Analysis of natural frequency for imaging interface in liquid lens

Transmission beam can be modulated at the liquid-liquid interface inside an electrowetting liquid lens.The fluctuation characteristics of the interface has a decisive effect on the beam modulation.A closed cylinder in capillary constant scale is analyzed and the natural frequencies of a flat interface are obtained using capillary wave hydrodynamics.Results in modes 0 and 1 are in good agreement with previous experiments in the literature.The influences of the radius,the height ratio and the height-to-diameter ratio of a liquid lens on the interface eigenfrequencies are analyzed.

Liquid crystal Fresnel lens display

A novel see-through display with a liquid crystal lens array was proposed.A liquid crystal Fresnel lens display（LCFLD） with a holographic screen was demonstrated.The proposed display system has high efficiency,simple fabrication,and low manufacturing cost due to the absence of a polarizer and color filter.

OPTICAL OPTIMIZATION FOR LIQUID CRYSTAL TEST BY LASER-CCD SYSTEM

For the narrowband of liner charge-coupled device （CCD） receiver and the imaging rule that cylindrical lens system can compress round facula into narrow and long one, the system is simplified and light force can concentrate on a strip facula, Considered the effective CCD length and selection of lens parameters, the system can be optimized. Correspondingly to the CCD pixels, the ray is composed of much angle information. By widening the parallel ray or increasing the lens aperture, luminous flux can be ensured when oblique incidence. Meanwhile, the effective working range can also be improved. Based on the experimental data, cylindrical system could be applied in accurate angle measurement. It has been proved feasible that the cylindrical system can be used in anchor behavior study for liquid crystal （LC） case. The low-power He-Ne laser cylindrical system can carry out the previous effect in high power laser spherical system.

A Depth Sensor Based on Transient Property of Liquid Crystal Lens

The property of maintaining the lens state of the liquid crystal(LC)lens during the switching between positive and negative lens states is made use of in the fast acquirement of multi-focus images without magnification change.A depth from focus(DFF)pipeline that can generate a low-error depth map and an all-in-focus image is proposed.The depth of the scene is then obtained via DFF pipeline from the captured images.The depth sensor proposed in this paper has the advantages of simple structure,low cost,and long service life.

同心圆环电极结构的液晶透镜特性

液晶透镜的液晶层内相位分布通常不是理想的抛物线结构,这给液晶透镜的成像应用带来限制。本文采用基于液晶的线性响应区域设计的电极结构制作液晶透镜,通过对液晶透镜工作时的前信息进行分析,测出液晶透镜的光焦度和光学像差。在由相机模块和执行调焦功能的液晶透镜组成的成像系统中,通过对经过液晶透镜后所成的图像进行定量研究。分析成像系统形成的ISO12233图标的图像,获得成像系统的分辨能力。结果表明,该液晶透镜驱动简单,光焦度与驱动电压差符合线性关系,可在-4.9~+5.2 D范围调节,同时具有低于0.05λ的光学像差。在成像系统的应用中,在对主镜头分辨能力影响不大的情况下,该液晶透镜表现出优异的调焦性能。

连续变焦的聚合物分散液晶电控透镜

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.

可编程菲涅耳相位透镜应用于多平面全息投影

研究了基于菲涅耳相位透镜实现多平面全息投影的方法,采用硅基液晶相位调制器建立了多平面全息投影系统.首先,利用可编程菲涅耳相位透镜代替傅里叶透镜,将计算机生成的相位全息图与菲涅耳透镜的相位结合;其次,基于时分复用和空分复用原理提出了加载菲涅耳相位透镜与相位全息图到相位空间光调制器上的两种方法;最后,讨论了在多平面全息投影中每个单一平面实现旋转物体动态360°视角显示的方法.实验结果表明:在距离硅基液晶分别为500、800、1 100和1 400mm处的四个重构平面可以获得全息投影图像;通过动态地改变菲涅耳相位透镜的焦距,可以实现多平面全息投影.

液晶偏振变焦透镜组合设计

具有可变焦能力的透镜在成像、传感和检测等领域扮演着重要角色。本文通过研究液晶偏振透镜的光学特性,设计出多点变焦的液晶偏振透镜变焦系统。液晶偏振透镜是一种利用液晶分子指向矢(光学各向异性轴)特定的空间排列,产生特定几何相位差从而达到波前控制效果的光学器件,对于左/右旋圆偏振光分别表现为正/负透镜效果。利用液晶偏振透镜的偏振特性及液晶分子受电场调制的性质,本文设计出由一片普通正透镜、一片可调谐液晶波片和两片液晶偏振透镜组成的液晶偏振变焦透镜组合,在特定的偏振入射光下,可以实现7个焦距的改变。同时,通过优化透镜焦距、间隔等参数,可以使变焦透镜组合实现等间隔变焦等功能。实验结果显示,在633 nm圆偏振光下,利用自主制备的液晶偏振透镜组成的液晶偏振变焦透镜组合系统成功实现了7个焦距的变焦功能,同时变焦距离基本符合预期且部分焦距(前6个)实现了等间隔分布,充分验证了利用液晶偏振透镜实现多点变焦的可行性。

