Directly Determining the Coefficient of Thermal Expansion of High-power Light-emitting Diodes by Optical Coherence Tomography

Ting Wei Yeh, Chun Yang Chou, Chun Ying Huang, Yung Chi Yao, Yi Kai Haung, Meng Tsan Tsai, Ya Ju Lee

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

The coefficient of thermal expansion (CTE) is a physical quantity that indicates the thermal expansion value of a material upon heating. For advanced thermal management, the accurate and immediate determination of the CTE of packaging materials is gaining importance because the demand for high-power lighting-emitting diodes (LEDs) is currently increasing. In this study, we used optical coherence tomography (OCT) to measure the CTE of an InGaN-based (λ = 450 nm) high-power LED encapsulated in polystyrene resin. The distances between individual interfaces of the OCT images were observed and recorded to derive the instantaneous CTE of the packaged LED under different injected currents. The LED junction temperature at different injected currents was established with the forward voltage method. Most importantly, this work validates the hypothesis that OCT can provide an alternative way to directly and nondestructively determine the spatially resolved CTE of the packaged LED device, which offers significant advantages over traditional CTE measurement techniques.

Original languageEnglish
Title of host publication2018 Conference on Lasers and Electro-Optics, CLEO 2018 - Proceedings
PublisherInstitute of Electrical and Electronics Engineers Inc.
ISBN (Print)9781943580422
Publication statusPublished - 2018 Aug 6
Event2018 Conference on Lasers and Electro-Optics, CLEO 2018 - San Jose, United States
Duration: 2018 May 132018 May 18

Publication series

Name2018 Conference on Lasers and Electro-Optics, CLEO 2018 - Proceedings

Conference

Conference2018 Conference on Lasers and Electro-Optics, CLEO 2018
CountryUnited States
CitySan Jose
Period18/5/1318/5/18

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ASJC Scopus subject areas

  • Instrumentation
  • Atomic and Molecular Physics, and Optics

Cite this

Yeh, T. W., Chou, C. Y., Huang, C. Y., Yao, Y. C., Haung, Y. K., Tsai, M. T., & Lee, Y. J. (2018). Directly Determining the Coefficient of Thermal Expansion of High-power Light-emitting Diodes by Optical Coherence Tomography. In 2018 Conference on Lasers and Electro-Optics, CLEO 2018 - Proceedings [8427020] (2018 Conference on Lasers and Electro-Optics, CLEO 2018 - Proceedings). Institute of Electrical and Electronics Engineers Inc..