JPH08330137A - Multilayer inductor - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a highly reliable laminated inductor which is small in size, has a high inductance value even if the volume is small. [Structure] The windings of the laminated inductor are formed by alternately forming a winding pattern made of conductors 2a having different inner diameters and not overlapping with each other, and a ceramic portion 1a, thereby ensuring a distance (insulation) between the conductors. A high number of conductor turns can be obtained while suppressing an increase in magnetic path length.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminated inductor used as an electronic component.

[0002]

2. Description of the Related Art In recent years, due to the miniaturization of electronic equipment, miniaturization of an inductance element with the same characteristics is required. In order to miniaturize the inductance element,
In the design of the laminated inductance element, the inductance value decreases due to the decrease in the magnetic path cross-sectional area, so it is necessary to compensate for the decrease by increasing the number of turns.

Generally, in a laminated inductor, windings having the same inner diameter are laminated and formed, and the conductors are arranged in a line in the laminating direction.

In such an inductor, the inductance of the element is adjusted by the magnetic permeability of the ceramics and the number of windings, that is, the number of laminated layers of the conductor and the ceramics. In particular, the inductance of the element is finely adjusted by the number of windings. It has been decided.

The number of turns, that is, the number of layers, may range from 10 to 50 turns in a high inductance element.

[0006]

However, in the conventional laminated inductor, if the number of layers is increased and the number of turns is increased, insulation between conductors is ensured and line capacitance is reduced.
Layer thickness per turn of conductor winding (distance between conductors is about 15
.mu.m or more) cannot be changed, so that there is a problem that the magnetic path length increases as the number of turns increases, and a high inductance value cannot be easily obtained.

Further, in order to obtain a high inductance value, an extremely high number of layers is required, which causes a problem that the cost of the element becomes extremely high.

An object of the present invention is to provide a highly reliable laminated inductor which can obtain a high inductance value even if it is small and has a small volume.

[0009]

According to the present invention, the conductor windings having different inner diameters and having non-overlapping winding patterns are alternately formed to secure a distance (insulating property) between the conductors. Obtaining a high number of conductor turns while suppressing the increase in path length,
It is intended to obtain a small-sized laminated inductor element having a high inductance value.

That is, according to the present invention, insulating ceramic powder and silver or conductive powder are made into a paste, which is laminated by a printing method to form a laminated winding of a conductor.
In a multilayer inductor that was fired at the same time, sandwiching the insulating ceramic layer, excluding the joint between the patterns,
The laminated inductor is characterized in that winding patterns that do not overlap each other are alternately formed and laminated and fired.

[0011]

[Function] The windings of the laminated inductor are alternately formed with winding patterns having different inner diameters and not overlapping to secure a distance (insulation) between conductors and suppress an increase in magnetic path length. It is possible to obtain a high number of turns of the conductor. As a result, a multilayer inductor element having a small size and a high inductance value can be obtained.

[0012]

EXAMPLES Regarding the laminated inductor of the example of the present invention,
This will be described with reference to the drawings.

Ferrite powder was prepared as the ceramic powder. The average particle size of the powder is about 1 μm. This powder was mixed with a binder and a solvent in the ratios shown in Table 1, and the mixture was kneaded with a three-roll mill to prepare a magnetic portion paste.

[0014]

The powder for the conductor layer has an average particle size of 0.5 μm.
m Ag powder was prepared. This powder was mixed with a binder and a solvent in the ratios shown in Table 2, and the mixture was kneaded with a three-roll mill to prepare a conductor layer paste.

[0016]

Next, the produced magnetic portion paste was laminated by a printing method to a predetermined thickness (0.5 mm).

On top of that, the conductor 2 of the pattern of FIG.
a (about 10 μm thick) was formed, and further, a magnetic portion was formed with a thickness of 10 μm in the pattern of FIG. Next, FIG.
(C) Form the conductor 2a (about 10 μm thick) of the pattern,
Further, the ceramic portion 1a is formed into a pattern with the pattern of FIG.
It was formed with a thickness of 0 μm. Next, the conductor 2a having the pattern shown in FIG. 1 (e) was formed, and further, the ceramic portion 1a was formed to have a thickness of 10 μm in the pattern shown in FIG. 1 (b).

In this manner, the pattern shown in FIG. 1 (c) -FIG.
(D) -FIG. 1 (e) -FIG. 1 (b) was repeatedly laminated to form a laminated winding.

The distance between the overlapping conductors (same pattern) is 20 μm.

As a final conductor, a conductor having the pattern shown in FIG. 1F is formed after the pattern shown in FIG. 1D, and a ceramic portion is formed on the conductor with a predetermined thickness (0.
5 mm).

At this time, the number of turns of the laminated winding was changed from 10 to 50.

The above-prepared laminated body is made to have a predetermined size (2 m
m × 1.5 mm).

FIG. 2 shows a cross-sectional view of the above-mentioned laminated element as the structure of the laminated body. Reference numeral 1 is a ceramic layer, and 2 is a laminated inductor including a conductor winding portion.

After the above laminated and cut laminated body was debindered, it was co-fired at 900 ° C.

Although firing was performed at 900 ° C. in the examples,
The firing temperature may be in the range of approximately 850 ° C to 900 ° C.

On the surface of the fired laminated body where the leads of the laminated winding of the conductor are exposed, a conductive paste containing Ag as a main component is applied and baked at about 300 ° C. to form an external electrode. Formed.

