高分子穩定負型液晶元件的光電特性

Electro-Optical Properties of Polymer-Stabilized Liquid Crystals with Negative Dielectric Anisotropy

許力仁(Li-Jen Hsu)

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/cycu200700635

摘要

近年來，利用高分子網絡提供液晶分子侷限效應及調整液晶盒整體的錨定力來改善其光、電表現一直是廣為研究的課題。在本論文中，我們研究不同的高分子穩定負型液晶之光聚合參數以達到控制樣品光電特性的目的。在本系統中，我們觀察到不同的高分子單體濃度及聚合電壓不僅改變液晶塊材內的高分子網絡的成長方向，更會改變高分子單體在液晶中的分佈進而形成不同的高分子層形貌，這些迵異的高分子結構會隨著聚合電壓的不同而對配向層錨定作用有加乘或消弱的效果；另外我們也發現液晶分子的迴流現象會隨著高分子濃度及聚合電壓的增加而受到抑制，經由DIMOS模擬軟體，我們成功地對等效彈性常數對迴流現象的影響作出定性的描述；最後我們對無摩擦定向的液晶盒作了一些光電特性及視角上的研究，結果顯示無聚合電壓的高分子網絡不會破壞寬廣的視角，但隨著聚合電壓加入，高分子網絡會消除液晶的錯向線和改善光電特性，但此聚合電壓會破壞視角的對稱性。

關鍵字

負型液晶 ； 高分子濃度 ； 高分子穩定型液晶 ； 聚合電壓

並列摘要

In recent years, the polymer and liquid crystal mixtures have been wildly studied. The three-dimensional anchoring force by the polymer network could proved stronger support and improve the electro-optical properties. In this thesis, we mixed a liquid-crystal material possessing negative dielectric anisotropy (岛讨 < 0) with RM-257 (岛讨 < 0) together and fabricated polymer-stabilized liquid crystal cells in the vertically-aligned mode with different monomer contents prepared at distinctive curing voltages. The formation of the network direction could be parallel or perpendicular to the substrates by various applied curing voltages. Therefore, the network could either enhance or weaken the anchoring force by different experimental processes.
It was found that one. can control the polymer morphology to suppress the backflow in the LC cell and a qualitative relationship between the backflow suppression and the effective elastic coefficients could be established with a DIMOS simulation software. Furthermore, we fabricated an amorphous polymer-stabilized liquid crystal cell without rubbing the alignment layers. The amorphous cell exhibited a wider viewing angle. Unfortunately, the curing voltage destroyed the viewing angle symmetry.

並列關鍵字

monomer concentration ； negative liquid crystal ； curring voltage ； PSLC

參考文獻

[5] 黃文賢，《添加碳奈米管之高分子聚合物穩定型液晶元件的光電特性》，碩士論文，中原大學應用物理研究所，民95年。.

[3] V. G. chigrinov, Liquid Crystal Display Physics and Applications (Artech House, London, 1999).

[4] N. A. Clark and K. M. Johnson, in Liquid Crystals: Applications and Uses, edited by B. Bahadur (World Scientific, Singapore, 1991), Vol. 3, chap. 17, pp. 209–252.

[6] K. Maruyama, T. Houryu and Y. Iimura, “Realization of vertical alignment with low pretilt angle by polymer-stabilized technique,” Journal of Photopolymer Science and Technology 19(2), 157–162 (2006).

[7] M. F. Shiekel and K. Fahrenschon, “Deformation of nematic liquid crystals with vertical orientation in electric fields,” Applied Physics Letters 19(10), 391–393 (1971).