液体变焦透镜的驱动及其特性研究

液体透镜相对固体透镜最大的优点是无需使用伺服电机等大型驱动装置，便可实现变焦。通过对国内外液体变焦技术的研究进行总结，依据不同的变焦机理对液体透镜进行分类，把液体变焦形式分为变曲率半径型和变内部液体型。变曲率半径型液体透镜的驱动原理繁多，分别进行详细介绍。主要从变焦机理，设计结构，透镜的成像优缺点等方面分析。最后，基于液体透镜研究现状，提出一种新型变焦液体透镜结构来改善温度场对液体透镜性能的影响。

新型甲襞微循环成像装置的研制

目前临床上可用的甲襞微循环监测装置存在诸多问题,如结构庞大、不便于携带。且使用时由于患者的身体发生移动,导致采集的视频很难稳定,给医生的观察带来很大的困难。该研究基于SDF成像原理和液体镜片技术研制出一种小型的甲襞微循环图像采集装置。该装置使用环形照明装置安装在成像系统前端,并根据人体手指的特征,对系统结构进行总体设计。该装置体积小、便于携带、易固定在人体指端,能通过控制器进行快速对焦成像,且采集的甲襞微循环图像质量高,可以促进甲襞微循环装置在床旁的使用,是医护人员观察患者微循环状况的有效工具。

Influence of the Maximum Blur Radius on Depth Sensor Based on Liquid Crystal Lens

This paper describes how the maximum blur radius affects the depth results by depth from the defocus(DFD)method based on liquid crystal(LC)lens.Boundary frequency is determined by the maximum blur radius.It is found that if the maximum blur radius used in the calculation is larger than the real value,the depth resolution obtained is reduced;on the other hand,if one smaller than the real value is used,the depth resolution in the middle range of the scene is increased,but errors occur in the near and far planes.Using the maximum blur radius close to the real one results in the best depth results.

Design and optimization of nano-antenna for thermal ablation of liver cancer cells

One method of cancer therapy is to utilize nano-antenna for thermal ablation.In this method,the electromagnetic waves emitted from the nano-antenna are absorbed by the tissue and lead to heating of cancer cells.If temperature of cancer cells reaches a threshold,they will begin to die.For this purpose,an L-shaped frame nano-antenna(LSFNA) is designed to introduce into the biological tissue.Thus,the radiation characteristics of the LSFNA such as near and far-field intensities,directivity,and sensitivity to its gap width are studied to the optimization of the nano-antenna.The bio-heat and Maxwell equations are solved using the finite element method.To prevent damage to healthy tissues in this method,the antenna radiation must be completely controlled and performed carefully.Thus,penetration depth,special absorption rate,temperature distribution,and the fraction of tissue necrosis are analyzed in the biological tissue.That is why the design and optimization of the nano-antennas as a radiation source is important.Also,a pulsed source is used to excite the LSFNA.Furthermore,focusing and efficiency of the nano-antenna radiation on the cancer cell is tuned using an adjustable liquid crystal lens.The focus of this lens is changing under an electric field applied to its surrounding cathode.

电视跟踪镜头液晶分划板设计

介绍了一种新型的分划板的设计方法 ,该分划板是以液晶板为核心的显示器。将这种分化板置于电视跟踪镜头的主光路中 ,用以显示瞄准光标 ,可取代电视跟踪镜头的辅助光路 ,使镜头的结构得到简化。文中对液晶分化板的构成作了系统的描述 ,分析了研制中的主要技术难点 ,提出了相应的解决办法。

Adaptive multiscale microscope with fast zooming,extended working distance,and large field of view

The field-of-view(FOV),depth of field,and resolution of conventional microscopes are constrained by each other;therefore,a zoom function is required.Traditional zoom methods lose real-time performance and have limited information throughput,severely limiting their application,especially in three-dimensional dynamic imaging and large-amount or large-size sample scanning.Here,an adaptive multiscale(AMS)imaging mechanism combining the benefits of liquid lenses and multiscale imaging techniques is proposed to realize the functions of fast zooming,wide working distance(WD)range and large FOV on a self-developed AMS microscope.The design principles were revealed.Moreover,a nonuniform-distortion-correction algorithm and a composite patching algorithm were designed to improve image quality.The continuous tunable magnification range of the AMS microscope is from 9×to 18×,with the corresponding FOV diameters and resolution ranging from 2.31 to 0.98 mm and from 161 to 287 line-pairs/mm,respectively.The extended WD range is 0.8 mm and the zoom response time is 38 ms.Experiments demonstrated the advantages of the proposed microscope in pathological sample scanning,thick-sample imaging,microfluidic process monitoring,and the observation of living microorganisms.The proposed microscope is the first step towards zoom multiscale imaging technology and is expected to be applied in life sciences,medical diagnosis,and industrial detection.

