JPH02260405A - Laminated inductor - Google Patents

Abstract

PURPOSE:To prevent a flux density from becoming large in a prescribed position and to obtain a laminated inductor whose magnetic saturation is hardly caused by a method wherein a layer whose permeability is low is formed at the side of a conductor pattern so as to come into contact with the pattern. CONSTITUTION:A conductor pattern 11 of silver is wound spirally inside a magnetic substance layer 10 of a ferrite; a ferrite paste and a conductor paste are printed and laminated alternately. The conductor pattern 11 is wound between magnetic substance layers while its end parts are connected; it is superposed and formed in a laminate direction; the prescribed number of turns are formed according to an inductance value. Layers 12 of a material whose permeability is low are formed so as to come into contact with the conductor pattern at both ends; the layers 12 are formed at the inside of the conductor pattern 11 situated at both ends in the laminate direction. Thereby, it is possible to prevent a magnetic flux to be concentrated in a prescribed position; it is possible to easily prevent magnetic saturation from being generated even in a closed magnetic circuit type.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to the structure of a laminated inductor, and particularly to the structure of a laminated inductor in which magnetic saturation is less likely to occur.

[Prior art]

With the demand for smaller and thinner electronic components, multilayer inductors are also attracting attention in the field of inductance components. In this method, a magnetic material and a conductor are alternately laminated by printing or a sheet method without using a winding wire to form a conductor pattern circulating inside the magnetic material.

FIG. 4 is a front sectional view of such a laminated inductor. Conductor patterns 41 are formed in the magnetic body 40 so as to overlap in the stacking direction. The conductor pattern 41 is surrounded by the magnetic material 40, resulting in a closed magnetic path type inductor.

〔assignment〕

The laminated inductor described above is a closed magnetic circuit type, so
Magnetic saturation occurs, making it difficult to obtain sufficient characteristics with inductance, Q, etc.

When we investigated this magnetic saturation, we found that the magnetic flux density was extremely large near the inner corners of the conductor pattern at the upper and lower ends.

The present invention provides a multilayer inductor that prevents magnetic flux density from increasing at a specific position and is less likely to cause magnetic saturation.

[Means to solve the problem]

The present invention solves the above problems by forming a layer with low magnetic permeability inside the conductor pattern in contact with it.

That is, in a laminated inductor having conductor patterns whose ends are connected between magnetic layers and which overlap and circulate in the lamination direction, the magnetic material is in contact with the conductor patterns at both ends in the lamination direction and is located inside the conductor patterns. It is characterized by comprising a layer of a material having lower magnetic permeability than the body layer.

Furthermore, better characteristics can be obtained by replacing the conductor patterns with a material having low magnetic permeability.

Further, the material with low magnetic permeability may be a non-magnetic material.

[Effect]

The magnetic flux generated around the conductor pattern is concentrated in areas with high magnetic permeability rather than in areas with low magnetic permeability. Since there are portions with low magnetic permeability inside the conductor patterns at both ends, it is possible to prevent magnetic flux from concentrating on the inner corner portions of the conductor patterns at the ends.

This prevents the concentration of magnetic flux in this portion, and the magnetic flux is dispersed in the central portion of the main magnetic path, thereby preventing magnetic saturation of the inductance element.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a front sectional view showing an embodiment of the present invention. Ni
-A silver conductor pattern 11 spirally circulates within a magnetic layer 10 of ferrite such as Zn-based ferrite. This is made by alternately printing and laminating ferrite paste and conductor paste. The conductor pattern is formed by going around between the magnetic layers while connecting the ends thereof, and overlapping in the stacking direction. A predetermined number of turns are formed depending on the inductance value.

In the multilayer inductor of the present invention, Jii1 is made of a material with a low i31 ratio in contact with at least the conductor patterns at both ends.
2 is formed. This layer 12 of a material with low magnetic permeability is formed on the inner part of the conductive pattern 11 located at both ends in the stacking direction.

Although not shown, a layer of a material with low magnetic permeability may be formed in contact with the inside of the conductive pattern and extending in a cylindrical shape between the conductive patterns at both ends.

Note that, as shown in FIG. 2, if the conductive patterns 21 are also replaced with a layer 22 of a material with low magnetic permeability, it becomes difficult for magnetic flux to pass between the conductive patterns 21, so that the inductance can be increased. As the material 22 with low magnetic permeability, a material having the same composition as that of the layer on the end face side may be used.

