JP2000049049A - Chip-type solid electrolytic capacitor, manufacture thereof and lead frame used in the capacitor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a chip-type solid electrolytic capacitor with good volume efficiency, while the external size is made smaller. SOLUTION: This chip-type solid electrolytic capacitor 20 comprises a capacitor element 12, wherein an anode oxide film, a solid electrolytic layer and a cathode layer 13 comprising a carbon layer and an silver layer are sequentially formed at a square-pipe sintered pellet where an anode rod 11 is planted at one end part. Here, a cathode terminal bracket 20 is engaged with the cathode layer 13 at the end part of the capacitor element 12 on the anode rod 11 side, while an anode terminal bracket 30 extending in the direction orthogonal with respect to the anode rod 11 is fitted to the anode rod 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chip type solid electrolytic capacitor, a method of manufacturing the same, and a lead frame used for the capacitor.

[0002]

2. Description of the Related Art FIG. 5 shows a typical conventional example of a chip type solid electrolytic capacitor capable of being surface-mounted on a circuit board by an automatic machine. According to this, the capacitor 50 is a sintered pellet 50 on which an anode rod 51 is implanted.
A shows an anodic oxide film, a solid electrolyte layer 52 and a cathode layer 53.
Are sequentially formed.

[0003] A capacitor element 54 is disposed on a lead frame having an anode lead 55 and a cathode lead 57. The anode lead 55 is welded to the anode rod 51, and the cathode layer 53 is connected via a conductive adhesive 56. The cathode lead 57 is attached.

Then, in a molding die (not shown),
After the resin sheath 58 is formed around the capacitor element 54 and taken out of the molding die, the anode lead 55 and the cathode lead 57 are cut off from the lead frame, and each tip portion extends from the side to the bottom of the resin sheath 58. Each is bent into a crab foot shape.

[0005] In this way, the chip-type solid electrolytic capacitor 50 that can be surface-mounted on the circuit board 59 is manufactured.
8, the proportion of the capacitor element 50A is small, and this structure still leaves room for miniaturization.

Accordingly, the present applicant has improved the above-mentioned point and has proposed a chip-type solid electrolytic capacitor having improved volumetric efficiency in Japanese Patent Application No. Hei.
No. -230420 (JP-A-8-78288), which is shown in FIG.

That is, in this chip-type solid electrolytic capacitor 60, without attaching the anode lead 55 and the cathode lead 57 to the capacitor element 50A, the capacitor element 50A is put into a molding die, and the bottom surface of the cathode layer 53 is made of gold. A resin exterior body 58A is formed around the capacitor element 50A in close contact with the mold surface.

After taking out from the molding die, a cathode terminal plate 61 is attached to the exposed bottom surface of the cathode layer 53, and an anode terminal plate 62 in the form of a V block is attached to the anode rod 51 by welding.

[0009]

As described above, the cathode layer 5
By directly attaching the cathode terminal plate 61 to the bottom surface side of 3 and attaching the anode terminal plate 62 orthogonal to the cathode terminal plate 51 to the anode rod 51, as compared with the chip-type solid electrolytic capacitor 50 of FIG. Anode lead 5
5 and the cathode lead 57 are not routed along the resin exterior body 58, so that the size can be reduced.

However, this still leaves the following problems to be solved. First, even though the lead-out lead portion can be reduced in size and simplified and its left and right dimensions can be reduced, the height and width of the resin exterior body 58A are still formed around the capacitor element 50A. 5 is not much different from the chip-type solid electrolytic capacitor 50 of FIG. In addition, the cost is high because a molding die is required.

Next, as shown in FIG. 7, the anode terminal plate 62 is welded to the anode rod 51 of the capacitor element 50A while being attached to the lead frame 70,
Thereafter, the lead frame 70 is separated from the lead frame 70. At this time, the following problem occurs. Although only one anode terminal plate 62 is shown in FIG. 7, many of them are actually arranged side by side with respect to the strip-shaped substrate 71 of the lead frame 70 via the connecting arm 72.

The anode terminal plate 62 is formed of a substantially rectangular metal plate, and has a V-shaped groove 621 formed at one end thereof.
The opposite end surface 622 is used as a soldering surface for the circuit board 59, and conventionally, the connecting arm 7 from the end surface 622, that is, the soldering surface to the band-like substrate 71.
Two have been pulled out.

The whole of the anode terminal plate 62, the connecting arm 72 and the strip-shaped substrate 71 are stamped out of a single metal plate by pressing, and then the anode terminal plate 62 is subjected to solder plating.

