JP2000196392A - Noise filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a compact noise filter in which filter characteristic can be easily controlled, manufacturing method can be simplified, and inductance component can be maximized. SOLUTION: For the noise filter, signal side terminal electrodes 6 and 7 and a ground side terminal electrode 8 are formed on the edge face of a laminated body 1 formed by alternately forming dielectric layers on which one side coil conductive patterns 2a, 2c, and 2e (3b and 3d) constituted of a capacity formation area 21 (31) and inductor parts 22 and 23 (32 and 33) extended to one edge side (the other edge side) of the capacity formation area 21 (31) and the other side coil connection patterns 5a, 5c, and 5e (4a and 4d) are formed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a noise filter, and more particularly to a distributed noise filter in which attenuation poles can be easily controlled.

[0002]

2. Description of the Related Art Conventionally, a noise filter is provided in a laminated body composed of a plurality of dielectric layers, a conductor pattern serving as a signal line conductor coil (hereinafter, simply referred to as a signal side coil) between the dielectric layers and a ground line conductor. A conductor pattern to be a coil (hereinafter simply referred to as a ground side coil) is formed, and a signal side coil and a ground side coil are formed in a laminated body, and a capacitance component is generated between both coils via a dielectric layer. I was letting it. In addition, connection between conductor patterns serving as different signal side coils has been performed by via hole conductors so as to penetrate the dielectric layer.

FIG. 5 is an exploded perspective view of a laminate showing a conductor pattern of a distributed constant type noise filter. It should be noted that the dielectric layer and the terminal electrode serving as the upper margin layer are omitted in the figure.

In the figure, an interlayer between a dielectric layer serving as an upper margin layer and a dielectric layer 51a, and dielectric layers 51d and 51e are shown.
, For example, on the dielectric layers 51a and 51e, the conductor patterns 52a and 52e serving as signal-side coils and via-hole conductors 55a and 55
5e is formed.

[0005] Also, between the dielectric layers 51a and 51b and between the dielectric layers 51e and 51f, for example, the dielectric layer 51
Conductor patterns 53b and 53f serving as ground-side coils and via-hole conductors 54b and 54f for forming signal-side coils are formed on b and 51f.

Further, between the dielectric layers 51b and 51c,
For example, on the dielectric layer 51c, a conductor pattern 52c serving as a signal side coil and a via hole conductor 55c for forming a ground side coil are formed.

Further, between the dielectric layers 51c and 51d,
For example, on the dielectric layer 51d, a conductor pattern 53d serving as a ground side coil and a via hole conductor 54d for forming a signal side coil are formed.

Each of the conductor patterns 52a, 53b, 52c,
53d, 52e, and 53f are formed in a substantially H shape.

For example, the conductor patterns 52a, 52c, 5
In 2e, the central rectangular pattern C is a capacitance forming region, and two conductor patterns extending from the capacitance forming region C to one end side (the right side of the dielectric layer 1a in the figure) constitute an inductor portion. I have.

The two conductor patterns extending from the capacitance forming region C to the other end (the left side of the dielectric layer 1a in the figure) are auxiliary capacitance forming portions.

Also, for example, the conductor patterns 53b, 53
In d and 53f, the central rectangular pattern C is a capacitance forming region, and two conductor patterns extending from the capacitance forming region C to the other end (the left side of the dielectric layer 1b in the figure) constitute an inductor portion. are doing. The two conductor patterns extending from the capacitance forming region C to one end (the right side of the dielectric layer 1b in the figure) are auxiliary capacitance forming portions.

In such a structure, the signal side coil is connected to the conductor pattern 52c from the tip of one inductor portion of the conductor pattern 52a via the via-hole conductor 54b.
Of the conductor pattern 5
The conductor pattern 52e is connected from the tip of one inductor portion to the tip of the other inductor portion of the conductor pattern 52e via the via-hole conductor 54d, and is connected to the via-hole conductor 54f from the tip of one inductor portion of the conductor pattern 52e. ing. This results in a coil of, for example, approximately three turns.

