Lens designing method and objective lens apparatus with two lenses

摘要

A method for designing an objective lens apparatus formed by at least two lenses, a first lens and a second lens, which includes the steps of: measuring aberration which occurs when a light beam is converged by the first lens; setting the first lens is set such that the aberration occurring in the first lens satisfies Mar+E,acu e+EE chal's criterion, in accordance with the measurement results; measuring aberration which occurs when a light beam is converged by the first lens and the second lens; and setting the second lens such that the aberrations occurring in the first lens and the second lens satisfy Mar+E,acu e+EE chal's criterion, in accordance with the measurement results. Accordingly, an objective lens apparatus with a small aberration and a large numerical aperture NA can be designed by this method.