JP2707863B2 - 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-shaped solid electrolytic capacitor, and more particularly to an external electrode structure of a chip-shaped solid electrolytic capacitor with improved miniaturization and thinning.

[0002]

2. Description of the Related Art A conventional chip-shaped solid electrolytic capacitor has external anode lead-out leads attached to both ends of a capacitor element shown in FIG. After simple resin coating using a method such as electrostatic coating using resin, external terminal electrodes consisting of a conductor layer, a plating layer, and a solder layer are formed at both ends of the device without using external positive / cathode extraction leads. There is a simple resin exterior type shown in FIG.

[0003]

As shown in FIG. 4, a conventional resin-molded chip-type solid electrolytic capacitor has external and positive leads 22 and 23 connected to a capacitor element 21 so that it can be reduced in size and thickness. It 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. In order to solve these drawbacks, there is a simple resin-encapsulated chip solid electrolytic capacitor (for example, Japanese Utility Model 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 device without using external electrode lead-outs, so that the size and thickness can be reduced compared to the resin mold type. However, after covering the element surface with resin by electrostatic coating etc., a part of the cathode conductor layer is exposed, or external positive / negative terminals are formed from three layers of conductive layer, plating layer and solder layer. However, it was complicated and there was a problem in mass production.

[0005] Further, since the conductive layer is formed by silver paste or the like, the shape of the external positive / negative terminal varies, which causes a connection failure 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.

A first 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 molds, as compared with the conventional resin mold type. An object of the present invention is to provide a chip-shaped solid electrolytic capacitor that can flexibly respond to a shape change.

A second object of the present invention is to simplify the process and improve the dimensional accuracy of the external electrode terminals as compared with the conventional simple resin exterior type, and to reduce the tombstone phenomenon that occurs when mounting a printed wiring board. It is an object of the present invention to provide a chip-shaped solid electrolytic capacitor that can be used.

[0008]

According to the present invention, there is provided a chip-type solid electrolytic capacitor comprising: an anode body having an anode lead; and an anode oxide film layer, a solid electrolyte layer, and a cathode conductor layer sequentially formed on the anode body. And a chip-shaped solid electrolytic capacitor made of a heat-resistant insulating resin plate having electrode terminals at both ends connected to the upper and lower surfaces of the element, wherein the through-holes are formed in the aforementioned electrode terminals. You.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings. FIG. 1 is a longitudinal sectional view of a solid electrolytic capacitor chip according to a first embodiment of the present invention. A dielectric film layer, a solid electrolyte layer (not shown), and a cathode conductor layer 3 are sequentially formed on the anode body 1 made of tantalum metal with the anode lead 2 implanted by known means.

Next, as shown in FIG. 2, the terminal electrodes 5a, 5b
The electrode terminals 5a and the cathode conductor layer 3 of the heat-resistant insulating resin plate 4 having through holes 6a and 6b at substantially the center, and the electrode terminals 5b and the anode leads 2 are electrically connected by a conductive adhesive 7 such as silver paste. , Mechanically connected. The heat-resistant insulating resin plate 4 is made of a polyimide resin and has a thickness of 100 microns.
The length is 3.2 mm, the width is 1.6 mm, and the electrode terminals are formed from copper foil and solder plating. What is the diameter of the through hole?
5 mmφ, a solder plating layer is formed on the inner side, and the upper electrode terminal and the lower electrode terminal formed at both ends of the heat-resistant insulating resin plate 4 are electrically connected by the through holes.

Next, the anode lead 2 protruding from the insulating resin plate 4 is cut to form a chip-shaped solid electrolytic capacitor.

Table 1 shows the height dimensions and mounting test results of the thus formed chip tantalum capacitor of 16V1 μF or less, in comparison with the conventional product.

[0013]

The height dimension indicates an average value of n = 50 pieces, and the mounting failure rate indicates a tombstone failure rate when n = 10,000 pieces.

FIG. 3 is a longitudinal sectional view of a chip-shaped solid electrolytic capacitor according to another embodiment of the present invention.

By increasing the number of through holes and changing the connection with the capacitor element from a conductive adhesive to solder, the connection strength between the electrode terminal and the circuit board and the connection strength between the capacitor element and the electrode terminal are increased. Thus, a chip-shaped capacitor having higher connection reliability can be obtained.

[0017]

As described above, the present invention has the following effects by electrically and mechanically connecting a heat-resistant insulating resin plate having a through hole at the center of an electrode terminal to a capacitor element. (1) Compared with the conventional resin mold type, external electrode lead-outs are not required, so that a compact and thin form can be achieved. or,
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 at the time of mounting the printed wiring board can be improved.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a chip-shaped solid electrolytic capacitor according to one embodiment of the present invention.

FIG. 2 is a longitudinal sectional view of a heat-resistant insulating resin plate used in one embodiment of the present invention.

FIG. 3 is a vertical sectional view of a chip-shaped solid electrolytic capacitor according to another embodiment of the present invention.

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

FIG. 5 is a longitudinal sectional view of a conventional simple resin exterior chip solid electrolytic capacitor.

[Explanation of symbols]

 Reference Signs List 1 anode body 2 anode lead 3 cathode conductor layer 4 heat-resistant insulating resin plate 5a, 5b electrode terminal 6a, 6b, 16a, 16b through hole 7 conductive adhesive 17 solder 21 capacitor element 22 external anode lead 23 external cathode lead 31 Anode terminal 32 Cathode terminal

Claims (2)

(57) [Claims] 1. A solid electrolytic capacitor element in which an anodic oxide film layer, a solid electrolyte layer, and a cathode conductor layer are sequentially formed on an anode body having an anode lead, and connected to the upper and lower surfaces of the solid electrolytic capacitor element. A chip-shaped solid electrolytic capacitor comprising a heat-resistant insulating resin plate having electrode terminals at both ends, wherein the electrode terminals of the heat-resistant insulating resin plate have through holes. 2. The solid electrolytic capacitor according to claim 1, wherein the upper and lower electrode terminals of said heat-resistant insulating resin plate are electrically connected by through holes.