JPH0888120A - Laminated coil - Google Patents

Abstract

PURPOSE: To avoid the conversion of Ag forming a conductor pattern as well as the decline in the interlayer resistance by a method wherein a non moisture permeable material is interposed between a conductor pattern forming a coil and a magnetic body layer. CONSTITUTION: In order to manufacture a laminated coil 10, conductor patterns comprising a coil 10A are successively formed by printing process so as to form the coil 10A by repeating the forming step of glass ceramics 10C layers between the conductor pattern of the coil 10A and a high magnetic permeable ferrite 10B. Next, after baking the coil 10A, outer electrodes 15 are formed to manufacture the laminated coil 10. Through these procedures, the water content permeating a magnetic body layer does not reach a coil conductor pattern even if it is exposed in a high moisture environment so that the conversion of Ag forming the conductor pattern as well as the decline in the interlayer resistance may be avoided,thereby enabling the manufacturing steps to be simplified.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminated coil having excellent moisture resistance.

[0002]

2. Description of the Related Art Conventionally, when manufacturing a laminated coil 1 as shown in FIG. 2, a conductive paste and a high-permeability ferrite 2 paste are sequentially formed so that the coil 3 is formed on a high-permeability ferrite base. Printed to form a laminated body,
After firing the laminated body, the external electrodes 4 are formed to complete the laminated coil 1.

There is a sheet laminating method as another manufacturing method different from this, and when manufacturing a laminated transformer 5 in which laminated coils as shown in FIG. 3 are combined, a ferrite green sheet made of a high magnetic permeability ferrite 6 is used. After forming a through hole for interlayer connection on the substrate, a conductor material paste such as Ag is printed to form a conductor pattern that constitutes the primary coil 7 and the secondary coil 8. A plurality of these sheets are laminated and wound. Forming a coil. After forming such a laminated body and firing the body, the external electrodes 9 are formed to complete the laminated transformer 5.

[0004]

However, in the above-mentioned conventional laminated coil, since many small cavities are formed in the ferrite after firing in the reliability test, when exposed to the high temperature and high humidity environment in the reliability test, the water content reaches the inside. There is a problem in that it penetrates and causes migration of Ag in the coil portion, a decrease in interlayer resistance, etc., and sufficient reliability cannot be ensured.

In view of the above problems, it is an object of the present invention to provide a laminated coil which can obtain sufficient reliability even in a high humidity environment.

[0006]

In order to achieve the above-mentioned object, the present invention provides a laminated coil comprising a conductor pattern for forming a coil and a plurality of magnetic layers, wherein the coil is formed. A laminated coil in which a non-moisture permeable material is interposed between the conductor pattern and the magnetic layer is proposed. In claim 2, in the laminated coil according to claim 1, the non-moisture permeable material is glass ceramics. We propose a laminated coil.

[0007]

According to the first aspect of the present invention, the moisture impermeable material is interposed between the conductor pattern forming the coil and the magnetic layer. As a result, even when exposed to a high humidity resistant environment, moisture that has penetrated into the magnetic layer does not reach the coil conductor pattern, and migration of Ag forming the conductor pattern,
Also, the interlayer resistance is not reduced.

Further, according to the second aspect, since the non-moisture permeable material is made of glass ceramics, it can be easily laminated or printed with a ferrite green sheet or the like for forming the magnetic layer during manufacturing. You can do it.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. 1 is a sectional view showing a laminated coil of a first embodiment of the present invention, and FIG. 4 is a manufacturing process drawing.

In this laminated coil 10, as shown in FIG. 1, a glass ceramics 10C is interposed between a conductor pattern forming the coil 10A and a high magnetic permeability ferrite 10B.

In the production of the laminated coil 10 of this embodiment, the conductor patterns forming the coil 10A are sequentially formed by the printing method, and the glass ceramics 10C is provided between the conductor pattern of the coil 10A and the high magnetic permeability ferrite 10B. A layer is formed.

That is, as shown in FIG. 4, in order to construct a coil (A), the glass ceramic paste 12 is printed with a width of 300 μm wider than the coil conductor pattern (B) on the high magnetic permeability ferrite base 11 (B). The conductor pattern 13 is printed with Ag paste (C), and the high-permeability ferrite paste 14 is printed on the connection portion 13a of the conductor pattern 13 on the side where the conductor pattern 13 is printed (D). Next, on the conductor pattern 13 excluding the connecting portion 13b of the conductor pattern 13, 30
The glass-ceramic paste 12 is printed by expanding the width of 0 μm (E). Then, the conductor pattern 13 is formed on the glass ceramic paste 12 so as to be electrically connected to the connecting portion 13b.
(F), the high magnetic permeability ferrite paste 14 is printed again on the high magnetic permeability ferrite paste 14 (G). Further, the glass-ceramic paste 12 is printed on the conductor pattern 13 excluding the connecting portion 13b of the conductor pattern 13 (H). Thereafter, this is repeated a plurality of times to form the coil 10A (B) to (V).

