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標題: | 運用外部和內部微透鏡陣列促進有機發光元件出光效率之研究 Coupling Efficiency Improvement of Organic Light-Emitting Devices Using External and Internal Microlens Arrays |
作者: | Hai-Song He 何海松 |
指導教授: | 林晃巖 |
關鍵字: | 有機發光二極體,微透鏡陣列,波導模態,基板模態,全反射, organic light-emitting diode,micro-lens array,waveguide mode,substrate mode,total internal reflection, |
出版年 : | 2017 |
學位: | 碩士 |
摘要: | 有機發光二極體(organic light-emitting diode,簡稱OLED)由於其自發光、廣色域、反應時間快、可製作大尺寸、可撓性、構造簡單、高演色性等特性,所以被視為未來重要的顯示技術與照明裝置。
OLED由於其層狀堆疊結構,因不同材料間折射率的差異,造成大部份光線在結構內產生全反射 (total internal reflection) 而無法從結構中被耦合到空氣中,使整體的出光效率降低,所以出光效率的提升為目前有機發光二極體一重要的研究課題。為了增加OLED的出光效率,在玻璃基板上貼附外部微透鏡陣列是目前常使用的技術之一,是以破壞玻璃基板與空氣介面之間的全反射,提高光耦合的效率。 本篇論文首先分析了橢球狀的微透鏡對於出光效率的影響。在OLED上加入外部微透鏡陣列能夠有效的減少玻璃基板與空氣之間的全反射,增加光的萃取,使OLED的出光效率增加,但OLED內部透明電極層ITO的折射率高於玻璃基板的折射率,光線會在ITO/玻璃基板介面產生全反射,也會影響光萃取至空氣外部的效率,所以此論文中會在ITO和玻璃基板介面加入內部ITO凹凸狀的微透鏡,希望能夠有效地減少有機層與ITO陽極介面間全反射,將波導模態的光線萃取轉成基板模態,再進一步用外部微透鏡將光線萃取耦合到至空氣,進而大幅增進元件效率。此外,在玻璃基板上貼附了半球大透鏡(macro-lens),把基板模態的光最大極限的光萃取出來。 The organic light-emitting diode (OLED) can be used for large-size, flexible, simple structure, high color rendering index(CRI), spontaneous light and surface source, wide color gamut and fast response time. So it can be regarded as an important in both solid state lighting and display technology in the near future. The organic light-emitting diode is a layer-stacked structure and the emitted light is trapped in the stacked-layer of OLED. The total internal reflection (TIR) can take place between the different layers of OLED due to refractive index mismatch. And this results in low out-coupling efficiency. Therefore, the improvement of light out-coupling efficiency is an important topic for the organic light-emitting diodes. It is a common method to improve the out-coupling efficiency through destroying the optical total internal reflection at glass/air interface by attaching microlens array (MAs). In this thesis, we first compared and investigated the effect of the short-elliptical, hemispherical and long-elliptical MAs on the coupling efficiency. The external microlens array is attached on the glass substrate to destroy the total internal reflection between the glass substrate and air interface. The out-coupling efficiency can be greatly improved by attaching MAFs. But the total internal reflection can also cause at indium tin oxide (ITO)/glass interface is called the waveguide mode. So we want to destroy the TIR between substrate and ITO, internal concave and convex MAs are added on the glass/ITO interface to improve the coupling efficiency of organic light-emitting devices (OLEDs). The light extraction of waveguide mode is extracted into the substrate mode, and then the light extraction is coupled to the air by external MAs, which can greatly improve the efficiency of the OLED. In addition, a hemispherical macro-lens is attached to the glass substrate, and the maximum limit of the light of the substrate mode is extracted. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/77859 |
DOI: | 10.6342/NTU201704074 |
全文授權: | 有償授權 |
顯示於系所單位: | 光電工程學研究所 |
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