Abstract
We present a new technique for measuring the temperature profiles of visible LED chips by use of a nematic liquid crystal with IR laser illumination. The LEDs studied have a multi-quantum-well InGaN/GaN/sapphire structure. New features in this technique are the use of a high-power IR laser beam as the sensing light and the insertion of a color filter in the optical path to block the high-intensity LED light. For the LEDs measured, the conversion efficiency decreases by 70% when the junction temperature rises from 25 to 107°C. This technique is a valuable tool for studying the performance of LEDs as a function of junction temperature.
| Original language | English |
|---|---|
| Pages (from-to) | 2656-2658 |
| Number of pages | 3 |
| Journal | Optics Letters |
| Volume | 29 |
| Issue number | 22 |
| DOIs | |
| Publication status | Published - 2004 Nov 15 |
All Science Journal Classification (ASJC) codes
- Atomic and Molecular Physics, and Optics