JPH05234829A - Solid electrolytic capacitor - Google Patents

Abstract

PURPOSE:To make the high-frequency performance of the title capacitor good by a method wherein a plurality of solid electrolytic capacitor elements are mounted in parallel on, and bonded to, one pair of protrusion parts on a lead frame provided with the pair of protrusion parts arranged so as to be faced and they are sealed with a resin by partly leaving the protrusion parts on the lead frame. CONSTITUTION:Three solid electrolytic capacitor elements in which up to conductor layers have been formed are mounted in parallel on a lead frame provided with one pair of protrusion parts on which conductor-layer formation parts are mounted, whose thickness is 0.1mm and whose material is 42 Alloy. The conductor-layer formation parts are formed of a silver paste; individual anode leads are connected electrically and mechanically by a welding operation. After that, the protrusion parts on the lead frame are left partly; they are sealed with an epoxy resin; a solid electrolytic capacitor is manufactured. As a result, an anode base body at the capacitor is divided into a plurality of anode base bodies. The distance over which an electric current flows to the lead frame through the conductor layers from the anode base bodies is made short to a certain extent. As a result, a resistance value between them is reduced, and the high-frequency performance of the capacitor becomes good.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solid electrolytic capacitor having good high frequency performance.

[0002]

2. Description of the Related Art A conventional solid electrolytic capacitor has a structure in which a portion of a conductor layer 3 formed on the surface of one solid electrolytic capacitor element 2 and an anode are shown in FIG. The leads 4b are placed on the pair of projecting portions 1a, 1b arranged opposite to each other on the lead frame 1 and bonded to each other. Then, only a part of the projecting portion of the lead frame is sealed with a resin and the exterior portion 5 Is known to have formed.

[0003]

On the other hand, in response to the high frequency of electronic equipment in recent years, a solid electrolytic capacitor having good high frequency performance is desired. In the case of the bonded body, a certain amount of thickness is required to maintain the strength of the sintered body, and as a result, the high frequency performance is not good.

[0004]

The present invention has been made to solve the above-mentioned problems, and its gist is to have a dielectric oxide on the surface of an anode substrate made of a valve metal having an anode portion. A plurality of solid electrolytic capacitor elements in which a film layer, a semiconductor layer on the film layer, and a conductor layer on the film layer are sequentially formed,
A solid electrolytic capacitor which is placed in parallel with and bonded to the convex portions of a lead frame having a pair of convex portions arranged to face each other, and which is sealed with a resin leaving a part of the convex portions of the lead frame. It is in.

The present invention will be described below with reference to the drawings. FIG. 1 is a perspective view showing an example for explaining the solid electrolytic capacitor of the present invention. FIG. 1 shows a pair of projecting portions 1 a, 1 b provided on the lead frame 1 and facing each other.
And a part of the conductor layer 3 formed on the surface of each of the three solid electrolytic capacitor elements 2 and an anode lead 4 serving as an anode part.
b is placed, the former is a silver paste or the like, and the latter is a state in which they are connected by welding or the like. Then, a part of the lead frame is left and sealed with a resin to form the exterior part 5.

It is essential that the three solid electrolytic capacitor elements are formed in parallel to the convex portions of the lead frame after being formed up to the conductor layer, as will be described later. It is convenient to place the solid electrolytic capacitor for miniaturization. The number of solid electrolytic capacitor elements mounted on the pair of convex portions of the lead frame is not limited to three and may be plural. Further, it is inconvenient to stack and mount the solid electrolytic capacitor element vertically to the lead frame because the height of the solid electrolytic capacitor as a whole becomes high.

The solid electrolytic capacitor element constituting the present invention is manufactured as follows. First, as the anode substrate having a valve action, for example, aluminum, tantalum,
Also, any metal having a valve action such as an alloy using these as a substrate can be used. And as the shape of the anode substrate,
There are aluminum plates and sintered tantalum.

The dielectric oxide film layer provided on the surface of the anode substrate may be a layer of another dielectric oxide provided on the surface of the valve metal, but especially from the oxide of the valve metal itself. It is preferable that the layer is In any case, as a method for providing the oxide layer, a conventionally known method such as an anodization method using an electrolytic solution can be used.

Next, a semiconductor layer is formed on the dielectric oxide film layer. A part of the portion formed up to the dielectric oxide film layer is provided as the anode portion 4a as shown in FIG. The anode lead 4b is connected to a part of this portion as shown in FIG. In order to use the anode lead as the anode part, other than the above, for example, when the anode substrate is manufactured, a part of the anode lead may be embedded in the anode substrate in advance.

The semiconductor layer is provided on the dielectric oxide film layer except for those portions which are anode portions, and a conductor layer is further laminated thereon to form a conductor layer forming portion.
The type of the semiconductor layer provided on the dielectric oxide film layer is not particularly limited, and a conventionally known semiconductor layer can be used. In particular, a lead dioxide filed by the applicant of the present application or a semiconductor layer composed of lead dioxide and lead sulfate. (Japanese Patent Laid-Open No. 62-256423
JP-A-63-51621) is preferable because the high-frequency performance of the produced capacitor is good.

