Patent ID: 8064299

Claim:
An optical pick-up of an optical disc unit of irradiating a laser light to an optical disc thereby recording and reproducing information signals including; a plurality of laser light sources each generating a laser light in the direction of a linear velocity parallel to the disc surface of the optical disc, a plurality of total reflection mirrors each irradiated with a laser light generated by each of the plurality of laser light sources and reflecting the light in a direction perpendicular to the disc surface of the optical disc, and an objective lens driving device having a plurality of objective lenses each supplied with each of the laser lights reflected by each of the plurality of total reflection mirrors and irradiates the laser light to the optical disc in which the objective lens driving device includes: a plurality of objective lenses for condensing the laser light to the optical disc, first and second tracking coils that supply varying magnetic fields for controlling the radial position of the objective lens to the surface of the optical disc, a focusing coil that supplies the varying magnetic fields for controlling the position of the objective lens perpendicular to the surface of the optical disc, a lens coil holder in which the plurality of objective lenses are mounted being juxtaposed in the radial direction of the optical disc on the surface opposing to the optical disc, and the first and second tracking coils are mounted on the lateral surface parallel to the radial direction of the optical disc, and having a focusing coil at the periphery thereof, first and second magnet groups which are arranged in the radial direction to the optical disc and generate DC magnetic fields for driving the lens coil holder in the radial direction to the surface of the optical disc and in the direction perpendicular to the surface of the optical disc, and suspension wires which are provided in the direction of the linear velocity parallel to the surface of the optical disc for supplying control signals to the first and the second tracking coils and the focusing coil thereby generating the varying magnetic fields and supporting the lens coil holder, in which the lens coil holder has a cavity extending in the radial direction of the optical disc for irradiating the laser light to the total reflection mirror, the first tracking coil is situated on the lateral surface of the lens coil holder above the cavity and the second tracking coil is situated on the lateral surface of the lens coil holder opposite to that of the first tracking coil with reference to the total reflection mirror interposed therebetween, and the first tracking coil and the second tracking coil are situated at different heights with reference to the vertical center of the suspension wires interposed therebetween.