Similarly, the ground side coil is connected from the via-hole conductor 55a to one of the inductor portions of the conductor pattern 53b, and from one end of the other inductor portion of the conductor pattern 53b to one of the conductor patterns 53d via the via-hole conductor 55c. And the other end of the conductor pattern 53d is connected to the end of one inductor part of the conductor pattern 53f via the via-hole conductor 55e. Thereby, for example, a coil having approximately three turns is obtained.

The capacitance forming regions c of the conductor patterns 52a to 52e and 53b to 53f sandwich the dielectric layers 51b to 51e, and the auxiliary capacitance forming portion and a part of the inductor portion face each other. The components will be formed. As a result, the signal side coil and the ground side coil are coupled by the capacitance component.

Accordingly, the primary attenuation pole frequency of the distributed constant type noise filter is determined mainly by the self-inductance of the ground line side coil and the mutual inductance with the signal line side coil when the equivalent capacitance is unchanged. The secondary attenuation pole frequency is determined mainly by the self-inductance of the signal line side coil and the mutual inductance with the ground line side coil when the equivalent capacitance is invariable, and the filter characteristic can be arbitrarily controlled to the frequency characteristic. Is obtained.

The distributed constant noise filter described above is formed by substantially laminating four types of dielectric layers. These four types are shown in FIGS.

That is, the two inductor portions of the conductor patterns of the signal side coil and the ground side coil have different extending amounts, and the tip portions of both inductor portions are
Each dielectric layer was bent so as to extend to the center in the width (depth of the drawing) direction. This is because the conductor patterns 52b to 54f are used to form a series of signal side coils using the via hole conductors 54b to 54f, for example. The same applies to the ground coil side. And via-hole conductor 5
4b to 54f and 55a to 55e were formed at the center in the width direction of each dielectric layer.

[0018]

For this reason, via-hole conductors 54b to 54f, 55a to 55a to 54a to 54f are provided in each of the dielectric layers 1a to 1f.
A through hole serving as 55e is formed, a conductor is printed and filled in the through hole, and conductor patterns 52a to 52e, 53b to 53
In the case where f is formed by printing and the respective dielectric layers 1a to 1f are laminated, misalignment in processing of a through hole, misregistration of printing, lamination misalignment, etc. are inevitable. part width X ₂ of the inductor portion of the interval and the conductor pattern of the spacing X ₁ between the tip portion 100-2
It was necessary to set it to 00 μm or more.

For this reason, in the noise filters shown in FIGS. 5 and 6, there is a limit to downsizing, and extremely precise process control is required in the manufacturing process.

The present invention has been made in view of the above problems, and has as its object to individually control the primary attenuation pole and the secondary attenuation pole, and to maximize the inductor component. It is another object of the present invention to provide a noise filter that can be reduced in size and can be simplified in manufacturing process.

[0021]

According to the present invention, a signal side coil and a ground side coil are capacitively coupled to each other and connected to the signal side coil in a rectangular parallelepiped laminate in which a plurality of dielectric layers are laminated. A noise filter comprising two signal-side terminal electrodes and a ground-side terminal electrode connected to the ground-side coil, wherein the signal-side coil is formed between first dielectric layers of the laminate. A shape capacitor forming region, two inductor forming portions extending to one end side from the capacitor forming region, and a ground side connection pattern forming a ground side coil, between the second dielectric layer of the laminate, A substantially rectangular capacitance forming region forming the ground side coil, two inductor forming portions extending from the capacitance forming region to the other end, and a signal forming a signal side coil. Side connection pattern, the capacitance forming regions face each other via a dielectric layer, and one end of the ground-side connection pattern between the first dielectric layers is connected to the second dielectric layer. The noise filter is connected to one inductor forming portion, and one end of the signal side connection pattern between the second dielectric layers is connected to one inductor forming portion between the first dielectric layers.

[0022]

According to the noise filter of the present invention, since the conductor pattern serving as the signal side coil and the conductor pattern serving as the ground side coil can each be constituted by one type of pattern, the manufacturing process is greatly simplified.

The conductor pattern constituting each coil is composed of a substantially rectangular capacitor forming region and two inductor forming portions extending from the capacitor forming region to one end side. The lengths of the coils can be maximized because the lengths of the coils can be set to the same length, and the distal end portions are not displaced as shown in FIGS. Can be maximized. Further, the dead space around the conductor pattern on the dielectric layer can be reduced, and a compact laminate can be formed.

