引入平板系统对量块长度测量结果的影响

以光谱辐射线的波长作为标准、以光波干涉条纹小数部分重合的原理设计的光波干涉仪、用直接测量的方法测量量块长度时，必须引入一系列大孔径（Φ≥５０ｍｍ）的平板干涉系统，本文讨论各平板各自的平面度在干涉仪光学系统中的相互叠加对量块长度的测量结果的影响     

干涉条纹小数的测量

对高精度干涉条纹小数测量的方法进行了系统的介绍.就干涉条纹小数的定义、暗条纹中心的确定、量块中心长度测量的起始和终了位置进行了较全面的分析,实现了不确定度为2 nm的干涉条纹小数的测量.引用实验与国际比对结果理论分析予以验证.     

接触式干涉仪的数字化改造

为解决接触式干涉仪使用过程中对线不准、人工读数误差大等问题，采用图像采集与处理技术对其进行数字化升级改造。使用工业相机，将实时采集的干涉条纹图像传输至计算机，同时基于灰度投影法，实现自动定度与零级干涉条纹中心的定位，根据零级干涉条纹中心的偏移量，计算被测量块与标准量块的差值，并将相关测量信息自动存储至数据库。实验表明：改造后的接触式干涉仪性能稳定可靠，能准确计量检校三等及以下的量块长度。     

双波长激光量块干涉仪减小量块中心长度测量不确定度的措施

该文总结了双波长激光干涉仪研制过程中减小量块中心长度测量不确定度的几项重要措施,该干涉仪对量块中心长度的测量不确定度达到(0.02±0.2L)μm,并已成功应用于高等级量块的自动测量。     

双波长激光量块干涉仪研制

本文介绍了双波长激光量块干涉仪的工作原理,详细描述了仪器的光学,机械设计以及干涉图象处理和量块中心长度自动判读技术,该干涉仪满足1等量块的测量不确定度要求,目前已用于高等级量块的自动化测量。     

一等大量块(125～1000 mm)检定装置

量块的测量是长度计量的重要基础.文中的装置采用了高精度的633 nm碘稳频氦氖激光器和543 nm热稳频氦氖激光器各一台,分别将不同波长的激光光束入射到典型的迈克尔逊干涉仪中,使放置在测量光路中的量块与平晶研合在一起的组合体和参考镜进行干涉,利用CCD摄像机获取干涉图像,同时测量量块温度及空气折射率(或环境参数),一同输入计算机中进行处理计算得到测量结果.对于125～1000 mm量块的测量难点是保证温度要稳定、均匀、偏离20 ℃的范围要小.为此,设计了可高精度控温的仪器箱,可调节温度到17～23 ℃,温度变化率小于0.01 ℃/h,从而实现量块线膨胀系数的测量.该装置的量块长度测量不确定度达到U99 =0.02 μm+0.2×10-6 L,量块线膨胀系数测量的不确定度可达U99 =0.2×10-6 ℃-1.     

基于单稳频激光的端面距离微尺寸测量方法

搭建了一种用于端面距离微尺寸测量的干涉光路,分别以频率高度稳定的532nm波长激光和波长不确定度水平相对较差的633nm波长激光作为光源进行照射以获取干涉图样。使用电荷耦合器件(CCD)传感器获取干涉图样,采用数字图像处理手段清晰化干涉图样,并利用条纹的像素距离计算干涉条纹级次差的小数部分,用多波长的小数重合法计算端面间距。通过系统的软件部分,利用数字图像处理的手段对干涉图像的质量进行优化,在较为简单的实验条件下实现精度较高的端面距离微尺寸测量。     

多波长测量技术

给出了3种多波长测量技术的应用实例,采用多波长二极管激光器干涉仪测量表面轮廓,3个二极管激光器分别发射780nm、823nm和825nm3种近红外光波,可以得到2个近似15μm和29μm的合成波长,激光二极管的注入电流用1MHz左右的3种不同频率调制,以获得干涉仪的相位调制,这3个干涉信号用1个光电检测器和锁相放大器检测,采用同样的干涉仪,仅用2种波长进行了圆度偏差测量,论述了相移干涉测量技术,其试件的长度表示为光源波长的倍数,如果只使用1种波长,则要求确切知道整数干涉级;而使用多种波长,如532nm、633nm和780nm时,可得到几个独立的长度,此时整数衍射级不同,可以通过“精确小数法”计算得到,PTB精密干涉仪长度测量不确定度很小,其单值性范围约0.6mm,因此其近似的长度估算足以满足超精密长度测量的要求。     

