新型光干涉法纳米级润滑膜厚度测量仪

润滑膜厚度的测量是开展纳米量级薄膜润滑状态研究的关键问题。利用光干涉法相对光强原理研制出一种纳米级润滑膜厚度测量仪,在低速低载荷条件下对点接触纯滑动润滑接触中心区润滑膜厚度进行测量,并讨论接触中心区和润滑膜厚度与速度和载荷之间的关系。结果表明:已测量的膜厚值已达到纳米量级,在设定工况下润滑膜厚度随速度增大而增大,随载荷增大而减小;比较Hamrock-Dowson公式计算结果和实验结论证明,这种仪器能有效实现对纳米级润滑薄膜厚度的测量。     

三波长光干涉法测量磁盘/磁头纳米级气膜厚度

给出三波长光干涉测量纳米级薄膜厚度的方法。通过对某负压磁头／玻璃盘空气薄膜的测试表明：三波长光干涉法具有精度高、容易实施等优点，能够满足磁盘／磁头润滑副设计、制造及研究的需要。     

目标激光反射率测试方法研究

反射率的测量可分为两种方法绝对测量法(直接测量法)和相对测量法(比较测量法).当被测反射功率与入射功率相比时,则为绝对测量;先测出被测目标的反射功率和已知反射率的标准反射板的反射功率,再用其比乘以已知的标准反射板的反射率,就可以得到被测目标的反射率,这种测量的方法称为相对测量.本文论述了一种采用相对测量反射率测试方法,用于激光反射率的测量,并对测量进行了分析.     

基于白光干涉的纳米级生物膜层厚度测试的研究

提出了利用光学干涉原理在光纤传感器端面上直接测量生物免疫反应的方法，能够测试到纳米级厚度生物膜层的亚纳米级厚度增加量。将生物膜(如抗原)固定在光纤探针端面上，入射光在光纤生物层、以及生物层一空气的界面处两次反射，由于两束反射光之间存在光程差，所以产生干涉现象，通过分析干涉谱线可以测量出抗原层的厚度。当抗原和抗体发生免疫反应后，生物膜层的厚度产生变化，干涉谱线产生移动，通过检测干涉谱线的移动来判断样本溶液中是否存在待测抗体。能够测试出亚纳米级生物膜厚度的增加量。给出了测试曲线。该方法测试精度高，结果可靠，测试系统简单，具有较强的实用性，并能够进行实时测量。     

干涉测量法的最近展况——根据斋藤弘义教授讲学记录整理

一、序干涉测量法是把光的波长做为一把尺子,用来测量长度、厚度、面形误差等的一种测量技术.这种技术在很早以前就已被广泛地利用在测量中.1960年激光的出现给干涉测量技术带来了根本性的变化.激光具有足够的时间相干和空间相干,可提高干涉条纹的对比度,避免用扩展光源给测量中带来的操作上的麻烦,使得一般人都可以利用干涉法进行测量.     

科技新成果信息

NGY-2型纳米级润滑膜厚测量仪该测量仪是根据相对于涉光强原理设计的新一代润滑膜厚度和形态测量以及其他纳米量级透光薄膜(如SiO_2等)的厚度测量,并且可以进行动态跟踪监测,给出接触区内各点的薄膜厚度分布图、专利申请号:93104866.4     

季戊四醇油酸酯膜厚测量及薄膜润滑研究

运用光干涉法相对光强原理,通过纳米级润滑膜厚度测量仪测量了不同温度、不同载荷下纳米间隙中环境友好润滑剂季戊四醇油酸酯的油膜厚度。探究了膜厚与速度、载荷、温度之间的关系,观察了薄膜润滑现象。结果表明：在对数坐标系下,膜厚与速度具有一定的线性关系,在速度较高时,线性关系更强,润滑剂具有流体效应。载荷对膜厚的影响远小于速度对膜厚的影响,温度对膜厚的影响主要表现在温度越高时,润滑剂的黏度越低,润滑剂的膜厚越薄。     

动态线偏振光散射纳米颗粒粒度测量法的研究与分析

多重散射是传统动态光散射法测量纳米颗粒溶液浓度上限受到限制的主要原因。为此文中提出了动态线偏振光散射纳米颗粒粒度测量法,通过改变颗粒入射光和散射光的偏振状态,降低颗粒间多重散射的影响。现利用Mie散射理论分析了入射光与散射光偏振状态之间的关系,并通过实验方法探知偏振光在散射介质中的传输特性,揭示了在动态光散射中使用垂直偏振光作为入射光的实验依据。最后对动态线偏振光散射颗粒测量法和传统光子相关光谱测量法进行了实验及分析,通过两种方法的比较,验证了上述理论的正确性。     

白光反射谱测薄膜厚度实验

本实验利用白光的反射谱采测薄膜的厚度,利用单色仪测量不同波长光的干涉光强度,把对条纹的测量转变为对不同波长干涉光强度的测量,既可以手动也可以利用数据采集系统自动采集和处理数据,使操作和测量更加简洁方便.     

