二元变焦内窥镜光学系统设计

根据高斯光学原理,以液体透镜为核心元件,研究了无移动镜组变焦系统的设计方法。从医用内窥镜的使用要求出发,设计了一种二元变焦内窥镜系统。该系统可通过气压或液压控制液体透镜表面曲率变化,实现1.5倍变倍比,在1.8 mm和2.7 mm焦距下都获得了良好的成像质量。     

大倍率红外连续变焦系统双电机控制技术研究

采用双电机联动控制变倍组与补偿组的变焦方案替代传统的曲线套筒,实现了采用全透射式结构型式,相对口径为1/4,焦距变化范围为342.76 mm~13.15 mm连续变焦光学镜头的机械补偿式变焦。将变倍组设计成步进模式,作匀速运动,补偿组设计成位置跟踪模式,按凸轮曲线作变速运动,采用双电机全数字伺服控制凸轮（CAM）算法,将光学设计计算的变倍镜和补偿镜位置对应关系转变为对应的脉冲数输入到CAM表中,从而确定2个不同运动速度轴之间的位置对应关系。试验结果表明:双电机控制的变倍组和补偿组位置分辨率达到0.18 m,光轴一致性水平方向达到1.9,垂直方向达到1.3。     

Chromatic aberrations of thin refractive variable-focus lens

We present an approach to an analysis of the third order chromatic aberrations of thin refractive fluid lenses with a variable focal length. A detailed theoretical analysis is performed for a simple fluidic variable-focus lens and formulas are derived for an optical design of such lenses. Aberration coefficients of the third order of the variable-focus lens can be completely characterized by three parameters which depend only on refractive indices of fluids forming the variable-focus lens. Formulas were derived for the change of the third-order aberration coefficients with the wavelength. Calculations are provided for Varioptic lens Arctic-416.     

Integrated fluidic adaptive zoom lens

An integrated fluidic adaptive zoom lens is demonstrated for what is believed to be the first time. A zoom lens was fabricated using an UV lithographic-galvanic-like process involving soft lithography and wafer bonding. The zooming capability of such a lens was achieved by varying the focal length instead of the distance between the lenses. A zoom ratio of greater than 2 was obtained for devices that are 8 mm thick and have a 20-mm lens diameter. Including the 30-mm image distance, the total physical length of the fluidic zoom lens was less than 43 mm. More-compact systems with a higher zoom ratio can be obtained by reduction of the aperture size.     

Focal length measurement of a varifocal liquid lens with capacitance detection

This paper reports on a detailed deformation model of varifocal liquid lenses fabricated by Parylene-on-liquid-deposition (POLD), which can be applied to measure and adjust the focal length of such lenses without using extra sensors or sensing mechanisms. The lens was fabricated by encapsulating a liquid between a transparent electrode and a polymer film that was covered with a metal electrode. When voltage is applied to the two electrodes, the lens deforms due to the electrostatic force, and its focal length and the capacitance between the two electrodes change simultaneously. This characteristic enables the focal length of the lens to be adjusted and detected by measuring the capacitance change. The focal length of the fabricated varifocal liquid lens changed from 153.6 to 82.6 mm by applying 150-V. The focal length change of the liquid lens was calculated from the change in its capacitance. Finally, to confirm the efficiency of this varifocal liquid lens, we fabricated a confocal distance sensor using the lens for laser scanning and demonstrated that this system can be used to measure distances of 94–140 mm with an average error of 0.83 mm and a standard deviation of 0.77 mm.     

基于电湿效应的双液体透镜

介绍了一种新型的、基于电湿效应的双液体透镜的发展历史、结构原理,通过改变外加电压的大小以调节透镜的焦距,从而达到无机械运动变焦的目的.推导并分析了两种液体透镜模型的焦距与外加电压的关系.     

液体透镜的诞生和发展

本文介绍当今世界最先进的透镜成像系统——液体变焦透镜的诞生和发展.首先是哥伦比亚大学的反射式旋转液体透镜,可用作天文望远镜;透射式液体透镜从加州大学圣地亚哥分校的压力透镜,到Lucent公司的纯电力控制的液体—空气界面的透镜,再到Philips公司的方便操作的封闭式液—液界面透镜,最后到法国VariOptic公司的能自动调节光轴的改进型透镜,其中着重介绍了VariOptic的液体透镜.     