The primary attenuation pole frequency can be relatively easily controlled by the self-inductance of the ground line side coil and the mutual inductance with the signal line side coil. The secondary attenuation pole frequency can be relatively easily controlled by the mutual inductance with the coil.

That is, an arbitrary filter characteristic can be easily obtained.

[0026]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a noise filter according to the present invention will be described in detail with reference to the drawings. FIG. 1 is an external perspective view of a noise filter of the present invention, and FIG. 2 is an exploded perspective view of a laminate.

In FIG. 1, reference numeral 1 denotes a laminate,
Is a signal-side terminal electrode, 8 and 8 are ground-side terminal electrodes, and 9 is a mark indicating polarity.

The laminate 1 is made of alumina, BaTiO ₃ , T
iO ceramic material or a magnetic material such as ₂ (in the present invention is a ceramic material) and a plurality of dielectric layers 1x consisting crystallized glass material, 1 a to 1 e are formed by laminating.

Each of the laminates 1x, 1a to 1e has a conductor pattern made of, for example, a silver-based material or a copper-based material constituting a signal side coil and a ground side coil.

Specifically, between the dielectric layers 1x and 1a, between the layers 1b and 1c, between the layers 1d and 1e, for example, on the dielectric layers 1a, 1c and 1e, the signal side coil is provided. Are formed. In addition, ground-side connection patterns 5a, 5c, and 5e that simultaneously constitute a ground-side coil are formed between the layers.

Further, between the dielectric layers 1a and 1b, 1c
For example, the dielectric layers 1b, 1d
On d, a conductor pattern 3 constituting the ground side coil is provided.
b, 3d are formed. Further, between the layers, the signal side connection patterns 4d, 4d,
d is formed.

For example, the conductor pattern 2c constituting the signal side coil includes a substantially rectangular capacitor forming region 21 and two inductor forming portions 22 and 23 extending from the capacitor forming region 21 to one end side (right side in the figure). It is composed of
In addition, the other end side (left side in the figure) from the capacitance forming region 21
The two conductors 24 and 25 extending to the first portion are auxiliary portions of the capacitance forming region.

The conductor pattern 3b constituting the ground side coil includes a substantially rectangular capacitor forming region 31 and two inductor forming portions 32, 33 extending from the capacitor forming region 31 to the other end (left side in the figure). It is composed of The two conductors 34 and 35 extending from the capacitance forming region 21 to one end side (the right side in the drawing) are auxiliary portions of the capacitance forming region.

The two conductor patterns 3b and 2c are:
They face each other via the dielectric layer 1b. That is, the capacitance forming region 21 of the conductor pattern 2c and the capacitance forming region 31 of the conductor pattern 3b face each other. The inductors 22 and 23 of the conductor pattern 2c and the conductors 3 of the conductor pattern 3b
4, 35 are the inductor portions 32 of the conductor pattern 3b,
The conductor 33 and the conductors 24 and 25 of the conductor pattern 2c face each other.

Thus, a predetermined capacitance component is formed between the two conductor patterns 3b and 2c, and the two are capacitively coupled. The same applies to other conductor patterns formed between adjacent dielectric layers.

The ground-side connection patterns 5a, 5c
Are two inductor portions 3 of conductor patterns 3b and 3d to be ground side coils arranged between adjacent dielectric layers.
It is formed in a band shape so as to straddle the tip of 2, 33.
On one end of the strip-shaped ground-side connection patterns 5a, 5c, for example, via-hole conductors (indicated by dotted lines) penetrating the thickness of the lower dielectric layers 1a, 1c are formed, for example.
It is connected to the inductor portion 32 on one end side of the conductor patterns 3b and 3d serving as ground side coils. On the other end side of the strip-shaped ground-side connection patterns 5c and 5e, for example, via-hole conductors (indicated by dotted lines) penetrating through the thickness of the dielectric layers 1b and 1d located on the upper side are formed, and conductors serving as ground-side coils The other ends of the patterns 3b and 3d are connected to the inductor section 33. The other end of the connection pattern 5a and one end of the connection pattern 5e are connected to a ground-side end electrode formed on the outer surface of the multilayer body 1 via a conductor indicated by a dotted line.

