JP3087648B2 - Laminated LC filter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a multilayer LC filter, and more particularly to a multilayer LC filter for removing noise radiated from high-frequency electronic equipment.

[0002]

2. Description of the Related Art As a conventional laminated type LC filter, for example, as shown in FIG. 8, inductors 51 and 52 formed by laminating a plurality of coil conductors and magnetic layers, and a portion between the inductors 51 and 52 are provided. And a capacitor section 53 sandwiched between them. FIG. 8 shows a coil 5 formed by electrically connecting a plurality of coil conductors.
4 and 55 are schematically displayed in the inductor sections 51 and 52, respectively. The axial directions of the coils 54 and 55 are parallel to the external electrodes 61, 62, 63 and 64, and the lamination direction of the coil conductor and the magnetic layer is also parallel to the external electrodes 61 to 64. Note that, in FIG.
Are omitted.

[0003]

However, in the conventional multilayer LC filter, large floating capacitances are generated between the coils 54 and 55 and the external electrodes 61 to 64 in a distributed manner. These large stray capacitances are
5 are formed electrically in parallel. Therefore, the effect of the stray capacitance cannot be ignored, and there is a problem that the insertion loss characteristics of the LC filter deteriorate in a high frequency range.

The external electrodes 61 and 62 are connected to coils 55 and 5 exposed at end faces of the inductors 52 and 51, respectively.
4 and is electrically connected to the coils 55 and 54. However, if the exposed areas of the lead portions of the coils 54 and 55 are small, there is a possibility that sufficient connection reliability may not be obtained. Accordingly, an object of the present invention is to provide a laminated LC filter having excellent insertion loss characteristics in a high frequency range and having high reliability in connection between an external electrode and a coil.

[0005]

In order to achieve the above object, a laminated LC filter according to the present invention comprises a coil formed by electrically connecting coil conductors to each other through a relay opening. An end of the coil is electrically connected to an external electrode through a lead-out opening, an axial direction of the coil is perpendicular to the external electrode, and a laminating direction of the coil conductor and the magnetic material layer Are perpendicular to the external electrode, and the area of the lead-out opening is larger than the area of the relay opening. Here, a via hole or the like is specifically used as the relay opening or the lead-out opening.

[0006]

According to the above configuration, since the axial direction of the coil is perpendicular to the external electrode, the stray capacitance generated between the coil and the external electrode is reduced. This is because the potential difference between the coil and the external electrode is small and the distance between the two is wide. Since the area of the lead-out opening is larger than the area of the relay opening, the connection area between the external electrode and the coil is increased.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a laminated LC filter according to the present invention will be described with reference to the accompanying drawings. As shown in FIG. 1, the multilayer LC filter 1 has a structure in which a capacitor section 4 is sandwiched between inductor sections 2 and 3. Input external electrodes 5 and output external electrodes 6 are provided on the left and right side surfaces of the filter 1, respectively, and ground external electrodes 7 and 8 are provided on the front and rear side surfaces, respectively.

As shown in FIG. 2 (schematically shown), in the filter 1, the axial directions of the coils 16 and 17 incorporated in the inductor portions 2 and 3 are perpendicular to the external electrodes 5 and 6. One ends of the coils 16 and 17 are electrically connected to the input external electrode 5 and the output external electrode 6, respectively. Further, the structure of the filter 1 will be described in detail with reference to FIGS.

As shown in FIG. 3, the inductor section 2 includes a magnetic sheet 12 provided with coil conductors 15a, 15b, 15c, and 15d and relay via holes 22a, 22b, 22c, and 22d, respectively, and lead-out via holes 21a and 2d.
1b, a magnetic sheet 12 provided with a relay via hole 22e, and the like. The magnetic sheet 12 is a sheet obtained by kneading magnetic powder such as ferrite with a binder or the like.

The diameters of the extraction via holes 21a and 21b are set to be larger than the diameters of the relay via holes 22a to 22e. Specifically, for example, the draw-out via hole 21
The diameters of a and 21b are designed to be 200 to 300 μm, and the diameters of the relay via holes 22a to 22e are designed to be 100 to 200 μm. Since the relay via holes 22a to 22d are provided on the same sheet 12 together with the coil conductors 15a to 15d, respectively, the relay via holes 22a to 22d
Area is limited, and the relay via holes 22a to 22a
The increase in the diameter of 2d is restricted. On the other hand, since the draw-out via holes 21a and 21b have no other conductors or the like provided on the surface of the sheet 12, the increase in the diameter can be performed without being restricted (for the same reason, described later). The diameters of the lead-out via holes 21c and 21d can also be increased.

