On-Board Diagnostics for LED Illumination Modules
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Solution Overview
Problem
Conventional LED-based illumination devices face challenges in diagnosing and addressing issues such as heat sinking failures, power requirements, and phosphor degradation, leading to performance degradation and reduced lifetime, as these problems are difficult to access and diagnose once installed.
Innovation Solution
The implementation of an on-board diagnostic system for LED-based illumination modules that estimates elapsed lifetime, detects thermal failures, and adjusts current based on measured flux and temperature, allowing for real-time monitoring and potential alerts for maintenance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Difficulty of detecting and measuring
If conventional LED-based illumination devices are installed, then illumination function is provided, but problems such as heat sinking failures, power requirements, and phosphor degradation are difficult to access and diagnose
Solution Approach 1:
The illumination device performs self-diagnosis by incorporating sensors and processing circuits that automatically monitor operational parameters (heat sink temperature, power consumption, phosphor degradation) and generate diagnostic information without external intervention. The device serves itself by detecting its own degradation states and providing maintenance alerts.
Solution Approach 2:
The system continuously monitors operational parameters and feeds this information back to the control circuit, which compares actual values against threshold values and generates appropriate diagnostic outputs. This closed-loop feedback mechanism enables real-time detection of heat sinking issues, power requirements, and phosphor degradation.
2Duration of action of moving object
If LED-based illumination devices operate continuously, then illumination is maintained, but performance degradation and reduced lifetime occur
Solution Approach 1:
The diagnostic system detects degradation trends early in the LED's operational life by continuously monitoring parameters such as heat sink temperature, power consumption, and phosphor performance. By identifying potential failures before they occur, the system enables preventive maintenance to extend the operational lifetime and maintain reliability.
3Difficulty of detecting and measuring
If diagnostic functions are added to LED-based illumination devices, then real-time monitoring capability is improved, but device complexity increases
Solution Approach 1:
The processing circuit serves multiple functions: it controls the LED illumination, monitors operational parameters (temperature, power consumption, phosphor degradation), compares values against thresholds, and generates diagnostic outputs. This multi-functionality reduces the need for separate dedicated diagnostic components, thereby limiting the increase in device complexity.
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
Enables proactive maintenance by providing real-time monitoring and alerts, extending the operational lifetime of LED-based illumination modules by identifying and addressing issues before they lead to significant performance degradation.
Implementation Method 1
The present invention relates to illumination modules that include Light Emitting Diodes (LEDs)
Implementation Method 2
degradation of a phosphor coating
Data Source
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Figure 3A
AI summary
A light emitting diode (LED) based illumination module performs on-board diagnostics. For example, diagnostics may include estimating elapsed lifetime, degradation of phosphor, thermal failure, failure of LEDs, or LED current adjustment based on measured flux or temperature. The elapsed lifetime may be estimated by scaling accumulated elapsed time of operation by an acceleration factor derived from actual operating conditions, such as temperature, current and relative humidity. The degradation of phosphor may be estimated based on a measured response of the phosphor to pulsed light from the LEDs. A thermal failure may be diagnosed using a transient response of the module from a start up condition. The failure of LEDs may be diagnosed based on measured forward voltage. The current for LEDs may adjusted using measured flux values and current values and a desired ratio of flux values. Additionally, the LED current may be scaled based on a measured temperature.