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AssigneeHitachi, Ltd.
InventorsTadashi Fujieda, Shinzou Ikeda, Sai Ogawa, Teruyoshi Abe, Yasuhisa Aono
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An object of the present invention is to provide an electromagnetic wave absorber which is excellent in the electromagnetic wave absorbing characteristics in the high frequency range above 1 GHz, and to provide a method of manufacturing the electromagnetic wave absorber and appliances using the electromagnetic wave absorber. An electromagnetic wave absorber and a composite member in accordance with the present invention are characterized by that magnetic metal grains are covered with ceramic above 20 volume %. Further, a method of manufacturing the electromagnetic absorber and the composite member is characterized by that composite magnetic particles, in which a plurality of magnetic metal grains and ceramic are unified, are formed through the mechanical alloying method of a composite powder composed of magnetic metal powder and ceramic powder. Further, the present invention exists in a semiconductor device, an optical sending module, an optical receiving module, an optical sending and receiving module, an automatic tollgate preventing erroneous operation due to electromagnetic wave disturbance which use the electromagnetic wave absorber.
An electromagnetic wave absorber comprising composite magnetic particles having a grain size smaller than 10 μm in which magnetic metal grains and ceramic are unified.
An electromagnetic wave absorber comprising composite magnetic particles in which a plurality of fine magnetic metal grains and ceramic are unified by enclosing said plurality of fine magnetic metal grains with said ceramic.
An electromagnetic wave absorber comprising composite magnetic particles in which magnetic metal grains and a plurality of ceramic grains are unified by embedding the ceramic grains into the magnetic metal grains.
A method of manufacturing an electromagnetic wave absorber, wherein composite magnetic particles, in which magnetic metal grains and ceramic are unified, are formed through a mechanical alloying method of a magnetic metal powder and a ceramic powder.
A method of manufacturing an electromagnetic wave absorber, wherein composite magnetic particles, in which magnetic metal grains and ceramic are mixed and unified, are formed by a mechanical alloying method of a composite powder containing a magnetic metal powder and a ceramic powder using metallic balls or ceramic balls, size of said ball being larger than grain size of the metallic powder, a volumetric amount of said balls being larger than a volumetric amount of said composite powder.
A composite member comprising composite magnetic particles in which magnetic metal particles and ceramic are unified.
A composite member formed by compounding composite magnetic particles, in which magnetic metal grains and ceramics are unified, and a material having an electric resistivity higher than an electric resistivity of the composite magnetic particle.
A electromagnetic wave absorber formed by compounding composite magnetic particles, in which magnetic metal grains and ceramics are unified, and at least one kind of material selected from the group consisting of a resin having an electric resistivity higher than an electric resistivity of the composite magnetic particle alumina and silica.
A semiconductor device in which a semiconductor element mounted on a printed wiring board is sealed with a resin containing an electromagnetic wave absorber, wherein said resin in the side of said element is covered with a resin free from said electromagnetic wave absorber.
A printed wiring board comprising a wiring circuit on an insulation board, and said circuit is covered with an insulation layer, wherein layers comprising an electromagnetic wave absorber are formed on a surface of said insulation board opposite to the surface having said wiring circuit formed and on said insulation layer.
A semiconductor device, wherein a semiconductor element mounted on a printed wiring board is covered with a metal cap of which an inner peripheral surface is formed of an electromagnetic wave absorber.
A semiconductor device, wherein a semiconductor element mounted on a printed wiring board is covered with a cap having an electromagnetic wave absorber.
A semiconductor device, wherein a printed wiring board and a semiconductor element mounted on said board are covered with a casing having an electromagnetic wave absorber.
A semiconductor device, wherein a printed wiring board and a semiconductor element mounted on said board are covered with a metal casing of which an inner peripheral surface is formed of an electromagnetic wave absorber.
An optical sending or receiving module comprising at least one of a light emitting element and a light receiving element;
An optical sending or receiving module comprising at least one of a light emitting element and a light receiving element;
An optical sending or receiving module comprising at least one of a light emitting element and a light receiving element;
An automatic tollgate comprising a tollgate roof;
An automatic tollgate comprising a tollgate roof;
An electronic device, wherein an electronic element mounted on a printed wiring board is sealed with a resin containing an electromagnetic wave absorber.
A printed wiring board comprising a wiring circuit on an insulation board, wherein a layer having an electromagnetic wave absorber is formed on at least one of a surface of said insulation board having said wiring circuit and on a surface opposite to said surface having said wiring circuit.
An electronic equipment casing, wherein an electromagnetic wave absorber is formed on an inner peripheral surface of a metal casing having an opeing portion.
An automatic tollgate comprising a tollgate roof;
Dependencies are inferred from the claim text.