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.     

基于线性成像系统的光学超分辨显微术回顾

随着纳米科学技术的发展,如何打破光学衍射极限,将光学显微术的分辨本领推进到纳米尺度,已经成为光学领域的一个核心议题.在此背景下,过去的三十年间,发展了多种超分辨光学显微技术,并在生物、材料、化学领域取得了一系列令人瞩目的应用.本文以衍射理论为线索,回顾各类基于线性成像系统的超分辨光学显微技术;对以固浸物镜、结构光照明、扫描近场光学显微术、完美透镜以及超振荡透镜为代表的超分辨光学显微技术进行综述,讨论各种技术的原理,对其特点、应用与局限加以总结,并对该领域的未来发展予以展望.     

Adaptive mechanical-wetting lens actuated by ferrofluids

We report an adaptive mechanical-wetting lens actuated by ferrofluids. The ferrofluids works like a piston to pump liquids in and out from the lens chamber, which in turn reshapes the lens curvature and changes the focal length. Both positive and negative lenses are demonstrated experimentally. The ferrofluid-actuated mechanical-wetting lens exhibits some attractive features, such as high resolution, fast response time, low power consumption, simple structure and electronic control, weak gravity effect, and low cost. Its potential applications in medical imaging, surveillance, and commercial electronics are foreseeable.     

Design of 20 mm~200 mm zoom objective lens for polarization imaging system北大核心CSCD

The zoom objective lens is an important part of the polarization imaging system. At present, the zoom objective lens on the market is relatively expensive due to the use of more aspheric surfaces. In order to reduce the processing cost of the polarization imaging system zoom objective lens, a 20 mm~200 mm zoom objective lens for polarization imaging system was designed. By using positive group compensation method and Zemax to optimize the zoom system, the final system used only 7 spherical lenses to achieve good image quality. The modulation transfer function (MTF) is greater than 0.3 at 120 lp/mm, the distortion is less than 4%, and the cam curve of the system is smooth without breakpoints. The system tolerance analysis results show that the tolerance range is set as follows: the aperture tolerance of the lens surface is 2, the thickness tolerance of the lens or air center is ±0.02 mm, the inclination tolerance of the lens surface center is ±0.025°, the lens assembly and adjustment tolerance is ± 0.025 mm, and the lens refractive index deviation is 0.002. The tolerance setting conforms to the component processing and system assembly and adjustment process, which has a certain reference value to reduce the cost of polarization imaging system. © 2022 Editorial office of Journal of Applied Optics. All rights reserved.     

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．     

非球面手机屏幕放大镜的设计

为方便老年人、视力障碍者等特殊人群看清手机上的文字及图像,采用ZEMAX光学设计软件,从高折射率材料,镜片面型和类型的选择上,以及从使用双胶合镜或非球面等方面设计了几款手机屏幕放大镜.通过分析手机屏幕放大镜特点,发现用非球面镜片不仅可以改善屏幕周边的像质并可减小镜片厚度.最后,还设计了几种放大镜与手机的契合方式,以克服现有手机放大镜片的不足.     

考虑磁透镜边缘场的质子成像系统优化设计

高能质子照相系统由四极磁透镜和准直器组成,实际透镜的边缘场将影响成像系统的性能.本文将含边缘场的磁场梯度用贝尔函数近似,提出了一种含边缘场的成像系统优化方法.通过Geant 4程序模拟了能量为1.6 GeV的质子成像系统,并通过优化方法给出了考虑边缘场的优化后的系统参数.研究了考虑边缘场时的成像系统参数对准直器孔径的影响.通过对比理想成像系统和优化前后的成像系统在使用准直器时的客体通量分布,研究了边缘场对质子通过客体的通量影响.结果表明,优化后的成像系统可以减小质子通过客体后的通量误差,并且积分差值在10^–2量级时,准直器的孔径参数变化亦在10^–2量级.     

