JPH06325939A - Inductor - Google Patents

Abstract

PURPOSE:To provide a inductor capable of obtaining a large inductance even if a dielectric material or an insulator material is used as the material of a laminated body yet lessening the effect of the title inductor from a magnetic field on the other parts. CONSTITUTION:The inductor 10 includes a laminated body comprising a dielectric e.g. a ceramics etc. At this time, coils 40a, 40b are formed inside the laminated body. Besides, the circular trenches 42a in larger diameter than that of the coils 40a are formed around the coils 40a of the laminated body while the other circular trenches 42b in larger diameter than that of the coils 42b are formed around the coils 40b. Furthermore, the cylindrical bodies 44a, 44b comprising magnetic bodies are arranged inside the trenches 42a, 42b.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inductor, and more particularly, to an inductor including a laminated coil in which a coil is formed in a laminated body.

[0002]

2. Description of the Related Art Some conventional inductors are formed by embedding a coil conductor in a laminate forming a multilayer substrate. Especially in the case of a multi-layer substrate, a dielectric or an insulating ceramic is used as a material for the laminated body,
Since the magnetic permeability was low, the obtained inductance was small. Therefore, in order to obtain a large inductance with this inductor, the length of the coil conductor has to be lengthened, which makes it difficult to reduce the size.

Therefore, it is conceivable to use a magnetic material in the portion where the inductor is to be formed and form an inductor having a large inductance in a multilayer substrate using a dielectric material. In such an inductor, since the magnetic permeability of the inductor forming portion is high, a large inductance can be obtained. However, when a dielectric ceramic material and a magnetic ceramic material are mixed and attempted to be integrally fired, because of the difference in the sintering characteristics of these materials,
There are many restrictions, such as the materials used, and the characteristics are often unsatisfactory. Therefore, it is conceivable to use only a magnetic material in order to obtain a large inductance, but it is not suitable as a material for the multilayer substrate.

Further, when the inductor is applied to a high frequency circuit, the electrostatic capacity formed between coil conductors is utilized. In this case, an LC component is formed by the inductance obtained by the inductor and the capacitance between the coil conductors, and this LC component is used as a filter or the like. However, in an inductor using a magnetic material, the capacitance formed between coil conductors is small, and it is almost useless.

Further, in order to obtain a large inductance, an inductor in which a core made of a magnetic material is arranged at the center position of the coil conductor in the multilayer substrate is considered. Figure 6
(A) is an exploded perspective view showing such an inductor 1, and FIG. 6 (B) is a sectional schematic view thereof. The inductor 1 includes a laminated body 2. The laminated body 2 is formed by laminating sheets made of, for example, a dielectric ceramic material and firing them. The laminate 2 includes layers 3a-3d, and layers 3a-3
Planar C-shaped conductive lines 4a to 4c are formed on the main surface of c. One ends of the conductive lines 4 a and 4 b are drawn out to both ends of the laminated body 2 and connected to the external electrodes 9. These conductive lines 4a to 4c are connected to each other via the via holes 5 formed in the layers 3b and 3c, so that the laminated body 2 is formed.
A spiral coil 6 is formed inside. A hole 7 is formed in the thickness direction of the laminated body 2 at the center of the coil 6 of the laminated body 2 thus formed. A rod-shaped core 8 made of a magnetic material such as ferrite is arranged in the hole 7.
In this inductor 1, since the core 8 made of a magnetic material is arranged at the center of the coil 6, a large inductance can be obtained.

[0006]

However, in these inductors, the magnetic field generated in many cases covers a wide range around the inductor regardless of the material of the laminated body. Due to such an influence of the magnetic field, there is a problem that other parts cannot be brought close to the inductor and it is difficult to downsize the circuit. In particular, when two or more inductors are formed in the same multilayer substrate, it is necessary to separate them in order to prevent them from being inductively coupled, which causes a problem that the multilayer substrate becomes large.

Therefore, the main object of the present invention is to obtain a large inductance even when a dielectric material or an insulating material is used as the material of the laminated body, and yet to prevent the influence of the magnetic field from the inductor on other parts. An object is to provide an inductor that can be made small.

