磁性奈米顆粒及電漿處理之聚醯亞胺薄膜表面之液晶配向及預傾角調變機制之研究

Abstract

利用電漿系統對鍍有聚醯亞胺薄膜的玻璃表面進行處理，取代傳統接觸式液晶摩刷配向，不僅能夠提升玻璃表面的潔淨度，也能夠避免靜電的產生，更重要的是能夠調變預傾角的大小。 本論文中的研究主要分成兩大方向，第一為電漿處理時間之效應、第二為能量之效應。由於電漿處理時可在玻璃表面沉積奈米大小之氧化鐵顆粒，電漿處理時間與外加能量能夠改變氧化鐵顆粒大小，影響樣品表面的粗糙度，甚至因氧化鐵的沉積速率不同而與聚希亞胺薄膜產生不同的化學鍵結，進而可調變預傾角的大小。 本文中將會針對不同參數的樣品量測預傾角，且對樣品表面進行分析，主要所使用到的方法有：原子力顯微鏡(AFM)、掃瞄式電子顯微鏡(SEM)、表面能分析及化學分析能譜儀(XPS)。經由觀察電漿處理過後的樣品表面所產生的變化，以進一步了解調變預傾角的機制。

The widely-used mechanical rubbing method in the liquid crystal display industries has some drawbacks such as leaving the dust, static charges, and scratches on the treated surfaces. Besides, it is also difficult to satisfy the demands for multi-domain pattern and high pretilt angle. To overcome these limitations, a non-contact surface treatment on the polyimide film by using a diode type plasma system has been studied. A capability of inducing high pretilt angle is found in this work. The influences of treating time and plasma energy on the alignment effect are discussed. A significant amount of maghemite nanoparticles are deposited on the polyimide surfaces treated by the plasma beam at the same time. To find out the mechanism of surface alignment with high pretilt angle, the relation between the surface roughness and the size of coated nanoparticles has been characterized by using scanning electron microscope (SEM) and atomic force microscope (AFM). Further investigations on the change of chemical bonds on the treated surfaces have also been carried out by using x-ray photoelectron spectroscopy (XPS).