鐵電型液晶相位光柵元件之研究

Abstract

近年顯示科技領域發展，液晶光學研究及各式液晶材料合成進步，更加廣泛應用在於顯示科技上，而不僅僅是在顯示方面，更應用於光電元件，在此研究我們提出一種元件結構是經由兩片週期線條ITO玻璃對位重疊製成空cell，因而形成ITO區塊與非ITO區塊週期交錯，並灌入液晶來製程可調控式液晶光柵，利用週期光柵電極產生之均勻電場調控液晶排列，因而形成所謂 Binary phase grating。

本研究使用鐵電型液晶材料(R3206-50)，此材料除了具有快速響應特性外，也具有較低的飽和電壓，約5V。然而在實際用上，受限於排列不佳的問題。本實驗藉由調整配向膜的表面正負極性，來解決水平山形袖章結構之缺陷，形成單一方向排列之層結構。近幾年來利用鐵電型液晶光學特性來製作光柵的方法提出很多，比較其眾多方法及不同材料利用，此液晶光柵具有相當程度的優勢，兼具快速反應時間(1.3ms)、低驅動電壓(5V)、較低的fringing field effect、較高的繞射效率(25.8%)以及低散射效果。

A novel ferroelectric liquid crystal phase grating has been successfully prepared by periodically ITO (indium-tin-oxide) patterned stripes cell. Under external driving voltage, LC molecules were reoriented in ITO areas and cause phase difference between the areas without ITO. The binary phase gratings were formed within periodically alternating domains.

In this work, ferroelectric liquid crystal materials (R3206-50) were prepared. Low driving voltage FLC material, R3206-50 with Vsat. at 5V (AZ Electronic Materials), and its were under evaluation for liquid crystal optical devices application. The horizontal chevron alignment defects were suppressed by asymmetric hybrid alignment cell, and the fringing field effect was reduced with low driving voltage (5V). The response time of R3206-50 was under 1.3 ms in a 1.6 □m cell. Thus, a desirable fast switching, low driving voltage, low fringing field effect, low scattering effect and easy process FLC grating was presented.