採用螢光粉封裝之白光LED,除了會隨著不同的封裝形式,有著不同的光學特性外,不同種類的螢光粉,亦有不同的轉換效率,對白光LED的發光效率有直接影響,所以,對於螢光粉模型與其轉換效率之研究是一個相當重要的課題。本論文中,為了得到較精確的螢光粉轉換效率,我們改良了傳統實驗架構,因此,提高轉換效率分析上的準確性。另外,為了探討矽酸鹽(Silicate)螢光粉於白光LED封裝之光學特性,我們建立矽酸鹽螢光粉的光學模型,再將模型中得到之轉換效率與實驗量測結果做比較。As well known, in addition to the ways of packaging, the conversion efficiency of the various applied phosphors also has greatly effect on the luminous efficiency in the phosphor-based white light LEDs. In such a way, it has become a very important issue that how to evaluate the quantum efficiency of phosphors. In this thesis, we has proposed an improved measuring setup for obtain the precise quantum efficiency of phosphors. The accuracy of the measurement has much enhanced in analysis. Besides, we also study the optical model to precisely describe the spatial and the chromatic distribution of the lights emitted from blue LEDs covered with silicate phosphors.