[0008]

According to the present invention, there is provided a laminated body formed of an insulating material, a coil formed in the laminated body,
An inductor, which is formed of a material having a magnetic permeability higher than that of the material of the laminated body, and includes a tubular body arranged in the laminated body so as to surround the periphery of the coil.

[0009]

The tubular body made of a material having a high magnetic permeability is arranged so as to surround the coil. Therefore,
The magnetic flux generated by the coil mainly passes through the tubular body.

[0010]

According to the present invention, since most of the magnetic flux passes through the tubular body, the magnetic flux leaking to the outside of the tubular body can be reduced, and the generated magnetic flux can be effectively utilized. You can Therefore, even when two or more inductors are formed in the same multilayer substrate, they are less likely to be inductively coupled to each other, and the multilayer substrate can be downsized. In addition, other components that are easily affected by the magnetic field can be arranged close to the inductor, and the circuit using the inductor can be downsized. Further, according to the present invention, since a large inductance can be obtained by effectively utilizing the magnetic flux, it is possible to use a dielectric material or an insulating ceramic material for the laminated body. Further, since the laminated body can be formed of a single material, it is not necessary to consider the difference in sintering characteristics and the like, and the range of selection of materials can be expanded.

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

[0012]

1 is a perspective view showing an inductor of the present invention, and FIG. 2 is an exploded perspective view thereof. In addition, FIG.
It is a cross-sectional schematic diagram of the inductor shown in FIG. Inductor 10
Includes a stack 12. The stack 12 includes a first layer 14. On one end side in the longitudinal direction of the one main surface of the first layer 14,
The spiral first conductive line 16a is formed. The conductive line 16a is formed so as to extend counterclockwise from one end thereof, for example, three quarters. A via hole 18a is formed at one end of the conductive line 16a. The conductive line 16a is connected to the first layer 1 through the via hole 18a.
4 is connected to the external electrode 20a formed on the other main surface. A spiral first conductive line 16b is formed on the other end side of the one main surface of the first layer 14 in the longitudinal direction. The conductive line 16b is counterclockwise from one end thereof,
For example, it is formed so as to make three quarters. A via hole 18b is formed at one end of the conductive line 16b. The conductive line 16b is connected to the external electrode 20b formed on the other main surface of the first layer 14 through the via hole 18b.

A second layer 22 is formed on the first layer 14. A spiral second conductive line 24a is formed on one longitudinal end of the one main surface of the second layer 22.
One end of the conductive line 24a is formed at a position corresponding to the other end of the first conductive line 16a, and is formed so as to extend counterclockwise from that position, for example, three quarters. Then, a via hole 26a is formed at one end of the second conductive line 24a. One end of the second conductive line 24a and the other end of the first conductive line 16a are connected via this via hole 26a. In addition, a spiral second conductive line 24b is formed on the other end side in the longitudinal direction of the one main surface of the second layer 22. One end of the conductive line 24b is formed at a position corresponding to the other end of the first conductive line 16b, and counterclockwise from that position, for example, three quarters.
It is formed so as to go around. And the second conductive line 2
A via hole 26b is formed at one end of 4b.
The second conductive line 24 passes through the via hole 26b.
One end of b and the other end of the first conductive line 16b are connected.

A third layer 28 is formed on the second layer 22. A spiral third conductive line 30a is formed on one longitudinal end of the one main surface of the third layer 28.
One end of the conductive line 30a is formed at a position corresponding to the other end of the second conductive line 24a, and is formed counterclockwise from that position so as to make, for example, three quarters. A via hole 32a is formed at one end of the third conductive line 30a. One end of the third conductive line 30a and the other end of the second conductive line 24a are connected via this via hole 32a. A spiral third conductive line 30b is formed on the other end side of the one main surface of the third layer 28 in the longitudinal direction. One end of the conductive line 30b is formed at a position corresponding to the other end of the second conductive line 24b, and counterclockwise from that position, for example, three quarters.
It is formed so as to go around. And the third conductive line 3
A via hole 32b is formed at one end of 0b.
The third conductive line 30 is provided through the via hole 32b.
One end of b and the other end of the second conductive line 24b are connected.

