Patent ID: 7304915

Claim:
An actuator of an optical disk system, including a light source, recording and/or reproducing information from an optical disk surface, the actuator comprising: an inner focusing coil located near an inner boundary of the optical disk surface; an outer focusing coil located near an outer boundary of the optical disk surface; a first signal wire connected to a first port of the inner focusing coil, which transmits an inner coil signal; a second signal wire connected to a first port of the outer focusing coil, which transmits an outer coil signal; and a common signal wire connected to a second port of the inner focusing coil and a second port of the outer focusing coil, which transmits a common reference signal, wherein the inner coil signal is a sum of first and second signals, and the outer coil signal is a difference of the first and second signals and wherein the common reference signal has a same magnitude and an opposite polarity as the first signal.