A simple method for measuring the cell gap of a reflective twisted nematic LCD

A simple method is demonstrated for measuring the cell gap of reflective twisted nematic (RTN) liquid crystal (LC) cells. This method utilizes a single laser beam and crossed polarizer configuration such that Fabry-Perot effect and surface reflection are eliminated. Experimental results agree well with theory.     

液晶分子附着能和盒间隙对响应时间的影响

通过理论分析和实验研究液晶分子附着能和液晶盒间隙对响应时间(τ0)的影响。用液晶盒有效间隙法和表面动力学方程法两种方法推出分析公式,由这两种方法推出的结果是一致的。实验数据与简化方程τ0-dx基本拟合(其中d是液晶盒的间隙,x是指数)。在两种极端的(极大或极小)附着能极限下,指数x分别接近2和1。这个结论有助于优化液晶显示器件的应用。     

Applications of multidirectional asymmetrical microlens-array light-control films on reflective liquid-crystal displays for image quality enhancement

The multidirectional asymmetrical microlens-array light-control film (MAMA-LCF) is developed for enhancing the image brightness and contrast ratio of various reflective liquid-crystal displays. By use of index-matching material, the interface reflection is greatly reduced. Through optimized designs, the surface-scattering effect is also suppressed; thus the contrast ratio is much enhanced. From experimental results, the MAMA-LCF leads to a approximately 1.5 x gain in brightness over the MgO standard white and a 15:1 contrast ratio for the reflective color super-twist nematic liquid-crystal display, 2.8 x MgO and a 23:1 contrast ratio for the polymer-dispersed liquid-crystal, and 2.8 x MgO and a 13:1 contrast ratio for the cholesteric liquid-crystal display. Potential applications of this low-cost plastic thin film for reflective liquid-crystal displays are foreseeable.     

Novel Color-Sequential Transflective Liquid Crystal Displays

A novel transflective liquid crystal display architecture and its system driving schemes are proposed. In the reflective mode, the ambient light is used to readout the displayed images. While in the transmissive mode, a color-sequential light emitting diode backlight is used to eliminate the color filters. Under such device configuration, several advantages such as increased brightness and maximized color saturation for both transmissive and reflective modes can be achieved     

Pretilt Angle Effects on Liquid Crystal Response Time

Pretilt angle effect on liquid crystal dynamics is analyzed theoretically. Analytical expressions are derived to describe liquid crystal response time under nonzero pretilt angle conditions. The theoretical analysis is confirmed experimentally using vertically aligned liquid crystal cells. This finding quantitatively correlates pretilt angles with liquid crystal response time. This study improves the understanding of the liquid crystal dynamic process which is helpful for optimizing liquid crystal response time.     

采用反射式液晶显示器和有机电致发光器件前后双置组合而成的高环境对比度显示器

一种高环境对比度(A-CR)和大开口率的显示器已经从理论上证明,并通过把一个正常显黑反射型显示器(NB-RLCD)和一个有机电致发光器件(OLED)堆垛的实验加以证明。这种前后双置(以下称为tandem型)的器件组合可以分别在明亮或昏暗的环境下切换NB-RLCD模式或OLED模式。RLCD的正常显黑特性也可以提升OLED模式工作时的A-CR性能。为了在RLCD模式下获得更好的图像品质,一个复杂并且具有传输功能的结构被用于消除镜面反射和提高可视角至CR﹥2:1超过55°的锥面可视角度。另外,这样的结构也可以提高OLED49.4%的表面量子效率。在我们的实验里,忽略环境亮度因素并使A-CR保持在100:1以上。     

Transflective liquid crystal displays

In this review paper, a detailed overview of the transflective liquid crystal display (LCD) technology is presented. We first introduce the transflector classifications based on their composition and properties. Then, in reviewing the development history, we investigate the mainstream transflective LCDs, including their operating principles, advantages, and disadvantages. Finally, the image quality issues of transflective LCDs, such as color balance, image brightness, and viewing angle, are discussed.     

一种利用反射电极偏压的半反半透LCD

介绍了一种VA模式反射电极偏压的常黑单盒厚半反半透LCD.在透射区,形成连续且均匀的贯穿液晶层的电场;而在反射区,电场则主要由电极表面形状控制.由此,可使透射区的位相延迟约是反射区的2倍.这样一种半反半透LCD不论透射区还是反射区都有很高的光透过率(＞90%),同时二者灰阶特性重合度也很好.     

一种利用反射电极偏压的半反半透LCD

介绍了一种VA模式反射电极偏压的常黑单盒厚半反半透LCD。在透射区,形成连续且均匀的贯穿液晶层的电场;而在反射区,电场则主要由电极表面形状控制。由此,可使透射区的位相延迟约是反射区的2倍。这样一种半反半透LCD不论透射区还是反射区都有很高的光透过率(>90%),同时二者灰阶特性重合度也很好。     

用于高对比度反射式显示的扭曲PDLC

开发了一种采用扭曲边界聚合物分散型液晶(TPDLC)的高亮度、高对比度反射式显示器。与普通的PDLC膜相比，TPDLC不依赖于偏振光，具有高的对比度和低的工作电压。还演示了一种利用染料掺杂TPDLC的黑白笔段式字母反射式显示器。