| 摘要 |
The present invention relates to an objective lens, an objective lens unit and an optical pickup apparatus. The objective lens is provided for an optical pickup apparatus recording or reproducing information by converging a light flux with a wavelength λ1 emitted from a light source onto an information recording surface of an optical information recording medium. The objective lens is formed of: a single lens having at least one aspheric surface. In the objective lens, an effective aperture, a thickness on an optical axis, a focal length, a numerical aperture, and a refractive index satisfy the predetermined conditional expressions. The objective lens unit is provided for an optical pickup apparatus and includes an aberration correcting element and the objective lens. |
