Meter for testing progressive multifocus lenses

摘要

The present invention provides a lens meter capable of accurately measuring the optical characteristics of a lens including additive diopter and of providing highly reliable data representing the optical characteristics of the lens. The lens meter projects measuring light through a target mark on a lens, focuses an image of the target mark in a target image on a photo-detecting device, and determines the optical characteristics of the lens on the basis of a locus of the target image detected by the photo-detecting device. The lens meter comprises an additive diopter measuring mode selector switch, a control means for shifting the lens to position measuring points distributed at predetermined intervals on the lens successively on a measuring optical axis and measuring the refractive power of the lens at each measuring point, a position detecting means for detecting the distance of each measuring point from a predetermined reference point, and a display means for displaying the relation between the distance of the measuring point from the reference point and the variation of the spherical refractive power of the lens.