JPH0946157A - Noise filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve connection reliability and noise characteristic by arranging a signal line conductor pattern between plural dielectric layers and arranging a ground line conductor pattern respectively adjacent layers. SOLUTION: Linear or meandering signal line conductor patterns 2,... are formed between dielectric layers 1a, 1b, between dielectric layers 1c, 1d, and between dielectric layers 1e, 1f of a laminator consisting of 6-layer of dielectric layers 1a-1f including upper/lower margin layers 1a, 1f. Furthermore, linear or meandering ground line conductor patterns 3a, 3b opposite to the signal line conductor patterns 2,... are formed between the dielectric layers 1b, 1c and between the dielectric layers 1d, 1e. Then input output terminal electrodes of the signal side are connected directly to the extended part of the signal line conductor patterns 2,... to connect the plural signal line conductor patterns 2,... in parallel with the signal side input output terminal electrodes.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a noise filter in which a linear or meandering signal line conductor pattern and a ground line conductor pattern facing the signal line conductor pattern are arranged in a laminate in which a plurality of dielectric layers are laminated. It is about.

[0002]

2. Description of the Related Art Conventionally, a structure in which a signal side coil and a ground side coil are formed in a laminated body in which a plurality of dielectric layers are laminated, and a signal line conductor pattern of about one turn pattern is formed between the first dielectric layers. Then, one end thereof is connected to the other end of the signal line conductor pattern formed between different first dielectric layers by a via hole conductor penetrating the dielectric layer, and is opposed to the signal line conductor pattern between the second dielectric layers. A ground line conductor pattern is formed and one end thereof is connected to the other end of the ground line conductor pattern formed between different second dielectric layers by a via hole conductor penetrating the dielectric layer.

In addition, as another structure, half-patterned signal line conductor patterns and ground line conductor patterns are arranged in parallel between the respective dielectric layers, and the signal line conductor pattern and ground line conductor are provided between the layers adjacent to each other. A semi-patterned ground line conductor pattern and signal line conductor pattern are arranged in parallel so as to face the pattern, and both signal line conductor patterns are connected by a via-hole conductor penetrating the dielectric layer. They were connected by via-hole conductors that penetrate the layers.

In any structure, when forming a signal side coil composed of a plurality of signal line conductor patterns and a ground side coil composed of a plurality of ground line conductor patterns, a via hole conductor penetrating the thickness of the dielectric layer is used. Since the connection is made, the connection reliability is lowered, the manufacturing process is complicated, and the cost cannot be reduced.

On the other hand, as disclosed in Japanese Patent Application Laid-Open No. 4-271610, in a laminated body made of magnetic material,
A noise filter has already been known by forming a linear or meandering signal line conductor pattern and a ground line conductor pattern. In the above noise filter, both ends of the signal line conductor pattern directly extend to the end faces in the longitudinal direction of the laminate, and the signal side terminal electrodes are formed at the end face extension portions. One end of the pattern extends directly to the end face in the width direction or the end face in the longitudinal direction of the laminate, and the ground-side terminal electrode is formed at the end face extension portion.

Therefore, compared with the above noise filter, there is no need to use a via-hole conductor, the manufacturing process is simplified, and the connection reliability with the terminal electrode is improved.

[0007]

However, Japanese Patent Laid-Open Publication No.
In the noise filter of No. 71610, since the laminated body is mainly composed of a magnetic material, even if the inductance component of the signal line conductor pattern and the ground line conductor pattern can be secured, a sufficient capacitance component between both conductor patterns can be obtained. There was a problem that I could not.

At the same time, the signal line conductor pattern and the ground line conductor pattern are substantially the same pattern, and in order to allow the current generated in the ground line conductor pattern to flow down to the ground potential, it is necessary to use the ground through a considerably long conductor. Since it flows to the side terminal electrode, a sufficient return effect cannot be obtained, and this capacitance component cannot be obtained sufficiently, and since a sufficient return effect cannot be obtained, a sufficient noise attenuation effect can be obtained on the high frequency side of the frequency. There was a problem that I could not.

It is also disclosed at the same time to interpose a dielectric material only in the portion where the capacitance is generated, but as a practical matter, it is very difficult to replace a part of the magnetic material with the dielectric material. It is difficult, for example, with a magnetic sheet,
Even if the dielectric sheets are laminated and integrally fired, the firing behavior is different, so that peeling occurs between the two sheets.

The present invention has been devised in view of the above problems, and an object thereof is to improve connection reliability for the construction of a coil and to improve noise characteristics on the high frequency side. The purpose is to provide a noise filter.

