JPH08316104A - Chip-like polarized capacitor - Google Patents

Abstract

PURPOSE: To improve the volume effective utilization rate and to obtain the high yield by forming a recess-shaped, U-shaped or V-shaped lead wire at the end of a first lead frame by forming a cut groove for engaging the wire, and so stepwise forming as to connect a second lead frame to an element. CONSTITUTION: A first lead frame, i.e., an anode lead frame 3 is so formed in an L shape as to be cross-connected with an anode lead wire 2, and the wire 2 is laser welded to the frame 3. On the other hand, a second lead frame, i.e., a cathode lead frame 4 is so formed stepwise as to be connected to at least the one surface of the periphery of the implanted surface of the wire 2 of a capacitor element 1, and the element 1 is connected to the frame 4 with conductive adhesive. A cut part such as a recess-shaped, U-shaped or V-shaped part for engaging the wire 2 is provided at the end of the frame 3. Eventually, a plastic package 5 is molded.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chip type polar capacitor.

[0002]

2. Description of the Related Art As a chip-shaped polar capacitor having a conventional frame structure, a chip-shaped solid electrolytic capacitor shown in FIG. 3 is generally known, and is embedded in an internal element, that is, a capacitor element 1. The capacitor element 1 is composed of a first lead frame or anode lead frame 3 which is joined in parallel with the anode lead wire 2 and a second lead frame or cathode lead frame 4 which is connected to the capacitor element 1. It was covered with 5.

[0003]

In the conventional chip-shaped polar capacitor, the anode lead-out wire 2 and the anode lead frame 3 are resistance-welded to each other at the overlapping portion, so that the anode lead-out wire 2 is a capacitor element 1. It is necessary to provide the overlapping welding margin in the direction in which it is pulled out more.

However, this welding margin restricts the volume effective utilization ratio (element volume / volume of the entire part) of the chip solid electrolytic capacitor in the direction of deriving the anode lead wire, that is, the length direction of the capacitor element 1. There was a problem of hindering the expansion of storage capacity.

In addition, the chip-shaped solid electrolytic capacitor is manufactured in various storage capacity products with a same product volume from a small capacity to a large capacity of about 10 times the small capacity. It is necessary to manufacture the capacitor elements 1 having different thickness dimensions H due to the difference in the manufacturing conditions (for example, the sintering temperature) of the sintered bodies made of the working metal.

When this thickness dimension H is small, it is necessary to minimize the stress on the capacitor element 1 that occurs when the anode lead frame 3 and the anode lead wire 2 of the capacitor element 1 are resistance welded. As described above, the forming depth B of the cathode lead frame 4 is shortened.

On the contrary, when the thickness dimension is large, the volume effective utilization ratio in the thickness direction of the capacitor element 1 is improved,
As shown in FIG. 5, the capacitor element 1 may be exposed from the plastic package 5 of the chip-shaped solid electrolytic capacitor, and high yield could not be obtained.

Further, if the forming depth dimension B of the cathode lead frame 4 is increased as shown in FIG. 6, the defective exposure of the capacitor element 1 is reduced. However, when the anode lead frame 3 and the anode lead-out wire 2 are resistance-welded, parallel connection cannot be made, stress is applied to the planting portion of the anode lead-out wire 2 of the capacitor element 1, leakage current failure increases, and the yield is extremely high. It will be low.

In order to solve the above-mentioned problems, the shape of the plastic package 5 is changed so that the lead-out surfaces of the anode lead frame 3 and the cathode lead frame 4 are higher than that of the plastic package 5 of FIG. 5, as shown in FIG. To do. That is, it is necessary to set the parting line of the plastic package higher than the conventional one, and newly set the molding die for the plastic package 5 with H1 <H2.

The plastic package shape of the chip solid electrolytic capacitor shown in FIG. 7 can cope with the case where the thickness dimension of the capacitor element 1 described at the beginning is small as shown in FIG. The center of gravity of was shifted to a high position, and there was a high possibility of inducing a tombstone phenomenon in the stability when mounted on the board, which was not a desirable structure.