Each anode terminal plate 62 has a V-shaped groove 6
21 is attached to the anode rod 51 of the capacitor element 50A from the direction orthogonal to the anode rod 51 of the capacitor element 50A.
1 is welded.

After that, the anode terminal plate 62 is cut from the root portion (the portion indicated by the broken line C) of the connecting arm 72. Not only is a cutout without solder plating exposed on the soldering surface, Burrs are formed at the cuts along with the cutting, which causes soldering failure to the circuit board 59.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and a first object of the present invention is to provide a chip type solid electrolytic capacitor capable of further reducing the external dimensions. It is in.

It is a second object of the present invention to provide a method of manufacturing a chip-type solid electrolytic capacitor capable of manufacturing a small-sized chip-type solid electrolytic capacitor at low cost.

A third object of the present invention is to provide a lead frame for a chip-type solid electrolytic capacitor provided with an anode terminal fitting in which a cutout does not appear on a soldering surface.

[0019]

In order to achieve the first object, the present invention provides an anodic oxide film on a rectangular cylindrical sintered pellet made of a valve metal powder having an anode rod implanted at one end thereof.
In a chip-type solid electrolytic capacitor having a capacitor element formed by sequentially forming a solid electrolyte layer and a cathode layer,
A cathode terminal fitting is fitted to the cathode layer at an end of the capacitor element on the side opposite to the anode rod, and the anode terminal extends on the anode rod in a direction perpendicular to the anode rod. It is characterized by fittings.

The cathode terminal fitting may be a rectangular cylinder having both ends opened or a bottomed rectangular cylinder having one surface open and a bottom on the other surface.

The cathode terminal fitting is preferably attached to the cathode layer via a conductive adhesive (for example, adhesive silver).

The anode terminal has a leg bent at a substantially right angle at an end on the soldering surface side with respect to the circuit board, and has a V-shaped groove at an end on the opposite side to the leg. Is preferred.

A reinforcing resin for mechanically connecting the anode terminal fitting and the capacitor element may be applied between the anode terminal fitting and the capacitor element.

In a preferred embodiment, the terminal fittings are preferably plated with solder.

In order to achieve the second object, the manufacturing method of the present invention is a method of producing a rectangular cylindrical sintered pellet made of a valve metal powder having an anode rod implanted at one end thereof through a hoop via the anode rod. A cathode terminal fitting having a rectangular tube portion at the lower end of the cathode layer after the capacitor element is formed by sequentially forming an anodic oxide film, a solid electrolyte layer and a cathode layer on the same sintered pellet while being suspended from the material. Then, an anode terminal fitting having a V-shaped groove at one end side is attached to the anode rod from a direction orthogonal thereto, and then welded. It is characterized in that it is cut from the site and separated from the hoop material.

In this manufacturing method, a reinforcing resin is applied between the anode terminal fitting and the capacitor element after the anode terminal fitting is welded to the anode rod and before the anode rod is cut. You may make it.

In order to achieve the third object, the present invention provides a method for connecting a plurality of anode terminal fittings attached to an anode rod implanted in a solid electrolytic capacitor element from a direction perpendicular to the anode rod to a connecting arm. In the lead frame for a chip-type solid electrolytic capacitor arranged side by side on a band-shaped substrate via the above, each of the anode terminal fittings is made of a substantially rectangular metal plate, and the above-mentioned anode rod is fitted into one end side thereof. A leg that has a V-shaped groove and is bent at substantially the right angle so as to be parallel to the circuit board is continuously provided on the other end side, and the connecting arm is pulled out from an end surface of the leg. It is characterized by having.

Each of the anode terminal fittings may be oriented so as to be parallel to the plane of the belt-like substrate via the connection arm, and conversely, each of the anode terminal fittings may be connected to the connection arm. And may be oriented so as to be orthogonal to the plane of the strip-shaped substrate via. And any aspect is included in the present invention.

[0029]

BRIEF DESCRIPTION OF THE DRAWINGS The invention will now be described in more detail with reference to an embodiment shown in the drawings.

First, the configuration of the chip type solid electrolytic capacitor 10 of this embodiment will be described with reference to the perspective view of FIG. 1 and FIG. The chip-type solid electrolytic capacitor 10 includes a rectangular cylindrical capacitor element 12 having an anode rod 11 implanted on one end surface.

The capacitor element 12 has a sintered pellet 121 of a valve metal powder (for example, tantalum powder) as a core. The sintered pellet 121 has an anodic oxide film, a solid electrolyte layer 122 made of, for example, manganese dioxide, and a carbon. A layer 131 and a silver layer 132 are sequentially formed.
Thus, the silver layer 132 is formed on the surface of the capacitor element 12.
However, since a substantial cathode layer is formed by the silver layer 132 and the carbon layer 131, the cathode layer is denoted by reference numeral 13.

