JP2002190411A - Chip inductor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a chip inductor which can obtain high inductance, while its external dimensions is reduced as much as possible. SOLUTION: This chip inductor 1 is provided with an inductor body 10 formed by winding a conductor pattern 13 around a rectangular plate-like core 11 composed of a magnetic material via an insulation layer 12 from an upper surface 11u to a lower surface 11l of the core 11 and a yoke 20 which surrounds at least three sides of the core 10, and at the same time, is coupled with the facing two sides of the core 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chip inductor for a small electronic component mounted on a surface.

[0002]

2. Description of the Related Art For example, with the recent downsizing, higher integration, and higher frequency of electronic devices such as mobile phones, a circuit structure which is smaller and can be surface-mounted is desired. Development of an inductance component for forming a circuit structure, that is, a chip inductor, has been advanced.

FIG. 9 illustrates a conventional chip inductor. A chip inductor A shown in FIG.
The chip inductor B is configured by winding a winding Ab around a chip-shaped core Aa, and a chip inductor B shown in FIG.
A meandering conductor pattern B is provided on one surface of a chip-shaped core Ba.
b.

[0004]

By the way, in the winding type chip inductor A shown in FIG. 9A, when increasing the inductance, the number of turns of the winding must be increased. Due to this, the wire diameter of the winding cannot be extremely thinned, so that it has been difficult to reduce the size while achieving high inductance.

[0005] Further, in the planar type chip inductor B shown in FIG.
Although it is possible to greatly reduce the size as compared with the above, since the length of the conductor pattern Bb is restricted by the area of one surface of the core Ba, it is difficult to obtain a desired high inductance. Even if the conductor patterns are formed narrowly and at small intervals, it has been difficult to sufficiently cope with the high functionality and high frequency of recent electronic devices.

The present invention has been made in view of the above circumstances, and has as its object to provide a chip inductor capable of obtaining high inductance while achieving as small a size as possible.

[0007]

In order to achieve the above object, a chip inductor according to the present invention comprises a rectangular plate-shaped core made of a magnetic material, and a conductor pattern formed on an upper surface and a lower surface of the core by an insulating layer. And an yoke that surrounds at least three sides of the core and is coupled to two opposing sides of the core.

[0008]

Embodiments of the present invention will be described below in detail with reference to the drawings. As shown in FIGS. 1 and 2,
The chip inductor 1 according to the embodiment includes an inductor body 10 and a yoke 20.

As shown in FIGS. 1 and 3, the inductor body 10 has a rectangular plate-shaped core 11 made of a magnetic material such as electromagnetic steel or the like with an insulating layer 12 made of an insulating material such as an epoxy resin or a polyimide resin interposed therebetween. Thus, the conductive pattern 13 is formed.

The conductor pattern 13 is formed in such a manner that the entire circumference of the core 11 is wound like a coil over the upper surface 11u and the lower surface 11l of the core 11. Terminal pads 13P are formed on both ends of the conductor pattern 13, respectively. Each terminal pad 13P is formed on the lower surface 11l of the core 11, that is, on the mounting surface of the chip inductor 1.

An example of a method for manufacturing the above-described inductor body 10 will be described below. First, as shown in FIG.
An insulating layer (about 10 μm) 12 made of an insulating material such as epoxy resin is formed on the entire surface of a core 11 made of a 2 mm thick electromagnetic steel sheet or the like, and then, as shown in FIG. A metal layer (about 10 to 20 μm) M made of a metal material such as copper,
4 (c), a photosensitive resist is applied to the entire surface of the metal layer M to form a resist layer R. Then, as shown in FIG.

Thereafter, by exposing and developing the resist layer R and patterning it, a resist pattern RP is formed on the upper and lower surfaces of the core 11 as shown in FIG. Here, first, the resist layer R on the upper surface and then the resist layer R on the lower surface are patterned.
By patterning the resist layer R on the upper surface and the lower surface by forming a shape protruding on the side surface of the core 11, a predetermined resist pattern (not shown) is formed on both side surfaces of the core 11. It is not necessary to prepare a dedicated exposure mask for patterning in any way.

