三維波浪型電極之低操作電壓和高光效率藍相液晶顯示器

Abstract

隨著人類科技的發展，日常生活中將會愈來愈多智慧型裝置是肯定的事情，而顯示器的需求更是隨之日益增加，液晶顯示器在近幾年來更是成為了不可或缺的產品，其中的藍相液晶更是被稱作未來最具發展潛力的顯示器材料之一，其具有亞毫秒的反應時間、暗態均向性等優勢，本論文主要為設計新的藍相液晶電極結構，解決藍相液晶顯示器過往大多存在著穿透率過低且操作電壓過高的問題。 本論文提出新的電極結構設計，自於西元2010年吳思聰教授團隊所開發的波浪型電極結構為發想，利用電極錯位的方式提供額外維度的水平電場，藉此來改善原先穿透率失效區的問題，進而提升最大穿透率，我們將此新設計結構簡單分為兩種並做了各種不同結構參數的配置，分別為三維波浪型電極結構 (I) 以及下方為整片畫素電極的三維波浪型電極結構 (II)，此新電極結構設計與傳統波浪型電極結構相比，可以保持在原先低操作電壓的優勢下，使大穿透率提升5%至8.4%，而操作電壓約落在11伏特左右，且有效降低了原先結構轉折處之穿透率失效區面積。本論文最後則為二維波浪型和三維波浪型的綜合比較，探討其優缺點，我們發現當電極寬度w為1μm時，三維波浪型電極結構 (I) 的電光表現是最優異的，而當電極寬度w為大於2μm時，三維波浪型電極結構 (I) 的表現下降而三維波浪型電極結構 (II) 維持不變，又在製程難易度上有優勢，因此三維波浪型電極結構 (II) 整體來說是較佳的。

With the progress of technology, it is no doubt that we will have more smart devices in our life. Furthermore, the increased demand of the liquid crystal display will also make it indispensable in the recent years. The blue-phase mode liquid crystal is known to have tremendous potential for future. Blue phase liquid crystal (BPLC) has several advantages, such as sub-millisecond response time and isotropic dark state. This operational mode for LCDs also does not require anisotropic alignment layers. In this thesis, we propose a new electrode structure for BPLC-LCD to improve the transmittance and lower the operation voltage of previous studies. In this thesis, we proposed a new electrode structure design. It is inspired by corrugated electrode structure, which was proposed by Prof S.T Wu’s group in 2010. Our new design is based on making electrodes mismatch, providing another horizontal electric field to improve the performance, and reduce the area of dead zone. There are two kinds of our new electrode designs. We try different parameters to find out its impact on the structure. There are 3D-Corrugated (I) and 3D-Corrugated (II) which has whole pixel electrodes in the bottom. These new designs can improve the transmittance up to 5% ~ 8.4% compare with traditional corrugated structure while still keeping in low operation voltage of about 11V. These new design reduce the dead zone area at the turning edge for the corrugated structure. At the end of this thesis, we compare the new design electrodes with the traditional corrugated electrodes, and discuss the advantages and disadvantages. We found when electrode width (w) is 1μm, the 3D-Corrugated (I) has best performance. When w is greater or equal to 2μm, the performance of 3D-Corrugated (I) got worse but 3D-Corrutaged (II) keeps having high transmission level. There is a great advantage of having easier fabrication process for 3D-Corrugated (II). Therefore, we believe the 3D-Corrugated (II) may be a better choice between our new design structures.