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1.
应变液晶的负压光效应和反式压光效应   总被引:2,自引:0,他引:2       下载免费PDF全文
范志新  黎振远  周璇  张志东 《物理学报》2014,63(14):146101-146101
介绍聚合物分散液晶和应变液晶概念,给出聚合物分散液晶调光玻璃的"正压光效应"、"负压光效应"和"反式压光效应"三种效应定义.实验制备出负压光效应和反式压光效应新型应变调光玻璃样品,测试样品散射态雾度90%以上,半透明态透光率接近30%.用偏光显微术研究压光效应原理,表明对样品施加垂面按压或拉伸的应力诱导作用会引起液晶微滴中液晶分子具有某些特殊排列方式,导致样品光学性质发生显著变化.建立垂面拉伸液晶微滴模型,计算模拟所绘出的图形与偏光显微镜照片独特花样十分相似,进而合理解释了实验现象.应变液晶压光效应研究具有聚合物分散液晶基础研究意义和开发非电控调光玻璃的实际应用价值.  相似文献   

2.
用偏光显微术研究聚合物分散液晶压光效应膜   总被引:4,自引:0,他引:4  
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...  相似文献   

3.
李文萃  刘永刚  宣丽 《物理学报》2011,60(4):46101-046101
为了提高全息聚合物分散液晶光栅的衍射效率并降低其驱动电压,改善光栅的电光特性,研究了表面平行摩擦取向对全息聚合物分散液晶光栅电光特性的影响.理论分析认为,改善相分离结构和降低液晶微滴之间的有序度差异是优化光栅电光特性的根本所在.由于进行表面取向处理后的液晶和单体之间达到扩散匹配,使得相分离的程度大幅提高,在衍射能力增强的同时驱动电压也实现了大幅下降,而且,表面取向作用也使光栅内的液晶分子均匀排列,降低了液晶微滴之间的有序度差异,从而减少了光栅的散射损失.实验结果表明:进行取向处理后的光栅其衍射效率由传统光 关键词: 全息聚合物分散液晶 衍射效率 驱动电压  相似文献   

4.
报道了一种聚合物分散液晶(PDLC)膜在压力作用下从散射膜变为透明膜的实验现象,建议称之为PDLC膜的压光效应.介绍了与压光效应相关的PDLC的应变液晶、剪切液晶和拉伸液晶等概念;给出PDLC压光效应膜样品照片,偏光显微镜照片,电光特性光谱分析和压光效应光谱分析.提出PDLC膜压光效应的原理猜想,给出对PDLC膜光学性...  相似文献   

5.
电控聚合物分散液晶变焦全息透镜制作   总被引:4,自引:1,他引:4  
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。  相似文献   

6.
剪切聚合物分散液晶散射偏光特性   总被引:12,自引:2,他引:10  
介绍了拉伸聚合物分散液晶和散射偏光片概念,实验制备了剪切聚合物分散液晶样品,给出了对聚合物分散液晶样品施加剪切应力的偏光特性光谱分析.实验结果表明,吸收偏光片前置和后置样品的散射偏光效果相同,样品在绿光550nm波长处最大透光率T//~60%,最小透光率T┴~10%,偏振度P~70%.实验结果对于其他散射偏光片具有普遍...  相似文献   

7.
剪切液晶散射偏光玻璃的研制与应用   总被引:1,自引:0,他引:1  
范志新  高攀 《光学技术》2014,40(4):367-370
介绍了聚合物分散液晶、剪切液晶、散射偏光片以及透明投影屏幕等概念。实验制备了剪切液晶散射偏光玻璃样品,样品由两张玻璃夹层聚合物分散液晶膜在紫外光固化过程中施加剪切应力制成。实验给出了样品偏光显微镜照片和透光率以及雾度随透光轴与入射偏振光偏振方向夹角的变化曲线。剪切液晶散射偏光玻璃外观半透明,存在透光轴。散射偏光玻璃与吸收偏光片组合具有调光窗功能,与单片液晶投影机或单片硅上液晶投影机配套还能用作背投影成像效果十分清晰的透明投影屏幕。  相似文献   

