JP3932191B2 - Solid electrolytic capacitor - Google Patents

Description

以上作製した直後の固体電解コンデンサの性能を表２にまとめて示した。なお、全数値はｎ＝２０点の平均値である。
【００２０】
【表２】

【００２１】
【発明の効果】
本発明の固体電解コンデンサは、固体電解コンデンサ素子を複数個並列にリードフレームの一つの凸部に載置して接合しているので作製した固体電解コンデンサは高周波性能（ＥＳＲ）が良好である。
【図面の簡単な説明】
【図１】陽極リードを有する固体電解コンデンサ素子を３個並列にリードフレームに載置した状態を示す斜視図である。
【図２】固体電解コンデンサ素子自体に陽極部を有する固体電解コンデンサ素子を３個、リードフレームに載置した状態を示す斜視図である。
【図３】リードフレームに接続した固体電解コンデンサ素子を示す従来例の斜視図である。
【符号の説明】
１ リードフレーム
１ａ リードフレームの一方の凸部
１ｂ リードフレームのたほうの凸部
２ 固体電解コンデンサ素子
３ 導電体層
４ａ 陽極部
４ｂ 陽極リード
５ 外装部[0001]
[Industrial application fields]
The present invention relates to a solid electrolytic capacitor having good high frequency performance (ESR).
[0002]
[Prior art]
As shown in the perspective view of the structure of the conventional solid electrolytic capacitor, a part of the conductor layer 3 formed on the surface of one solid electrolytic capacitor element 2 and the anode lead 4b are connected to the lead frame as shown in FIG. 1 is placed on a pair of opposed convex portions 1a and 1b and bonded to each other, and then the outer frame portion 5 is formed by sealing with resin leaving only a part of the convex portion of the lead frame. Are known.
[0003]
[Problems to be solved by the invention]
On the other hand, in response to the recent trend toward higher frequencies in electronic equipment, solid electrolytic capacitors with good high frequency performance (ESR) are also desired. For example, when the solid electrolytic capacitor element is a porous sintered body, a sintered body is required. In order to maintain the strength of the bonded body, a certain amount of thickness is required. As a result, there is a drawback that high frequency performance (ESR) is not good.
[0004]
[Means for Solving the Problems]
The present invention has been made to solve the above-mentioned problems,
[1] A conductive oxide layer is formed on a surface of an anode base body made of a prismatic sintered body of valve action metal, a dielectric oxide film layer on the surface, a semiconductor layer thereon, and a conductor layer thereon. A plurality of solid electrolytic capacitor elements in which the body layer forming portion is formed are placed horizontally in parallel with a single protrusion on the lead frame without gaps, and the plurality of solid electrolytic capacitor elements are electrically connected to the conductive layer. The side surfaces of the body layer forming portion are in contact with each other with no gap, and the mounting portion of the conductor layer forming portion of all the solid electrolytic capacitor elements is directly on the lead frame, and the anode lead is the lead. A solid electrolytic capacitor having excellent high frequency performance (ESR), characterized in that it is bonded to a frame and is resin-sealed leaving a part of the lead frame;
[2] The solid electrolytic capacitor according to [1], wherein ESR at 100 KHz is excellent,
[3] The solid electrolytic capacitor according to the above [1] or [2], wherein the valve metal is tantalum, and [4] any one of the above [1] to [3], wherein the semiconductor layer is a conductive polymer compound. The above-mentioned problems have been solved by developing the solid electrolytic capacitor described in 1. above.
[0005]
The present invention will be described below with reference to the drawings. FIG. 1 is a perspective view showing an example for explaining a solid electrolytic capacitor of the present invention. FIG. 1 shows a part of a conductor layer 3 formed on a surface of three solid electrolytic capacitor elements 2 and an anode on a pair of opposed convex portions 1 a and 1 b provided on a lead frame 1. An anode lead 4b is placed, and the former is a silver paste or the like, and the latter is connected by welding or the like. The exterior portion 5 is formed by sealing a portion of the lead frame with resin.
[0006]
It is important that the three solid electrolytic capacitor elements are formed up to the conductor layer as will be described later, and then placed parallel to the convex portion of the lead frame. In this case, the three solid electrolytic capacitor elements should be placed without gaps. However, this is advantageous for reducing the size of the solid electrolytic capacitor as a whole. Note that the number of the solid electrolytic capacitor elements placed on the pair of convex portions of the lead frame is not limited to three, but a plurality. Further, it is inconvenient to place the solid electrolytic capacitor element so as to be perpendicular to the lead frame because the height of the solid electrolytic capacitor as a whole becomes high.
[0007]
The solid electrolytic capacitor element constituting the present invention is manufactured as follows. First, as the anode substrate having a valve action, for example, any metal having a valve action such as aluminum, tantalum, and an alloy using these as a substrate can be used. The shape of the anode substrate includes an aluminum plate and a tantalum sintered body.
[0008]
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 is particularly a layer made of an oxide of the valve metal itself. Preferably there is. In any case, as a method for providing the oxide layer, a conventionally known method such as an anodizing method using an electrolytic solution can be used.
[0009]
