利用二維/三維連續電極結構之低電壓高穿透率藍相液晶顯示器

Abstract

藍相液晶顯示器為目前液晶顯示器中相當熱門的研究題目，因為其擁有亞毫秒的響應時間以及不需要配向層製成容易。但藍相液晶顯示器然有其缺點，其高操作電壓與低穿透率為主要的問題，因此近期許多文獻藉由設計不同電極結構來改善藍相液晶顯示器的高操作電壓與低穿透率問題。但大多文獻所設計的電極結構皆是改變X-Z方向上的電極參數的二維結構，本論文一開始提出的三維結構則是設計三維度的電極結構，希望能減少二維結構在Y方向上的穿透率無效區(dead zone)。 一開始我們參考了三種不同的二維電極結構，設計了三種不同的三維電極結構，發現在三維電極結構中會出現中央暗態區因此影響了三維結構的穿透率表現。經過分析後，在最佳穿透率上，皆是二維結構來的較佳。但三維結構仍有其優勢，在電極間距較小時，穿透率則會優於相對應的二維結構。 接著我們參考了鑽石狀(Diamond-shape)電極結構，設計出連續型的特殊結構希望能減少中央暗態區，首先我們先將連續型結構以及鑽石狀結構做比較。在尖頂鑽石結構與鑽石狀的比較中，在大部分的電極間距下( )穿透率皆高於鑽石狀結構；而在複合式鑽石結構與鑽石狀結構的比較下，複合式鑽石結構都有較好的穿透率與操作電壓。 最後將相對應的二維、三維以及連續型電極結構做互相比較。在二維、三維三角形、尖頂鑽石的比較中，二維三角形的穿透率仍是最佳，而三維三角形在低操作電壓下有較好的穿透率。在二維、三維複合式梯形、複合式鑽石結構的比較中，二維複合式梯形有最佳的穿透率；在低操作電壓下三維複合式梯形有較佳的穿透率。而連續型電極結構觀察其穿透率與電極間距的影響，整體來說連續型結構在大部分的電極間距下都能維持在高穿透率。

Blue phase liquid crystal display is a popular research topic for the liquid crystal display. Because of its sub-millisecond response time and its display without alignment layer that make it be fabricated easier. However, the primary problems of blue phase liquid crystal are low transmittance and high operating voltage. Many theses aim to design different electrode structures to improve the high operating voltage and low transmittance. Most theses aim to design two-dimension electrode structures about parameters on X-Z direction. Therefore, we design the three-dimension electrode structures and hope that new structures can reduce the dead zone on y-direction. At first, we refer to three kinds of 2D electrode structures to design three kinds of 3D electrode structures. We discover that 3D electrodes have the problem of central dead zone and the problem influence the transmittance of the display. After the analysis, the 2D electrodes still have the highest transmittance. However, 3D electrodes also have their advantage. 3D electrodes have higher transmittance at low operating voltage if the electrode gap is small. Then we refer to Diamond-shape electrodes to design continuous electrodes to reduce the central dead zone on expectation so we compare continuous electrodes with Diamond-shape electrodes first. The result is that the pointed diamond electrodes have higher transmittance in comparison with Diamond-shape electrodes generally ( ). The enhanced Diamond electrodes have higher transmittance and lower operation voltage in comparison with Diamond-shape electrodes. In the end, we compare continuous electrodes with 2D and 3D electrodes. Among 2D, 3D triangle and pointed diamond electrodes, 2D triangle electrodes have the highest transmittance with large gap but 3D triangle electrodes have the higher transmittance at low voltage with small gap. Pointed diamond electrodes have high transmittance over 75% with most electrode gaps. Among 2D, 3D enhanced trapezoid and enhanced diamond electrodes, 2D enhanced trapezoid electrodes have the highest transmittance with large gap but 3D enhanced trapezoid electrodes have the higher transmittance at low voltage with small gap. Enhanced diamond electrodes have high transmittance over 80% with most electrode gaps. In terms of transmittance vs electrode gaps, continuous electrodes combine the features of 2D and 3D electrodes. Continuous electrodes have less sensitivity on electrode gaps compared to 2D and 3D electrodes with reasonably high transmittance.