由於近年來LED製程的進步，促使低功率LED廣泛地應用於車輛的指示燈與尾燈，而車用霧燈與頭燈尚未被廣泛地應用，最主要原因在於必須使用高亮度LED方能達成照明之需求。由於高亮度LED的輸入功率高，使得散熱問題相當受到重視，因此在高功率LED的應用上若無有效的熱管理，輕則LED的發光效率及壽命隨著其晶片溫度的升高而快速遞減，重則導致晶片損毀。有鑑於此，本文將從LED投射模組著手研究，並考量兩種不同光型配置進行散熱設計，來維持相似的散熱效能且模組的重量不至於相差太遠，以提供投射模組多樣化的選擇。接著再將研究範圍擴展至車用霧燈，於產品材料、外觀尺寸與光型配置等不變更的限制下，藉由改良原始的散熱模組來解決LED霧燈內部投射模組之散熱問題，使得LED晶片的溫度降幅高達16.6℃。最後透過專利檢索，參考LED車頭燈之相關光型配置技術，以此為基礎來設計符合Toyota Vios之LED車頭燈，於實車測試數據中可確認各LED晶片溫度皆可保持在104℃以內，遠低於其失效溫度150℃；綜合歸納來說，值得一提是本研究所設計的散熱模組中，不但僅採用被動式散熱設計，而且也避免使用熱管，來去除其在震動環境的不確定因素，因此大幅提昇立即量產的可能性。
本研究利用計算流體力學分析軟體，針對各種LED燈具模型進行模擬分析與散熱設計，藉由改良分析後設計出對於產品有較佳效能之散熱模組，並整合實驗驗證與模擬分析之結果，以探討本文所建構之模擬結果與實際量測間之誤差。比較結果顯示，本文之模擬與實驗間之誤差皆在6℃以下，在考量熱阻值與LED功率效正下所模擬之結果，將誤差縮小至1.5℃以內，而LED晶片溫度皆處於安全操作範圍，在此足以證明本文所建構之數值模擬方法具有其相當之可信度。總結來說，本研究所建立之結合數值模擬、CNC實體製作與實驗驗證的研發設計流程，成功地開發出新型的Hybrid投射模組，其LED比改良ARTC投射模組降低2℃，可提供各種LED燈具應用；同時也完成了LED霧燈與Toyota Vios之LED頭燈的散熱設計，能使LED之最高溫度大幅下降，且符合目前LED燈的操作溫度；本研究之完成將能幫助解決LED應用於車用燈具時之散熱問題，並可作為後續LED燈具之散熱研究的參考與應用。

Due to the quick response time and energy-saving characteristics, the low-power LED has been applied extensively to the vehicle signal and tail lights. However, only high-brightness LED can provide sufficient luminous flux to meet with the rigorous standard for automobile lighting regulation. Fog lamp and headlamp are two typical examples which do not commonly choose LED light source due to the severe heat-dissipating problem under a long-time operation. Thus, this integrated numerical, mockup-fabricating, and experimental investigation aims to provide thermal designs for a series of LED vehicle lighting devices, which include the light-projection module, the fog lamp, and the headlamp. At first, comprehensive CFD simulations are executed on the above applications to evaluate several thermal approaches for attaining an optimized thermal design. Then, these corresponding mockups are fabricated via the CNC technology for experimentally verifying their heat-removing capabilities. Furthermore, the thermal performances are measured under an isothermal chamber or the on-board environment for validating the numerical outcomes in a systematical and practical manner. As a result, after taking the contact resistances and LED power calibration into account, all thermal-performance comparisons between numerical and experimental results indicate an acceptable deviation within 1.5°C.
Regards to the thermal management on LED lighting devices, a hybrid light-projection module is designed firstly with a 2°C reduction on LED junction temperature compared to the ARTC module’s performance. Obviously, this superior light-projection module can be utilized in constructing many LED lighting devices in the future. Moreover, under the same constrains on material, exterior dimension, and optical arrangement, a new LED fog lamp is successfully designed and fabricated to decrease its LED junction temperature by a remarkable 16.6°C. At last, a thermal management of LED headlamp on Toyota Vios is proposed and constructed by considering the space limitation and optical arrangement. Also, for the case of a 10 LED modules (34-Watt in total) and a 64°C environmental temperature, the on-board measurement shows that the LED junction temperatures are located below 104 °C, which is well below the operating safety limit (150 °C). In conclusion, the accomplishment of this research offers a rigorous and systematic design scheme for the thermal management of the LED lighting application on vehicle. This design scheme has successfully produced an efficient thermal module to control the LED chip temperature below safety limit.

[1]黃國長，"高亮度 LED 之熱模擬分析探討"，2007年。
[2]Philips Lumileds Lighting, U.S. LLC., "Power Light Source LUXEON III Emitter", Technical Datasheet DS45, www.lumileds.com.
[3]陳智禮，揚鈞杰，"高功率LED的散熱處理"，工業材料雜誌，231期，139-145頁，2006年。
[4]曾俊洲，"發光二極體業之現況與展望"，台灣經濟研究院產經資料庫，2008年。
[5]郭子菱，"前車燈應用加速車用LED 市場發展"，光連雙月刊， 22-24頁，2008年。
[6]Steranka, F. M., Bhat, J., Collins, D., and Cook, L., "High Power LED-Technology Status and Market Applications", Phys. Stat. Sol. (a), Vol. 194, Issue 2, pp. 380-388, 2002.
