JP2950587B2 - Solid electrolytic capacitor and method of manufacturing the same - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a solid electrolytic capacitor, and more particularly to a plate-shaped solid electrolytic capacitor using an organic conductive compound.

[Conventional technology]

In recent years, downsizing of electronic components has been promoted due to demands for downsizing of electronic devices and improvement of mounting efficiency on printed circuit boards. Accordingly, miniaturization of electrolytic capacitors has been promoted.

However, in the case of an electrolytic capacitor, particularly an electrolytic capacitor using an electrolytic solution as an electrolyte, it is necessary to seal the electrolytic solution in a certain storage space.

Therefore, although various proposals have been made to reduce the size of the electrolytic capacitor, for example, the height dimension from the printed circuit board is limited to about 10 mm to 4 mm, which is equivalent to the outer dimension of the ceramic capacitor of 1 mm. It was extremely difficult to realize an electrolytic capacitor of about 3 mm.

On the other hand, a solid electrolytic capacitor that does not use an electrolyte generally has a solid electrolyte layer made of, for example, manganese dioxide or the like formed on an anode body made of tantalum or the like having an oxide film layer formed on its surface, and further has a carbon paste and It has a configuration in which a conductor layer made of silver paste or the like is formed. Such a carrier electrolytic capacitor is relatively easy to miniaturize because the electrolyte is solid, and can be miniaturized.

[Problems to be solved by the invention]

However, the capacitance range of the conventional solid electrolytic capacitor is limited to about 0.1 to 10 μF. Further, although its impedance characteristic is superior to that of an electrolytic capacitor using an electrolytic solution, it is still insufficient compared with a ceramic capacitor or the like, and the cost increases when tantalum is used for the anode body.

In addition, the mounting efficiency of electronic components in electronic devices is limited due to restrictions due to the external dimensions of the electronic components themselves,
For example, useless space such as a gap between electronic components or a gap between an electronic component and a housing still prevents miniaturization of electronic devices.

Alternatively, although a printed circuit board is arranged in a space that was conventionally wasted, or an attempt is made to reduce the wasted space as much as possible by using a flexible printed circuit board, a relatively small capacitance having a capacitance range of 10 μF or more is attempted. When it is necessary to mount an electrolytic capacitor having a large value on a printed circuit board, an occupied space having a height of at least about 10 mm to 4 mm is generated. This occupied space creates more useless space, and makes it difficult to mount electronic components efficiently.

An object of the present invention is to realize a plate-shaped solid electrolytic capacitor that improves the mounting efficiency of components in an electronic device.

[Means for solving the problem]

The present invention provides a solid electrolytic capacitor in which a dielectric layer, an electrolyte layer and a conductor layer are sequentially formed on both sides of a plate-like anode body, and a cathode terminal is provided through each conductor layer to form a capacitor element. A printed circuit board having a desired wiring pattern is bonded to both sides of the capacitor element by disposing a resin layer.

Further, in the method for manufacturing the solid electrolytic capacitor,
The capacitor element is characterized in that a plurality of anode bodies in which a dielectric layer, an electrolyte layer, and a conductor layer are sequentially formed on one surface are bonded to each other.

(Operation)

As shown in the drawings, in the present invention, a dielectric layer on the surface,
Anode body 1 in which electrolyte layer 2 and conductor layer 3 are sequentially formed
And a printed circuit board 6 provided with a desired wiring pattern 7 on both sides of a capacitor element 12 comprising a cathode terminal 4 arranged on the surface of the conductor layer 3 and an anode terminal 5 connected to the anode body 1. Therefore, the plate-shaped solid electrolytic capacitor itself can be used as a printed circuit board and other electronic components can be mounted.

When the electrolyte layer 2 is made of mechanically fragile polypyrrole, mechanical stress from the outside is reduced by the printed circuit boards 6 arranged on both sides of the capacitor element 12.
Never reach.

〔Example〕

Next, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a perspective view showing a solid electrolytic capacitor according to an embodiment of the present invention, and FIG. 2 is a partial cross-sectional perspective view showing a conceptual structure of an anode body according to the embodiment. FIG. 3 is a perspective view showing another embodiment of the present invention.

As shown in FIG. 2, the anode body 1 is formed of a plate-shaped body made of a valve metal such as aluminum, and includes a dielectric layer, an electrolyte layer 2 and a conductor layer 3 formed on the surface thereof.

That is, the surface of the anode body 1 is subjected to a selective etching process, for example, an electrolytic etching process to enlarge the surface, and a chemical conversion process is performed to form an oxide film. This oxide film is made of aluminum oxide obtained by oxidizing the surface layer of anode body 1, which is aluminum, and becomes a dielectric layer.

Then, an electrolyte layer 2 made of polypyrrole or the like is formed on the surface of the dielectric layer. The electrolyte layer 2 is formed by immersing the anode body 1 in a pyrrole solution containing an oxidizing agent, forming a pyrrole thin film by chemical polymerization, and further immersing in a pyrrole-dissolved electrolytic polymerization electrolytic solution and applying a voltage. As a result, a thickness of several μm to several tens μm is formed.

Further, a conductor layer 3 is screen-printed on the surface of the electrolyte layer 2. The conductor layer 3 may have either a multilayer structure composed of a carbon paste and a silver paste, or a single layer structure composed of a conductive adhesive containing a metal powder having good conductivity.

