- 學位論文
OCB Cell在格子狀結構光電特性研究
Electro-Optical Characteristics of OCB Cell with Patterned Alignment Region
摘要
隨著液晶顯示器的技術上的快速發展，對於液晶響應速度提升也相對越益重視，其中以光學補償彎曲模式（Optically Compensated Bend Mode；簡稱OCB Mode）液晶顯示元件最廣為大家研究，因為其特點在於: 響應時間快、廣視角。可是這種模式卻存在擴散模式(splay)轉換到彎曲模式(bend)的暖機時間問題，針對此點本研究主要利用光聚合高分子加入OCB cell內，配合光罩(Mask)並給予外加適當的電壓在UV下進行曝光，然後在偏光顯微鏡下外加電壓觀察液晶盒的平面顯示變化現象，此時未被光罩遮蔽部分的高分子將會聚合，藉由讓液晶順著光罩形成高傾角排列的格子狀結構與內部液晶產生不連續的缺陷結構，可用來加快液晶的轉態改善OCB的暖機時間。 實驗結果顯示：(1)利用格子結構確實可降低內部液晶轉態時間。 (2)取用適當的條件也可將液晶排列初始即穩定在彎曲模式或扭轉模式，因而無暖機時間的問題。(3)在扭轉模式可獲得良好穿透率與響應時間。
並列摘要
Optically compensated bend mode (OCB mode) displays attract considerable interest for having fast response time and wide viewing angle. To achieve a fast electrooptic response, the OCB-cell should be operated in the bend state. In practical applications, this device requires a high applied voltage to transform rapidly from the splay to the bend configuration. This transition takes a long warm-up time to stabilize the cell in the bend state. In this study, we try to solve this problem. Firstly, a mixture of nematic liquid crystal and photopolymer is employed in preparing OCB LC cells. The curing voltage (Vuv) and a mask are used on this cell in order to product aligned pattern regions. This region is able to nucleate the bend state and decrease warm-up time. Experiment results indicate: (1) Aligned pattern regions are able to decrease transition time. (2) At appropriate experimental conditions, the liquid crystal alignment can be stabilized in a bend mode or a twist mode so as to eliminate warm-up time. (3) The twist mode can achieve high transmittance and fast response time.