| 摘要: | 藍相液晶最初被發現時僅存在於相當窄小的溫度範圍，而至今已有許多使藍相液晶存在溫度範圍拓寬的方法被提出，其中由日本H. Kikuchi教授團隊所提出的高分子聚合物穩固藍相液晶(Polymer-stabilized blue phase liquid crystals)為目前最常被利用於拓寬藍相液晶存在溫度範圍的方法。本實驗室於2016年提出相較於Kikuchi教授團隊不同的拓寬藍相液晶存在溫度範圍的方法，此為表面穩固藍相液晶(Surface-stabilized blue phase liquid crystals)，而本論文將探討於兩種不同聚合方式對於藍相液晶光電特性之影響。
在實驗過程中，將高分子聚合物穩固藍相液晶於不同照光時間之製程下，量測其藍相液晶施加不同電壓時的穿透度、雙折射、反應時間及晶格變化，且搭配表面聚合物穩固藍相液晶之穩固方法，以獲得與先前完全不同的光電特性，此外，因使用電極交錯排列的橫向電場基板會於光出射端造成繞射圖樣，為此比較兩者對於繞射效率及繞射圖樣之改變。最後，我們由兩種聚合物穩固後的新機制獲得不同的光電特性，但仍存在一些疑慮，若未來可朝此持續改善，相信對於藍相液晶未來之技術發展能有相當大的助益。
;One of the advantages of blue phase liquid crystals (BPLCs) is the property of fast response. However, the intrinsic temperature range of BPLCs is too narrow to be applied for real application. To expand the temperature range of BPLCs, several methods have been proposed. Among them, in 2002, Kikuchi et al. proposed a useful method to expand the temperature range of BPLCs based on polymer stabilization technique, which is the most commonly used method to widen the temperature range of BPLCs. In 2016, our lab proposed another method to broaden the temperature range of the BPLCs by surface stabilization technique. In this study, a comparison of electro-optical (EO) properties between the polymer stabilized (PS) BPLCs and the surface stabilized (SS) BPLCs will be made. Moreover, some characteristics of EO properties of SSBPLCs and PSBPLCs will also be demonstrated.
The study can be divided into three parts. First, we will discuss the change of effective refractive index difference of PSBPLCs under various applied voltages, whose direction is perpendicular to the substrate, by an inclined input light beam. Second, we will discuss the method to decrease the operation voltage of PSBPLCs. The operation voltage is high/low with/without adding photo-initiator in PSBPLCs. Third, the polarization dependent diffraction patterns and efficiencies of PSBPLCs and SSBPLCs will also be investigated. In the second and third parts of experiments, we will show that the optical hysteresis effect of SSBPLCs is smaller than that of PSBPLCs. Moreover, the response time of PSBPLCs/SSBPLCs in the second and third experiments will also be investigated.
We believe that the investigation in this study will be a useful reference to further studies of the SSBPLCs/PSBPLCs. Either the SSBPLCs or PSBPLCs have great potential to be applied for optical devices, such as LC display, grating, etc. |
