safety standards like SIL 1 as per IEC 61508:2010, thereby preventing risk group escalation.
Implementation Method 1
a light source, preferably a light-emitting diode, of a lamp emits light
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
To provide a light source (1) that offers reliable protection against an undesirably increased emitted light intensity, the light source (1) is equipped, according to the invention, with a light source (10) and a control unit (4), which supplies the light source (7) with an electric current (i) or an electric voltage and is designed to regulate the intensity (Int) of the emitted light via the electric current (i) or the electric voltage, and with a detection unit (20) that detects at least one power parameter (G_ist) of the light source (10). Furthermore, a diagnostic unit (2) is provided that compares the at least one power parameter (G_ist) with at least one predetermined limit value (G) and triggers an action that reduces the intensity (Int) independently of the control unit (4) as soon as the at least one power parameter (G_ist) reaches or exceeds the at least one limit value (G).