JPH0252408A - Lc composite part - Google Patents

Abstract

PURPOSE:To obtain a high performance part easily by forming an inductance between a pair of first electrodes according to cooperation of a conductor and a magnetic substance and forming a capacitance between the conductor and a second electrode whose dielectric consisting of a dielectric layer. CONSTITUTION:End surface conductors 18 and 20, which are connected to a conductor 14 respectively, are formed on both end surfaces of a magnetic substance 12 respectively. First electrode 22 and 24 formed on both ends of the magnetic substance 12 are connected to the end surface conductors 18 and 20. Therefore, an inductance is formed between the electrodes 22 and 24 by the cooperation of the conductor 14 and the magnetic substance 12. The value of this inductance is determined by the number of turns of the conductor 14 and the magnetic reluctance, etc. A second electrode 26 is formed on a dielectric layer 16 with a slight clearance therebetween. Thus, a capacitance is formed between the conductor 14, i.e., the electrodes 22 and 24, and the electrode 26 with the dielectric layer 16 being an interposed dielectric therebetween. The value of this capacitance is determined by the area of the electrode 26 facing the conductor 14, etc., ring in nature for various use.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to an LC composite component, in particular, it includes a magnetic material and a dielectric material, an inductance (L) is formed by the cooperation of the magnetic material and a conductor, and LC in which capacitance (C) is formed between a conductor and an electrode facing each other with a dielectric in between.
Regarding composite parts.

[Prior art] An example of this type of LC composite part is
This method is disclosed in Japanese Patent Application No. 25817 and Japanese Patent Application No. 63-33658. This first LC composite part is
A magnetic tube for inductance is formed by firing an extrusion molded product of a ferrite element, and a dielectric material layer is formed by electrophoresis. The second LC composite component is formed by joining a magnetic layer for inductance and a dielectric layer for capacitance in an unsintered state and then sintering them together.

[Problem to be solved by the invention]

In the above-mentioned LC composite component, capacitance is formed between the electrode placed on one side of the dielectric layer with the magnetic layer in between and the electrode placed on the other side of the dielectric, so ferrite is used. Both the tube and the magnetic layer had to have low resistivity, which required strict control of the firing atmosphere, temperature, etc. in addition to the composition. Therefore, it has been difficult to manufacture conventional LC composite parts. Also,
If the resistivity is made too small, the magnetic permeability of the magnetic material becomes small, resulting in a disadvantage that the filter characteristics in a high frequency region deteriorate.

Therefore, the main objective of the present invention is to provide an LC composite component that can be obtained more easily and with high performance.

[Means to solve the problem]

This invention includes a hollow or solid cylindrical magnetic body, a conductor spirally formed around the outer periphery of the magnetic body, a dielectric layer formed to cover the conductor, a dielectric layer formed at both ends of the magnetic body, a pair of first electrodes respectively connected to the ends of the conductor; and a second electrode disposed on the dielectric layer;
This is an LC composite component in which an inductance is formed between the electrodes by the cooperation of a conductor and a magnetic material, and a capacitance using a dielectric layer as a dielectric is formed between the conductor and the second electrode.

[Operation] Inductance is formed between the pair of first electrodes by the cooperation of the conductor and the magnetic material. In other words, since the outer periphery of the magnetic material is surrounded by a spiral conductor, the magnetic material becomes part of the magnetic circuit, similar to a coil with an iron core, and therefore An inductance is defined by the number of turns of the conductor, the permeability of the magnetic material, and its shape.

A capacitance is formed between the conductor and the second electrode using the dielectric layer as an intervening dielectric. That is, the conductor and the second
A capacitance is formed between the electrodes, which is assumed by the area of the conductor facing the second electrode, the distance therebetween, the dielectric constant of the dielectric layer, and the like.

[Effects of the Invention] According to the present invention, capacitance is formed between the conductor spirally formed around the outer periphery of the magnetic material and the second electrode facing across the dielectric layer formed around the outer periphery of the conductor. , it is not necessary to lower the resistivity of the magnetic material, and good filter characteristics can be obtained in the high frequency region. Therefore, according to the present invention, without very strict control over firing conditions,
An LC composite part with characteristics sufficient for practical use can be obtained.

The above objects, other objects, features and advantages of the present invention will become more apparent from the following detailed description of embodiments with reference to the drawings.

〔Example〕

FIG. 1 is an illustrative cross-sectional view showing one embodiment of the present invention.
FIG. 2 shows its external appearance. LCIJ assembly component 0
A spiral conductor 14 is formed around the outer periphery of the magnetic body 12, as partially indicated by a broken line in FIG. The conductor 14 turns from one end of the magnetic body 12 on the outer periphery of the magnetic body 12 at equal pitches and reaches the other end.

