JPH05226193A - Solid-state chip electrolytic capacitor - Google Patents

Abstract

PURPOSE:To form external electrode terminals with excellent size precision and to perform mounting by an automatic mounter and soldering securely. CONSTITUTION:A recession 15 in which a positive drawing-out wire 12 bent is laid is provided on the side of the positive drawing-out wire 12 of sheathing resin 16 which covers the capacitor element 11 so that the positive drawing-out wire 12 may be drawn out on one side. Besides, a positive terminal part 23 is formed by burying in this recession 15 conductive paint 19 to be electrically connected to the positive drawing-out wire 12 and making the positive end surface approximately flat, and a negative terminal part 24 to be electrically connected with the negative layer 13 of the capacitor element 11 is formed on the opposite side to this positive terminal part 23. On this occasion, the surface area of the positive terminal part 23 is made approximately equal to that of the negative terminal part 24.

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.

[0002]

2. Description of the Related Art A conventional chip-shaped tantalum solid electrolytic capacitor has a structure as shown in FIGS.
That is, a dielectric oxide film formed by anodic oxidation is formed on the surface of a porous anode body that is equipped with the anode lead-out wire 1 and is made of tantalum metal that is a valve metal, and an electrolyte layer such as manganese dioxide is formed on this surface. The capacitor element 3 is formed by sequentially forming and further laminating the carbon layer and the cathode layer 2, and the capacitor element 3 is coated with the exterior resin 4 such that the anode lead wire 1 and the cathode layer 2 project at both ends. Then, the anode metal layer 6 and the cathode metal layer 7 are formed on the surface of the anode lead wire 1 protruding from the exterior resin 4, the exposed portion 2a of the cathode layer 2 and the anode lead surface 5 of the exterior resin 4, Then, the anode side solder metal layer 8 and the cathode side solder metal layer 9 were formed by immersing in solder plating or a molten solder bath.

[0003]

However, in the chip-shaped tantalum solid electrolytic capacitor configured as described above, since the anode lead wire 1 projects outward from the end surface of the exterior resin 4, the concave shape formed in the carrier tape is used. When the chip-shaped tantalum solid electrolytic capacitor housed in the housing part is taken out by an automatic mounting device and then attached to, for example, a printed circuit board, the anode lead wire 1 is caught on the inner surface of the recessed housing part and the chip-shaped tantalum solid electrolytic capacitor is mounted. There was a problem that the capacitor could not be taken out smoothly from the concave storage part.

Further, since the left and right surface areas of the external terminals composed of the anode-side solder metal layer 8 and the cathode-side solder metal layer 9 are different, for example, the Manhattan phenomenon on the printed circuit board at the time of mounting by the reflow method using cream solder. There is also a problem that a chip standing defect occurs.

The present invention solves the above-mentioned problems of the prior art, and can form external electrode terminals with high dimensional accuracy, and can reliably mount and solder with an automatic mounting apparatus. It is intended to provide an electrolytic capacitor.

[0006]

In order to achieve the above object, a chip solid electrolytic capacitor of the present invention comprises a dielectric oxide film and an electrolyte layer on the surface of an anode body made of a valve metal having an anode lead wire. A capacitor element formed by forming a cathode layer, and an exterior resin covering the capacitor element so that the anode lead wire is drawn out to one side, and the anode lead wire is bent on the anode lead wire side of the exterior resin. And a recessed portion for accommodating the anode lead-out wire, and a conductive paint electrically connected to the anode lead-out wire is embedded in the recessed portion so that the end surface on the anode side is substantially flat. A cathode terminal portion electrically connected to the cathode layer of the capacitor element is provided on the opposite side so that the surface area of the anode terminal portion and the surface area of the cathode terminal portion are substantially the same. It is.