Design and fabrication of fluid controlled dynamic optical lens system

A novel small fluid controlled optical lens system that is capable of displaying dynamic variation of its focal length and field-of-view (FOV) is designed and fabricated. In this active lens system, appropriate volume of the optical fluid can be pumped into or out of the lens chamber to provide double-convex (DCX) or double-concave (DCV) lens effect. Simple optical imaging experiments were performed using different sets of glass lenses with fixed focal lengths to determine the optimum lens configuration required for designing a dynamic optical lens system. The experimental results obtained from the glass lenses demonstrate that a combination of a single DCX lens with three DCV lenses provides a wider FOV. The flexible membranes for fluid controlled lenses were fabricated using polydimethylsiloxane polymer material, which has good optical transparency and elasticity. A simple fluid injection system is used to vary the radius of curvature of the lenses, and thereby to change the focal length. A dynamic optical lens system with a combination of one DCX and multiple variable focal length DCV lenses as designed here can image an object with a wide range of focal length and FOV. With this fluid controlled optical system, the FOV and focal length could be continuously varied and a maximum FOV of 118.3° could be achieved. The smallest f-number (f_/#) for this fluid controlled single lens system was found to be 1.3, which corresponds to the numerical aperture value of 0.35.     

基于介质上电润湿的微流体变焦透镜的研究进展

近年来,微流体变焦透镜的研究已展示出其在光学系统中的应用前景,其中基于介质上电润湿(Electrowet-ting on dielectric,EWOD)的微流体变焦透镜只需改变外加电压便能快速调节透镜焦距,并且具有尺寸小、结构灵活、功耗低、焦距调节范围广等许多突出优点而日益受到注目。在介绍EWOD机理的基础上,综述了目前基于EWOD的微流体变焦透镜的研究进展。     

紧凑型8～12 μm波段折/衍混合双位置两档变焦光学系统设计

设计了工作于8～12 μm波段的折/衍混合双位置两档变焦光学系统.该系统变焦过程中相对孔径保持不变,F/#为1.7,系统变倍比为3.75∶1.大视场角为19.2°,有效焦距33 mm,用于在大范围内搜索目标；小视场角为5.1°,有效焦距125 mm,用于对目标进行具体分析.系统采用锗和硒化锌两种材料,为四片镜结构,仅通过两片透镜的轴向移动便可完成两个视场的切换.系统中引入二元面和高次非球面,使系统结构简化,并极大地提高了成像质量.该系统适用于像元尺寸20 μm的非致冷式面阵探测器,可广泛应用于军事扫描成像和红外前视系统中.     

Refraction and ultra‐small‐angle scattering of X‐rays in a single‐crystal diamond compound refractive lens

In this work a double‐crystal setup is employed to study compound refractive lenses made of single‐crystal diamond. The point spread function of the lens is calculated taking into account the lens transmission, the wavefront aberrations, and the ultra‐small‐angle broadening of the X‐ray beam. It is shown that, similarly to the wavefront aberrations, the ultra‐small‐angle scattering effects can significantly reduce the intensity gain and increase the focal spot size. The suggested approach can be particularly useful for the characterization of refractive X‐ray lenses composed of many tens of unit lenses.     

Achromatic doublets using group indices of refraction

One main function of short pulses is to concentrate energy in time and space [1]. The use of refractive lenses allows us to concentrate energy in a small volume of focusing around the focal point of the lens. When using refractive lenses, there are three effects that affect the concentration of energy around the focal point of the lens. These are the group velocity dispersion (GVD), the propagation time difference (PTD), and the aberrations of the lens. In this paper, we study lenses which are diffraction limited so that the monochromatic aberrations are negligible; the group velocity dispersion and the propagation time difference are the main effects affecting the spreading of the pulse at the focus. We will show that for 100-fs pulses the spatial spreading is larger than the temporal spreading of the pulse. It is already known that the effect of spatial spreading of the pulse due to PTD can be reduced by using achromatic optics. We use the theory proposed by A. Vaughan to analyze simple lenses and normal achromatic doublets, where normal means doublets that we can buy from catalogs. We then use the Vaughan theory to design achromatic doublets in phase and group, which produce no spatial spreading of the pulse, i.e., PTD = 0, when the doublet is designed for the carrier of the pulse. We compare these phase and group achromatic doublets with normal achromatic doublets. Finally, we show that apochromatic optics can give a much better correction of PTD than using normal achromatic doublets.     

液滴透镜在电场中的变形研究

利用电场作用操控液滴面形获得非球面液滴透镜,并实时检测其光学性能,利用紫外光固化技术使液滴透镜固化得到固体非球面透镜.实验测量了液滴透镜的面形并经过图像处理提取面形轮廓,经多项式拟合得出液滴透镜的面形表达式.比较了不同强度电场作用下的液滴透镜面形,计算了主曲率随电场的变化规律,讨论了液滴透镜在电场中的变形机制|根据透镜面形表达式,采用光线追迹法得出了液滴透镜的焦距随电场的变化规律,结合ZEMAX软件计算了3 550 V时液滴透镜的最大波像差为0.32个波长,Strehl Ratio为0.74,及光学传递函数等参数,计算了所制作的非球面透镜的像差,为低像差非球面透镜的研制提供了依据.     

