JP2000151324A - Laminated type noise filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the laminated type noise filter which has superior high-frequency characteristics and can obtain large inductance and electrostatic capacity. SOLUTION: This laminated type noise filter 1 is equipped with a laminate constituted by laminating a rectangular insulating sheet 2 which has coil conductors 4a and 4b, forming a coil 8, and coil conductors 5a and 5b for forming a coil 9, on the respective surfaces and an insulating sheet 3 which has capacitor conductors 7a and 7b constituting a capacitor 10 on the respective surfaces. The coils 8 and 9 have the coil conductors 4a and 4b, and 5a and 5b connected electrically and have axes parallel to the laminating direction of the laminate body and the mounting surface of the laminate body. The noise filter 1 satisfies the condition W>L, where L is the length of the laminate in the laminating direction, and W is the width perpendicular to the laminating direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a multilayer noise filter, and more particularly to a multilayer noise filter used as a power line noise filter or the like.

[0002]

2. Description of the Related Art As this kind of laminated noise filter,
For example, the one shown in FIG. 9 has been proposed. This laminated noise filter 81 is a capacitor formed by laminating a coil portion 82 formed by laminating insulating sheets 102 provided with coil conductors 85a to 85c and insulating sheets 102 provided by capacitor conductors 94 and 95, respectively. Part 84,
The coil unit 83 includes an insulating sheet 102 provided with coil conductors 86a to 86c. The coil conductors 85 a to 85 c are electrically connected in series via via holes 96 b and 96 c provided in the insulating sheet 102, respectively, to form a coil 91. Coil conductor 86
a to 86 c are electrically connected in series via via holes 96 g and 96 h provided in the insulating sheet 102 to form a coil 92.

[0005] Capacitor conductors 94 and 95 are opposed to each other with an insulating sheet 102 interposed therebetween to form a feedthrough capacitor 93. The capacitor conductor 95 is electrically connected to one end of the coil 92 via the via hole 96f, and is also electrically connected to one end of the coil 91 via the via holes 96e and 96d. Capacitor conductor 94
Is formed with a space 94a, and a gap of a predetermined size is secured between the space 94a and the via hole 96d.

After the respective insulating sheets 102 are stacked, they are integrally fired to form a rectangular parallelepiped laminate 110 as shown in FIG. FIG. 10 shows coils 91 and 92.
And the capacitor 93 are schematically shown in the laminated body 110. An input external electrode 105 and an output external electrode 106 are provided at the left and right ends of the laminate 110, respectively.
Ground external electrodes 10 are provided on the front and rear side surfaces of
7a and 107b are provided. Input external electrode 105
Is a drawing via hole 9 provided in the insulating sheet 102.
It is electrically connected to one end of the coil 91 via the via hole 7a and the via hole 96a. Output external electrode 106
Is a drawing via hole 9 provided in the insulating sheet 102.
7b, it is electrically connected to one end of the coil 92. The ground external electrodes 107a and 107b are electrically connected to ends of the capacitor conductor 96.

The lower surface 110a of the laminate 110 is used as a mounting surface when the noise filter 81 is soldered to a printed circuit board or the like. With respect to the mounting surface 110a, the sheet 1
The stacking direction of 02 and the axial directions of the coils 91 and 92 are parallel. The axial directions of the coils 91 and 92 and the stacking direction of the multilayer body 110 are determined by the input / output external electrodes 10.
Perpendicular to 5,106. By adopting such a structure, the stray capacitance generated between the input / output external electrodes 105 and 106 and the coils 91 and 92 is reduced, and the noise filter 81 having excellent insertion loss characteristics in a high frequency region.
Can be obtained. FIG. 11 is a schematic horizontal cross-sectional view of the noise filter 81.

[0006]

However, in the conventional laminated noise filter 81, the dimension of the stacked body 110 in the stacking direction is defined as the length L, and the dimension in the direction perpendicular to the stacking direction is defined as the width W. L> W. For this reason, the size of the insulating sheet 102 is small,
Coil conductors 85a-85 formed on insulating sheet 102
85c, 86a to 86c and the capacitor conductors 94, 95 could not be increased. Therefore, the coils 91,
Since 92 has a small diameter and the capacitor conductors 94 and 95 have a small facing area, it is not possible to obtain a large inductance or capacitance required for a power line noise filter or the like.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a multilayer noise filter which is excellent in high-frequency characteristics and can obtain large inductance and capacitance.