Next, a semiconductor layer is formed on the dielectric oxide film layer. A part of the part formed up to the dielectric oxide film layer is provided as the anode portion 4a as shown in FIG. 2, or as shown in FIG. As described above, the anode lead 4b is connected to a part of this portion to form an anode portion. In order to use the anode lead as the anode part, in addition to the above, a part of the anode lead may be embedded in the anode substrate in advance, for example, when the anode substrate is manufactured.
[0010]
The semiconductor layer is provided on the dielectric oxide film layer except for these anode portions, and a conductor layer is further laminated thereon to form a conductor layer forming portion. There are no particular restrictions on the type of semiconductor layer provided on the dielectric oxide film layer, and a conventionally known semiconductor layer can be used, but in particular, a semiconductor layer composed of lead dioxide or lead dioxide and lead sulfate according to the applicant's application. (Japanese Patent Laid-Open Nos. 62-256423 and 63-51621) are preferable because the produced capacitors have good high frequency performance (ESR).
[0011]
In addition, a method of forming a conductive polymer compound such as polyaniline and polypyrrole as a semiconductor layer by vapor phase polymerization using an oxidizing agent and an organic acid (Japanese Patent Laid-Open No. 62-47109), and thallium ions and persulfate ions are included. An example is a method in which tantalum oxide is chemically precipitated from the reaction mother liquor as a semiconductor layer (Japanese Patent Laid-Open No. 62-38715).
[0012]
On such a semiconductor layer, a conductive layer is formed by laminating a conventionally known conductive paste such as a carbon paste and / or a silver paste. In FIG. 1, the anode lead 4b is connected to the solid electrolytic capacitor element 2 formed as described above, and in FIG. 2, three solid electrolytic capacitor elements 2 are placed on the convex portions 1a and 1b of the pair of lead frames. The anode part 4a is formed in a part of the solid electrolytic capacitor element 2 itself.
[0013]
As described above, the solid electrolytic capacitor element formed in this way is placed on the convex portions of a pair of opposingly arranged lead frames with a plurality of directions aligned, and bonded, as shown in FIGS. As shown by the broken line portion, the outer portion 5 is formed by sealing except for a part of the convex portions 1a and 1b of the lead frame. For example, an epoxy resin, a phenol resin, an allyl ester resin, or the like is used as the sealing material of the exterior portion 5, and the sealing operation is performed by transfer molding, injection molding, cast molding, or the like.
[0014]
[Action]
A plurality of solid electrolytic capacitor elements are mounted and bonded in parallel on the convex portions of the pair of opposed lead frames, and as a result, the anode base is divided into a plurality of parts. Since the distance of the current flowing from the inside of the substrate through the conductor layer to the lead frame is shortened to some extent, the resistance value therebetween is reduced and the high frequency performance (ESR) is improved.
[0015]
【Example】
Hereinafter, the present invention will be described with reference to examples and comparative examples.
(Examples 1 and 2)
Table 1 shows a tantalum sintered body in which a dielectric oxide film layer is formed on the surface by chemical conversion treatment in an aqueous phosphoric acid solution, and a portion of the tantalum anode lead is embedded as an anode substrate. Next, the anode substrate was immersed in a mixed solution of a lead acetate trihydrate 2.4 mol / l aqueous solution and an ammonium persulfate 4.0 mol / l aqueous solution and allowed to stand at 60 ° C. for 20 minutes. This operation was performed four times to form a semiconductor layer made 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.
[0016]
On the other hand, a lead frame having a pair of protrusions, each having a thickness of 0.1 mm, a material of 42 alloy, and the protrusions on which the conductor layer forming part is mounted, as shown in Table 1, is provided. Three solid electrolytic capacitor elements were placed in parallel, the conductor layer forming part was made of silver paste, and the anode lead was welded to each electrically and mechanically, and then part of the convex part of the lead frame Was sealed with an epoxy resin to produce a solid electrolytic capacitor.
[0017]
(Examples 3 and 4)
In Examples 1 and 2, the anode substrate was made into an etched aluminum plate having a rectangular shape whose dimensions are listed in Table 1 and a dielectric oxide film layer was formed with an aqueous ammonium phosphate solution. A part of the anode substrate (2 mm from the end face) was formed. Lead dioxide is formed by electrochemically forming an anode part and further immersing a part of the anode base in a 2.0 mol / l aqueous solution of lead acetate trihydrate and a separately prepared platinum cathode. Except for the above, three solid electrolytic capacitor elements were joined in parallel in the same manner as in Examples 1 and 2, to produce a solid electrolytic capacitor.
[0018]
(Comparative Example 1)
The solid electrolytic capacitor was prepared in the same manner as in Example 1 except that the size of the tantalum sintered body in Example 1 was set to the size shown in Table 1, and one solid electrolytic capacitor element was placed on and joined to the lead frame. Produced.
[0019]
[Table 1]

