Objective lens and optical pickup apparatus

摘要

An objective lens having a doublet structure and a numerical aperture of 0.7 or more and an optical pickup apparatus having this objective lens are adapted to an optical recording medium having a high information recording density, the objective lens being structured such that at least one side is formed into a aspheric surface and the lens elements (3, 4) are made of low-diffusion glass having an Abbe's number of 40 or greater.