JP2887913B2 - Chip-shaped solid electrolytic capacitor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chip solid electrolytic capacitor, and more particularly to an external electrode structure having improved volume efficiency.

[0002]

2. Description of the Related Art A conventional chip-type solid electrolytic capacitor has a resin mold type in which external positive and negative leads are attached to both ends of a capacitor element shown in FIG. There is a simple resin exterior type in which an external terminal electrode is formed directly on both ends of the element without using an external positive / negative lead after using a simple resin exterior by a method such as electrostatic coating.

[0003]

As shown in FIG. 4, the conventional resin-molded chip-shaped solid electrolytic capacitor has external and positive leads 22 and 23 connected to the capacitor element 21 so that it is small and thin. Was difficult.

[0004] In addition, in the case of using a molded resin sheath, there is a disadvantage that it is not possible to flexibly cope with a change in shape because an expensive mold is used.

To solve these drawbacks, there is a simple resin-encapsulated chip-shaped solid electrolytic capacitor (for example, Japanese Utility Model Application Laid-Open No. 58-51440). As shown in FIG. 5, the external positive / negative terminals 31, 32 can be formed directly from both ends of the element without using external electrode lead-out leads.
Thinning is possible. However, after a resin coating is applied to the peripheral surface of the element by electrostatic coating or the like, a part of the cathode conductor layer is exposed, or an external positive / negative terminal is formed from three layers of a conductive layer, a plating layer, and a solder layer. However, it was complicated and there was a problem in mass production.

In addition, since the conductive layer is formed by silver paste or the like, the shape of the external positive / negative terminal varies, causing poor connection with the pattern of the circuit board at the time of component mounting, or a tomb in which one side of the capacitor floats. There were also problems such as stones.

An object of the present invention is to eliminate the need for external electrode lead-outs, reduce the size and thickness, and eliminate the need for expensive molding dies, as compared with the conventional resin mold type. An object of the present invention is to provide a chip-type solid electrolytic capacitor that can simplify the process as compared with the above, can improve the dimensional accuracy of the external electrode terminals, and can thereby also improve the tombstone phenomenon at the time of mounting on a printed wiring board.

[0008]

According to the present invention, there is provided a chip-shaped solid electrolytic capacitor comprising an anode oxide film, a solid electrolyte layer, and a cathode conductor on an anode body having an anode lead extending from one end face.
A solid electrolytic capacitor element comprising a body layer sequentially formed, before
Perpendicular to the lead end of the solid electrolytic capacitor element
Through the solid electrolytic capacitor element,
Two opposite insulating resin plates, each of which is an anode lead
Comprises an insulating resin sheet having an electrode terminal for the front and back continuously on the front and back of both ends of the de out direction, the each of the heat-resistant insulating resin
Electrode terminal surface at one end of the plate and the solid electrolytic capacitor
The element's cathode conductor layer surface faces each other, each heat resistant insulation
The electrode terminal surface at the other end of the resin plate and the solid electrolytic capacitor
The anode lead of the sensor element faces
It is characterized by being fixed electrically conductively through the adhesive layer .

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings. FIG. 1 is a sectional view of a chip-shaped solid electrolytic capacitor according to a first embodiment of the present invention.

An anode body 1 made of a valve metal, such as tantalum or aluminum, on which an anode lead 2 is implanted is successively provided with a dielectric film layer, a solid electrolyte layer (not shown), and a cathode conductor layer 3 by known means. Is formed. Next, as shown in FIG. 2, an electrode terminal 5 made of a copper foil and a solder plating layer at both ends.
a, 100 microns thick, 3.2 m long with 5b
The electrode terminals 5a and the cathode conductor layer 3 of the heat-resistant insulating resin plate 4 made of a polyimide resin having a width of 1.6 mm and a width of 1.6 mm are electrically connected to the electrode terminals 5b and the anode leads 2 by a conductive adhesive 6 such as a silver paste. , Mechanically connected. Next, the anode lead 2 protruding from the insulating resin plate 4 is cut to form a chip-shaped solid electrolytic capacitor.

