| 摘要 |
PROBLEM TO BE SOLVED: To facilitate reproducing from other recording media such as a CD (compact disk) by an optical system for a predetermined recording medium such as a DVD(digital versatile disk). SOLUTION: A lens 42 includes a surface A having a first surface shape and a surface B having a second surface shape, and luminous fluxes transmitted through these surface A and B are converged in different positions by an object lens. In this lens 42, a light shutting-off plate 51 shuts off, among lights made incident on the surface B, those light in the track direction of the recording medium. |
