銅散熱光杯之取光結構於高效率發光二極體之應用

Thermal Dispersed Copper Cup Design of Light Extraction for High Power LEDs Array Modules Applications

洪瑞華(R. H. Horng) ； 江鎰禎(I. C. Chiang) ； 林瑞欽(R. C. Lin) ； 胡鴻烈(H. R. Hu) ； 唐力紳(L. S. Tang) ； 武東星(D. S. Wuu) ； 許振鵬(C. P. Hsu)

《光學工程》 115期 (2011/10) Pp. 27-32

https://doi.org/10.30011/OE.201110.0005

摘要

本研究採高散熱效能的銅光杯結構用於高功率LED的封裝，LED晶粒則設計具有斜角的藍寶石基板以提高元件的的取光效率；LED晶粒的斜角化基板結構經由光學計算後，斜角角度爲75°時，具有37.16%的光取出率，光學模擬之結果也顯示斜角化基板的出光角度爲125°，比傳統基板出光角度大10°；根據模擬結果設計並製造的高散熱及高取光率的LED元件，斜角基板係使用化學機械研磨的方式，將LED晶粒基板的角度研磨約爲75°，銅光杯則使用黃光微影、真空鍍膜與電鍍銅製程，完成具有高散熱及高反射鏡面的銅光杯，由電子顯微鏡觀察LED的剖面形貌，可發現LED晶粒與銅光杯緊密結合；此LED元件經光場量測得知，斜角化基板的光場以及正向光皆有明顯提升，與模擬結果的趨勢相符合；光輸出功率量測結果顯示，斜角化基板的LED晶粒使用銅光杯封裝後，在注入電流爲350mA時輸出功率爲395.6mW，發光效率爲33.2%，使用銅光杯封裝無斜角化基板的光功率爲372.6mW，發光效率爲26.4%，無斜角化基板的傳統封裝結構LED的光功率爲325.4mW，發光效率20.8%，此結果顯示，銅光杯的高散熱效果使LED的效率由20.8%提升至26.4%，而改善出光率的斜角化基板結構，也讓LED的發光效率再提升至33.2%。

關鍵字

銅光杯 ； 斜角基板 ； 發光二極體

並列摘要

In this study, beveled substrate and cup-shaped copper sheet were used to fabricate high power LEDs. The LED chip with beveled substrate was designed to improve light extraction. The light extraction of 37.16% was obtained with beveled angle of 75° via optical simulation. The result of simulation was also indicated that the light extraction angle is 125° higher than original substrate LED device. The high light extraction LED device was designed and fabricated based on the result of optical simulation. The beveled substrate with 75° beveled angle was polished using chemical mechanical polishing. The photolithography, vacuum deposition and electroplating were adopted to finished the cup-shaped copper sheet which have high thermal dissipation and high light extraction. The cross section image shows that the LED chip and cup-shaped were contact rigid measurement by scanning electron microscope. The LED device with beveled substrate has large luminous flux which was conform to the result of simulation. The output power and power efficiency were 395 mW and 33.2% (@350 mA), respectively of LED device using cup-shaped copper sheet with beveled substrate. The output power and power efficiency were 372.6 mW and 26.4% (@350 mA), respectively of LED device using cup-shaped copper sheet with original substrate.The output power and power efficiency were 325.4 mW and 20.8% (@350 mA), respectively of original LED device. These results indicate that cup-shaped copper sheet can improved power efficiency from 20.8% to 26.4%. The beveled substrate was to enhance power efficiency even more high.

並列關鍵字

cup-shaped copper sheet ； beveled substrate ； LED