電極設計對三維水平邊緣場效液晶顯示器模擬研究

Abstract

本論文接續研究蔡永傑博士與邱園俊學長的三維水平邊緣場效液晶顯示器結構，探討在使用正型液晶下透過新增上層共用電極，透過改變上層共用電極的結構形狀與面積比例，探討對響應時間與穿透率的特性。 本論文提出新增的上層共用電極在施加電壓後，透過上層共用電極產生的Z軸方向電場，能夠幫助在分支畫素電極的區域產生虛擬牆，來協助穿透區域的液晶能夠有更快速的Fall Time。並且後續透過變更上層共用電極形狀類似於下層畫素電極，稱之為Symmetric Common，此形狀的上層共用電極能夠在施加相同電壓的情況下，獲得更多的斜向電場來拉動液晶，因此更進一步的縮短Rise Time。 為了在不會大幅影響響應時間的情況下，獲得更高的穿透率，因此本論文提出兩種方式，一種方法是透過變更上層共用電極的面積大小，來減少穿透區域液晶被上層共用電極的Z軸方向電場吸引走。另一種方式為不改變上層共用電極的面積大小，將液晶材料改使用負型液晶，透過此材料的高穿透率特性。上述兩種方式都能有效地提升穿透率，並且幫助我們對於上層共用電極結構的三維水平邊緣場效液晶顯示器有更加深入的認識。

In this thesis, we will continue to study the structure and design of PA-FFS liquid crystal display. It investigates the characteristics of response time and transmittance by introducing an additional upper common electrode in conjunction with the utilization of liquid crystal that has positive dielectric anisotropy. The effects of varying the structure shape and area ratio of the upper common electrode are explored. In this thesis, we proposed the addition of the upper common electrode that generates a Z-axis electric field, which aids in creating virtual walls in the region of branch pixel electrodes. This facilitates faster fall time for the light transmission area of the LCD. Furthermore, by modifying the shape of the upper common electrode to resemble the bottom pixel electrode, referred to as "Symmetric Common," a greater oblique electric field is obtained under the same applied voltage. Consequently, the response time is further reduced. In order to achieve higher transmittance without significantly affecting the response time, two approaches are proposed in this study. One approach involves adjusting the area of the upper common electrode to minimize the influence of the Z-axis electric field on the light transmission area of the LCD. The other approach involves maintaining the same area for the upper common electrode but using liquid crystal that has negative dielectric anisotropy, which exhibit higher transmittance characteristics. Both approaches effectively enhance the transmittance and provide a deeper understanding of the 3D PA-FFS LCD structure with an upper common electrode.