Objective lens for an optical pickup apparatus

摘要

An objective lens for use in an optical pickup apparatus, comprises an objective lens satisfying the following expression: 0.01≦̸|δSA3obj/δλ|<0.1 (λrms/nm), where δSA3obj/δλ represents the wavelength dependency of the 3rd order spherical aberration of the objective lens when the oscillation wavelength is fluctuated between ±2 nm.