Murata Manufacturing Co., Ltd.

Tetsuo Hatakenaka

Tetsuya Morinaga

Masahiro Bando

Takaomi Toi

Koki Sasaki

Kazuo Kasahara

Takayuki Hirotsuji

Toshimi Kaneko

An electronic device such as a chip coil including an electric wire firmly connected to electrodes in a highly reliable fashion is constructed to be mounted on a printed circuit board or substrate in a stable and reliable manner. At both ends of a core of the chip coil, there are provided electrodes having a multilayer structure including a high-conductivity layer made of Ag, Ag&mdash;Pd, or a similar material; a solder barrier layer made of Ni; and an easy-soldering layer made of Sn or solder. End portions of the electric wire are embedded in the easy-soldering layer so that the resultant electrode structure has a substantially flat surface. A thermo-compression process is performed so that the end portions of the electric wire are connected to the solder barrier layer via solid welding and to the easy-soldering layer via brazing.

Electronic device having electric wires and method of producing same

An electronic device such as a chip coil including an electric wire firmly connected to electrodes in a highly reliable fashion is constructed to be mounted on a printed circuit board or substrate in a stable and reliable manner. At both ends of a core of the chip coil, there are provided electrodes having a multilayer structure including a high-conductivity layer made of Ag, Ag--Pd, or a similar material; a solder barrier layer made of Ni; and an easy-soldering layer made of Sn or solder. End portions of the electric wire are embedded in the easy-soldering layer so that the resultant electrode structure has a substantially flat surface. A thermo-compression process is performed so that the end portions of the electric wire are connected to the solder barrier layer via solid welding and to the easy-soldering layer via brazing.

A method for accurately and inexpensively producing a chip-type coil device comprises first forming an insulating plate. A plurality of parallel division grooves are then formed in a first direction on the insulating plate on one surface thereof. Thereafter, a conductive layer is formed on the insulating plate, wherein the conductive layer also coats the division grooves. The process then entails forming recess grooves between the division grooves on the insulating plate on which the conductive layer has been formed, and then dividing the insulating plate by forming slots within the division grooves, wherein the slots have widths which are smaller than widths of the division grooves. The method then entails dividing the insulating plate in a second direction to form a plurality of cores, wherein each of the cores comprise at least two leg portions having a first recess therebetween formed by one of the first recess grooves, and further including terminal electrodes on the leg portions formed by the conductive layer. Thereafter, for each of the cores, winding wire is wound around a winding section of the core and the wire is connected to terminal electrodes on the leg portions. The method provides devices which have improved accuracy and strength compared to the conventional devices produced by press molding.

Chip-type coil device

Method of producing coil devices

A chip coil wherein the coil wound around the core is enclosed with a sleeve core. The upper surfaces of the core and the sleeve core are ground so as to adjust the inductance of the chip coil.

Growing community of inventors

Takefu, Japan

Tetsuo Hatakenaka