Table 2 summarizes the performance of the solid electrolytic capacitor immediately after fabrication. All numerical values are average values of n = 20 points.
[0020]
[Table 2]

[0021]
【The invention's effect】
Since the solid electrolytic capacitor of the present invention has a plurality of solid electrolytic capacitor elements mounted in parallel on one convex portion of the lead frame and joined together, the produced solid electrolytic capacitor has good high frequency performance (ESR).
[Brief description of the drawings]
FIG. 1 is a perspective view showing a state in which three solid electrolytic capacitor elements having anode leads are placed 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 placed on a lead frame.
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 1b of a lead frame The convex part 2 near the lead frame Solid electrolytic capacitor element 3 Conductor layer 4a Anode part 4b Anode lead 5 Exterior part

Claims (4)

A conductor layer is formed by sequentially forming a dielectric oxide film layer on the surface of an anode base body made of a prismatic sintered body of a valve action metal having an anode lead, a semiconductor layer thereon, and a conductor layer thereon. A plurality of solid electrolytic capacitor elements formed with a plurality of portions are placed horizontally in parallel with a single protrusion on a lead frame without gaps, and the plurality of solid electrolytic capacitor elements are connected to the conductor layer. The side surfaces of the forming portions are in contact with each other with no gaps, and the mounting portions of the conductor layer forming portions of all the solid electrolytic capacitor elements are directly on the lead frame, and the anode leads are on the lead frame, respectively. A solid electrolytic capacitor excellent in high frequency performance (ESR), characterized in that it is bonded and sealed with a resin leaving a part of the lead frame.   The solid electrolytic capacitor according to claim 1, wherein ESR at 100 KHz is excellent.   The solid electrolytic capacitor according to claim 1, wherein the valve action metal is tantalum.   The solid electrolytic capacitor according to claim 1, wherein the semiconductor layer is a conductive polymer compound.

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