Nec Tokin Corporation

Tokin Corporation

Osamu Ito

Shigeyoshi Yoshida

Mitsuharu Sato

Norihiko Ono

Yutaka Shimada

Eishu Sugawara

A composite magnetic material is provided for use as an electromagnetic interference suppressing body for effectively suppressing an electromagnetic interference within a high frequency apparatus including a mobile communication terminal. The composite magnetic material consists essentially of a soft magnetic powder and an organic binder and is electrically non-conductive and has at least two magnetic resonances caused by at least two anisotropic magnetic fields (Hk). In the composite magnetic material, the anisotropic magnetic fields (Hk) are different in strength from each other.

Composite magnetic material and electromagnetic interference suppressor member using the same

An atomized mixture of flat soft magnetic powder and an organic binding agent is rolled by mutually confronting two rolling rolls so as to easily produce a composite magnetic sheet excellent in electromagnetic wave absorption characteristic. A plurality of the composite magnetic sheets are stacked by forming unevenness on joining surfaces thereof and rolled so as to realize a desired thickness. By sandwiching a mesh metal layer between the foregoing two composite magnetic sheets and joining them by applying rolling thereto, a mechanically strong electromagnetic interference suppressing sheet can be easily obtained. For reducing reflection and transmittance of electromagnetic waves of the composite magnetic sheet, embossing is applied to obverse and reverse surfaces thereof.

Method of producing a composite magnetic sheet

A mixture of flat soft magnetic powder and an organic binding agent is rolled by mutually confronting of rolls so as to produce a composite magnetic sheet excellent in electromagnetic wave absorption characteristic. A plurality of the composite magnetic sheets are stacked by forming groove surfaces on each of said plurality of sheets and rolled to a desired thickness. By sandwiching a conductive mesh metal layer between two of said composite magnetic sheets and joining them by applying rolling pressure thereto, a mechanically strong electromagnetic interference suppressing sheet can be easily obtained. In order to reduce reflection and transmittance of electromagnetic waves of the composite magnetic sheet, embossing is applied to obverse and reverse surfaces of the composite magnetic sheet.

Growing community of inventors

Akita, Japan

Osamu Ito