Patent ID: 8356519
Filing Date: 2013-01-22
Classification: B06B,G01H,G01N

Abstract:
1. A transducer comprising: a multi-loop coil including two or more looped coil portions that are connected to each other, wherein the looped coil portions are located on top of a rod member, and the looped coil portions form magnetic fields on the surface of the rod member in a direction parallel to the lengthwise direction of the rod member; and one or more magnets that are arranged to form a static magnetic field on the surface of the rod member, whereon the surface of the rod member a dynamic magnetic field is formed by the multi-loop coils in the direction parallel to the lengthwise direction of the rod member, even partially in a direction parallel to the lengthwise direction of the rod member, wherein the rod member is formed of a conductor, an eddy current flowing on the surface of the rod member in a circumferential direction of the rod member is generated by adjusting currents flowing in the multi-loop coils, a force is applied to the rod member in a direction perpendicular to the lengthwise direction of the rod member due to the static magnetic field formed by the eddy current and the static magnetic field, when a wave vibrating in a direction perpendicular to the lengthwise direction of the rod member is transmitted along the rod member, an eddy current is generated in the circumferential direction of the rod member under the static magnetic field, and an electromotive force is formed in the multi-loop coil to form a magnetic field in a direction that is opposite to the direction in which a magnetic field formed by the eddy current is formed, to offset the magnetic field formed by the eddy current, and a vibration transmitted to the rod member is detected by detecting the electromotive force.