[0008]

In order to achieve the above objects, a laminated noise filter according to the present invention is provided by electrically connecting coil conductors to each other, and in a direction in which the laminated bodies are stacked and mounting of the laminated bodies. A coil having an axis parallel to the surface is formed, and a capacitor is formed by the capacitor conductor. A dimension of the stacked body in the stacking direction is defined as a length dimension L, and a dimension in a direction perpendicular to the stacking direction. Is a width dimension W, the condition W> L is satisfied.

With the above configuration, the size of the insulating sheet is increased, and the coil conductor and the capacitor conductor can be formed large on the insulating sheet.

In the laminated noise filter according to the present invention, two coil units and two capacitor units are alternately stacked, and the coil of the coil unit is used as a serial element.
A ladder-type circuit comprising a capacitor of the capacitor unit as a parallel element, wherein the permeability of one of the two coil units is made higher than the permeability of the other coil unit, and the two capacitors are formed. The dielectric constant of one of the capacitors is higher than the dielectric constant of the other capacitor.

With the above arrangement, the coils and capacitors of the coil portion and the capacitor portion having a high magnetic permeability and a high permittivity have a large noise removing ability in a relatively low frequency region, and the coil portion and the capacitor portion having a low magnetic permeability and a low permittivity are provided. The coil and the capacitor have a large noise removing capability in a relatively high frequency range.

Further, when the capacitor is a feedthrough capacitor, the residual inductance (equivalent series inductance) of the capacitor is reduced, and noise can be removed up to a high frequency region.

[0013]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showing a laminated noise filter according to an embodiment of the present invention.

[First Embodiment, FIGS. 1 to 4] As shown in FIG. 1, a multilayer noise filter 1 includes coil portions 12, 1
3 and a capacitor part 14, and the coil conductors 4a,
4b and a coil-shaped conductor 5a, 5b on the surface, respectively, a rectangular insulating sheet 2 and capacitor conductors 7a, 7b
Are provided on an insulating sheet 3 and the like provided on the respective surfaces.

In order to obtain a large current capacity, a plurality of (two in the first embodiment) coil conductors 4a are electrically connected in parallel via via holes 6a and 6b provided in the insulating sheet 2. I have. And a plurality of coil conductors 4b
They are electrically connected in parallel via the via holes 6d and 6e. Furthermore, the coil conductors 4a and 4b
c to form a double spiral coil 8 which is electrically connected in series and has an axis parallel to the direction in which the insulating sheets 2 are stacked.

Similarly, a plurality of coil conductors 5a are electrically connected in parallel via via holes 6j and 6k provided in insulating sheet 2, and a plurality of coil conductors 5b are
m and 6n, and are electrically connected in parallel. The coil conductors 5a and 5b are electrically connected in series via the via holes 6l to form a double spiral coil 9 having an axis parallel to the direction in which the insulating sheets 2 are stacked. Coil 8
And the winding direction of the coil 9 are the same.

The capacitor conductors 7a and 7b are opposed to each other with the insulating sheet 3 interposed therebetween, and constitute a feedthrough capacitor 10. The capacitor conductor 7b functions as the center conductor of the feedthrough capacitor 10 together with the via holes 6g to 6i formed in the insulating sheet 3. One end of this center conductor (via hole 6g) is connected to one end of coil 8 (coil conductor 4b) via via hole 6f formed in insulating sheet 2.
The other end of the center conductor (via hole 6i) is electrically connected to one end of the coil 9 (coil conductor 5a). A space 18 for securing a predetermined gap around the via holes 6g and 6i is formed in the center of the capacitor conductor 7a. The feedthrough capacitor 10 has a small residual inductance (equivalent series inductance) and can remove noise up to a high frequency range.

The insulating sheets 2 and 3 are formed by forming a slurry material prepared by kneading a magnetic material (for example, ferrite) or a dielectric material with a binder. Desirably, a material having high magnetic permeability is used for the insulating sheet 2 forming the coil portions 12 and 13. In the first embodiment, a magnetic material having a magnetic permeability of about 300 to 800 is used, and the coils 8 and 9 are not magnetically saturated even when a small amount of current flows. On the other hand, a material having a large dielectric constant is used for the insulating sheet 3 constituting the capacitor portion 14. The coil conductors 4a, 4b, 5a, 5b and the capacitor conductors 7a, 7b are made of Ag, Pd, Cu, Au, Ag-P
d, etc., and is formed by a method such as printing.

