在本論文中，探討螢光粉於白光LED封裝之光學品質及修正螢光粉之光學模型，我們結合蒙地卡羅（Monte-Carlo）光追跡法及米氏散射(Mie scatter)原理模擬光線於螢光粉膠體中傳遞時所造成的體散射效應。在模型中我們紀錄藍光被螢光粉所吸收的空間分佈，為螢光粉激發之黃光分佈光源。藉由藍光與黃光兩次光追跡來描述白光LED之光學行為。並使用光譜線性疊加的方式，得到準確之白光光譜，並計算其色座標與色溫值。由實驗與模擬之驗證與分析，我們成功地建立等效YAG螢光粉之光學模型，並應用於白光LED封裝之分析，可對於不同白光LED封裝模擬分析其出光能量與色彩表現。

In this thesis, we study the optical model to describe the YAG powder as he yellow phosphor in white light LEDs with GaN chips. We apply Monte-Carlo ray tracing and volume Mie scattering to simulate the blue light and re-generated yellow light in the phosphor powder. We first record the position-dependent absorption of the blue lights and transfer into the yellow lights. Accordingly, we can describe the generation of white lights by the phosphor-based LED. Through the comparison between the experimental measurement and simulation, we successfully build up the optical model of YAG phosphors. Finally, we apply the model to the design of LED package for obtaining accurate light output and color behavior.

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