RESEARCH PAPER
An approach to analyse of LED degradation heterogeneity in step-stress accelerated testing
1
Faculty of Military Technology, University of Defence, Czech Republic
2
Faculty of Mechanical Engineering, Lublin University of Technology, Poland
3
Brno University of Technology, Czech Republic
4
Le Quy Don Technical University, Viet Nam
These authors had equal contribution to this work
Submission date: 2025-09-20
Final revision date: 2025-12-04
Acceptance date: 2026-01-29
Online publication date: 2026-02-18
Corresponding author
KEYWORDS
Light emitting diodereliabilitydegradation processstep-stress accelerated testdegradation heterogeneity
TOPICS
ABSTRACT
Light-emitting diodes (LEDs) have become indispensable in modern applications owing to their high energy efficiency, long lifespan, and robustness compared to conventional light sources. Given these attributes, the reliability of LEDs has become a crucial factor, directly influencing the ability of systems and devices to perform their intended functions over time. However, variations in materials, structures, and manufacturing processes introduce heterogeneity in their degradation behaviour, even under identical operating conditions. In applications demanding brightness stability, colour rendering, and reliability prediction, degradation homogeneity is crucial, making the analysis of LED heterogeneity essential. This article investigates such heterogeneity using feature extraction methods, kernel density estimation, and divergence measures based on degradation data obtained from optimized step-stress accelerated tests. The proposed approach is used to quantify and evaluate LED degradation variability and has clear implications for reliability assessment and predictive modelling.
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