JPS63935B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a chip type solid electrolytic capacitor and a manufacturing method, and particularly to an electrode terminal of a chip type solid electrolytic capacitor.

A conventional chip type solid electrolytic capacitor has a structure disclosed in US Pat. No. 3,855,505. For example, as shown in FIGS. 1a and 1b, a metal cathode terminal 2 with a channel-shaped cross section is connected and fixed to the cathode portion of a capacitor element 1 via a conductive adhesive 3 for the purpose of determining the outer surface and polarity of the capacitor element 1. An insulating resin 4 is applied to one surface of the cathode terminal 2, and then a metal anode terminal 5, which has a channel-shaped cross section with the same external shape as the cathode terminal 2 and has a hole in the center of the bottom, is attached to the end of the capacitor element 1. After fitting the anode internal lead wire 6 and the hole into the hole and covering the anode terminal 5 and the anode internal lead wire 6 by welding, the gap between the anode terminal 5 and the capacitor element 1 is again filled and coated with insulating resin 4. Manufactured.

In this case, since the product is very small, when connecting the cathode terminal 2 via the conductive adhesive 3, it is necessary to eliminate the inclination of the cathode terminal 2 and the exposure of the conductive adhesive 3, and to connect and fix the connection with high positional accuracy. This required a huge amount of man-hours.

Furthermore, since the insulating resin 4 is applied to one surface of the cathode terminal 2 to indicate the polarity, the mounting surface is limited to only one surface, and the exterior is painted with the insulating resin 4 by brush painting or by dipping. Because of this, the accuracy of the external dimensions was low.

In order to eliminate these conventional drawbacks, U.S. Patent No.
An improved structure disclosed in No. 3588627 has appeared. In this improved structure, as shown in FIGS. 2a and 2b, metal cap-shaped terminals are used for both the anode and cathode terminals 5, 2, and the exterior is made of a heat-shrinkable tube 7. Compared to the conventional structure shown in FIGS. 1 a and b, the improved structure shown in FIGS. 2 a and b can connect and fix the cathode terminal 2 without exposing the conductive adhesive 3, and the However, since the heat-shrinkable tube 7 is used for the exterior, the accuracy of the external dimensions is low due to the influence of the finished dimensions of the capacitor element 1 and the unevenness of the surface.

In both of the above structures, the positive and negative terminals 5 and 2 have the same shape, so the only way to determine the polarity using a parts feeder, etc. and automatically mount it on a wiring board such as a printed circuit board is to use magnetic polarity determination method. .
For this reason, it was necessary to selectively use magnetic and non-magnetic materials for both the positive and negative terminals 5 and 2.

Furthermore, for the exterior parts of the conventional structures shown in Figures 1a and b, the insulating resin 4 is applied by brush painting or by dipping, and for the improved structures shown in Figures 2a and b, the insulating resin 4 is coated with a heat shrink tube 7. Because of this, there are problems such as the surface of the exterior part being extremely uneven, the accuracy of external dimensions being low, and the exterior surface being rounded as a whole. Therefore, products with both structures do not display polarity, rated capacity, rated voltage, etc. by stamping or the like. Therefore, a huge amount of man-hours are required to confirm the product name before and after mounting on a wiring board, and to confirm and replace defective parts after mounting. In addition, since the exterior surface and the positive and negative terminals 5 and 2 are not flat, the recently used temporary mounting method of temporarily fixing the components to the wiring board using adhesive etc. is used as a mounting method on the wiring board. There were drawbacks such as the inability to

SUMMARY OF THE INVENTION An object of the present invention is to eliminate these drawbacks and provide a chip-type solid electrolytic capacitor whose polarity can be easily determined and whose external dimensions are highly accurate.

According to the present invention, a part of the anode part and a part of the cathode part of the capacitor element are each exposed, and the exterior part is made of insulating resin and has a desired shape with high dimensional accuracy. A chip-type solid electrolytic capacitor and a method for producing the same are obtained, in which cap-shaped conductive terminals are connected and fixed to the exposed cathode portion so as to form the same plane as the insulating resin surface, respectively, and a method for manufacturing the same. .

Hereinafter, a chip type solid electrolytic capacitor according to the present invention will be explained with reference to the drawings.

First, the capacitor element 1 is made by implanting an anode internal lead wire 6 made of a metal having a valve action into a metal powder having a valve action, such as tantalum, niobium, or aluminum, and forming it into a certain external shape, as has been known in the past. Then, this is vacuum sintered at a temperature of 1600°C to 2100°C, a dielectric oxide film is formed on the surface of this sintered body by anodic oxidation, and a manganese dioxide layer, which is an electrolyte, is added to the surface using a manganese nitrate solution. It is formed by thermally decomposing manganese dioxide, and a carbon layer, a silver paint layer, etc. are formed on this manganese dioxide.

