共查询到20条相似文献,搜索用时 718 毫秒
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Traceable radius of curvature measurements are critical for precision optics manufacturing. An optical bench measurement is repeatable and is the preferred method for low-uncertainty applications. With an optical bench, the displacement of the optic is measured as it is moved between the cat's eye and the confocal positions, each identified using a figure measuring interferometer. The translated distance is nominally the radius of curvature; however, errors in the motion of the stage add a bias to the measurement, even if the error motions are zero on average. Estimating the bias and resulting measurement uncertainty is challenging. We have developed a new mathematical definition of the radius measurand that intrinsically corrects for error motion biases and also provides a means of representing other terms such as figure error-correction, wave-front aberration biases, displacement gauge calibration and their uncertainties. With this formalism, it is no long necessary to design a high-quality radius bench to carry out a precision measurement; rather a lower quality is adequate, provided that error motions are repeatable and characterized and error motion measurement uncertainties are estimated. 相似文献
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A new laser differential confocal lens refractive index measurement is proposed, which uses the absolute zero of the differential confocal axial intensity curve to precisely identify the positions of the objective when the measurement pencil is focused on the vertex of the test lens and the reflector with or without the test lens in the measurement light-path, and then uses aberration compensation and ray tracing facet iterative calculation to obtain the refractive index of the test lens, thereby achieving the high-precision noncontact measurement of lens refractive index. The theoretical analyses and preliminary experiments indicate that the accuracy of the approach can reach about 2.5×10(-4). 相似文献
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Application of the astigmatic method to the thickness measurement of glass substrates 总被引:1,自引:0,他引:1
We developed a high accuracy thickness measurement system for glass substrates based on the optical design of the astigmatic method. The astigmatic optical system includes a laser diode, a cylindrical lens, a convex lens, and a quadrant detector. This method measures the astigmatic focusing error signal induced from the measured glass placed in the astigmatic optical system. The astigmatic focusing error signal is converted into the thickness of the glass substrate. The proposed glass thickness measurement system is verified by using a coordinate measuring machine (CMM). The accuracy of the proposed system is 0.2 microm, with a standard deviation of 0.7 microm within the thickness measuring range of 1.2 mm. 相似文献
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基于单缝衍射原理的圆度误差测量方法 总被引:1,自引:0,他引:1
提出了一种全新的圆度误差光学自动测量方法.新方法基于单缝衍射原理,利用工件的圆度误差来改变衍射单缝的宽度,进而改变衍射条纹的间距.在测量单缝衍射中央明纹的宽度时,提出了用最小二乘法对测量到的衍射图像的光强分布进行二次曲线拟合,并由拟合得到的数学表达式,确定衍射暗条纹的精确位置.由导出的工件圆度误差与单缝衍射中央明纹宽度之间的关系,用最小二乘法对工件的圆度误差进行了评定.测量结果表明,新的圆度误差测量方法是可行的,圆度误差的相对不确定度小于1.4%,并且测量系统具有操作方便、精度高的优点,新方法也可应用于锥角、直线度误差等其它几何量的精密测量中. 相似文献
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研制了可对一维高温温度场进行测量的扫描式高温计.该扫描式高温计分为旋转扫描式光学系统、比色高温计和上位机三个部分.在分析温度场测量要求的基础上,推导了比色光学高温计的测量原理,建立了数学模型.基于光的反射理论,研究了旋转扫描式光学系统与一维温度场之间的运动关系.利用光学光纤将光学探头接收的光信号进行远距离传输,增加了测量的便利性和整套装置对测量环境的适应能力,专用的微型工控及控制系统提高了这套装置独立工作及与其他设备进行协调合作的能力.对比色高温计的波长函数和测量精度进行了标定,校验结果表明在800℃~3500℃范围内的测量精度为1%.最后,利用扫描式高温计对棒状碳/碳试样的轴向温度场进行了测量,通过几个固定点温度对一维温度场的测量精度进行了校验,最大测量误差为3.09%. 相似文献
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High-accuracy measurement of 240-m distance in an optical tunnel by use of a compact femtosecond laser 总被引:1,自引:0,他引:1
A high-accuracy optical distance meter with a mode-locked femtosecond laser is proposed for distance measurements in a 310-m-long optical tunnel. We measured the phase shift of the optical beat component between longitudinal modes of a mode-locked laser. A high resolution of 50 mum at 240-m distance was obtained without cyclic error correction. The group refractive index of air is automatically extracted to an accuracy of 6 parts per million (ppm) by two-color measurement with the pulses of fundamental and second-harmonic wavelengths. Finally, an absolute mechanical distance of 240 m was obtained to within 8-ppm accuracy by use of a series of beat frequencies with the advantage of a wide range of intermode frequency, together with the results of the two-color measurement. 相似文献