As described above, even if the outer dimensions are the same, the molding die for the plastic package 5 requires at least two dies shown in FIGS. 3 and 7 depending on the thickness of the capacitor element 1. In the 5 molding process, in addition to the enormous amount of capital investment, it is necessary to replace the plastic package 5 molding die between lots having different thickness dimensions of the capacitor element 1, which requires a lot of man-hours. In addition, since it takes time to replace it, the productivity is extremely poor.

The present invention solves the above problems, and has an excellent volume effective utilization ratio to the conventional chip-shaped polar capacitor shown in FIG. 3, and one plastic package 5 molding die It is an object of the present invention to provide a chip-shaped polar capacitor which can be manufactured regardless of the size of the element and has a very excellent productivity of obtaining a high yield.

[0013]

In order to achieve the above object, a chip-shaped polar capacitor of the present invention comprises an element having a lead wire, a first lead frame cross-joining the lead wire, and the element. In a polar capacitor consisting of a second lead frame connected to the device and a plastic package covering the element, a cut groove for fitting the lead-out line such as a U-shape, V-shape or the like at the tip of the first lead frame. Are formed and formed, and the second lead frame is formed stepwise so as to be connected to the element.

[0014]

According to the above construction, the first lead frame is cross-connected to the lead wire of the element, and the second lead frame is formed in a stepwise manner so as to be connected to the element. Compared with conventional products, it is possible to secure an excellent volume effective utilization ratio in the length direction and thickness direction of the element, and the plastic depth of the plastic package is adjusted according to the element size by the forming depth of the first and second lead frames. Since the position of the element can be changed inside, it is possible to prevent the internal element from being exposed and become a defective product, and it is possible to optimize the center of gravity of the product. Furthermore, since one plastic package molding die can support chip-shaped polar capacitors of various element sizes, the capital investment for the plastic package molding die can be minimized, and the plastic package can be adjusted according to the element size. It is possible to reduce the number of man-hours for exchanging the molding die and to eliminate the time required for exchanging the die, and it is possible to obtain extremely excellent productivity.

[0015]

[Embodiment 1] Hereinafter, an embodiment of the present invention in which a chip solid electrolytic capacitor is manufactured will be described with reference to the drawings.

FIG. 1 is a cross-sectional view showing an embodiment of a chip solid electrolytic capacitor according to the present invention, and FIG. 2 is a perspective view of a main part of the same capacitor during manufacturing.

In FIG. 1, the capacitor element 1 is formed by sequentially forming a dielectric oxide film, an electrolyte layer, a carbon layer, and a cathode layer on the surface of a sintered element made of a valve metal having an anode lead wire 2. .

In joining the capacitor element 1 to the lead frame, the first lead frame, that is, the anode lead frame 3 can be cross-joined to the anode lead wire 2.
After forming into an L shape, the anode lead wire 2 and the anode lead frame 3 are laser-welded, while the second lead frame, that is, the cathode lead frame 4 is connected to the capacitor element 1.
After the anode lead wire 2 was formed stepwise so as to be connected to at least one of the peripheral surfaces of the planting surface, the capacitor element 1 and the cathode lead frame 4 were connected with a conductive adhesive.

Further, as shown in FIG. 2, a V-shaped cut portion into which the anode lead wire is fitted is provided at the tip of the anode lead frame 3. The cut portion may have any shape such as a U shape or a concave shape into which the anode lead wire 2 can be fitted.

At this time, the thickness dimension H of the capacitor element 1
Accordingly, the forming jig for changing the L-shaped forming depth A of the anode lead frame 3 and the stepped forming depth B of the cathode lead frame 4 described above is simply replaced, and as described later, The same molding die can be used to accommodate various sizes of the capacitor element 1.

Subsequently, a plastic package 5 was molded by a transfer molding method so that the anode lead frame 3 and the cathode lead frame 4 were pulled out to the outside.

In the chip-shaped solid electrolytic capacitor constructed as described above, since the anode lead frame 3 is cross-joined with the anode lead wire, the loss volume consumed in the frame welding portion in the plastic package 5 is extremely large. The size of the capacitor element 1 can be reduced, and the capacitor element 1 having a size about 1.3 times larger than that of the conventional chip solid electrolytic capacitor shown in FIG. 3 can be accommodated.