[7]林志勳，"發光二極體產業發展現況與趨勢"，工研院電子報，2009年。
[8]OIDA (Optoelectronic Industry Development Association)，http://www.oida.org/.
[9]王崇岳，"桌上型電腦散熱模組之參數分析"，2005。
[10]Elenbaas, W., "Heat Dissipation Of Parallel Plates by Free Convection", Physica, Vol. 9, pp. 1-28, 1942.
[11]Kraus, A.D., "Analysis and Evaluation of Extended Surface Thermal System", Hemisphere Published, 1982.
[12]Morrison, A. T., "Optimization of Heat Sink Fin Geometries for Heat Sinks in Natural Convection", InterSociety Conference on Thermal Phenomena, pp. 145-148, 1992.
[13]Morega, A. M. and Bejan, A., "Plate Fins with Variable Thickness and Height for Air-Cooled Electronic Modules", Int. J. Heat Mass Transfer, Vol. 37, pp. 433-445,1994.
[14]Bejan, A., Tsatsaronis, G., and Moran, M., "Thermal Design and Optimization", Wiley, pp. 241-256, 1996.
[15]Bar-Cohen, A., Iyengar, M., and Kraus, A. D., "Design of Optimum Plate-Fin Natural Convective Heat Sinks", Journal of Electronic Packaging, Vol. 125, pp. 208-216, June 2003.
[16]Rahnama, Mohammad and Farhadi, Mousa, "Effect of Radial Fins on Two-Dimensional Turbulent Natural Convection in a Horizontal Annulus", International Journal of Thermal Sciences, Vol. 43, pp. 255-264, 2004.
[17]Inaba, T., Watanabe, S., and Yamada, Y., "LED Headlamp Development for Mass Production", SAE TECHNICAL PAPER SERIES, 2008-01-0339.
[18]Neumann, R., Dobrus, V., Popelek, J., Sayers, M., and Kubena, V., "High Efficient LED Headlamp Design-Styling versus Light Performance", SAE TECHNICAL PAPER SERIES, 2007-01-0874.
[19]Hamm, M. and Huhn, W., "Design Claims and Technical Solution Steps Generating the World First Full LED Headlamp", SAE TECHNICAL PAPER SERIES, 2008-01-0337.
[20]Shenzhen Tianci lighting co., LTD, http://www.tcled88.cn/.
[21]Churchill, S. W. and Chu, H. S., "Correlating Equations for Laminar and Turbulent Free Convection from a Vertical Plate", Int. J. Heat Mass Transfer, Vol. 18, pp. 1323-1329, 1975.
[22]Fluent 6.2 User's Guide, Fluent Inc., 2005.
[23]Patankar, S. V. and Spalding, D. B., "A Calculation Procedure for Heat Mass and Momentum Transfer in Three-Dimensional Parabolic Flows", International Journal of Heat Mass Transfer, Vol. 15, pp. 1787-1806, 1972.
[24]Advantech Co., Ltd., http://www.advantech.tw/contact/.
[25]Institute of Chemistry, The Hebrew University of Jerusalem, http://chem.ch.huji.ac.il/.
[26]Tecpel Co., Ltd., http://www.tecpel.com.tw/.
[27]Kikuchi, K., Hamashima, Y., and Kobayashi, Y., "An Approach to Predicting LED Junction Temperatures With Fluid and Thermal Analysis", SAE TECHNICAL PAPER SERIES, 2005-01-0864.
[28]Hella KGaA Hueck & Co, http://www.hella.com/.
[29]Boebel, D. and Weinhold, H., "Signal Image in PES Systems", Proceedings of the PAL Symposium, pp. 49-55, 2001.
[30]Cree, Inc.,Cree XLamp XP-G LEDs Data Sheet, www.cree.com/xlamp/
[31]李龍育，"高功率LED汽車頭燈散熱設計之模擬與實驗整合研究"，國立台灣科技大學機械工程研究所碩士論文，2008年。
[32]Incropera, P. F. and Dewitt, P. D. "Fundamentals of Heat and Mass Transfer", 4th Ed., John Wiley & Sons, New York, 1996.
[33]Lienhard, J. H. Ⅳ and Lienhard, J. H. Ⅴ, "A Heat Transfer Textbook", 3rd Ed., Cambridge, Massachusetts, U.S.A., 2001.
[34]許益銑，"LED 車頭燈之數值與實驗整合研究"，國立台灣科技大學機械工程研究所碩士論文，2008 年。
[35]KOWE INTERNATIONAL FILM & TV BUSINESS NETWORK, http://www.kw2007.com.cn.
[36]Philips Lumileds Lighting, http://www.philipslumileds.com/.
[37]財團法人車輛研究測試中心(Automotive Research & Testing Center), http://www.artc.org.tw/.
[38]林伯希，"LED 汽車頭燈設計關鍵因素探討"，開南大學企業與創業管理學系研究所碩士論文，2010 年。
[39]Pro/ENGINEER 3.0 User's Guide, PTC, 2008.
[40]KOITO MANUFACTURING CO. LTD., "Light Emitting Module and Lamp", U.S. Patent No. US 2005/0157508 A1, 2005.
[41]KOITO MANUFACTURING CO. LTD., "Vehicle Headlamp", U.S. Patent No. US 2007/0025117 A1, 2007.