Application of a commercially available displacement measuring interferometer to line scale measurement and uncertainty of measurement

Abstract

The need for high resolution detecting line scale graduations is reached by increasing of the requirements of the calibration system. At NIS, an adapted technique is used to meet high requirements in the line scale graduation measurements. The proposed technique comprises of an automatic moving stage, data storage system, and a magnifying microscope coupled with a digital camera for precise detection of scale edge or centre. In many metrological applications, wavelengths of laser sources are being used as secondary definitions of the meter to serve in the precise measurement using dynamic interferometer. In our technique, displacement measuring interferometer with its optical components are set on the measuring system to display the length scale in terms of He-Ne laser wavelength which increase the efficiency and the accuracy level. The calibration procedure depends on the static mode technique. Both of the geometrical errors and alignment errors are compensated. In the present paper, system description, calibration method, results, and uncertainty are discussed in details.