JPH04239107A - Electromagnetic interference preventive element - Google Patents

Abstract

PURPOSE:To reduce not only the needless signal of the basic frequency but also the needless signal of the low frequency band and high frequency band by using a conductor coil which is provided inside an insulating magnetic substance and has a resistant conductor whose resistance value is larger than those of conventional conductors. CONSTITUTION:An electromagnetic interference preventive element is one where a spiral conductor 5 consisting of a conductor pattern 6, a conductor pattern 7, and a middle conductor pattern 8 is buried in a rectangular parallelopiped 1, and the conductor patterns 6 and 7 are made of resistant conductive paste, and the conductor pattern 8 is made of paste such as Pd powder small in resistivity. The spiral conductor 5 of two patterns is a coil, and only the conductor patterns 6 and 7 are a composite element being the resistor. The external electrodes 9 and 10 at both ends of the rectangular parallelopiped 1 can also be provided after cutting of the end of the rectangular parallelopiped 1 and the end of the spiral conductor 5 and finely adjusting the resistance value.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic interference prevention element used as an electronic component of electronic equipment and the like.

0002

2. Description of the Related Art Conventionally, composite elements having an integral sintered structure in which a conductor coil is embedded in an insulating magnetic body have been put to practical use as electronic components for preventing electromagnetic interference. This type of composite device must be in the form of a small and thin chip so that it can be mounted on a wiring board. For this purpose, a conductive coil is formed inside an insulating magnetic body using a printed lamination method or a sheet lamination method, a magnetic laminate with such a conductive pattern is created, and this is fired to form an integrated structure. , it had a structure in which an external electrode was connected to the lead-out end of the conductive pattern. Conventionally, the conductor for such a conductive pattern has a relatively low resistance value, such as using an alloy of Ag75-50/Pd25-50 (wt%), a conductive paste consisting of a high melting point metal powder such as Pd, and a binder. A small conductor was selected.

0003

[Problems to be Solved by the Invention] Even if a conventional composite element in which a conductor coil made of a conductor with a low resistance is embedded is used as an electronic component for preventing electromagnetic interference in an electronic device, it is difficult to use it in the electronic device. It is only possible to reduce unnecessary signals in the fundamental frequency band in electrical signals that are transmitted.
It was not an excellent electromagnetic interference prevention element. The present invention has been made in view of the above-mentioned problems of the conventional technology, and its purpose is to widely eliminate unnecessary signals not only in the fundamental frequency band but also in the low frequency band and high frequency band. An object of the present invention is to provide an electromagnetic interference prevention element that can reduce electromagnetic interference.

0004

[Means for Solving the Problems] According to the present invention, in an electromagnetic interference prevention element having an insulating magnetic body and a conductor coil provided within the magnetic body, the conductor coil includes a resistive conductor. An electromagnetic interference prevention element characterized by this is obtained. Further, according to the present invention, there is obtained an electromagnetic interference prevention element characterized in that the conductor coil is entirely made of a resistive conductor. Further, according to the present invention, there is obtained an electromagnetic interference prevention element characterized in that a part of the conductor coil is made of a resistive conductor. That is, in the electromagnetic interference prevention element of the present invention, a conductor coil provided within an insulating magnetic body includes a resistive conductor having a higher resistance value than a conductor used in a conventional conductor coil. It is. In this case, the entire conductor coil may be made of such a resistive conductor, or a portion thereof may be made of such a resistive conductor. By doing so, an electromagnetic interference prevention element is formed in which an inductance element and a resistance element are provided in a composite manner on a single chip.

[0005]

[Function] When the electromagnetic interference prevention element of the present invention configured as described above is used as an electronic component of an electronic device, harmonics in the fundamental frequency band and low frequency band of unnecessary signals in the electrical signals used in the electronic device can be suppressed. The wave component is reduced by the above-mentioned resistance element part, and the harmonic component in the high frequency band is reduced by the above-mentioned inductance element part due to an increase in loss.

[0006]

