扭曲向列相液晶电光效应的微观机理研究

为了探究液晶电光效应的微观机理,以扭曲向列相液晶为研究对象,对液晶分子的变化情况进行了理论分析。运用连续体弹性理论分析了扭曲向列相液晶分子的指向矢取向变化,并对液晶电光效应曲线不同区间范围液晶微观结构的变化进行了系统分析。结果表明:液晶分子在零电场条件下的扭曲是均匀的;当外加电场大于某一值时,液晶分子开始转向,液晶产生电光效应。研究结果对液晶显示器件设计和深入理解液晶电光效应机理具有一定的指导意义。     

液晶光阀的偏光显示特性分析

讨论了液晶光阀的偏光扭曲向列性效应, 分析了液晶光阀中液晶分子在交流电场作用下重新取向后的扭曲, 测量了TB3639型液晶光阀在特定的频率连续改变外加交流电压条件下,液晶分子重新取向后的扭曲角度以及液晶光阀的电光特性。测量结果表明,在外加电压连续改变时,入射线偏振光的透射率呈现连续非线性变化,这种非线性变化可以由液晶分子的扭曲量来改变。同时液晶分子180°的扭曲使得液晶光阀具有较陡的电光特性曲线,这对于多通道矩阵寻址方式的液晶光阀而言在矩阵显示中可有更多的通道寻址线和更高的对比度。     

液晶显示用取向材料聚甲基丙烯酸肉桂酰氧基乙酯的光控取向研究

通过实验研究了光聚合物材料聚甲基丙烯酸肉桂酰氧基乙酯（ＣＥＭＣ）的光化学反应过程, 以及对液晶材料ＬＣ－６７１０Ａ 的取向能力． 通过原子力显微镜（ＡＦＭ）观察了取向层表面在光化学反应前后的变化, 测量了光控取向膜液晶盒中液晶分子的预倾角及单面光控取向扭曲向列液晶显示器（ＴＮＬＣＤ）的电光特性和时间响应特性曲线, 研究了液晶分子排列取向的机理．     

液晶显示用取向材料聚甲基丙烯酸肉柱酰氧基乙酯的光控取向研究

通过实验研究了光聚合物材料聚甲基丙烯酸肉柱酰氧基乙酯（ＣＥＭＣ）的光化学反应过程,以及对液晶材料ＬＣ－６７０１Ａ的取向能力。通过原子力显微镜（ＡＦＭ）观察了取向层表面在光化学反应前后的变化,测量了光控了以向膜液晶盒中液晶分子的预倾角及单面光控取向扭曲现列液晶显示器（ＴＮＬＣＤ）的电光特性和时间响应特性曲线,研究了液晶分子排列取向的机理。     

全漏光导波技术确定液晶材料的挠曲电系数

利用全漏光导波技术,测量负性向列相液晶材料MS-N01300-000的展曲和弯曲挠曲电系数之和.根据液晶弹性和多层光学理论得到同一电压下不同挠曲电系数的反射率随内角(入射到液晶层角度)的理论变化曲线.实验中,将液晶材料灌注到混合排列向列相液晶盒中,在液晶盒上分别加交流电和直流电,采用全漏光导波技术得到反映液晶指向矢分布的液晶波导反射率随内角变化曲线.实验发现,由于液晶挠曲电作用,同一电压值下反射率随内角变化曲线发生微小移动.对比理论与实验曲线,由曲线移动距离得到MS-N01300-000液晶材料展曲和弯曲挠曲电系数之和为2.5×10-11 C/m.     

