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为了抑制激光在线测厚时入射角波动引起的误差,根据几何光学分析了激光透射式和反射式测厚原理,发现激光在特定入射角附近波动时,两种方式的测厚误差一正一负,具有互补性,在此基础上提出基于透射和反射同时测量的互补式测厚方法,该方法可将误差限定在透射式和反射式测量误差之间,抑制在线测厚误差.对于有机玻璃平板,理论计算表明,当激光入射角在67.013°±4°波动时,相对误差绝对值在1%以内,误差抑制率均值大于90%;当入射角为61.536°时,误差抑制率为100%.利用线结构激光器和两个线阵CCD相机搭建互补式测厚实验系统,测量了标称厚度为1~5mm的有机玻璃平板,与透射式和反射式测厚结果进行对照,除厚度为1mm的玻璃外,互补式测厚误差被限制在透射式和反射式之间,最大误差抑制率达61%.实验结果表明,该互补式方法有效抑制了误差,提高了在线厚度测量准确度,解决了在线测量不可重复性导致的无法通过均值法减小误差的问题. 相似文献
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提出了使用用迈克尔逊干涉仪,改变光源入射方式及观测方式以获得稳定、清晰等厚干涉现象的方法.探究了在光路中插入的被测透明介质如何对等厚干涉条纹产生影响,并导出了被测介质厚度、折射率及旋转角度与等厚干涉条纹移动量之间的关系.实现对透明介质厚度、折射率进行简练、快速的同时测量. 相似文献
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对薄膜测厚系统进行了详尽剖析,从整体上论述了膜厚测量系统,研究了测厚系统中薄膜测厚仪的关键硬件电路,对薄膜测厚仪的软件流程进行了离散设计。以AVR单片机为核心处理器进行了数据采集和处理,设计并生产出了在线式光学薄膜厚度测量与监控系统。通过与实际膜厚进行对比实验,验证了薄膜测厚系统具有高精度、高稳定性和高可靠性,可应用于实际工业生产。 相似文献
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报告了我国开展射线检测原油管道垢厚的研究进展. 介绍了γ射线透射检测垢厚的基本原理、 模拟实验装置及主要研究成果. 研究表明, 研制透射型测垢仪是可行的. 另外, 还给出了南京大学关于表面型中子测垢仪和γ射线测垢仪的初步预研结果. 相似文献
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Combining Cubic Spline Interpolation and Fast Fourier Transform to Extend Measuring Range of Reflectometry 下载免费PDF全文
The reflectometry is a common method used to measure the thickness of thin films. Using a conventional method,its measurable range is limited due to the low resolution of the current spectrometer embedded in the reflectometer.We present a simple method, using cubic spline interpolation to resample the spectrum with a high resolution,to extend the measurable transparent film thickness. A large measuring range up to 385 m in optical thickness is achieved with the commonly used system. The numerical calculation and experimental results demonstrate that using the FFT method combined with cubic spline interpolation resampling in reflectrometry, a simple,easy-to-operate, economic measuring system can be achieved with high measuring accuracy and replicability. 相似文献
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Kazuhiko Ishikawa Hitomi Yamano Katsuhiko Asada Koichi Iwata Masahiro Ueda 《Optics and Lasers in Engineering》2004,41(5):731
An ingenious optical method was developed for measuring the thickness of a coating directly and in real time at a measuring frequency of a few tens of Hz. The basic optical arrangement is very simple, and consists of a semiconductor laser, two cylindrical lenses, and a silicon photodiode array or CCD camera. The range of measurable thickness is roughly between λ and 100λ, where λ is a wavelength of the laser light, and its measuring error is a few percent. The previously developed method for measuring the thin film in air, which can be analyzed theoretically, can also be applied for estimating the thickness of a coating on the substratum within an error of 2%. 相似文献
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A spectroscopic method to determine thickness of quartz wave plate is presented. The method is based on chromatic polarization interferometry. With the polarization-resolved transmission spectrum (PRTS)curve, the phase retardation of quartz wave plate can be determined at a wide spectral range from 200 to2000 nm obviously. Through accurate judgment of extreme points of PRTS curve at long-wave band, the physical thickness of quartz wave plates can be obtained exactly. We give a measuring example and the error analysis. It is found that the measuring precision of thickness is mainly determined by the spectral resolution of spectrometer. 相似文献
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He P 《The Journal of the Acoustical Society of America》2000,107(2):801-807
Traditional broadband transmission method for measuring acoustic dispersion requires the measurements of the sound speed in water, the thickness of the specimen, and the phase spectra of two transmitted ultrasound pulses. When the sound speed in the specimen is significantly different from that in water, the overall uncertainty of the dispersion measurement is generally dominated by the uncertainty of the thickness measurement. In this paper, a new water immersion method for measuring dispersion is proposed which eliminates the need for thickness measurement and the associated uncertainty. In addition to recording the two transmitted pulses, the new method requires recording two reflected pulses, one from the front surface and one from the back surface of the specimen. The phase velocity as well as the thickness of the specimen can be determined from the phase spectra of the four pulses. Theoretical analysis and experimental results from three specimens demonstrate the advantages of this new method. 相似文献
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A method is described of measuring the thickness of thin films by using white light fringes obtained in a double pass Michelson interferometer. The method is suitable for the determination of thickness ranging from 15 nm to 2500 nm. 相似文献