柔性变焦透镜发展现状

本文从基于力致变形(机械传动)驱动和基于电致变形(智能材料)驱动两方面分析了柔性变焦透镜(FVFL)的发展现状。通过归纳和分析发现:柔性变焦透镜均存在温度、重力对稳定性的影响。传统力致变形驱动的柔性变焦透镜变焦范围大,但响应速度慢,不易微型化设计;电致变形驱动的柔性变焦透镜响应速度快、结构紧凑。改善变焦透镜成像质量、降低驱动电压是目前柔性变焦透镜的研究热点。探索新颖的驱动方式,研究低功耗、智能化变焦系统将是柔性变焦透镜的主要发展趋势。     

An all-silicone zoom lens in an optical imaging system

An all-silicone zoom lens is fabricated. A tunable metal ringer is fettered around the side edge of the lens. A nylon rope linking a motor is tied, encircling the notch in the metal ringer. While the motor is operating, the rope can shrink or release to change the focal length of the lens. A calculation method is developed to obtain the focal length and the zoom ratio. The testing is carried out in succession. The testing values are compared with the calculated ones, and they tally with each other well. Finally, the imaging performance of the all-silicone lens is demonstrated. The all-silicone lens has potential uses in cellphone cameras, notebook cameras, micro monitor lenses, etc.     

Field confinement with aberration correction for solid immersion lens based fluorescence correlation spectroscopy

The solid immersion lens (SIL) as a tool for increasing the field confinement as well as providing optimal performance by aberration compensation in a confocal fluorescence correlation spectroscopy (FCS) system is illustrated here. Using Zernike polynomials we show that aberration compensation and the resultant pre-shaping of the incident wavefront enables near diffraction-limited performance. This is explained based on vectorial computations for high apertures in the Debye approximation. The obtained axial resolution parameters are compared with the obtained diffusion times in a SIL-FCS experiment for measurements in solutions done at the single molecule level.     

一种数码相机定焦镜头的光学系统设计

为适应市场上对结构简洁、成像品质高且生产成本低的数码相机镜头的需要,运用光学设计软件CODE V,在传统数码相机定焦镜头的基础上,结合非球面塑料透镜理论,模拟出了生产成本较低的三片式数码相机定焦镜头。该数码相机镜头结构的特点是：模块仅包括3块透镜;选择塑料镜头代替玻璃/塑料混合镜头或者全玻璃镜头,降低了系统的生产成本;系统的后焦距增大到0.8116mm,能够确保良好的远心光路性能;透镜表面完全采用非球面设计,较好地校正了球差等各种像差,使透镜具有良好的光学成像性能。     

Large aperture phase-coded diffractive lens for achromatic and 16° field-of-view imaging with high efficiency

Diffractive lenses (DLs) can realize high-resolution imaging with light weight and compact size. Conventional DLs suffer large chromatic and off-axis aberrations, which significantly limits their practical applications. Although many achromatic methods have been proposed, most of them are used for designing small aperture DLs, which have low diffraction efficiencies. In the designing of diffractive achromatic lenses, increasing the aperture and improving the diffraction efficiency have become two of the most important design issues. Here, a novel phase-coded diffractive lens (PCDL) for achromatic imaging with a large aperture and high efficiency is proposed and demonstrated experimentally, and it also possesses wide field-of-view (FOV) imaging at the same time. The phase distribution of the conventional phase-type diffractive lens (DL) is coded with a cubic function to expand both the working bandwidth and the FOV of conventional DL. The proposed phase-type DL is fabricated by using the laser direct writing of grey-scale patterns for a PCDL of a diameter of 10 mm, a focal length of 100 mm, and a cubic phase coding parameter of 30π. Experimental results show that the working bandwidth and the FOV of the PCDL respectively reach 50 nm and 16° with over 8% focusing efficiency, which are in significant contrast to the counterparts of conventional DL and in good agreement with the theoretical predictions. This work provides a novel way for implementing the achromatic, wide FOV, and high-efficiency imaging with large aperture DL.     

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% 。     

A thin lens formula of the electrostatic bi-potential lenses

A thin lens formula, whose object and image planes are measured from the lens center, is derived for electrostatic bi-potential lenses. Its approximation degree is discussed.     

