Metal working – Method of mechanical manufacture – Assembling or joining
Patent
1982-06-11
1984-11-20
Hearn, Brian E.
Metal working
Method of mechanical manufacture
Assembling or joining
H01G 924
Patent
active
044830629
DESCRIPTION:
BRIEF SUMMARY
FIELD OF TECHNOLOGY
This invention relates to a method for manufacturing a solid electrolyte condenser encapsulated with an insulating resin.
BACKGROUND ART
Hitherto, this type of solid electrolyte condenser was formed by preparing a condenser element formed by sequentially depositing a layer of semiconductor metal oxide such as manganese dioxide, a cathode layer made of carbon and a cathode current collecting layer made of silver paint, on an anode of a sintered body of valve metal such as tantalum having an anode lead-out line, which is made of a valve metal such as tantalum, and also, having a surface thereof formed with a dielectric oxidizing film, and then encapsulating this condenser element with an insulating resin. From this condenser body extend an anode terminal connected to the anode lead-out line, and a cathode terminal connected to the cathode current collecting layer.
In general, a chip component such as the solid electrolyte condenser is soldered to a land on a circuit board by passing, after it has been directly placed on the circuit board, through a furnace heated to 200.degree. to 270.degree. C. or fixed on the circuit board by the use of a bonding agent and soldered to the land on the circuit board by dipping the whole of the chip component in a solder bath with the chip component oriented downwards, and for this reason the chip component tends to be heated to 200.degree. to 270.degree. C. and, therefore, must have an appropriate heat resistance.
On the other hand, in the solid electrolyte condenser, soldering is used in connecting the condenser element with the cathode terminal because of its high workability and inexpensiveness, but in view of the fact that the silver paint is used to form the cathode current collecting layer tends to erode more and more as the temperature increases, any solder having a melting point higher than 270.degree. C. cannot be used and, therefore, a solder of about 183.degree. to 270.degree. C. is used.
In addition, in this type of solid electrolyte condenser, referring to FIG. 1(a), the cathode terminal is connected by dipping a condenser element 1 with the conventional cathode current collecting layer formed thereon into a flux or rosin-isopropyl alcohol type to apply a flux 2 thereto (Even though the condenser element is partially dipped into the flux, the flux adheres to the whole of the cathode current collecting layer by capillary action), then dipping it into a solder bath of about 200.degree. to 230.degree. C. to form a solder layer 3 on the cathode current collecting layer as shown in FIG. 1 (b), and finally dipping it again into the solder bath while the cathode terminal is connected to the solder layer 3.
However, where this type of solder is used, in view of the facts that the temperature at which soldering to the circuit board is performed is as high as 200.degree. to 270.degree. C. and that the whole is dipped into the solder bath, the solder inside tends to fuse and thermally expand enough to break a weak area of an encapsulating resin or to spatter outwards, resulting in breakage, resin cracking, a defect in appearance and other defects.
SUMMARY OF THE INVENTION
Accordingly, this invention is intended to provide a method for manufacturing a solid electrolyte condenser wherein the cathode terminal is connected by forming a solder layer partially on the cathode current collecting layer to be connected with the cathode terminal and then remelting and solidifying the solder layer while said cathode terminal is held in contact with the solder layer, which method is free from any possible spattering of solder and is effective to produce the condenser free from any breakage or defect in appearance.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGS. 1(a) and (b) are perspective views showing part of the conventional method for manufacturing a solid electrolyte condenser;
FIGS. 2, 3, 4 and 5 are perspective views showing steps of a method for manufacturing a chip-like solid electrolyte condenser according to one embodiment of this invention;
FIGS. 6(a)
REFERENCES:
patent: 3855505 (1974-12-01), Karlik, Jr. et al.
Conwicke, J. A. et al., "Compositions for the Selective Placement of Solders and Brazes", in IEEE International Convention Digest, 1971, pp. 446-447.
Hearn Brian E.
Matsushita Electric - Industrial Co., Ltd.
Schiavelli Alan E.
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