8.
介绍了一种基于聚合物分散液晶材料的连续调焦电控透镜.在聚合物分散液晶盒的上表面电极上刻蚀圆孔,形成一个非对称电极,在液晶盒上下极板之间,诱发一个非均匀电场,从而引起聚合物分散液晶材料的折射率非均匀分布,形成电控变焦透镜.阐述了聚合物分散液晶可调焦透镜的基本原理,分析了透镜孔径对聚合物分散液晶透镜焦距的影响,在直径3mm和6mm的圆孔条件下,分别测量了透镜焦距随电压的变化关系.结果表明:电压从50V加到170V的过程中,透镜焦距逐渐减短,刻蚀3mm圆孔的聚合物分散液晶盒焦距从1.361 63m到0.429 21m,刻蚀6mm圆孔的聚合物分散液晶盒焦距从1.769 92m到0.548 43m.  相似文献   

9.
随机激光的阈值与体系内的散射强度存在密切关系。高折射率二氧化钛(TiO_2)纳米颗粒与染料掺杂聚合物分散液晶(DDPDLC)均匀混合后,由于液晶微滴与TiO_2纳米颗粒之间的强散射作用,DDPPLC的随机激光具有更低的激光发射阈值,并且随TiO_2纳米颗粒的掺杂浓度而变化;在优化TiO_2纳米颗粒掺杂浓度的基础上,DDPDLC的发射阈值为270μJ/cm~2,线宽下降至0.08nm;温度实验证明了PDLC结构的散射是产生随机激光的主要工作机制,在TiO_2纳米颗粒掺杂后,DDPDLC样品依然保证了良好的可调性。  相似文献   

10.
基于Mie理论研究了球形光学微腔的光学特性,通过计算内场和散射场展开系数随着尺寸分布的变化确定了共振发生的位置,给出了计算球形微腔散射场和内场的计算公式,并数值模拟了结构共振情形下的内场分布情况,分析了微腔内的光振荡特性.  相似文献   

11.
We considered light scattering by a polydisperse ensemble of droplets of a nematic liquid crystal. To model light scattering by a monolayer of polymer-dispersed spherical droplets of a nematic liquid crystal with cylindrical symmetry of its internal structure, we proposed a semianalytical modeling method. The method is based on interference approximation of the theory of multiple wave scattering, anomalous diffraction approximation, and effective-medium approximation. The method takes into account cooperative optical effects in concentrated, partially ordered layers and can be used to analyze the small-angle structure of the intensity of scattered radiation in relation to the concentration, size, polydispersity of liquid crystal droplets, orientation of their optical axes, and refractive indices of the liquid crystal and polymer. The obtained relations can be applied to solving direct and inverse problems of light scattering in composite liquid crystal materials using data of polarization measurements. We present graphical results of solving the direct problem for components of the polarization vector of scattered wave. These results illustrate the formation of an angular structure for monolayers with a high concentration of polydisperse droplets of the liquid crystal in the range of small scattering angles (0 < θ s ≤ 8°).  相似文献   

12.
Shian Li M  Fuh AY  Wu ST 《Optics letters》2011,36(19):3864-3866
This study demonstrates an optical switch of the diffractive light from a body-centered tetragonal photonic crystal based on holographic polymer-dispersed liquid crystals that are fabricated using two-beam interference with multiple exposures. The liquid crystal-rich regions form the lattice points of the PC, which contains a liquid crystal/azo-dye mixture. The concentration of the cis isomer changes under laser light exposure; this change, in turn, modulates the effective index of the LCs, and then switches diffractive light.  相似文献   

13.
聚合物网络稳定液晶的电光偏振片   总被引:2,自引:0,他引:2  
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  相似文献   

14.
An optical method is proposed to reconstruct the order parameter for liquid crystal droplets with rigidly fixed poles. The method is based on measurements of the coherent transmission coefficient of a oneatom layer (monolayer) of polymer-dispersed liquid crystal droplets and on comparison with the results of the solution of the direct problem. In solving the direct problem for determining the coherent transmission coefficient of the polymer-dispersed liquid crystal monolayer, the anomalous diffraction approximation and the approximation of the effective refractive indices for liquid crystal droplets were used. The capabilities of the method are illustrated by the reconstruction of one component of the diagonal tensor of the droplet order parameter.  相似文献   

15.
Ono H  Kawatsuki N 《Optics letters》1997,22(15):1144-1146
We present a novel type of photorefractive polymer-dispersed liquid crystal (PDLC) that contains a polymer, low-molecular liquid crystals (LC's), and a photoconductive sensitizer. Photorefractivity is demonstrated by two-beam-coupling experiments with an external dc field. This material shows highly sensitive photorefractivity, and a purely refractive-index grating (Dn >/= 3.0 x 10(-3)) is generated by irradiation of interference light (lambda=632.8 nm) . The grating in the photorefractive PDLC's shows strong anisotropy, and the dynamics depends strongly on the composition. In the case of a 40:60 weight ratio of polymer:LC's, the photorefractive PDLC's present a stable memory effect.  相似文献   

