| 摘要 |
PURPOSE:To displace a reproducing element in follow-up to the up-and-down motion of the disk surface of an information recording medium disk by a constant needle pressure, by driving a vertical direction displacement driving coil by a signal corresponding to an inclination quantity of the surface of the information recording medium disk. CONSTITUTION:A signal corresponding to a surface deflection quantity of an information recording medium disk D, which has been outputted from a detector FD of the surface deflection quantity is amplified by an amplifier AMP for constituting a signal processing circuit SCC, and thereafter, delayed by a prescribed time in a delaying circuit DLC. Subsequently, in a phase compensating circuit PCC, a phase compensation of the whole system containing a mechanical system is performed, and therafter, said siganl is supplied to driving coils Cv1, Cv2 for vertical direction displacement through driving circuits DRC1, DRC2. In the driving coils Cv1, Cv2 for vertical direction displacement, a permanent magnet M is displaced in the vertical direction by each magnetic flux generated by said coil, and an electromagnetic force generated between each magnet pole of the permanent magnet M, so that a reproducing stylus S is pressed against the surface of the information recording medium disk D by a prescribed needle pressure. |
