不同表面製程應用於LED背光模組散熱之研究

The Research of Different Surface Treatment Applied for LED Backlight Heat Dissipation

林盈宏(Ying-Hung Lin)

指導教授 ： 蘇程裕

國立臺北科技大學/機電學院/製造科技研究所/碩士(2013年)

摘要

金屬燈罩為LED背光模組散熱途徑中一關鍵元件，其高亮度LED所產生的高熱量若無法適時導出，則會影響LED壽命，但因空間限制無法設計成鰭片型式。
本研究目的在探討不同的表面製程處理，應用在LED背光模組金屬燈罩表面，分析其散熱效能。研究中配合MCPCB LED bar，設計出面積適中的鋁合金燈罩，共使用微弧氧化、電漿熔射、碳化矽、氧化鋁及氧化矽噴塗等五種表面製程處理及原素材Al-5052共六種燈罩。配合背光模組點亮LED bar後，使用接觸式熱電耦及非接觸式熱影像儀觀察並比較不同的表面處理，分析LED Tj (Junction temperature)的溫度變化及熱傳導到LED燈罩表面的散熱效能。
研究結果顯示，塗覆後燈罩經由熱電偶測試結果與原素材Al-5052比較得知，LED Tj降溫速度最快者為氧化矽與碳化矽噴塗，其次為微弧氧化，最差者為電漿熔射，但即使是最差的電漿熔射也有3.6%的散熱改善效率；經由熱阻值測試結果得知微弧氧化與電漿熔射鋁的熱阻值比原表材僅微幅增加，最差者為碳化矽噴塗；在熱影像圖片中觀察顯示 表面塗覆後表面均溫效果較佳者為微弧氧化、碳化矽與氧化矽，最差者為電漿熔射鋁。

關鍵字

LED ； 微弧氧化 ； 電漿熔射 ； 氧化鋁/氧化鈦 ； 散熱 ； 陶瓷

並列摘要

LED metal holder is a key component for heat dissipation on LED backlight unit. The LED life will be reduced by design without efficient dissipation. However, due to the limited space in backlight unit, the dissipation mechanism can’t be adopted with normal methodology as fin.
The purpose of this research is to discuss different surface treatment applied on LED metal holder and analyze the dissipation performance of each process. This research adopts LED/MCPCB type light bar, and aluminum LED holder processed with Micro-Arc Oxidation、Plasma Spray、SiC、Al2O3、SiO2 coating and Al-5052. The procedure for this analysis is to light on back light unit, then use contact thermocouple and non-contact thermo video device to detect and measure the change of LED Tj (Junctiion temperature). Based on the test data of LED Tj, then analyze the heat conduction performance for each surface treatment material.
The study shows that the best heat conduction performance on LED Tj is coating with SiO2 and SiC, following with Micro-Arc Oxidation , and Plasma Spray comes to the last. However, even coating with Plasma Spray, the backlight unit heat dissipation still have 3.6% improvement. Also, from heat resistance test data, the resistance value has little increase on coating with Micro-Arc Oxidation and Plasma Spray, SiC has least increase on resistance value. On the other hand, the thermo image shows that the best effect with average temperature on the surface is coating with Micro-Arc Oxidation、 SiC and SiO2, the last is Plasma Spray.

並列關鍵字

Micro-Arc Oxidation ； Plasma Spray ； Alumina/Titania ； Heat dissipation ； Ceramic

參考文獻

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