Patent ID: 8664914

Claim:
A battery charger designed to be used with a battery built-in device having an electromagnetically coupled induction coil incorporated in the battery built-in device and a battery rechargeable with a power induced by the induction coil, the battery charger comprising: a casing having a top plate; a primary coil connected to an AC power source for inducing electromotive force to the induction coil, the primary coil being separated from the battery built-in device by the top plate; a movement mechanism for moving the primary coil along an inner surface of the top plate; and a position detection controller for detecting a position of the battery built-in device, the position detection controller controlling the movement mechanism to move the primary coil closer to the induction coil contained in the battery built-in device, wherein the casing houses the primary coil, the movement mechanism, and the position detection controller.