A cathode terminal fitting 20 is attached to an end of the capacitor element 12 on the side opposite to the anode rod 11. In this embodiment, the cathode terminal fitting 20 is connected to the capacitor element 12.
And a conductive adhesive material 14 made of, for example, adhesive silver to the cathode layer 13.
Connected through.

In this embodiment, the metal case 21 has 42
Alloy is used, and its surface is plated with solder. In addition, instead of the bottomed metal case 21,
A rectangular cylinder whose both ends are open may be fitted to the end of the capacitor element 12. According to this, the external dimensions can be reduced by the amount without the bottom.

A washer 15 made of a heat-resistant synthetic resin such as PTFE (polytetrafluoroethylene) is fitted to the anode rod 11. The washer 15 is provided to prevent the solid electrolyte from creeping up when the solid electrolyte layer 122 is formed.

The anode rod 11 is made of, for example, a tantalum wire.
The anode terminal fitting 30 is attached to this. According to this embodiment, the anode terminal fitting 30 is provided with a rectangular plate body 31 made of a 42 alloy, and has a V-shaped groove 32 at one end thereof so as to be attachable to the anode rod 11 from a direction perpendicular thereto. Are formed. The groove 32 does not need to be V-shaped in an accurate sense, and may be, for example, C-shaped, U-shaped, or funnel-shaped.

Here, in FIGS. 1 and 2, the circuit board on which the chip type solid electrolytic capacitor 10 is mounted is PW
At the end of the plate body 31 on the side opposite to the V-shaped groove 32, leg pieces 33 bent at a right angle so as to be substantially parallel to the circuit board PW are continuously provided. A piece 33 provides a soldering surface for the circuit board PW. This plate body 31 also has a metal case 2
As in the case of No. 1, solder plating is applied.

The anode terminal fitting 30 is fixed to the anode rod 11 by, for example, laser welding. In this embodiment, a mechanical connection between the anode terminal fitting 30 and the capacitor element 12 is provided between them. Reinforcing resin 16 for strengthening is applied. As the reinforcing resin 16, a thermosetting resin or an ultraviolet curing resin is preferably used.

According to the chip-type solid electrolytic capacitor 10, the outer dimensions can be reduced as compared with the conventional one because the resin outer package is not provided.

As an embodiment of the present invention, a square cylindrical sintered pellet 121 having a length of 0.6 mm and a width of 0.9 mm and a length of 0.9 mm is used as a nucleus. And a cathode element 13 having a height and a width of 0.7 mm and a length of 1.0 mm, respectively.
And the anode terminal fittings 30 (both having a plate thickness of 0.1 mm) were attached to produce a product. The external dimensions were 0.8 mm in length and width and 1.6 mm in length.

It should be noted that the conductive adhesive 1
4 has a coating thickness of 0.05 mm, a gap between the capacitor element 12 and the anode terminal fitting 30 of 0.2 mm, and a projection length of the leg 33 of the anode terminal fitting 30 of 0.1 mm.

On the other hand, as a comparative example, a capacitor element having the same dimensions (both vertical and horizontal widths of 0.7 mm and a length of 1.0 mm) was manufactured using the resin having the configuration shown in FIG. When the chip-type solid electrolytic capacitor 60 with the exterior body 58A was manufactured and commercialized, the vertical width was 0.9 mm, the horizontal width was 0.9 mm, and the length was 1.6 mm.

Next, this chip type solid electrolytic capacitor 1
0 will be described with reference to FIG. The sintered pellet 121 is formed in advance with the anode rod 11 implanted on one end surface thereof.
Washer 15 for preventing solid electrolyte from climbing up
Is fitted.

FIG. 3 (a) shows only one sintered pellet 121, but in actuality, a predetermined number of sintered pellets 121 are first divided into, for example, SUS.
The anode bar 11 is suspended by welding to a band-shaped hoop material (support plate) 40 made of 430.

Then, the sintered pellets 1 for one lot
21 is immersed in an aqueous solution to electrochemically form an anodic oxide film (dielectric film) on their surface. Next, the step of immersing the sintered pellet 121 in an aqueous solution of manganese nitrate to impregnate the manganese nitrate, and pulling it up and thermally decomposing is repeated several times while increasing the manganese nitrate concentration. A manganese layer) 122 is formed.

Thereafter, a carbon layer 131 is formed on the solid electrolyte layer 122 to fill the irregularities of the solid electrolyte layer 122, and a silver layer 132 is formed thereon to form a capacitor element having the surface as the cathode layer 13. Get 12.

