Light Source Degradation Prediction Using Piecewise Functions
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Solution Overview
Problem
Current methods for controlling the operation of light sources, particularly light-emitting diodes, lack precision in predicting degradation without explicit luminous flux measurement, leading to unreliable prediction of failure points and operating parameter tracking.
Innovation Solution
A method that calculates degradation using piecewise defined functions based on different sets of function variables and constants over specific time periods, allowing for accurate prediction and maintenance by updating function constants over the light source's operational life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If explicit luminous flux measurement is performed to determine degradation, then measurement precision is improved, but device complexity and cost increase significantly
Solution Approach 1:
The patent introduces an intermediary approach by using electrical parameters (current, voltage, resistance) as mediators to indirectly determine degradation. Instead of directly measuring luminous flux, the system measures electrical characteristics that correlate with degradation, thus avoiding complex optical measurement devices while still achieving accurate degradation assessment
Solution Approach 2:
The patent replaces complex optical measurement systems with simpler electrical measurement systems. By substituting luminous flux measurement (which requires sophisticated optical equipment) with electrical parameter measurement (which can be done with standard electrical sensors), the system achieves degradation determination with significantly reduced device complexity
2Reliability
If a single degradation function is used throughout the light source lifetime, then device complexity is reduced, but prediction accuracy deteriorates due to varying degradation rates over time
Solution Approach 1:
The patent divides the light source lifetime into multiple time periods, with each period having its own degradation function. This segmentation allows the system to capture the varying degradation rates at different stages of the light source life (e.g., initial burn-in period, stable operation period, end-of-life period) while keeping each individual function relatively simple
Solution Approach 2:
The patent implements a dynamic degradation assessment system that adapts the calculation model based on the current operational stage of the light source. By switching between different degradation functions according to the elapsed time or operational conditions, the system maintains high prediction reliability throughout the entire lifetime without requiring an overly complex single unified model
3Measurement precision
If multiple degradation functions with different constants are used over time periods, then prediction accuracy is improved, but calculation complexity increases
Solution Approach 1:
The patent performs preliminary determination of the appropriate degradation function based on pre-defined time periods or operational stages. By establishing the applicable function in advance based on elapsed time or operational milestones, the system avoids complex real-time decision-making and simplifies the calculation process while maintaining high precision through appropriate function selection
Data Source
Figure 1
Figure 2a~2b
AI summary
The invention relates to a method for operating a light source, wherein a plurality of light source operating variables such as light source current and/or light source temperature are stored and, on the basis of a function dependent on several function variables and a set of function constants for calculating the degradation rate, the degradation of the light source is calculated and the operation of the light source is controlled depending on the calculated degradation and/or a maintenance function is executed depending on the determined degradation.The method is characterized by the fact that, over the entire operating time of the light source until a first operating time (T1) is reached, a first function, dependent on several function variables and a first set of function constants, is used to calculate the degradation rate, and after reaching the first operating time (T1), a second function, dependent on several function variables and a second set of function constants, is used to calculate the degradation rate.