A fourth layer 34 is formed on the third layer 28. A strip-shaped external electrode 36a is formed on one longitudinal end of the one main surface of the fourth layer 34. External electrode 3
The via hole 38a is formed in the third conductive line 30a.
It is formed at a position corresponding to the other end of a. The external electrode 36a and the third conductive line 3 are connected through the via hole 38a.
0a is connected. A strip-shaped external electrode 36b is formed on the other end side of the one main surface of the fourth layer 34. A via hole 38b is formed in the external electrode 36b at a position corresponding to the other end of the third conductive line 30b. The external electrode 36b and the third conductive line 30b are connected via the via hole 38b.

These layers 14, 22, 28 and 34 are laminated and integrated to form a laminated body 12. The coil 40a is formed by the conductive lines 16a, 24a, 30a therein, and the conductive lines 16b, 24a, 24a
A coil 40b is formed by b and 30b.

A circular groove 42a having a larger diameter than the coil 40a is formed around the coil 40a of the laminate 12, and a circular groove 42b having a larger diameter than the coil 40b is formed around the coil 40b. It The groove 42a and the groove 42b are formed in the thickness direction of the laminated body 12, respectively. Then, a cylindrical tubular body 44a is arranged in the groove 42a, and a cylindrical tubular body 44b is arranged in the groove 42b. The tubular body 44a and the tubular body 44b are formed by molding a magnetic material such as ferrite into a hollow cylindrical shape,
It is formed by firing.

In order to manufacture such an inductor 10, first, a plurality of sheets 46 made of, for example, a dielectric ceramic material are prepared. Next, as shown in FIG. 4A, a conductive material 48 such as a conductive paste is printed on each sheet 46 in the shape of each conductive line or external electrode, and each via hole for connecting them is formed. It is formed. Then, the conductive material 48 is filled in each via hole. The external electrodes may be formed after firing the laminate described below.

Next, each sheet 4 on which the conductive material 48 is printed
6 are stacked. The laminated sheets 46 are fired,
As shown in FIG. 4B, the laminated body 12 has the coils 40a and 40b inside. Next, as shown in FIG. 4C, a circular groove 42a is formed around the coil 40a in the thickness direction of the laminated body 12 by, for example, a drill. Similarly, a circular groove 42b is formed around the coil 40b. Then, the cylindrical tubular body 44a is housed in the groove 42a, the cylindrical tubular body 44b is housed in the groove 42b, and the inductor 10 shown in FIG. 1 is formed.

In such an inductor 10, since the coils 40a and 40b are formed in the laminated body 12 made of a dielectric or an insulator, the capacitance generated between the conductive lines in the thickness direction of the laminated body 12 is utilized. be able to. In addition, a cylindrical body 44 made of a magnetic material is provided around the coils 40a and 40b.
Since a and 44b are arranged, the coils 40a and 40
A portion having a high magnetic permeability is formed around b. Therefore, most of the magnetic flux generated in the coils 40a and 40b passes through the tubular bodies 44a and 44b, and the leakage flux to the outside of the tubular bodies 44a and 44b is reduced. Therefore, the coil 4
The magnetic flux generated in 0a and 40b can be effectively used, and a large inductance can be obtained without increasing the number of coil turns.

Further, since the magnetic flux is absorbed by the cylindrical bodies 44a and 44b, the inductive coupling generated between the plurality of inductors can be reduced. Therefore, the laminated body 12
Even when a plurality of coils are formed inside, the distance between the coils can be reduced, so that the inductor 10 can be downsized. Further, even when the inductor 10 and the other component are used, the inductor 10 and the other component can be brought close to each other, which enables high-density mounting. Furthermore, since the laminated body 12 can be formed of only a single material, it is not necessary to consider the difference in sintering characteristics and the like, and the range of selection of materials can be expanded. Therefore, the material is not limited, and a material having excellent characteristics can be used.

FIG. 5A is a schematic sectional view showing a modification of the inductor of the present invention. In the inductor 10 shown in FIG. 5A, a cylindrical body 44 is arranged around the coil 40, and a cylindrical core 46 made of a magnetic material is arranged at the center of the coil 40. In this case, a larger inductance can be obtained.