The signal side connection patterns 4b and 4d are
Two inductor portions 2 of conductor patterns 2a, 2c, and 2e serving as signal-side coils disposed between adjacent dielectric layers
It is formed in a band shape so as to straddle the tip of 2, 23.
On one end of each of the strip-shaped ground-side connection patterns 4b and 4d, for example, a via-hole conductor (indicated by a dotted line) penetrating the thickness of the dielectric layers 1a and 1c located on the upper side is formed.
It is connected to the inductor portion 22 on one end side of the conductor patterns 2a and 2c to be signal side coils. Further, on the other end side of the strip-shaped ground-side connection patterns 4b, 4d, for example, via-hole conductors (indicated by dotted lines) penetrating the thickness of the dielectric layers 1b, 1d located on the lower side are formed, and serve as signal-side coils. It is connected to the inductor part 23 on the other end side of the conductor patterns 2c and 2e. The other inductor portion 23 of the conductor pattern 2a is formed on the outer surface of the multilayer body 1 and is connected to the signal-side terminal electrode 6 as shown by a dotted line, and one inductor portion 22 of the conductor pattern 2a is As shown by, it is formed on the outer surface of the multilayer body 1 and is connected to the signal-side terminal electrode 7.

That is, according to the above-described structure, the distance from the signal side terminal electrode 6 (the tip of the other inductor portion 23 of the conductor pattern 2a) to the signal side terminal electrode 7 (the tip of the one inductor portion 23 of the conductor pattern 2e). And conductor pattern 2
a conductor pattern 2a at the tip of the other inductor section 23
(Actually, the other inductor portion 23 and the capacitance forming region 2
1, a pattern with one inductor section 22 as a path),
A signal side coil composed of the via hole conductor, the signal side connection pattern 4b, the via hole conductor, the conductor pattern 2c, the via hole conductor, the signal side connection pattern 4d, the via hole conductor, and the conductor pattern 2e is configured.

The ground-side terminal pattern 8 (one end of the ground-side connection pattern 5a or the other end of the ground-side connection pattern 5e) is also connected to the ground-side connection pattern 5a.
Via-hole conductor, conductor pattern 3b, via-hole conductor,
A ground side coil composed of the conductor pattern 3d is formed.

In the figure, the signal side coil has approximately three turns, and the ground side coil has approximately two turns, and the number of turns (self-inductance) differs greatly. This may be made different in order to control the attenuation station frequency. In order to make the inductance components of the two substantially the same, the capacitance shaping regions 21 and 31 are formed closer to one side (the right side in the figure) in each of the dielectric layers 1a to 1e as shown in FIG. By compensating for the difference in the numbers, the conductor length of the signal side coil and the conductor length of the ground side coil can be made the same.

In this way, the primary attenuation pole frequency of the noise filter is determined mainly by the self inductance of the ground line side coil and the mutual inductance with the signal line side coil when the equivalent capacitance is unchanged. The secondary attenuation pole frequency is determined mainly by the self-inductance of the signal line side coil and the mutual inductance with the ground line side coil when the equivalent capacitance is invariable, and the filter characteristic can be arbitrarily controlled to the frequency characteristic. Is obtained.

Each of the conductor patterns 2a to 2e, 3b,
If the length of the 3d conductors 24, 25, 34, 35 is controlled, the capacitance component between them is changed, thereby obtaining a filter characteristic that can be arbitrarily controlled to a frequency characteristic.

The signal-side terminal electrodes 6 and 7 and the ground-side terminal electrode 8 formed on a pair of opposed ends of the multilayer body 1 are plated with a surface of a baked conductor film of silver or the like. . The marker 9 indicating the polarity direction has a characteristic shape, and is formed by plating the surface of a baked conductive film of silver or the like, or is formed by baking glass containing a dye.

