【正文】 .................................................................. 2 課題來源 ............................................................ 2 課題的提出 .......................................................... 2 課題的目的和意義 .................................................... 3 國內(nèi)外大功率 LED 散熱研究 .............................................. 3 市場與應用前景 ........................................................ 5 本文的主要研究內(nèi)容 .................................................... 6 本章小結 .............................................................. 6 2 大功率 LED 的基礎理論 ...................................... 7 LED 的簡介 ............................................................ 7 LED 的結構 .......................................................... 7 LED 的發(fā)光機制 ...................................................... 8 LED 的主要性能參數(shù) .................................................. 9 熱效應對 LED 的影響 ................................................... 11 LED 熱效應對 PN 結正向偏壓的影響 .................................... 11 LED 熱效應對發(fā)光效率的影響 ......................................... 11 LED 熱效應對光能量的影響 ........................................... 12 LED 熱效應對光色的影響 ............................................. 12 LED 熱效應對壽命的影響 ............................................. 12 本章小結 ............................................................. 12 3 大功率 LED 熱分析基礎理論和通用軟件 ANSYS 簡介 ............... 13 LED 散熱基礎知識 ..................................................... 13 有限元理論簡介 ....................................................... 15 通用有限元軟件 ANSYS 介紹 ............................................. 15 本章小結 ............................................................. 17 4 LED 有限元模型熱場仿真分析 ................................ 18 LED 燈具封裝模型的建立 ............................................... 18 LED 燈具封裝穩(wěn)態(tài)溫度場及應力場分析 ................................... 19 5 LED 的封裝結構優(yōu)化設計 .................................... 22 優(yōu)化設計介紹 ......................................................... 22 優(yōu)化設計的基本概念 ................................................. 22 優(yōu)化設計問題的數(shù)學表述與步驟 ....................................... 24 APDL 參數(shù)化語言 ...................................................... 25 大功率 LED 的封裝結構優(yōu)化設計 ......................................... 25 芯片溫度最低 ....................................................... 25 結構最輕 ........................................................... 26 應力最小 ........................................................... 28 本章小結 ............................................................. 29 6 結論 .................................................... 30 全文總結 ............................................................. 30 全文展望 ............................................................. 30 謝辭 ...................................................... 31 參考文獻 ................................................... 31 附錄 ...................................................... 33 第 1 頁 共 38 頁 引言 眾所周知， 隨著全球能源的緊缺以及全球氣候變暖，在新的能源開發(fā)沒有取得突破性進展的情況下 ，能源的節(jié)約利用成了世界各國思考的重大問題，其僅照明耗電量大約占世界電量消耗量的 20%。 FEM analysis。 關鍵詞 ： 大功率 LED； 散熱 ； 有限元模擬； ANSYS； 結構優(yōu)化 Abstract The method of 3D Parametricmodeling by APDL language is pointed out for some LED in this paper. This work is based on a lot of references and many theories about parametric modeling, and structural optimization. Furthermore, the structural optimization for the LED is finished after a series of work including the analysis of the temperature gradient and the stress gradient. In this paper, the thermal analysis of package products in a highpower white LED light fitting was investigated in this paper. According to the FEM calculation, the static temperature field in the working process was analyzed. The temperature gradient in the LED package structure was found. Ceramic substrate and heatsink base were considered as the main part to block heat dissipation. Therefore, several optimization designs of LED were put forward, and their simulation results were analyzed simply. The optimization of this article can be chosen from the three aspects of the LED package structure for optimal design. The first kind of circumstances: the objective function was chip temperature, and constraint condition was each size range. There was the optimization in the seventh time. From the best series, it can be seen that the highest temperature of chip has fallen to degrees Celsius than before, and optimized nearly 20% lower. The second kind of circumstances: the objective function was weight of structure. When optimizing weight of structure, constraint condition was also each size and the chip temperature was taken state variables. After 13 times, it achieved to convergence. There was the optimal in the first 10 times, weight values was . The third kind of circumstances: the objective function was the Von Mises stress. When optimization objective was packaging stress, constraint condition was the size range and state variables were respectively weight of structure and temperature of chip. The maximum stress was and was lower by % than that before the optimization. Key words: Highpower LED。 對結構重量優(yōu)化時，約束條件為各尺寸的范圍，狀態(tài)變量取芯片溫度。由最佳優(yōu)化系列可以看出，芯片的最高溫度已降至 ℃，比優(yōu)化前降低了將近 20%。 為此，提出幾種 LED 的優(yōu)化方案，并進行了簡單分析。編號： 畢業(yè) 設計說明書 題 目： 大 功率 LED 器件的封裝 結構優(yōu)化設計 題目類型 ： ?理論研究 ?實驗研究 ?工程設計 ?工程技術研究 ?軟件開發(fā) 摘 要 本文以某大功率 LED 為背景，在查閱國內(nèi)外大量文獻的基礎上，經(jīng)過對各種參數(shù)化建模和優(yōu)化技術方法的探索和研究，提出了直接在有限元平臺上利用 APDL 語言進行其溫度場和應力場分析的基礎上 ，對該 LED 結構參數(shù) 優(yōu)化設計。 本文中， 針對一種 功率半導體器件 —— 大 功率 LED 照明燈具的封裝與組件進行散熱設計，通過有限元模型，分析其在工作狀態(tài)時的穩(wěn)態(tài)溫度場分布，發(fā)現(xiàn) LED 封裝整體的溫度梯度比較大，而封裝陶瓷基板 和熱沉基座 是阻礙器件散熱的主要部分。 本文的優(yōu)化設計可從三個方面對所選用的 LED 進行封裝結構優(yōu)化設計： 第一種情況：優(yōu)化目標為芯片溫度， 約束條件為各尺寸的范圍，在第 7 次達到優(yōu)化。 第二種情況：優(yōu)化目標為結構重量 。經(jīng)過 13 次后收斂，在第 10 次時最優(yōu)，重量值為 ； 第三種情況：優(yōu)化目標為 Von Mis