After the sheets 2 and 3 are stacked and pressed, they are integrally fired to form a rectangular parallelepiped laminate 20 as shown in FIG. The sheets 2 are stacked to form the coil units 12 and 13, and the sheets 3 are stacked to form the capacitor unit 14. An input external electrode 22 and an output external electrode 23 are provided on left and right side surfaces of the laminated body 20 in which the coil parts 12 and 13 are laminated with the capacitor part 14 interposed therebetween, and are provided at the front and rear ends of the laminated body 20. Are provided with ground external electrodes 24a and 24b. The input external electrode 22 is electrically connected to one end (coil conductor 4a) of the coil 8 via a via hole 6p provided in the insulating sheet 2. The output external electrode 23 is connected to the via hole 6o.
And is electrically connected to one end (coil conductor 5b) of the coil 9 through the. Ground external electrodes 24a, 24b
Are electrically connected to both ends of the capacitor conductor 7a.

The lower surface 20a of the laminate 20 is used as a mounting surface when the noise filter 1 is soldered to a printed board or the like. The stacking direction of the sheets 2 and 3 and the axial direction of the coils 8 and 9 are parallel to the mounting surface 20a.
The axial directions of the coils 8 and 9 and the stacking direction of the laminate 20 are perpendicular to the input / output external electrodes 22 and 23. By adopting such a structure, the stray capacitance generated between the input / output external electrodes 22, 23 and the coils 8, 9 is reduced, and the noise filter 1 having excellent insertion loss characteristics in a high frequency region is obtained. Can be. Furthermore, when the dimension of the stacked body 20 in the stacking direction is a length dimension L and the dimension in a direction perpendicular to the stacking direction is a width dimension W, the noise filter 1 satisfies the condition of W> L. .
FIG. 3 is a schematic cross-sectional view of the noise filter 1 and FIG.
2 is an electrical equivalent circuit diagram of the noise filter 1. FIG. The coils 8, 9 and the capacitor 10 constitute a T-type LC circuit.

In the laminated noise filter 1 having the above configuration, since the length L and the width W of the laminated body 20 are set so that W> L, the size of the insulating sheets 2 and 3 is reduced. Of the coil conductors 4a, 4b, 5a, 5b and the capacitor conductors 7 on the insulating sheets 2, 3.
a and 7b can be formed large. As a result, the diameters of the coils 8 and 9 and the opposing areas of the capacitor conductors 7a and 7b can be increased, the inductance of the coils 8 and 9 can be increased, and the capacitance of the capacitor 10 can be increased.

[Second embodiment, FIGS. 5 to 8] As shown in FIG.
Insulating sheet 32 provided on each surface with a to 36c
An insulating sheet 33 provided on the surface with capacitor conductors 38a and 38b, an insulating sheet 34 provided on the surface with coil conductors 37a to 37c, and an insulating sheet provided on the surface with capacitor conductors 39a and 39b, respectively. 35 and the like.

The coil conductors 36a to 36c are electrically connected in series via via holes 41a and 41b provided in the insulating sheet 32, and have a spiral coil having an axis parallel to the direction in which the insulating sheets 32 are stacked. 51 is set.
The coil conductors 37a to 37c are electrically connected in series via via holes 41g and 41h provided in the insulating sheet 34, and form a spiral coil 52 having an axis parallel to the direction in which the insulating sheets 34 are stacked. You. The winding direction of the coil 51 and the winding direction of the coil 52 are the same.

The capacitor conductors 38a and 38b are opposed to each other with the insulating sheet 33 interposed therebetween, and constitute a feedthrough capacitor 53. The capacitor conductor 38b functions as a center conductor of the feedthrough capacitor 53 together with the via holes 41d to 41f formed in the insulating sheet 33. One end (via hole 41d) of this center conductor is electrically connected to one end (coil conductor 36c) of the coil 51 via a via hole 41c formed in the insulating sheet 32, and the other end of the center conductor. (Via hole 41f) is electrically connected to one end (coil conductor 37a) of the coil 52. A via hole 4 is provided at the center of the capacitor conductor 38a.
A space 43 for securing a predetermined gap is formed between 1d and 41f.

Similarly, capacitor conductors 39a and 39b
Are opposed to each other with the insulating sheet 35 interposed therebetween, and constitute a feedthrough capacitor 54. The capacitor conductor 39b functions as the center conductor of the feedthrough capacitor 54 together with the via holes 41j to 41l formed in the insulating sheet 35. One end (via hole 41j) of the center conductor is connected to the coil 5 via a via hole 41i formed in the insulating sheet 34.
2 is electrically connected to one end (coil conductor 37c). At the center of the capacitor conductor 39a, a space 43 for securing a predetermined gap between the via hole 41j and 41l is formed.

