自LED微型投影機產品問世後，許多電子產品均試圖內建LED微型投影機來吸引消費者。但受限於LED封裝材料與特性，操作溫度需控制在晶片能承受的範圍內，因此與其它電子產品作整合之前，必須先將LED微型投影機散熱模組作最佳化之設計。本研究先對原型投影機進行鰭片間距最佳化、外殼材質之選用及均溫設計，再將模擬分析之最佳參數用於第一代投影機散熱設計上。從數值結果顯示，第一代投影機在體積縮小約20%之情形下，已能於自然對流散熱設計中，將LED接觸面溫度從130℃降低至67.6℃，且高溫之晶片也能獲得有效的改善；而強制對流方案則沿用自然對流之Heat Sink與外殼模型，挑選合適之風扇以及設計最佳進氣路徑後，已成功將第一代投影機(2.75W)強制對流機型的LED接觸面溫度降低至66.7℃。
另外，基於各階層消費者之考量，在引進工業設計後接著設計第二代投影機的散熱設計，並將其分為無噪音型與高效能型。而第二代投影機之無噪音型尺寸較第一代投影機減少30%的情形下，經鰭片間距最佳化設計以及開孔率之調整進行分析後，其散熱模組已能處理4W之LED輸入功率，並將LED接觸面溫度控制在安全限度內(70℃以內)；而高效能之強制對流散熱型投影機在體積增加約60%後，藉由數值分析針對出入風口與開孔位置作規劃設計，接著再進行2510風扇與Heat Sink作系統化的參數分析，最後藉由CNC技術製作第二代LED微型投影機之強制對流散熱模組與實體模型，並將其實機測試與模擬數據比對以驗證其準確性。值得一提的是，第二代投影機之高效能型散熱模組已能於LED實際輸入功率6W情形下，將LED接觸面溫度降至68.7℃。綜合歸納來說，本研究所建立之散熱模組設計流程，能有系統且嚴謹地完成微投影機的散熱設計，且經實驗證實能解決LED微投影機的散熱問題。

This research focuses on developing the thermal designs of several. This research focuses on developing the thermal designs of several LED pico projectors for different sizes and various heat-dissipating alternatives. At first, a sample projector is chosen to perform CFD simulation and experimental measurement for validating the numerical tool established here. Also, the calculated flow patterns and temperature distributions are visualized and used to generate ideas for upgrading its thermal-management capability. Thereafter, a comprehensive parametric study on heat sink, cover material, and heat-spreading plate is performed successfully to reduce LED temperature from 130℃ to 64℃, which is under the safety temperature limit 70℃. Next, with the aids of the aforementioned experience and a series of CFD simulations, two projector prototypes are developed, fabricated, and tested for meeting customers’ light-weight and high-brightness needs, respectively. Also, both passive and active heat-transfer strategies are considered for each projector to yield the noiseless or the high-performance models. Note that the light-weight version is compacted with a 30% size reduction and the function-oriented version is expanded with a 60% size enlargement compared to the volume of sample projector. Thereafter, heat sink optimization, airflow-path redesign, ventilating-hole addition, and choosing fan size and installing location are implemented on the thermal design via an in-depth CFD simulation and analysis.
As a result, the comparisons between on-board test and the numerical calculation indicate an acceptable temperature deviation within 1.1℃ for all the projector designs considered in this study. Moreover, the noiseless compact projector can operate safely around 70℃ with a 4W LED power input and under the 30℃ environmental temperature. Also, the high-brightness projector functions normally with a 69.9℃ LED temperature and 6W power input. Consequently, this established design scheme successfully generates several thermal modules to control the LED chip temperature below the safety limit for various projector sizes and different cooling approaches. In conclusion, the accomplishment of this research offers a rigorous and systematic design scheme for the thermal management on the LED pico projector.

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