苯乙烯基吡啶类液晶化合物的分子结构及相变过程的光谱研究

通过本乙烯基吡啶和不同脂肪羧酸间的氢键作用构成液晶的方法具有合成路线灵活、简便、易于变化的特点,本文通过变温红外光谱对做为质子受体的苯乙烯基吡啶粉液晶化合物的分子结构和相变过程中分子排列的变化进行了研究,结果表明在液晶分子中象羰基这样的偶极矩较大的极性基团,对分子所处的相态分子间的相互排列比较敏感。在红外光谱中羰基伸缩振动的变化可以看作是液晶分子相态转变的标志。     

液晶全漏导模透射率的实验研究

实验研究了由棱镜、折射率匹配液及扭曲排列和垂直排列向列相液晶盒构成的液晶全漏导模的透射率。随着施加在液晶盒上的电压不同,得到了依赖于角度变化的透射率（包括偏振保存和偏振转换）的实验曲线。这些曲线由液晶指向矢在液晶盒中的分布直接控制,由此可以证实液晶全漏导模透射率同样可以用来探索液晶盒内部的细微变化。     

液晶全漏导模的实验研究

夹在2块玻璃基板之间的液晶可以形成波导层,光在其间传播形成导模.通过全漏波导技术,分别对扭曲向列相液晶盒施加不同电压进行测试,得到了依赖于角度变化的反射率(包括偏振保存和偏振转换)实验曲线.液晶指向矢的变化将直接影响反射率变化,验证了液晶全漏波导技术在探索液晶盒内部细微变化方面是有效手段.     

聚甲基丙烯酸肉桂酰氧基乙酯的光化学反应在液晶分子排列取向中的作用

研究了光聚合物材料聚甲基丙烯酸肉桂酰氧基乙酯(CEMC)对液晶材料LC-6710A的取向作用,取向层表面在光化学反应前后的变化;测量了光控取向膜液晶盒中液晶分子的预倾角及单面光控取向扭曲向列液晶显示器(TNLCD)的电光特性和时间响应特性,研究了这种材料的光化学反应过程,以及液晶分子排列取向的机理.     

液晶的转动粘质系数的测试原理与方法(英文)

液晶的转动粘质度是液晶用于显示和通讯的重要物理参量.本文设计开发了基于微机的液晶参数测试光学系统,在该系统上研究了液晶的转动粘质系数的测试原理与方法:通过测试液晶盒在偏置电压下相位驰预时间,推导出转动粘质系数的值.测试Merck公司的E7液晶的转动粘质系数随温度变化的曲线,进行了理论拟合,测试结果与理论符合得很好.通过分析另一系统对液晶介质常数随温度变化的曲线的测试结果,验证了该测试原理与方法的正确性.该测试方法具有简单、自动化的特点.     

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.     

Nonlinear molecular deformations and solitons in a nematic liquid crystal

We studied nonlinear molecular deformations in a nematic liquid crystal with homeotropically aligned molecules and hard boundaries. As the basic dynamical equation for the director axis of the liquid crystal resembles the Landau-Lifshitz equation representing spin dynamics in a one dimensional classical continuum isotropic Heisenberg ferromagnetic spin chain, we invoke here the space curve formalism and the stereographic projection technique used in the case of the Heisenberg spin chain. Under space curve mapping, the director dynamics with elastic deformation is found to be governed by a perturbed nonlinear Schrödinger equation. A multiple-scale perturbation analysis brings out perturbed solitons to represent molecular deformations in the nematic liquid crystal. However, when a constant electric field is applied, the director dynamics is expressed under stereographic projection and the molecular deformations are found to be governed by periodic and localized static planar director configurations. A linear stability analysis on the static planar configurations shows that the system exhibits stable deformations.     

Two-dimensional electron crystal in magnetic field. Topological phase transitions and stability region.

The phase diagram of a 2-dim. electron system in the magnetic field $\text{H}$ is analyzed. We obtain ab initio the free energy F{U_iκ} of a deformed electron crystal when the long-range Coulomb forces and $\text{H}$ are taken into account. Using F{u_iκ} we find H-dependent interaction between the dislocations and the curve of the topological melting due to the dissociation of dislocation pairs. The topological melting curve for H → ∞ asimptotically approaches to the melting curve of a classical crystal. This result is obtained using Feynman variational technique as well. We examine also the electron liquid crystal phase and the stability region of a 2-dim. crystal at $\text{H}$ ≠ 0. The first-order phase transitions from the crystal and liquid crystal to the isotropic liquid are predicted to take place in a definite region of the phase diagram. We find the increase of the crystal and liquid crystal region on the T-n phase diagram with H increase. The various phenomenological stability criteria are ånaylzed.     

