Reliability Estimation and Failure Analysis of LEDs with Various Currents and Correlated Color Temperatures for
J Lokesh1, S G Kini1, A N Padmasali1
1Department of Electrical and Electronics Engineering, Manipal Academy of Higher Education, Manipal Institute of Technology, Manipal, Karnataka 576104, India.
ACS Omega
|March 10, 2025
Summary
Warm white LEDs degrade faster than cool white LEDs, with chip degradation being the main cause of reduced light output. Lumen performance was similar across different specifications for the same LED power rating.
Area of Science:
- Solid-state lighting
- Optoelectronics
- Materials science
Background:
- LEDs offer diverse correlated color temperatures (CCTs) and power specifications.
- Lack of reliability data complicates LED selection for consumers and manufacturers.
- Physics of failure analysis is essential for understanding LED lifespan.
Purpose of the Study:
- To evaluate the reliability and lifetime performance of 3.84 W phosphor-converted LEDs.
- To compare warm white (WW) and cool white (CW) LEDs under accelerated testing.
- To analyze failure mechanisms using various electrical and optical measurements.
Main Methods:
- Accelerated testing in an environmental chamber.
- Spectra Power Distribution (SPD), photoluminescence, capacitance-voltage (C-V), and current-voltage (I-V) measurements.
- Physics of failure analysis.
Main Results:
- WW LEDs exhibit faster lumen performance decay than CW LEDs.
- Chip degradation is the primary failure mechanism for reduced light output in both WW and CW LEDs.
- Lumen performance is comparable across different voltage/current specifications for the same power rating, but Duv differs in CW LEDs.
Conclusions:
- LED reliability data is critical for informed luminaire design and manufacturing.
- Understanding failure modes aids in improving LED longevity and performance.
- WW LEDs may require specific design considerations due to faster lumen depreciation.
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