[0007]

According to the above construction, since the anode lead wire is bent and accommodated in the recess provided on the anode lead wire side of the exterior resin, the anode lead wire projects outward from the end face of the exterior resin. In addition, a conductive paint that is electrically connected to the anode lead-out wire is embedded in the recess to provide an anode terminal part whose end surface on the anode side is almost flat.Furthermore, a capacitor is provided on the side opposite to this anode terminal part. Since the cathode terminal portion electrically connected to the cathode layer of the element is provided and the surface area of the anode terminal portion and the surface area of the cathode terminal portion are configured to be substantially the same, the left and right variations in the external electrode terminals The left and right external electrode terminals can be made to have almost the same surface area and the external electrode terminal surfaces can be made almost flat without being affected, and as a result, the chip-shaped tantalum solid by the automatic mounting device can be obtained. It can reliably be mounted solutions capacitor. Further, the chip standing defect that has occurred on the printed circuit board at the time of mounting by the reflow method using the creamy solder is significantly reduced.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. 1 is a sectional view of a chip-shaped tantalum solid electrolytic capacitor according to an embodiment of the present invention, and FIG. 2 is a perspective view of the chip-shaped tantalum solid electrolytic capacitor of FIG.

In FIGS. 1 and 2, reference numeral 11 denotes a capacitor element, which is formed on the surface of a porous anode body made of tantalum having an anode lead wire 12 by a general anodic oxidation method. An oxide film is formed, and a cathode layer 13 composed of an electrolyte layer, a carbon layer and a silver coating layer is sequentially formed on the oxide film.

Then, of the cathode layer 13 provided around the capacitor element 11, a cathode conductor layer 14 made of a conductive material is formed thickly on the surface facing the lead-out surface of the anode lead wire 12, and then the capacitor is formed. The surface of the element 11 from which the anode lead-out wire 12 is drawn out is provided with a recess 15 in which the anode lead-out wire 12 can be folded and housed.
1 and the cathode conductor layer 14 are covered with the exterior resin 16 so that the anode lead wire 12 is drawn out to one side, and thereafter,
The exposed surface 1 of the cathode conductor layer 14 is formed by cutting or grinding the side of the exterior resin 16 opposite to the anode lead wire 12.
4a is formed.

Next, in order to mechanically and electrically connect the anode lead-out wire 12 folded and housed in the recess 15 and the anode lead-out surface 17 of the exterior resin 16, the inside of the recess 15 of the exterior resin 16 on the side of the anode lead-out wire 12 is connected. A conductive paint 19 is embedded in the anode, and the anode lead-out surface 17 of the exterior resin 16 including the anode lead-out wire 12
Conductive paint 19 is also applied on the upper surface of the cathode conductor layer 14 to form a substantially flat surface, and conductive paint 20 is also applied to the exposed surface 14a of the cathode conductor layer 14 and the cathode lead-out surface 18.

The conductive paints 19 and 20 are preferably those in which the electroless plating metal is deposited on the conductive powder contained in the conductive paint. Then, an anode underlayer 21 made of an electroless plating film is formed on the conductive paints 19 and 20.
And the cathode base layer 22 are formed. After that, this is immersed in a molten solder bath or a solder plating bath to form an anode metal layer 23 and a cathode metal layer 24 made of solder metal, to produce a chip-shaped tantalum solid electrolytic capacitor.

In the above-described embodiment of the present invention, the anode lead-out wire 12 is bent and accommodated in the recess 15 provided in the exterior resin 16.
6 does not project outwardly from the end face of 6 and the cathode lead-out surface 18 of the exterior resin 16 is cut or ground in order to expose the cathode conductor layer 14. Therefore, the influence of the dimensional variation of the capacitor element 11 is affected. It is possible to form the outer shape with good dimensional accuracy without receiving the external force.

Further, since the conductive paint 19 is embedded in the recess 15, the end surface of the anode metal layer 23 is also substantially flat, and moreover, the surface area of the anode metal layer 23 serving as an external electrode terminal and the surface area of the cathode metal layer 24 are almost the same. When the chip-shaped tantalum solid electrolytic capacitor in one embodiment of the present invention housed in the recessed housing provided on the carrier tape is taken out by the automatic mounting device and attached to the printed circuit board because the same configuration is adopted. Also in the above, the chip-shaped solid electrolytic capacitor is not caught on the inner side surface inside the concave accommodating portion provided on the carrier tape as in the conventional case.

