聚合物分散液晶光栅的衍射特性的研究

报道了一种由聚合物分散液晶膜与具有周期性条状电极结构板结合的新型光栅器件，借助于聚合物分散液晶膜的电光特性，这种栅对入射光的散射或衍射取决于对其施加的电压，即它是电场可调的，实验结果显示出当驱动电压超过器件器件阈值电压时，衍射光的强度和衍射斑的可见级次被电场调制，而且它能入射光的线性偏振态变为椭圆偏振态。     

新型聚合物分散液晶相位光栅的制备

把具有光敏特性的预聚物与向列相液晶按一定比例混合 ,注入表面经过取向处理的液晶盒中。以紫外灯为光源 ,通过光掩膜法 ,使混合物在光场的引发下发生相分离 ,形成液晶 /聚合物相位光栅。由于相分离后液晶在取向膜的作用下沿液晶盒面方向旋转 180° ,克服了传统液晶光栅器件对入射光偏振方向的依赖 ,提高了光的有效利用率。采用光学显微镜和He Ne激光器进行测试 ,结果表明所制样品具有较好的栅结构 ,其衍射效率不受入射光偏振方向的影响且具有电场可调性。该光栅制作方法简便 ,驱动电压低 ,在光通信器件、衍射光学、投影显示、光开关等领域有广泛的应用前景     

Diffraction Properties of Field-Adjustable Polymer Network Stabilized Liquid Crystal Grating

A new diffraction grating mode has been proposed. This grating is formed by applying of a spatially periodic electric field to a polymer network stabilized uniformly aligned liquid crystal layer. Due to the electro-optic properties of the polymer network stabilized liquid crystal layer, the grating type is electrically adjustable, i.e. it presents amplitude, phase or amplitude-phase type depending on the applied voltages. Experimental results show that the number of visible diffraction orders can be adjusted easily, and even be closed at the same time. The detail fabrication process and experimental results will be presented.     

Diffraction Properties of Field Adjustable Polymer Network Stabilized Liquid Crystal Grating

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Phase Modulation Characteristics Analysis of Optically-Addressed Parallel-Aligned Nematic Liquid Crystal Phase-Only Spatial Light Modulator Combined with a Liquid Crystal Display

An optically addressed parallel-aligned nematic-liquid-crystal spatial light modulator (PAL-SLM) has been studied as a dynamic phase-only light modulation device. The phase modulation characteristics of the PAL-SLM using a liquid crystal display (LCD) as an addressing mask were investigated by analyzing diffraction efficiencies resulting from binary gratings projected from the LCD. A more than 2π phase-only modulation depth was achieved. The highest first-order diffraction efficiency of approximately 38% was also obtained; this is close to the theoretical limit. The experimental results of diffraction efficiencies depending on the phase modulation depth are in good agreement with the simulation for the system operation.     

Lattice Boltzmann Simulation of 3D Nematic Liquid Crystal near Phase Transition

Phase transition between nematic and isotropic liquid crystal is a very weak first order phase transition.We avoid to use the normal Landau-de Gennes‘s free energy that reduces a strong first order transition,and set up a data base of free energy calculated by means of Tao-Sheng-Lin‘s extended molecular field theory that can explain the experiments of the equilibrium properties of nematic liquid crystal very well.Then we use the free energy method of lattice Boltzmann developed by Oxford group to study the phase decomposition,pattern formation in the flow of the liquid crystal near transition temperature.     

纳米银掺杂的高效率全息聚合物分散液晶光栅制备

报道了一种基于掺杂纳米银聚合物分散液晶(PDLC)材料的高衍射率全息电控光栅的制备及特性。通过在原有聚合物分散液晶材料体系中添加适量的纳米银颗粒以制备体全息光栅,实验研究了掺杂不同质量比的纳米银颗粒对全息聚合物分散液晶(H-PDLC)体光栅的衍射效率、驱动阈值电压、响应时间的影响。实验结果表明,通过掺杂纳米银材料,能够优化聚合物和液晶两相分离结构,使聚合物与液晶分离更加彻底,显著提高H-PDLC体光栅的一级衍射效率,同时能改善体光栅的电光特性,缩短响应时间。初步分析表明,由于纳米银颗粒的表面等离子体效应和体系折射率匹配的优化改善了H-PDLC光栅的特性。     