The surface of the magnetic body 12 on which the conductor 14 is formed is the dielectric layer 1
Covered by 6. Further, a conductor 1 is provided on both end surfaces of the magnetic body 12.
End surface conductors 18 and 20 are formed, respectively, to be connected to 4. The end conductors 18 and 20 are provided with first electrodes 22 and 2 formed at both ends of the magnetic body 12.
4 is connected.

Therefore, between the two first electrodes 22 and 24,
The cooperation of the conductor 14 and the magnetic body 12 forms an inductance. The value of inductance is determined by the number of turns of the conductor 14, magnetic resistance, that is, the length of the magnetic body 12, magnetic permeability, cross-sectional area, etc.

A second electrode 2 is placed on the dielectric layer 16 while maintaining insulation from the first electrodes 22 and 24, that is, with a slight gap.
6 is formed. Therefore, a capacitance is formed between the conductor 14, that is, the first electrodes 22 and 24, and the second electric field jTi26, using the dielectric N16 as an intervening dielectric. The value of the capacitance is determined by the second
It is determined by the area of the electrode 26, the gap between the conductor 14 and the second electrode 26, the dielectric constant of the dielectric layer 16, etc.

Such an LC composite component 10 is formed, for example, as follows. First, a cylindrical molded body to become the magnetic body 12 is made of, for example, 0.17Nio-0,3ZnO-
It is made of a ceramic material of 0.05CuO-0.48Fe203 and is formed by extrusion molding. Thereafter, a conductive paste to become the conductor 14 is printed on the outer periphery of the molded body by an offset method, and the same conductive paste to become the end face conductors 18 and 20 is applied to the end face of the molded body by a dip method. This conductive paste has a Pd to Ag ratio of 3.
The main component is metal powder consisting of 7.

After printing the conductive paste, the sheet molded body to become the dielectric material 16 is wound several times over the molded material to become the magnetic material 12. The sheet molded body is made of, for example, 0.7Pb (Fe
zz:+Wl/F ) 03 0.3PbTio, a ceramic material formed by the doctor blade method.

The sheet molded body is pressure-bonded to the molded body to become the magnetic body 12 by the CIP method. Next, it is placed in a firing furnace and fired in the atmosphere at a temperature of 1000°C for 2 hours.

When the firing is completed, the molded body, the conductor paste, and the sheet molded body each become magnetic material 12. This results in a conductor 14 and a dielectric layer 16.

Thereafter, the first electrodes 22 and 24 and the second electrode 26
An electrode paste to be used is printed on both ends of the magnetic material 12 and a desired portion of the dielectric layer 16 by the Dip method and the offset method. This electrode paste consists of Pd and Ag.
The main component is metal powder with a ratio of 1:9, and also contains glass frit. The electrode paste for the first electrodes 22 and 24 and the second electrode 26 is
Baked for 30 minutes at a temperature of 0°C. In this way, the electrode paste is applied to the first electrode 22 as shown in FIG.
and 24 and the second electrode 26, and the LC composite component 10 is completed.

In addition, instead of electrodes made of such electrode paste,
A first electrode made of a metal cap and a second electrode made of a metal shaft.
Electrodes and the like may also be used.

The following table shows the measurement results of insertion loss when the second electrode 26 of the LC composite component 10 is grounded and the first electrodes 22 and 24 are used as input/output terminals to form a distributed constant low-pass filter.

In the table, 12 is a magnetic material, 14 is a conductor, 16 is a dielectric layer, 22 and 24 are first electrodes, and 26 is a second electrode.

Patent Applicant: Murata Manufacturing Co., Ltd. Agent: Patent Attorney: Yama 1) As is clear from the table above, this LC composite component 10:
It can be seen that a large insertion loss is obtained in the high frequency region, and it functions as a good high frequency filter.

Note that in order to reduce stray capacitance between lines, care must be taken not to make the spacing between the spiral conductors 14 too narrow.

[Brief explanation of the drawing]

FIG. 1 is an illustrative cross-sectional view showing one embodiment of the present invention. FIG. 2 is an external view of the embodiment shown in FIG.

Claims (1)

[Scope of Claims] 1. A hollow or solid cylindrical magnetic body, a conductor spirally formed around the outer periphery of the magnetic body, a dielectric layer formed to cover the conductor, and a dielectric layer formed to cover the magnetic body. A pair of first electrodes formed at both ends and connected to the ends of the conductor, respectively, and a second electrode disposed on the dielectric layer, and between the pair of first electrodes, the An LC composite component, wherein an inductance is formed by cooperation between a conductor and the magnetic material, and a capacitance using the dielectric layer as a dielectric is formed between the conductor and the second electrode.