Further, the mounting of the reflow method using the cream solder has the following features as compared with the conventional one. First, cream solder is printed on the printed circuit board using screen printing, etc.The chip-shaped tantalum solid electrolytic capacitor is mounted on this printed cream-shaped solder, and the chip-shaped tantalum solid electrolytic is applied by the adhesive force of the cream solder. Hold the capacitor. Then, when this printed circuit board is flown in a reflow furnace, the cream-like solder is melted and the solder on the anode side and the cathode side of the external electrode terminal in the chip-shaped tantalum solid electrolytic capacitor is simultaneously wetted, and the solder on the anode side and the cathode side Solder pulls on each other. At this time, if the surface areas of the left and right external electrode terminals are unbalanced, chip standing defects frequently occur.

However, in the chip-shaped tantalum solid electrolytic capacitor of the present invention, since the surface areas of the external electrode terminals on the left and right sides, that is, the anode side and the cathode side, are substantially the same, even if the left and right sides are pulled evenly when the solder melts, the printed circuit board It is held on the surface so that reliable soldering can be performed. From this,
In the reflow method using the creamy solder, the chip standing failure is significantly reduced even when mounted on the circuit board, and therefore, the mounting at the time of soldering can be surely performed.

[0017]

As described above, in the chip solid electrolytic capacitor of the present invention, since the anode lead-out wire is bent and stored in the concave portion provided on the side of the anode lead-out wire of the exterior resin, the anode lead-out wire is It does not project outward from the end surface of the exterior resin, and a conductive paint that is electrically connected to the anode lead wire is embedded in the recess to provide an anode terminal part that makes the end surface on the anode side almost flat. With the surface area of the anode terminal portion by providing a cathode terminal portion electrically connected to the cathode layer of the capacitor element on the side opposite to the anode terminal portion,
Since the surface areas of the cathode terminal parts are configured to be almost the same, the left and right external electrode terminals have almost the same surface area and the external electrode terminal surfaces are not affected by the left and right variations in the external electrode terminals. It can be made almost flat, and as a result, the chip-shaped tantalum solid electrolytic capacitor can be surely mounted by the automatic mounting apparatus. In addition, the chip standing defect that has occurred on the printed circuit board during mounting by the reflow method using creamy solder is greatly reduced.

[Brief description of drawings]

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

FIG. 2 is a perspective view of the chip-shaped tantalum solid electrolytic capacitor.

FIG. 3 is a sectional view of a conventional chip-shaped tantalum solid electrolytic capacitor.

FIG. 4 is a perspective view of the chip-shaped tantalum solid electrolytic capacitor.

[Explanation of symbols]

 11 Capacitor element 12 Anode lead wire 13 Cathode layer 14 Cathode conductor layer 15 Recess 16 Exterior resin 17 Anode lead surface 18 Cathode lead surface 19 Conductive paint 23 Anode metal layer 24 Cathode metal layer

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hideo Hashimoto 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (1)

[Claims] 1. A capacitor element formed by forming a dielectric oxide film, an electrolyte layer, and a cathode layer on the surface of an anode body made of a valve metal having an anode lead wire, and the capacitor lead element as the anode lead wire. Is provided with a sheathing resin that is coated so as to be pulled out to one side, and a concave portion is provided on the anode lead-out side of the casing resin for bending and storing the anode lead-out wire, and the concave portion is electrically connected to the anode lead-out wire. Provide an anode terminal part that is filled with conductive paint so that the end surface on the anode side is almost flat, and further provide a cathode terminal part that is electrically connected to the cathode layer of the capacitor element on the side opposite to this anode terminal part. And a surface area of the cathode terminal portion and a surface area of the cathode terminal portion are substantially the same.