Next, a conductive adhesive 14 is placed on the bottom (lower side in FIG. 3A) of the cathode layer 13 of the capacitor element 12.
Is applied, and a square bottomed metal case 21 (cathode terminal fitting 20) is fitted and attached via the adhesive silver. Note that the metal case 21 only needs to be subjected to solder plating only on the outer surface (one surface).

After the metal case 21 is attached to the bottom of the capacitor element 12 in this manner, as shown in FIG. Installation is performed. In addition,
Although not shown in detail, in the mounting process of the anode terminal fitting 30, the capacitor element 12
1 and hung on the hoop material 40.

As described above, the V-shaped groove 32 is formed at one end of the anode terminal fitting 30, and the L-shaped groove is formed at the opposite end.
Plate body 3 having leg pieces 33 bent in a letter shape
1 in the actual manufacturing process.
Then, it is supplied to this anode terminal fitting attaching step in a state of being integrally formed with the anode terminal fitting.

That is, a plurality of anode terminal fittings 30 are juxtaposed on the strip-shaped substrate 81 of the lead frame 80 via the connecting arm 82. In this case, the connecting arm 82 is connected to the bottom surface of the leg 33 (soldering). Surface), but rather from the end surface 331 of the leg piece 33.

In this embodiment, the connecting arm 82 rises perpendicularly from the end surface 331 of the leg 33, and is bent at a predetermined portion to the side opposite to the V-shaped groove 32 at a substantially right angle to reach the edge of the band-shaped substrate 81. The plane including the plate body 31 and the plane including the band-shaped substrate 81 are parallel to each other.

As illustrated in FIG. 4, the connecting arm 82 may be raised vertically to connect the anode terminal fitting 30 to the belt-like substrate 81. In this case, the plate body The plane including 31 and the plane including the strip-shaped substrate 81 are orthogonal to each other.

In any case, each anode terminal fitting 30
Capacitor element 12 suspended on hoop material 40
Is moved in a direction perpendicular to the anode rod 11,
The anode rod 11 is fitted into the V-shaped groove 32. The anode rod 11 may be fitted into the V-shaped groove 32 by moving the capacitor element 12 side.

Then, the anode rod 11 and the anode terminal fitting 30 are welded. For this welding, for example, a laser welding machine is used. After this welding, the connecting arm 82 is cut from the end face 331 of the leg 33, and the anode terminal fitting 30 is cut off from the lead frame 80.

Next, the reinforcing resin 16 is applied between the anode terminal fitting 30 and the capacitor element 12 (see FIG. 2). As the reinforcing resin 16, for example, an epoxy-based thermosetting resin or an ultraviolet-curing resin is preferably used.

After the reinforcing resin 16 has hardened, FIG.
As shown in (c), the anode rod 11 is preferably cut along the plane of the plate body 31 of the anode terminal fitting 30, and the chip-type solid electrolytic capacitor 10 as a product is cut.
Is separated from the hoop material 40. In some cases, the reinforcing resin 16 may be applied after the anode rod 11 is cut from the hoop material 40.

According to this manufacturing method, the capacitor element 1
Since the resin exterior body is not molded around the mold 2, a molding die and a molding step are not required, and therefore, the chip-type solid electrolytic capacitor 1 can be manufactured at low cost and efficiently.
0 can be produced.

Even when the anode terminal fitting 30 is cut off from the lead frame 80, since the connecting arm 82 is cut from the end face 331 of the leg piece 33, burrs may be generated on the bottom surface (soldering surface) of the leg piece 33. Also, the solder plating does not peel off.

In the above embodiment, the anode terminal fitting 30 was used.
Is provided with a leg 33 bent in an L-shape to increase the stability at the time of mounting on the circuit board PW and secure a wider soldering surface, but the leg 33 is omitted. The anode terminal fitting 30 may have a flat plate shape. In this case, the connecting arm 82 may be raised from the flat surface of the anode terminal fitting 30.

[0059]

As described above, according to the present invention,
A chip-type solid electrolytic capacitor having smaller external dimensions and high volume efficiency can be obtained.

Further, according to the manufacturing method of the present invention, a chip type solid electrolytic capacitor having a small external dimension can be efficiently produced at low cost.

Further, according to the lead frame of the present invention, it is possible to provide an anode terminal fitting in which a cutout does not appear on a soldering surface for a chip type solid electrolytic capacitor.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an embodiment of a chip-type solid electrolytic capacitor according to the present invention.

FIG. 2 is a sectional view of the embodiment.