As shown in FIG. 4, the capacitor section 4 includes a dielectric sheet 13 provided with coil conductors 15e and 15g, a dielectric sheet 13 provided with capacitor electrodes 16a and 16c, a coil conductor 15f, and a coil conductor 15f. A dielectric sheet 13 provided with a capacitor electrode 16b electrically connected to the center of the relay via hole 15f.
2h, 22j, 221 and 22n, respectively. Capacitor electrode 16
One end of each of a and 16c is exposed on the near side of the sheet 13, and the other end is exposed on the back side of the sheet 13. The dielectric sheet 13 is a sheet obtained by kneading a dielectric powder with a binder or the like.

As shown in FIG. 5, the inductor portion 3 includes a magnetic sheet 12 provided with coil conductors 15h, 15i, 15j, 15k and relay via holes 22r, 22s, 22t, 22u, respectively, and draw-out via holes 21c, 2c.
1d, a magnetic sheet 12 provided with relay via holes 22q, and the like. The diameters of the extraction via holes 21c and 21d are set to be larger than the diameters of the relay via holes 22q to 22u.

An intermediate insulator sheet 14 is provided between the inductor section 2 and the capacitor section 4 and between the inductor section 3 and the capacitor section 4, respectively. The intermediate insulator sheet 14 prevents peeling and cracking due to the difference between the thermal expansion coefficients of the inductors 2 and 3 and the capacitor 4. For this reason, the intermediate insulator sheet 14 is formed into a sheet by kneading, for example, a mixed powder of a magnetic substance and an insulator together with a binder or the like.

The coil conductors 15a to 15f (note that the coil conductor 15f is the lower half) are
Are electrically connected in series via relay via holes 22a to 22j provided in
6 is formed. The coil conductors 15f to 15k (however, the coil conductor 15f is the upper half) are
4 are electrically connected in series via the relay via holes 22k to 22t respectively provided in the coil 4 to form the solenoid-shaped coil 17.

The capacitor electrode 16b is opposed to the capacitor electrodes 16a and 16c.
The capacitors 18 are formed by 6a to 16c. The coil conductors 15a to 15k and the capacitor electrodes 16a to 16c
Sheet 1 made of Ag, Pd, Ag-Pd, Cu, etc.
It is formed on the surfaces of 2, 13, and 14 by a known printing method, a sputtering method, a vacuum deposition method, or the like.

The sheets 12, 13, and 14 are stacked and integrally sintered to form a laminate having a structure in which the capacitor portion 4 is sandwiched between the inductor portions 2 and 3 shown in FIG. Next, input external electrodes 5 and output external electrodes 6 are formed on the left and right side surfaces of the laminate, respectively, and ground external electrodes 7 and 8 are formed on the front side and the rear side of the laminate, respectively. You. These external electrodes 5 to 8 are formed by means such as sputtering, vacuum deposition, printing and printing.

The input external electrode 5 is connected to the extraction via hole 2.
It is electrically connected to one end of the coil 16, specifically, the end of the coil conductor 15a via 1a and 21b. The output external electrode 6 is connected to the extraction via holes 21c and 2c.
Through 1d, it is electrically connected to one end of the coil 17, specifically, the end of the coil conductor 15k. Further, the ground external electrode 7 is connected to the capacitor electrodes 16a, 16a.
c, and the ground external electrode 8 is electrically connected to the other end of each of the capacitor electrodes 16a, 16c. FIG. 6 is an electric equivalent circuit diagram of the LC filter 1.

