影響Pi-cell 鬆弛彎曲態存在之研究

Effect on the existence of Pi-cell Relax Bend state

李瑀玟(Lee Yu-Wen)

指導教授 ： 徐芝珊

中原大學/理學院/應用物理研究所/碩士(2010年)

https://doi.org/10.6840/CYCU.2010.00570

摘要

Pi-cell是近年來蓬勃發展的一種顯示器模組，其液晶盒之玻璃基板為同方向配向，與常見之均勻排列（Homogeneous）型液晶模組配向方向不同。由於上下基板配向方向相同的關係，使得液晶盒內部之液晶指向矢為上下對稱的分佈，此種對稱的結構使得Pi-cell具有快速反應以及視角對稱的優點。但也由於這種特殊的結構，使其操作時需要較長的暖機時間，並且需要持續供給一大於critical voltage的電壓，以確保其工作時可以穩定於彎曲態（Bend state）工作。我們已知當Pi-cell於垂直態（Stress Bend state）關閉電壓時，會短暫的穩定於鬆弛彎曲態（Relax Bend state），若可以利用鬆弛彎曲態與垂直態間做灰階的切換，則因不需保持電壓，可降低其耗電量。
在本論文中，主要是探討改變Pi-cell之液晶層厚度以及預傾角時，鬆弛彎曲態存在時間所受到的影響。實驗上，我們藉由混合PI的方式，製作不同預傾角之Pi-cell，並且利用不同的間隙物（spacer）製作出各種液晶盒厚度，量測這些參數對於鬆弛彎曲態存在時間的影響。並利用插黑技術，使Pi-cell操作時可以穩定於彎曲態，量測其不同電壓下之最低工作比（duty ratio）。我們並利用模擬程式分析Pi-cell之液晶指向矢於動態操作下的行為，以及各種製程參數與液晶參數對於鬆弛彎曲態存在時間的影響。

關鍵字

動態 ； 液晶 ； 鬆弛彎曲態

並列摘要

Pi-cell LCDs have been obtained considerable attention due to their fast response time and wide view angle. However, it requires a warming time to transfer LC molecules to the working state, which is the Bend state, and the operation voltage has to be larger than the critical voltage. The latter problem can be solved by using the Dynamic Relax Bend mode operation method, which the gray levels of pi cell are obtained between Relax Bend state and Stress Bend state. Since it does not need the holding voltage, the power consumption is reduced.

In this report, we have studied the influence of the cell gap and pretilt angle on the duration of the Relax Bend state. When the cell gap is increased, the duration of Relax Bend state becomes longer. However, the response time is also raised. When we increase the pretilt angles of pi cells by mixing homogeneous and vertical alignment polyimide, the duration of Relax Bend state is increased and the response is faster, but the phase retardation is decreased. We also use simulator to analyze the existence of Relax Bend state and the influence of cell and liquid crystal parameters on the duration of the Relax Bend state.

並列關鍵字

dymatic ； Relax Bend ； Pi-cell

參考文獻

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