由於白光發光二極體逐漸普遍，而藍光發光二極體搭配釔鋁石榴石螢光體(Yttrium Aluminum Garnet, YAG)，則是製作白光發光二極體最簡易的方式，因此深入探討其發光機制，即為此領域的研究重點。 本論文主要在建立螢光粉發光光譜模型，描述藍光發光二極體與螢光體之間的微觀物理機制，其中再吸收與再輻射也將一併考慮，並配合演算法進行模擬計算，得到適當之參數，吸收係數與轉換效率。 再以此物理模型模擬藍光發光二極體入射螢光體後，在螢光體內部每一層的激發、吸收與轉換現象。由模型得到的光譜可以預測不同厚度的螢光粉發光光譜，在激發波段，其模擬光譜與實驗光譜貼近；而輻射波段，光譜分布雖然無法完全符合，但其趨勢一致。 To investigate the luminescence mechanism of white LED which is produced by using blue LED exciting yttrium aluminum garnet (YAG) phosphor is the point in this field all the time, because of its popular applications and the simplest way to fabricate. In this thesis, according to not only the physical mechanism which includes excitation, emission, absorption, and conversion between the blue LED and phosphor, but also the re-absorption and re-emission of phosphor, the emission spectrum model is established. Besides, the absorption coefficient and conversion coefficient of phosphor are carried out by algorithm. Therefore, the phenomena of excitation, emission, absorption, and conversion inside each layer of phosphor would be described by this spectrum model. In addition, the luminescence spectrum of phosphor with different thickness could be predicted by this spectrum model. The simulated spectrum is close to experiment spectrum over the excitation wavelength range, and the tendency is the same, even though the magnitudes are different over the emission wavelength range.
