JPH0448616A - Solid electrolytic capacitor and its manufacture - Google Patents

Abstract

PURPOSE:To improve the mounting efficiency of printed parts by producing dielectric layers, electrolytic layers, and conductor layers, in order on both sides of a plate-shaped anode body, and providing cathode terminals through each conductor layer so as to make it into a capacitor element, and then joining printed boards equipped with desired wiring patterns on both sides of the element through resin layers. CONSTITUTION:Printed boards 6, where specified wiring patterns 7 are formed on the surfaces, are joined through heat-resistant resin layers 8, to both sides of a capacitor element 12. For the printed boards 6, the ones, where wiring patterns 7 are formed on one side of each glass epoxy 0.6mm thick, are used, and those are joined fast to both sides of the capacitor element 12 where epoxy resin is applied on the surface. At this time, an anode terminal 5 and a cathode terminal 4 are projected out of the end of the printed board 6. Especially, for plural cathode terminals 4, those are conned with each other at the projections by the means such as supersonic welding, etc.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a solid electrolytic capacitor, and particularly to a plate-shaped solid electrolytic capacitor using an organic conductive compound.

[Background Art] In recent years, electronic components have been miniaturized due to demands for miniaturization of electronic devices and improvement of mounting efficiency on printed circuit boards.

Along with this, electrolytic capacitors are also becoming smaller.

However, in the case of an electrolytic capacitor, particularly an electrolytic capacitor that uses 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 miniaturize electrolytic capacitors, the limit is, for example, to reduce the height from the printed circuit board to about 10 mm or 4 mm, which is equivalent to the external dimensions of ceramic capacitors. It was extremely difficult to realize an electrolytic capacitor with a diameter of about 1 mm to 3 mm.

On the other hand, solid electrolytic capacitors that do not use electrolyte are made by forming a solid electrolyte layer made of manganese dioxide, etc. on an anode body made of tantalum or the like with an oxide film layer formed on the surface, and then carbon paste. and a conductive layer made of silver paste or the like. Since the electrolyte of such a solid electrolytic capacitor is solid, it is relatively easy to miniaturize the capacitor, and it is possible to miniaturize the capacitor.

[Problem to be solved by the invention]

However, the capacitance range of conventional solid electrolytic capacitors is limited to about 0.1 to 10 μF. In addition, although its impedance characteristics are superior to electrolytic capacitors using electrolyte, they are still insufficient compared to ceramic capacitors and the like, and if tantalum is used for the anode body, the cost will be high.

Furthermore, the mounting efficiency of electronic components in electronic devices is limited due to restrictions due to the external dimensions of the electronic components themselves. This prevents miniaturization.

Alternatively, although attempts have been made to reduce wasted space as much as possible by placing a printed circuit board in the space that was previously wasted or by using a flexible printed circuit board, there are still cases where the capacitance range is relatively large, with a capacitance range of 10 μF or more. When it is necessary to mount an electrolytic capacitor with a large value on a printed circuit board, an occupied space with a height dimension of at least IOma+ to 4+wm is created. This occupied space further creates wasted space, making it difficult to efficiently mount electronic components.

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

[Means to solve the problem]

This invention provides a solid electrolytic capacitor in which a dielectric layer, an electrolyte layer, and a conductive layer are sequentially formed on both sides of a plate-shaped anode body, and a cathode terminal is provided through each conductive layer to form a capacitor element. A feature of this capacitor element is that a printed circuit board with a desired wiring pattern is bonded to both sides of the capacitor element by disposing a resin layer thereon.

In addition, this solid electrolytic capacitor manufacturing method is characterized in that the capacitor element is formed by bonding together a plurality of anode bodies each having a dielectric layer, an electrolyte layer, and a conductor layer sequentially formed on one surface. .

[Function] As shown in the drawings, the present invention includes an anode body 1 on which a dielectric layer, an electrolyte layer 2, and a conductor layer 3 are sequentially formed on the surface;
A capacitor element 1 consisting of a cathode terminal 4 disposed on the surface of a conductor layer 3 and an anode terminal 5 connected to an anode body 1
Since the printed circuit board 6 having the desired wiring pattern 7 is arranged on both sides of the capacitor 2, the plate-shaped solid electrolytic capacitor itself can be used as a printed circuit board and other electronic components can be mounted thereon.

In addition, when the electrolyte layer 2 is made of mechanically fragile polypyrrole, external mechanical stress is applied to the electrolyte layer by the printed circuit board 6 disposed on both sides of the capacitor element 12.
It never reaches the point.

〔Example〕

Next, embodiments of the 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 partially sectional perspective view showing the conceptual structure of an anode body according to the embodiment.

FIG. 3 is a perspective view showing another embodiment of the invention.

