Abstract: An objective lens drive unit including a bobbin wound with driving coils and having mounted thereon a lens for transmitting a light beam which is controlled by drive currents flowing through the coils is used for controlling the focussing/tracking of the light beam on a recording medium. The bobbin comprises a hole mounting the objective lens, first recesses formed in opposed side walls of the bobbin substantially in parallel with the mounting hole for accommodating one of the coils wound substantially perpendicularly to the mounting hole, notches formed in the first recesses parallel with the mounting hole for accommodating passing terminal end/start portions of the coil, and second recesses formed along two opposed sides of the opposite side walls for accommodating the other coils wound so as to intersect each other at the other pair of opposite side walls of the bobbin.

Abstract: An apparatus for electromagnetically driving an objective in conformance with movements of an optical disc in the vertical direction and deviations from track possibly produced in rotation of the disc, to thereby accomplish an automatic focussing of a write and/or read light beam on the disc. A driven unit including the objective lens system is supported by closely wound coil springs for suppressing unwanted resonance which will otherwise be produced in the driving operation. The apparatus is effective for controlling the focussed position of the light beam both in recording and reproducing modes. The spring coils are integrally mounted on a stationary mounting member by molding.

Abstract: In an objective lens drive apparatus for driving a body to be driven including an objective lenses in the focusing direction along the optical axis and in the tracking direction perpendicular to the optical axis, there is provided an adjuster for allowing the center of a driving force exerted on the body in the tracking direction to coincide with the center of gravity of the body or to shift the center of gravity farther away from the objective lenses from the driving force along the optical axis of the objective lenses.