JPS6226565B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for manufacturing a small-sized, large-capacity ceramic capacitor, particularly a ceramic capacitor suitable for application to grain-boundary insulated semiconductor ceramics.

(Prior Art) FIGS. 1 to 3 are suitable for explaining a conventional example of the present invention.

In other words, the capacitor shown in FIG. 1 is a flat hollow capacitor, and the flat hollow main body 1 is made of grain boundary insulated semiconductor ceramic, such as barium titanate semiconductor ceramic or strontium titanate semiconductor ceramic. grain boundaries
It is made into an insulator using metal oxides such as Bi, Pb, Cu, and Mn. Electrodes 2 and 3 are formed on the inner and outer surfaces of the main body 1, respectively, and lead wires 4 and 5 are connected and fixed with solder.The one shown in Fig. 2 is shown in Fig. 1. Two capacitors are stacked on top of each other and connected in parallel to each other with lead wires 6. Identical parts are given the same numbers, and other detailed explanations will be omitted.

Furthermore, in the one shown in FIG. 3, the grain boundary insulated semiconductor ceramic 7 has a corrugated shape, and electrodes 8 and 9 are provided on both main surfaces.
was formed.

(Problems with the prior art) The capacitances shown in FIGS. 1 to 3 described above all increase the capacitance by 2 to 4 times or more compared to a flat grain-boundary insulated semiconductor ceramic capacitor. However, the capacitance of the capacitance shown in Figure 1 only doubles, and the capacitance of the capacitance of the capacitance shown in Figure 2 can be increased several times by increasing the number of stacks. However, in order to achieve a large capacitance, it is necessary to connect each ceramic capacitor in parallel, and this connection is difficult due to structural constraints, making it unsuitable for practical use.

Furthermore, in the case of the one shown in FIG. 3, there is a phenomenon in which the molded product is deformed during the firing stage, and it is actually difficult to manufacture.

Although the above explanation has been made regarding a grain boundary insulated semiconductor ceramic capacitor, it goes without saying that it also applies to ordinary ceramic capacitors.

(Object of the Invention) Therefore, it is an object of the present invention to provide a ceramic capacitor that does not suffer from the above-mentioned problems.

In other words, the present invention provides a method for manufacturing a small-sized, large-capacity ceramic capacitor.

(Example) The present invention will be described below based on an illustrated example.

First, as shown in FIG. 4, a dielectric ceramic block 11 is prepared. This dielectric ceramic block 11 has outer surfaces facing each other, and has a concrete shape such as a cube or a rectangular parallelepiped. A through hole 12 is formed in the dielectric ceramic block 11. The through hole 12 has wide inner surfaces 13a and 13b facing each other and narrow inner surfaces 14a and 14b facing each other, and has a hollow rectangular cross-sectional shape, for example. Also, the through hole 12
The through holes 12 that are adjacent to each other and the wide inner surface 13
The inner surfaces 14a and 14b are formed in such a way that most of the inner surfaces 14a and 13b overlap each other, and the narrow inner surfaces 14a and 14b are alternately shifted so that they do not overlap each other. One end of the inner surfaces 14a, 14b is the outer surface 11a, 11 of the dielectric ceramic block 11.
They are formed at positions alternately biased towards b.

Dielectric ceramic block 1 with such structure
As a first preferred manufacturing method, the through holes 12 may be included during extrusion molding. Thereafter, the dielectric ceramic block 11 is obtained by firing the compact. As another example,
Pre-fired dielectric ceramic block 1
The through hole 12 may be formed in the hole 1.

Further, when configuring the dielectric ceramic block 11 to be a grain boundary insulated ceramic block, for example, Bi, Pb, Cu, etc., which insulates the grain boundaries of a porcelain semiconductor ceramic block, can be used. , Mn, or other metals or metal oxides are applied by coating, dipping, vacuum deposition, or the like, and then heat-treated in air. As a result, the crystal grain boundaries of the semiconductor ceramic block are made into insulators, and a dielectric ceramic block can be constructed. Incidentally, such a step of forming grain boundaries into an edge body may be performed before or after the step of forming through holes in the semiconductor ceramic block. If possible, if the insulating treatment is performed after forming the through holes, the insulating treatment can be performed reliably to the inside of the dielectric ceramic block. Further, after forming a zigzag dielectric ceramic block to be described later, an insulating treatment may be performed.

Next, as shown in FIG. 5, the narrow inner surfaces 14a and 14b of each through hole 11, which is biased toward the end surfaces 11a and 11b of the dielectric ceramic block 11, are
In the illustrated example, the dielectric ceramic block 11 is cut away from its end faces 11a and 11b by polishing or the like up to the points indicated by dashed-dotted lines A and B. As a result, the dielectric ceramic block 11 has a zigzag shape.

Further, counter electrodes 15, 16 are provided on the inner surface 12a of the groove-shaped portion corresponding to the through hole 12, that is, the zigzag portion, and on the side surfaces 11c and 11d that appear by cutting out the dielectric ceramic block 11.
Further, lead wires 17 and 18 were connected to the opposing electrodes 15 and 16 by solder to produce a ceramic capacitor as shown in FIG.

