近年來，由於全球能源危機，加上環保意識抬頭，使得固態照明之發光二極體（LED），成為照明領域上的新光源。隨著高亮度的白光LED誕生，使得車前燈逐漸開始運用LED做為其光源，包含近遠燈、霧燈及晝行燈。但因車前燈位於引擎室附近，而汽車引擎室的環境溫度高達80℃以上，過熱的溫度會造成LED發光效率的下降及使用壽命的縮短，如何設計一高效能的散熱系統，將是LED車前燈在應用上必須克服的問題。
本研究藉助實驗及模擬探討LED汽車頭燈上的熱傳特性，以LED基板溫度（Tb）變化，討論LED散熱方式的熱傳導效益，使晶片維持在固定的操作溫度下，以維持燈具的可靠度。本研究針對原始LED頭燈以實驗的方式，在不同的環境溫度（30℃、50℃、80℃）下，量測LED基板溫度（Tb）並觀察其溫度變化。當環溫80℃時，LED 基板溫度（Tb）超過設計限制（100℃），故需設計一熱交換器將燈具內高溫與外部環境進行熱交換，並運用流場來增加其散熱效能。改善部分運用模擬分析進行，其改善方法為以下三種：裝置外部散熱鰭片、裝置外部散熱鰭片搭配空氣導流道、裝置外部散熱鰭片搭配熱管及空氣導流道。由模擬結果可得知，在80℃高溫環境下，僅靠散熱鰭片以自然對流的方式進行散熱，其效果有限，必須搭配熱管迅速的將熱從燈具內帶出，並均勻的分布在鰭片基座上，接著利用空氣導流道將引進的冷空氣吹向散熱鰭片，將LED Tb降至設計限制（100℃）以下，以達到散熱的目的。

Recently, due to the world's energy crisis and people's awareness of environmental protection, the Light Emitting Diode has become a new light source. Since the appearance of hight brightness white light LEDs, the automobile industry has adopted the LED as it's light source, including headlamp, foglamp, and day runnig light. However, because the frontlight is close to the engine and can be in an enviroment with temprature nearly 80℃. That is, this high temperature may decrease luminous efficiency and shorten the life span of the LED. Therefore, how to design a high- efficient thermal system is an issue which have to be thought thoughtfully and solved.
This study uses ANSYS simulation and experiments to explore the heating characteristics of headlamp and the change in temperature of the LED substrate. The goal is to improve the heat transfer efficiency to maintain the chip's working temperature and reliability of the lamp.This study starts by examing the heat transfer performance of an original LED headlamp from a maunfacturer, using bith simulation and experiments. The environmental temperature is set at 30℃, 50℃, and 80℃, respectively. The temperature of the LED substrate is used as an indicator. When the enviroment is at 80℃must be proved the temperature of the LED substrate is out of specification (100℃). Thus a heat exchanger must be provided with the outside enviroment in order to exchange the heat inside the lamp with the outside enviroment. The improvements includes: heat sink, heat sink with guided channel for air, and a heat sink with a heat pipe and air channel. The simulation results show that the design with a heat sink and heat pipe and air channel can achieve the thermal design goal to keep the LED substrate temperature below 100℃.

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