Electricity: electrothermally or thermally actuated switches – Electrothermally actuated switches – Fusible element actuated
Reexamination Certificate
1994-06-29
2001-07-10
Picard, Leo P. (Department: 2835)
Electricity: electrothermally or thermally actuated switches
Electrothermally actuated switches
Fusible element actuated
C337S232000, C337S248000, C337S251000, C361S275400, C361S306100, C361S309000
Reexamination Certificate
active
06259348
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a surface mounting type electronic component, such as a solid electrolytic capacitor, which incorporates a safety fuse wire such as a temperature fuse or an overcurrent fuse.
2. Description of the Related Art
Surface mounting type electronic components incorporating a safety fuse wire are known. A typical example is a fused surface mounting type solid electrolytic capacitor which is disclosed in Japanese Patent Application Laid-open No. 63(1988) -84010 or No. 2(1990)-105513 for example.
The solid electrolytic capacitor disclosed in either of the Japanese documents comprises a capacitor element which includes a capacitor chip and an anode wire projecting from the chip. The capacitor also includes a plate-like metal anode lead in direct electrical connection with the anode wire, and a plate-like metal cathode lead in electrical connection to the chip indirectly through a safety fuse wire. The capacitor element together with part of the respective leads is enclosed in a resin package, and the respective leads are bent outside the resin package for conveniently mounting to a surface of a circuit board.
According to the prior art arrangement, the provision of the anode and cathode leads inevitably increases the overall size and weight of the capacitor. Further, since the fuse wire need be attached to both of the capacitor chip and the cathode lead by wire bonding, the production cost of the capacitor increases due to the wire bonding operation which is relatively time- and labor-taking.
SUMMARY OF THE INVENTION
It is, therefore, an object of the present invention to provide a fused surface mounting type electronic component, in particular a solid electrolytic capacitor, which can eliminate or reduce the above described problems of the prior art.
The present invention also seeks to provide a method of conveniently making such an electronic component.
According to one aspect of the present invention, there is provided a surface mounting type electronic component comprising: an electronic element; a safety fuse wire having one end electrically connected to the electronic element; and a resin package enclosing the electronic element together with the fuse wire; wherein the other end of the fuse wire is exposed at a face of the resin package, said face of the resin package being formed with a layer-like terminal in electrical connection with said other end of the fuse wire.
Preferably, the fuse wire is partially enclosed in an elastic arc-extinguishing resin member. In case the electronic element is polar, the resin package may be externally formed with at least one indication, such as a groove, which is representative of the polarity of the electronic element.
According to one embodiment of the present invention, the electronic element has a face which is substantially parallel to said face of the resin package, said one end of the fuse wire being connected to said parallel face of the electronic element.
According to another embodiment of the present invention, the electronic element has a face which is substantially perpendicular to said face of the resin package, said one end of the fuse wire being connected to said perpendicular face of the electronic element. In this case, the fuse wire is bent for extending toward said face of the resin package.
Said other end of the fuse wire may made to project slightly from said face of the resin package. Alternatively, said other end of the fuse wire may be rendered flush with said face of the resin package.
Typically, the electronic element is a solid electrolytic capacitor element having a chip and an anode wire projecting from the chip. In this case, the resin package has another face at which a tip end of the anode wire is exposed, said another face of the resin package being formed with another layer-like terminal in electric connection with the tip end of the anode wire.
Similarly to the fuse wire, the tip end of the anode wire may project slightly from said another face of the resin package. Alternatively, the tip end of the anode wire may be flush with said another face of the resin package.
According to another aspect of the present invention, there is provided a method of making a surface mounting type electronic component comprising the steps of: attaching one end of a safety fuse wire to an electronic element; forming a resin package to enclose the electronic element together with the fuse wire so that the other end of the fuse wire is exposed at a face of the resin package; and forming a layer-like terminal on said face of the resin package in electrical connection with said other end of the fuse wire.
In one embodiment, said other end of the fuse wire projects from said face of the resin package to a greater degree immediately after forming the resin package but is subsequently cut to project to a smaller degree before forming the layer-like terminal.
In another embodiment, said other end of the fuse wire projects from said face of the resin package after forming the resin package but is subsequently cut to be flush with said face of the resin package before forming the layer-like terminal.
Other objects, features and advantages of the present invention will be fully understood from the following detailed description given with reference to the accompanying drawings.
REFERENCES:
patent: 3566003 (1971-02-01), Wislocky
patent: 4103416 (1978-08-01), Sakamoto
patent: 4538212 (1985-08-01), Montgomery
patent: 4695921 (1987-09-01), Robbins
patent: 4746784 (1988-05-01), Vermij
patent: 4926542 (1990-05-01), Bougger
patent: 5036434 (1991-07-01), Kobayashi
patent: 5057973 (1991-10-01), Gouvernelle et al.
patent: 5296833 (1994-03-01), Breen
patent: 0306809 (1989-03-01), None
patent: 0392087 (1990-10-01), None
patent: 0488130 (1992-06-01), None
patent: 2186752 (1987-08-01), None
patent: 63-84010 (1988-04-01), None
patent: 2105513 (1990-04-01), None
JP 4-3408 A. In: Patents Abstracts of Japan, E-1188, Apr. 10, 1992, vol. 16, No. 146.
Bednarek Michael D.
Picard Leo P.
Rohm & Co., Ltd.
Shaw Pittman
Vortman Anatoly
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