利用高分子製作HAN液晶顯示器之光電特性研究

Electro-optical Characteristics of Polymer Induced HAN Liquid Crystal Cell

高冠勤(Kuan-Chin Kao)

指導教授 ： 陳殿榮 ； 吳俊傑

國立臺北科技大學/電資學院/光電工程系研究所/碩士(2010年)

摘要

混合排列的向列型液晶(HAN-LC)元件由於低操作電壓、快速的響應時間和容易製造等等特點，因此可做為顯示應用。在傳統的HAN元件中，水平及垂直配向分別塗佈在頂部及底部的基板，而使得液晶分子造成兩基板間的排列為連續變化之混合(hybrid)分子排列，在這項研究中，我們提出利用高分子穩定HAN結構，只有一個基板使用水平配向液塗佈，而另一個為ITO基板。在經過照光過程後，使得高分子聚合在ITO基板上形成液晶垂直排列，而水平基板則可增加液晶分子的傾角，以達到光電特性最佳化。
利用液晶和單體混合物在不同濃度下對高分子穩定HAN透過偏光顯微鏡觀察以及進行光電量測、響應時間、相位變化、視角，以及基板表面的接觸角量測，配合模擬軟體DIMOS驗證實驗結果。此外，探討傳統HAN及高分子穩定HAN殘存離子電荷的影響。

關鍵字

HAN ； 高分子 ； DC offset voltage ； 接觸角

並列摘要

A hybrid aligned nematic liquid crystal (HAN-LC) cell is a potential candidate for display applications because of its features of low operation voltage, fast response time and easy fabrication process. In the conventional HAN-LC cell, the planar and homeotropic alignment films are respectively coated on the top and bottom substrates that the directors of LC molecules linearly vary from perpendicular to one of the two substrates to parallel to the other.
In this study, a polymer stabilized (PS) HAN-LC cell is created by doping photocurable monomer in the cell. In our proposed PS-HAN-LC cell, only one substrate is coated with planar alignment film and the other is ITO surface. After the photocuring process, the formation of polymers has the effect on creating homeotropic molecular alignment on the ITO surface and increasing the pretilted angle of the LC molecules on the substrate with planar alignment film.
The effect of LC/monomer mixture concentration on molecular configuration and electro-optical characteristics of the PS-HAN-LC cells are described by observing the microscopic textures and scanning electron microscopic textures, and measuring the voltage-dependence transmittance (T-V) curve, response time, phase retardation, viewing angle, and contact angle of substrate surface. The electro-optical characteristics of the HAN-LC cells are also simulated using commercial available software DIMOS to verify those of experimental results. In addition, the effect residual ionic charge which is one of the problems in the LC cell with alignment films on the electro-optical characteristics of the PS-HAN-LC cell is discussed and compared with those of the conventional HAN-LC cells.

並列關鍵字

HAN ； Polymer ； DC offset voltage

參考文獻

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