Further, a method of forming a conductive polymer compound such as polyaniline or polypyrrole as a semiconductor layer by gas phase polymerization using an oxidizing agent and an organic acid (JP-A-62-47).
No. 109), or a method of chemically depositing thallium oxide as a semiconductor layer from a reaction mother liquor containing thallium ions and persulfate ions (Japanese Patent Laid-Open No. 62-38715).

On such a semiconductor layer, a conductor layer is formed by laminating a conventionally known conductive paste such as carbon paste and / or silver paste. In FIG. 1, an anode lead 4b is connected to the solid electrolytic capacitor element 2 thus formed, and in FIG. 2, three solid electrolytic capacitor elements 2 are formed by a pair of convex portions 1a of the lead frame,
1b is a perspective view of the solid electrolytic capacitor element 2 itself, on which a positive electrode portion 4a is formed.

As described above, the solid electrolytic capacitor element thus formed is aligned in a plurality of directions and placed on the convex portions of the pair of lead frames arranged so as to face each other.
The exterior portion 5 is formed by joining and sealing the lead frame except a part of the convex portions 1a and 1b as shown by the broken line portions in FIGS. An epoxy resin, a phenol resin, an allyl ester resin, or the like is used as a sealing material for the outer casing 5, and the sealing work is performed by transfer molding, injection molding, cast molding or the like.

[0014]

A plurality of solid electrolytic capacitor elements are placed and joined in parallel on the convex portions of a pair of lead frames arranged so as to face each other, and as a result, the anode substrate is divided into a plurality of parts. Therefore, the distance of the current flowing from the inside of the anode substrate through the conductor layer to the lead frame is shortened to some extent, so that the resistance value between them is reduced and the high frequency performance is improved.

[0015]

EXAMPLES The present invention will be described below with reference to Examples and Comparative Examples. Examples 1 and 2 A tantalum sintered body, in which a dielectric oxide film layer was formed on the surface by chemical conversion treatment in a phosphoric acid aqueous solution and a part of a tantalum anode lead was embedded, was prepared as an anode substrate, and its dimensions are shown in Table 1. It was shown to. Next, the anode substrate was immersed in a mixed solution of a 2.4 mol / l aqueous solution of lead acetate trihydrate and a 4.0 mol / l aqueous solution of ammonium persulfate and left at 60 ° C. for 20 minutes. This operation was repeated 4 times to form a semiconductor layer composed of lead dioxide and lead sulfate. Next, a carbon paste and a silver paste were sequentially laminated on the semiconductor layer to form a conductor layer.

On the other hand, a separately prepared lead frame having a thickness of 0.1 mm, a material of 42 alloy and a pair of convex portions in which the dimensions of the convex portions on which the conductor layer forming portion is mounted are listed in Table 1 are used. 3 solid electrolytic capacitor elements formed up to the body layer
Placed in parallel, the conductor layer forming part is made of silver paste, and the anode leads are electrically and mechanically connected by welding, respectively,
A solid electrolytic capacitor was produced by sealing a part of the lead frame with epoxy resin while leaving a part of the projecting part.

Examples 3 and 4 In Examples 1 and 2, the anode substrate was a rectangular aluminum plate having dimensions described in Table 1 and formed into an etched aluminum plate having a dielectric oxide film layer formed with an aqueous solution of ammonium phosphate. A part (2 mm from the end face) is used as the anode part, and the semiconductor layer is further immersed in a 2.0 mol / l aqueous solution of lead acetate trihydrate to immerse a part of the anode substrate in order to generate electricity between a separately prepared platinum cathode. Three solid electrolytic capacitor elements were joined in parallel in the same manner as in Examples 1 and 2 except that they were chemically formed into lead dioxide to produce a solid electrolytic capacitor.

Comparative Example 1 The same as Example 1 except that the size of the tantalum sintered body was set to the size shown in Table 1 and one solid electrolytic capacitor element was placed on the lead frame and bonded. Then, a solid electrolytic capacitor was produced.

[0019]

[Table 1] The performance of the solid electrolytic capacitor immediately after the above production is summarized in Table 2. All numerical values are average values of n = 20 points.

[0020]

[Table 2]

[0021]

In the solid electrolytic capacitor of the present invention, a plurality of solid electrolytic capacitor elements are placed in parallel on one convex portion of the lead frame and joined, so that the solid electrolytic capacitor produced has good high frequency performance. is there.

[Brief description of drawings]

FIG. 1 is a perspective view showing a state where three solid electrolytic capacitor elements having anode leads are mounted in parallel on a lead frame.

FIG. 2 is a perspective view showing a state in which three solid electrolytic capacitor elements each having an anode portion are mounted on a lead frame in the solid electrolytic capacitor element itself.

FIG. 3 is a perspective view of a conventional example showing a solid electrolytic capacitor element connected to a lead frame.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Lead frame 1a One convex part of the lead frame 1b The other convex part of the lead frame 2 Solid electrolytic capacitor element 3 Conductor layer 4a Anode part 4b Anode lead 5 Exterior part

Claims (1)

[Claims] 1. A plurality of solid electrolytic capacitor elements in which a dielectric oxide film layer is formed on the surface of an anode substrate made of a valve metal, which has an anode portion, a semiconductor layer is formed thereon, and a conductor layer is formed thereon. Are mounted and joined in parallel to the convex portions of the lead frame having a pair of opposed convex portions, and are sealed with a resin while leaving a part of the convex portions of the lead frame. Solid electrolytic capacitor characterized by.