現有的三種白光LED作法分別為1.利用AlGaN LED發出UV光來激發三種螢光物質，分別發出紅、綠及藍光三原色來混成白光。2.另外常見的是由日亞化學所提出的方式，用InGaN LED發出的藍光去激發YAG:Ce3+螢光粉發出黃光和未被吸收的藍光混成白光，以上兩種方法皆須作波長轉換，在現今講究效率的時代，並非最佳的方式。3.由R、G、B三原色LED混成白光，但是由於其系統複雜度及成本上都過高而屈居於劣勢，此外還有一個最大的問題是在InGaN的材料上，目前還不能做出高效率的紅光LED，但是這種三原色的混光方式在效率上有很大的優勢，而且可自由地調整所需的顏色，在照明及顯示器上的應用會有很大的潛力。由於現有三原色LED在技術上有瓶頸存在，所以我們提出一種混成白光的方法，結合現在成熟的InGaN藍光LED和現今已逐漸成熟的OLED，由其來提供黃光。
　　
　　此方法其特點在於：(1)有機無機兩部分皆製作在同一基板所以系統複雜度低。(2)兩者發光皆不需做波長轉換，因此效率方面，相較於其他白光元件佔有優勢。(3)同時可分別控制兩者的電流，即可自由的調整所需的顏色，故有不錯的應用性。
　　
　　在本研究中，由於在製作無機元件時，遇到了一些技術上的問題，故此論文著重在OLED方面的研究，其中包括有機元件的設計、mask的設計、有機元件的degradation、以及OLED的spectra在低溫下的變化。
　　
　　在實驗結果中，我們做出以下結論1.CCD感應器的dark count對CIE座標的影響在於計算過程中對積分式產生誤差。2. 有機材料所形成的dark spot的過程推測應該是先有pinhole的產生造成最初的dark spot之後的成長過程由結晶化和delamination這兩類機制主導。3.我們找到有機發光元件在低溫低壓時其 EL spectrum出現的兩個peak的精確位置，可幫助我們瞭解此元件之發光材料的物理特性。4.本論文所提出的構想在混色實驗中成功地驗證，雖然實驗結果並未混出很好的白光，那是因為我們實驗中選擇的藍光LED的顏色不適合，因此根據結果我們之後在製作無機元件部分時可考慮發光波長為485nm，如此搭配有機發光元件就可混出較佳的白光品質。

　There are three different approaches to generate white light illuminations. The first approach is by using ultraviolet (UV) radiation from UV light emitting diodes (LED) to excite phosphors, white light can be generated by mixing the red, green and blue lights from excited phosphors. The second approach, which is patented by Nichia Chemical, is by using blue InGaN-based LED to excite YAG:Ce3+-based phosphor, the yellow light emitting from the phosphor and the residual blue light produce the white light. The efficiency for these two approaches are limited due to wavelength conversion of the injected photon. Combining emission from red, green and blue LEDs to produce white light is the third approach. The high system complexity and high cost are the major obstacles for this approach. In addition, there are no high efficient red InGaN-based LEDs available now. However, this approach has several advantages, including higher efficiency due to no wavelength conversion and color flexibility. There are huge potentials for applications of illumination and display.
　
　A novel concept is provided in this dissertation based on the color mixing approach. By combining blue InGaN-based inorganic LED and yellow organic LED, white light can be generated with advantages, including low system complexity (one chip), no wavelength conversion, and flexibility (emit light of desired color).
　
　In this dissertation, we focus our study on the organic device since technologic problems in fabrication of the inorganic devices. Results from the design of organic devices, the design of mask were studied. The degradation of organic device and variation in spectra of organic in low temperature were also studied.
　
　From the experimental results: 1. dark counts of the CCD sensors can influence the calculation of chromaticity coordinates. 2. the initial dark spot formation for organic devices is due to the pinhole formation and crystallization and delamination will also lead to growth of more dark spots. 3. The positions of the two EL peaks for organic light emitting device can be identified. This will help us understanding the basic physics of the organic material studied. 4. We successfully demonstrate the concept to generate white light. The bad quality of white light can be improved by choosing an inorganic LED emitting 485nm light. This will lead to better white light generation.

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