FIG. 5B is a schematic sectional view showing another modification of the inductor of the present invention. In the inductor 10 shown in FIG. 5B, a disc-shaped lid member 48 made of a magnetic material is formed in one opening of a cylindrical tubular body 44, and is integrally molded. In this case, the leakage of magnetic flux from the inductor 10 can be further reduced.

FIG. 5C is a schematic sectional view showing still another modified example of the inductor of the present invention. In the inductor 10 shown in FIG. 5C, a cylindrical body 44 is arranged around the coil 40, and a cylindrical core 46 made of a magnetic material is arranged at the center of the coil 40. Cylindrical body 44 and core 4
6 are integrally formed by connecting one ends thereof with a disc-shaped lid member 48 made of a magnetic material.

FIG. 5D is a schematic sectional view showing another modification of the inductor of the present invention. In the inductor 10 shown in FIG. 5D, the grooves 4 formed on both main surfaces of the laminate 12 are used.
Two tubular bodies 44 are inserted into the 2 from above and below. Tubular body 4
Reference numeral 4 denotes a cylindrical member made of a magnetic material, and a disc-shaped lid member 48 made of a magnetic material is formed at one of the openings of the magnetic member and integrally molded.

FIG. 5 (E) is a schematic sectional view showing still another modification of the inductor of the present invention. In this inductor 10, the insertion amount of the tubular body 44 can be adjusted by a method such as forming a screw in the groove 42 and the tubular body 44 of the laminated body 12. With this configuration, the inductance can be adjusted by adjusting the insertion amount of the tubular body 44. These modified examples also have the same effects as the embodiment shown in FIG.

The substrate for forming the laminated body is not limited to the one formed of a dielectric or an insulator, but may be formed of a magnetic substance. In that case, a material having a magnetic permeability higher than that of the laminated body is used as the material of the tubular body. Then, with such an inductor, a larger inductance can be obtained. Further, the laminated body is not limited to one formed by laminating four layers, and may be one formed by laminating one, two or three layers.
It may be formed by laminating one or more layers. The laminated body is not limited to stacking sheets and may be printed and laminated. Further, two conductive lines for forming the coil are formed on the main surface of the substrate, but the number of conductive lines is not limited to this and may be one or more. Further, although the spiral direction of the coil is formed counterclockwise from below, the spiral direction is not limited to this and may be formed clockwise. Further, although the two coils are formed so that the spiral directions are the same, the present invention is not limited to this, and the spiral directions may be reversed. Further, in order to adjust the inductance, the tubular body of the inductor shown in FIG. 1 may be trimmed.

[Brief description of drawings]

FIG. 1 is a perspective view showing an inductor of the present invention.

FIG. 2 is an exploded perspective view of the inductor shown in FIG.

FIG. 3 is a schematic sectional view of the inductor shown in FIG.

4A is a perspective view of a sheet for forming the inductor shown in FIG. 1, FIG. 4B is a perspective view of a laminated body obtained by laminating and firing the sheets, and FIG. It is a perspective view which shows the state in which the groove | channel was formed in the body.

5A is a cross-sectional schematic view showing a modified example of the inductor of the present invention, FIG. 5B is a cross-sectional schematic view showing another modified example, and FIG. 5C is a further modified example. It is sectional drawing solution figure, (D) is sectional drawing solution figure which shows another modification,
(E) is a sectional view showing a further modified example.

FIG. 6A is an exploded perspective view showing an example of a conventional inductor which is a background of the present invention, and FIG. 6B is a cross-sectional schematic view thereof.

[Explanation of symbols]

 10 inductor 12 laminated body 20a, 20b external electrode 36a, 36b external electrode 38a, 38b via hole 40a, 40b coil 42a, 42b groove 44a, 44b tubular body

Claims (1)

[Claims] 1. A laminated body formed of an insulating material, a coil formed in the laminated body, and a material having a magnetic permeability higher than that of the material of the laminated body, and the coil surrounding the coil. An inductor including a tubular body disposed within a stack.