Optical pickup movable to control beam shift and field angle in an optical disk drive

Abstract

An optical pickup of an optical disk drive. The optical pickup includes a laser beam source for generating a laser beam; a pickup base having an objective lens for projecting the laser beam generated from the laser beam source to an information recording surface of an optical disk; a variation adjusting plate which is movably disposed on the pickup base to be moved in vertical and lateral directions, and has a rotational hole formed at a central portion thereof; and a rotation adjusting plate including a rotational section having a predetermined curvature which is inserted into the rotational hole of the variation adjusting plate, and with a laser beam source fixed therein, the rotation adjusting plate being rotated with respect to the variation adjusting plate. An optical system including a collimating lens and a reflective mirror is fixed to the pickup base. Since the light path with respect to the field angle and the beam shift is adjusted by moving and/or rotating the light emitting point of the laser beam source with respect to the light axis of the collimating lens, the size of the optical pickup becomes smaller. Further, since the collimating lens and the light source are fixed to the respective structures, the light path is controlled regardless of the focal distance of the collimating lens. Accordingly, if the focal distance of the collimating lens has to be lengthened, the beam shift and the field angle can be precisely adjusted without enlarging the optical pickup.