液晶透鏡陣列光場顯微鏡之 加速反應時間和影像品質分析

Abstract

光場顯微鏡擁有即時記錄空間中的光場資訊(x, y, u, v)的能力，因此被視為最有潛力成為下一代立體顯微鏡系統的候補。然而受到目前光學元件的限制，例如感光器解析度、微透鏡陣列的數值孔徑等，光場顯微鏡的工作範圍與影像解析度都還有很多改善的空間。因此我們提出利用液晶透鏡陣列元件具有體積小、重量輕、焦距可調變的特性，搭配適當的光學系統設計，達到提升光場顯微鏡工作範圍和增加影像解析度的能力。 在本論文中，我們試圖解決我們實驗室以前提出的高電阻層液晶微透鏡陣列（Hi-R LC-MLA）的兩個問題。一個是反應時間過慢，另一個是光場液晶顯微鏡的影像品質分析。從我們的實驗結果中，透過減少液晶層厚度和使用過電壓驅動方法(overdrive method)，我們將反應時間從約15 s減少到75-90 ms。並計算調製傳遞函數(MTF)與有效分辨率(ERR)之間的關係，找到最合適的深度重建範圍。 結合上述兩項研究，我們可以將平面深度重建範圍從50 um擴展到350 um，且反應時間只需75-90 ms。

The light field microscope has the capacity of recoding 4D information (x, y, u, v) with a single snapshot. It is considered as the next generation 3D microscopy system. However its working range and image resolution are limited by the present optical devises and materials, such as the lens power or sensor pixel size. Therefore, we developed liquid crystal lens array with advantages as tiny volume, slight weight, and tunable focal length, to achieve the functions such as resolution enhancement, extending depth of field, and fast scanning process. In this thesis, we try to solve two problems with high resistance layer liquid crystal micro-lens array (HiR LC-MLA) that our lab has previously proposed. One is the response time issue and the other is the image quality analysis on light field LC microscope. In our experiments result, by reduce the cell gap and overdrive method, we reduce the response time from about 15s to 75-90ms. And calculate the relationship between Modulation Transfer Function and Effective Resolution Ratio to find the most suitable work range. Combined with the above two studies, we can extend the working range from 50um to 350um, and the response time only need 75-90ms.