基于EWOD的锥形管状结构液体变焦透镜

提出了一种基于介质上电润湿(EWOD)的液体变焦透镜的新结构.它由一个依次覆盖有ITO透明导电薄膜及疏水介质膜的下极板、悬在其上的一个内外壁均覆盖有疏水层的玻璃锥管以及处于两者之间的导电液滴组成.通过改变ITO与液滴之间的电压大小,透镜的曲率及位置能同时被调节,从而实现对透镜焦距的调节.实验结果表明,该器件在0～50 V电压下可实现对2 cm至无穷远处物体的聚焦.     

基于介质上电润湿的平面可变焦液体微透镜*

在现代光学技术中,可变焦微透镜被越来越广泛的使用.在提出的各种新型的可变焦微透镜技术中,基于介质上电润湿的微流体透镜由于其结构简单、功耗低、调节焦距方便等众多突出的优点而被人们所重视.本文中研制出一种基于介质上电润湿的平面微透镜结构,它不仅能控制改变焦距,还能实现透镜在平面上的横向运动.     

F-Theta Ronar 420mm透镜

埃赛力达科技有限公司旗下Qioptiq^■推出用于3D制造、焊接和半导体制造的F-Theta Ronar 420mm扫描透镜,透镜针对14mm、15mm和20mm的入射光束克径(1/e^2)进行了优化,符合最高质量标准。其大焦距适用于增材制造、半导体和金属加工行业中的各种应用。     

富士胶片发布X100专用广角转换镜头

近日,富士胶片正式发布了WCL-X100,一款为备受赞誉的Fujifilm X100数码相机量身定做的广角转换镜头。将该镜头直接加装于X100的镜头上之后,镜头组合焦距将变为原来的0.8倍,即从23mm(135等效焦距为35mm)变为19mm广角(135等效焦距为28mm)。     

《透镜然像》模拟实验课件赏析

《透镜成像》是几何光学中非常重要的内容之一。本课件适用于凸透镜和凹透镜两类透镜教学，可以改变焦距，并能用实线、虚线和带箭头的．实线三种线型画光路图，同时还能即时显示物距、像距和焦距二者之间的精确关系。课件充分利用了Flash的交互功能，所以它也是一个“以学均主”的好学具，不仅适用于高中，其中的某些功能同样适用于初中教学。     

《透镜成像》模拟实验课件赏析

《透镜成像》是几何光学中非常重要的内容之一.本课件适用于凸透镜和凹透镜两类透镜教学,可以改变焦距,并能用实线、虚线和带箭头的实线三种线型画光路图,同时还能即时显示物距、像距和焦距三者之间的精确关系.课件充分利用了Flash的交互功能,所以它也是一个"以学为主"的好学具,不仅适用于高中,其中的某些功能同样适用于初中教学.     

像素冲上400万

PDR-M81数码相机是东芝上市的第一种四百万像素相机,它使用1/1.8英寸420万像素的RGB滤光式CCD,其像素间距为31微米。此产品装配了佳能公司2.8倍光学变焦透镜,焦距从35mm到98mm。 PDR-M81还具备静态影像拍摄、影音短片摄像(重放时可同时播放声音)和录音功能。在静态影像拍摄时,     

石油管道检测中超声探头的选择及声场分析

通过分析比较不同类型超声探头的声场,选择最适合石油管道检测的超声探头。比较了2种超声探头的倾斜对检测结果影响程度。根据几何声学的原理,得出了探头在石油以及在管壁内的焦距和焦柱尺寸的计算公式。并分析了温度、透镜曲率半径和油层厚度对探头声场的影响。通过数值计算的比较结果,选取透镜曲率半径为180mm以及油层的厚度为25mm,对内径为297mm、壁厚为14mm的海底管道进行实际检测,证实了油层厚度大可以获得理想的检测效果。     

亦虚亦实的艺术焦距

焦点和焦距在介绍焦距之前,首先应知道什么是“焦点”。光线射入到相机内的平行光束,通过相机透镜的折射,结聚成的一个小光点,即称焦点。而从镜头后主点到焦点之间的距离就叫焦距。在相机参数表中“f=x”,x就是焦距。焦距越小成像角度越大,焦距越大成像角度越小。     

软质水果收获机器人

一般的果实收获机器人,在收获时机械手都要直接接触收获对象,这在不同程度上会对果实造成损伤,特别是对软质水果(如桃等)则损伤更为严重.为解决这个问题,日本三重大学开发了在收获时不直接接触水果本体,而只抓住果梗的软质水果收获机器人.机器人的视觉装置和移动部分与一般的果实收获机器人相同,其差别是在作为执行机构的机械手上.为使机械手能抓住果梗,而一般的果梗都比较短,这就要求机械手的手指要尽可能的小而且手指还要能准确地找出果梗的位置,这会使机械手变得很复杂.为此设计了带有金属环的机械手.机械手由抓持部、切断部、金属环和金属环驱动部组成(如图1所示),金属环是一个套圈,由1.5mm的不锈钢丝做成.由驱动部驱动马达带动两个圆鼓旋转,可以使套圈的直径放大或缩小.机械手与收获时的作业顺序如图2所示,首先靠视觉装置找到收获目标(水果).机械手移至目标下面,金属环直径放大再上升,从下面套住水果,待金属环升至果梗高度时停止上升,然后金属环直径开始缩小,把果梗拉至抓持部抓住,再由圆形锯刀构成的切断部把果梗切断,最后由机械手把自己收获的水     