[0011]

In order to solve the above-mentioned problems, the present invention provides a first dielectric layer formed by stacking a plurality of dielectric layers, a second dielectric layer, and a second dielectric layer. A laminated body having dielectric layers, and a linear or meandering signal line conductor pattern arranged between the first dielectric layers of the laminated body and having ends extending at both ends in the longitudinal direction of the laminated body. A first ground line that is disposed between the second dielectric layers of the laminated body, has one end extending to the end face in the width direction of the laminated body, and faces a part of the signal line conductor pattern. A second conductor layer is disposed between the conductor pattern and the second dielectric layer of the laminated body, and has one end extending to an end face in the width direction of the laminated body and facing a part of the signal line conductor pattern. Ground line conductor pattern and longitudinal direction of the laminate A signal-side terminal electrode formed on both end faces and connected to both ends of the signal line conductor pattern, and formed on an end face in the width direction of the laminate, and connected to one end of the first and second ground line conductor patterns. And a plurality of signal line conductor patterns are connected to each other via a signal side terminal electrode to form a signal side coil, and a plurality of first and second ground line conductor patterns are provided. It is a noise filter in which two ground-side coils are formed by connecting them via ground-side terminal electrodes.

[0012]

According to the present invention, since the laminated body is mainly composed of the dielectric material, a sufficient capacitance component between the signal side coil and the ground side coil can be obtained. Further, the reduction of the inductance component in each coil due to the use of the dielectric material is compensated by making the signal line conductor pattern and the ground line conductor pattern meandering, or by using a plurality of patterns. A plurality of signal line conductor patterns for composing the signal side coil and a plurality of ground line conductor patterns for composing the ground side coil are directly connected to each terminal electrode formed on the end face of the laminated body. Has been done. Therefore, unlike the conventional case, the plurality of conductor patterns are not connected via the via-hole conductors, so that the connection reliability is improved.

As described above, since the sufficient capacitance characteristic and the sufficient inductance value are obtained, the characteristics of the noise filter can be satisfied.

Furthermore, since the ground line conductor pattern arranged between one layer is divided into two and each is directly connected to the ground side terminal electrode, the impedance of the ground line conductor pattern can be reduced. As a result, the difference between the input / output impedance of the insertion circuit and the impedance of the filter can be immediately returned to the ground side terminal electrode through the divided ground line conductor pattern, so that the attenuation characteristic is particularly excellent in the high frequency region. Become.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings. FIG. 1 is an external perspective view of the noise filter of the present invention.
FIG. 4 is an exploded perspective view of a laminated body portion.

In the figure, 1 is a laminated body composed of a plurality of dielectric layers, 2 is a signal line conductor pattern, 3a is a first ground line conductor pattern, 3b is a second ground line conductor pattern, and 4 and 5 are signals. Side terminal electrodes 6 and 7 are ground side terminal electrodes.

Further, the noise filter 10 of the present invention has a signal side inductance component (hereinafter referred to as a signal side coil Cs) formed by connecting a plurality of signal line conductor patterns 2 ... A ground-side inductance component (hereinafter, referred to as a ground-side coil Cg ₁ ) formed by connecting a plurality of first ground line conductor patterns 3 a ..., A plurality of second ground line conductor patterns 3 b ... Has a ground-side inductance component (hereinafter, referred to as ground-side coil Cg ₂ ) configured as described above, and between the signal-side coil Cs and the first ground-side coil Cg ₁ the signal-side coil Cs and the second ground A predetermined capacitance is formed with the side coil Cg ₂ .

The laminated body 1 is made of, for example, a dielectric ceramic containing TiO ₂ as a main component, and has six dielectric layers 1a to 1a.
It consists of f. Here, the dielectric layer 1a is an upper margin layer, the dielectric layer 1f is a lower margin layer, and an interlayer between the dielectric layer 1a and the dielectric layer 1b and an interlayer between the dielectric layer 1c and the dielectric layer 1d. A linear or meandering signal line conductor pattern 2 is formed between the dielectric layers 1e and 1f (both are the first layers in the present invention).

Further, between the dielectric layer 1b and the dielectric layer 1c and between the dielectric layer 1d and the dielectric layer 1e (both are the second layers in the present invention), a straight line or a meandering line is formed. so,
First and second ground line conductor patterns 3 facing at least a part of the signal line conductor patterns 2 ...
a, 3b ... Are formed. The signal line conductor pattern 2 ..., the ground line conductor pattern 3a,
3b consists of a conductor which has Ag as a main component, for example.

Explaining the signal line conductor pattern 2 by using the signal line conductor pattern formed on the dielectric layer 1b as shown in FIG. 3, the shape of the signal line conductor pattern 2 is linear or meandering. .