双波长干涉显微镜波长的双约束标定

作为测量的精度来源,双波长干涉显微镜的光波长需要精确标定以溯源至长度基准.本文提出了一种基于两个光波长之间关系、波长与长度基准之间约束的标定方法.理论分析得到了表面重构误差与波长误差之间的关系,认为表面跳变与高度对两个光波长具有足够的约束自由度,并基于理论分析提出了一种双约束的标定方法.该方法通过测量斜平面与标准高度台...     

LOW FLYING HEIGHT MEASUREMENT WITH MULTI-WAVELENGTH INTERFEROMETRY

A method for measurement of ultra-low flying height in head-disk spacing is described. Three different wavelengths are selected out from white light by filters to measure the spacing simultaneously. Besides solving the ambiguity problem, a more reliable result is achieved by using weighted average of measurement results from three different wavelengths, where the weight is dependent upon spacing. Fringe-bunching correction algorithm （FBC） and spot-tilling technique are adopted to suppress calibration and random errors. Moreover, incident bandwidth correction （IBC） method is introduced to compensate the error caused by low monochromaticity of incident light. Based on dynamic flying height tester （DFHT Ⅱ）, with the redesigned of photo-electric conversion and signal acquirement module, an instrument has been developed. And comparing the experimental data from the instrument with those from a KLA-FHT D6, the discrepancy is less than 5%. It indicates that the instrument is suitable to perform ultra-low flying height measurement and satisfies the reauirement of magnetic heads manufacturing.     

The Head/Tape Interface: A Critical Review and Recent Results

Modeling and measurement techniques for the head/tape interface are discussed. With the advent of contact between the head and tape, both the numeric models and experimental procedures need to be modified to account for the contact. In the field of head/tape interface modeling, the basic Green's function, finite difference, and finite element solution techniques are presented. The asperity compliance curve is introduced to calculate the contact pressure between the head and tape resulting from compression of surface asperities. Modern experimental measurements of head/tape spacing use monochromatic interferometry. The basic theory is presented, and the need for multi-wavelength interferometry is described to improve measurement resolution at extremely close spacings.     

Fast fiber-optic multi-wavelength pyrometer

A fast fiber-optic multi-wavelength pyrometer was developed for the ultraviolet-visible-near infrared spectra from 200 nm to 1700 nm using a CCD detector and an InGaAs detector. The pyrometer system conveniently and quickly provides the sufficient choices of multiple measurement wavelengths using optical diffraction, which avoids the use of narrow-band filters. Flexible optical fibers are used to transmit the radiation so the pyrometer can be used for temperature measurements in harsh environments. The setup and calibrations (wavelength calibration, nonlinearity calibration, and radiation response calibration) of this pyrometer system were described. Development of the multi-wavelength pyrometer involved optimization of the bandwidth and temperature discrimination of the multiple spectra data. The analysis results showed that the wavelength intervals, Δλ(CCD) = 30 nm and Δλ(InGaAs) = 50 nm, are the suitable choices as a tradeoff between the simple emissivity model assumption and the multiple signal discrimination. The temperature discrimination was also quantificationally evaluated for various wavelengths and temperatures. The measurement performance of the fiber-optic multi-wavelength pyrometer was partially verified through measurements with a high-temperature blackbody and actual hot metals. This multi-wavelength pyrometer can be used for remote high-temperature measurements.     

双波长集成光栅干涉微位移测量方法

介绍了一种基于双波长激光的集成光栅干涉位移检测方法,利用该方法对硅-玻璃键合工艺制作的集成光栅位移敏感芯片进行了测试实验。实验系统主要由敏感芯片、波长为640nm和660nm的双波长半导体激光器、双光电二极管及检测电路组成,敏感芯片则由带反射面的可动部件和透明基底上的金属光栅组成。入射激光照射到光栅上产生衍射光斑,衍射光的光强随可动部件与光栅之间的距离变化,通过分别测量两个波长的衍射光强信号并交替切换选取灵敏度较高的输出信号,实现了一定范围内的扩量程位移测量,并得到绝对位置。实验结果表明,利用双波长集成光栅干涉位移检测方法测得敏感芯片可动部件与基底光栅的初始间隙为7.522μm,并实现了间隙从7.522μm到6.904μm区间的高灵敏度位移测量,其噪声等效位移为0.2nm。     

波长轮换与相移扫描相结合的表面形貌测量系统

用光学显微干涉法进行表面形貌测量时其深度测量范围的扩大和形貌测量精度的提高是一对矛盾。为此,本文设计出了一种基于波长轮换与相移扫描相结合的三波长表面形貌测量系统,并提出了一种基于椭圆拟合与相位差大小尺度相结合的相位提取与识别算法。将这种算法运用于多波长干涉图像的数据处理,有效地提高了形貌的整体测量精度,并拓展了深度测量范围。实验结果表明:在深度测量范围扩大近15倍的条件下,采用粗糙度国家基准校准的方波多刻线样板得到的表面粗糙度数据与校准数据的相对误差仅为4.12%,表明该系统在一定的深度范围内能够实现表面形貌的高精度测量。另外,针对该系统设计的多波长相位识别算法对环境噪声要求不高,可以支持系统的高噪声或在线测量。     

