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Identifying and evaluating aging signatures in light emitting diode lighting systems

Abstract : In this work, the degradation of light emitting diodes (LEDs) is studied by identifying and evaluating their aging signature during the stress time. The custom-made experimental test bench is built for realization of the test measurement. Through this experimental test bench, it allows to test a large amount of LED samples and enable to select different temperature condition and different current stress level. There are four different types of LED with similar characteristic in term of their color temperature, IF, VF, power (1W) and as monochip, but different technology coming from Cree, Osram, Philips and Seoul Semiconductor. The devices are firstly characterized their electrical and photometrical characteristic at their initial state, then they are submitted to different current stress condition at low current stress (350mA) and high current stress (1000mA) while the thermal stress is fixed at one temperature (50°C). The study of these devices failure mechanism is archived by using the primary method based on the electrical and photometrical characterization of the devices that allows to evaluate their degradation at different locations of the device components such as semiconductor chip, interconnection and device's package. The electrical characteristic of the device's I-V curve: at low injected current level and reverse bias allow us to identify the degradation characteristic of device's semiconductor chip, at high injected current level allows us to determine the degradation of device's ohmic contact and photometric characteristic allows us to evaluate the degradation of device's package system.
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Submitted on : Friday, May 25, 2018 - 9:32:05 AM
Last modification on : Saturday, August 15, 2020 - 4:07:56 AM
Long-term archiving on: : Sunday, August 26, 2018 - 1:21:32 PM


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  • HAL Id : tel-01799687, version 1



Sovannarith Leng. Identifying and evaluating aging signatures in light emitting diode lighting systems. Electric power. Université Paul Sabatier - Toulouse III, 2017. English. ⟨NNT : 2017TOU30035⟩. ⟨tel-01799687⟩



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