The relationship between the frequency and the inductance of the laminated inductor manufactured as described above was evaluated using an impedance analyzer HP4191A manufactured by YHP.

(Comparative Example) The same method as in the example was prepared until the powder was made into a paste. The produced magnetic portion paste was laminated by a printing method to a predetermined thickness (0.5 mm).

On top of that, the conductor 2 of the pattern of FIG.
a (about 10 μm thick) was formed, and further, the ceramic portion 1a was formed with a thickness of 10 μm in the pattern of FIG. 3 (b). Next, a conductor 2a having a pattern of FIG. 3C (thickness of about 10 μm) was formed, and further, a ceramic portion 1a having a thickness of 10 μm was formed by the pattern of FIG. 3D. Next, the conductor 2a having the pattern of FIG. 3 (e) was formed, and further, the ceramic portion 1a was formed to have a thickness of 10 μm in the pattern of FIG. 3 (b).

In this way, the pattern of FIG. 3 (c) -FIG.
(D) -FIG. 3 (e) -FIG. 3 (b) was repeatedly laminated to form a laminated winding.

The distance between the conductors is the same as that of the embodiment and is 20 μm.
m.

As a final conductor, a conductor of the pattern shown in FIG. 3 (f) is formed after the pattern of FIG. 3 (b), and a ceramic portion is formed on the conductor with a predetermined thickness (0.
5 mm).

At this time, the number of turns of the laminated winding was changed from 10 to 50.

In this case, the laminated winding is formed with 1/2 turn pitch, but it is the same even if the inner diameter of the laminated winding is constant even in the laminating method with other pitches such as 3/4 turn pitch.

Similar to the example, the laminated body prepared above was cut into a predetermined size (2 mm × 1.5 mm).

FIG. 4 shows a cross-sectional view of the above-described laminated element as the structure of the laminated body. Reference numeral 1 is a ceramic portion, 2 is a conductor, and is a laminated inductor including a ceramic layer and a conductor winding portion.

The relationship between the frequency and the inductance of the manufactured laminated inductor was evaluated using an impedance analyzer HP4191A manufactured by YHP, as in the examples.

FIG. 5 is a diagram showing the relationship between the number of turns and the inductance of the laminated inductors manufactured in the example and the comparative example. A is an example and B is a comparative example. This Figure 5
Therefore, as shown in the embodiment, by forming winding patterns having different inner diameters and not overlapping with each other,
It can be seen that an inductance higher by 50 to 70% can be obtained with the same number of turns as compared with the conventional case where a laminated winding having a pattern with the same inner diameter is formed.

Further, in order to obtain the same inductance, for example, to obtain an inductance of 30 μH, in the comparative example which is the conventional method, the laminated winding has 50 turns, whereas in the embodiment, the winding has 30 turns. It turns out that laminated winding is sufficient. This brings about a dramatic cost reduction in a laminated inductor in which the lamination process occupies most of the manufacturing cost.

In this example, ferrite powder was used as the ceramic powder, but other ceramic powders can be used as long as they can be fired at 900 ° C. or lower.
The same effect can be obtained.

Further, in this embodiment, the pastes were prepared with the compounding ratios shown in Tables 1 and 2, but any component and compounding ratio other than these may be used as long as a printable paste can be obtained.

Further, in this embodiment, the three rolls were used for kneading the blend, but other than this, a homogenizer, a sand mill or the like may be used.

[0045]

As described above, according to the present invention, by forming the laminated winding by alternately laminating the winding patterns which have different inner diameters and do not overlap each other, it is possible to realize the same number of conventional windings. In comparison, a compact, high inductance, and highly reliable multilayer inductor was obtained.

[Brief description of drawings]

FIG. 1 is a plan view showing conductor and ceramic patterns in a lamination process of a laminated inductor according to an embodiment of the present invention.
FIG. 1A is a plan view showing a conductor pattern. FIG. 1B is a plan view showing a ceramic pattern. FIG. 1C is a plan view showing a conductor pattern. FIG. 1D is a plan view showing a ceramic pattern. FIG. 1E is a plan view showing a conductor pattern. FIG. 1F is a plan view showing a conductor pattern.

FIG. 2 is a plan view showing a laminated state of conductors of an inductor cross section laminated in an example of the present invention.

FIG. 3 is a plan view showing patterns of conductors and ceramics in a lamination process of a laminated inductor of a comparative example. FIG.
(A) is a top view which shows a conductor pattern. FIG. 3B is a plan view showing a ceramic pattern. FIG. 3C is a plan view showing a conductor pattern. FIG. 3D is a plan view showing a ceramic pattern. FIG. 3E is a plan view showing a conductor pattern. FIG. 3F is a plan view showing the conductor pattern.

FIG. 4 is a plan view showing a laminated state of conductors of an inductor cross section laminated in a comparative example.

FIG. 5 is a diagram showing the relationship between the number of turns and the inductance of the laminated winding of the example and the comparative example.

[Explanation of symbols]

 1 Ceramics Layer 1a Ceramics Part 2 Conductor Winding Part 2a Conductor A Example B Comparative Example

Claims (1)

[Claims] 1. A laminated inductor in which an insulating ceramic powder and a conductive powder of silver or copper are made into a paste, which is laminated by a printing method to form a laminated winding of a conductor, and which is co-fired to obtain insulation. A laminated inductor characterized by alternately forming winding patterns which do not overlap each other except for a joint portion between the patterns, sandwiching a conductive ceramics layer, and performing laminated firing.