三維水平配向邊緣場效驅動液晶顯示器在雙層電極結構之模擬研究

Abstract

本論文延續蔡永傑博士及研究團隊在水平邊緣場效驅動液晶顯示器的研究，透過TechWiz模擬軟體，探討正型及負型液晶材料在三維水平配向邊緣場效驅動顯示器3D PA-FFS中，三維結構間的分子轉動、穿透率與響應時間特性。 本論文沿用邱園竣學長的正型液晶三維樹狀型枝幹電極結構設計，簡化液晶分子複雜的光學配向過程。當施加電壓在此結構時，液晶分子因枝幹電極與共用電極間的電場作用而旋轉，主幹電極在此過程中替代了配向層的功能，使液晶分子有規律地轉動，形成虛擬牆與發光區域。並且探討了不同主幹電極寬度、枝幹電極寬度與間距的匹配，發現不同的三維結構對顯示器的穿透率和響應時間有顯著影響。本論文在結構設計上也從陳世睿學長的論文中獲得啟發，透過設計完成的三維電極結構，將原本堆疊在下層玻璃基板的電極以同樣的方式堆疊於上層玻璃基板下方，形成上下完全對稱的雙層電極結構。經過堆疊後的雙層電極，不僅顯著提升顯示器的穿透率、縮短響應時間，操作電壓也有明顯的改善。 在這篇論文中同樣重要的發現，從游仕毅學長的研究基礎上，將模擬的範圍逐漸縮小至顯示器的最小單位面積，發現比先前模擬更清晰的發光情形與虛擬牆分佈，並得到更連續的光電曲線及更快速的響應時間。 最重要的是，本論文將先前蔡永傑教授發表的VA-DFFS技術，運用在水平配向的雙層電極結構中。此結構採用畫素電極錯位排列的設計，經過改變畫素電極寬度和液晶層厚度後，不僅改善了虛擬牆造成的暗態區域，更大幅地提升了顯示器的穿透率。 本論文透過整合和改進先前的研究，從研究數據中發現經由改善電極結構的設計，可以顯著提升顯示器的穿透率和響應速度，並改善操作電壓。希望這些發現能為液晶顯示技術的發展提供新的思路與參考。

This thesis extends the research of Dr. Wing-Kit Choi and his team on parallel-aligned fringe field switching liquid crystal displays (PA-FFS). Using TechWiz simulation software, it explores the characteristics of molecular rotation, transmittance, and response time in positive and negative liquid crystal materials within 3D structures of PA-FFS displays. The thesis adopts the 3D electrode structure design for positive LC by Senior Chiu Yuan-Chun, simplifying the complex optical alignment process of LC molecules. When voltage is applied to this structure, the liquid crystal molecules rotate due to the electric field between the branch electrodes and the common electrode. The main electrode (or Trunk electrode) functions like an alignment layer during this process, allowing the liquid crystal molecules to rotate in an orderly manner, forming virtual walls and transmission areas. The paper investigates the matching of different main electrode widths, branch electrode widths and spacing. We found that different 3D structures could significantly affect the display's transmittance and response time. The structural design of this thesis is also inspired by the thesis of Senior Chen Shi-Rui. By designing a 3D electrode structure, the electrodes originally stacked on the lower glass substrate are similarly stacked below the upper glass substrate, forming a completely symmetrical double-layer electrode structure. The double-layer electrode stacking significantly improves the display's transmittance and shortens the response time, with notable improvements in operating voltage. Another important finding in this thesis, based on the research of Senior You Shi-Yi, is that by gradually reducing the simulation scope to the smallest unit area of the display, a clearer transmission pattern and virtual wall distribution than previous simulations were observed, yielding more smooth electro-optic curves and faster response times. Most importantly, this thesis applies the VA-DFFS technology, previously published by Dr. Wing-Kit Choi, to a parallel-aligned dual-electrode structure. This structure uses an arrangement where the upper and lower electrodes are shifted by half the LC layer, it not only helps reduce the dark areas caused by virtual walls but can also significantly enhance the display's transmittance. This thesis integrates and improves upon previous research, discovering from the data that an improved electrode structure design can significantly enhance the display's transmittance and response speed, while also improving operating voltage and contrast ratio. It is hoped that these findings can help provide new insights and understandings for the development of fast-response liquid crystal display technology.