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An innovative nondestructive technique for measuring the refractive index of a simple lens is described. The proposed method is superior to existing ones because the focusing error and the spherical aberrations are reduced. Apart from this, the strength parameters (i.e., r1 and r2) of a lens are not required at all since the derived lens-index formula is independent of the lens's physical parameters. The shearing interferometric technique is a sensitive aid for detecting the focal plane of the test lens. A modified criterion for determining the focal length has been used. In this case two miscible liquids or compounds are not necessary. The well-known liquid immersion method is the particular case of this technique. The Murty shearing interferometer has been used as an optical device to observe the defocusing defect in the form of fringes. The amount of defocusing is easily calculated. An equation for this error has been theoretically deduced and experimentally verified. The technique described is quick to perform and easy in handling. The various effects due to the lens's aperture and aberrations, thickness of the glass cell, liquid column, etc. are also discussed. For N liquids, there are N(N - 1)/2 ways of calculating the lens's index. Owing to its nature this is termed the nondestructive nonmiscible-liquid immersion technique for index measurement of a lens. 相似文献
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远距离高精度多普勒位移测量 总被引:2,自引:1,他引:2
通过泛函、激光散斑理论和随机过程各态遍历的研究,导出激光多普勒信号强度与聚焦光斑直径、接收透镜通光口径、光电接收器响应等参数间的关系,在此基础上设计出一种适用于远距离处面内位移测量的光路。此光路将高斯光束束腰聚焦在被测体上,实现最小聚焦光斑和平面波叠加,此外采用大口径透镜接收散射光,用响应度高的光电接收器转换光电信号等措施获得高强度高信噪比的测量信号。将此光路用于 100m 处面内位移(49.70mm)测量,其精度可达 2%。此设计方法能用于振动或地震波的高精度检测。 相似文献
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A laser differential confocal radius measurement system with high measurement accuracy is developed for optical manufacturing and metrology. The system uses the zero-crossing point of the differential confocal intensity curve to precisely identify the cat's-eye and confocal positions and uses an interferometer to measure the distance between these two positions, thereby achieving a high-precision measurement for the radius of curvature. The coaxial measuring optical path reduces the Abbe error, and the air-bearing slider reduces the motion error. The error analysis indicates the theoretical accuracy of the system is up to 2?ppm, and the experiment shows that the system has high focusing sensitivity and is little affected by environmental fluctuations; the measuring repeatability is between 4 and 12?ppm. 相似文献
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本文对GRIN透镜的精确光线追迹公式作了推导,介绍了轴位移法对透镜折射率分布的测量方法及相应的数据处理,并对测量误差进行了分析和计算,从而对测定GRIN透镜折射率分布提供了一种精确而且实用的方法。 相似文献
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The methodology of synthesizing a model for a diffraction laser-optical system for measuring the thickness of large diameter
lenses within the framework of engineer-graph procedures for the design, manufacture, and study of a laser-electronic Fourier
thickness gage is developed. Nine stages are identified for model synthesis based on successive-parallel sorting of models
when considering statement of the problem in designing a laser-electronic Fourier thickness gage. The task of creating a fundamentally
new method and provisions for measuring lens thickness is solved by means of an automatic diffraction-geometric-optical method
for recording the space-frequency spectrum of the measuring aperture. Schematic analysis is performed and a functional optical
scheme is constructed for a two-channel diffraction laser-optical system for measuring lens thickness. A measurement procedure
is developed and the Fourier thickness gage developed is studied by experiment.
