共查询到19条相似文献,搜索用时 140 毫秒
1.
2.
3.
4.
5.
6.
对二维线纹标准样板进行溯源测量时,需要对十字刻线进行高分辨力瞄准。利用二维动态光电显微镜,将二维样板十字刻线分别成像在相互垂直的两组狭缝上,狭缝宽度与刻线像的宽度基本一致,方向与刻线像平行,且在像空间上沿宽度方向错开约一个狭缝宽度的距离。当二维线纹样板沿某一方向运动时,对应方向被测刻线的像先后呈现在一组狭缝中,导致通过该组狭缝的光通量依次发生变化,对应的两个光电接收器的电信号存在相位差;信号处理系统根据两路电信号的相位关系,在信号交叉位置发出瞄准脉冲,锁定坐标测量系统,即得到该方向被测刻线的位置;分别对十字交叉刻线的两条刻线进行瞄准,即可得到对应交叉点的坐标。 相似文献
7.
三等金属线纹尺主要用于检定水准标尺、钢直尺以及准确度较低的线纹尺。目前,使用中的线纹尺多由黄铜、锌白铜、不锈钢等材料制成。在传统检定中,多采用与二等金属线纹尺进行比较的测量方法。随着科技的发展,激光越来越多地被应用在线纹尺的检定中。根据标准器选取和测量方式的不同,线纹尺的检定方法可分为两种形式:以激光干 相似文献
8.
9.
10.
11.
介绍了2 m比长仪系统的组成,对其采用光电显微镜动态瞄准刻线和激光干涉测长原理进行了分析,研究了提高刻线瞄准精度和激光干涉测长精度的方法及利用现代电子技术实现刻线信号和干涉信号自动同步快速处理方法。自动信号处理系统基于FPGA现场可编程电路技术和计算机技术。通过对金属线纹尺测量的实验表明,依据JJG 331—1994激光干涉比长仪检定规程进行实验,2 m比长仪单次最佳刻线瞄准精度优于10 nm(1σ),对其测量的不确定度分析表明,对于测量高质量的高等别线纹尺,其测量不确定度U=(20+40 L)nm(k=2)。 相似文献
12.
Klann M Koch C 《IEEE transactions on ultrasonics, ferroelectrics, and frequency control》2005,52(9):1546-1554
The measurement of spatial cross sections of ultrasound pressure fields is an essential element of exposimetry of ultrasonic medical equipment. An optical technique is presented that allows the two-dimensional (2-D) determination of ultrasound pressure using an optical multilayer hydrophone in which a laser beam with suitable wavelength is partially reflected from a dielectric optical multilayer system. By detecting the change in reflectivity of the multilayer coating induced by the incident ultrasound, the pressure time waveform can be determined. A 2-D data acquisition covering an area of at least 15 mm x 5 mm was realized by two complementary approaches. A serial detection scheme was set up by scanning the sensing point across the area of interest by a micromechanically engineered scanning mirror and acquiring pressure time waveforms sequentially and pointwise. This allows the measurement of repeating ultrasonic waveforms with a spatial resolution of better than 70 microm and a minimal detectable pressure of 50 kPa (bandwidth: 50 MHz) in a few seconds. In an alternative approach exploiting the parallel processing capabilities of a charge-coupled devices (CCD) camera chip, the probe was strobe-illuminated by a large-diameter collimated beam of a pulsed laser diode. The 2-D pressure distribution at a particular moment was derived from captured reflectivity distributions with a spatial resolution of 75 microm. By successive delaying of the laser pulse with respect to the ultrasound pulse, the complete 2-D pulse waveform was acquired with high spatial resolution. Measurement results on ultrasound fields from plane and focusing transducers are presented and compared to simulation results. Individual advantages and drawbacks of both approaches are discussed. A combined setup merging both detection schemes into a single device was developed and represents a milestone on the way toward constructing an optical ultrasound measuring camera. 相似文献
13.
阐述了2 m激光干涉测长基准装置工作原理及系统组成,以线间距测量功能为基础,研究了接触式和非接触式的几何测长对准方法,实现了其测长功能拓展应用。介绍了实现纳米精度测长的技术措施。对称布局的双光电显微镜同步扫描测量接长的方式实现2 m刻线间距测量,信号处理系统具有标准间距位置脉冲发生功能,可以实现位移传感器动态触发校准和其它应用。对于高质量的线纹尺,2 m激光干涉测长基准装置单次测量刻线间距的最佳瞄准精度优于10 nm(1σ),1 m测量范围内的线纹测量不确定度U=(20+40 L) nm (k=2)。 相似文献
14.
15.
The Linnik tomographic (sectional X-ray diffraction analysis) microscope for measurement of the spatial distribution of the
index of refraction within optically transparent (phase) objects is described. The microscope is constructed on the base of
the MII-4 microinterferometer with a laser lighting source and constitutes a fully automated integrated system that incorporates
a CCD camera, frame grabber, a computer-controlled PZT mirror, and a two-coordinate micrometer stage. The measurement system
and performance characteristics of the microscope are presented.
Translated from Izmeritel'naya Tekhnika, No. 10, pp. 18–22, October, 1998. 相似文献
16.
17.
针对目前国内激光测振系统价格昂贵、使用不便的问题,采用1 550 nm波段成熟的窄线宽光源和光纤元器件研制了一套低成本的全光纤激光测振系统原理样机。此原理样机光路部分采用马赫?泽德干涉仪结构,搭建了外差式激光干涉光路,参考光被40 MHz的声光调制器调制,与测量光在光电探测器表面发生干涉,产生原始的激光多普勒信号;信号解调部分采用相位解调法对原始激光多普勒信号进行解调,得到振动目标的运动特性,包括位移、速度和加速度信息。采用本单位的振动标准装置对其性能进行了测试,实验结果表明:在10 ~ 2 000 Hz的中低频振动范围内,1 550 nm全光纤激光多普勒测振系统峰值位移、速度和加速度的测量误差在-0.6% ~ 0.7%内。该系统在中低频段具有较高的测量准确度,且成本相对较低、操作便捷,具有技术借鉴价值。 相似文献
18.
基于多路激光跟踪干涉仪测长的坐标测量系统在大尺寸测量领域具有显著的优越性,准确标定系统参数是实现高精度坐标测量的关键。为了克服传统自标定方法的缺点,提出了一种采用标准长度的改进自标定算法。该算法首先在稳定的基座上设置固定点,在X、Y、Z方向分别产生用激光干涉法精确测得的标准长度,然后将标准长度用于构造自标定的优化函数。通过提高相应优化函数的权重,进一步提高坐标测量精度。通过仿真实验证明了该算法的可行性。采用独立的激光干涉仪验证系统在大尺寸范围内的测量精度,当测量点分布在距系统坐标系原点[7.0 m,8.3 m]区间内,两组实验误差均分布在[-9.5 μm,4.6 μm]区间内,结果表明所提出自标定算法可显著提高大尺寸空间坐标测量精度。 相似文献
19.
A multidirectional interferometer system is developed to determine the position and orientation of a stage moved in a two-dimensional (2-D) space. In this system four corner-cube prisms are mounted on the moving stage, and four laser beams are incident on the corner cubes in different directions. Moving distances in the observed directions are measured by laser interferometers. The position and orientation of the stage are calculated from the moving distances of the corner cubes. Some experiments are done on the 2-D moving stage with four interferometers, and measurement errors are estimated from redundant data. The estimated accuracy is higher than 0.2 microm for translation and 0.3 x 10(-3) deg for rotation for a measurement range of 0.5 mm and 0.5 deg. 相似文献