本研究中,我們利用具有表面微結構之薄膜型氮化鎵LED搭配外腔式光源機構,設計出高指向性之光源機構模型。首先,針對氮化鎵LED的幾何結構以及光學特性進行量測,並經由此實驗數據建立出相似度高達99.8%的LED光學模型。接著利用此模型設計一外腔式光源機構,使LED的光線發散角得以從±90°縮小至±30°以內,並計算出光耦合效率、能量提升比例以及散角分佈。最後,我們將此光源機構的實驗數據與模擬結果一一進行比較與探討,進而得到一高精準度之外腔式光源機構模型,而此模型也有利於之後進一步優化的設計。 In this thesis, we incorporate an external cavity with the surface texture for ThinGaN LEDs to obtain a high-directional light source. First of all, we measure the geometric structure on the top surface of ThinGaN LEDs and the characteristic of optical parameters. According to the information, we build up a precise optical model of ThinGaN LED to design an external cavity with special light cone of 30°, which is different from 90° of general LEDs. The output coupling efficiency, enhancement ratio, and spatial distribution are analyzed. Finally, we compare the experiment results with the simulation, and the characteristic of the new light source is discussed.