At this time, the means for forming the electrode is not limited, but
For electrodes formed by methods such as electroless plating, vacuum evaporation, ion plating, and sputtering, a conductive film is formed in unnecessary locations, so it is not recommended to remove the conductive film in those areas. Of course.

Further, in the case of a silver baked electrode, it can be formed by applying a silver paste to the electrode forming area and baking it.

In addition to the above-mentioned order, the order of forming the electrodes is as follows:
The electrodes may be formed in the state shown in the figure, that is, after the through holes 12 are formed. At this time, as shown in FIG. 5, when the portions indicated by dashed-dotted lines A and B are cut out, electrodes are subsequently formed on the side surfaces 11c and 11d that appear after the cutting, if necessary.

Note that the electrode may be formed at least only on the inner surface 12a of the zigzag portion. At this time, a conductive adhesive (not shown) is applied over a wide area to the side surfaces 11c and 11d that are exposed by cutting out the dielectric ceramic block 11, so as to come into contact with the inner surface 12a of the zigzag portion. Then, the lead wire may be connected by soldering at that location.

Furthermore, FIG. 7 shows another embodiment of the present invention. In what is shown in the figure, the dielectric ceramic block 11 has several sets of a plurality of through holes 12;
This group consists of group H. And a dashed line C,
Along D, E, F, that is, adjacent through holes 1
2 alternately displaced narrow inner side 14
Parts a and 14b are cut out to produce a zigzag dielectric ceramic block in the same manner as in the above embodiment. Since the subsequent processing is the same as in the embodiment described above, detailed explanation will be omitted.

8 to 10 show other structural examples of ceramic capacitors obtained by the method of this invention. In FIG. 8, conductive terminals 19 and 20 are connected to make electrical contact with opposing electrodes 15 and 16 of a ceramic capacitor. Further, 21 is an insulating material filled in the groove corresponding to the through hole 12, and improves the strength of the ceramic capacitor when, for example, the conductive terminals 19 and 20 are connected by caulking or the like.

FIG. 9 shows a ceramic capacitor housed in a case 22 and further sealed with a filler 23 to improve mechanical strength, moisture resistance, etc.

Furthermore, in place of the conductive terminals 19 and 20 shown in FIG. 8, FIG. 10 shows conductive terminals 24 and 25 having comb-like protruding terminals 26 and 27 that are inserted into the grooves corresponding to the through holes. Electrodes 15, 16
It is connected and fixed to a ceramic capacitor by making electrical contact with the capacitor.

(Effects) As is clear from the above embodiments, according to the present invention, a zigzag-shaped dielectric ceramic block is formed by forming a through hole in a dielectric ceramic block and cutting out a part of the through hole. The process involves creating a through hole in a predetermined shape and position, and cutting out a dielectric ceramic block at a predetermined position during the molding stage or processing after firing. Therefore, it is possible to manufacture a ceramic capacitor with a large capacity, and the effect is that the capacity can be several times larger than that of the conventional method. It is particularly suitable for application to grain-boundary insulated semiconductor ceramic capacitors that provide a large capacity.

[Brief explanation of the drawing]

Figures 1 to 3 show ceramic capacitors as conventional examples of the present invention. Figure 1 is a perspective view of a flat hollow capacitor, and Figure 2 is a perspective view of two flat hollow capacitors stacked together. Perspective view, Figure 3 is a perspective view of a wavy capacitor, Figures 4 to 6
The figures are perspective views of each step of carrying out the manufacturing method according to the present invention, FIG. 7 is a perspective view of a dielectric ceramic block of another embodiment of the present invention, and FIG.
Figures 1 to 10 are partial cross-sectional views showing other structural examples of ceramic capacitors obtained by the method of the present invention. 11 is a dielectric ceramic block; 12 is a dielectric ceramic block;
The through hole 12a is the side surface of the zigzag portion, 13
a, 13b are wide inner surfaces facing each other, 1
4a and 14b are narrow inner surfaces facing each other;
15 and 16 are electrodes, and 17 and 18 are lead wires.

Claims (1)

[Claims] 1. A step of preparing a cubic or rectangular parallelepiped dielectric ceramic block 11 having outer surfaces facing each other, and having wide inner surfaces 13a, 13b facing each other and narrow inner surfaces 14a, 14b facing each other. The through holes 12 are formed in the dielectric ceramic block 11 so that the wide inner surfaces 13a and 13b of adjacent through holes 12 mostly overlap and the narrow inner surfaces 14a and 14b are alternately displaced. The dielectric ceramic block 11 is cut out including a part of the narrow inner surfaces 14a and 14b of the through holes 12 that do not overlap with adjacent through holes 12, and the dielectric ceramic block 11 is shaped into a zigzag shape. 1. A method for manufacturing a ceramic capacitor comprising the steps of: forming counter electrodes 15 and 16 on at least the side surface 12a of the zigzag portion of the dielectric ceramic block 11 having a zigzag shape. 2. The method of manufacturing a ceramic capacitor according to claim 1, wherein the dielectric ceramic block 11 is made of grain boundary insulated semiconductor ceramic. 3. The wide inner surfaces 13a, 1 facing each other
3b and narrow inner surfaces 14a, 14 facing each other.
2. The method of manufacturing a ceramic capacitor according to claim 1, wherein the through hole 12 having the shape b has a hollow rectangular cross-sectional shape.