Comparison and analysis on the accurate measurement of spherical curvature radius

A fundamental issue in spherical optical manufacturing process is how to measure the radius of curvature accurately. Due to the high precision requirement for some advanced optics applications, the accuracy of the measurement is usually crucial. In this paper, kinds of spherical curvature radius methods that use spherometer, laser interferometer and profilometer are introduced, the error sources of these methods are analyzed. A series of measurement experiences with radius rang from R 7.65mm to R790.5mm are carried out and the results are analyzed according to measurement error theory. Consequently the advantages of the three kinds of instruments in radius measurement are obtained.