Pulsed Phosphor Lighting Sensor Fault Detection
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Solution Overview
Problem
Existing lighting devices with laser diodes and phosphor elements for emitting pump radiation and conversion light lack effective monitoring and fault detection mechanisms, particularly in scenarios where the phosphor element may malfunction, leading to potential eye hazards due to focused pump radiation.
Innovation Solution
Incorporating a sensor to monitor the conversion light intensity and pulsed operation of the phosphor element, which decreases conversion light intensity by at least 10% between pulses, allowing for better metrological detectability and reducing the risk of eye hazards by switching off the laser diode in fault situations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If continuous operation of the phosphor element is maintained, then luminous efficiency is improved, but metrological detectability and safety monitoring deteriorate
Solution Approach 1:
The phosphor element is operated in pulsed mode instead of continuous operation, creating periodic excitation cycles. This allows the conversion light intensity to decrease between pulses, enabling the sensor to detect faults by monitoring whether the expected intensity reduction occurs. The periodic action resolves the contradiction by providing measurement opportunities without significantly compromising overall luminous efficiency.
2Reliability
If a sensor is added to monitor conversion light intensity, then safety and detectability are improved, but device complexity increases
Solution Approach 1:
The sensor monitors the conversion light intensity generated by the phosphor element itself, using the system's own operational output for self-diagnosis. This self-service approach enables fault detection without requiring external complex monitoring equipment, as the system uses its own light emission characteristics to detect abnormalities.
3Measurement precision
If pulsed operation is implemented to improve detection, then metrological detectability is improved, but luminous efficiency decreases
Solution Approach 1:
The pulsed operation uses partial action by maintaining continuous pumping of the phosphor element but only detecting during specific intervals when the element is not actively emitting. This allows the sensor to measure the decay of conversion light intensity without interrupting the overall luminous output, thereby improving detection precision while minimizing impact on luminous efficiency.
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 solution enhances metrological detectability and safety by modulating the signal and reducing the probability of external light interference, while maintaining luminous efficiency through alternating operating states that balance reliability and efficiency.
Implementation Method 1
a phosphor element, which during operation is irradiated by the laser diode and thereby excited and serves for converting the pump radiation into conversion light
Implementation Method 2
the sensor is provided for monitoring the pump radiation conversion and at the same time is designed to detect a conversion light intensity
Data Source
AI summary
A lighting device provides a lighting unit for emitting useful light and a sensor. The unit includes a laser diode for emitting pump radiation and a phosphor element, which during operation is irradiated by the laser diode and thereby excited and serves for converting the pump radiation into conversion light, which conversion light at least proportionally forms the useful light. The sensor monitors the pump radiation conversion and at the same time detects a conversion light intensity, and is arranged with respect to the phosphor element of the unit so that a portion of the useful light and a measurement portion of the conversion light is incident on the sensor. The lighting device operates so that the phosphor element at least at times is irradiated in a pulsed manner and thereby excited so that between two pulses the conversion light intensity detected by the sensor decreases by at least 10%.