用偏光织构及透射光谱分析液晶器件的老化

对一组台式计算器液晶显示器进行了光辐照,研究了光辐照对液晶显示器件显示品质的影响。采用偏光显微镜观察到了辐照后液晶的偏光织构的变化,液晶中出现了平行的条纹状织构和失去消光作用的黑洞,随着接受光辐照时间的增加,黑洞数量越来越多,面积越来越大。通过由计算机控制的双光束紫外-可见分光光度计测试了透射光谱的变化,发现其透射率随着接受光辐照时间的增加而降低。分析结果表明,条纹状织构和黑洞的出现是由于液晶分子结构在紫外线的照射下发生了变化所致,失去消光作用的黑洞是导致液晶器件透射率持续下降的主要原因。     

液晶显示器防紫外光谱特性分析

近年来液晶显示器件朝着彩色化和大型化方向发展 ,户外应用也将越来越多 ,紫外光对液晶器件产生影响也逐渐显现出来 ,防紫外光将越显重要。通过测量ITO玻璃及偏光片对各波段紫外光的光谱特性 ,分析比较一般偏光片 (LN 12 0 5T)和防紫外偏光片 (F 12 2 5DU)的紫外透射光谱 ,偏光片F 12 2 5DU对紫外线有比较好的吸收 ,能挡住各种波长的紫外光。使用防紫外F 12 2 5DU偏光片的新型液晶显示器 ,能较好的解除紫外的影响 ,从而提高了户外型液晶显示器产品的性能。     

新型液晶光学相控阵的特性研究

将液晶作为平板光波导的上包层,构建了液晶光学相控阵器件.根据Frank-Oseen液晶连续体弹性形变理论与光栅衍射理论,研究分析了基于这种新型结构下液晶光学相控阵的传输特性,输出衍射特性和其它性能特性.研究结果表明,器件的传输电控相位延迟可以实现更大的光程差;阵列电极周期数目、电极宽度、电极间隔宽度等结构参量对器件的输出衍射光束的光强分布和半峰值全宽度影响很大,同时光束扫描的可行性得到论证;器件的响应时间提高了一个数量级,且其色散性能获得改善.为以后研制新型液晶光学相控阵提供了理论基础与技术设计依据.     

液晶电光特性研究

随着近几年液晶显示技术在诸多领域的广泛应用和新技术的推出,人们一直致力于改善液晶器件显示性能的研究。在液晶显示器应用中,电光特性是一个很重要的参数,介绍了采用激光测量的方法获得液晶的电光特性、阈值电压及视角特性。分析了液晶分子在交流电场作用下重新取向后的扭曲特性,测试了不同电压下液晶分子的透光率和扭曲角度,结果表明:该方法是可行的,向列相液晶具有0.92 V较低阈值电压和较为陡峭的电光曲线,水平方向上在-60~+50有较好的视角特性,垂直方向上在-40~+20有较好的视角特性。该结论为偏光器件的设计与制作提供了依据。     

平行-混合排列透反式液晶显示模式的原理研究

为了同时获得具有高透射率和反射率的液晶显示器,提出了一种采用平行排列模式与混合排列模式相搭配的单倍盒间距的透反式液晶显示模式.基于液晶盒的初始取向,反射区为混合排列模式,其光程差为透射区平行排列模式的一半.利用单轴膜补偿的方法可以实现宽光谱响应,并且采用不同相位延迟的补偿膜可以使器件工作于常黑模式和常白模式.模拟结果表明:两种工作模式均可实现宽光谱响应,透射与反射电光响应曲线基本趋于一致;在40°方位角度范围内具有很好的可视特性,无灰度反转.     

单运放辐照后的退火

在辐照试验研究中，经常面临退火问题。有时在低剂量率下需要对试验器件进行长时间的辐照才能达到一定的辐照总剂量，而在长时间的辐照过程中就存在退火的影响；在进行辐照筛选时，辐照后的器件需要退火后性能基本恢复才能正常使用；在进行某些辐照研究中，器件可能需要重复多次的辐照／退火过程。如果对器件的退火特性不清楚，以上试验的结果就是不可靠的。     

平行-混合排列透反式液晶显示模式的原理研究

为了同时获得具有高透射率和反射率的液晶显示器,提出了一种采用平行排列模式与混合排列模式相搭配的单倍盒间距的透反式液晶显示模式.基于液晶盒的初始取向,反射区为混合排列模式,其光程差为透射区平行排列模式的一半.利用单轴膜补偿的方法可以实现宽光谱响应,并且采用不同相位延迟的补偿膜可以使器件工作于常黑模式和常白模式.模拟结果表明：两种工作模式均可实现宽光谱响应,透射与反射电光响应曲线基本趋于一致;在40°方位角度范围内具有很好的可视特性,无灰度反转.     

