添加碳奈米管之配向劑於液晶顯示器之應用

Alignment Layers Doped with Carbon Nanotubes for LCD Applications

王彥超(Yen-Chao Wang)

指導教授 ： 李偉

中原大學/理學院/應用物理研究所/碩士(2007年)

https://doi.org/10.6840/cycu200700165

摘要

本論文之研究主要係針對配向劑中添加多壁碳奈米管於扭轉向列型液晶盒之相關電光特性及其應用。研究發現，添加碳奈米管於配向劑中若欲達成均勻混合之效果，則必須使用分散劑配製法；本實驗所使用之配向膜材料為聚醯亞胺高分子聚合物，利用此法可於聚醯亞胺成膜後達到良好的碳奈米管分散度。
由實驗量測結果結合液晶模擬（DIMOS Display Modeling System Version 2.0）所得之相關電光特性包含：一、隨著外加交流電場之頻率改變，添加碳奈米管於配向層中並不會造成樣品對頻率敏感度之變化；二、於配向層中添加碳奈米管之液晶盒，其樣品具有較高的閾值與驅動電壓；三、液晶盒整體之介電異方性由於配向層中碳奈米管的加入而微幅減少；四、在液晶盒中之配向層添加碳奈米管，可以有效降低樣品於外加交流電壓關閉時的液晶鬆弛時間，並大幅降低其回流效應；五、在添加碳奈米管之配向膜樣品中，液晶分子之預傾角增加；由實驗所得結果搭配凡得瓦力（Van der Waals force）中分子極性間作用力理論，可推測於配向膜中添加碳奈米管之物理機制模型。

關鍵字

配向膜 ； 碳奈米管 ； 液晶顯示器 ； 光電效應

並列摘要

The purpose of this thesis is to explore the electro-optical properties and potential applications of alignment layers doped with muti-wall carbon nanotubes (CNTs) in twisted-nematic (TN) liquid-crystal displays. According to our research, a dispersant must be introduced for homogeneous dispersion of CNTs in aligning agents. The alignment layer in this work is made of polyimide. Well-dipersed CNTs in the polyimide film can be obtained by means of the said intermixing method.
Several major properties acquired from the experimental results in conjunction with simulations (with DIMOS Display Modeling System Version 2.0) are as the following: 1. The sensitivity of transmittance to various frequencies of applied voltage remains unchanged in the sample with doped polyimide compared with the pristine one. 2. Samples with CNT-doped polyimide possess higher threshold and driving voltages. 3. The dielectric anisotropy of the liquid-crystal bulk sandwiched between CNT-doped alignment layers decreases slightly in comparison with that sandwiched between pristine alignment layers. 4. The relaxation time of the liquid-crystal cells decreases effectively and the amplitude of optical bounce drops dramatically when CNTs are introduced into the alignment layers as an additive. 5. Larger pretilt angle of liquid crystal molecules is observed in the TN samples with doped polyimide. The fundamental physical model for the system composed of CNT-doped polyimide can be foreseen with the interaction of molecules and polarities in the theory of the Van der Waals force.

並列關鍵字

electro-optical effects ； carbon nanotubes ； alignment layers ； liquid crystal displays