以電泳螢光粉優化白光二極體之演色性

The optimized color rendering index of white LEDs by using the electrophoretic phosphor

李雅婷(Ya-Ting Li)

指導教授 ： 陳文瑞

國立虎尾科技大學/電機資訊學院/電子工程系碩士班/碩士(2013年)

摘要

本論文提出三種方法改善白光發光二極體螢光粉片之演色性，並以電泳沉積法進行實驗製備螢光粉片，第一為電鍍薄金層，第二為混合紅、黃雙色螢光粉，第三為分層電泳沉積螢光粉，分層電泳沉積螢光粉分三種結構進行比較分析。電泳沉積技術係以非水系懸浮溶液，施予外加固定電壓，於陰極基板上沉積一層均勻螢光粉片，為了使螢光粉片得以從陰極基板上完全剝離，先均勻塗佈一層薄矽膠體於螢光粉片之上，爾後以酸蝕反應進行剝離動作，最後將其螢光粉片封裝於高功率藍光LED上進而形成白光。
在電泳沉積後之酸蝕反應時，因酸蝕時間越長會使螢光粉片厚度損失越多，因此可發現在已添加紅色螢光粉之螢光粉片酸蝕實驗中，紅色螢光粉因被酸蝕過多以致形成演色性不足。改善實驗研究結果顯示，比較五種結構之電泳沉積，並量測其封裝後之演色性，以分層電泳沉積結構中的Red-Yellow-Red (RYR)三層結構，具有最佳演色性提升效果。

關鍵字

電泳沉積法 ； 演色性

並列摘要

In this thesis, we propose three methods to improve the color rendering index (Ra) of phosphor plates in white light-emitting diodes (WLEDs). The phosphor plates throughout this thesis were prepared by using the electrophoretic deposition (EPD) technique. The first method is by electroplating a thin gold layer, the second is using the mixed-color (Red and yellow) phosphors, and the third is that the EPD phosphors were deposited layer-by-layer. Three kinds of structures of the layer-by-layer EPD phosphors were performed to compare with other methods. The electrophoretic deposition technique was a non-aqueous suspension solution, and given a constant voltage, thus the phosphor plate was uniformly deposited on the cathode. After that, in order to completely lift off the phosphor layer from the cathode, the thin silicon paste was firstly coated onto the phosphor layer. Then, the acid solution was used to lift off the phosphor plate. In the final, the phosphor plate was packaged with the blue LED die to form the white light.
After the EPD process, in the acid reaction, the more time need to lift off the phosphor plate results in the more lost in thickness of phosphor plate. Therefore, it was found that in the red phosphor plate deposition experiment, the red phosphor will be lost more so the Ra value obtained cannot reach enough. Compared to five structures(method I(1), method II(1), and method II(3)) of EPD deposition and measured its color rendering index of the packaged LED, it is obviously found that the Red-Yellow-Red (RYR) three-layer structure has the best Ra value.

並列關鍵字

Electrophoretic deposition method ； color rendering index

參考文獻

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