Seoul National University

Woo-Chul Kim

Yoon-young Kim

Seung-Hyun Cho

Chan-Il Park

Provided are a microspeaker and a method of designing the same. The microspeaker includes a first permanent magnet and a second permanent magnet disposed on the first permanent magnet with a predetermined gap therebetween, the first and second permanent magnets having opposite magnetization directions; a third permanent magnet and a fourth permanent magnet disposed on the third permanent magnet with a predetermined gap therebetween, the third and fourth permanent magnets being disposed next to the first and second permanent magnets, respectively, with an air gap therebetween; a yoke interposed between the first and second permanent magnets and between the third and fourth permanent magnets; a voice coil inserted into the air gap; and a vibrating diaphragm attached to an end of the voice coil and forming a sound field according to the movement of the voice coil, wherein the first and third permanent magnets have opposite magnetization directions, and the second and fourth permanent magnets have opposite magnetization directions.

Microspeaker and method of designing the same

A magnetostrictive transducer generating a torsional wave in a subject having a predetermined section and measuring a torsional wave propagating in the subject. In the magnetostrictive transducer having a ferromagnetic patch attached to a predetermined position of a subject, a cylindrical insulator installed around the periphery of the ferromagnetic patch, and a coil wound around the cylindrical surface of the insulator, a torsional wave is generated based on a magnetostrictive effect to then be induced to the subject when current is applied to the coil. The ferromagnetic patch includes a strip unit attached to the subject in an inclined manner with respect to an axial direction of the subject and transferring the torsional wave to the subject; and tail units formed at opposite ends of the strip unit and concentrating a magnetic flux on the strip unit when current is applied to the coil.

Growing community of inventors

Suwon-si, South Korea

Woo-Chul Kim