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Optics Letters

Optics Letters


  • Vol. 29, Iss. 22 — Nov. 15, 2004
  • pp: 2656–2658

Measurement of temperature profiles on visible light-emitting diodes by use of a nematic liquid crystal and an infrared laser

Jeong Park, Moowhan Shin, and Chin C. Lee  »View Author Affiliations

Optics Letters, Vol. 29, Issue 22, pp. 2656-2658 (2004)

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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.

© 2004 Optical Society of America

OCIS Codes
(110.6820) Imaging systems : Thermal imaging
(120.6780) Instrumentation, measurement, and metrology : Temperature
(120.6810) Instrumentation, measurement, and metrology : Thermal effects
(160.3710) Materials : Liquid crystals
(230.3670) Optical devices : Light-emitting diodes
(230.5590) Optical devices : Quantum-well, -wire and -dot devices

Jeong Park, Moowhan Shin, and Chin C. Lee, "Measurement of temperature profiles on visible light-emitting diodes by use of a nematic liquid crystal and an infrared laser," Opt. Lett. 29, 2656-2658 (2004)

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