16.
This work describes the morphology and electro-optical properties of polymer-dispersed liquid crystals (PDLCs). These composites consist of the nematic liquid crystal E7, filled with different types of inorganic nanoparticles in Norland optical adhesive (NOA65) polymer matrices. Natural clays CL120 (trade name: CN-C34 with higher cation exchange capacity CEC) and CL42 (trade name: PK802 with lower CEC) are used as various inorganic nanofillers. Wide angle X-ray diffraction was exploited to examine the dispersion of the inorganic nanoparticles in PDLCs. The morphology of liquid crystal droplets in PDLCs is investigated by the field emission scanning electron microscope (FESEM) and transmission electron microscope (TEM) as well. Transmittance vs. applied voltage is measured to study the electro-optical properties and the response times of the PDLCs. It is suggested that doping with inorganic nanoparticles in PDLCs effectively reduces the driving voltage and improves the electro-optical characteristics.  相似文献   

17.
We have described the method of analyzing and reporting on the results of calculation of the small-angle structure of radiation scattered by a polymer-dispersed liquid crystal film with electrically controlled interfacial anchoring. The method is based on the interference approximation of the wave scattering theory and the hard disk model. Scattering from an individual liquid crystal droplet has been described using the anomalous diffraction approximation extended to the case of droplets with uniform and nonuniform interface anchoring at the droplet–polymer boundary. The director field structure in an individual droplet is determined from the solution of the problem of minimizing the volume density of the free energy. The electrooptical effect of symmetry breaking in the angular distribution of scattered radiation has been analyzed. This effect means that the intensities of radiation scattered within angles +θ s and–θ s relative to the direction of illumination in the scattering plane can be different. The effect is of the interference origin and is associated with asymmetry of the phase shift of the wavefront of an incident wave from individual parts of the droplet, which appears due to asymmetry of the director field structure in the droplet, caused by nonuniform anchoring of liquid crystal molecules with the polymer on its surface. This effect is analyzed in the case of normal illumination of the film depending on the interfacial anchoring at the liquid crystal–polymer interface, the orientation of the optical axes of droplets, their concentration, sizes, anisometry, and polydispersity.  相似文献   

18.
Lee GH  Hwang KY  Jang JE  Jin YW  Lee SY  Jung JE 《Optics letters》2011,36(5):754-756
The optical properties and the theoretical prediction of color optical shutter with dye-doped polymer network liquid crystal (PNLC) were investigated. The view-angle dependence of reflectance according to the bias conditions showed distinctive characteristics, which could be explained from the effects of dye absorption and path length. It was also shown that the thickness dependence of reflectance was strongly influenced by the light-scattering coefficient. Our experimental results matched up well with the theoretical prediction based on the light scattering of liquid crystals in polymer network and the absorption of dichroic dye. This work indicates potential to improve the optical device using dye-doped liquid crystal-polymer composite.  相似文献   

19.
This article reports a comparative study of the phase separation process in a polymer-dispersed liquid crystal, based on a Metropolis Monte Carlo simulation study of three lattice systems. We propose a model for the different processes occurring in the formation of polymer-dispersed liquid crystals (PDLCs). The mechanism of PDLC is studied as a function of quench temperature, concentration and degree of polymerization of liquid crystals and polymers. The obtained resultant phase diagrams of the three systems are approximated and compared with the Flory-Huggins theory, and show a good agreement. It has been observed in the simulation results that among all the three systems, the 40 × 40 × 40 lattice showed the most accurate, reliable and stable results.   相似文献   

20.
光散射聚合物导光板的材料参数设计   总被引:1,自引:0,他引:1  
光散射聚合物(HSOT)导光板与传统导光板相比具有亮度更高均匀性更好等优点,其性能受材料的影响十分明显。通过蒙特卡罗方法进行光学仿真模拟考察不同材料的导光板照明光线的均匀性差别,研究了光散射聚合物导光板的光学性能受其中掺杂粒子的材料折射率、粒径、浓度的影响规律。通过比较不同材料参数的聚合物导光板的光学性能差别,总结出光散射聚合物导光板的材料设计方法。  相似文献   

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