Patent ID: 7631322

Claim:
A magnetic circuit, comprising: a plurality of focus coil units; and a magnet comprising a plurality of magnet portions to interact with the plurality of focus coil units, each magnet portion being polarized in a direction opposite to an adjacent magnet portion, of the plurality of magnet portions, wherein electromagnetic forces act on at least two focus coils, of at least one of the plurality of focus coil units, in respectively same directions in response to focus driving signals and in respectively opposite directions in response to tilt driving signals, wherein the at least two focus coils have different effective coil lengths, wherein each of the plurality of focus coil units comprise a first focus coil unit, comprising at least two focus coils, and a second focus coil unit, comprising at least two focus coils, and wherein a focus coil of the first focus coil unit, having a longer effective coil length than another focus coil of the first focus coil unit, is connected with a focus coil of the second focus coil unit, having a shorter effective coil length than another focus coil of the second focus coil unit.