用偏光显微术研究聚合物分散液晶压光效应膜

制备出大液晶微滴的具有压光效应的聚合物分散液晶膜,给出样品按压前后偏光显微镜对比照片.提出压缩液晶微滴模型,采用Fortran软件模拟计算了压光效应液晶微滴双折射透光率分布,用Origin软件作图,计算结果绘图与偏光显微镜图片一致.定义按压后液晶微滴圆球变扁球的扁平度,计算按压后序参数与扁平度的关系,说明按压作用使液晶...     

电控聚合物分散液晶变焦全息透镜制作

介绍了相位型全息聚合物分散液晶(PDLC)材料全息透镜,在电场作用下液晶微滴折射率逐渐与聚合物折射率匹配,实现透镜电控变焦。研究了微米尺寸和纳米尺寸液晶微滴聚合物分散液晶材料配方特性和微观结构。采用优化纳米尺寸材料配方制作5~6μm聚合物分散液晶盒,采用离轴式平面波和球面波干涉全息写入光路,成功制作电控变焦聚合物分散液晶全息透镜样品。该透镜样品焦距为20 mm,能够正一级衍射放大成像。实现“0”,“1”变焦的驱动电压阈值为60 V。并进一步提出了基于聚合物分散液晶电控变焦元件集成叠加技术实现电控变焦光学成像系统的技术思路。     

垂直定向液晶光阀中液晶电光特性的理论分析

采用 ４×４ 矩阵法模拟计算了垂直定向液晶光阀的电光特性, 从理论上分析了影响液晶光阀电光特性的因素。根据向列液晶的弹性连续体理论及边界力矩平衡方程, 求出了垂直定向向列液晶在液晶界面之间相互作用锚泊能为有限值时的液晶指向矢分布。根据指向矢分布计算了一定外加电场下液晶光阀的电光特性, 并和锚泊能为无限大时的特性进行了比较和分析     

Thermally Stimulated Depolarization Currents and Optical Transmission Studies on UV Cured Polymer Dispersed Liquid Crystal Films

Polymer-dispersed-liquid-crystal films were obtained using the photopolymerization-induced-phase-separation method. The thermally stimulated depolarization current measurements indicate a space-charge-limited current. Conduction of electronic type was proven and the activation energy, specific to the conduction process, was calculated. Optical measurements have been performed simultaneously with the measurements of thermally stimulated currents and the nematic-isotropic phase transition was detected by the switch of the optical transmission. The change of the optical transmission versus applied a.c. voltage was the indication for the on-off switch behavior, useful in electro-optic applications.     

新型聚合物分散液晶材料研制的电控体全息光栅

报道了聚合物分散液晶材料全息光栅元件的研制，并研究了聚合物分散液晶材料光栅的衍射特性及电控开关特性。该光栅结合了聚合物分散液晶材料的电控光开关特性和全息光栅的优点，在光通信器件、可调窗口、液晶显示等领域具有广泛的应用前景和巨大的潜在生产力。     

聚合物分散液晶增强散射的理想模型

介绍聚合物分散液晶技术新进展,应用光学原理对液晶微滴增强散射问题进行研究,提出液晶微滴最佳间距判据,液晶微滴间隔处聚合物材料光学厚度满足增反膜条件;提出液晶微滴最佳直径判据,液晶微滴直径满足双折射相消干涉条件;提出聚合物与液晶最佳配比的计算方法,应用晶体学原子堆积致密度知识给出最佳配比的计算结果.建立一种聚合物分散液晶增强散射的理想模型,进而从更基本的光学原理出发对异常散射理论模拟计算和实验上确定的液晶微滴最佳直径和聚合物与液晶最佳配比问题给出十分简单明确的理论解释.     

