應用實驗設計法探討PI膜液晶配向製程之研究

A Study on the Polyimide Film's Liquid Crystal Alignment Process Using the Design of Experiments

陳泰宏(Tai-Hong Chen)

指導教授 ： 鄧治東教授

中原大學/工學院/機械工程研究所/碩士(2006年)

https://doi.org/10.6840/cycu200600603

摘要

非接觸式配向因可解決刷磨式配向所帶來的污染問題而受到產學界之重視。本論文乃以新興技術電漿束液晶配向來製作LCD配向膜，研究中藉由實驗設計法之應用、PI膜材特性量測及液晶Cell光學量測三者的交叉比對討論來獲得電漿製程參數與液晶配向的關係。

有鑑於電漿束配向製程實屬複雜之程序且電漿製程參數種類繁多，因此本研究應用實驗設計法探討電漿製程參數對其配向膜材特性與液晶光電量測 (預傾角)之影響情形。由於配向膜材為PI膜，實屬有機化合物，因此對配向膜材作物理性轟擊及化學性反應的討論，從結果中發現進料氣氛為本研究選定討論製程參數影響目標函數最顯著的因子。

從物理性轟擊討論，當進料氣氛為純Ar時，經由膜厚量測儀、AFM量測、蝕刻速率及電流密度量測發現所擁有的離子轟擊力是比其他組實驗大；從化學性反應討論，經由ESCA量測及接觸角量測，當進料氣氛為純Ar時接觸角較大、氧碳比較小，所代表的訊息是疏水性較佳。總結，電漿束離子配向轟擊PI膜確實會造成順序性的溝槽，雖然工作電壓加大，會加速腔體內的反應；轟擊時間越長，累積能量越大，不過以上兩項製程參數對於溝槽的大小及薄膜表面親疏水性影響並不大，對於液晶預傾角影響也不顯著，當轟擊時間越長的話，並未得到較大的預傾角。所以控制液晶預傾角最直接的方法就是控制進料氣氛，再搭配適中的轟擊時間，即可有效的控管液晶預傾角。

關鍵詞：非接觸式配向、電漿束液晶配向、預傾角、實驗設計法

關鍵字

PI配向膜 ； 非接觸式配向

並列摘要

Abstract
Non-contacting alignment technology has attracted much attention of the academia and industry for the last decade due to pollutant problem related to the alignment method by brushing and rubbing. This study dealt with the liquid crystal display (LCD) alignment layer, developed by advanced plasma beam LC alignment technology. In this study, experimental design methodology, polyimide (PI) films characteristic, and LC cell measurement were used to investigate the relationships among the plasma processing parameters and the LC alignment.
As a result of the complexity involved in the processing of the plasma beam alignment and the diversity of the parameters associated with the plasma processing, this study used the methodology of experimental designs to evaluate the impact of these parameters on the characteristics of the PI films and the LC pretile angles for the opto-electronic measurements. Since the PI films for alignment were organic compounds, their physical bombardment and chemical properties were investigated. The results of this study indicated that the gas ratio of hydrogen to argon was the most prominent factor affecting the process parameters.
From the ion bombardment view point, as the gas environment to be pure argon, the force resulting from the ion bombardment was found to be larger than the other cases using the measurements of the film thickness, force by atomic force microscopy (AFM), itching rate, and current density. From the chemical reaction view point, the contact angle was larger and the ratio of oxygen to carbon was smaller for the case with pure argon, as measured by the Electron Spectroscopy for Chemical Analyzer (ESCA) and by the Contact Angle Analyzer. This revealed that this case is hydrophobia. In summary, PI films were aligned by plasma ion beam bombardment indeed resulted in sequential grooving of the films. Even though an increase in the applied voltage led to the reaction inside the chamber, the longer the bombardment time, the higher it was for the accumulated energy. Nevertheless, the impact of the process parameters on the width of the groove and on the wettability of the film surface was not large. Its impact on the LC pretilt angle was not obvious either. The pretilt angle did not seem to be larger by prolonging the bombardment time. Therefore, it was concluded that the most direct means for controlling the LC pretilt angle was to control the gas ratio of hydrogen to argon, together with adequate bombardment time.

Keywords: Non-contacting alignment, Plasma beam alignment, Pretilt angle,
Experimental designs

並列關鍵字

Non-contacting alignment technology ； PI alinment layer

參考文獻

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