Miniaturized variable-focus lens fabrication using liquid filling technique

This paper describes a simple method for fabricating a variable-focus lens using polydimethylsiloxane (PDMS) filling with liquid to produce a variable-focus lens. A 2-mm diameter lens was designed in this experiment, expected to reach a focal length in the range of 3 ∼ 12 mm. The theoretical value between the liquid volume and the lens contact angle at different focal lengths were simulated and measured. The pumped-in liquid volumes ranged from 200 to 1,400 μl. The contact angles ranged from 14.25° to 49.02°. Variable focal length was produced by changing the PDMS film deformation using different micro-fluidic volumes. The focal length produce in the experiment was from 4 ∼ 10 mm. The proposed method successfully fabricated a variable-focus lens. Bonding PDMS only once using no expensive instrument such as oxygen plasma was accomplished. The final objective is to insert the variable focus lens into portable optical imagery products.     

A new liquid crystal lens with axis-tunability via three sector electrodes

A novel liquid crystal (LC) lens with an on-line tunability on focus length and optical axis is proposed in this study. The designed lens has a LC layer sandwiched by two ITO glasses, one of which is patterned with three sector electrodes. With varied sets of pre-designed voltages applied to these three electrodes, the LC lens can not only render focusing effects but also tunability on the optical axis of the lens to an arbitrary axis. A vector-form equation is developed to predict the direction of axis tuning. Simulations are next conducted to predict dynamics of the LCs in the lens and also the focusing and axis-tuning properties of the lens. Important sizes and materials and fabrication process of the lens are determined and optimized based on simulation results. The designed LC lens is fabricated, and then experiments are conducted to demonstrate the performance of the designed LC lens on axis tuning. It shows that the focusing axis of the LC lens can be effectively changed by pre-calculated combinations of three voltages. It is also shown that the average movement of the focal point per applied voltage reaches 4.778?μm/V.     

Short focal length tunable liquid crystal lenticular lens array based on fringe field effect

A liquid crystal (LC) lenticular lens array based on fringe field effect is proposed. The gradient refractive index (GRIN) profile can be generated in the LC layer because of the fringe field between the strip‐shaped electrodes and the bottom electrode. The proposed LC lenticular lens array possesses ideal lens‐like phase profile and shortest focal length (1.199 mm) when the driving voltage is 5.4 V. The focal length can be tuned with millisecond response time by changing the driving voltage of the proposed LC lenticular lens array. The rise time τ_rise and decay time τ_decay of the proposed LC lenticular lens array are 162 and 94 ms, respectively.     

Electrostatic-Force-Modulated Microaspherical Lens for Optical Pickup Head

This paper proposes a novel method for the modulation and fabrication of an aspherical microlens from a photocurable polymer for use in optical pickup heads. This novel modulation method can be employed not only to dynamically control the focal length and morphology of the microlens but also to fabricate aspherical lenses after UV curing of the photosensitive polymer. Forces in two dimensions provided by electrowetting and gradient electrostatic forces are applied to shape the polymer liquid from a hemispherical shape into a parabolic or a near- conical shape. Aspherical microlenses are designed based on constant optical-path-length theory and self-aligned by surface- tension forces. For morphology modulation, 2-D voltages are applied at the lower electrodes and between the upper and lower substrates, respectively, on a SU-8 spherical liquid-polymer droplet. The voltage applied at the lower electrodes provides an electrowetting effect on the polymer droplets, thereby reducing the contact angle of the spherical droplet, resulting in a desirable droplet height/baseline ratio for a desirable focal length. The voltage applied between the upper and lower substrates pulls up the droplet mostly at its center portion to form an aspherical shape that is close to a parabolic shape or even a conical shape. As a result, the Strehl ratio of the lens can be varied from 0.0076, as with a spherical shape, to 0.8362, as with a near-parabolic shape, and the focal-spot size can be reduced from 2.302 to 0.778 mum. The proposed method has been successfully implemented and has proven suitable for optical applications in which millimeter-diameter-size lenses with numerical apertures higher than 0.66 and focus-spot resolutions better than 0.8 mum are preferred.     

Subwavelength focusing with a Mikaelian planar lens

We show that an arbitrary TE-polarized light field propagating in a Mikaelian secant (MS) planar lens can be decomposed into modes described by the Jacobi polynomials. This light field will be periodically repeated at the Talbot length and focused with a half-Talbot length period. An analytical expression for the width of the focal spot has been obtained. The MS lens allows obtaining a focal spot of width equal to the diffraction limit in the medium. The MS lens has been fabricated as a planar photonic crystal lens in a silicon film for wavelength 1.55 μm, and its focusing properties have been demonstrated by visible light (532 nm) interference fringes.     

