Please use this identifier to cite or link to this item:
http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/90520
Title: | 水平配向邊緣場效驅動負型液晶顯示器 在三維結構之模擬研究 Parallel-Aligned Fringe Field Switching Liquid Crystal Display with Negative Dielectric Anisotropy and 3D Electrode Design |
Authors: | 游仕毅 Shi-Yi You |
Advisor: | 蔡永傑 Wing-Kit Choi |
Keyword: | 負型液晶,水平配向邊緣場效驅動,虛擬牆,快速響應,電極結構, negative-type liquid crystal,parallel-aligned fringe field switching,PA-FFS,virtual wall,fast response time,electrode design, |
Publication Year : | 2023 |
Degree: | 碩士 |
Abstract: | 本研究延續蔡永傑博士、邱園竣學長和陳世睿學長對液晶顯示器結構設計的研究,探討負型液晶PA-FFS水平配向邊緣場效驅動顯示器的特性。我們透過改變電極寬度和電極間距來研究透射率和快速響應特性,本研究的主要目的是與邱園竣學長的正型液晶進行比較,並嘗試分析負型液晶在此顯示器中的分子轉動和出光情況。
通過特殊的幹枝結構設計,我們在電極寬度上設計了不同的大小,使部分液晶分子在外加電場作用下偏轉,產生虛擬牆,加速整體液晶分子的響應時間。我們討論了液晶分子在電場作用下的旋轉曲線,並發現分子在轉軸上的差異是光穿透的主要原因,也是虛擬牆位置的重要因素。此外,我們還發現在負型液晶中,虛擬牆在後期轉動時由於缺乏固定的水平方向,會被周圍的液晶分子帶動而產生發光效果。 在論文中,我們探討了不同電極寬度、電極間距和主幹寬度尺寸對整體透射率和響應時間的影響,發現尺寸的匹配和調整對透射率和響應時間有很大的關聯。 從穩態時的液晶分子角度分析,我們發現負型液晶在虛擬牆的角度變化和影響深度方面遠不及正型液晶,但在發光亮度方面卻優於正型液晶。然後,我們分析了負型液晶分子的驅動過程,發現與正型液晶相比,最大的差距在於虛擬牆的水平方向沒有受到電場限制,因此在轉動初期幫助液晶分子轉動後,會被旁邊的液晶分子帶動,實現全範圍發光效果,因此亮度遠超過正型液晶。然而,由於虛擬牆的角度和深度不足,負型液晶無法像正型液晶那樣大幅縮短響應時間。 由於負型液晶具有優異的穿透率,如果我們追求快速響應時間,應該盡可能增加虛擬牆的密度或增加主幹電極寬度(T),並使枝幹電極寬度(W)和枝幹電極間距(L)相似,這樣虛擬牆的密度將更加均勻。 This study builds upon the previous research conducted in our laboratory by Dr. Wing-Kit Choi, senior students Yuan-Chun Chiu and Chen Shirui, on the structural design of PA-FFS (Parallel-Aligned Fringe Field Switching) liquid crystal displays (LCDs). The goal of this research is to investigate the characteristics of a PA-FFS LCD with negative liquid crystal dielectric anisotropy. By varying the electrode width and the distance between electrodes, we investigate the transmittance and response-time properties. The main objective is to compare it with Yuan-Chun Chiu's PA-FFS design which employed positive-type liquid crystal (positive liquid crystal dielectric anisotropy) and analyze the molecular rotation and light transmission behavior in this display. Through a special branch electrode structure design, we use electrodes with different widths to induce the rotation of liquid crystal molecules under an applied electric field. This generates virtual walls and helps accelerate the overall response time of the liquid crystal molecules. By discussing the molecular-rotation-angle curves of the liquid crystal molecules under the electric field, we found that their molecular-rotation angle differences along the rotation axis are the main factors affecting light transmittance and the positioning of virtual walls. We also observed that in PA-FFS with negative-type liquid crystals, the virtual walls during later stages of rotation are not constrained in a fixed horizontal direction, resulting in increased light transmission induced by neighboring liquid crystal molecules. In the thesis, we investigated the effects of different electrode width, electrode spacing and main backbone widths on the overall transmittance and response time. We found that the electrode width, spacing and their ratio can have remarkable effects on light transmission and response time. By analyzing the liquid crystal molecules in the steady state, we found that negative-type liquid crystals can exhibit less variation and less depth of rotation angle in virtual walls regions compared to those of positive-type liquid crystals. They can outperform positive-type liquid crystals in terms of light transmission. By analyzing the switching process of negative-type liquid crystal molecules in PA-FFS, we identified their major difference from positive-type liquid crystals, which is the absence of electric field constraints in the horizontal direction of virtual walls. As a result, after the electric-field driven rotation of liquid crystal molecules in the initial stage, they are then driven by neighboring molecules to achieve almost full-range light transmission, thus surpassing positive-type liquid crystals in brightness. However, due to insufficient angle and depth of virtual walls and other factors such as higher viscosity, PA-FFS with negative-type liquid crystals tends to have slower response time compared to PA-FFS with positive-type liquid crystals. In general, we found that PA-FFS with negative-type liquid crystals can have excellent transmission. If we want to achieve a faster response time, we found that it could be achieved by increasing the density of virtual walls (i.e. by reducing electrode width or spacing) or by increasing the width of the main backbone electrode (T). We also found that it is beneficial to maintain similar width (W) and spacing (L) between branch electrodes, which can help ensure a more uniform density of virtual walls. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/90520 |
DOI: | 10.6342/NTU202303648 |
Fulltext Rights: | 未授權 |
Appears in Collections: | 光電工程學研究所 |
Files in This Item:
File | Size | Format | |
---|---|---|---|
ntu-111-2.pdf Restricted Access | 10.36 MB | Adobe PDF |
Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.