FIG. 9 and FIG. 10 are examples of manufacturing the above-mentioned chip-shaped solid electrolytic capacitor when the thickness dimension H of the capacitor element 1 is small and large, respectively. According to the method of the invention, by changing only the forming depths A and B of the anode lead frame 3 and the cathode lead frame 4, the same plastic package 5 molding die can prevent the occurrence of defective exposure of the device and the product. It becomes possible to optimize the center of gravity, it is possible to cope with capacitor elements of various sizes, the capital investment amount for the plastic package 5 molding die can be minimized, and the size of the conventional capacitor element 1 allows Since it was necessary to replace the plastic package 5 molding die, the number of man-hours and the replacement time are unnecessary, which is excellent. It was it was possible to obtain a productivity.

[0024]

Second Embodiment Next, another embodiment of the present invention will be described with reference to FIG.
Described in.

The basic structure is the same as that of the first embodiment. In the embodiment of FIG. 1, the lead-out surface of the cathode lead frame 4 is set lower than the upper surface of the capacitor element 1, but in the present embodiment, it is set upward.

In this case, as shown in FIG. 12, the forming depth of the anode lead frame 3 and the cathode lead frame 4 can be changed by the same plastic package 5 molding die regardless of the size of the element. In addition, it is possible to obtain a chip-shaped solid electrolytic capacitor having an excellent volume effective utilization rate as compared with the conventional example at the beginning, that is, the chip-shaped solid electrolytic capacitor shown in FIG.

Although the above two embodiments have been described with respect to the chip-shaped solid electrolytic capacitor, the following effects can be similarly obtained with other chip-shaped polar capacitors.

[0028]

As described above, in the chip-shaped solid electrolytic capacitor of the present invention, the first lead frame cross-joins the lead wire of the element, and has at least one forming part in the plastic package, Since the second lead frame has a stepped forming part so as to be connected to the element, it has an excellent volume effective utilization ratio in the length direction and the thickness direction of the element as compared with the conventional product shown in FIG. While it can be secured, by forming depth of the first and second lead frames, according to the size of the element, it is possible to change the position of the element in the plastic package, prevent the occurrence of poor exposure of internal elements, The center of gravity of the product can be optimized, and one plastic package molding die can be used for chip-shaped electronic components of various element sizes. Therefore, the capital investment for the plastic package molding die can be minimized, and
It is possible to reduce the number of man-hours for exchanging the plastic package molding die depending on the element size, and to eliminate the time required for the exchanging, so that it is possible to obtain extremely excellent productivity.

[Brief description of drawings]

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

FIG. 2 is a perspective view of a main part of the chip solid electrolytic capacitor of FIG. 1 during manufacturing.

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

FIG. 4 is a cross-sectional view of a conventional chip-shaped solid electrolytic capacitor when the capacitor element 1 has a small thickness.

FIG. 5 is a cross-sectional view of a conventional chip-shaped solid electrolytic capacitor when a capacitor element 1 has a large thickness and is exposed from a plastic package 5.

FIG. 6 is a cross-sectional view in the case where the thickness dimension of the capacitor element 1 in the conventional chip solid electrolytic capacitor is large and the anode lead wire 2 is not connected in parallel to the anode lead frame 3.

FIG. 7 is a cross-sectional view of another example of a conventional chip-shaped solid electrolytic capacitor.

8 is a cross-sectional view in the case where the thickness dimension of the capacitor element 1 in FIG. 7 is small.

9 is a cross-sectional view when the thickness dimension of the capacitor element 1 of FIG. 1 according to the present invention is small.

10 is a sectional view of the capacitor element 1 of FIG. 1 according to the present invention having a large thickness.

FIG. 11 is a sectional view showing another embodiment of the chip solid electrolytic capacitor according to the present invention.

12 is a cross-sectional view when the thickness dimension of the capacitor element 1 in the embodiment of FIG. 11 is small.

[Explanation of symbols]

 1 Capacitor element 2 Anode lead wire 3 Anode lead frame 4 Cathode lead frame 5 Plastic package

Claims (1)

[Claims] 1. An element comprising a lead wire, a first lead frame which is cross-joined with the lead wire, a second lead frame which is connected to the element, and a plastic package which covers the element. In the polar capacitor, a cut groove for fitting the lead wire is formed at the tip of the first lead frame for forming, and the second lead frame is formed in a stepwise shape so as to be connected to the element. Chip-shaped polar capacitor.