| 摘要 |
Disclosed is an objective lens used for an optical pickup apparatus to perform writing and/or reading of an optical information recording medium, comprising an antireflective film on a surface of a light source side, wherein a light flux of wavelengths including a wavelength λ1 of 380 nm≦̸λ1≦̸420 nm and a wavelength λ2 of 630 nm≦̸λ2≦̸810 nm, is condensed on the medium, a numerical aperture on the light source side with respect to the wavelength λ1 is within a range of 0.8-0.9, and that with respect to the wavelength λ2 is 0.7 or less, and a band of the antireflective film is within a range of 700 nm-800 nm in a state where a reflectance of a light flux perpendicularly entering a central portion of the surface in a wavelength region from 400 nm to 1200 nm is 3.0% or less. |
