JP2002110462A - Solid-state electrolytic capacitor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase the flexibility of a lead frame without remarkably changing the manufacturing facility of a capacitor while using the same material as before. SOLUTION: The lead frame 9 projecting from a housing 7 is bent and consists of a first piece 91 extended downward from a projecting part from the housing 7, and a second piece 92 extended inward from the lower end of the first piece 91. The position where the lead frame 9 is projecting from the housing 7 is deviated 0.05 to 0.4 times the thickness H of the housing 7 from the center C in the thickness direction of the housing 7.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a chip type solid electrolytic capacitor, and more particularly to a thin solid electrolytic capacitor having a thickness of 2 mm or less.

[0002]

2. Description of the Related Art FIG. 7 is a perspective view of a chip type solid electrolytic capacitor, and FIG. 8 is a sectional view of FIG. The solid electrolytic capacitor is constructed by covering a capacitor body (8) with a housing (7) made of a synthetic resin, specifically a thermosetting resin such as an epoxy resin, and electrically connected to the capacitor body (8). The two lead frames (9) and (90) thus project outward from both sides of the housing (7). The lead frames (9) and (90) are made of an alloy containing iron and nickel as main components. housing
The dimension (7) has a width W of 3 to 7 mm and a depth L of 2.8 to 5 mm, but is not limited to this dimension. The capacitor body (8) is formed as follows. First,
An anode lead (2) is bonded or bonded to an anode (1) which is a sintered body of valve metal, and a dielectric oxide film (3) is applied to the anode (1).
And a cathode layer (4) made of a solid conductive material of MnO ₂ (manganese dioxide) and a conductive organic compound on the dielectric oxide film (3) to form a capacitor element (5) as is well known. ). Here, the valve metal refers to a metal on which an extremely dense and durable dielectric oxide film is formed by electrolytic oxidation treatment. In addition to Al and Ta, Ti (titanium), Nb (niobium), and the like are applicable. I do. Examples of the conductive organic compound include conductive polymers such as polypyrrole, polythiophene, polyaniline, and polyfuran, and TCNQ (7,
(7,8,8-tetracyanoquinodimethane) complex salt, inorganic semiconductor and the like. Cathode layer of capacitor element (5)
A capacitor body (8) is provided by forming a carbon layer (6) on (4) and forming a silver paste layer (60) on the carbon layer (6).

Next, one lead frame (9) is attached to the anode lead wire (2) by resistance welding or the like, and the other lead frame (90) is attached to the silver paste layer (60) with a silver adhesive. The lead frames (9) and (90) are covered with a synthetic resin housing (7) except for the portions that become the external electrodes, and the lead frames (9) and (90) projecting outward from the housing (7) are bent. I do. The lead frame (9) (90) has a first piece (9) extending downward from a protrusion from the housing (7).
1) and a second piece (92) extending inward from the lower end of the first piece (91)
And the second piece (92) is soldered to a mounting board (not shown). The protruding part of the lead frame (9) from the housing (7) is located at the center in the thickness direction of the housing (7). To bend the lead frame (9) (90) to form the first piece (91) and the second piece (92), bend the lead frame (9) downward as shown in FIG. Utensils (7
5) is deployed, and the roller (76) is pressed from above the lead frame (9) (90) to bend the second piece (92). Thereafter, if the first piece (91) is bent downward, the second piece (92) is provided on the lower surface of the housing (7) as shown in FIG.
Power is supplied to the lead frames (9) and (90) to perform aging to complete the capacitor.

[0004]

Some conventional solid electrolytic capacitors have a thickness H of about 4 mm in FIG. 8 and a length (a in FIG. 9) of the first piece (91) of about 2 mm. With this length, the second piece (92) could be bent without any trouble. However, in recent years, there has been a demand for a solid electrolytic capacitor having a thin housing (7) in order to reduce the size of surface mount components. The thickness of the housing (7) is about 2 mm,
The length of (91) is reduced to about 1 mm. Since the first piece (91) is short, it is difficult to bend the second piece (92), and as shown in FIG. 9, the first piece (91) bends upward when a bending moment is applied. In this case, as shown in FIG. 11, the second piece (92) does not contact the lower surface of the housing (7), and the housing (7) floats when soldered to the mounting board. Or, FIG.
As shown in (2), even if the second piece (92) can be bent, there is a possibility that the maximum distance b between the first pieces (91) and (91) does not fall within a prescribed dimension. In addition, when a large load is applied to securely bend the first piece (91) and the second piece (92), the capacitor body (8)
Unnecessary force is applied to the capacitor, which may change the characteristics of the capacitor. In addition, a significant change in the equipment for manufacturing the capacitor in order to improve the bendability of the lead frames 9 and 90 should be avoided in order to reduce equipment investment costs and the like. As described above, the lead frames 9 and 90 are formed from an alloy of iron and nickel. Alternatively, the lead frames 9 and 90 may be formed of soft copper to improve bendability.
However, copper tends to rust and lacks strength,
There is a drawback that it is weak against impact and the like. SUMMARY OF THE INVENTION An object of the present invention is to improve the easiness of bending a lead frame without largely changing the equipment for manufacturing a capacitor, while keeping the conventional material.

