JPH05335175A - Laminated ceramic capacitor - Google Patents

Abstract

PURPOSE:To protect a laminate ceramic capacitor from troubles caused by thermal shock at mounting or in use by a method wherein the joint of an inner electrode to an outer electrode is enlarged in thickness. CONSTITUTION:Paste of ceramic ad palladium is printed on a ceramic dielectric 4 formed into a sheet to serve as an inner electrode 1. The part of the inner electrode 1 brought into contact with an outer electrode 3 is enlarged in thickness. Thereafter, the ceramic dielectric sheets 4 where the inner electrode 1 is printed are laminated and sintered, and silver paste is applied onto the side faces of the laminated dielectric sheets and sintered for the formation of the outer electrodes 3. By this setup, a joint area between an inner electrode and an outer electrode is not required to be lessened when a laminated ceramic capacitor is enhanced in capacity lessening inner electrode layers in thickness, so that the laminated ceramic capacitor high in resistance to a thermal shock such as a temperature cycle 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, and more particularly to electrodes of a monolithic ceramic capacitor.

[0002]

2. Description of the Related Art As shown in FIG. 3, a conventional monolithic ceramic capacitor has a structure in which an internal electrode 9 is printed on a ceramic dielectric 12 and laminated, and after firing, an external electrode 11 is formed.

In particular, the internal electrode 9 is formed to have a thickness as uniform as possible, and the connecting portion 10 of the internal electrode 9 with the external electrode 11 also has the same thickness.

Further, particularly recently, with the increase in capacity of monolithic ceramic capacitors, the ceramic dielectric 1
2 and the internal electrodes 9 tend to be thin.

[0005]

In this conventional monolithic ceramic capacitor, such a ceramic dielectric 12 is used.
Also, as the inner electrode 9 becomes thinner, the connecting portion 10 between the inner electrode and the outer electrode also becomes thinner and the connecting area becomes smaller, so that the connection strength between the inner electrode 9 and the outer electrode 11 tends to decrease.

For this reason, there has been a problem that the rate of occurrence of connection failure between the internal electrode 9 and the external electrode 11 due to heat shock during mounting or during use of the capacitor increases.

The present invention has been made in view of the above-mentioned conventional circumstances, and therefore an object of the present invention is to provide a novel monolithic ceramic capacitor capable of solving the above problems inherent in the prior art. Especially.

[0008]

In order to achieve the above object, the multilayer ceramic capacitor according to the present invention is constructed by increasing the thickness of the connection portion of the internal electrodes, particularly the internal electrodes with the external electrodes. The connection strength between the internal electrode and the external electrode is increased.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will now be specifically described with reference to the drawings for each of its preferred embodiments.

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

Referring to FIG. 1, first, a silver-palladium paste as an internal electrode 1 is printed to a thickness of 5 μm as an internal electrode 1 on a ceramic dielectric body 4 containing barium titanate as a main component and processed into a sheet shape having a thickness of about 25 μm. did. At this time, the thickness of the mask at the time of printing was partially increased, and particularly, the portion corresponding to the connection portion 2 of the internal electrode 1 with the external electrode 3 was made to have a thickness of 10 μm. Thereafter, sheet-shaped ceramic dielectrics having the internal electrodes 1 printed thereon were laminated, sintered at about 1200 ° C., coated with silver paste, and baked at about 600 ° C. to form the external electrodes 3.

According to the above method, the length is 3.2 mm and the width is 1.
A laminated ceramic capacitor having a size of 6 mm, a thickness of 1.0 mm, a rated voltage of 16 V and a capacitance of 1 μF was obtained.

A temperature cycle test was carried out on 100 of these monolithic ceramic capacitors and 100 monolithic ceramic capacitors of the same shape, same rating and same capacity formed by the conventional method, and the following remarkable improvement results were obtained. ..

[0014]

[Table 1]

FIG. 2 is a sectional view showing a second embodiment according to the present invention.

Referring to FIG. 2, this second embodiment is
The thickness of the connection portion 6 of the internal electrode 5 with the external electrode 7 is 25 μm.
And the ceramic dielectric 8 have the same thickness as the external electrode 7
The connection with is strengthened.

[0017]

As described above, according to the present invention,
Since the metal paste printed as the internal electrode was formed so that the connection between the internal electrode and the external electrode was thicker than other parts, when the internal electrode was made thinner as the capacity of the multilayer ceramic capacitor increased. Moreover, it is not necessary to reduce the connection area between the internal electrode and the external electrode, and it is possible to obtain a monolithic ceramic capacitor that is resistant to thermal shock such as temperature cycling.

[Brief description of drawings]

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

FIG. 2 is a sectional view showing a second embodiment according to the present invention.

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

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Internal electrode 2 ... Internal electrode (connection part with external electrode) 3 ... External electrode 4 ... Ceramic dielectric 5 ... Internal electrode 6 ... Internal electrode (connection part with external electrode) 7 ... External electrode 8 ... Ceramic dielectric 9 ... Internal electrode 10 ... Internal electrode (connection part with external electrode) 11 ... External electrode 12 ... Ceramic dielectric

Claims (1)

[Claims] 1. A ceramic dielectric processed into a thin sheet is printed with a metal paste as an internal electrode, laminated and baked in a high-temperature firing furnace, and then the metal paste, metal plating, or a combination of both. In a monolithic ceramic capacitor having external electrodes formed, a metal paste printed as an internal electrode is formed so that a connecting portion between the internal electrode and the external electrode is thicker than other portions. Capacitors.