白光LED加速老化之光輻射特性之研究;Study of Emission Properties with Acceleration Aging of Phosphor-based White LEDs

Please use this identifier to cite or link to this item: http://ir.lib.ncu.edu.tw/handle/987654321/65190

Title:	白光LED加速老化之光輻射特性之研究;Study of Emission Properties with Acceleration Aging of Phosphor-based White LEDs
Authors:	鄭翰翔;Cheng,Han-Hsiang
Contributors:	光電科學與工程學系
Keywords:	白光發光二極體;YAG螢光粉輻射特性;加速老化;White LED;Emission Properties of YAG Phosphor;Acceleration aging
Date:	2014-07-29
Issue Date:	2014-10-15 14:42:56 (UTC+8)
Publisher:	國立中央大學
Abstract:	本論文分析了不同藍光波長的晶片搭配YAG螢光粉的LED樣品，在老化過程中輻射特性的變化。在LED的測試中，此研究採用高溫的方式來加速老化，以達在較短時間內觀察其壽命中不同時間點變化之目的。對於頻譜特性的分析，主要的成果分成兩個部分，第一部分，透過LED在其壽命過程中CCT、xy色座標以及u’v’色座標的變化資料，分析出使LED色彩變化穩定最佳的藍光晶片之搭配。此外，透過藍黃光分離並分析，亦可發現在混光機制上，藍光色座標的位移也能對結果造成明顯可觀察的結果，進而影響色彩穩定度的表現；在第二部分中，本研究分析LED頻譜的擬合參數，將其對應到螢光粉的能階狀態。此部分透過Stokes Shift以及4f能階分裂的計算，在比較過去其他研究後，可驗證並找出對應之關聯。其中利用不同溫度的數據變化，可以從高溫的測量資料中找出趨勢，延伸預測出低溫時的Stokes Shift，與文獻中7K的研究結果相仿。;In this thesis, we measured and analyzed several blue LEDs emitting different peak wavelengths with YAG phosphor, and observed the variations in emission properties under specific accelerating condition. In the aging tests of LEDs, severe high temperature condition was applied to accelerate the whole measurement duration. After analyzing spectra of different samples within the aging process, the best choice of blue light chip with YAG phosphor has been decided for stable color performance over the whole lifetime of LEDs. Besides, in the thesis, a fitting model was used to extract the information of energy level from the spectral properties. The results of energy level analysis have been compared with literatures, and show the sufficient correspondences in calculating Stokes shift and 4f splitting to demonstrate the accuracy of the model.
Appears in Collections:	[Graduate Institute of Optics and Photonics] Electronic Thesis & Dissertation

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