In the LC filter 1 thus obtained, the stacking direction of the sheets 12, 13, 14 is perpendicular to the external electrodes 5 to 8, and the axial direction of the coils 16, 17 is relative to the external electrodes 5, 6. It is vertical. Therefore, the coils 16, 1
The stray capacitance generated in a distributed manner between the external electrode 5 and the external electrodes 5 to 8 is between the coil 16 and the input external electrode 5 and the coil 1
Since the potential difference between the external electrode 7 and the output external electrode 6 is small, and the distance between the coil 16 and the output external electrode 6 and the distance between the coil 17 and the input external electrode 5 are wide, they are extremely small. As a result, the effect of the stray capacitance can be ignored in practical use, and the LC filter 1 having excellent insertion loss characteristics in a high frequency range can be obtained.

Further, the input external electrode 5 and the coil 16
Are electrically connected through the via holes 21a and 21b having a large diameter, so that the connection area between the input external electrode 5 and the coil 16 is increased, so that the connection reliability is improved, and The DC resistance connected to the coil 16 can be reduced. For the same reason, the connection reliability between the output external electrode 6 and the coil 17 can be improved and the connection DC resistance can be reduced.

The laminated LC filter according to the present invention is not limited to the above embodiment, but can be variously modified within the scope of the invention. In the embodiment,
The electrical connection between the external electrode and the coil is performed using two sheets provided with the via holes for extraction, but the via holes for extraction directly connected to the external electrodes are left with a large diameter.
The diameter of the other via hole for extraction may be equal to the diameter of the via hole for relay.

The capacitor portion may be formed by laminating a plurality of dielectric sheets provided with only relay via holes. In this case, by connecting the relay via holes, a distributed capacitance is formed between the via conductor formed in the capacitor portion and the ground external electrode, and a capacitor is obtained. Alternatively, the capacitor section may be formed by laminating a plurality of dielectric sheets provided with only capacitor electrodes and relay via holes. Further, in the embodiment, for example, as shown in FIG.
It may be configured by laminating a plurality of dielectric sheets 13 provided with the coil conductor 15g and the internal ground electrode 30 close to the coil conductor 15g. In this case, the internal ground electrode 30 is electrically connected to the ground external electrode 7, and the coil conductor 15g is connected in series via a relay via hole 22o or the like to form a solenoid-shaped coil in the capacitor section. Then, a distributed capacitance is formed between the solenoid-shaped coil and the internal electrode 30 to obtain a capacitor.

In the above embodiment, the inductor section
Although the description has been given of the one composed of the capacitor part and the inductor part, L
It may be a C filter, an LC filter composed of an inductor section, a capacitor section, an inductor section, a capacitor section, and an inductor section. Further, an LC composite component in which a resistor is built in the capacitor portion, or a new insulator layer is laminated and a resistor is built in the insulator layer may be used.

In the above embodiment, the magnetic sheet and the dielectric sheet on which the conductors are formed are stacked and then integrally fired, but the present invention is not necessarily limited to this. The sheet may be a sheet sintered in advance. Further, an LC filter may be created by a manufacturing method described below. After a paste-like magnetic material is applied by printing or the like to form a magnetic layer, a paste-like conductive material is applied to the surface of the magnetic layer to form an arbitrary conductor. Next, a paste-like magnetic material is applied over the conductor to form a magnetic layer in which the conductor is embedded. Similarly, a dielectric layer containing a conductor is formed on the magnetic layer. In this way, an LC filter having a laminated structure can be obtained by successively coating.

The equivalent circuit of the obtained LC filter is not limited to the T type, but may be a π type or an L type.

[0025]

As is apparent from the above description, according to the present invention, since the axial direction of the coil is perpendicular to the external electrode, the stray capacitance generated between the coil and the external electrode can be minimized. A laminated LC filter having excellent insertion loss characteristics in a high frequency range can be obtained. And since the area of the drawer opening is set larger than the area of the relay opening, the connection reliability between the external electrode and the coil is improved, and
The connection DC resistance between the external electrode and the coil can be reduced.

[Brief description of the drawings]

FIG. 1 is a perspective view showing the appearance of a laminated LC filter according to the present invention.

FIG. 2 is an internal perspective view of the laminated LC filter shown in FIG. 1;

FIG. 3 is an exploded perspective view of one inductor section of the multilayer LC filter shown in FIG. 1;

FIG. 4 is an exploded perspective view of a capacitor section of the multilayer LC filter shown in FIG. 1;

FIG. 5 is an exploded perspective view of the other inductor part of the multilayer LC filter shown in FIG. 1;

6 is an electric equivalent circuit diagram of the laminated LC filter shown in FIG.

