應用於會聚、發散與3D顯示之多電極液晶透鏡之設計與製造

Abstract

本論文主旨為研究與探討液晶元件(Liquid crystal devices)之應用，其主要目的為設計多電極液晶透鏡，並應用於會聚與發散透鏡與立體顯示(3D Display)系統。於會聚與發散透鏡之應用，其有別於傳統液晶透鏡其孔徑被液晶層厚度有所限制，以及其液晶分子難以精確控制。本論文提出多圈不等寬電極之設計，並因應此設計發展出多層電極結構之製程，以避免多圈電極走線干擾，此電極設計實現於大孔徑4mm會聚與5mm發散液晶透鏡，並能夠較準確地控制液晶分子為期望之折射率分佈。此外，為提升液晶透鏡之反應時間，本論文提出一雙頻液晶透鏡之設計，其採用雙頻液晶(Dual-frequency liquid crystal, DFLC)材料，並搭配環與派(Ring-and-pie)電極圖案結構以及一合適的驅動方法，達到改善液晶透鏡之回復時間(Recovery time)，除此之外，並探討液晶透鏡之液晶分子排列向錯現象(Disclination line effect)，且改善之。本論文中，液晶透鏡應用於非成像光學，主要討論裸眼立體顯示(Auto-stereoscopic display)技術，其目的欲將液晶透鏡取代傳統圓柱透鏡(Lenticular lens)，並應用於裸視立體顯示系統。本研究提出液晶圓柱透鏡陣列之設計準則，並針對裸視立體顯示系統與傳統圓柱透鏡陣列建立光學模型，分析與量化系統之表現，其包含觀測者於不同位置與不同視角之串擾效應(Crosstalk effect)，並在此光學模型中，建立液晶圓柱透鏡陣列模型。本論文提出交錯式(Interlaced)電極結構與多電極(Multi-electrode)結構之設計，分別製作出2.8吋以及4.4吋之液晶圓柱透鏡陣列，並量測其透鏡陣列之表現。

This dissertation is dedicated to study and discuss applications of liquid crystal (LC) lenses with designed multiple electrodes, which consists of two main parts -- imaging optics system and 3D display system. For the application to imaging optics system, novel convergent/divergent LC lens devices with large aperture and multiple ring electrodes in unequal widths are proposed by this work, in order to offer tenability on focusing quality and to render a better refraction index distribution for focusing, as compared to the past hole-type LC lenses. A new fabrication process in the wafer level to bury bus lines is developed for generation smooth electrical fields over the lens aperture. In addition, a new LC lens using dual-frequency liquid crystals (DFLC) is proposed to improve the recovery time with a ring-and-pie electrode pattern through a suitable driving scheme. For this device, one can control the orientation of liquid crystal directors via a three-stage switching procedure on the particularly-designed ring-and-pie electrode pattern. This aims to eliminate the disclination lines, and using different drive frequencies to reduce the recovery time. For the application to 3D display system, a liquid crystal lenticular lens (LCL-lens) array device which is proposed to compose an auto-stereoscopic display, in order to replace conventional lenticular lens sheet. This study proposes design criteria of LCL-lens array for auto-stereoscopic display system. An optical model is built with LCL-lens array to analyse and qualify its crosstalk and performance, while an observer observes the system in different observer distances and angles. In addition, two LCL-lens array devices are designed with interlaced and multi- electrode pattern to realize 2.8 and 4.4 inch fabrications respectively, and then be measured to result their performances in this dissertation.