Author(s)

M.B. McCarthy, J.W. Nunn and G.N. Rodger

Abstract

The National Physical Laboratory (NPL) has a long tradition in the calibration of optical length standards, a service which continues today in the form of line scales, graticules and stage micrometers. Recently it has improved the specifications of its affordable range of optical scales which include high specification standards for linewidth, two -dimensions and image analysers. This paper describes these standards, a recently launched range of quartz *NPL High Precision Line Scales' together with the apparatus used to calibrate them. The scales serve to verify the calibration of customers' optical measuring systems and they are regularly supplied to a broad range of companies and institutes world wide. 1 Introduction Recent rapid developments in micro-engineering, particularly associat

Keywords