As shown in FIG. 2, the anode body 1 consists 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 10 is subjected to a selective engraving treatment, such as an electrolytic etching treatment, to enlarge the surface, and a chemical conversion treatment is performed to form an oxide film. This oxide film is made of aluminum oxide obtained by oxidizing the surface layer of the 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 this dielectric layer. The electrolyte layer 2 is formed by immersing the anode body 1 in a pyrrole solution containing an oxidizing agent to form a pyrrole thin film through chemical polymerization, and then immersing it in an electrolyte solution for electrolytic polymerization in which pyrrole is dissolved and applying a voltage. Then, the film is formed to have a thickness of several μm to several + μm.

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

Then, a plurality of anode bodies 1 with electrolyte layers 2 etc. formed on their surfaces are joined together via a conductive adhesive applied to the back surfaces of each other, and as shown in FIG. The anode body 1 includes a conductor layer 2, a conductor layer 3, and the like formed in this order. Furthermore, both sides of this anode body 1, that is, the conductor layer 3 of the anode body 1
Next, the capacitor element 12 is formed by closely contacting the cathode terminal 4 made of a metal such as copper that can be soldered. Note that the cathode terminal 4 may be bonded to the conductor layer 3 via a conductive adhesive.

Furthermore, an anode terminal 5 for drawing out the anode is connected to at least one surface of the anode body 1. This anode terminal 5 is made of a metal such as copper that can be soldered, 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 surfaces of the capacitor element 120 via a heat-resistant resin layer 8 . In this embodiment, the printed circuit board 6 is
A piece of glass epoxy with a wiring pattern 7 formed on one side having a thickness of 0.6 mm was used, and the wiring pattern 7 was placed on both sides of a capacitor element 12 whose surface was coated with an epoxy resin, and was brought into close contact with the glass epoxy.

At this time, the anode terminal 5 and the cathode terminal 4 are made to protrude from the end of the printed circuit board 6 to the outside. Especially multiple 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 internal solid electrolyte layer 2 is protected by the printed circuit board 6 on which the wiring pattern 7 is formed, and other electronic components can be mounted on the printed circuit board 6. .

Next, another embodiment of the 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 an oxide film layer, an electrolyte layer 2 such as polypyrrole, and a conductor layer 3 are selectively formed on the surface of the anode body 1 in this order. A plurality of these anode bodies 1 are pasted together, and a cathode terminal 9 for drawing out the cathode made of a metal that can be soldered such as copper is arranged on the surface of the conductive layer 3 of the anode body 1, thereby forming a capacitor element 13. do. The cathode terminal 9 is formed shorter than the cathode terminal 4 in the previous embodiment.

On both sides of the capacitor element 13, a printed circuit board 10 made of glass epoxy or the like and having a wiring board 7 printed on its surface is disposed with a resin layer 8 interposed therebetween and fixed thereto via an epoxy resin or the like. It is provided with a plurality of through holes 11 that pass through the anode body 1 and the cathode terminal 9, as well as the wiring pattern 7 of the printed circuit board 10.

In this embodiment, the anode body 1 and the cathode terminal 9 are electrically connected to other electronic components or other electronic components mounted on the printed circuit board 10 through the through holes 11 of the printed circuit board 10. Ru. Therefore, the polar terminals 4 and 5 do not protrude to the outside as in the above-mentioned embodiments, and more efficient attachment to electronic equipment is possible.

In this embodiment, the printed circuit board 1o has a plurality of through holes 1 passing through the anode body l and the cathode terminal 9, respectively.
1 is provided, but if necessary, a through hole may be provided that penetrates only one electrode, that is, for example, the cathode terminal 9.

〔Effect 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 sides of a plate-shaped anode body, and a cathode terminal is provided through each conductor layer. A printed circuit board with the desired wiring tabs is attached to both sides of the capacitor element with a resin layer, so even solid electrolytes with weak mechanical strength can be placed on both sides. A solid electrolytic capacitor protected by a printed circuit board and having high reliability can be obtained.

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

Furthermore, in this method for manufacturing a solid electrolytic capacitor, a capacitor element is formed by bonding together 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 electrolyte layers on a single substrate, it becomes easy to uniformly generate electrolyte layers on each surface of the anode body to be bonded, which simplifies the manufacturing process and improves reliability. do.

[Brief explanation of 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 partially sectional perspective view showing the conceptual structure of an anode body according to the embodiment. FIG. 3 is a perspective view showing another embodiment of the invention. l... Anode body 2... Electrolyte layer 3... Conductor layer 4.9... Cathode terminal 5... Anode terminal Figure 2 6, 10... Printed board 7... Wiring pattern 8...Resin layer II...Through holes 12, 13...Capacitor element

Claims (2)

[Claims] (1) 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 through each conductor layer to form a capacitor element. , a printed circuit board with the desired wiring pattern,
A solid electrolytic capacitor bonded with a resin layer. (2) The method for manufacturing a solid electrolytic capacitor according to claim 1, wherein the capacitor element is formed by bonding together a plurality of anode bodies each having a dielectric layer, an electrolyte layer, and a conductor layer sequentially formed on the surface thereof.