Interferometry Measurement of Lubricating Films in Slider-On-Disc Contacts

Interferometry proves to be an efficient way to measure thin lubricant film thickness. However, there are very few reports on the film thickness measurement of conformal lubricated contacts using optical interferometry due to experimental difficulties. In this article, a custom-built test apparatus is introduced, in which a lubricated conformal contact is made between a stationary fixed-incline slider and a moving transparent disc. With a flexible holder, the slider can be positioned in such a way that a specified inclination with respect to the flat disc plane can be obtained. When the disc rotates and the slider is loaded against it, lubricating films are generated. The minimum film thickness h _m at the exit can be determined by interference intensity changes. Measurement error correction in the film thickness was discussed. Case experiments were carried out using the new test apparatus. The credibility of the measurement system is validated by good correlation between the experiments and the theoretical results. The applicability is demonstrated by the film thickness measurement under different inclinations, loads, velocities, lubricants and slider materials. Amongst those case experiments, it is highlighted that the influences of solid/liquid interface properties on the lubrication behaviours can be clearly identified in terms of film thickness.     

Consideration and compensation for precision optical flying height measurement

It is a big challenge to determine ultra-low slider flying height accurately. The intensity interferometry flying height testing method is widely used to determine slider flying height. However, the intrinsic measurement errors of the method are becoming non-negligible with the decrease in slider flying height. Strategies have to be developed to minimize the errors. To measure flying height with a normal incidence optical flying height tester, a calibration process is required to determine several constants used in flying height calculation. In practice, the calibration is usually done simply by retracting the slider from the disk and measuring the intensity minima and maxima of the interferogram during the retracting process. It has been demonstrated that the single most important source of error in the flying height measurement is associated with errors in the determination of the intensity maxima and minima. In this work, the effects of optical filter, the responding frequency of photodetector, and the lack of the first order intensity minimum on the determination of the intensity maxima and minima are studied. Methodologies to minimize the errors in flying height measurement caused by the above factors are developed.     

Experimental study of real roughness attenuation in concentrated contacts

The understanding of the processes involved in the in-contact deformation of surface roughness represents one of key factors in increasing lubrication capabilities of highly loaded machine components. Two main approaches have been developed in an effort to understand the changes of initial surface topography within highly loaded contacts to provide detailed information about lubrication film thickness and pressure distribution in the vicinity of roughness features. The first approach considers the real surface topography while the other uses the simplified topography features. Numerical solutions based on measured topography data can provide the film thickness and pressure distribution around asperities of realistic scale; nevertheless, obtained results are typically limited to the specific topography configuration measured from a very small area of rubbing surface. That is why some researchers have considered harmonic features of various wavelength and amplitudes to explain the behaviour of real roughness.This study is focused on the experimental validation of an approach based on Fourier decomposition of the surface roughness into harmonic components. Two optical measurement techniques—phase shifting interferometry and thin film colorimetric interferometry are combined to provide the undeformed surface topography and film thickness data within the elastohydrodynamic contact formed between a smooth disk and a ball having a real rough surface. The results obtained under pure rolling conditions not only confirmed the general principle that roughness deformation is component dependent and that long wavelengths deform more than short wavelengths, also the observed deformation for different components agreed well with the data predicted by the theory.     

Characterisation and laboratory investigation of a new ultraviolet multi-wavelength measuring system for high-temperature applications

In the framework of the HiTeMS project of the European Metrology Research Pogramme (EMRP) a new multi-wavelength device for measurement of high temperatures in industrial applications was developed at INRIM. The apparatus takes advantage of the ultra-violet operation with working wavelengths from 350 nm up, which reduces the possible errors connected with the multi-wavelength approach. The instrument has been characterised in terms of optical and electronic behaviour and some laboratory trials were carried out to verify the reliability of the multi-wavelength approach. The true temperature of a blackbody source at 1300 °C with optical windows of unknown spectral transmittance interposed has been defined. By applying an approach that allows a result to be accepted when a threshold limit is reached, it was found that, when an acceptable result can be obtained, errors are comprised within less than 1% of the temperature of the source. Three others single-band thermometers, at 508 nm, 650 nm and an IR broadband 0.8–1.1 μm, were also used to the purpose of a comparison. It has been found that, when the multi-wavelength approach is applicable, it provides generally better or in few cases, at worst similar results of corrected single-wavelength thermometers.     

面接触油膜润滑测量系统

介绍了一种能够实现面接触油膜润滑测量的试验系统,该系统以静止的刚性滑块和旋转的透明玻璃盘组成润滑副。滑块的定位采用柔性并联机构,可进行面接触倾角的微小调节。油膜厚度测量采用多光束干涉技术。照明采用激光外部同轴照明,可有效扩大图像视场和膜厚的测量范围。利用该系统测量了恒倾角面接触薄膜润滑的膜厚特性和摩擦力特性,结果与已有理论有较好的一致性。