After a resist pattern RP is formed on the surface (upper surface, lower surface, and side surface) of the core 11, the core 11 is immersed in a solution to etch the metal layer M, thereby forming a conductor as shown in FIG. By forming the pattern 13 and then removing the resist layer R, the inductor body 10 is completed as shown in FIG.

After the metal layer M is formed as shown in FIG. 4B, the metal layer M may be laser-processed to form the conductor pattern 13 or the surface of the insulating layer 12 may be formed. It is also possible to form the conductor pattern 13 by plating directly.

In the inductor body 10 having the structure described above, since the conductor pattern 13 is formed in a manner of winding the entire circumference of the core 11 like a coil, a conventional chip inductor formed by winding a winding around the core is used. In addition to achieving a significant reduction in size as compared with the above, the entire length of the conductor pattern 13 can be set longer than that of a conventional chip inductor in which a conductor pattern is formed on one surface of a core.

On the other hand, as shown in FIGS. 1 and 2, the yoke 20 is a U-shaped thin plate made of a magnetic material such as electromagnetic steel, like the core 11, and the two ends of the core 11 facing each other are opposed to each other. It is connected to the parts 11e, 11e.

The yoke 20 is connected to the end 11 of the core 11.
e, 11e and edge portions 20A, 20A facing the core 1
1 extends along one side 11 s,
A and 20A are connected to each other, and side edges 20B are connected to each other. Ends 20A and 20A of the yoke 20 are connected to ends 11e and 11e of the core 11, respectively.

Here, as shown in FIGS. 5 (a) to 5 (d), the through hole 20o formed in the edge 20A of the yoke 20 is press-formed on the edge 11e of the core 11 in the inductor body 10. By fitting the half blanking protrusion 10s, the inductor body 10 and the yoke 20 are caulked to each other.

It is needless to say that the inductor body 10 and the yoke 20 are mechanically and electrically joined by the above-described caulking connection. The caulking joint made up of the combination of the half blanking projection 10 s and the through hole 20 o as described above is provided at the end 11 e of the core 11 and the yoke 2.
It is possible to set any number of one or more locations between each of the zero edge portions 20A.

Here, the inductor body 10 and the yoke 20
6 (a) to 6 (d), as shown in FIGS. 6 (a) to 6 (d), a pin 20p formed in an end portion 20A of the yoke 20 is inserted into a through hole 10h formed in an edge 11e of the core 11 in the inductor body 10. And the tip of the pin 20p is crushed by the punch P, so that the inductor body 10 and the yoke 20 can be caulked to each other.

Further, as shown in FIG.
An appropriate gap S is defined between the side edge 11s of the core 11 at 0 and the side edge 20B of the yoke 20 for the purpose of preventing a short circuit between the conductor pattern 13 and the yoke 20. The gap S may be filled with an insulating resin or the like.

According to the above configuration, the inductor body 1
Since the yoke 20 is coupled to the zero core 11, the inductor action in the inductor body 10 is further enhanced by the yoke 20.

That is, in the chip inductor 1 according to the present invention, as described above, the conductor pattern 13 is
Is formed in such a manner that the entire circumference of the coil is wound like a coil, thereby making it possible to reduce the size of the conventional chip inductor and to set the overall length of the conductor pattern 13 to be long. By coupling the inductors 20 and enhancing the inductor action of the inductor body 10, it is possible to obtain a desired high inductance while achieving the smallest possible appearance.

In the chip inductor 1 'shown in FIG. 7, the yoke 20' has two ends 11e, 11e on two sides of the core 11.
Edge portions 20A ', 20A' facing each other and 2 of core 11
The edge 20 extends along the sides 11s, 11s of the side.
A ', 20A', side edges 20B ', 20
B '.

It should be noted that the above-described chip inductor 1 ′
Except for the configuration of the yoke 20 ′, it is basically the same as the above-described chip inductor 1, and there is no difference in operation and effect from the chip inductor 1. 7 are given the same reference numerals in FIG. 7 as those in FIG.

A chip inductor 101 shown in FIG. 8 includes an inductor body 110 and a yoke 120.
The conductor pattern 113 of the inductor body 110 has terminal pad portions 113P formed at both ends thereof, and a plurality of terminal pad portions 113P are provided in the middle.
are formed.

