| 摘要 |
There is provided an objective lens for an optical pick-up. The objective lens includes a first surface on a light source side, and a second surface on an optical disc side. The first surface has a convex shape. The objective lens is formed to be a single-element lens having a numerical aperture of 0.75 or more. In this configuration, the objective lens satisfies a condition: 0.95<(n−1)·tan &thetas;max<1.50  (1) where &thetas;max represents a maximum angle of a normal to the first surface with respect to an optical axis in an effective diameter of the first surface, and n represents a refractive index of the objective lens. |