[0005]

The lead frame (9) protruding from the housing (7) is bent, and the first piece (91) extending downward from the protruding portion from the housing (7) and the first piece (91). Piece (9
1) and a second piece (92) extending inward from the lower end. The projecting position of the lead frame (9) from the housing (7) is shifted upward from the center in the thickness direction of the housing (7) by 0.05 to 0.4 times the thickness H of the housing (7). .

[0006]

[Function and effect] Housing (7) of lead frame (9)
From the center in the thickness direction of the housing (7) is 0.05 to 0.4 times the thickness H of the housing (7), that is, half the thickness H / 2 of the housing (7). 0.1
It is shifted upward by 0.8 times. Thereby, even if the housing (7) is thinned, the length of the first piece (91) can be provided as long as possible, and when the second piece (92) is formed,
The first piece (91) can be prevented from being bent and deformed. Further, since it is not necessary to apply a large load when bending the second piece (92), there is no danger that the characteristics of the capacitor will change. Further, as will be described later, the housing of the lead frame (9)
To change the protruding position from (7), it is necessary to newly manufacture a mold for molding the housing (7), but to change other manufacturing equipment, it is insignificant to adjust the equipment. Just change. Therefore, it is not necessary to significantly change the manufacturing equipment for the capacitor.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an example of the present invention will be described in detail with reference to the drawings. The present embodiment is characterized in that the projecting position of the lead frames (9) and (90) from the housing (7) is shifted upward from the center in the thickness direction of the housing (7). 5) and the capacitor body (8) are the same as the conventional one. 1 to 6 are sectional views of a solid electrolytic capacitor. The protruding position B of the lead frames 9 and 90 shown in FIG. 1 from the housing 7 is approximately 0.1 to 0.8 mm from a line C which is the center in the thickness direction of the housing 7.
It is shifted upward. Since the thickness of the housing (7) is 2 mm, the protruding position B is 0.0 mm of the thickness H of the housing (7).
It is shifted upward by 5 to 0.4 times, that is, 0.1 to 0.8 times the half thickness H / 2 of the housing (7). The thickness of the lead frames 9 and 90 is about 0.1 mm. Therefore, the protruding position B is shifted upward from the center in the thickness direction of the housing (7) by 1 to 8 times the thickness of the lead frame (9) (90).

As a result, the thickness of the housing (7) becomes about 2
mm, the length of the first piece (91) can be provided as long as possible, and when forming the second piece (92),
The risk that the piece (91) bends and deforms can be prevented. Also, the second piece
Since it is not necessary to apply a large load during the bending of (92), there is no possibility that the characteristics of the capacitor will change. The protruding position B is set at 0. 0 from the center C in the thickness direction of the housing (7).
If the deviation is less than 1 mm, it is difficult to bend the second piece (92). Further, when the protruding position B is shifted from the center C in the thickness direction of the housing (7) by more than 0.8 mm,
The thickness of the housing (7) covering the lead frames (9) and (90) is too thin, and the housing (7) is easily peeled off, so that the lead frames (9) and (90) are easily exposed.
Therefore, the amount of deviation of the protruding position B from the central portion C is 0.1 to 0.1.
It is set to 0.8 mm.

The housing (7) of the lead frame (9) (90)
In order to shift the projecting position from the center upward in the thickness direction of the housing (7), the embodiment shown in FIGS. In FIG. 1, one lead frame (9) is in contact with the anode lead wire (2) without deformation, and the other lead frame (90) has a silver paste layer (60).
The step (93) is formed by performing a bending process between a portion in contact with the first piece (91). As a result, the projecting positions B of both lead frames 9 and 90 are at the same height.