The signal line conductor pattern 2 has a meandering shape including a plurality of straight line portions. That is, the first straight line portion 21, the second straight line portion 22, the third straight line portion 23, the fourth straight line portion 23, which are the input side extending portions of one end of the signal line conductor pattern 2 ...
Straight part 24, fifth straight part 25, sixth straight part 26,
The laminated body 1 (dielectric layer 1b) is composed of the seventh straight line portion 27 of the output side extending portion which is one end extending to the other end face in the longitudinal direction.

The first and second ground line conductor patterns 3a and 3b are arranged side by side between the same dielectric layers, and their shapes are linear or meandering. The ground line conductor patterns 3a and 3b are linear or meandering.

For example, referring to FIG. 4, for example, dielectric layers 1b and 1c.
The first and second ground line conductor patterns 3a and 3b between the layers (on the dielectric layer 1c) are shown.

The first ground line conductor pattern 3a comprises a first straight line portion 31a, a second straight line portion 32a, a third straight line portion 33a, and the above-mentioned ground side extending portion 34a.

The second ground line conductor pattern 3b comprises a first straight line portion 31b, a second straight line portion 32b, a third straight line portion 33b, and the above-mentioned ground side extending portion 34b.

The first and second ground line conductor patterns 3a and 3b each have a meandering shape including a plurality of straight line portions. The first ground line conductor pattern 3a is
The second ground line conductor is arranged so as to face a part of the signal line conductor pattern 2 ... Through a dielectric layer that separates the first layer from the second layer, for example, the dielectric layer 1b. The pattern 3b is arranged to face a part of the signal line conductor pattern 2, ... Through a dielectric layer that separates the first layer from the second layer, for example, the dielectric layer 1b.

The portion where the signal line conductor pattern 2 and the first ground line conductor pattern 3a are opposed to each other is the first straight line portion 21 of the signal line conductor pattern 2 and the first straight line of the first ground line conductor pattern 3a. The part 31a is
The second linear portion 22 and the second linear portion 32a face each other, and the third linear portion 23 and the third linear portion 33a face each other.

Further, the portion where the signal line conductor pattern 2 and the second ground line conductor pattern 3b face each other is
The seventh straight line portion 27 of the signal line conductor pattern 2 and the first straight line portion 31b of the second ground line conductor pattern 3b.
And the fifth straight line portion 25 and the third straight line portion 33b face each other.

The terminal electrodes 4, 5, 6, 7 are composed of a base conductor film containing Ag as a main component and a surface plating layer, and the signal side input / output terminal electrodes 4, 5 are end faces in the longitudinal direction of the laminate 1. Is formed in. Further, the ground side terminal electrodes 6 and 7 are formed on the end faces in the width direction of the laminated body 1.

The input terminal electrode 4 on the signal side is formed on the extended portion of the laminated body 1 at one end (the left end in FIG. 3) of the signal line conductor patterns 2 ... Arranged between the plurality of first layers. Directly connected. The output terminal electrode 5 on the signal side includes the signal line conductor patterns 2 ... Which are arranged between the plurality of first layers.
Is connected to the extended portion of the laminated body 1 at the other end (the right end in FIG. 3). That is, the signal side input / output terminal electrodes 4, 5
, The plurality of signal line conductor patterns 2 ... Are connected in parallel. The plurality of signal line conductor patterns 2 between the first layers are positively magnetically coupled to each other to form the signal side coil Cs.

The ground-side terminal electrode 6 has the first ground line conductor pattern 3a arranged between the plurality of second layers.
The ground-side extending portion 34a of ... Is formed in a portion extending to one end face (front side in FIG. 4) in the width direction of the multilayer body 1, and the ground-side terminal electrode 7 has a plurality of Second
The ground-side extending portion 34b of the second ground line conductor pattern 3b ... Arranged between the layers is formed in a portion extending to one end face in the width direction of the laminate 1 (the depth side in FIG. 4). Has been formed. That is, the ground-side terminal electrode 6 allows the plurality of first ground line conductor patterns 3a.
Are connected by-ground side extending portions 34a · ·, first constitutes a ground-side coil Cg _1, the ground-side terminal electrodes 7, a ground-side extension of the plurality of second ground line conductor patterns 3b · · The second ground side coil Cg ₂ is formed by being connected at the output portion 34b.

An equivalent circuit of the noise filter having the above structure is shown in FIG.

