BALANCE CORRECTION APPARATUS AND BALANCE CORRECTION METHOD

A balance correction apparatus is configured to correct weight imbalance around an axis of a spindle motor, and includes a piezoelectric actuator configured to apply an impact to a housing, a controller configured to generate as a rectangular wave a force profile that represents an acceleration applied to the housing by the piezoelectric actuator, and a waveform generator configured to generate a voltage waveform configured to drive the piezoelectric actuator, by integrating the force profile twice. The rectangular wave has a first acceleration after a leading edge and a second acceleration after a trailing edge. The first acceleration enables the disc to move relative to the spindle motor and the housing. The second acceleration enables the disc to move together with the spindle motor and the housing.