Patent ID: 6876501

Claim:
An objective lens for recording and/or reproducing an optical information recording medium, comprising: a first lens having a positive refractive power and including a first surface and a second surface in this order from a light source side of the objective lens; and a second lens having a positive refractive power and including a third surface and a fourth surface in this order from the light source side of the objective lens, wherein the first lens and the second lens are aligned in this order from the light source side of the objective lens, wherein the first lens and the second lens are respectively made of a material having a specific gravity of 2.0 or less, wherein the obiective lens satisfies the following conditional formula: NA≧0.70, where NA represents a predetermined image side numerical aperture necessary for recording and/or reproducing of the optical information recording medium, and wherein at least two surfaces are an aspherical surface among the first surface, the second surface, and the third surface.