摘要
相較於傳統紫外汞燈，深紫外發光二極體(Deep ultraviolet light emitting diode，DUVLED，亦稱作UVCLED)不僅輻照强度高、響應速度快、壽命長、殺菌效率高等諸多優點，且無異味、無二次污染，更是對人體和環境具有明顯優勢。然而目前UVCLED外量子效率(External quantum efficiency，EQE)仍然偏低，商業化UVCLED產品EQE普遍在5%左右，其餘大量轉換成熱。
本文利用光學基本理論提出一種改良方式，對市場現有產品進行改良。於模擬軟體中建構模型，模擬並驗證該優化設計對出光和散熱性能的提升效果，並改善現有產品封裝結構，以達出光提升和壽命延長。
本研究主要分爲光學設計優化和熱學模擬及驗證兩個部分：光學設計部分為現有產品光學效率分析、LightTools光學模型架構、並設計光學優化方案，其中包括：1.對基板厚度優化；2.晶片塑形之優化蝕刻溝槽，並探討溝槽深度及層數對光取出效率之影響；3.晶片底面鋁反射對出光影響；4.添加折射率介於空氣與基板間之中間折射率材料；5.最後將反光杯匯入LightTools進行光學優化模擬，並對光學性能提升進行分析；其次是熱學模擬部分，主要分爲現有產品COMSOL熱傳模型架構、模擬驗證光學方案對散熱性能之影響、實驗量測數據進行收集分析，並以實際值修正模擬值，驗證模擬之正確性。晶片之光取出效率最高可由18.5%提升至38.0%，最高溫度由50.7℃降低至42.7℃。

關鍵字：UVCLED光熱優化模擬、光取出效率、熱分布、能量轉化比例

Abstract
Compared with traditional ultraviolet lamps, deep ultraviolet light-emitting diodes (UVCLED) have high intensity of light distribution, fast responsiveness speed, longer lifetime, high sterilization efficiency. Besides, there is no secondary pollution has been found for the environment which can play an important part in human life. However, external quantum efficiency (external quantum efficiency, EQE) of the current UVCLED is still at a lower level. The EQE of the product of commercial UVCLED is generally around 5%, and the rest of the energy is converted into heat which is a great loss for the energy.
This thesis uses the basic theory of optics to propose a method to improve the existing product in the market. A model had been constructed in the simulation software to simulate and verify the improvement effort of the optimized design for the output of the light and the performance of the heat dissipation. The constructed model for the simulation can improve the output of the light and extend the lifetime of the product by changing the structure of the product in the market.
This study is divided into two main parts: Optimization of optical design and thermal simulation and verification. The part of optical design combine as following parts: 1. The improvement of the thickness of the substrate. 2. The optimization about etching grooves for wafer shaping, and discussing the influence of the efficiency of light extraction. 3. The influence of aluminum reflection on the bottom surface of the chip for light extraction. 4. Add a material which refractive index is between air and the the substrate. 5. Import a reflective cup which can improve the efficiency of the output of the light. The thermal simulation and verification part, which is mainly about the heat transfer model in COMSOL for the products which existed in the market, uses the heat transfer model framework in COMSOL to simulate and verify the influence of the optical design for the thermal dissipation performance. To verify the correctness of the thermal simulation, we measure the percentage of the output of the light from the commercial UVCLED. The efficiency of light extraction of the chip can be raise from 18.5% to 38%, and the highest temperature will be lowered from 50.7℃ to 42.7℃.

Keywords: UVCLED photothermal optimization simulation, light extraction efficiency, heat distribution, energy conversion ratio

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