LED End of Life Optical Comparator for Aircraft Lighting
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Solution Overview
Problem
Aircraft lighting manufacturers face challenges in determining the end of life of LED light fixtures due to unpredictable degradation, leading to potential non-compliance with FAA specifications, as existing methods are either inaccurate or complicate certification.
Innovation Solution
A method comparing the light output of a control LED, which is energized briefly, with that of an illumination LED, using a sensor to determine degradation, and activating alarms or disabling the fixture if the illumination LED's output falls below a threshold, thereby simplifying certification and improving accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a fixed end of life based on predetermined operating hours is used, then the determination method is simple, but the accuracy of determining when the light output falls below specification is poor
Solution Approach 1:
A control LED is installed in the light fixture that operates for a short period of time to establish a baseline light output measurement. This preliminary action creates a reference point against which the illumination LED's degradation can be measured, enabling accurate end-of-life determination without complex external equipment.
Solution Approach 2:
A sensor is introduced as an intermediary component to measure and compare the light output between the control LED and illumination LED. This mediator translates optical signals into measurable data, allowing the system to objectively determine when the illumination LED has degraded below acceptable thresholds.
2Measurement precision
If software approaches are used to determine end of life, then the determination can account for degradation patterns, but the certification complexity increases
Solution Approach 1:
The patent replaces software-based degradation analysis with a hardware-based optical comparison system. By using physical sensors and control LEDs to directly measure light output ratios, the system achieves degradation detection through hardware mechanisms rather than software algorithms, thereby simplifying certification requirements while maintaining detection accuracy.
3Measurement precision
If the control LED is energized for a long period to establish baseline, then the baseline measurement is accurate, but the control LED degrades and affects measurement accuracy
Solution Approach 1:
The control LED is energized for only a short, limited period of time—just enough to establish a baseline measurement—rather than continuously or for extended periods. This partial action provides sufficient baseline data while minimizing the control LED's exposure to degradation, ensuring it remains a reliable reference over the long term.
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 approach allows for precise determination of LED light fixture end of life, enhancing compliance with FAA requirements and simplifying certification processes by using a comparator method that accounts for variations in LED output and ambient conditions without requiring software.
Implementation Method 1
A sensor measures a light output of the control LED and a light output of the illumination LED
Data Source
AI summary
The present invention provides methods and devices for determining end of life of a light fixture by comparing the light output of a control LED of the fixture with the light output of an illumination LED of the fixture. The control LED is energized for a short period of time for the purpose of measuring its light output. The illumination LED is energized for the duration of time of the light fixture itself. In this way, the amount of degradation of the illumination LED can be determined by comparison with the control LED. If the light output of the illumination LED falls below a threshold level, actions may be take, such as, for example, sounding an alarm.