FIG. 7 is a perspective view of a dielectric sheet showing another embodiment.

FIG. 8 is an internal perspective view of a conventional laminated LC filter.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... LC filter 2, 3 ... Inductor part 4 ... Capacitor part 5 ... Input external electrode 6 ... Output external electrode 7, 8 ... Ground external electrode 12 ... Magnetic material sheet 15a-15k ... Coil conductor 16, 17 ... Coil 21a-21d … Drawer via holes 22a to 22u… Relay via holes

────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Toshimi Kaneko 2-26-10 Tenjin, Nagaokakyo-shi, Kyoto Murata Manufacturing Co., Ltd. (56) References JP-A-8-55726 (JP, A) JP-A Heihei JP-A-3-225905 (JP, A) JP-A-6-275466 (JP, A) JP-A-6-69040 (JP, A) JP-A-2-202006 (JP, A) JP-A-2-165608 (JP, A A) (58) Field surveyed (Int. Cl. ⁷ , DB name) H01F 17/00 H01F 41/04 H01G 4/40 H01H 7/01

Claims (7)

(57) [Claims] 1. A laminated LC filter comprising: an inductor portion formed by laminating a plurality of coil conductors and a magnetic material layer; and a capacitor portion laminated on the inductor portion, wherein the coil conductors are relay via holes. A coil is formed by being electrically connected to the input / output external electrode, and the end of the coil is electrically connected to the input / output external electrode via a lead-out via hole, and the axial direction of the coil is connected to the input / output external electrode. Vertical, and the lamination direction of the coil conductor and the magnetic layer is perpendicular to the input / output external electrode, the diameter of the extraction via hole is larger than the diameter of the relay via hole , and A laminated LC filter characterized by being three times or less . 2. A method of laminating a plurality of coil conductors and a magnetic layer.
The configured inductor portion and the inductor portion
In a multilayer LC filter with a capacitor part
And electrically connect the coil conductors to each other via a relay via hole.
To form a coil and pull out the end of the coil
Electrically connected to input / output external electrodes via
And the axial direction of the coil corresponds to the input / output external electrode.
Perpendicular to the coil conductor and the magnetic layer
Vertical to the input / output external electrodes,
The diameter of the via hole for drawing is set to the diameter of the relay via hole.
Larger and 3 times or less, and the drawer
A hole is formed by connecting multiple via holes of different diameters
And a via connected to the input / output external electrode
The diameter of the via hole is connected to the end of the coil.
Laminated LC fill characterized by being larger than the diameter
Ta. 3. A method in which a plurality of coil conductors are laminated.
A conductor laminated on the inductor section and the inductor section;
In the stacked LC filter including a support portion, the carp
Conductors are electrically connected to each other via relay via holes.
To form a coil, and pull out the end of the coil via
When electrically connected to input / output external electrodes via
The axial direction of the coil with respect to the input / output external electrodes.
Vertical, and the stacking direction of the coil conductor
Perpendicular to the external electrode
Is larger than the diameter of the relay via hole and at least three times
Multilayer LC filter, characterized in that down. 4. The method according to claim 1, wherein the extraction via hole is provided in the coil.
Characterized by being provided parallel to the axial direction
The multilayer LC filter according to claim 1. 5. The method according to claim 1, wherein said inductor section and said capacitor section have
Intermediate insulator consisting of mixed powder of magnetic material and insulator
3. A method according to claim 1, wherein a layer is provided.
The multilayer LC filter according to claim 4. 6. The method according to claim 1, wherein said inductor portion and said capacitor portion are connected to each other.
Outside the input and output at both ends of the laminated body
Electrodes are provided on both sides of the laminate.
External electrodes are provided respectively within the capacitor section.
Via conductor formed by connecting relay via holes provided in
And the distributed capacitance formed between the
2. The capacitor according to claim 1, wherein
A multilayer LC filter according to claim 5. 7. A plurality of coil conductors in said capacitor section.
The body is electrically connected via a relay via hole to form a coil.
And provided close to the coil and the coil conductor.
With the distributed capacitance formed between the internal ground conductor
The capacitor according to claim 1 or 2, wherein the capacitor is configured.
The multilayer LC filter according to claim 5.