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    Please use this identifier to cite or link to this item: http://ir.lib.ncu.edu.tw/handle/987654321/81701

    Title: 遠端螢光粉LED光學效能提升之研究;Study on improving the optical performance of remote phosphor LED
    Authors: 周永芳;Chou, Yung-Fang
    Contributors: 機械工程學系
    Keywords: 遠端螢光粉;光學效能;remote phosphor LED
    Date: 2019-08-16
    Issue Date: 2019-09-03 16:38:27 (UTC+8)
    Publisher: 國立中央大學
    Abstract: 近年來基於螢光粉轉換的白光LED由於具有長壽命、高可靠性、環境保護、安全性和多種應用領域等許多優點而在LED市場中佔有相當大的比例。但為了滿足可持續發展的要求,持續提高LED的發光效率至關重要。將螢光粉層與LED晶片分離以抑制光線再吸收的遠端螢光粉封裝結構是提高發光效率的有效方法,本文利用次波長結構的抗反射特性設計並製作具有半橢圓球型結構的PET薄膜貼附於遠端螢光粉LED表面以再次提高元件的光取出效率,實驗結果證實在遠端螢光粉LED表面貼附結構周期為350nm且結構高度為300nm橢圓球型結構的PET薄膜,遠端螢光粉LED之光取出效率可提升11.76%。此外,遠端螢光粉LED在貼附
    ;Recently, white LEDs based on phosphor conversion have accounted for a considerable proportion of the LED market. To meet the requirements of sustainable development, continual enhancement of LED luminous efficiency is crucial. A remote phosphor package is an efficient method for enhancing luminous efficiency. In this study, the light extraction efficiency of a remote phosphor white LED was enhanced using a hemiellipsoidal antireflection subwavelength structure PET film, which was fabricated to reduce the Fresnel reflection of the LED package surface. The completed antireflection subwavelength structure PET film was integrated on the remote phosphor LED surface through a UV-curing adhesive process. The measured results show that the luminous efficiency was enhanced by approximately 11.76% when the ASS film was used. Moreover, the optical properties of color coordinates, color temperature, and color rendering of remote phosphor LEDs were within the measurement error of the measuring equipment when the ASS film was present.
    However, in typical remote phosphor white LEDs, the phosphor-scattered blue light and phosphor-emitted yellow light have different radiant intensity distributions. Therefore, the angular color distribution becomes non-uniform, and a yellow ring phenomenon appears in the illuminating plane.The utility of low-cost and controllable TiO2 diffuser-loaded encapsulation provided an effective method for improving the angular color uniformity of remote phosphor white LEDs. An inert TiO2 diffuser content of 0.2 wt.% and a phosphor content of 16.0 wt.% in the phosphor layer were determined to be the optimum conditions for obtaining low angular CCT variance, high luminous efficiency, and maintaining the CCT of white LEDs, simultaneously. We found that the angular color uniformity could be improved by 31.82% in the TiO2 diffuser-loaded encapsulation remote phosphor LED, compared with the non-diffuser remote phosphor LED. At a driving current of 350 mA, the luminous flux of the TiO2 diffuser-loaded encapsulation remote phosphor LED was increased by 8.65% relative to the non-diffuser remote phosphor LED. Finally, we showed that incorporating the TiO2 diffuser into the phosphor layer of the remote phosphor white LED did not influence the reliability of the LED.
    Appears in Collections:[機械工程研究所] 博碩士論文

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