FIG. 3 is an explanatory view showing a manufacturing process of the chip-type solid electrolytic capacitor according to the present invention for each process.

FIG. 4 is a perspective view showing a modified example of the lead frame of the anode terminal fitting according to the present invention.

FIG. 5 is a sectional view showing a first conventional example.

FIG. 6 is a perspective view showing a second conventional example.

FIG. 7 is a perspective view showing a lead frame of an anode terminal fitting used in the second conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Chip-type solid electrolytic capacitor 11 Anode rod 12 Capacitor element 121 Sintered pellet 122 Solid electrolyte layer 13 Cathode layer 131 Carbon layer 132 Silver layer 14 Conductive adhesive material 15 Washer 16 Reinforcement resin 20 Cathode terminal fitting 21 Metal case 30 Anode terminal Hardware 31 Plate main body 32 V-shaped groove 33 Leg piece 331 End face 80 Lead frame 81 Band-shaped board 82 Connecting arm

Claims (13)

[Claims] 1. A chip type having a capacitor element in which an anodic oxide film, a solid electrolyte layer and a cathode layer are sequentially formed on a rectangular cylindrical sintered pellet made of a valve metal powder having an anode rod implanted at one end. In the solid electrolytic capacitor, a cathode terminal fitting is fitted to the cathode layer at an end of the capacitor element on the side opposite to the anode rod, and the anode rod is perpendicular to the anode rod. A chip-type solid electrolytic capacitor to which an extending anode terminal fitting is attached. 2. The chip-type solid electrolytic capacitor according to claim 1, wherein the cathode terminal fitting is formed of a rectangular cylinder having both ends opened. 3. The chip-type solid electrolytic capacitor according to claim 1, wherein the cathode terminal fitting is formed of a bottomed rectangular cylinder having one surface open and the other surface having a bottom. 4. The chip type solid electrolytic capacitor according to claim 1, wherein said cathode terminal fitting is attached to said cathode layer via a conductive adhesive. 5. The anode terminal fitting has a leg bent at a substantially right angle at an end on a soldering surface side with respect to a circuit board, and has a V-shaped groove at an end on a side opposite to the leg. The chip-type solid electrolytic capacitor according to claim 1, wherein the capacitor is provided. 6. The chip type solid according to claim 1, wherein a reinforcing resin for mechanically connecting the anode terminal fitting and the capacitor element is applied between the anode terminal fitting and the capacitor element. Electrolytic capacitor. 7. The chip-type solid electrolytic capacitor according to claim 1, wherein each of the terminal fittings is plated with solder. 8. A rectangular cylindrical sintered pellet made of a valve metal powder having an anode rod implanted at one end thereof is suspended on a hoop material via the anode rod and anodized to the sintered pellet. After forming a film, a solid electrolyte layer and a cathode layer in order to form a capacitor element, a cathode terminal fitting having a square tube portion is fitted to the lower end of the cathode layer via a conductive adhesive,
Next, after attaching and welding an anode terminal fitting having a V-shaped groove on one end side to the anode rod from a direction orthogonal to the anode rod, cutting the anode rod from a predetermined portion and separating it from the hoop material. A method for manufacturing a chip-type solid electrolytic capacitor characterized by the following. 9. After the anode terminal fitting is welded to the anode rod and before cutting the anode rod from the hoop material, a reinforcing resin is interposed between the anode terminal fitting and the capacitor element. The method for producing a chip-type solid electrolytic capacitor according to claim 8, wherein the method is applied. 10. A chip in which a large number of anode terminal fittings attached to an anode rod implanted in a solid electrolytic capacitor element from a direction perpendicular to the anode rod are arranged side by side on a strip-shaped substrate via respective connecting arms. In the lead frame for a solid electrolytic capacitor, each of the anode terminal fittings is made of a substantially rectangular metal plate, and has a V-shaped groove into which the anode rod is fitted at one end, and a V-shaped groove at the other end. Is a chip type solid electrolytic capacitor characterized in that leg pieces bent substantially at right angles to be parallel to the circuit board are continuously provided, and the connecting arm is drawn out from an end face of the leg piece. For lead frame. 11. The solid electrolytic capacitor according to claim 10, wherein each of said anode terminal fittings is oriented so as to be parallel to a plane of said strip-shaped substrate via said connecting arm. For lead frame. 12. The chip type solid electrolytic capacitor according to claim 10, wherein each of said anode terminal fittings is oriented so as to be orthogonal to a plane of said strip-shaped substrate via said connecting arm. Lead frame. 13. The lead frame for a chip-type solid electrolytic capacitor according to claim 10, wherein each of said anode terminal fittings is plated with solder.