That is, an inductance component is generated in the signal side coil Cs composed of a plurality of line conductor patterns 2, and the magnetic path generated in the signal side coil Cs is the first and second ground side coils. Influencing Cg ₁ and Cg ₂ respectively, the ground line conductor pattern 3a,
Although a current is generated in 3b, this current flows down to the ground potential via the ground side terminal electrodes 6 and 7. Therefore, without forming a closed magnetic circuit around the signal line conductor pattern 2, ..., Good inductance components are derived from the respective signal side coils Cs and the first and second ground side coils Cg ₁ and Cg _2. can do. Further, since the signal line conductor pattern 2 and the first and second ground line conductor patterns 3a and 3b are opposed to each other, a capacitance component corresponding to the dielectric constants of the dielectric layers 1b to 1e, the facing distance, and the facing area is generated. Occurs and at the same time a mutual inductance component is obtained.

Since the inductance component and the capacitance component are of the distributed constant type as a whole, the noise filter can be excellent in noise removal with a simple structure.

In particular, structurally, between the second dielectric layers,
Since the ground line conductor patterns 3a and 3b are arranged separately and are directly connected to the ground side terminal electrode, the impedance can be reduced as compared with the case of a series of ground side coils. . As a result, the difference between the input / output impedance of the insertion circuit and the impedance of the noise filter can be immediately returned to the ground side terminal electrode 7 through the divided ground line conductor patterns 3a and 3b, so that stable characteristics, especially The attenuation characteristic in the high frequency region becomes excellent.

Further, the signal line conductor pattern 2 and the ground line conductor patterns 3a, 3b are made of linear or meandering conductors, and both ends or one ends thereof extend to the end face of the laminated body 1 and are formed at the extended portions. Signal line conductor patterns 2 arranged between different layers by the terminal electrodes 4 to 7,
Since it is connected to the ground line conductor patterns 3a and 3b, the reliability of the connection of the plurality of signal line conductor patterns 2 and the connection of the plurality of ground line conductor patterns 3a and the plurality of ground line conductor patterns 3b is dramatically improved. .

Further, the input / output end side of the signal line conductor pattern 2 is extended to face the end face in the longitudinal direction of the laminate 1 and is connected to the terminal electrodes 4 and 5, and one end of the ground line conductor pattern 3a is laminated. One end of the ground line conductor pattern 3b is led out to one end face in the width direction of the body 1, and one end of the ground line conductor pattern 3b is led out to the other end face in the width direction of the laminated body 1, and the terminal electrodes 6 and
Connected to 7. Therefore, since the terminal electrodes 4 to 7 are all arranged on the four end faces of the laminated body 1, when they are solder-bonded on the printed wiring board, they are laminated at predetermined positions on the printed wiring board due to the self-alignment effect of the solder. Body 1
Can be arranged.

Further, the ground line conductor pattern 3a,
Since the lead-out portion for connecting 3b to the terminal electrodes 6 and 7 extends from one end of each of the second layers near the approximate center of the plane portion, the ground line conductor pattern 3a,
The distance from 3b to the terminal electrodes 6 and 7 of the ground potential is very short, a highly efficient reflux effect can be obtained, and particularly, a wiring structure of a complicated conductor pattern is unnecessary, and the laminated body 1
Can be downsized.

Next, a method of manufacturing the noise filter of the above embodiment will be briefly described.

First, a dielectric ceramic such as BaTi is used.
A large green sheet containing O ₃ and TiO ₂ as main components is formed. The large green sheet is large enough to extract a plurality of noise filters.

Next, a conductor film which becomes a linear or meandering signal line conductor pattern 2 is provided in each region which becomes a noise filter of the large green sheet which becomes the dielectric layer 1b, the dielectric layer 1d and the dielectric layer 1f. Form. Both ends of the conductor film which becomes the signal line conductor pattern 2 are formed so as to extend to the boundary portion in the longitudinal direction of each element region.

Similarly, two conductor films, which are the linear or meandering ground line conductor patterns 3a and 3b, are formed in the respective regions which become the noise filters of the large green sheet which becomes the dielectric layer 1c and the dielectric layer 1e. To do. In addition, one end of the conductor film to be the ground line conductor patterns 3a and 3b is formed so as to extend to the boundary portion in the width direction of each element region.

Specifically, a simple substance of Ag or an Ag-based conductive paste such as an Ag alloy is screen-printed,
It is coated in a predetermined shape and dried.

Thereafter, the above-mentioned green sheets are sequentially laminated in accordance with the laminated structure together with the large-sized clean sheet to be the dielectric layer 1a, and they are laminated and integrated by thermocompression bonding.

Next, this laminated body is cut according to each element region.

Next, the individually cut laminated body is subjected to a peak temperature of, for example, 930 ° C. in an air atmosphere or an oxidizing atmosphere.
Bake at.

