Determination of coefficient of thermal expansion in high power GaN-based light-emitting diodes via optical coherent tomography

Ya Ju Lee, Yung Chi Yao, Yi Kai Haung, Meng Tsan Tsai

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

    Abstract

    One of the most challenging issues when operating a high-power light-emitting diode (LED) is to conduct appropriate packaging materials for the reliable thermal management of the entire device. Generally, the considerable amount of heat produced around the junction area of the LED would transfers to the entire device, and causes thermal expansion in the packaging material. It induces strain inevitably, and hinders the output performances and possible applications of high-power LEDs. The coefficient of thermal expansion (CTE) is a physical quantity that indicates the expansion to which value a material will be upon heating. Therefore, as far as an advancement of thermal management is concerned, the quantitative and real-time determination of CTE of packaging materials becomes more important than ever since the demanding of high-power LEDs is increased in recent years. In this study, we measure the CTE of GaN-based (λ = 450 nm) high-power LED encapsulated with polystyrene resin by using optical coherent tomography (OCT). The displacement change between individual junctions of OCT image is directly observed and recorded to derive the CTE values of composed components of the LED device. The obtained instant CTE of polystyrene resin is estimated to be around 10 × 10−5/°C, which is a spatial average value over the OCT scanning area of 10 μm × 10 μm. The OCT provides an alternative way to determine a real-time, non-destructive, and spatially resolved CTE values of the LED device, and that shows essential advantage over the typical CTE measurement techniques.

    Original languageEnglish
    Title of host publicationAdvances in Intelligent Information Hiding and Multimedia Signal Processing - Proceedings of the 13th International Conference on Intelligent Information Hiding and Multimedia Signal Processing,
    EditorsJeng-Shyang Pan, Pei-Wei Tsai, Lakhmi C. Jain, Junzo Watada
    PublisherSpringer Science and Business Media Deutschland GmbH
    Pages147-152
    Number of pages6
    ISBN (Print)9783319638553
    DOIs
    Publication statusPublished - 2018 Jan 1
    Event13th International Conference on Intelligent Information Hiding and Multimedia Signal Processing, IIH-MSP 2017 - Matsue, Shimane, Japan
    Duration: 2017 Aug 122017 Aug 15

    Publication series

    NameSmart Innovation, Systems and Technologies
    Volume81
    ISSN (Print)2190-3018
    ISSN (Electronic)2190-3026

    Other

    Other13th International Conference on Intelligent Information Hiding and Multimedia Signal Processing, IIH-MSP 2017
    CountryJapan
    CityMatsue, Shimane
    Period17/8/1217/8/15

    Keywords

    • Light-emitting diodes
    • Optical coherence tomography
    • Packaging materials

    ASJC Scopus subject areas

    • Decision Sciences(all)
    • Computer Science(all)

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