Abstract: The present invention relates to a PM (Pulse-Width Modulation) type step motor used for conveying an optical pickup lens of media devices or a mobile camera lens. In detail, the present invention relates to a step motor that is composed of a stator, a rotor rotating by interacting with the stator, a lead screw combined with the rotor and rotating with the rotation of the rotor, and a bearing supporting the lead screw and which can perform precise conveying because it can perform fine adjustment and of which the operation state can be precisely sensed by having a position correcting unit that moves the lead screw to a desired position by finely moving it while contracting and stretching and a rotation sensing unit that is disposed at a side of the rotor or a rotary member rotating with the rotor and senses rotation of the rotor.

Abstract: Disclosed herein is a vibration generator which is used to embody vibration for signal reception indication or a haptic function of wireless communication devices such as mobile phones. The vibration generator includes a casing which has a space therein, a stator which is provided in the casing and is provided with a coil along which current flows, a vibrator which is provided in the casing and is horizontally moved by electromagnetic force, an elastic body which is fixed at a first end thereof to the casing and fixed at a second end thereof to the vibrator, and a residual vibration reducer which is provided between the vibrator and the casing to absorb vibration of the vibrator. Therefore, after the vibration of the vibrator is stopped, the time it takes to stop movement of the vibrator can be markedly reduced.