配向層修飾對Pi-Cell光電特性之研究

Abstract

近10年來，平面顯示器的蓬勃發展，帶動顯示器的革命，成功取代傳統CRT。在這波平面顯示器熱潮中，由於液晶顯示器具有輕、薄、省能的特性，並且各種尺寸都有其應用產品。因此，成為眾多平面顯示器中的最重要的技術。然而，在大尺寸的應用中，動態影像品質主要受限於液晶的反應時間太長，液晶反應速度成為動態影像優劣的關鍵，動態影像一直無法和傳統CRT比較。所以具快速應答的液晶操作模式是近年來被熱烈討論及研究的對象。在各種模式之中，最備受矚目的就是光學補償彎曲(optically compensated bend ,OCB或稱Pi-cell)。 Pi-cell的操作主要是介於Bend狀態與垂直的狀態之間，而且這兩種狀態液晶的差異並不大，並且電壓移除後不會有反向流動現象，反應時間會比其他模式快。但Pi-cell在操作之前，分子排列成Splay狀，操作前通承需要提供偏壓並且持續一段時間，才能正常驅動。本篇論文特別使用能夠聚合的液晶材料，可以降低偏壓，並且改良Pi-cell的暗態，進而提升對比度，並且不影響到其反應時間。此外，也將討論此聚合型液晶材料的表面及特性。

In the last one decade, flat panel displays have developed vigorously, promote the display revolution, and replace CRT successfully. In this current of flat panel displays, LCDs have the properties of light, thin, power saving, and have products of each size, so LCDs become the most important technology of numerous flat panel displays. However, in the application of large size, the long response time of LC has limited the moving image quality, the response time of LC becomes the key issue of moving image quality, can not compare with conventional CRT. So the operation mode of fast response LC have been discussed and studied hot. In numerous modes, the optically compensated bend (OCB or Pi-cell) mode. The operation of Pi-cell mode is mainly between the bend state and the homeotropic state, and the difference of LC alignment between these two states is not much, and doesn’t have the back flow effect after the voltage removed, has the faster response than other mode. But before Pi-cell operates, the LC molecules align in splay, and we usually need to apply a bias voltage for a period of time to operate. This thesis especially uses the liquid crystal material which can polymerize, can reduce the bias voltage, and improve the dark state of Pi-cell, then increase the contrast ratio, and doesn’t affect the response time. Besides, we will discuss the surface morphology and some properties of this polymerized liquid crystal material.