一种互补——MOS片驱动的液晶显示器——阈值电压低,对比度高

日本日立公司日立研究实验室研制出一种新的液晶显示器,阈值电压底,对比度高是其两个特点。当用于电池或计算器时,该器件能有效地由互补—MOS片直接驱动。这种显示器的阈值电压约为5V,当电压为与互补—MOS片匹配的8V那一档时,达到了60∶1的峰值对比度。 新器件用的液晶是在向列型混合液晶中加进约0.6％重量比的胆甾相液晶。这种液晶配方导致光散射机构的改变,从而降低阈值电压。在此以前,曾经在有记忆功能的显示器中用过向列型/胆甾型混合液晶,与它们相比,新器件所用的液晶中所注入的胆甾     

一种反射式扭曲向列型液晶显示优化设计的新方法

基于扭曲向列型液晶的显示器件通过调制光波的偏振态实现显示的目的,因此光波的偏振状态在其中起了极为关键的作用.本文结合琼斯矩阵和表示光波偏振态的斯托克斯参量j-circle方法,提出了一种优化反射式扭曲向列型液晶显示器件的新方法.该方法与原有的空间参量方法不同的是采用了追踪光波在传播过程中偏振态变化的办法得到反射式液晶显示器件中各光学元件的参数.该方法简单直观并且可以对多个参数同时进行优化,实现了显示性能的最优化设计并得到了新的显示模式.     

彩色滤光膜硅覆液晶微显示器的三维光学建模

本文针对彩色滤光膜(color filter, CF)硅覆液晶(liquid crystal on silicon, LCoS)微显示器件(microdisplay)中的微型彩色像素建立了三维光学模型. 这个三维光学建模主要分为三个过程, 即彩色液晶器件的机电特性分析, 利用扩展琼斯矩阵(extended Jones matrix)计算器件的光反射率, 以及采用标准RGB(standard RGB, sRGB)协议将CF-LCoS微显示阵列中各像素点的光反射特性还原成彩色图像. 通过上述过程建立的三维光学模型用于CF-LCoS的光学特性研究并与实验数据进行比较. 比较结果显示, 模拟得到的CF-LCoS微显示器的光学特性与实验结果非常符合.     

A Color Holographic Reconstruction System by Time Division Multiplexing with Reference Lights of Laser

3D-TV systems by holography technique have been studied in the world. In this paper, we report a color holographic reconstruction system by time division multiplexing method with reference lights of laser. The method can reconstruct a color holographic image by switching reference lights of red, green and blue colors at certain intervals. We can observe a color holographic image using red and green lasers as the reference lights, a high minute liquid crystal display (LCD) panel as a spatial light modulator (SLM) and electro-shutters as the shuttering device of the laser lights in the optical system. This approach has some advantages. Namely, the structure of the optical system can be simple and the number of LCD panels in the optical system can be decreased.     

基于LED背光源区域控制的LCD系统色域分析

介绍了液晶显示(LCD)系统普遍使用的色域计算方法。针对LCD系统的色域主要由背光源的光谱特性、彩膜的光谱透过率特性和液晶面板的特性三个方面的因素决定,采用LED作为背光源来提高系统整体的色彩表现能力,利用色度学的方法,通过对LED背光源光谱的分析计算,比较了有无区域控制的背光源经过彩膜后系统色域的大小,并分析了液晶面板对比度的变化分别对两种模式下背光源色域的影响情况。分析和计算结果表明：采用区域控制的LED背光源可以改善由于彩膜性能的不完善所引起的再现三基色色彩饱和度降低的现象,同时该模式下系统色域受液晶面板对比度变化的影响很小,即降低了系统色域对彩膜性能和液晶面板性能的要求,因此对于提高现有LCD系统的色域具有非常重要的意义。     

A new high-resolution femtosecond pulse shaper

A novel liquid crystal display (LCD) with 640 stripes was successfully implemented and investigated for femtosecond pulse shaping. As compared to previously used devices, the large active area allows for operation in high-power laser systems. The increased number of pixels greatly enlarges the manifold of accessible pulse modulations, making the device an ideal tool for coherent control experiments and optical information processing. Received: 1 February 2001 / Published online: 21 March 2001     

Extraction of Waveguided Llight by Anisotropic Scattering Polarizer in Organic Electroluminescent Devices

