显示及光通讯用的高△n液晶

高双折射率（△n）液晶常用于彩色顺序式微显示、高亮度胆甾相显示、高对比度PDLC及高速光通讯。本文对△n＞0．4、光吸收弱、光和热稳定性好的液晶,从液晶分子结构进行评述。     

基于Berreman 4×4矩阵对胆甾相液晶Bragg反射带宽的模拟研究

利用Berreman 4×4矩阵和Matlab编程模拟了胆甾相液晶的反射光谱,分析了螺旋数(液晶厚度)、基板的折射率、双折射、折射率色散、固定螺距、梯度螺距和入射角等因素对反射光谱带宽的影响。结果表明,要得到理想的Bragg反射带宽,液晶层的厚度即螺旋数N需达到N≥10;基板折射率会影响最大反射率,基板折射率ng与寻常光折射率no相比,ngno时,最大反射率比较低,ng越小越影响明显,当ng≥no时,具有很好的反射率;折射率的色散和大的入射角会使带宽变窄,而大的双折射Δn和螺距P可以得到较宽的反射带宽,但拓宽效果有限。通过梯度螺距的函数表达式,理论模拟了具有螺距梯度的胆甾相液晶的反射带宽,其对于胆甾相液晶宽波反射的实验研究具有一定的意义。     

显示用胆甾相液晶材料发展现状

介绍了胆甾相液晶显示性能和对液晶材料的要求,分析了近几年高双折射率液晶化合物和手性掺加剂及其胆甾相液晶材料的应用与发展情况,初步阐明了分子结构与液晶性能及其手性掺加剂的HTP值之间的依存关系,为开发新型液晶化合物、手性化合物和胆甾相液晶材料提供了线索。     

胆甾相液晶场致织构变化的偏光显微镜观测

介绍胆甾相液晶的织构和显示应用，给出胆甾相液晶几种织构的偏光显微镜图像。该图像对认识胆甾相液晶的各种织构，理解胆甾相液晶在双稳态显示器的应用原理具有一定的意义。     

公共电极和反射器作互补的单盒式透反射型液晶显示器

给出了一种单盒式透反射型液晶显示器,它采用顶板公共电极和底板的反射器形成互补。这些狭长的公共电极和反射器在透射区域(T区)产生出强劲的纵向电场,而在反射区域(R区)带来微弱的边缘场。无论透射显示模式还是反射显示模式,均给出高的光学效率和良好的匹配灰度。     

公共电极和反射器作互补的单盒式透反射型液晶显示器

给出了一种单盒式透反射型液晶显示器,它采用顶板公共电极和底板的反射器形成互补.这些狭长的公共电极和反射器在透射区域(T区)产生出强劲的纵向电场,而在反射区域(R区)带来微弱的边缘场.无论透射显示模式还是反射显示模式,均给出高的光学效率和良好的匹配灰度.     

快速高双折射率向列相液晶的分子设计与模拟计算

当前液晶自适应光学系统还不能满足校正大气湍流频率(＞40 Hz)的要求,这主要受限于LCOS器件的响应速度(10～20 ms)和位相调制量超过1λ的系统要求.研制新型快速高双折射率向列相液晶材料是解决这一问题的根本方案.本文从分子结构上探讨了影响液晶粘度和双折射率的一般规律.在此基础之上,设计了两种低粘度、高双折射率的液晶分子.通过使用AM1半经验量子化学算法进行了模拟计算,预测了所设计的液晶材料的Δn和Δε值.模拟结果说明,这两种结构的液晶材料能够很好地满足自适应系统的要求.     

含氟三苯二炔类液晶化合物合成及其性质研究

目前,越来越多的液晶应用要求向列相液晶材料具有高双折射率性能。本文合成了5个高双折射率含氟三苯二炔类液晶化合物(Ⅳ),经过IR,1 H NMR,13 C NMR谱图鉴定,这些化合物的分子结构完全正确;通过DSC和POM对其液晶相态测试的实验结果表明该类液晶化合物具有较低的熔点和相对较宽的向列相温度范围(达到100℃左右);对其折光率测试结果表明这些液晶化合物的双折射率(Δn)值在0.47以上,改善液晶光学性能。     