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为了有效开展长距离光电测距类仪器的室内检定工作,在50m高精度导轨上利用1组平面反射镜进行光路折叠,搭建了100m室内基线场。对基线系统的测量误差进行了分析,考虑各项误差的调整精度,将误差分析结果应用到实际光路调整过程中,分析得到对基线长度影响更显著的误差量,并对其进行了控制和调整,提高测量光路的平行性调整精度,最后选择双频激光干涉仪作为长度基准开展验证实验。实验结果表明:通过光路折叠方法可以实现2倍光程倍增,基线系统的精度较高,可进行连续测量,有效地解决了室内基线建立过程中所存在的检测效率低、可重复性差等技术问题。 相似文献
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便携式激光表面粗糙度测量仪 总被引:3,自引:0,他引:3
介绍了一种基于光散射原理的便携式激光表面粗糙度测量仪。它采用半导体激光器光源,以元心光路结构接收、处理经粗糙表面调制的散射光带,成功地解决了粗糙度测量精度高低与测量范围大小相矛盾的问题。仪器结构简单、操作方便、测量效率高,精度能满足生产实际的需要。 相似文献
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A novel, precise, three-dimensional shape measurement method using scanning electron microscopy (SEM) and Moiré topography has been proposed. The possibility for measurement of wavelength order using this method is discussed based on results of experiments to confirm the principle. In these experiments, a high-resolution method based on the new measurement method is proposed, employing fringe scanning technology for the shadow Moiré. The optical system is constructed with a SEM using backscattering electrons, a grating holder that can shift the position of the grating, and a grating having a pitch of 120?µm. Measured results using a bearing ball as a sample show that high resolution measurements of around one micrometre can be performed using the fringe scanning method and the new measurement arrangement. An error analysis of the method is performed to enable improvement of the measuring accuracy. 相似文献
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A novel transmitted-light differential interference contrast (DIC) system is used for nondestructive measurement of the refractive-index profile (RIP) of an optical fiber. By means of this system the phase of a measured light beam can be modulated with an analyzer, and the phase distribution of a fiber is obtained by calculation of the various interference patterns. The measurement theory and structure and some typical applications of this system are demonstrated. The results of measuring RIPs in graded-index fiber are presented. Both the experimental results and theoretical analysis show that the system takes the advantage of high index resolution and of sufficient measurement accuracy for measuring the refractive index of the optical fiber. The system has strong ability to overcome environmental disturbance because of its common-path design. Moreover, one can use the system to measure the RIP along the fiber axis and acquire an image of the three-dimensional RIP of the fiber. 相似文献
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通过对环规测量数据的分析,发现星形探针在使用中存在着由于各个探针动态半径不同而造成的测量误差。在论述误差产生原因的基础上,提出了一种间接测量方法"测点计算法",来消除星形探针带来的误差,进而提高测量精度。 相似文献
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We investigated a high-precision optical method for measuring the thickness of biological samples regardless of their transparency. The method is based on the precise measurement of optical path length difference of the end surfaces of objects, using a dual-arm axial-scanning low-coherence interferometer. This removes any consideration of the shape, thickness, or transparency of testing objects when performing the measurement. Scanning the reference simplifies the measurement setup, resulting in unambiguous measurement. Using a 1310?nm wavelength superluminescent diode, with a 65?nm bandwidth, the measurement accuracy was as high as 11.6?μm. We tested the method by measuring the thickness of both transparent samples and nontransparent soft biological tissues. 相似文献
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We show an interferometric method for measuring phase change with known uncertainty. Because this measurement uses the backreflection from a sample, the height is intrinsically removed, and only the phase change is measured. The uncertainty in the phase change measurement is +/-3.8 degrees and is dominated by the background subtraction method. We also investigate the effect of the phase change on the interferometric radius measurement. The theoretical worst-case error in the interferometric radius measurement due to the phase change is 30 nm. 相似文献