Compact optical disk drive unit

An drive unit for an optical information recording medium comprising:

• an objective lens for converging light emitted from a light source and irradiating the converged light to an optical information recording medium:
• a focusing magnetic circuit for holding the objective lens and driving the objective lens in a direction of an optical axis of the objective lens;
• a carriage for supporting elastically said objective lens and at least a moving part of said focusing magnetic circuit;
• and
• a seeking magnetic circuit arranged outside the carriage for performing a seeking operation, said seeking magnetic circuit having a magnet, a yoke and a movable coil, said magnet and said yoke extending respectively along a radial direction of said optical information recording medium, and said movable coil surrounding the yoke without contacting it and being fixed to said carriage,
• said movable coil being formed in a polygonal shape in a cross section perpendicular to said radial direction of said optical information recording medium, one side of the movable coil facing the carriage being located below the moving part of the focusing magnetic circuit and being shorter with respect to the direction of the optical axis than the opposite side of the movable coil so as to provide a partial recess for the moving part of said focusing magnetic circuit.