(L)乳酸手性衍生物的含氟二苯乙炔液晶的合成

合成了化合物1-[(1-乙基羰基)-乙基]-4-[4-(2,3,5,6-四氟-4-烷氧基苯基)乙炔基]苯基对苯二甲酸酯(n=5,6,7,8).用热台偏光显微镜及差示量热分析法研究该化合物的液晶性,讨论了氟取代基及桥键对液晶性的影响。所有化合物皆显示互变的胆甾相,黏度低双折射较高,化学稳定,可以用于反射型液晶显示器及自适应光学系统。目的物的最后合成采用Sonogashira交叉偶合法。     

公共电极和反射器作互补的单盒式透反射型液晶显示器

给出了一种单盒式透反射型液晶显示器,它采用顶板公共电极和底板的反射器形成互补.这些狭长的公共电极和反射器在透射区域(T区)产生出强劲的纵向电场,而在反射区域(R区)带来微弱的边缘场.无论透射显示模式还是反射显示模式,均给出高的光学效率和良好的匹配灰度.     

Development of the readout system for waveguide multilayer optical card

Waveguide multilayer optical card （WMOC） is a novel storage device of three-dimensional optical information. An advanced readout system fitting for the WMOC is introduced in this paper. The hardware mainly consists of the light source for reading, WMOC, motorized stages addressing unit, microscope imaging unit, CCD detecting unit and PC controlling ＆ processing unit. The movement of the precision motorized stage is controlled by the computer through Visual Basic （VB） language in software. A control panel is also designed to get the layer address and the page address through which the position of the motorized stages can be changed. The WMOC readout system is easy to manage and the readout result is directly displayed on computer monitor.     

Nanoimprint Lithography -A Next Generation High Volume Lithography Technique

IntroductionNanoimprint Lithography is a well-acknowl-edged low cost, high resolution, large area pattern-ing process. It includes the most promising methods,high-pressure hot embossing lithography (HEL) [2],UV-cured imprinting (UV-NIL) [3] and micro contactprinting (m-CP, MCP) [4]. Curing of the imprintedstructures is either done by subsequent UV-lightexposure in the case of UV-NIL or by cooling downbelow the glass transition temperature of the ther-moplastic material in case of HEL…     

Collinear phase-matching study of terahertz-wave generation via difference frequency mixed in GaAs and Inp

The collinearly phase-matching condition of terahertz-wave generation via difference frequency mixed in GaAs and InP is theoretically studied. In collinear phase-matching, the optimum phase-matching wave hands of these two crystals are calculated. The optimum phase-matching wave bands in GaAs and lnP are 0.95-1.38μm and 0.7-0.96μm respectively. The influence of the wavelength choice of the pump wave on the coherent length in THz-wave tuning is also discussed. The influence of the temperature alteration on the phase-matching and the temperature tuning properties in GaAs crystal are calculated and analyzed. It can serve for the following experiments as a theoretical evidence and a reference as well.     

Effects of the alloy compositions on the phonon-polaritons in ternary mixed crystals

Composition dependence of bulk and surface phonon-polaritons in ternary mixed crystals are studied in the framework of the modified random-element-isodisplacement model and the Bom-Huang approximation. The numerical results for Several Ⅱ - Ⅵ and Ⅲ- Ⅴ compound systems are performed, and the polariton frequencies as functions of the compositions for ternary mixed crystals AlxGa1-xAs, GaPxAS1-x, ZnSxSe1-x, GaAsxSb1-x, GaxIn1-xP, and ZnxCd1-xS as examples are given and discussed. The results show that the dependence of the energies of two branches of bulk phonon-polaritons which have phonon-like characteristics, and surface phonon-polaritons on the compositions of ternary mixed crystals are nonlinear and different from those of the corresponding binary systems.     

Influence of PVK ： NPB hole transporting layer on the characteristics of organic light-emitting devices

A doping system consisting of NPB and PVK is employed as a composite hole transporting layer （CHTL）. By adjusting the component ratio of the doping system, a series of devices with different concentration proportion of PVK ： NPB are constracted. The result shows that doping concentration of NPB enhances the competence of hole transporting ability, and modifies the recombination region of charge as well as affects the surface morphology of doped film. Optimum device with a maximum brightness of 7852 cd/m^2 and a power efficiency of 1.75 lm/W has been obtained by choosing a concentration proportion of PVK ： NPB at 1：3.     