可调合成波长链绝对距离干涉测量

本文提出一种利用半导体激光器的波长调谐特性实现的可调合成波长链绝对距离干涉测量方法 ,针对不同的待测距离 ,可选择不同的合成波长链 ,完成对待测距离的由粗测到精测的整个过程。文中基于这种方法构建了干涉测量系统 ,该系统利用压电陶瓷调制的在一条直线上的两个双光束干涉仪 ,使待测距离被包含于一个交流信号的相位项中 ,从而使小数条纹的测量转化为相位测量 ,合成波干涉条纹的小数级次由单波长干涉信号的相位测量值计算得到。文中以外尺寸测量为例描述了实验装置 ,实验结果表明 ,在现有的测量系统和实验条件下 ,待测距离小于 5mm时的测量极限偏差优于 2 0μm。     

“小数重合法”的计算机简易算法

1小数重合法的应用在柯氏干涉仪上检测量块长度．其测量原理为其中，人为所用光波波长，可查得。如何求（＋＋。）值便是“小数重合法”所要解决的问题。对于采用几种不同波长的光波则可列出L一（尺十E卜几。／2（2）其中人可分别查出，小数。。可直接从仪器中读出。根据预先在其它仪器测出的量块尺寸，可选择符合式（）的厂；值，则被测长度L的精确度即可求得。在实际测量中，首先将量块的标称长度和选用的红、黄、绿、紫四种光波波长分别代人（2）式，算出四组（K。＋。。），只取其中的小数部分。；，得出一组理论小数’。、”黄、”绿…     

Differential wavelength-scanning heterodyne interferometer for measuring large step height

An interferometer based on the differential heterodyne configuration and wavelength-scanning interferometry for measuring large step heights is presented. The proposed interferometer is less sensitive to environmental disturbances than other interferometers and can accurately measure interference phases. A tunable diode laser is utilized to illuminate the interferometer and thus solve the phase ambiguity problem. Counting the interference fringes as the wavelength is scanned through a known change in wavelength directly determines the step height. Three gauge blocks of different lengths, 5, 10, and 50 mm, are individually wrung on a steel plate to simulate large step heights. Comparing the results measured by the proposed interferometer with those by the gauge block interferometer reveals that the accuracy is approximately 100 nm.     

Phase-stepped gauge block interferometry using a frequency-tunable visible laser diode

Frequency changes induced by bias or temperature modulation of injection diode lasers can provide an economical and effective method of applying phase-stepping interferometry to optical metrology. However, the intrinsic frequency instability of these devices limits their use in gauge block interferometry where precise and repeatable phase steps must be maintained simultaneously on two discontinuous surfaces and over relatively long path lengths. We demonstrate a method using a visible injection diode laser, the frequency of which is locked by using a Fabry-Perot interferometer. Small changes to the length of the Fabry-Perot interferometer shift the frequency of the laser producing proportional and repeatable phase steps to the gauge block interferogram. This method has been successfully implemented with a Fizeau-type gauge block interferometer with a phase measurement resolution of 0.005 lambda. The phase data are then processed to map the surface form of gauge blocks up to 100 mm in length and to objectively assess surface shape parameters.     

An interferometer for use with gauge blocks up to 1000 mm with laser and white-light sources

A displacement interferometer is described for measuring gauge blocks, in which a spatial filter is used to combine a laser beam with a white-light beam, and the length of the block is calculated from the phase differences of the laser signal corresponding to the centers of gravity of the achromatic fringes from the gauge and from the reference plate. __________ Translated from Izmeritel’naya Tekhnika, No. 9, pp. 3–5, September, 2006.     