The capacitor element 1 constructed in this manner is set in the molding die 8 shown in FIGS. 3a and 3b as shown in FIG. A resin molded product in which the cathode side end 1a of the capacitor element 1 and the tip of the anode internal lead wire 6 are exposed, and the molded insulating resin 4 has stepped portions 4a and 4b at both ends of the upper and lower sides. is obtained.

A solderable metal anode terminal 5 having a channel-shaped cross section and a hole through which the anode internal lead wire 6 passes through at the center of the bottom is fitted into the stepped portion 4a of the resin molded product thus obtained. The internal lead wire 6 and the anode terminal 5 are connected and fixed by welding.

Furthermore, a conductive adhesive 3 is applied to the cathode side end 1a of the capacitor element 1 exposed from the insulating resin 4, and a cathode terminal 2 made of a square metal case that can be soldered is fitted into the stepped part 4b to make the conductive By curing the adhesive 3 and connecting and fixing the capacitor element 1 and the cathode terminal 2, a chip-type solid electrolytic capacitor having the structure shown in FIGS. 5a and 5b is obtained.

In the above, a stepped portion may be provided so that the surfaces of the insulating resin 4 and both anode and cathode terminals 5 and 2 are all on the same plane, but for the purpose of automatic alignment (polarity determination) by a parts feeder etc. , b, the anode terminal 5 and the 4 surfaces of the insulating resin 4 are all flat, and the cathode terminal 2 is connected to the stepped portion 4b of the insulating resin 4.
It is also possible to make only the two surfaces having a flat surface and the other two surfaces protrude from the four insulating resin surfaces by the thickness of the cathode terminal 2 (0.10 to 0.30 mm).

As described above, the chip type solid electrolytic capacitor of the present invention has (a) higher external dimensional accuracy than the conventional chip type solid electrolytic capacitors having the structures shown in FIGS. 1a, b and 2 a, b. Both terminals can be easily connected and fixed with high positional accuracy.

(b) Since the positive and negative terminals have different external shapes, it is easy to visually determine the polarity before and after mounting on the wiring board.
In addition, by using the portion of the cathode terminal that protrudes from the insulating resin surface, alignment (polarity determination) using a parts feeder or the like is possible without changing the materials of both the positive and cathode terminals.

(c) By using the same flat surfaces of both the positive and negative terminal surfaces and the insulating resin surface, it is possible to use a temporary attachment method to the wiring board using adhesive or the like.

(d) The insulating resin surface is flat, and this flat surface can be used to display polarity, rated capacity, rated voltage, etc. by stamping, etc., allowing confirmation of product name and identification of defective parts before and after mounting. Confirmation exchange is easy.

Since it has the following advantages, it is highly effective industrially.

[Brief explanation of the drawing]

FIGS. 1A and 1B and 2A and 2B are a perspective view and a sectional view, respectively, of a conventional chip-type solid electrolytic capacitor. Figure 3 shows the main parts of the mold used in the exterior packaging process of the present invention, a, b are perspective views and sectional views, c
is a cross-sectional view of the capacitor element set in the mold. FIGS. 4a, b, and c are sectional views and perspective views after resin molding according to the present invention. Figures 5a and 5b are a perspective view and a sectional view of a finished product according to the present invention. DESCRIPTION OF SYMBOLS 1... Capacitor element, 1a... Cathode side end of capacitor element, 2... Cathode terminal, 3... Conductive adhesive,
4... Insulating resin, 4a, 4b... Step portion, 5... Anode terminal, 6... Anode internal lead wire, 7... Heat shrink tube, 8... Molding mold.

Claims (1)

[Scope of Claims] 1. A conductive terminal having a channel-shaped cross section on the anode exposed side of a capacitor element having an insulating resin exterior, and a cap-shaped conductive terminal on the cathode exposed side, respectively, on the insulating resin surface. A chip-type solid electrolytic capacitor characterized by being connected and fixed so as to form the same plane as the chip. 2. The chip-type solid electrolytic capacitor according to claim 1, wherein two opposing side surfaces of the cap-shaped conductive terminal protrude beyond the insulating resin surface. 3 A process of exposing a part of the anode part and a part of the cathode part of the capacitor element and applying an exterior with a desired shape with high dimensional accuracy using insulating resin, and adding a cross-sectional channel-shaped conductive terminal on the side of the exposed anode part and exposing the cathode part. 1. A method for manufacturing a chip-type solid electrolytic capacitor, comprising the step of connecting and fixing cap-shaped conductive terminals on the side of the cap so as to form the same plane as the insulating resin surface.