高精度纯相位液晶空间光调制器的研究

研制了平行排列液晶空间光调制器（LC SLM）。论述了平行排列液晶相位调制的理论,进行了计算模拟。对液晶空间光调制器相位调制特性和振幅调制特性进行了测量,实验结果表明,在整个灰度级范围内是纯相位调制的空间光调制器,并且调制的范围可达到0．6λ。在ZYGO菲佐干涉仪上进行了精度特性的研究,得到了非常好的结果,在1cm^2的面积上,进行了畸变波前的调制,其精度峰谷值可达0．098λ,均方根值可达0．017λ。在此精度的基础上产生了π相位差的栅结构,证明了这种液晶空间光调制器可以很好的进行相位调制。     

便携式电控聚合物分散液晶全息透镜的电源及结构设计

根据聚合物分散液晶材料的光电特性及需要,在研究基于聚合物分散液晶光电器件时必须设计合适的电源驱动系统。介绍了在电控聚合物分散液晶全息透镜器件研制中,将电池输出的直流低压升高变频到70～100V、1000Hz频率交流高电压的电路系统设计。并介绍了变焦透镜装置总体结构的机械设计。实验结果表明,该电源设计能够满足聚合物分散液晶全息透镜器件中的液晶分子光轴驱动的需要,并能实现器件的小型化和便捷式。     

聚合物弥散液晶材料在1550nm的电光特性研究

实验研究了不同配方及工艺条件下,聚合物弥散液晶（PDLC）材料在1550nm处的电控光透射特性。由此筛选合适的配方和工艺,研制了聚合物弥散液晶电控可调光衰减器样品。实验说明,在1550nm工作点,50％左右合适的液晶含量的聚合物弥散液晶样品能够获得更好的电控光学性能。采用配方质量比ω（DHPA）：ω（E7）：ω（RB）：ω（NVP）：ω（NPG）=100：100：3：2：1．5的配方,制作在1550nm工作的聚合物弥散液晶光衰减器样品。经检测,输入光源为1550mm,223μW时,器件插入损耗为2．3dB,衰减调节范围为13dB,线性工作区域为20～70V。     

聚合物网络稳定液晶的电光偏振片

制备了一种散射偏振片,它是由非晶态单体形成的聚合物网络、向列液晶和涂有聚酰亚胺的ＩＴＯ玻璃基板组成。聚酰亚胺被反向平行摩擦,液晶分子则沿摩擦方向取向,并被单体形成的网络所稳定。根据聚合物网络液晶的电光特性可知。入射偏振光束被散射或透射相应地取决于其偏振方向平行还是生趣于基板的摩擦方向。平行时,光的散射强度通过电场可被强烈地调节;垂直时,光的透过率很高,几乎不依赖施加的电场。这种偏振器件具有低的驱动     

CdS-CdSe液晶光阀光电特性分析

对CdS－CdSe液晶光阀的结构及特性进行了分析，对其性能参数进行了测试，此光阀能较好地应用于大屏幕投影显示系统中。     

Structure and Properties of Glass Fiber Reinforced Polypropylene/Liquid Crystal Polymer Blends

A liquid crystal polymer (LCP) was used to improve the physical properties of glass fiber reinforced polypropylene (GFRPP). The LCP was beneficial to improve the mechanical and heat resistant properties of the GFRPP/LCP composite. Compared with the GFRPP with 30% (w%) glass fiber (GF), the yield strength and the impact strength for the GFRPP/LCP composites increased by 62.7% and 18.1%, respectively, with a 6.8°C increase in the Vicat softening temperature for a 5% LCP addition to the GFRPP composites. The crystallinity of the polypropylene (PP) matrix for the GFRPP/LCP composites increased for 5% LCP and then decreased with increasing the LCP content. The γ-phase crystals for the PP matrix occurred in the shear layer of the injection molded GFRPP/LCP samples. The improved adhesion interface between the GF and the PP matrix was beneficial to reinforce and toughen the GFRPP/LCP composites with a small addition of the LCP.     

聚合物网络稳定液晶膜的制备与研究

实验发现在液晶中添加少量的预聚物单体,利用光聚合诱导相分离的方法可以形成反型显示模式的聚合物网络稳定液晶膜。该膜在平时呈现透明态,在电场的调节下呈散射态。本文观察了在不同光照时间、不同光强下制得样品的聚合物网络织构,分析了在聚合过程中形成网络的形状、大小与致密程度,并对实验结果进行了相关的讨论。