一种基于Matlab的干涉条纹自动处理方法

对接触式干涉仪量块检定时产生的两种干涉条纹进行了研究,图像整体采用傅里叶级数曲线拟合法,实现干涉暗条纹大致定位.局部采用最小二乘二次曲线拟合法,确定干涉暗条纹中心的精确位置及暗条纹个数.利用Matlab和VC平台进行编程,快速有效地实现了干涉条纹中心位置的自动判读. 该方法已应用在中国计量科学研究院接触式干涉仪的量块检定中.     

大量程纳米级光栅干涉位移测量

针对传统光栅干涉仪中测量范围和分辨率难以同时提高的问题,提出利用单根大长度、低线数光栅实现大量程、高分辨率位移测量的方法.首先利用长度400mm,栅距10μm计量光栅的±5级衍射光生成条纹图,实现了条纹的10倍光学细分.然后提出一种基于傅里叶变换时移特性的条纹细分新方法,利用相邻两帧条纹图同一位置处相位的变化实现了高达1000倍的条纹电子细分.在此过程中,针对能量泄漏对傅里叶变换法相位提取精度的影响,提出条纹图整周期裁剪的方法,使条纹细分精度至少可达到1/1000条纹周期.仿真和实验结果表明,系统具有纳米级的分辨率和优于10nm的测量精度.     

用相位偏移干涉法精确测量量块长度

讨论了相位偏移干涉技术的原理、常用的算法和小数重合法的应用。在分析了传统的柯氏干涉仪的量块测量方法基础上 ,提出运用相位偏移干涉法的量块测量法 ,最后给出了量块测量的数据。     

Precise interferometric length and phase-change measurement of gauge blocks based on reproducible wringing

A modern fringe-pattern-analyzing interferometer with a resolution of 1 x 10(-9) and without exclusion of systematic uncertainties owing to optic effects of less than 1 nm was used to test a new method of interferometric length measurement based on a combination of the reproducible wringing and slave-block techniques. Measurements without excessive wringing film error are demonstrated for blocks with nominal lengths of 2-6 mm and with high surface flatness. The uncertainty achieved for these blocks is less than 1 nm. Deformations of steel gauge blocks and reference platens, caused by wringing forces, are investigated, and the necessary conditions for reproducible wringing are outlined. A subnanometer uncertainty level in phase-change-correction measurements has been achieved for gauge blocks as long as 100 mm. Limitations on the accuracy standard method of interferometric length measurements and shortcomings of the present definition of the length of the material artifact are emphasized.     

相位扫描法制作变栅距光栅

提出了一种制作变栅距(VLS)光栅的相位扫描方法。该方法的主要装置包括一个用于控制刻划机运动的光栅干涉仪和一个相位扫描机构。如果调整光栅干涉仪,保证接收场中只有两条干涉条纹,然后改变用于对条纹进行计数的光电传感器的位置,就可以刻划出具有变栅距的刻槽。对光电式光栅刻划机的控制系统和结构都做了详细论述。按照上述方法成功刻划出了试验性的VLS光栅,它的最小栅距增量为0.33nm,并对在制作过程中产生的误差进行了讨论。采用测量衍射角的方法进行了栅距检测试验,由变栅距光栅和等栅距光栅作出的拟合曲线表明:相位扫描方法是加工具有亚纳米栅距增量的VLS光栅的有效方法,该方法对超精密定位也具有借鉴作用。     

Ring interferometer for two-sided measurement of the absolute lengths of end standards

Special features of a two-sided interferometer based on a ring optical scheme previously proposed [V. M. Khavinson and L. F. Khavinson, in Investigations in the Field of Length and Angle Measurements, N. P. Gerasimov, ed., Proceedings of the D. I. Mendeleyev Institute for Metrology (Energoatomizdat, Leningrad, 1983), pp. 14-18], which exploits an alternative measurement method to the conventional method for measuring absolutely the lengths of precision gauge blocks. Both measuring surfaces of a gauge are viewed directly without an auxiliary platen wrung onto one of them. The two-sided method results in improved consistency of measurement results because the elimination of wringing avoids the contact error that can occur in the gauge length obtained when the conventional method is used. A variety of means to control the optical phase differences in the interferometer are considered.