微透鏡應用於微型發光二極體之研究

Abstract

在顯示器產業中，微型發光二極體為潛在發展技術其中之一。相較於LCD及OLED， LED結合兩者的優點。既有自發光、高亮度、反應時間短、使用壽命長等優點，同時做到高發光效率。隨著科技進步，LED逐漸微型化，要維持一定良率後大規模量產，再轉移到基板上是一項艱難的挑戰。且尺寸縮減後，出現了側壁缺陷效應(sidewall defects effect)，導致LED發光效率低落，因此micro-LED至今仍未廣泛應用於顯示產業。 本篇論文目的是為了降低發光二極體的環境光反射，同時增加外部發光效率。微透鏡採取回流法製作，以達到光線匯聚的效果。設計初步先對模型分析光線強度分佈，將結果與實驗相互驗證後，建構模型上方之二次光學微透鏡。完成透鏡建構後，使用光學軟體LightTools®對整個模型做光線追跡，模擬結果發現確實達到環境光反射降低且能量損耗大幅減少。 最後將二次光學透鏡參數進行調整，針對架構上方30微米處半徑125微米之圓模擬可達到環境反射率最低4%，損耗降低至15%。

In the display industry, micro-LED is one of the potential development technology. Compared with LCD and OLED, LED combines the advantages of both. It has the advantages of self-luminescence, high brightness, short response time and long lifetime, and at the same time achieves high luminous efficiency. With the advancement of technology, LEDs are gradually miniaturized. It is a difficult challenge to maintain a certain yield rate as well as mass-produce them then transferring to the substrate. After the size reduction, sidewall defects effect occurs, resulting in low luminous efficiency of LEDs. Therefore, micro-LEDs have not yet been widely used in the display industry. The purpose of this paper is to reduce the ambient light reflection of LEDs while increasing the external luminous efficiency. The microlens design adopts the method of reflow to process. In the preliminary design, the light intensity distribution of the model is analyzed first, and after the results are verified with the experiment, the secondary optical micro-lens above the model is constructed. After completing the lens construction, use the optical software LightTools® to do ray tracing on the entire model. The simulation results show that the ambient light reflection is reduced and the energy loss is greatly reduced. Finally, the parameters of the secondary optical lens are adjusted, and the simulation of a circle with a radius of 125 microns at 30 microns above the structure can achieve a minimum environmental reflectivity of 5%, and the loss is reduced to 15%.