New insert layer structure OLEDs

An insert layer structure organic electroluminescent device（OLED） based on a new luminescent material （Zn（salen）） is fabricated. The configuration of the device is ITO/CuPc/NPD/Zn（salen）/Liq/LiF/A1/CuPc/NPD/Zn（salen）/Liq/LiF/A1. Effective insert electrode layers comprising LiF（1nm）/Al（5 nm） are used as a single semitransparent mirror, and bilayer cathode LiF（1 nm）/A1（100 nm） is used as a reflecting mirror. The two mirrors form a Fabry-Perot microcavity and two emissive units. The maximum brightness and luminous efficiency reach 674 cd/m^2 and 2.652 cd/A, respectively, which are 2.1 and 3.7 times higher than the conventional device, respectively. The superior brightness and luminous efficiency over conventional single-unit devices are attributed to microcavity effect.     

Analysis of error performance on Turbo coded FDPIM

Due to variable symbol length of digital pulse interval modulation（DPIM）, it is difficult to analyze the error performances of Turbo coded DPIM. To solve this problem, a fixed-length digital pulse interval modulation（FDPIM） method is provided. The FDPIM modulation structure is introduced. The packet error rates of uncoded FDPIM are analyzed and compared with that of DPIM. Bit error rates of Turbo coded FDPIM are simulated based on three kinds of analytical models under weak turbulence channel. The results show that packet error rate of uncoded FDPIM is inferior to that of uncoded DPIM. However, FDPIM is easy to be implemented and easy to be combined, with Turbo code for soft-decision because of its fixed length. Besides, the introduction of Turbo code in this modulation can decrease the average power about 10 dBm, which means that it can improve the error performance of the system effectively.     

A method for calculating the center position of collimated light

It is a key problem to accurately calculate beam spots＇ center of measuring the warp by using a collimated laser. A new method, named double geometrical center method （DGCM）, is put forward for the first time. In this method, a plane wave perpendicularly irradiates an aperture stop, and a charge couple device （CCD） is employed to receive the diffraction-beam spots, then the geometrical centers of the fast and the second diffraction-beam spots are calculated respectively, and their mean value is regarded as the center of datum beam. In face of such adverse instances as laser intension distributing defectively, part of the image being saturated, this method can still work well. What＇s more, this method can detect whether an unacceptable error exits in the courses of image receiving, processing and calculating. The experimental results indicate the precision of this method is high.     

Resolution Enhancement Technology:Integrated Process Solutions using OPC

DUV lithography, using the 248 nm wavelength, is a viable manufacturing option for devices with features at 130 nm and less. Given the low kl value of the lithography, integrated process development is a necessary method for achieving acceptable process latitude. The application of assist features for rule based OPC requires the simultaneous optimization of the mask, illumination optics and the resist.Described in this paper are the details involved in optimizing each of these aspects for line and space imaging.A reference pitch is first chosen to determine how the optics will be set. The ideal sigma setting is determined by a simple geometrically derived expression. The inner and outer machine settings are determined, in turn,with the simulation of a figure of merit. The maximum value of the response surface of this FOM occurs at the optimal sigma settings. Experimental confirmation of this is shown in the paper.Assist features are used to modify the aerial image of the more isolated images on the mask. The effect that the diffraction of the scattering bars (SBs) has on the image intensity distribution is explained. Rules for determining the size and placement of SBs are also given.Resist is optimized for use with off-axis illumination and assist features. A general explanation of the material' s effect is discussed along with the affect on the through-pitch bias. The paper culminates with the showing of the lithographic results from the fully optimized system.     

Preparation and Characterization of TaN ALD Precursors

High purity organic-tantalum precursors for thin film ALD TaN were synthesized and characterized.Vapor pressure and thermal stability of these precursors were studied.From the vapor pressure analysis,it was found that TBTEMT has a higher vapor pressure than any other published liquid TaN precursor,including TBTDET,TAITMATA,and IPTDET.Thermal stability of the alkyl groups on the precursors was investigated using a 1H NMR technique.The results indicated that the tertbutylimino group is the most stable group on TBTDET and TBTEMT as compared to the dialkylamido groups.Thermal stability of TaN precursors decreased in the following order:TBTDET ＞ PDMAT ＞ TBTEMT.In conclusion,precursor vapor pressure and thermal stability were tuned by making slight variations in the ligand sphere around the metal center.