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Translated from Izmeritel'naya Tekhnika, No. 10, pp. 30–35, October, 2005. 相似文献
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为了提高镜片焦度测量的精度和效率,针对镜片测量时因手动调节而存在镜片偏心等问题,提出了一种结合哈特曼检测法、机器视觉技术以及步进电机控制系统来测量镜片的技术方案.基于此方案设计并制作了一种镜片全自动测量系统.系统实现了对哈特曼光阑下多光斑实时大小和位置的分析,利用搭建的机械模块自动校准镜片位置并测量镜片.用-15m-1... 相似文献
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一种数字投影式顶焦度测量仪 总被引:1,自引:0,他引:1
提出一种数字投影式顶焦度测量的技术方案。根据此方案设计的焦度测量仪,通过精密机械传动,嵌入以单片微型计算机为核心的硬件控制系统和软件处理系统,对眼镜镜片球镜顶焦度、球柱镜顶焦度及轴位角等进行了测量。它通过光学投影的方式进行对焦,测量活动标尺的平动量和转动量来计算相应参数,并利用液晶 LCD 显示结果。采用一种动态基准存储技术,通过预先存储的动态基准来计算顶焦度,可以有效消除系统误差,提高测量精度。对产品样机的试验结果表明,顶焦度的测量精度达到±0.03D。 相似文献
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针对密集波分复用(DWDM)技术中所使用的梳状滤波器,对固体腔研磨厚度指标要求极高△v=200 GHz,△d≤13.37 nm,本文提出运用法布里-珀罗干涉理论(Fabry-Perot),研究设计了一种针对固体腔厚度的现场检测方法.该方法根据被测元件等效为系统干涉腔的间接测量方法,以通过被测元件后的法珀相邻能量极值特性,作为检测厚度合格的判定依据,实现了对超窄带梳状滤波器组成元件--未镀膜层固体腔(SiO_2)的高精度厚度检测.实验结果表明,该测量方法适用于对透光介质的厚度检测. 相似文献
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A method of measuring the parameters of amplitude-modulated signals that is optimum with respect to interference protection and gives a higher measurement accuracy with a shorter measurement time which may be less than the period of the envelope is proposed and investigated. Algorithms for processing the input signal in analog and digital form are obtained, an estimate of the error is given and two versions of a measuring system are proposed.Translated from Izmeritel'naya Tekhnika, No. 1, pp. 61–64, January, 1995. 相似文献
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An optical system that can measure vibrations and displacements is developed by using the oblique ray method. By employing a single convex lens that plays both roles of sending and receiving the beams that are reflected by the target surface, the optical measurement system became compact and reliable. A position-sensitive detector is used to measure the position change of the beam spot on the target surface. The resolution of the optical system can be controlled by changing the optical magnitude of the objective lens and is designed to be less than 0.1 microm for the developed system. 相似文献
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An experimental comparison of the ring-lens and the astigmatic techniques of generating a focus-error signal (FES) in optical disk systems reveals that the ring lens generates a FES curve over two times steeper than that produced by the astigmat. Partly because of this large slope and partly because of its diffraction-limited behavior, the ring-lens scheme exhibits superior performance characteristics. In particular, the undesirable signal known as feedthrough (induced on the FES by track crossings during the seek operation) is substantially lower than that observed with the astigmatic method. The ring lens is easy to align and has reasonable tolerance for positioning errors. 相似文献
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提出一种具有滚转角测量自动校正功能的五自由度运动误差测量系统,解决了平行双光束法在测量滚转角误差时受光束平行度影响较大的问题。介绍了平行双光束法测量五自由度运动误差的原理,建立了关于双光束平行度误差与滚转角测量误差间的模型,提出了基于双自准直单元的双光束平行度误差测量方法。实验结果表明:双光束之间存在15.4″的平行度误差时,可以将滚转角测量误差的残差由44″减小到2.7″。该校正方法有效提高了双光束测量滚转角的准确性,可用于直线导轨运动误差的在线监测。 相似文献
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We present a simple method for measuring the effective focal length without determining the location of principle plane of the lens. The method is based on the measurement of confocal backreflection axial responses from the front and back surfaces of a reference plate with known refractive index and thickness. We proved the concept by measuring the effective focal lengths of thin singlet lenses and complex microscope objectives. The theoretical limit of measurement precision varies depending on the numerical aperture of the lens. This method can provide an alternative focal length measurement method for complex lenses or lenses that are permanently attached to other structures. Measurement errors were analyzed theoretically and improvements in measurement accuracy were discussed. 相似文献