准直物镜在变焦距镜头杂散光系数测试中的作用和影响分析

在对变焦距光学镜头进行杂散光系数测试的过程中,需要了解各测试环节的作用及对测量结果的影响。讨论了准直物镜使用与否对杂散光系数测量结果的影响。通过对杂散光形成机理的分析,将杂散光来源分为视场内与视场外两种,阐述不同来源杂散光的不同特点及这两种杂散光通过准直物镜后的状态。用两个参数不同的变焦距光学镜头在有无准直物镜两种情况下杂散光系数的测量结果,说明准直物镜在杂光测试中的作用。对于视场外入射光束形成的杂散光,准直物镜的使用与否对其测量结果影响巨大,而对视场内入射光束形成的杂散光影响很小,测量时可以利用准直物镜来判断光学镜头杂散光的来源。同时通过实验说明入射光线在准直物镜间的多次反射形成的杂散光约为1%,它可作为系统误差从测量结果中剔除。     

200万像素手机摄像镜头的设计

为了适用手机这一特殊领域对微型化和简单化的摄像镜头的需要,在传统球面玻璃镜片基础上结合非球面透镜理论,运用CODE V优化出一个用于可见波段且生产成本低廉的三镜片定焦摄像镜头系统。该镜头总长度小于5mm,并且有着很好的成像效果。为了结构紧凑并且能最大限度地降低生产成本,在结构设计中采用球面的玻璃镜片和非球面的塑料镜片,镜头的适应像素尺寸是2.52μm×2.52μm,相应的尼奎斯特频率是196条/mm,相关的调制传输函数值在尼奎斯特频率的1/2时达到40%,所成像面的球差控制在-0.05mm～0.05mm之内,最大畸变小于0.17%。该镜头可满足手机摄像镜头200万像素的要求。     

高变倍比数码变焦镜头设计

为提高变焦距系统的工作性能,使其在大视场时仍具有良好的像质,且系统结构简单,易于机械设计、加工及装调,在设计中引入了传统球面光学设计与非球面相结合的设计思想。选择4个焦距位置进行设计计算,用光学设计软件ZEMAX上机调试,设计了焦距为6.9mm～91.6mm,视场5°～60°的变焦系统,整个系统由4组12片透镜组成,其中包括3个非球面,系统具有变倍比高、视场大等特点。设计结果表明：在设计中采用非球面可使系统结构紧凑,系统成像质量得到提高。     

Dispersion effect in optical microscopy systems with a supersphere solid immersion lens

This paper studies the dispersion effect of the supersphere solid immersion lens (SIL) on a near field optical microscopy system by using the vector diffraction theory. Results show that when a real non-monochromatic beam illuminates a supersphere SIL microscopy, the dispersion effect of the SIL has an important influence on the image quality. As the wavelength bandwidth of the non-monochromatic beam increases, the size of the focused spot increases and its intensity decreases in near-field microscopy systems with a supersphere SIL.     

用两区π-相位滤波器改善超半球形固体浸没透镜显微系统的成像特性

利用矢量衍射理论分析了π-相位滤波器在超半球形固体浸没透镜显微系统中的超分辨特性.结果显示,光斑的增益、Strehl率和边瓣强度随相位区域边界呈现出同步的、只一个周期的振荡性变化.从辐射场和速逝场的角度解释了这种变化的原因.对于近场显微,速逝场起决定性作用.π-相位滤波器的相位区域边界角大于临界角时,才能产生较大的超分辨作用.滤波器边界参量等于0.743（对应的角度大于临界角）的π-相位滤波器,可以使系统分辨率提高16%.     

CCD摄像机大视场光学镜头的设计

为提高CCD摄像机的成像质量，同时使镜头结构紧凑、小型化，在大视场光学镜头的设计中，引入标准二次曲面和偶次非球面。根据初级像差理论，分析了非球面的位置、初始结构参数的求解规律。通过理论计算和ZEMAX光学设计软件的优化，给出工作波长为0.4～0.7μm、全视场角为80°，相对孔径为1∶1.5的镜头设计实例。该镜头由7块镜片组成，包括一个标准二次曲面和两个8次方非球面；在40lp/mm空间频率处的MTF值超过0.85，全视场畸变小于3％，像质优良