無配向層鐵電性液晶盒配向機制探討

Method of Alignment of Ferroelectric Liquid Crystal Cell without Alignment Layer

羅立(Li Lo)

指導教授 ： 吳俊傑 ； 陳殿榮

國立臺北科技大學/電資學院/光電工程系研究所/碩士(2011年)

摘要

本篇論文研究在無配向層鐡電型液晶盒的配向機制，探討在反向rubbing、同向rubbing 處理的液晶盒，在進行電場配向後逹成垂直配向的機制。我們使用具有N*-SmA-SmC*相轉移的鐡電性液晶，並利用鐡電性液晶本身具有的層狀結構特性，施加電場在SmA相逹成垂直排列穩態。並且為了要降低逹到垂直配向的臨界電壓，我們也成功的於N*相實施電場配向然後降溫至SmA相逹成垂直配向排列。我們也發現，使用低頻(100~500Hz)的交流方波會使得層狀結構產生擾動，讓逹成垂直配向的臨界電壓變大。為了在SmC*相逹成垂直配向，我們分別比較了二種情況：(1)從N*相施加電壓，降溫至SmA相再移除電壓，後再降溫至SmC*相。(2)從N*相施加電壓直接降溫至SmC*相。從實驗結果可知，當從N*相施加電壓直接降溫至SmC*相，因為有一個電場的力量存在使得液晶分子傾倒方向較為一致，所以配向均勻性較高。
最後為了能在未來應用到可撓式基板顯示器上，因為高分子的分佈有助於在彎曲顯示時仍維持均勻的cell gap，所以我們將摻雜高分子來穩定FLC。我們將會討論高分子濃度對配向均勻性的影響以及討論改變curing的溫度對逹成垂直配向液晶盒的影響。

關鍵字

無配向液晶盒 ； 鐡電型液晶 ； 垂直配向 ； 高分子穩定

並列摘要

We present an electric field treatment method in ferroelectric liquid crystal cell without alignment layer that enable the uniform molecular orientation to be obtained in the planar aligned ferroelectric liquid crystal (FLC) cell. In this method, we used the FLC materials showing N*-SmA-SmC* phase sequence, the molecular orientation is changed from planar to homeotropic state in the SmA phase by the application of electric field due to the dielectric coupling. After the treatment of electric field, the smectic layers are initially formed parallel to the substrate plane in the SmA phase, leading to the stable homeotropic state.
To reduce the voltage that reached homeotropic state, we also have successfully use this method in N* phase. And the effect of electric field conditions such as the frequency, amplitude, and the duration of the electric field applied to the cell on the uniformity of alignment of the cell is clarified. In addition, the cell treated with electric field applied through N*-SmA or N*-SmA-SmC* phase transition shows more uniform alignment than that cell treated with electric field in the SmA phase.
At last, in order to apply the technique to flexible display, we used Polymer to stabilized the ferroelectric liquid crystal cell. We also discussed the impact of Polymer concentration on uniform molecule orientation and the impact of changing the temperature of curing Polymer on homeotropic state.

並列關鍵字

without alignment layer cell ； ferroelectric liquid crystal ； hometropic state ； electric field treatment

參考文獻

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