The feature of the present invention is that the inductor portion 2 formed on each of the conductor patterns 2a to 2e, 3b, 3d
2, 23, 32, 33 extend to their respective end sides. Alternatively, they extend by the same extension amount and bend toward the center side. That is, the conductor portion (spiral shape) forming each coil has a substantially rectangular shape when viewed from a plane. That is, as shown in FIGS. 5 and 6 of the related art, the tip of the inductor portion is not displaced in the end direction.

As a result, the planar shapes of the signal side coil and the ground side coil can be substantially approximated to the planar shape of the dielectric layer, and the conductor patterns 2 of the dielectric layers 1a to 1e can be approximated.
a to 2e, 3b, 3d and connection patterns 4b, 4d, 5a
5e can be increased, and the dead space around the coil can be minimized. Further, there is no any way to consider the distance X ₁ of the front end portion of the tip and the other the inductor of the conventional as one inductor unit.

As a result, the inductance component of the coil can be maximized, and the shape of the dielectric layers 1a to 1e can be reduced, whereby a small-sized laminate 1 can be achieved.

In forming the signal-side coil and the ground-side coil, the conductor patterns 2a to 2e, 3b, and 3d and the connection patterns 4b, 4d, and 5a to 5e are two types, although the formation positions of the via hole conductors are different. It can be constituted by a pattern, and the manufacturing method can be simplified.

Next, the laminate 1 having the above structure is manufactured by the following manufacturing method.

First, the dielectric layers 1x, 1a-1
e is a dielectric sheet made of a dielectric material BaTiO.
₃ , a ceramic powder containing at least TiO ₃ and an organic vehicle are homogeneously kneaded to a predetermined thickness (20 μm to 100 μm).
μm), and cut into a predetermined size.

Next, a through hole (a hole diameter of 50 μm) serving as a via hole conductor is formed at a predetermined position (a position at any one of the connection patterns 4b, 4d, 5a to 5e) of the dielectric sheet.
To 200 μm) by punching or the like.

Next, a metal powder of an Ag-based material (Ag alone, an Ag alloy such as Ag-Pd), a Cu-based material, and if necessary, a low melting glass frit and an organic vehicle are homogeneously filled in the above-mentioned through-hole. The conductive paste obtained by mixing is filled to form a conductor serving as a via-hole conductor, and a conductor pattern 2 serving as a signal-side coil is formed on the surface of the sheet.
a, 2c and 2e, conductive films to be ground line conductive patterns 3b and 3d, connection patterns 5a and 5d
The conductor films to be c, 5e, 4b, and 4d have a thickness of 1 μm to 20 μm by screen printing of the conductive paste described above.
Formed.

Next, the respective sheets are selectively laminated in consideration of the lamination order shown in FIG. 2 and integrated by thermocompression bonding. Thereafter, if necessary, the sheet is cut to a final dimension in consideration of sintering shrinkage, or a division groove for division in the final step is formed.

Next, the laminate composed of the dielectric sheets is fired in a predetermined atmosphere and a predetermined peak temperature. When an Ag-based conductive paste is used as the above-mentioned conductive paste, the treatment is performed in an oxidizing atmosphere or a neutral atmosphere, and when a Cu-based conductive paste is used, the treatment is performed in a reducing atmosphere or a neutral atmosphere. Also,
The peak temperature is processed at a temperature necessary for the dielectric sheet to undergo a sintering reaction, and the metal component of the conductive paste is adjusted to withstand this temperature. For example, when Ag or Cu is used as the conductive paste, the peak temperature is 1050 ° C. or lower, and when firing at a temperature higher than that, an alloy such as Pd is used.

At about 500 ° C. until the temperature rises to about 1000 ° C., the dielectric vehicle, the conductive film, and the organic vehicle components contained in the conductor are burned off.

The laminate 1 fired as described above
Then, via-hole conductors exposed on the outer surface of the laminate 1 and conductor films to be the terminal electrodes 6, 7, and 8 on exposed portions of the conductors, respectively,
The conductive film is formed by baking, and then the surface of the conductive film is plated.

