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標題: | 垂直配向邊緣場效驅動液晶顯示器之三維電極結構模擬設計 Simulation in Design of Three-Dimensional(3D)Electrode of LCDs using Vertically-Aligned Fringe-Field Switching |
作者: | Chia-Hsiang Tung 董佳祥 |
指導教授: | 蔡永傑(Wing-Kit Choi) |
關鍵字: | 快速響應時間,三維電極結構,三維垂直配向邊緣場效驅動,圓極化光,色序式顯示器, Fast response time,three-dimensional electrode,three-dimensional vertically aligned fringe field switching,circular polarization,color sequential display, |
出版年 : | 2016 |
學位: | 碩士 |
摘要: | 液晶顯示器在我們現今的生活中扮演重要的角色,幾乎所有電子產品都需要顯示器作為人機之間的界面,而快速響應時間的顯示技術一直是我們所追求的目標,在LED產業趨於成熟的狀況下,色序式顯示器也將更有機會成為下一個面板世代的主流。本研究針對具有快速響應時間的垂直配向邊緣場效驅動(Vertically Aligned Fringe Field Switching , VA-FFS)進行模擬分析,希望能夠改善其穿透率表現,雖然雙邊的結構(VA-DFFS)能夠提升穿透率至90%,但由於雙邊結構會有製程上的錯位 (misalignment)問題,嚴重影響光電曲線。因此我們提出了一種單邊的新型三維電極結構(3D VA-FFS),目的是縮減原本VA-FFS在y方向上的穿透率無效區(dead zone),來提升整體的穿透率表現,在研究過程中發現三維電極結構雖然提高了y方向上的穿透率,但是由於對角線dead zone的出現,整體穿透率不但沒有提升,反而嚴重下降。因此我們再加入四分之一波片於三維電極結構的液晶層前後,使得光在行經液晶層時,能以圓極化光的型式通過,藉由改變光的偏振態,我們成功消除了對角線上的穿透率無效區,達成提升穿透率表現的目的。
本研究中也比較了不同電極寬度W與不同電極間距G之下,二維電極結構(2D VA-FFS)與三維電極結構(3D VA-FFS)之光學特性與響應時間,我們希望能夠在不失快速響應時間的特性下,找到改善穿透率的最佳電極尺度。由模擬結果中發現,當電極寬度W增加時,3D VA-FFS能夠同時提升穿透率和降低操作電壓,這是2D VA-FFS所沒有的優勢,然而電極寬度W的增加,卻也降低了液晶分子的響應時間,使得光電特性和響應時間形成一個取捨(trade-off)的關係。此外我們也發現電極間距G的增加,會明顯降低3D VA-FFS的穿透率,因此我們不宜選擇太窄的電極或是太大的間距,而最後我們也作了不同形狀的pixel電極,來分析哪種形狀下能夠將穿透率無效區減至最低,以得到最佳的光學表現。 Nowadays, Liquid Crystal Display plays an important role in our daily life. Almost all the electronic devices require display as their interfaces between people and machines, and the technology of fast response time is always the goal that we pursue. As LED industry getting mature, the color sequential display is more likely to be the mainstream of next generation of panel. In this study, we focus on the simulations of vertically aligned fringe field switching(VA-FFS) with fast response time and dedicate to improve the transmittance performance. Although the bilateral structure(VA-DFFS)can increase the transmittance up to 90%, its misalignment problem will seriously affect the electro-optic curve. Therefore, we proposed a new unilateral three-dimensional electrode structure(3D VA-FFS) to reduce the dead zone along y direction of VA-FFS for increasing the overall performance of transmittance. In the process of the study, we found that the three-dimensional electrode indeed increased the transmittance along y direction. However, because of the diagonal-shaped dead zone above the pixel electrode, the overall transmittance did not increase but decline seriously instead. Therefore we added two quarter-wave films in both front and back side of the cell gap of 3D VA-FFS, and thus the light will be circularly polarized when passing through the cell gap. By changing the polarization state of light, we successfully eliminated the diagonal-shaped dead zone and increased the transmittance. In order to find the best electrode dimension without losing fast response time, we also compared the optical characteristics and response time of 2D VA-FFS with those of 3D VA-FFS under different electrode width and gap. According to the results of simulation, we found that 3D VA-FFS structure can simultaneously enhance the transmittance and lower the operation voltage while the electrode width is increasing, which is an advantage that 2D VA-FFS does not possess. However, the wider the electrode width, the slower the response time of liquid crystal, so it becomes a trade-off between optical characteristics and response time. In addition, we found the transmittance performance will decrease significantly when the electrode gap is increasing, therefore we should not choose the electrode which is too narrow or having too much spacing between them. At the end of the research, we also designed pixel electrode in different shapes to analyze which one can reduce the dead zone to a minimum for the best optical performance. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/76696 |
DOI: | 10.6342/NTU201602505 |
全文授權: | 未授權 |
顯示於系所單位: | 光電工程學研究所 |
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