Tokin Corporation

Nec Tokin Corporation

Mitsuharu Sato

Shigeyoshi Yoshida

Norihiko Ono

Koji Kamei

Osamu Ito

Yutaka Shimada

Tadakuni Sato

Eishu Sugawara

Toshihisa Inabe

Hitoshi Togawa

Naoharu Yamamoto

Makoto Teshima

Yoshihiko Kato

Yukio Hotta

A coil antenna is disclosed comprising a magnetic core and a wire wound around the magnetic core. The magnetic core is made of a mixture comprising soft magnetic powder and an organic binder agent. The magnetic core has a specific complex permeability whose real part &#x3bc;' is 20 or more over a frequency range of 10 MHz or less and whose imaginary part &#x3bc;&#x2033; is 10 or more over a frequency range of 10 MHz or more so that the magnetic core is also servable as a noise suppressor against high-frequency noise.

Coil antenna

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

In a composite magnetic body comprising soft magnetic powder dispersed in an organic binding agent and having an electromagnetic interference suppressing effect, powder excellent in thermal conductivity is further dispersed into the organic binding agent so as to provide a composite magnetic body excellent in thermal conductivity. This composite magnetic body may also be used as a heat dissipation sheet for an electronic device. Further, it may also constitute a heat sink having an electromagnetic interference suppressing effect. As the organic binding agent, thermoplastic polyimide or liquid crystal polymer can be cited. As the powder excellent in thermal conductivity, AlO, AlN, cubic BN, insulating SiC or a heat conductive reinforcement (capton) can be cited.

Highly heat-conductive composite magnetic material

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

There is provided a composite magnetic tape which can be easily applied irrespective of the inside or outside of an electronic equipment, prevent radiation of undesired electromagnetic waves from the inside of the equipment and reflection into the inside of the equipment, and shield electromagnetic noise from the outside of the equipment. The tape may be in the form of an adhesive tape or a self-welding tape. The tape is constituted of a composite magnetic layer formed by dispersing soft magnetic powder into an organic binding agent. Alternatively, it may have a stacked structure of a composite magnetic layer and a conductor layer.

Composite magnetic tape

An electromagnetic interference suppressing body is provided for suppressing electromagnetic interference by undesirable electromagnetic waves. The body includes a conductive support element and a non-conductive soft magnetic layer provided on at least one surface. The electromagnetic interference suppressing body may be used in an electronic equipment comprising a circuit board and an active element mounted on the circuit board, and is interposed between the circuit board and the active element so as to suppress the interference by an induction noise generated from the active element. The electromagnetic interference suppressing body may also be used in a hybrid integrated circuit element having an active element and a passive element mounted on a circuit board. The hybrid integrated circuit element is covered with and sealed by a non-conductive layer and the electromagnetic interference suppressing body overlying an outer surface of the non-conductive layer.

Electromagnetic interference suppressing body having low electromagnetic transparency and reflection, and electronic device having the same

A tube for externally covering or bundling electric cables is provided for suppressing radiation of undesired electromagnetic waves. The tube is made of a material in which soft magnetic powder is mixed with and dispersed into an organic binding agent. For protecting the cable from the undesired electromagnetic waves from the exterior, it is preferable to provide a conductor layer at an outer side of a composite magnetic layer. For facilitating mounting onto the cable, the tube is provided with a slit in a longitudinal direction. Alternatively, the cable may have a spiral structure. As an organic binding agent, it is preferable to use an elastomer which is excellent in extensible property. Further, it is preferable that the soft magnetic powder is powder being essentially flat.

Composite magnetic tube and method of producing the same, and electromagnetic interference suppressing tube

For improving a noise characteristic of a printed circuit board excellent in noise characteristic, a magnetic prepreg formed by impregnating a magnetic paint composed of soft magnetic powder and thermosetting resin into a glass cloth is used as a prepreg constituting the printed circuit board. It is preferable that the soft magnetic powder is metal powder being essentially flat. Further, it is preferable that a main component of the thermosetting resin is epoxy resin.

Magnetic prepreg, its manufacturing method and printed wiring board employing the prepreg

An EMI countermeasure component is provided relative to an active element, which does not deteriorate a circuit function of the active element, but has a sufficient shielding effect against permeation of electromagnetic waves radiated to the exterior, and further suppresses a malfunction or the like due to mutual interferences between peripheral components or an electromagnetic induction to a signal line. The EMI countermeasure component is made of a composite magnetic body including soft magnetic powder having oxide films on the surfaces thereof and an organic binding agent, and extinguishes undesired high frequency electromagnetic radiation as heat due to its complex permeability.

EMI preventive part and active device with the same

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.

Method of manufacturing composite magnetic sheet

Compound magnetic material and electromagnetic interference suppressor

An electromagnetic interference suppressing body is provided for suppressing electromagnetic interference by undesirable electromagnetic waves. The body can have a conductive support element and a non-conductive soft magnetic layer provided on at least one surface. The electromagnetic interference suppressing body may be used in circuit board electronic equipment and in a hybrid integrated circuit element having an active element and a passive element mounted on a circuit board.

Electronic device having the electromagnetic interference suppressing

A composite magnetic article for use as an electromagnetic interference suppressing body, which comprises soft magnetic powder of at least one soft magnetic composition having a magnetostriction constant, each of particles of the powder being flaky, and organic binding agent binding said soft magnetic powder dispersed therein. The soft magnetic powder is as annealed after being worked flaky. The flaky particles of the soft magnetic powder have an average thickness less than a skin depth within which the skin effect occurs at a frequency band for which said composite magnetic article is used, each having an oxide outer layers.

Growing community of inventors

Yokohama, Japan

Mitsuharu Sato