| 摘要 |
An optical pickup that can be downsized is suggested. The optical pickup includes: a collimator lens positioned on an optical path of a laser beam between a laser diode and an objective lens; and a collimator lens moving unit for moving the collimator lens along the optical path of the laser beam in a direction approaching the objective lens or a direction moving away from the objective lens; wherein a reference position of the collimator lens where the laser beam which has transmitted the collimator lens becomes parallel rays is set at an end or an approximately end of a movable range of the collimator lens that is closest to the objective lens; and wherein the objective lens is formed so that spherical aberration occurring in the laser beam which is made to converge on an outermost recording layer of the multilayered optical disc that is closest to the objective lens can be cancelled by spherical aberration occurring in the laser beam entering the objective lens through the collimator lens located at the reference position. |