Pneumatic dispensing of nano- to picoliter droplets of liquid metal with the StarJet method for rapid prototyping of metal microstructures

This study presents a new, simple and robust, pneumatically actuated method for the generation of liquid metal micro droplets in the nano- to picoliter range. The so-called StarJet dispenser utilizes a star-shaped nozzle geometry that stabilizes liquid plugs in its center by means of capillary forces. Single droplets of the liquid metal can be pneumatically generated by the interaction of the sheathing gas flow in the outer grooves of the nozzle and the liquid metal. For experimental validation, a print head was build consisting of silicon chips with a star-shaped nozzle geometry and a heated actuator (up to 280°C). The silicon chips are fabricated by Deep Reactive Ion Etching (DRIE). Chip designs with different star-shaped geometries were able to generate droplets with diameters in the range of the corresponding nozzle diameters. The StarJet can be operated in two modes: Either continuous droplet dispensing mode or drop on demand (DoD) mode. The continuous droplet generation mode for a nozzle with 183?μm diameter shows tear-off frequencies between 25 and 120?Hz, while droplet diameters remain constant at 210?μm for each pressure level. Metal columns were printed with a thickness of 0.5–1.0?mm and 30?mm height (aspect ratio >30), to demonstrate the directional stability of droplet ejection and its potential as a suitable tool for direct prototyping of the metal microstructures.     

基于电-声联合的液膜厚度测量方法研究

为了拓宽液膜厚度的测量范围,提出了一种联合应用电阻法与超声渡越时间法的液膜厚度测量新方法。设计了新型的电-声复合传感器,建立了用于优化传感器电极结构参数的数值模型,以灵敏度和线性度为优化目标确定了最优电极参数,通过开展液膜厚度测量实验验证了联合测量方法的有效性。研究结果表明：同轴金属电极适合于测量较薄液膜,在2.4mm~4.4mm厚度范围内的相对误差为-4.93%至5.35%;超声探头更适用于测量较厚液膜,在3.4mm~10.0mm厚度范围内的相对误差为-3.68%至2.20%。通过联合应用电阻法和超声法可以拓展两种方法各自的测量范围并且提高测量结果的可靠性。所提出的电学-声学联合测量方法具有测量范围宽、非侵入、响应快、精度和灵敏度高、安全性好等优点,能够广泛适用于工业生产和实验室研究等场合。     

An on-line optical bench tester machine for evaluating lens quality

This study is dedicated to develop an on-line automatic optical bench tester (OBT) machine for evaluating the image quality of a camera lens that is used in a lens module of a cell phone. This tester is not only suitable for conventional solid lens, but also applicable to the developing cutting-edge tunable liquid crystal lens. The testing is accomplished via a specially-designed OBT machine, which is able to automatically move the test lens based on feedback images in the optical system in the OBT to the axial position that leads to best imaging quality and also successfully measure its focus length. In the designed OBT, a commercial inspection chart is employed, along with an automatic lens-feeding machine for a quick estimate on the best possible focusing quality, which is evaluated by the well-known modulation transfer function (MTF). For actuating the feeding machine, an algorithm, assisted by the feedback MTFs, is proposed to move the test lens to the particular position that renders the best quality. In this way, the focus length—effective focal length (EFL)—of the test lens can be obtained. The proposed algorithm in fact needs much less time of actuation than a traditional tester to obtain EFL of the test lens. The designed and constructed tester is capable of measuring varied optical performance indices for the next-generation tunable lens, like liquid crystal lens.     

Liquid film thickness measurement underneath a gas slug with miniaturized sensor matrix in a microchannel

Measurement of liquid film thickness is essential for understanding the dynamics of two-phase flow in microchannels. In this work, a miniaturized sensor matrix with impedance measurement and MEMS technology to measure the thin liquid film underneath a bubble in the air–water flow in a horizontal microchannel has been developed. This miniaturized sensor matrix consists of 5 × 5 sensors where each sensor is comprised of a transmitter and a receiver electrode concentrically. The dimension and performance of the sensor electrodes were optimized with simulation results. The maximum diameter of the sensor ring is 310 µm, allowing a measurable range of liquid film thickness up to 83 µm. These sensors were distributed on the surface of a wafer with photolithography technology, covering a total length of 8 mm and a width of 2 mm. A spatial resolution of 0.5 × 2.0 mm² and a temporal resolution of 5 kHz were achieved for this sensor matrix with a measurement accuracy of 0.5 µm. A series of microchannels with different heights were used in the calibration in order to achieve the signal-to-thickness characteristics of each sensor. This delicate sensor matrix can provide detailed information on the variation of film thickness underneath gas–water slug directly, accurately and dynamically.