Patent ID: 8089705

Claim:
An objective lens for an optical pick-up, comprising: a first surface on a light source side; and a second surface on an optical disc side, the first surface having a convex shape, the objective lens being formed to be a single-element lens having a numerical aperture of 0.75 or more, the objective lens satisfying a condition: 0.95<( n− 1)·tan θ max <1.50 (1) where θ 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, wherein the objective lens satisfies a condition: −0.030<SC max /f<− 0.005 (2) where SC max represents a negative local minimum value of an offence against a sine condition of the objective lens, and f represents a focal length of the objective lens.