Next, the fired laminated body is barrel-polished, so that both ends of the signal line conductor pattern 2 and one ends (extending portions 34a, 34b) of the ground line conductor patterns 3a, 3b are completely formed on the end faces of the laminated body. To expose.

After that, a base conductor to be an input / output terminal electrode on the signal side and a terminal electrode on the ground side is provided on the treated surface.
It is formed by baking using an Ag-based conductive paste, and its surface is subjected to plating treatment such as Ni plating or solder plating.
As a result, the input / output terminal electrodes 4 and 5 and the ground potential terminal electrodes 6 and 7 are formed on the four end faces of the laminated body, respectively.

In the above noise filter, as shown in FIG. 6, for example, in the frequency band of 350 MHz or more, about 30
A stable attenuation amount of dB can be obtained, and a stable noise fill is obtained without particularly setting an upper limit of the frequency use range.

In the above-mentioned embodiment, the laminated body 1 is composed of 6 layers, but the dielectric layers 1a, 1f to be the margin layers are formed.
In the above, in order to increase the thickness, a plurality of dummy green sheets may be laminated. In addition, the number of stacked signal line conductor patterns 2 and ground line conductor patterns 3a and 3b is increased according to the inductance value and capacitance value of the signal side coil Cs and the ground side coils Cg ₁ and Cg _2.
Can be reduced. Even in this case, at least the signal line conductor pattern 2 and the ground line conductor patterns 3a and 3b face each other via the dielectric layer,
Allow the capacitive component to be generated.

Further, although only one noise filter element is formed in the laminated body, a plurality of noise filter elements may be arranged.

Further, the terminal electrodes 6 and 7 having the ground potential are formed on the end faces in the width direction of the laminate 1, respectively, but the terminal electrodes are formed only on one end face to form the first ground line conductor pattern. 3a and one end of the second ground line conductor pattern 3b may be connected at the same time.

[0053]

As described above, since the laminated body is made of a dielectric material and a sufficient capacitance component can be obtained between the signal side coil and the ground side coil, a plurality of signal line conductor patterns, Since the connection with the plurality of ground line conductor patterns is made through the directly connected terminal electrodes, the connection reliability is improved.

Moreover, since the ground line conductor pattern is divided and the impedance on the ground side can be lowered, the action of returning to the ground potential is increased, and the characteristics on the high frequency side can be improved.

[Brief description of drawings]

FIG. 1 is an external perspective view of a noise filter of the present invention.

FIG. 2 is an exploded perspective view of a laminated body portion of the noise filter of the present invention.

FIG. 3 is a plan view showing a signal line conductor pattern of the noise filter of the present invention.

FIG. 4 is a plan view showing a ground line conductor pattern of the noise filter of the present invention.

FIG. 5 is an equivalent circuit diagram of the noise filter of the present invention.

FIG. 6 is a characteristic diagram of the noise filter of the present invention.

[Explanation of symbols]

 1 --- Laminate body 2--Signal line conductor pattern 3a-First ground line conductor pattern 3b-Second ground line conductor pattern 4--Input side terminal electrode 5 .... Output side terminal electrodes 6, 7 .... Ground side terminal electrodes

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[Procedure amendment]

[Submission date] September 5, 1995

[Procedure amendment 1]

[Document name to be amended] Drawing

[Correction target item name] Fig. 6

[Correction method] Change

[Correction contents]

FIG. 6

Claims (1)

[Claims] 1. A laminated body formed by laminating a plurality of dielectric layers, and a linear shape disposed between the respective dielectric layers of the laminated body and having ends extending at both ends in the longitudinal direction of the laminated body. Alternatively, a plurality of meandering signal line conductor patterns and one of the signal line conductor patterns are arranged between the dielectric layers of the laminate, and one end portion extends to an end face in the width direction of the laminate. A plurality of first ground line conductor patterns facing each other, and one end portion of the signal line conductor pattern, which is arranged between the dielectric layers of the laminate and has one end extending to an end face in the width direction of the laminate. A plurality of second ground line conductor patterns facing a part thereof; signal-side terminal electrodes formed on both end faces of the laminate in the longitudinal direction and connected to both ends of the signal line conductor pattern; End face in the width direction Is formed, the first, second
And a ground side terminal electrode connected to one end of the ground line conductor pattern, the signal side coil is formed by connecting the plurality of signal line conductor patterns through the signal side terminal electrode, and a plurality of first side line electrodes are formed. A noise filter, wherein two ground side coils are formed by connecting the first and second ground line conductor patterns respectively via the ground side terminal electrodes.