Here, the magnetic permeability of the insulating sheet 32 is set higher than the magnetic permeability of the insulating sheet 34, and the dielectric constant of the insulating sheet 33 is set higher than the dielectric constant of the insulating sheet 35. In the second embodiment, a magnetic material having a magnetic permeability of 300 to 800 is used as the material of the insulating sheet 32 to increase the inductance of the coil 51, thereby improving the noise removing effect in a relatively low frequency region. . As a material of the insulating sheet 33, a dielectric material having a dielectric constant of 1000 or more is used to increase the capacitance of the capacitor 53, thereby improving a relatively low frequency noise removing effect. The material of the insulating sheet 34 has a magnetic permeability of 5-1.
In the high frequency region, the coil 52 is
Is increased, and the noise removal effect in a relatively high frequency region (several hundred MHz to GHz band) is improved. As a material of the insulating sheet 35, a dielectric material having a dielectric constant of about 10 or a material having a low dielectric constant (about 10 to 20) is used as a material of the insulating sheet 34. By using a similar magnetic material or the like, the capacitance of the capacitor 54 is reduced, and the relatively high frequency noise removal effect is improved.

After the sheets 32 to 35 are stacked and pressed, they are integrally fired to form a rectangular parallelepiped laminate 60 as shown in FIG. The sheets 32 and 34 are stacked to form coil portions 55 and 56, respectively, and the sheets 33 and 35 are stacked to form capacitor portions 57 and 5 respectively.
8. Coil units 55 and 56 and capacitor unit 5
The input external electrode 62 and the output external electrode 63 are provided on the left and right side surfaces of the stacked body 60 in which 7, 58 are alternately stacked.
Are provided, and ground external electrodes 64 a and 64 b are provided at the front and rear ends of the stacked body 60. The input external electrode 62 is connected to one end (the coil conductor 3) of the coil 51 via a via hole 41m provided in the insulating sheet 32.
6a). The output external electrode 63 is
It is electrically connected to the capacitor conductor 39b of the capacitor 54 via the via hole 41l. The ground external electrodes 64a and 64b are electrically connected to both ends of the capacitor conductors 38a and 39a, respectively.

The lower surface 60a of the laminate 60 is used as a mounting surface when the noise filter 31 is soldered to a printed circuit board or the like. For the mounting surface 60a, the sheets 32 to 3
The stacking direction of 5 and the axial directions of the coils 51 and 52 are parallel. The axial directions of the coils 51 and 52 and the stacking direction of the stacked body 60 correspond to the input / output external electrodes 62 and 63.
Perpendicular to Further, when the dimension of the stacked body 60 in the stacking direction is a length dimension L and the dimension in a direction perpendicular to the stacking direction is a width dimension W, the noise filter 31 satisfies the condition of W> L. .

FIG. 7 is a schematic cross-sectional view of the noise filter 31, and FIG. 8 is an electric equivalent circuit diagram of the noise filter 31. The noise filter 31 has a ladder-type circuit between the input external electrode 62 and the output external electrode 63, using the coils 51 and 52 as serial elements and the capacitors 53 and 54 as parallel elements.

In the laminated noise filter 31 having the above-described structure, the length L and the width W of the laminated body 60 are set so that W> L.
Of the insulating sheet 32 to
The coil conductors 36a to 36c, 37a to 37c and the capacitor conductors 38a, 38b, 39a, 39b can be formed on the 35 larger. As a result, the coils 51, 52
Of the capacitors 53 and 5
4 can be increased in capacitance.

The coil 51 and the capacitor 53 on the input external electrode 62 side have a large noise removing ability in a relatively low frequency region, and the coil 52 and the capacitor 54 on the output external electrode 63 side have a large noise removing ability in a relatively high frequency region. large. Therefore, the noise filter 31 can remove noise in a wide band from a low frequency to a high frequency.

[Other Embodiments] The multilayer noise filter according to the present invention is not limited to the above-described embodiment, but can be variously modified within the scope of the gist.

The combination circuit of the coil and the capacitor is
The shape is not limited to the T shape or the ladder shape, and may be, for example, an L shape or the like in which the coil portion 13 is omitted in the first embodiment. Further, the capacitor is not limited to a feed-through capacitor, but may be an ordinary two-terminal capacitor or a three-terminal capacitor. Further, the electrical connection between the input / output electrodes and the internal conductors such as the coil conductor and the capacitor conductor is not limited to the one using the via hole. A lead electrode extending from the end of the internal conductor to the edge of the insulating sheet may be provided on the insulating sheet, and the input / output electrode and the internal conductor may be electrically connected via the lead electrode.

