臺灣博碩士論文加值系統

近年來LED發光效率逐漸提升，應用的產品也由傳統指示燈轉變為背光照明用途。由於LED的接面溫度限制較低，故熱量多以傳導與對流形式向外釋出。隨著驅動電流的增加，LED封裝形式的熱管理也逐漸受到重視。而建立一條暢通的散熱途徑，可維持LED接面溫度在容許的範圍內，以確保元件的可靠度。
本研究使用有限體積分析軟體Flotherm對高功率LED模擬熱場分析，分別探討Luxeon LED內部Slug面積與厚度間之關係及四種PCB基板對整體散熱效益之影響。結果顯示，欲將接面溫度降至120℃以下，1W與2W的LED所需Slug面積不得小於25、70mm2。而厚度在2~4mm時有較低的熱阻值。簡化介電層層數與使用高導熱性銲錫取代導熱膠能有效改善溫度變化劇烈的現象，有效提昇散熱效益。實驗部份紀錄LED重複啟動後，在固定電流400mA的條件下，紅光電壓下降0.4V，晶片表面上升6.2℃；綠光電壓下降0.4V，晶片表面上升9.1℃。

Light Emitting Diodes (LEDs) have progressed from being indicators to general and back lighting applications in recent years due to increase of their emitting efficiency. LED junction temperatures are considerably lower than those of light bulbs and hence the heat transfer mechanism depends on conduction and convection primarily. With the increased electrical currents, the thermal managements have been focused in developments of LED packaging. A good thermal path can help an LED chip to OK its junction temperature low to maintain the reliability of LED.
A finite volume method package (Flotherm) is used to analyze the temperature field of the high power LEDs. Both package and system level thermal managements are discussed. The junction temperature of 120℃ can be obtained. Packages with the slug of 25 and 70 mm2 in cross sectional areas, 2~4mm thick for 1W and 2W’s LED, respectively, with the same cooling system. By removing the dielectric layers and using solder in place of epoxy can lower the junction temperature. Experimental results show that the voltages of the red and green LEDs decrease 0.4 Volt with a fixed current of 400mA. The surface temperatures of the red and green LED increase 6.2℃ and 9.1℃.

表目錄 IV
圖目錄 V
第一章 序論 1
1-1前言 1
1-2研究動機 2
1-3文獻回顧 4
第二章 理論基礎 10
2-1 LED構裝圖 10
2-2 LED的熱傳路徑 11
2-3 熱阻基本定義 12
第三章 實驗方法與設備 15
3-1實驗方法 15
3-2實驗設備 15
3-2-1電源供應器 15
3-2-2熱電偶溫度擷取系統 16
3-2-3電壓擷取系統 16
3-2-4絕熱環境 17
3-2-5固定電流源 17
3-3實驗模型 17
3-3-1 LED晶片 18
3-3-2 散熱膏 18
3-3-3 鋁塊(Heat Sink) 18
第四章 數值模擬 20
4-1熱設計流程 20
4-2 Flotherm軟體介紹 20
4-2-1數學分析模式 21
4-2-2系統環境參數 23
4-3材料性質之設定 26
4-3-1材料參數設定 26
4-3-2 熱源參數設定 27
4-4數值模型介紹 27
第五章 結果與討論 30
5-1熱設計需求及目標 30
5-2 LED內部Slug面積與厚度間之關係 31
5-2-1完整與簡化的LED模型之比較 31
5-2-2 LED發熱瓦數為1W之情況 32
5-2-3 LED發熱瓦數為2W之情況 35
5-3 各類型PCB基板對整體散熱效益之影響 36
5-4 LED特性實驗 40
第六章 結論 43
參考文獻 45