The configuration of the above-described chip inductor 101 is basically the same as that of the above-described chip inductor 1 except that a plurality of terminal pad portions 113p are formed in the middle of the conductor pattern 113. The method of manufacturing the main body 110 is basically the same as the method of manufacturing the inductor main body 10 shown in FIG. 4. Therefore, in the components of the chip inductor 101, those having the same operation as the chip inductor 1 include: In FIG. 4, the same reference numerals as those in FIG.

According to the chip inductor 101 having the above configuration, similarly to the above-described chip inductor 1, it is possible to obtain a desired high inductance while achieving as small a size as possible.

Further, the chip inductor 10 having the above configuration
According to No. 1, by forming a plurality of terminal pad portions 113p, 113p... In the middle of the conductor pattern 113, the terminal pad portion 113p connected to the terminal can be selected according to the position of the terminal on the mounting board. Accordingly, the substantial length of the conductor pattern 113, that is, the value of the inductance can be changed.
1 has a very wide versatility.

In the above-described embodiment, the inductor body and the yoke are connected by caulking. However, the inductor body and the yoke are connected to each other by using an appropriate means other than caulking such as soldering or welding. It is needless to say that can be combined.

In each of the above-described embodiments, a core and a yoke are provided separately from each other, and the yoke is integrally connected to an inductor body having a conductive pattern formed on the core. However, for example, a chip inductor according to the present invention can be manufactured by integrally forming a core and a yoke from a single electromagnetic steel sheet and forming a conductor pattern on the core portion.

[0032]

As described above in detail, the chip inductor according to the present invention has a rectangular plate-shaped core made of a magnetic material.
An inductor body formed by winding a conductor pattern like a coil over an upper surface and a lower surface of the core with an insulating layer interposed therebetween, and at least three cores constituting the inductor body;
And a yoke surrounding the side and coupled to two opposing sides of the core.

According to the above configuration, since the conductor pattern in the inductor body is formed in such a manner that the entire circumference of the core is wound like a coil, the conductor pattern is smaller than a conventional chip inductor in which a winding is wound around a core. As a result, the overall length of the conductor pattern can be set longer than that of a conventional chip inductor having a conductor pattern formed on one surface of the core.

According to the above configuration, since the yoke is connected to the core of the inductor body, the inductor action in the inductor body is further enhanced by the yoke.

Therefore, according to the chip inductor of the present invention, it is possible to obtain a desired high inductance while achieving the smallest possible appearance.

[Brief description of the drawings]

FIGS. 1A, 1B and 1C are an overall plan view and an overall side view showing an embodiment of a chip inductor according to the present invention;
And overall bottom view.

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

FIGS. 3 (a), (b) and (c) are a plan view, a side sectional view, and an end sectional view conceptually showing an inductor main body in the chip inductor shown in FIG. 1;

4 (a) to 4 (f) are conceptual diagrams showing a manufacturing process of an inductor body in the chip inductor shown in FIG.

5 (a) to 5 (d) are views showing a coupling mode between an inductor body and a yoke in the chip inductor shown in FIG. 1;

FIGS. 6 (a) to 6 (d) are views showing a coupling mode between an inductor body and a yoke of a chip inductor according to the present invention.

FIG. 7 is an overall bottom view showing another embodiment of the chip inductor according to the present invention.

FIGS. 8 (a), (b) and (c) are an overall plan view, an overall side view, and an overall bottom view showing another embodiment of the chip inductor according to the present invention.

FIGS. 9A and 9B are external perspective views showing a conventional chip inductor.

[Explanation of symbols]

 1, 1 ': chip inductor, 10: inductor body, 11: core, 11u: upper surface, 11l: lower surface, 12: insulating layer, 13: conductor pattern, 20, 20': yoke, 101: chip inductor, 110: inductor Main body, 111: core, 112: insulating layer, 113: conductor pattern, 113p: terminal pad part, 120: yoke.

Claims (2)

[Claims] 1. An inductor body formed by winding a conductor pattern like a coil on a rectangular plate-shaped core made of a magnetic material over an upper surface and a lower surface of the core with an insulating layer interposed therebetween. And a yoke surrounding three sides and coupled to two opposite sides of the core. 2. The chip inductor according to claim 1, wherein a terminal pad portion is formed in the middle of said conductor pattern.