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

Jeong Park, Moowhan Shin, Chin C. Lee

Research output: Contribution to journalArticle

89 Citations (Scopus)

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 languageEnglish
Pages (from-to)2656-2658
Number of pages3
JournalOptics Letters
Volume29
Issue number22
DOIs
Publication statusPublished - 2004 Nov 15

Fingerprint

infrared lasers
temperature profiles
light emitting diodes
liquid crystals
optical paths
high power lasers
insertion
sapphire
illumination
chips
quantum wells
laser beams
color
filters
temperature

All Science Journal Classification (ASJC) codes

  • Atomic and Molecular Physics, and Optics

Cite this

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Measurement of temperature profiles on visible light-emitting diodes by use of a nematic liquid crystal and an infrared laser. / Park, Jeong; Shin, Moowhan; Lee, Chin C.

In: Optics Letters, Vol. 29, No. 22, 15.11.2004, p. 2656-2658.

Research output: Contribution to journalArticle

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