排序方式: 共有121条查询结果,搜索用时 15 毫秒
1.
平行排列液晶器件的波前调制特性 总被引:18,自引:17,他引:1
设计了一种新型的平行排列液晶相位调制器(LC PM),可在纯相位的模式下进行相位调制,研究了液晶相位调制器的光学特性,理论上给予了分析.对畸变波前进行了调制,在1 cm2的校正面积上,调制后的准确度PV(peak to valley)值接近λ/15(λ=0.6328 μm),RMS(Root Means Square)可达到λ/100,斯特列尔比SR (Strehl Ratio)达到0.989.改变了传统的扭曲向列液晶器件难于进行纯相位调制和得到高准确度调制的缺点,达到了理想的效果. 相似文献
2.
实验研究了子孔径光学检测的拼接准确度.实验选取9个子孔径进行拼接,同时利用ZYGO干涉仪来测量子孔径和整个被检面的表面面形.实验发现,测量基准子孔径和整个被检面的时间间隔对子孔径拼接准确度的评价存在严重影响.为此,重点研究了产生影响的原因并提出了消除测量基准子孔径和整个被测面时间间隙影响的方法.最后,利用该方法研究了子孔径重叠面积对拼接准确度的影响.结果显示,当重叠面积比为7%时,PV和RMS的拼接误差分别为0.03λ(λ=632.8 nm) 和 0.01λ,并且重叠面积比和拼接准确度呈近似线性关系. 相似文献
3.
Effect of Molecular Weight on Liquid Crystal Photoalignment by Photosensitive Polyester Containing Thrifluoromethyl Moieties 下载免费PDF全文
We investigate the liquid-crystal (LC) alignment direction on photoalignment films formed from photosensitive polyester containing thrifluoromethyl moieties (PPDA) with various molecular weights by crossed polarized optical microscopy. It is found that LC alignment behaviour changes with molecular weight of PPDA. The LC alignment on PPDA irradiated films with the highest molecular weight is homogeneous, while those with low and intermediate molecular weights are homeotropic. However, surface morphologies show weak dependence on molecular weight. The surfaces are smooth and there is no clear morphological anisotropy on these aligned films observed by an atomic force microscope. The surface energies of the irradiated films are also measured by using an indirect contact-angle method where both surface energy and its polar component, increase with increasing molecular weight. Different polar surface energies can be considered as a main reason for different alignment characteristics. 相似文献
4.
Rotational viscosity of a liquid crystal mixture: a fully atomistic molecular dynamics study 下载免费PDF全文
Fully atomistic molecular dynamics (MD) simulations at 293, 303 and
313~K have been performed for the four-component liquid crystal
mixture, E7, using the software package Material Studio. Order
parameters and orientational time correlation functions (TCFs) were
calculated from MD trajectories. The rotational viscosity
coefficients (RVCs) of the mixture were calculated using the
Nemtsov--Zakharov and Fialkowski methods based on
statistical-mechanical approaches. Temperature dependences of RVC
and density were discussed in detail. Reasonable agreement between
the simulated and experimental values was found. 相似文献
5.
6.
为提高自适应光学人眼波像差校正和视网膜成像效果,研究了人眼动态波像差的特性。利用采样频率为300Hz、曝光时间为3ms的哈特曼传感器,搭建波像差探测系统。误差分析和模拟人眼实验表明,该系统对动态波像差的测量误差均方根(RMS)均值仅为0.01λ。人眼波像差探测结果表明,人眼存在150Hz以上的波像差,可能对自适应波像差校正造成影响。这种影响可通过延长探测和成像曝光时间的方法来抑制。为了达到衍射极限,对于稳定盯视状态下的人眼,3ms探测曝光、探测校正周期不超过45ms的自适应系统,其校正残差均方根在λ/14以下;当曝光时间增加到6ms时,该周期可放宽至62ms。研究了倾斜像差的波动对成像的影响,确定了高分辨率人眼眼底成像中,成像曝光时间最长不能超过9ms。上述结果表明,将自适应光学视网膜成像的探测曝光与成像曝光时间均定在6ms左右,可获得更好的校正和成像效果。 相似文献
7.
This paper proposes a new Zernike modal gray map
reconstruction algorithm used in the nematic liquid crystal adaptive
optics system. Firstly, the new modal algorithm is described. Secondly,
a single loop correction experiment was conducted, and it showed
that the modal method has a higher precision in gray map
reconstruction than the widely used slope method. Finally, the
contrast close-loop correction experiment was conducted to correct
static aberration in the laboratory. The experimental results showed
that the average peak to valley (PV) and root mean square (RMS) of
the wavefront corrected by mode method were reduced from
2.501\lambda (\lambda =633~nm) and 0.610\lambda to
0.0334\lambda and 0.00845\lambda , respectively. The corrected
PV and RMS were much smaller than those of 0.173\lambda and
0.048\lambda by slope method. The Strehl ratio and modulation
transfer function of the system corrected by mode method were much
closer to diffraction limit than with slope method. These results
indicate that the mode method can take good advantage of the large
number of pixels of the liquid crystal corrector to realize high
correction precision. 相似文献
8.
在全原子力场模型的基础上,对向列液晶nCB(4-n-alkyl-4'-cyano biphenyls,n=5-8)进行了等压等温NPT系综下的分子动力学(MD)模拟.对MD的轨迹分析得到了二阶和四阶序参数以及描述液晶分子翻转运动的取向时间相关函数(TCF),并通过一个近似的单指函数对TCF拟合得到了相关时间.在此基础上,计算了nCB(n=5-8)的旋转扩散系数(Rotat ional diffusion coefficient,RDC).利用基于统计力学模型的Nemtsov-Zakharov方法和Fialkowski方法,分别计算了它们的旋转黏度系数(rotational viscosity coefficient,RVC),进而分别讨论了RVC,RDC和相关时间的奇偶效应.与文献中的实验结果比较表明,该方法得到了合理的计算结果和一致的奇偶效应. 相似文献
9.
纳米晶钛酸铅表面态对介电性能的影响 总被引:3,自引:0,他引:3
将醋酸铅、钛酸四丁酯和硬脂酸在熔融状态下混合均匀后置于冷水浴中,使其凝固成凝胶,经不同温度焙烧,制成纳米晶PbTiO3.用X射线衍射光谱、红外光谱对产物进行表征.采用X射线光电子能谱和表面光电压谱对纳米晶PbTiO3表面状态分析,发现材料表面的不完整性主要是由氧空位造成.暴露在粒子表面的主要是金属离子.随着晶粒尺寸的减小,材料表面氧空位缺陷浓度增加,表面光伏效应增强,谱带变宽.纳米晶PbTiO3材料的表面状态对其极化性质有着重要的影响,使其静态介电常数远大于常规材料的静态介电常数. 相似文献
10.
通过包铜过程的分析,了解到包铜反应主要是表面化学吸附反应,ZnS颗粒表面状况对生成的CuxS性质影响很大,据此设计了淬火包铜工艺,并得到形成功率较低,抗老化性能好的DCEL粉.本文初步分析了淬火生成的CuxS相,认为它的初态处于一种高度无序状击,经一段时间可自然发生某种相变.新相比较稳定,从而可能抑制由Cu+迁移造成的老化. 相似文献