紫外光照射光配向膜之方法及性質研究

Abstract

摘要 一般的聚合物在照光之前必須經過軟烤(60 ~ 80℃, 5mins)和硬烤(200 ~ 250℃, 60min)的步驟，本實驗使用的聚合物是利用紫外光的照射來取代傳統的硬烤步驟，如此，可避免因硬烤的溫度過高破壞原有聚合物的特性，也可以大大的縮短整個樣品製作的時間。我們找出了使液晶分子配向的照光條件及步驟，將經照光處理過的玻璃基板做成液晶樣品，然後利用偏光顯微鏡觀察其明暗變化並測量其穿透率及預傾角，我們發現(1)磨刷定向法可以得到較均勻的配向，且利用磨刷定向做成的液晶樣品其對比較用光配向所做成的液晶樣品佳。(2)一片磨刷一片照光的液晶樣品，其預傾角為兩片都是磨刷跟兩片都是照光的液晶樣品的預傾角的平均。

ABSTRACT Photoalignment, a non-contact liquid crystal (LC) alignment method, is achieved by using films of photosensitive polymers irradiated with linearly UV light. This technique avoids many drawbacks of the traditional rubbing technique for LC alignment, such as sample contamination and static charge generation. In addition, it allows patterned alignment. The photoalignment material used is low-molecular-weight photo-crosslinkable (LMWPC) composites. We have found a effective preparing procedure. We have also built a pretilt angle measurement system using LabVIEW and GPIB interface. The cell rotating, data acquisition and analysis are all controlled by our program. The pretilt angle and transmission of the LC cells made with this alignment method are measured.