[1] Mehmet Arik, James Petroski, and Stanton Weaver, “Thermal Challenges in the Future Generation Solid State Lighting Applications: Light Emitting Diodes”, 2002 Inter Society Conf. On Thermal Phenomena, pp. 113-120, 2002
[2] James Petroski, “Thermal Challenges Facing New Generation Light Emitting Diodes (LED ) for Lighting Applications”, Solid State Lighting II, Proc. of SPIE, Vol. 4776, pp. 215-222, 2002
[3] F. M. Steranka, J. Bhat, D. Collins, L. Cook, M. G. Craford, R. Fletcher, N. Gardner, P. Grillot, W. Goetz, M. Keuper, R. Khare, A. Kim, M. Krames, G. Harbers, M. Ludowise, P. S. Martin, M. Misra, G. Mueller, R. Mueller-Mach, S. Rudaz, Y.-C. Shen, D. Steigerwald, S. Stockman, S. Subramanya, T. Trottier, and J. J. Wierer, “High Power LEDs – Technology Status and Market Applications”, phys. stat. sol. (a) 194, No. 2, pp. 380–388 ,2002
[4]劉如熹, 紀喨勝, “紫外光發光二極體用螢光粉介紹,” 全華科技圖書股份有限公司, 92年11月初版
[5] Frank Wall, Paul S. Martin, Gerard Harbers,” High Power LED Package Requirements”, Third International Conference on Solid State Lighting, Proc. of SPIE, Vol. 5187, pp.85-92, 2004
[6] OIDA, “Light Emitting Diodes (LEDs) for General Illumination”, An OIDA Technology Roadmap Update 2002
[7] Technical Datasheet DS25, “Power Light Source Luxeon Emitter”, www.lumiled.com
[8] Eugene Hong, Nadarajah Narendran, “A Method for Projecting Useful Life of LED Lighting Systems”, Third International Conference on Solid Lighting, Proceedings of SPIE, Vol. 5187, pp. 93-99, 2004
[9] Nadarajah Narendran, Yimin Gu, Jean Paul Freyssinier, H. Yu, L. Deng, “Solid-state Lighting: Failure Analysis of White LEDs”, Journal of Crystal Growth, Vol. 268, pp.449–456, 2004
[10]黃振東, “LED封裝及散熱基板材料之現況與發展”, 工業材料雜誌 , 231期, pp. 70-81, 2006
[11]陳智禮, 楊鈞杰, “高功率LED的散熱處理”, 工業材料雜誌, 231期, pp. 139-145, 2006
[12]張志祥, 邱國創, 林澤勝, “LED封裝模組與產品應用近況發展介紹”, 工業材料雜誌, 229期, pp. 69-84, 2006
[13] Y.B. Acharya, and Vyavahare, "Temperature Characteristics of the Device Constant (n) of a Light Emitting Diode", Solid State Electronics, Vol. 43, pp. 645-647,1999
[14] Mahbub Akhter, Pleun Maaskant, Declan Casey, James Rohan, Nicolas Cordero and Brian Corbett, “Packaging Technology for High Power Blue-Green LEDs”, Proc. of SPIE, Vol. 5825, pp. 634-639, 2005
[15] Shatil Haque, Dan Steigerwald, “Packaging Challenges of High-Power LEDs for Solid State Lighting”, www.LUXEON.com
[16] Nadarajah Narendran and Yimin Gu, ”Life of LED-Based White Light Sources”, Journal of Display Technology, IEEE/OSA, Vol. 1, No. 1, 2005
[17] James Petroski, ” Spacing of High-Brightness LEDs on Metal Substrate PCB's for Proper Thermal Performance”, Inter-Society Conference on Thermal Phenomena, IEEE, pp. 507-514, 2004
[18] Gwo-Jiun Sheu, Farn-Shiun Hwu, Shen-Hang Tu, Wen-Tung Chen, Jenq-Yang Chang, Jyh-Chen Chen, ” The Heat Dissipation Performance of LED Applied a MHP”, Fifth International Conference on Solid State Lighting, Proc. of SPIE, Vol. 5941, pp. 594113-1 ~ 8, 2005
[19] Mehmet Arik and Stanton Weaver, ” Effect of Chip and Bonding Defects on the Junction Temperatures of High-Brightness Light Emitting Diodes”, Optical Engineering, SPIE, Vol. 5530, pp. 111305, November 2005
[20] Zetao Ma, Xiaojun Wang , Daqing Zhu , and Sheng Liu, “ Thermal Analysis and Modeling of LED Arrays Integrated With an Innovative Liquid-cooling Module”, 6th International Conference on Electronic Packaging Technology, IEEE, pp. 542-545, 2005
[21] Mehmet Arik, Charles Becker, Stanton Weaver, and James Petroski, “Thermal Management of LEDs: Package to System”, Third International Conference on Solid State Lighting, Proc. of SPIE ,Vol. 5187, pp 64-75, 2004
[22] Lalith Jayasinghe, Yimin Gu, and Nadarajah Narendran, “Characterization of thermal resistance coefficient of high-power LEDs”, The International Society for Optical Engineering, Proceedings of SPIE, Vol. 6337, pp. 63370V-1~10, 2006
[23] H. Rainer, “Thermal Management of Golden Dragon LED”, http://www.flotherm.com, 2002
[24] LUXEON Thermal Design Guide, “Thermal Design Using Luxeon Power Light Sources”, www.lumiled.com
[25] Reference Design RD25, “Luxeon Reliability”, www.lumiled.com
[26] F. S. Tse and I. E. Morse, “Measurement and Instrumentation in Engineering”, Marcel Dekker, Inc, 1989
[27] B. E. Launder and D. B. Spalding, “The Numerical Computation of Turbulent Flows”, Appendix D of Computer Methods in Applied Mechanics and Engineering 3, North-Holland Publishing Company, pp.269-289, 1974.
[28] Rao R. Tummala, “Fundamentals of Microsystems Packaging”, The McGraw-Hill Companies, Inc.
[29]陳信文, “電子構裝技術與材料”, 高立圖書有限公司, 2004
[30]紀國鐘, “發光二極體及其應用”, 工業技術研究院工業材料研究所, 1991
[31]陳建隆, ”發光二極體之原理與製程”, 全華科技圖書股份有限公司, 95年初版
[32]黃歆斐, 周榮華, “高亮度LED封裝之熱分析”, 中華民國力學學會第三十屆全國力學會議, pp. 112, 2006