[Example] In Figs. 1, 3 and 4, a rectangular parallelepiped 1 is made by pasting electrically insulating magnetic material (ferrite magnetic material) powder with a known binder and solvent to form a laminated plate, sheet, printed layer, etc. A magnetic laminate was created by proceeding with the process, and then fired to create an integrated structure. The electromagnetic interference prevention element of the first embodiment shown in FIG. 1 has a meandering conductor 2 embedded in the center of a rectangular parallelepiped 1. The meandering conductor 2 was formed from a paste of Ag/Pd alloy powder (hereinafter referred to as resistive conductive paste) having a high resistivity in the range indicated by the broken line in the Ag/Pd component ratio-resistivity diagram shown in FIG. It is a conductive pattern. The meandering conductor 2 is both a coil and a resistor. An inductance element with added resistance deteriorates in its characteristics as a coil, but as an electromagnetic interference prevention element it has excellent characteristics with large loss over a wide frequency range. Note that the resistive conductive paste is not limited to one containing only high-melting point metal powder with high resistivity. For example, the resistivity of the paste is adjusted by appropriately blending powder of a material with extremely high resistivity (such as zirconia or molybran oxide) that is used as a heating element in a high-temperature furnace and does not easily react with the ferrite magnetic material during firing. You can also do that. The composite element in FIG. 1 is made of a paste of insulating ferrite magnetic powder (hereinafter referred to as magnetic paste), and has a thickness approximately half that of the rectangular parallelepiped 1 (for example, 0.6 mm).
) is made using an extrusion molding method or a doctor blade method, and a meandering conductive pattern is printed on this magnetic sheet using a resistive conductive paste so that both ends are drawn out at the edges.
Furthermore, except for the meandering conductive pattern, the magnetic paste is printed to the same thickness (for example, about 0.04 mm) to form a printed layer of the same size as the magnetic sheet, and on top of this, another magnetic sheet is printed. are stacked together to form a magnetic laminate with a meandering conductive pattern in the center. After the laminate is fired and integrated, it has a chip-type structure in which width body-shaped external electrodes 3 and 4 are connected to both ends of the meandering conductor 2 and provided on both end faces of the rectangular parallelepiped 1. FIG. 3 shows a second embodiment of the electromagnetic interference prevention element of the present invention. That is, a spiral conductor 5 consisting of a lower conductive pattern 6, an upper conductive pattern 7, and three conductive patterns 8 in the middle is embedded in a rectangular parallelepiped 1. conductive pattern 6,
7 is made of a resistive conductive paste, and the conductive pattern 8 is made of a paste such as Pd powder with low resistivity (conductive paste).
It is a composite element in which the two-turn spiral conductor 5 is a coil, and only the conductive patterns 6 and 7 are resistors. The external electrodes 9 and 10 on both end faces of the rectangular parallelepiped 1 are connected to the ends of the rectangular parallelepiped 1 and the helical conductor 5, as shown by the chain lines.
It is also possible to install the resistor after cutting off the end of the resistor and finely adjusting the resistance value. In FIG. 4, a rectangular parallelepiped 1 includes a rectangular conductor 11
A third embodiment of the present invention is shown in which a third embodiment of the present invention is embedded. The orthogonal conductor 11 is made of non-magnetic nichrome (resistivity 100 μΩ・c
m). The rectangular parallelepiped 1 is placed at a relatively low temperature (for example, 10
This is the case for magnetic materials that can be fired at temperatures below 00°C), and a nichrome foil punched into a perpendicular conductor pattern is placed in the middle of a magnetic sheet, and magnetic paste is printed on both sides to the same thickness as the foil. A magnetic laminate was created by layering another magnetic sheet on top of the magnetic material, and then firing it. Note that it is desirable to safely form the orthogonal conductor 11 by spraying a ceramic coating layer onto the nichrome foil. Orthogonal conductor 11
is a composite element that is both a coil and a resistor.

[0007]

According to the electromagnetic interference prevention element of the present invention, by including a resistive conductor having a higher resistance value than conventionally used conductors in the conductor coil provided in the insulating magnetic body, The resistance value of the conductor coil can be set within a wide range. Therefore, when the conductor coil is formed entirely of a resistive conductor, the material used to form the resistive conductor depends on the selection, and when a part of the conductor coil is formed of a resistive conductor, the degree of The characteristics can be finely adjusted by including the resistive conductor up to that part. Therefore, it is possible to provide an excellent electromagnetic interference prevention element that can reduce unnecessary signals in a wide frequency band in electrical signals used in electronic devices.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a first embodiment of an electromagnetic interference prevention element of the present invention.

[Fig. 2] Ag used in the electromagnetic interference prevention element of the present invention.
FIG. 3 is a diagram showing the relationship between component ratio and resistivity for specifying the composition range of a Pd alloy.

FIG. 3 is a perspective view of a second embodiment and a third embodiment of the electromagnetic interference prevention element of the present invention.

FIG. 4 is a perspective view of a second embodiment and a third embodiment of the electromagnetic interference prevention element of the present invention.

[Explanation of symbols] 1 Rectangular parallelepiped 2 Meandering conductor 5 Spiral conductor 6 Conductive pattern 7 Conductive pattern 8 Conductive pattern 11 Direct conductor

Claims (3)

[Claims] 1. An electromagnetic interference prevention element comprising an insulating magnetic body and a conductor coil provided within the magnetic body, wherein the conductor coil includes a resistive conductor. 2. The electromagnetic interference prevention element according to claim 1, wherein the conductor coil is entirely made of a resistive conductor. 3. The electromagnetic interference prevention element according to claim 1, wherein a part of the conductor coil is made of a resistive conductor.