利用有限元素分析法於發光二極體熱傳遞分析

A study of thermal transmission for LED by finite element method

吳宏琦(Hung-Chi Wu)

指導教授 ： 翁豊在

國立虎尾科技大學/工程學院/機械與機電工程研究所/碩士(2011年)

https://doi.org/10.6827/NFU.2011.00036

摘要

發光二極體(LED)要使用在替代光源上除了必須提高亮度外，另一方面則須同時使用多顆發光二極體。LED光源約有15%~20%可轉換成可見光，其餘80%~85%全部轉換成熱。因此，當外部取光效率以及發光二極體結構對於熱的問題尚未有明顯的突破前，發光二極體的熱管理就顯得相當的重要。由於發光二極體其晶片在額定負載時會產生高溫，為了避免熱量累積會導致晶片出光效率降低進而降低晶片性能，通常在基板連接端會配置一散熱裝置，以提高熱傳遞效率達到散熱效果。
本研究目的為發光二極體封裝前與封裝後之熱傳遞途徑分析，研究中利用有限元素分析軟體ANSYS Multiphysics v11.0求解計算流體力學(Computational fluid dynamics, CFD)，探討LED封裝前之銀膠(Silver epoxy)厚度與幾何對於晶片溫度影響，以及封裝後外部散熱器(Heat sink)之幾何其熱傳效能優劣，以獲取散熱器各部最佳參數。

關鍵字

發光二極體 ； 計算流體力學 ； 銀膠 ； 散熱器

並列摘要

There’re two keys to utilize LED as replacement light energy; one is to increase the chipset brightness, while another is to use LED arrays instead of single LED. Around 15 to 20% of LED illuminant will be transformed to visible light, while up to 85% of the LED illuminant will be transformed to heat. Therefore, before there’s obvious breakthrough on LED constructions to heat, thermal management of LED is relatively important. As a result of chip will produce high temperature of LED under full load at nominal current. For the purpose of heat accumulation can be decrease the efficiency of chip, we will set a heat spreader to increase thermal conduction and enhance thermal performance efficiency under the substrate normally.
The purpose of this study is to analysis heat transport path both before and after packaging. In this article, we used finite element analysis software(ANSYS) to solve computational fluid dynamics, we explore the influence of thickness and geometry of silver epoxy and the geometry of external heat spreader on the chip temperature before and after packaging, respectively.

並列關鍵字

LED ； Computational fluid dynamics ； Silver epoxy ； Heat sink

參考文獻

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