Abstract
In this case study, we investigate the degradation process of light-emitting diodes (LEDs), which is used as a light source in DNA sequencing machines. Accelerated degradation tests are applied by varying temperature and forward current, and the light outputs are measured by a computerized measuring system. A degradation path model, which connects to the LED function recommended in Mitsuo (1991), is used in describing the degradation process. We consider variations in both measurement errors and degradation paths among individual test units. It is demonstrated that the hierarchical modeling approach is flexible and powerful in modeling a complex degradation process with nonlinear function and random coefficient. After fitting the model by maximum likelihood estimation, the failure time distribution can be obtained by simulation.
Original language | English (US) |
---|---|
Pages (from-to) | 229-237 |
Number of pages | 9 |
Journal | Quality and Reliability Engineering International |
Volume | 27 |
Issue number | 2 |
DOIs | |
State | Published - Mar 2011 |
Keywords
- LED lighting
- accelerated degradation testing
- mixed effect
- nonlinear regression
- reliability prediction
- repeated measurement
ASJC Scopus subject areas
- Safety, Risk, Reliability and Quality
- Management Science and Operations Research