液体可变焦折衍混合光学系统

提出了一种液体可变焦折衍混合光学系统，该系统将传统的折射透镜的其中一面设计成二元面，通过改变折射系统的曲率半径来实现对整个光学系统的焦距的调节．这种液体可变焦折衍混合光学系统的主要优点是能够消除色差．经实验证明该光学系统焦距和折射系统的曲率半径呈线性变化关系并且在变焦的同时很好的解决了色差问题．     

薄透镜组的焦点位于组合透镜两侧时应满足的条件

透镜组的焦距和焦点位置是透镜组的主要参数,本文通过对两薄透镜多种不同组合的讨论,总结出使组合透镜的焦点处在透镜组两侧需满足的条件．     

On the use of lenses to focus few-cycle pulses with controlled carrier–envelope phase

From a model of focusing with lenses that includes the effects of the lens variable thickness, material dispersion, aperture, spherical and chromatic aberrations, we characterize the conditions under which a lens can focus to few-cycle, transform-limited pulses propagating without distortion along the focal region. A lens also allows to control the carrier?Cenvelope phase shift along the focus. The carrier?Cenvelope phase shift is drastically reduced by focusing with specific focal lengths and input spot sizes, which are of the same order as those typically used in experiments involving focusing for phase-sensitive, light-matter interactions.     

Measuring optical properties of an eye lens using magnetic resonance imaging

We compare the focal lengths of porcine lenses measured optically and by using a novel MRI technique. The geometric properties of the lenses were also measured and compared. The MRI technique exploits the dependence of both the lens refractive index and relaxation rates on the local protein concentration. By measuring the refractive index and corresponding values of R2 (=1/T2) for samples of lens homogenates with different protein concentrations, the dependence of refractive index on R2 was determined empirically. R2 maps, constructed from monoexponential fits to multiecho images of a slice through the lens containing the optical axis, were converted to refractive index maps using this relationship. A simulated ray trace through the refractive index map provided an estimate of lens focal length that was compared to a direct optical measurement of focal length using a laser ray-tracing method. It was found that the mean focal lengths estimated from the two techniques agreed within experimental uncertainty. The refractive index profile along the optical axis was found to be well described by a simple function of the form n=n0 + n1 x ra where r is the (normalized) lens radius.     

一款超薄800万像素手机镜头的设计

为了满足市场对超薄手机镜头的要求,运用光学软件CODEV,结合非球面理论,设计一款新的超薄800万像素手机镜头。该镜头由4片非球面塑料镜片,1片滤光镜片和1片保护玻璃组成,其中第1片透镜是正透镜,第2片镜片是负透镜,第3片镜片是正透镜,第4片镜片是负透镜,且光阑位于第1片透镜的前面。镜头光圈值F为2.4,视场角2为65.5,焦距为3.731 5 mm,后焦距0.31 mm,镜头总长度为4.6 mm,在最高频率1/2处大多数视场的MTF值均大于0.5,畸变小于2% 。     

Modified nodal point method for the measurement of the large focal length of lenses

Some modifications have been suggested to the nodal slide and microscope method to suit the focal length measurement of large focal length lenses. In this procedure, the experimental set-up has to be accommodated on the two usual optical benches in line, and the position of the nodal point of the lens under test is easily located by introducing an extra lens of comparatively shorter focal length between the test lens and microscope. The results of the measurement of ‘f’ for a few lenses, and the experimental parameters, are presented.     

基于平行光管法的薄凸透镜焦距测量

薄凸透镜是光学仪器中最重要、最基本的元件,在天文、军事、医学等众多领域发挥着重要作用。焦距是薄透镜、反射镜等光学系统最重要的特性参量,因而准确测量薄透镜的焦距则显得尤为重要。实验室测量薄凸透镜焦距的方法有物距像距法、自准直法、光电法、平行光管法等。由于采用前3种方法测量透镜焦距的精度偏低,针对该问题,提出利用平行光管法测量薄凸透镜的焦距,并对实验误差作简单分析。实验结果表明,该方法可以高精度地测量薄凸透镜焦距,相对误差仅为0.138%。因此,采用平行光管法的薄凸透镜焦距测量方法是有效可行的。