We demonstrated that the anisotropic scattering polarizer (ASP) laminated to a glass substrate surface increased the optical efficiency of an organic electroluminescent (EL) device for liquid crystal display (LCD) backlight applications. ASP was prepared by drawing the liquid crystal polymer (LCP) dispersed poly(carbonate) film and extracted the emitting light trapped in the substrate of an organic EL device involved in polarization selectivity. Light extraction ability and polarization selectivity were changed by thickness of the electron transporting layer (ETL) of the organic EL device. Optical efficiency of a 60 nm thick ETL device through absorbing polarizer was not much improved by the lamination of ASP, whereas low efficiency of a 120 nm thick ETL device was greatly improved by this lamination due to extraction of the waveguided light as a substantially polarized emission. Although the degree of increase for the 120 nm thick ETL device was very large, the final optical efficiency was less than or only comparable to that of the thinner device. In 90 nm thick ETL device, however, the lamination of ASP increased the optical efficiency by a factor of 1.2–1.3 against a 60 nm thick ETL device. © 2004 The Optical Society of Japan     

SLM-based maskless lithography for TFT-LCD

Maskless photolithographic methods have been developed using digital micromirror devices (DMDs) and grating light valves (GLVs), which are spatial light modulators (SLMs), because liquid crystal display (LCD) panel industries spend huge amounts of money for the cost of TFT (thin film resist)-LCD photomasks. The technology has been developed for implementing 2 μm bitmap resolutions, which is a requirement for the lithographic process, though the process time is still slow for mass-production system. A DMD-based maskless exposure uses 405 nm-wavelength semiconductor lasers as an illumination source and optical engines that contain DMDs, micro lens arrays (MLAs), and projection lenses. A GLV-based system consists of UV lasers and optical write engines, which are constructed with the GLV, grating optics, and imaging lenses. Since many companies have been trying to overcome the time limitations, the maskless technology will be realized in the LCD industry in near future.     

改进宽银幕投影显示照明系统的设计方法

照明系统是投影显示系统的重要组成部分,决定着整个系统的亮度和照明均匀性。复眼系统是一种常见的液晶投影显示系统照明结构。传统的复眼照明系统设计方法中,复眼小透镜具有与液晶板相同的长宽比,可以获得能量利用率和均匀性都比较好的照明光斑。但研究发现,利用这种方法设计宽银幕投影显示设备的复眼照明系统,会引起一定的光能损失。针对这一问题,通过对复眼系统设计理论的分析和对实际复眼照明系统的模拟,创新性地提出了在照明系统中引入柱面透镜改变复眼小透镜的长宽比的设计方法,能够有效的提高投影系统能量利用率。模拟计算结果表明,引入柱面透镜的复眼照明系统与传统方法设计的复眼系统相比,能量利用率可以提高5％到10％。     

液晶相息图用于光学检测

根据液晶的动态响应和位相调制特性,研究了一种利用液晶显示器进行光学检测的检测方法.实验中,把液晶显示器改造为纯位相的空间光调制器,并测定了它的位相调制特性.实验测得：改造后的液晶显示器可实现1 λ(λ=632.8 nm)的调制量.通过引入相息图的方法,实现了液晶空间光调制器的大位相调制量.并产生了调制量为3.4 λ的球面波.最后,利用液晶显示器检测了凸透镜的前表面.检测结果发现,干涉条纹为平行直条纹且PV值为0.32λ.     

Improved measurement of dynamic modulation transfer functions on display using pursuit camera method based on wavelet-denoising method

A new method was developed for studying dynamic modulation transfer functions (DMTFs) of liquid crystal display (LCD) based on the slanted edge method, improved wavelet-denoise (IWD) method, and Fourier transformation. Measurements were made for capturing the images of moving step-edge patterns on the display by a slightly tilted pursuit camera. The scanning-rate and contrast-dependent DMTFs of a LCD were demonstrated, and the corresponding parameters such as blurred edge width (BEW), spatial sharpness, and motion picture response time (MPRT) were calculated from the DMTF curves. A simple linear relationship between these parameters was found. The properties of a cathode ray tube (CRT) display were also measured for comparison with those of the LCD.     

Homogeneous-aligned high-transmission and fast-response liquid crystal display with three-layer electrodes

A homogeneous-aligned, high-transmission, and fast-response liquid crystal display (LCD) with three-layer electrodes is proposed. The molecules of liquid crystals are more inclined to rotate above and between the pixel electrodes. This induces a much higher transmission than that of the cell driven by the fringe field switching method and a wide viewing angle simultaneously because of the combined fringe and in-plane electric fields. Furthermore, a trigger pulse voltage is applied between the top and common electrodes to forcibly align the liquid crystal molecules vertically to show the transient dark state, which results in a very fast turn-off time (～1 ms). With high degree of transmission and fast response time, this kind of LCD is a potential candidate for large LCD panels.