電泳螢光粉應用於發光二極體之研究

Study of electrophoretic phosphor applied on light-emitting diodes

白詔安(Jau-An Bai)

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(2009年)

摘要

由前人文獻得知，若要加快實現固態照明的腳步，傳統白光二極體所採用點黃色螢光膠方式，將造成許多不可預測之問題等種種因素，且容易演生出光色不均勻與封裝體可靠度等問題，因此必須被加以改善才能被應用於固態照明上。
本研究使用電泳技術，將黃色螢光粉分散於懸浮於溶劑中，在一外加電壓驅動下，於陰極基板上形成一均勻之粉體層。在製備完成懸浮液後，本實驗藉由改變外加電壓、螢光粉粉體濃度、沉積時間、去離子水比例與不同基板上沉積，探討電泳螢光粉的重量與厚度與施加的電壓、濃度、沉積時間等關係，並且研究去離子水比例的改變對於電解質之影響與不同基板沉積之粉體層是否產生細微結構之變化。
藉由電泳螢光粉之基礎研究，將可得知在外加電壓為200V時，當螢光粉的濃度改變，我們可控制螢光粉沉積厚度約為16至40μm，被藍光LED激發所得之白光色溫可達3800至6000 (K) 之範圍，白光均勻度由色溫之差異值約為80~3000 (K)，而在高色溫的表現上，其因螢光粉厚度與緻密度之關係，差異值將會更大，因此使用電泳法所製作之螢光粉確實可提高白光之均勻度，而且還可提高外部取光效率5 %。另外我們得知其色溫差異量之變化主要由藍光LED之出光量與螢光粉層之緻密度所影響，故未來可著墨於緻密度之改善。

關鍵字

電泳

並列摘要

Literatures about reliability and dispense of LED know, in order to accelerate the development of solid-state lighting, we must overcome the problem made by tradition dispense phosphor gel converted blue light emitting diodes.
In this study, the phosphor particle are uniform dispersed in solvent and then electrophoresis deposition forms uniform deposition on cathode electrode under an apply voltage. After the suspension done, the experiment through changing the parameter condition, such as apply voltage, phosphor concentration, deposition time, DI water percentage and different substrate. We discuss the relationship among the weight and thickness of electrophoretic phosphor and the apply voltage, concentration, deposition time. Besides, we also discuss how the percentage change of DI water could influence electrolyte and whether deposition in different substrate would form the structures’ variation.
In the electrophoretic phosphor basic study, the apply voltage at 200V under the concentration of phosphor varies and then we can controls deposition thickness approximately 16 to 40 micrometer. The white light of phosphor by blue LED emitting correlated color temperature (CCT) to achieve approximately 3800 to 6000 K rages. The white light uniform values define CCT variation. Therefore, the CCT variation value to achieve approximately 80 to 1500 K. The high CCT observed variation value bigger of phosphor thickness and packing density relation. For this reason, the EPD phosphor methods to achieve uniform white light and increase external extraction efficiency than tradition white LED. In addition, we knows CCT variation value to come from blue LED chip light emitter amount and phosphor packing density influence. In the future, the EPD phosphor study can focus improvement phosphor packing density.

並列關鍵字

electrophoretic

參考文獻

參考文獻

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[4] A. Formeto, L. Montanaro, and M. V. Swain, “Micromechanical characterization of electrophoretic-deposited green films,” J. Am. Ceram. Soc., Vol.82, pp. 3251-3528, (1999).