液晶电控调谐滤波器的研究

理论分析了液晶调谐滤波器的调谐原理,利用岛津UV-23101分光光度计,通过对BL-009型向列相液晶透射比的测试,分析了可见光波段液晶透射比随电场的变化情况,作出了入射光波长从400~800 nm时液晶透射比随电压变化的关系曲线,并就氩离子激光器两条谱线488 nm和514.5 nm进行了提取.     

A liquid crystal thermography calibration with true color image processing

Liquid crystal thermography is a high-resolution, non-intrusive optical technique for full-field temperature measurement. We present the detailed calibration data for the thermochromic liquid crystal （TLC） with a useful range of 41-60 ℃. The calibration is done with true color image processing by using an isothermal calibrator. The hue-temperature curve of the TLC is obtained, and the measurement uncertainty is analyzed. Combined with the image noise reduction technique of a 5×5 median filter, the measurement accuracy of the liquid crystal thermography can be significantly improved by approximately 57.1%.     

基于迭代修正的液晶相控阵激光雷达波控数据获取

分析了影响液晶相控阵波控数据获取的几个关键因素,在此基础上通过计算期望相位面与实际相位面的相位差,提出一种基于迭代修正的波控数据获取方法,该方法可通过改变加载在液晶阵列上的参考电压或改变参考相位面实现。讨论了算法关键参数的选择。通过仿真进一步研究了液晶特性曲线范围和高斯初始相位对波控数据获取的影响。仿真结果表明:该方法能获得比较准确的波控数据;液晶特性曲线范围对波控数据的准确获取非常重要,当曲线范围较大时,液晶相控阵可补偿高斯光束引入相位的影响。     

Design of tunable wavelength microcavity organic electroluminescent diode with liquid crystal

A novel designed method for tunable wavelength microcavity organic electroluminescent diode (MOLED) based on the birefringence of liquid crystal was presented. By modulated the refractive index of liquid crystal, the device could radiate with different wavelength continuously. The simulated result showed that the tunable range could reach to 60 nm and the full width of half maximum is 5.5 nm. The device could be applied to wavelength converter and tunable light source.     

Metastable extensions of phase equilibrium lines and singular points of simple substance

The thermodynamic properties of crystal, liquid, and gas in the stable and metastable states have been determined by molecular dynamics simulation of a system of 2048 Lennard-Jones particles. The spinodals of a superheated crystal, a superheated liquid, and a supersaturated vapor have been approximated; the spinodal for a supercooled liquid turns out to be nonexistent. The liquid-vapor, liquid-crystal, and crystal-vapor equilibrium curves and their extensions beyond the triple point have been calculated. It has been shown that, as distinct from the metastable extension of the saturation curve, which terminates at the zero isotherm, the metastable melting and sublimation curves terminate at, respectively, the stretched liquid and superheated crystal spinodals. The properties of the critical end points of metastable equilibrium of extended phases are considered.     

Random lasing in dye-doped polymer dispersed liquid crystal film

A dye-doped polymer-dispersed liquid crystal film was designed and fabricated,and random lasing action was studied.A mixture of laser dye,nematic liquid crystal,chiral dopant,and PVA was used to prepare the dye-doped polymer-dispersed liquid crystal film by means of microcapsules.Scanning electron microscopy analysis showed that most liquid crystal droplets in the polymer matrix ranged from 30 μm to 40 μm,the size of the liquid crystal droplets was small.Under frequency doubled 532 nm Nd:YAG laser-pumped optical excitation,a plurality of discrete and sharp random laser radiation peaks could be measured in the range of 575–590 nm.The line-width of the lasing peak was 0.2 nm and the threshold of the random lasing was 9 m J.Under heating,the emission peaks of random lasing disappeared.By detecting the emission light spot energy distribution,the mechanism of radiation was found to be random lasing.The random lasing radiation mechanism was then analyzed and discussed.Experimental results indicated that the size of the liquid crystal droplets is the decisive factor that influences the lasing mechanism.The surface anchor role can be ignored when the size of the liquid crystal droplets in the polymer matrix is small,which is beneficial to form multiple scattering.The transmission path of photons is similar to that in a ring cavity,providing feedback to obtain random lasing output.