新型電極結構於垂直配向邊緣場效驅動液晶顯示器模擬研究

Abstract

在顯示器普及的當代，兼具高亮度與快反應速度的液晶顯示器，依舊是顯示器發展的重要指標。在諸多顯示驅動架構中，邊緣場驅動（FFS）技術因具備廣視角與高亮度等本質上的優勢，已被廣泛應用於各類主流顯示裝置。然而，如何在既有優勢下進一步優化其反應速度與穿透率，仍是當前提升顯示性能的重要課題。 而在本實驗室中，過去所使用的正型液晶E7-01由於反應速度較慢的問題，因此在本論文中選擇更換其黏度較低的另一液晶材料PLC，但是在更換後之材料有著穿透率較低的問題存在，也因此本研究主要著重於提升該液晶的穿透率，從最原始之結構出發，逐步延伸並改良其電極結構，使最終結構能讓原始結構穿透率增加25%。本論文首先提出單邊雙層電極結構，將下層電極更換為圖案化電極，以增加底層液晶分子的轉動角度，由於穿透率提升有限，因此再提出雙邊三層電極結構，利用加入上方電極來創造一新電場，使結構內部能夠有更多的液晶受到偏轉，但穿透率仍然有限，且拉長反應速度，最終提出之雙邊四層電極結構不但能夠有效增加其穿透率，同時可以有效改善前結構反應速度過慢的問題，且同時克服在正型液晶在前人研究之結構下穿透率較低的問題。 本論文最後改良了本實驗室先前研究中提出之反轉結構，無法在小尺寸下穩定運作的問題，將原本為六邊形排列之電極，改變為四邊形之排列，此舉能夠穩定結構內部電場，加固電場邊界，並且有效固定虛擬牆位置，使其不再產生過度移位的問題，在大幅提升結構運作穩定性的同時，依然能維持原有的高穿透率水準。

This study presents a structural optimization approach for Fringe Field Switching (FFS) liquid crystal displays (LCDs) to resolve the trade-off between transmittance and response speed. To address the slow response time inherent in the conventional positive liquid crystal material E7-01, a lower-viscosity positive liquid crystal material, PLC, was introduced. However, PLC exhibits lower optical transmittance. Starting from the Original Square Structure, this work systematically redesigns and extends the electrode configurations, ultimately achieving a 25% transmittance increase over the original design while substantially enhancing dynamic performance. Initially, a Single Side 2 Layers Structure featuring a patterned bottom electrode was developed to enlarge the twist angles of the bottom-layer liquid crystal molecules; however, the transmittance improvement remained constrained. Subsequently, a Double Side 3 Layers Structure was proposed, incorporating a top electrode to generate an additional electric field and induce further molecular deflection. Although this extended the field interaction, transmittance gains were still limited and the response time was prolonged. To overcome these limitations, a Double Side 4 Layers Structure was designed. This configuration effectively boosted transmittance, resolved the slow response issue associated with the 3-layer layout, and successfully addressed the low-transmittance limitation observed in previous positive liquid crystal studies. Finally, this study improves upon the operation instability in small-dimension regimes observed in the inverted structure proposed by our laboratory's previous research. By reconfiguring the electrode arrangement from a hexagonal tiling to a quadrilateral layout, the internal electric field is stabilized, field boundaries are reinforced, and the virtual wall positions are effectively anchored to eliminate excessive displacement. Consequently, this structural modification drastically enhances operational stability while preserving the high transmittance characteristic of the original design.