出典:Wikipedia
出典:『Wikipedia』 (2010/11/05 05:20 UTC 版)
A lens clock is a mechanical dial indicator that is used to measure dioptric power of a lens. It is a specialized version of a spherometer. A lens clock measures the curvature of a surface, but gives the result as an optical power in diopters, assuming the lens is made of a material with a particular refractive index.