OBJECTIVE LENS, OPTICAL PICKUP DEVICE, AND OPTICAL RECORDING/REPRODUCING APPARATUS

摘要

An objective lens for converging light emitted from a light source onto an optical recording medium to record and reproduce information consists of a single lens that has at least one aspheric surface. The following conditional expressions (1) and (2) are satisfied: -0.90R1/R2 0.70d/f where R1 denotes a radius of curvature (mm) of a light source side surface near an optical axis, R2 denotes a radius of curvature (mm) of an optical recording medium side surface near the optical axis, d denotes a thickness (mm) on an optical axis, and f denotes a focal length (mm).