一种高性能液晶透镜的设计方法

提出了一种高性能液晶透镜的设计方法。该方法结合了电极结构的设计并利用了液晶材料线性响应区。所设计的电极结构用于产生抛物线的电压分布,将驱动电压控制在液晶材料的线性响应区内可以实现抛物线的相位分布。通过该方法设计的液晶透镜,其孔径可以是任意大小,且不依赖高阻膜。所设计的电极结构简单,加工只需要一次光刻。透镜由两个低电压驱动,驱动方法简单,其焦距可通过两个驱动电压进行调节。理论上这种液晶透镜的相位分布在变焦过程中保持理想的抛物线分布,且光焦度正比于两个驱动电压的差值。实验上,通过光刻法加工了所设计的电极结构,测量了液晶材料的线性响应区,制作了液晶层厚度为50μm的液晶透镜。通过偏振干涉原理采集了干涉条纹,并从中提取了相位信息。实验结果表明,透镜的相位服从抛物线分布,且光焦度与驱动电压的差值成正比。实验结果与理论分析一致。

利用光轴可移动液晶透镜的立体图像采集系统

针对传统双目视觉系统体积大、成本高等缺点,提出了一种利用光轴可移动液晶透镜的单相机立体图像采集系统。该系统由一个固定的相机模块和一个贴有偏振片的液晶透镜构成。通过改变电压的方式移动光轴并采集图像,利用光流法获取图像视差。研究了液晶透镜光轴变化对系统整体光轴的影响,推导了视差与深度的关系。通过验证所采集的图像存在视差来说明所设计系统的可行性,并进行了近距离物体的深度获取。实验结果表明,利用液晶透镜的光轴移动功能可以使系统的整体光轴产生移动,实现立体视觉。所设计系统无需机械移动,具有结构简单紧凑和成本低廉的优点,为立体图像的采集提供了新的方法。

利用固体浸没透镜的近场光学存储研究

固体浸没透镜的近场光学存储是一种有效的超高密度光存储方法。在自建的实验装置上利用固体浸没透镜 (SIL)在偶氮聚合物液晶 (P CN)上进行近场光存储实验 ,存储点的尺寸小于 0 5 μm(激光波长为 5 32nm)。并且研究了不同聚焦深度及入射激光强度对记录效果的影响。

改进宽银幕投影显示照明系统的设计方法

照明系统是投影显示系统的重要组成部分,决定着整个系统的亮度和照明均匀性。复眼系统是一种常见的液晶投影显示系统照明结构。传统的复眼照明系统设计方法中,复眼小透镜具有与液晶板相同的长宽比,可以获得能量利用率和均匀性都比较好的照明光斑。但研究发现,利用这种方法设计宽银幕投影显示设备的复眼照明系统,会引起一定的光能损失。针对这一问题,通过对复眼系统设计理论的分析和对实际复眼照明系统的模拟,创新性地提出了在照明系统中引入柱面透镜改变复眼小透镜的长宽比的设计方法,能够有效的提高投影系统能量利用率。模拟计算结果表明,引入柱面透镜的复眼照明系统与传统方法设计的复眼系统相比,能量利用率可以提高5%到10%。

减少电润湿液体透镜变焦时间的实验研究

电润湿液体透镜是通过改变液面的形状而实现变焦的,变焦时间由透镜本身和驱动电压共同决定.为了减少变焦时间,需加快液面运动的速度,而黏滞系数较大的液体透镜其液面运动速度较慢.针对这一问题,提出了一种减少变焦时间的方法,即采用过驱动电压提高液面运动速度,然后将驱动电压降至目标电压.为验证该方法的有效性,基于近轴光线的传输理论,设计并搭建了电润湿液体透镜变焦时间的测试系统,分析了该系统的测试机理,研究了不同过驱动电压对电润湿液体透镜变焦时间的影响.结果表明,最佳情况下变焦时间由350ms减少至82ms.

眼镜光学技术的新进展

本文从光学材料、表面处理、镜片设计等方面阐述用于眼镜片的新技术,还简要介绍了液晶和电致变色器件(ECD)在眼镜光学技术中的应用。