Then, the plurality of anode bodies 1 having the electrolyte layers 2 and the like formed on the front surface are joined via a conductive adhesive or the like applied to the back surfaces of the respective anode bodies 1 and, as shown in FIG. The anode body 1 is formed by sequentially forming the anode body 2 and the conductor layer 3. Further, a cathode terminal 4 made of a solderable metal such as copper is brought into close contact with both surfaces of the anode body 1, that is, the conductor layer 3 of the anode body 1 to form a capacitor element 12. The cathode terminal 4 may be joined to the conductor layer 3 via a conductive adhesive.

An anode terminal 5 for extracting an anode is connected to at least one surface of the anode body 1. This anode terminal 5
It is made of a solderable metal such as copper, and is joined to the anode body 1 by means such as ultrasonic welding or laser welding.

A printed circuit board 6 having a specific wiring pattern 7 formed on its surface is bonded to both sides of the capacitor element 12 via a heat-resistant resin layer 8. The printed circuit board 6 is, in this embodiment,
A glass epoxy having a thickness of 0.6 mm with a wiring pattern 7 formed on one side was used, and placed on and in close contact with both sides of a capacitor element 12 coated with epoxy resin on the surface. At this time, the anode terminal 5 and the cathode terminal 4 are protruded from the end of the printed circuit board 6 to the outside. In particular, the plurality of cathode terminals 4 are connected to each other at their protruding portions by means such as ultrasonic welding.

In such a solid electrolytic capacitor, the wiring pattern 7
The solid electrolyte layer 2 inside is protected by the printed board 6 formed on the surface thereof, and other electronic components can be mounted on the printed board 6.

Next, another embodiment of the present invention shown in FIG. 3 will be described. The anode body 1 is made of aluminum or the like as in the previous embodiment, and has an oxide film layer, an electrolyte layer 2 such as polypyrrole, and a conductor layer 3 selectively formed on the surface thereof. A plurality of anode bodies 1 are bonded together, and a cathode terminal 9 for extracting a cathode made of a solderable metal such as copper is arranged on the surface of the conductor layer 3 of the anode body 1 to form a capacitor element 13. . The cathode terminal 9 is shorter than the cathode terminal 4 in the previous embodiment.

On both surfaces of the capacitor element 13, a printed circuit board 10 made of glass epoxy or the like and having a wiring pattern 7 printed on the surface is disposed via a resin layer 8, and is fixed via an epoxy resin or the like. Further, a plurality of through holes 11 penetrating the anode body 1 and the cathode terminal 9 are provided together with the wiring pattern 7 of the printed board 10.

In this embodiment, the anode body 1 and the cathode terminal 9 are electrically connected to another electronic component or another electronic component mounted on the printed board 10 through the through hole 11 of the printed board 10. Therefore, unlike the above-described embodiment, the bipolar terminals 4 and 5 do not protrude to the outside, so that more efficient mounting on the electronic device becomes possible.

In this embodiment, the printed circuit board 10 has a plurality of through holes 11 penetrating the anode body 1 and the cathode terminal 9 respectively.
However, if necessary, a through-hole penetrating only one electrode, for example, only the cathode terminal 9 may be provided.

[Effects of the Invention] As described above, the present invention provides a solid electrolytic capacitor in which a dielectric layer, an electrolyte layer, and a conductor layer are sequentially formed on both surfaces of a plate-shaped anode body, and a cathode is formed through each conductor layer. A terminal is provided as a capacitor element, and a printed circuit board having a desired wiring pattern is bonded to both sides of the capacitor element by disposing a resin layer, so that even if the solid electrolyte has a weak mechanical strength, A highly reliable solid electrolytic capacitor protected by the printed circuit boards arranged on both sides can be obtained.

If a desired wiring pattern is formed on the printed circuit board in advance, other electronic components can be mounted, and high-density mounting is facilitated.

Further, in the method for manufacturing the solid electrolytic capacitor,
A capacitor element is formed by bonding a plurality of anode bodies each having a dielectric layer, an electrolyte layer, and a conductor layer sequentially formed on one surface. Therefore, by sequentially generating the electrolyte layers and the like on a single substrate, it becomes easy to uniformly generate the electrolyte layers and the like on the surface of the anode body to be bonded,
The manufacturing process is simplified and the reliability is improved.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a solid electrolytic capacitor according to an embodiment of the present invention, and FIG. 2 is a partial cross-sectional perspective view showing a conceptual structure of an anode body according to the embodiment. FIG. 3 is a perspective view showing another embodiment of the present invention. DESCRIPTION OF SYMBOLS 1 ... Anode body 2 ... Electrolyte layer 3 ... Conductor layer 4, 9 ... Cathode terminal 5 ... Anode terminal 6, 10 ... Printed circuit board 7 ... Wiring pattern 8 ... Resin layer 11 ... Through-hole 12,13 …… Capacitor element

Claims (2)

(57) [Claims] 1. A capacitor element in which a dielectric layer, an electrolyte layer and a conductor layer are sequentially formed on both sides of a plate-shaped anode body, and a cathode terminal is provided via each conductor layer to form a capacitor element. A solid electrolytic capacitor in which a printed circuit board having a desired wiring pattern on both sides is joined by disposing a resin layer. 2. The method for manufacturing a solid electrolytic capacitor according to claim 1, wherein the capacitor element is formed by laminating a plurality of anode bodies each having a dielectric layer, an electrolyte layer, and a conductor layer sequentially formed on the surface.