高功率LED陶瓷燈具內散熱基板形狀之熱傳分析

A Thermal Analysis of Substrate to High Power LED in a Ceramic Lamp

本文之研究分別利用 CFD 數值模擬軟體和實驗的方法，針對陶瓷燈具內LED 晶片與散熱基板的材質與幾何形狀對熱傳之影響進行研究。本研究以紅外線熱影像儀量測燈具內LED 晶片與散熱基板的溫度分佈，並將此量測結果與CFD軟體之數值計算所求得結果之誤差值在3.9%之內。本文之研究結果顯示，散熱基板之幾何形狀對於本文所使用之陶瓷燈具具有影響，接面溫度 （Tj） 的上升與散熱基板的面積增加以及基板的厚度與材質熱傳係數的上升有關。然而更換更高之材料係數對於溫度的下降並不明顯，可能原因為陶瓷材料熱阻所造成之現象。

In this paper, a thermal phenomenal was studied through both CFDsoftware package and experiments. The thermal performance was simu lated using the CFD software by varying the substrate and geometry of theceramic seat in an LED lamp. The temperature distributions of theceramic seats were also measured using a thermal imager. The CFDsimulated results agreed well with the measured data and the deviation waswithin 3.9%.The junction temperature (Tj) of an LED lamp is related directly to thesubstrate geometry. The junction temperature will decrease as the area ofspreaders, the thickness or the thermal conductivity of the substrateincrease. However, high thermal conductivity doesn’t cause a significantdecline in temperature due to the high thermal resistance of ceramic.