高功率多晶粒發光二極體封裝之設計開發

Design and Development of High Power Multi-chip LED package

張銘利(Ming-Li Chang)

指導教授 ： 陳文瑞

國立虎尾科技大學/電機資訊學院/光電與材料科技研究所/碩士(2011年)

摘要

近年來全世界都在開發發光二極體的光源，尤其是用於一般照明、顯示器背光源或車用照明等等都是目前熱門的題材。本論文主要是以探討照明光源為設計導向，市面上常見的光源裝置，大多是以大功率發光二極體晶片設計主軸，但目前大功率晶片其外部量子效率不佳，因單顆操作瓦數較高，導致晶片本身產生之熱容易累積，故熱源溫度也偏高，但一般發光二極體的封裝設計，其結點溫度都會盡量控制低於70oC以下，故使用高功率晶片的同時，更必須於後端散熱片下更多工夫，相對的其成本也較高。
本篇研究聚焦在發光二極體的面光源設計與驗證，利用一基板與多數成陣列式排列發光二極體晶片設置於該基板上，使用小尺寸晶片(280~500微米之間)，並且控制晶片間距及基板厚度。結果是在每兩發光二極體晶片之間的間距為該晶片邊長尺寸的2倍以上時，熱阻降低將會趨緩，再增加間距對於溫度的降低已無明顯之差異。另外對於多晶發光二極體的承載基板，經實驗驗證當基板隨著厚度增加熱阻降低，但厚度在2毫米以上時熱阻降低呈趨緩狀態，然而基於成本考量，目前市面上鋁基板及銅基板皆是以1.0~2.0毫米為主力產品。最後依據熱模擬驗證結果，如能將散熱板溫度控制在60度以內，信賴性基本上可以達到通過美國能源之星之要求，亦即在25000小時內，光衰低於30%以內之壽命規範要求。

關鍵字

發光二極體

並列摘要

In recent years, the development of LED light sources was carried out all over the world. Especially for general illumination, backlighting of the monitor or automotive lighting is by far the most popular themes. This paper is primarily a study on lighting design. The common light sources on the market are mostly designed by high power LED chips. However, the external quantum efficiency of the present high power LED chip was poor. Because the operation power is higher than before, such that the generated heat can be easily accumulated and that the temperature of heat source is also higher than before. For the general LED packaging design, the junction temperature can be well controlled less than 70oC if possible. At the same time, more tasks must be used in the back-end heat sink, and its costs are also high.
This study focused on the LED light source design and verification, using a base substrate and arranged most of an array type LED chips set onto the substrate. By using the small-size LED chips (between 280~500 microns), the substrate thickness and chip spacing are well controlled. It was found that the space between every two LED chips is twice times above the size of the chip. The thermal resistance will have a slowing down rate. The temperature reduction is less obvious when the additional space was given. In addition, the multi-chip LED submount was verified by the experiment. We found the thermal resistance decreased by increasing the thickness of submount. The reduction of thermal resistance is slowing down while the thickness is increasing over 2mm. However, based on cost effective, current copper and aluminum plate was commercially available with a thickness of 1.0~2.0 mm. Finally based on the thermal simulation results, if the temperature of heat sink can be controlled within 60oC, the reliability can be achieved pass through the United-States-Energy-Star requirements, or 25,000 hours, that is, the optical attenuation of life requirement is less than 30%.

並列關鍵字

LED

參考文獻

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