JPH07297072A - Multilayered ceramic capacitor - Google Patents

Abstract

PURPOSE:To provide a small multilayer ceramic capacitor by restraining the rise of surface temperature caused by internal heat. CONSTITUTION:All of the inner electrodes or a part of them are constituted as multilayers 2A, 2B, 3A, 3B, 4A, 4B. Thereby the heat inside a capacitor is effectively dissipated, and the surface temperature rise can be restrained, so that a small multilayered ceramic capacitor can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a monolithic ceramic capacitor having a plurality of internal electrodes to suppress temperature rise.

[0002]

2. Description of the Related Art In recent years, switching power supplies have been widely used with the miniaturization of equipment, and capacitors used therein are required to have low heat generation characteristics.

A conventional monolithic ceramic capacitor will be described below. FIG. 4 shows the structure of a conventional monolithic ceramic capacitor. As shown in FIG. 4, an internal electrode 2A is formed by a screen printing method or the like by using a paste such as Pd on the protective layer 1A obtained by pressure-bonding a plurality of dielectric sheets produced by a doctor blade method or the like, and then,
A protective layer in which a plurality of dielectric sheets are pressure-bonded, a dielectric layer 6A forming a capacitance is pressure-bonded, an internal electrode 3A is formed thereon, and further a dielectric layer 6B forming a capacitance and an internal electrode 4A are formed. 1B is crimped.

The operation of the monolithic ceramic capacitor constructed as described above will be described below. Most of the heat generated inside the monolithic ceramic capacitor is dissipated to the protective layers 1A and 1B via the internal electrodes 2A, 3A and 4A. Therefore, the surface temperature of the protective layers 1A, 1B depends on the heat dissipation characteristics of the internal electrodes 2A, 3A, 4A.

[0005]

However, in the above conventional structure, since the internal electrodes 2A, 3A, 4A are formed of a single layer, most of the heat generated inside is generated by the internal electrodes 2A, 3A, 4A. There was a problem in that the heat dissipation characteristics were poor when the heat was dissipated via the.

The present invention solves the above-mentioned conventional problems, and an object of the present invention is to provide a monolithic ceramic capacitor in which the heat dissipation characteristics of the internal electrodes are improved and the surface temperature rise is suppressed.

[0007]

To achieve this object, the monolithic ceramic capacitor of the present invention has a structure in which a plurality of internal electrodes are formed in a multilayer structure of two or more layers.

[0008]

With this structure, the surface area of the internal electrodes is increased, the heat radiation characteristics are doubled, and the surface temperature rise of the monolithic ceramic capacitor can be suppressed.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. The same components as those of the conventional example are designated by the same reference numerals and the description thereof will be omitted.

As shown in FIG. 1, one dielectric sheet 5A is pressure-bonded onto the protective layer 1A having the internal electrode 2A formed on the upper surface to form the internal electrode 2B. Next, the dielectric layer 6A is pressure-bonded, the internal electrode 3A is formed on the dielectric layer 6A, and then one dielectric sheet 5B is pressure-bonded. Furthermore, a dielectric layer 6B in which the internal electrodes 3B are formed in the reverse order of the above-mentioned lamination,
One dielectric sheet 5C having the internal electrodes 4A formed thereon and the protective layer 1B having the internal electrodes 4B formed thereon are pressure-bonded.
Note that one dielectric sheet 5A to 5C may be a plurality of sheets, and the protective layers 1A and 1B and the dielectric layers 6A and 6B to which a plurality of dielectric sheets are pressure bonded may be one sheet having the same thickness. In addition, internal electrodes 2A and 2B, 3A and 3B and 4
Although the combination electrodes of A and 4B and two sheets have been described, a plurality of combinations of three or more, or only a part thereof may be a plurality of combinations.

Further, the electrodes 2A and 2B, the electrodes 3A and 3B, and the electrodes 4A and 4B are configured to intersect each other from the left and right, respectively, as shown in FIG.
4A, 4B are divided into left and right to form 2C, 2D, 4C, 4D, and electrodes 7A, 7B are arranged in the center, and as shown in FIG. 3, electrodes 2A, 2B, 4A, 4B are arranged in the center. 8A, 8B, 10A, 10B are arranged, and the electrodes 7A, 7B in FIG. 2 are divided into left and right parts 9A, 9B, 9
It is also possible to adopt a configuration of C and 9D.

The operation of the monolithic ceramic capacitor constructed as described above will be described. The heat generated inside the monolithic ceramic capacitor becomes a multi-layer and the surface area is increased.
4A, 4B, 4C, 4D, 7A, 7B, 8A, 8B, 9
By A, 9B, 9C, 9D, 10A, 10B, the heat dissipation characteristics are improved and the surface temperature rise of the protective layers 1A, 1B is reduced.

The characteristics of the multilayer ceramic capacitor according to this embodiment and the conventional single layer internal electrode are shown in comparison with each other (Table 1).

[0014]

[Table 1]

As is clear from this (Table 1), the multilayer ceramic capacitor according to the present embodiment is provided with an internal electrode spacing of 7
0 μm, multi-layer electrode spacing 10 μm, number of dielectric layers 7, protective layer thickness 250 μm, cutting margin 250 μm, capacitance 10,0
Using a laminated ceramic capacitor of 00pF, tan δ1.0%, applying a sine wave with a frequency of 100 kHz and a voltage of 20 Vrms, measuring the surface temperature with an infrared thermometer, and using the difference from room temperature as the heat generation temperature, it is excellent in heat generation temperature. The effect is obtained.

As described above, according to this embodiment, by combining all or some of the internal electrodes of the monolithic ceramic capacitor, the surface area is increased, the heat dissipation characteristics of the internal electrodes are improved, and the temperature of the protective layer is increased. The rise can be suppressed.

[0017]

As is apparent from the above description of the embodiments, according to the present invention, by combining all or a part of the internal electrodes, the heat dissipation characteristics of the internal electrodes are remarkably improved, and the internal ceramic capacitors are improved. The generated heat is dissipated from the internal electrodes, the temperature rise is suppressed, and a great industrial effect that the shape of the monolithic ceramic capacitor can be made smaller than that of the conventional one is obtained.

[Brief description of drawings]

FIG. 1 is a sectional view of a monolithic ceramic capacitor according to an embodiment of the present invention.

FIG. 2 is a sectional view of another embodiment of the monolithic ceramic capacitor.

FIG. 3 is a sectional view of still another embodiment of the same monolithic ceramic capacitor.

FIG. 4 is a sectional view of a conventional monolithic ceramic capacitor.

[Explanation of symbols]

 2A internal electrode 2B internal electrode

Claims (1)

[Claims] 1. A monolithic ceramic capacitor in which all or a part of internal electrodes are formed into a multilayer.