| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical pickup which uses one objective lens to perform recording or reproducing of an optical recording medium by a lot of light beams different by wavelengths and simplifies an optical system and can be made small-sized. SOLUTION: An actuator 12 constitutes an optical path length adjustment means which adjusts the optical path length (called the distance hereafter) from a compound optical element 10 to an objective lens 14 by moving the compound optical element 10 in the direction of the optical axis of the objective lens 14, namely, along a light beam emitted from a light source part 1006. An aperture limit filter 15 is provided so as to face the surface on the light source part 1006 side of the objective lens 14 and is so constituted that the aperture of the objective lens 14 may be limited differently between wavelengths λ1 and λ2 of a light beam B, that is, the radius of the objective lens 14 may be different between them. |