Further, as shown in FIG. 3, there is a structure in which a layer 32 of a material with low magnetic permeability is formed in a cylindrical shape inside the conductor pattern 31 at the part that contacts the conductor pattern 31 and at the part that crosses the magnetic path inside the conductor pattern 31. You can also use it as

As the material with low magnetic permeability, it is preferable to use a Ni-Zn ferrite with a low Ni content, or a non-magnetic material. Note that it is advantageous to use a material with a low dielectric constant between the conductor patterns because stray capacitance between the patterns can be reduced.

The characteristics of the multilayer inductor according to the present invention having the above structure will be explained.

The dimensions of the laminated inductor are a magnetic path cross-sectional area of 0.744 mm.
”, the electrode width is 0°13 mm, the electrode thickness is 15 μm, and a low magnetic permeability layer is formed inside the conductor pattern with a width of 0.1 mm. The magnetic layer is made of a material with μ = 580 and a low magnetic permeability material. A sample of μ = 100 was obtained for the layer.

Judging from the superimposed DC characteristics, it was confirmed that the magnetic flux density at the inner corners of the conductor pattern at both ends in the stacking direction was small.

Since the inductance value is lower because the material is replaced with a magnetic material with low magnetic permeability, it is necessary to increase the number of turns slightly, but judging from the DC superposition characteristics as mentioned above, the concentration of magnetic flux is greatly alleviated and saturation is achieved. It's getting harder to do.

〔effect〕

According to the present invention, it is possible to prevent magnetic flux from concentrating on a specific position, and it becomes easy to prevent magnetic saturation even in a closed magnetic circuit type laminated inductor.

Thereby, the inductance value, Q value, etc. of the inductor can be improved.

Note that the magnetic flux density between the conductor patterns is also reduced, which is advantageous in terms of improving Q.

[Brief explanation of drawings]

1 to 3 are front sectional views showing embodiments of the present invention, and FIG. 4 is a front sectional view showing an example of a conventional laminated inductor. 10.20.30...Magnetic layer

Claims (7)

[Claims] (1) In a laminated inductor having a conductor pattern whose ends are connected between magnetic layers and which overlap and circulate in the lamination direction, the conductor pattern is in contact with the conductor patterns at both ends in the lamination direction and is located inside the conductor pattern. A multilayer inductor characterized by comprising a layer of a material having lower magnetic permeability than a magnetic layer. (2) In a laminated inductor including a conductor pattern whose ends are connected between magnetic layers and which overlap and circulate in the lamination direction, the space between the conductor patterns is replaced with a material having a lower magnetic permeability than the magnetic material, and the laminated In contact with the conductor pattern at both ends of the direction,
A laminated inductor comprising a layer of a material having a lower magnetic permeability than the magnetic layer located inside the conductor pattern. (3) The laminated inductor according to claim 2, wherein the materials with low magnetic permeability disposed between the conductor patterns and inside the conductor patterns are the same. (4) In a laminated inductor having a conductor pattern whose end portions are connected between magnetic layers and which overlap and circulate in the lamination direction, the laminated inductor is in contact with the inside of the conductor pattern and is connected to each other to form a cylindrical shape. A multilayer inductor comprising a layer made of a material having lower magnetic permeability than the magnetic layer. (5) In a laminated inductor including a conductor pattern whose ends are connected between magnetic layers and which overlap and circulate in the lamination direction, the space between the conductor patterns is replaced with a material having lower magnetic permeability than the magnetic material, and the conductor A laminated inductor comprising layers of a material having a lower magnetic permeability than the magnetic layer, which are connected to each other to form a cylindrical shape while being in contact with the inside of the pattern. (6) In a laminated inductor having conductor patterns whose ends are connected between magnetic layers and which overlap and circulate in the lamination direction, contacting at least the conductor patterns at both ends in the lamination direction,
A multilayer inductor comprising a layer of a non-magnetic material located inside the conductive pattern. (7) In a laminated inductor including a conductor pattern whose ends are connected between magnetic layers and which circulate in a superimposed manner in the lamination direction, the space between the conductor patterns is replaced with a non-magnetic material, and at least both ends in the lamination direction are replaced with a non-magnetic material. A laminated inductor comprising a layer of a non-magnetic material that is in contact with the conductive pattern and located inside the conductive pattern.