Finally, the high magnetic permeability ferrite paste 14 is printed on the entire surface (W). After this, bake it,
The external electrode 15 is formed to complete the laminated coil 10.

The laminated coil 1 thus formed
0 was left in a constant temperature bath at a temperature of 60 ° C. and a humidity of 95% for 500 hours, and the change in the inductance was examined. As a result, the laminated coil having the conventional structure showed a change in the inductance of −20%. In the laminated coil No. 3, only the inductance change of -1% occurred.

Next, a second embodiment of the present invention will be described.
5 and 6 are a sectional view and an exploded perspective view showing a laminated transformer of a second embodiment to which the present invention is applied. In this example, a laminated transformer was produced by the sheet laminating method.

In the laminated transformer 20 of the second embodiment, 1
Between the secondary coil 20A and the secondary coil 20B and the high magnetic permeability ferrite 20C, the primary and secondary coils 20A and 20
Glass ceramics 20D is interposed so as to surround the conductor pattern forming B.

In the production of the above-mentioned laminated transformer 20, first, a glass ceramic sheet 21 having a hole 21a at a distance of 500 μm from the coil center, for example, a coil conductor pattern (hereinafter referred to as a coil pattern).
A coil pattern 22 forming the primary coil 20A and the secondary coil 20B is formed of Ag, and a glass ceramic sheet 21 on which the coil pattern 22 is formed,
As shown in FIG. 6, the glass ceramic sheet 23 on which the coil pattern of the same shape is not formed is used as the primary coil 2
0A and the secondary coil 20B are laminated in a predetermined order so that the glass ceramic sheet 23 is sandwiched between them, and the hole 21a at the center is filled with the high magnetic permeability ferrite 24. Magnetic susceptibility ferrite sheet 2
5 is laminated and the whole is crimped. After this is fired, the external electrode 26 is formed to complete the laminated transformer 20.

The laminated transformer 20 of the second embodiment is similar to the laminated coil 10 of the first embodiment described above between the conductor patterns of the primary and secondary coils 20A and 20B and the high magnetic permeability ferrite 20C. Since the glass ceramics 20D is interposed in the above, the moisture resistance is excellent as compared with the laminated transformer of the conventional example, and the insulation deterioration between the primary coil 20A and the secondary coil 20B due to humidity is also greatly improved.

The primary coil 20A and the secondary coil 20B
It goes without saying that the same effect can be obtained even if the winding method is a bi-fara winding method.

[0020]

As described above, according to the first aspect of the present invention, since the moisture impermeable material is interposed between the conductor pattern forming the coil and the magnetic layer, it is exposed to a high humidity resistant environment. However, since the moisture that has penetrated into the magnetic layer does not reach the coil conductor pattern, it does not cause migration of Ag forming the conductor pattern, lowering of interlayer resistance, etc., and even in a high humidity environment. It is possible to secure high reliability.

According to the second aspect, in addition to the above effects, since the non-moisture permeable material is made of glass ceramics, at the time of manufacturing, it is laminated with a ferrite green sheet or the like forming the magnetic layer, or Since printing can be easily performed, the manufacturing process can be simplified.

[Brief description of drawings]

FIG. 1 is a sectional view showing a laminated coil according to a first embodiment of the present invention.

FIG. 2 is a sectional view showing a conventional example.

FIG. 3 is a sectional view showing a conventional example.

FIG. 4 is a diagram showing a manufacturing process in the first embodiment of the present invention.

FIG. 5 is a sectional view showing a laminated transformer of a second embodiment of the present invention.

FIG. 6 is an exploded perspective view showing a laminated transformer according to a second embodiment of the present invention.

[Explanation of symbols]

10 ... Laminated coil, 10A ... Coil, 10B ... High permeability ferrite, 10C ... Glass ceramics, 11 ... High permeability ferrite base, 12 ... Ceramic paste, 1
3 ... Conductor pattern, 14 ... High permeability ferrite paste, 15 ... External electrode, 20 ... Multilayer transformer, 20A ... 1
Secondary coil, 20B ... Secondary coil, 20C ... High permeability ferrite, 20D ... Glass ceramics, 21 ... Glass ceramic sheet, 22 ... Coil pattern, 23 ... Glass ceramic sheet, 24 ... High permeability ferrite, 2
5 ... High-permeability ferrite sheet, 26 ... External electrode.

Claims (2)

[Claims] 1. A laminated coil formed by laminating a conductor pattern forming a coil and a plurality of magnetic layers, wherein a moisture impermeable material is interposed between the conductor pattern forming the coil and the magnetic layer. A laminated coil characterized in that 2. The laminated coil according to claim 1, wherein the moisture impermeable material is glass ceramics.