FIGS. 3A and 3B are plan views of two types of dielectric layers 1y and 1z used in another noise filter of the present invention. On the dielectric layer 1y, a conductor pattern 2y constituting a signal side coil and a connection pattern 5y constituting a ground side coil are formed. On the dielectric layer 1z, a conductor pattern 3z forming a ground side coil and a connection pattern 4z forming a ground side coil are formed. FIG. 3 does not show the conductors 24, 25, 34, and 35 that are the auxiliary capacitance forming regions of the conductor pattern shown in FIG. That is, while the conductor pattern is substantially H-shaped in FIG. 2, it is substantially C-shaped in FIG. Such a structure is used when a capacitance component formed between both coils is unnecessary.

The inventor of the present invention has found that the outermost shape of the coil (shape when it is rectangular) is formed by using dielectric layers of the same dimensions in the pattern of the structure shown in FIG. 2 and the pattern shown in FIG.
Formed the same noise filter and measured its characteristics.

In FIG. 4, (a) shows the characteristics of the noise filter of the present invention, and (b) shows the characteristics of the conventional noise filter. From the figure, the characteristic of the product of the present invention is that the attenuation pole is formed steeply, and a sufficient amount of attenuation can be obtained in a wide frequency band. This indicates that the product of the present invention is a noise filter having a high degree of freedom in which filter characteristics can be arbitrarily set by setting the inductance component of each coil or setting the capacitance component.

As a method of manufacturing a laminate having the structure of the above-described embodiment, in addition to a multi-layer method of forming green sheets on which dielectric layers 1x to 1e are formed and via-hole conductors and printed conductor patterns are formed, It may be formed by printing multiple layers by repeating selective printing of a dielectric paste to be a body layer and selective printing of a conductive paste.

The shape of the inner area of the above-described coil is substantially square according to the shape of the dielectric layer, and a notch may be formed at the corner to form an N-square. The corners may be arc-shaped.

[0061]

As described above, the filter characteristics can be easily controlled, the inductor component can be maximized, and the dead space around the signal side coil and the ground side coil arranged on the dielectric layer can be reduced. It becomes a noise filter.

[Brief description of the drawings]

FIG. 1 is a perspective view of a noise filter according to the present invention.

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

FIG. 3A is a schematic plan view of a dielectric layer on which a conductor pattern serving as a signal side coil and a connection pattern of a ground side coil are formed, and FIG. 3B is a diagram illustrating a conductor pattern serving as a ground side coil and a signal side coil; FIG. 5 is a schematic plan view of a dielectric layer on which the connection pattern of FIG.

FIG. 4 is a characteristic diagram for comparing characteristics of the noise filter of the present invention and a conventional noise filter.

FIG. 5 is an exploded perspective view of a laminated body part constituting a conventional noise filter.

FIGS. 6A to 6D are schematic plan views of a dielectric layer on which a conductor pattern of a conventional noise filter is formed.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... laminated body 1x, 1a-1e ... dielectric layer 2a, 2c, 2e ... conductor pattern of signal side coil 21 ... capacity formation area 22, 23 ... inductor part 3b, 3d ··· conductor pattern of signal side coil 31 ··· capacity formation area 32, 33 ··· inductor part 6, 7 ··· signal side terminal electrode electrode 8 ··· ground side terminal electrode

Claims (1)

[Claims] 1. A signal-side coil and a ground-side coil are arranged in a rectangular parallelepiped laminate in which a plurality of dielectric layers are laminated, and two signals connected to the signal-side coil are arranged. In a noise filter formed by forming a side terminal electrode and a ground side terminal electrode connected to the ground side coil, a substantially rectangular capacitance forming region forming the signal side coil between first dielectric layers of the laminated body And two inductor forming portions extending to one end side from the capacitance forming region, and a ground side connection pattern forming a ground side coil, wherein the ground side coil is provided between a second dielectric layer of the laminate. A substantially rectangular capacitor forming region, and two inductor forming portions extending from the capacitor forming region to the other end side;
A signal-side connection pattern forming a signal-side coil; the capacitance-forming regions oppose each other via a dielectric layer; and one end of a ground-side connection pattern between the first dielectric layers is The second dielectric layer is connected to one inductor forming portion, and one end of the signal side connection pattern between the second dielectric layers is connected to one inductor forming portion between the first dielectric layers. Noise filter.