Further, in the case of manufacturing a laminated noise filter, the method is not necessarily limited to a method in which insulating sheets provided with coil conductors and capacitor conductors on their surfaces are stacked and then integrally fired. As the insulating sheet, a pre-fired one may be used. Further, a laminated noise filter may be manufactured by a method described below. That is, after forming an insulating layer with a paste-like insulating material by a method such as printing, a paste-like conductive material is applied to the surface of the insulating layer to form a coil conductor or a capacitor conductor. Next, a paste-like insulating material is applied from above the coil conductor or the like to form an insulating layer in which the coil conductor or the like is embedded. Similarly, a noise filter having a layered structure can be obtained by sequentially applying layers.

[0035]

As apparent from the above description, according to the present invention, the dimension of the laminate in the stacking direction is defined as the length dimension L, and the dimension in the direction perpendicular to the stacking direction is defined as the width dimension W. Then, by satisfying the condition of W> L,
The size of the insulating sheet is increased, and the coil conductor and the capacitor conductor can be formed large on the insulating sheet. As a result, the insertion loss characteristics in the high frequency region are excellent,
In addition, a multilayer noise filter having a large inductance and a large capacitance can be obtained.

Further, the magnetic permeability of one of the two coil portions is made higher than the magnetic permeability of the other coil portion, and the dielectric constant of one of the two capacitor portions is changed to the other capacitor. By increasing the dielectric constant of the coil and capacitor of the coil and capacitor with high magnetic permeability and dielectric constant, the coil and capacitor of the coil and capacitor with low magnetic permeability and dielectric constant have relatively large noise removal ability in a relatively low frequency region. The coil and capacitor of the section have a large noise removal capability in a relatively high frequency region. Therefore, noise can be removed in a wide band from low frequency to high frequency.

Further, when the capacitor is a feedthrough capacitor, the residual inductance (equivalent series inductance) of the capacitor is reduced, and noise can be removed up to a high frequency region.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view showing the configuration of a first embodiment of a multilayer noise filter according to the present invention.

FIG. 2 is an external perspective view of the multilayer noise filter shown in FIG.

FIG. 3 is a schematic cross-sectional view of the stacked noise filter shown in FIG. 2;

FIG. 4 is an electrical equivalent circuit diagram of the multilayer noise filter shown in FIG.

FIG. 5 is an exploded perspective view showing the configuration of a second embodiment of the multilayer noise filter according to the present invention.

6 is an external perspective view of the multilayer noise filter shown in FIG.

FIG. 7 is a schematic horizontal sectional view of the multilayer noise filter shown in FIG. 6;

8 is an electrical equivalent circuit diagram of the multilayer noise filter shown in FIG.

FIG. 9 is an exploded perspective view showing a configuration of a conventional laminated noise filter.

10 is an external perspective view of the multilayer noise filter shown in FIG.

11 is a schematic horizontal cross-sectional view of the multilayer noise filter shown in FIG.

[Explanation of symbols]

1, 31: laminated noise filter 2, 3, 32-35: insulating sheet 4a, 4b, 5a, 5b, 36a-36c, 37a-3
7c: Coil conductors 6a to 6p, 41a to 41m: Via holes 7a, 7b, 38a, 38b, 39a, 39b: Capacitor conductors 8, 9, 51, 52: Coils 10, 53, 54: Through capacitors 12, 13, 55, 56 ... Coil part 14, 57, 58 ... Capacitor part 20, 60 ... Laminated body L ... Length dimension W ... Width dimension

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[Procedure amendment]

[Submission date] February 14, 2000 (2000.2.1
4)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claims

[Correction method] Change

[Correction contents]

[Claims]

 ──────────────────────────────────────────────────続 き Continued on the front page F-term (reference)

Claims (3)

[Claims] 1. A laminate comprising: a coil portion formed by stacking a plurality of insulating layers and a plurality of coil conductors; and a capacitor portion formed by stacking a plurality of insulating layers and a plurality of capacitor conductors. In the laminated noise filter, the coil conductor is electrically connected to form a coil having an axis parallel to a stacking direction of the laminate and a mounting surface of the laminate, and a capacitor is formed by the capacitor conductor. When the length of the stacked body in the stacking direction is defined as a length dimension L and the dimension in a direction perpendicular to the stacking direction is defined as a width dimension W, the condition of W> L is satisfied. And a laminated noise filter. 2. A ladder-type circuit in which the coil unit and the capacitor unit are alternately stacked two each and the coil of the coil unit is used as a series element, and the capacitor of the capacitor unit is used as a parallel element, The permeability of one of the two coil portions is made higher than the permeability of the other coil portion, and the permittivity of one of the two capacitor portions is changed to the permittivity of the other capacitor portion. 2. The multilayer noise filter according to claim 1, wherein the noise filter is higher. 3. The multilayer noise filter according to claim 1, wherein the capacitor is a feedthrough capacitor.