Although the anode lead wire (2) and the lead frame (9) are welded, the welding pressure is set low during this welding. In the conventional example shown in FIG. 8, the welding pressure is increased,
Specifically, set to 1-2 kg / cm ^2, and set the anode lead wire
The lead frame (9) is inserted into (2). On the other hand, in the example shown in FIG. 1, since the welding pressure is set low, the lead frame (9) does not sink into the anode lead (2). This allows the housing of the lead frame (9)
The protruding position B from (7) is shifted upward from the center in the thickness direction of the housing (7). Although the welding pressure is weakened, there is a concern that the joining force between the anode lead wire (2) and the lead frame (9) is insufficient. However, the applicant compensates for the insufficient joining force by adjusting the welding time and welding current. Make sure you can. The first piece (91) shown in FIG. 1 is bent downward to form a surface mountable shape as shown in FIG.

In the example shown in FIG. 3, the silver paste layer (6
No step (93) is formed on the lead frame (90) in contact with (0),
Step (9) is attached to the lead frame (9) in contact with the anode lead (2).
3) is formed. According to this structure, the lead frame
(9) It is possible to shift the projecting position B of (90) upward from the center in the thickness direction of the housing (7) by 0.7 to 0.8 mm, and the bending process of the lead frame (9) (90) can be performed. It will be easier.
The first piece (91) shown in FIG. 3 is bent downward to form a surface mountable shape as shown in FIG.

Further, as shown in FIG. 5, a step portion (93) may be formed on both lead frames (9) and (90). Further, as shown in FIG. 6, the anode lead wire (2) may be bent slightly upward. With such a structure in which the first piece (91) is provided as long as possible, the lead frame (9) (90) is
Since the pieces (92) can be easily formed and the bending load during the bending can be reduced, there is no possibility that the characteristics of the capacitor will change.

In this embodiment, the lead frame (9) (90)
In order to change the protruding position of the housing 7 from the housing 7, it is necessary to newly manufacture a mold for molding the housing 7.
However, changes to other manufacturing equipment need only be minor changes, such as adjustments to equipment, such as changes in welding conditions, as described above. Therefore, there is no need to significantly change the manufacturing equipment for capacitors.

The description of the above embodiments is for the purpose of illustrating the present invention and should not be construed as limiting the invention described in the appended claims or reducing the scope thereof. Further, the configuration of each part of the present invention is not limited to the above-described embodiment, and it is needless to say that various modifications can be made within the technical scope described in the claims.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a solid electrolytic capacitor, showing a lead frame being formed.

FIG. 2 is a sectional view of the solid electrolytic capacitor according to the first embodiment;

FIG. 3 is a cross-sectional view of another example of a solid electrolytic capacitor;
This shows the lead frame being formed.

FIG. 4 is a sectional view of the solid electrolytic capacitor according to the first embodiment;

FIG. 5 is a cross-sectional view of another example of a solid electrolytic capacitor.

FIG. 6 is a sectional view of another example of a solid electrolytic capacitor.

FIG. 7 is a perspective view of a conventional chip-type solid electrolytic capacitor.

FIG. 8 is a cross-sectional view of FIG. 7 cut along a plane including a line AA.

FIG. 9 is a cross-sectional view showing bending of a lead frame.

FIG. 10 is a sectional view showing a molding failure state of the lead frame.

FIG. 11 is a sectional view showing a molding failure state of the lead frame.

[Explanation of symbols]

 (7) Housing (8) Capacitor body (9) Lead frame (91) First piece (92) Second piece

Claims (2)

[Claims] 1. A lead frame (9) serving as an external electrode is electrically connected to a capacitor body (8).
(8) and the base end of the lead frame (9) to the housing (7)
The lead frame (9) projecting from the housing (7) is bent, and the first piece (91) and the first piece (91) extending downward from the projecting portion from the housing (7). And a second piece (92) extending inward from the lower end of the solid electrolytic capacitor, wherein the lead frame (9) protrudes from the housing (7) at a position B.
Is a solid electrolytic capacitor which is displaced upward from the central portion C in the thickness direction of the housing (7) by 0.05 to 0.4 times the thickness H of the housing (7). 2. The projecting position B of the lead frame (9) from the housing (7) is shifted upward from the center in the thickness direction of the housing (7) by 1 to 8 times the thickness of the lead frame (9). The solid electrolytic capacitor according to claim 1, wherein