The height and mounting test results of the 16 V, 1 μF chip tantalum capacitor thus formed are shown in the table below. At the same time, a comparison was made between a conventional resin mold type and a simple resin exterior type chip tantalum capacitor in which the capacitor element was formed using the same material and the same method, and the results are shown in Table 1.

[0012]

The thickness indicates an average value of n = 50 pieces, and the mounting failure rate indicates a tombstone failure rate in a mounting test of n = 10,000 pieces.

As is clear from Table 1, the embodiment of the present invention has a small thickness and a defective mounting rate is smaller than that of the simple resin exterior type.

FIG. 3 is a sectional view of a solid electrolytic capacitor in chip form according to another embodiment of the present invention. In this embodiment, as shown, the cathode conductor layer 13, the anode lead 1
The length of the electrode terminal on the side connected to 2 is formed longer than that of the other surface, so that the connection reliability can be improved.

[0016]

As described above, the present invention has the following effects by electrically and mechanically connecting a heat-resistant insulating resin plate having electrode terminals at both ends to a capacitor element. (1) Compared with the conventional resin mold type, external electrode lead-out is not required, so that the size and thickness can be reduced. Further, since an expensive mold is not required, it is possible to flexibly cope with a change in the shape of the capacitor. (2) The process can be simplified as compared with the conventional simple resin exterior type, and the dimensional accuracy of the external electrode terminals is high, so that the tombstone phenomenon that occurs when mounting the printed wiring board can be improved.

[Brief description of the drawings]

FIG. 1 is a sectional view of one embodiment of the present invention.

FIG. 2 is a cross-sectional view of a heat-resistant insulating resin plate having electrode terminals at both ends used in one embodiment of the present invention.

FIG. 3 is a sectional view of another embodiment of the present invention.

FIG. 4 is a sectional view of an example of a conventional resin-molded chip solid electrolytic capacitor.

FIG. 5 is a cross-sectional view of an example of a conventional simple resin-encapsulated chip solid electrolytic capacitor.

[Explanation of symbols]

 Reference Signs List 1 anode body 2, 12 anode lead 3, 13 cathode conductor layer 4 heat-resistant insulating resin plate 5a, 5b electrode terminal 6 conductive adhesive material 21 capacitor element 22 external anode lead 23 external cathode lead 31 anode terminal 32 cathode terminal

Claims (4)

(57) [Claims] An anode body having an anode lead led out from one end surface is provided with an anodic oxide film, a solid electrolyte layer, and a cathode conductor.
A solid electrolytic capacitor element in which layers are sequentially formed, and an anode lead-out end face of the solid electrolytic capacitor element.
Parallel to the intersecting plane, through the solid electrolytic capacitor element
Two insulating resin plates facing each other, each of which is an anode
Comprises an insulating resin sheet having an electrode terminal for the front and back continuously on the front and rear ends of the over-de extending direction, before and one end of the electrode terminal surface of the respective heat-resistant insulating resin sheet
The solid electrolytic capacitor element faces the cathode conductor layer surface
And the electrode terminal table on the other end of each heat-resistant insulating resin plate
The surface and the anode lead of the solid electrolytic capacitor element face each other.
And, electrically conductive to solid via a respective conductive adhesive layer
A chip-shaped solid electrolytic capacitor characterized by being worn . 2. The solid electrolytic capacitor according to claim 1, wherein said heat-resistant insulating resin plate is a polyimide resin. 3. The solid electrolytic capacitor according to claim 1, wherein the electrode terminals formed on the heat-resistant insulating resin plate are composed of two layers, a copper foil and a solder layer. 4. The chip according to claim 1, wherein the side of the electrode terminal formed on the heat-resistant insulating resin plate connected to the anode lead and the cathode conductor layer is formed longer than the other surface. Shaped solid electrolytic capacitor.