Electricity: electrical systems and devices – Electrolytic systems or devices – Solid electrolytic capacitor
Reexamination Certificate
2003-10-22
2004-08-10
Reichard, Dean A. (Department: 2831)
Electricity: electrical systems and devices
Electrolytic systems or devices
Solid electrolytic capacitor
C361S508000, C361S509000, C361S516000, C361S525000, C361S528000, C029S025030
Reexamination Certificate
active
06775126
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a solid electrolytic capacitor used in various electronic devices, and to a method of manufacturing the capacitor.
BACKGROUND OF THE INVENTION
FIG. 11
is a sectional view of a conventional solid electrolytic capacitor disclosed in Japanese Patent Laid-Open Publication No.2000-243665. One side or a middle core portion in a thickness direction of porous valve metal sheet
20
made of metal, such as aluminum and tantalum, is used as an electrode. Dielectric layer
21
is provided on a surface of a porous portion of the valve metal sheet
20
. Solid electrolyte layer
22
formed of a conductive polymer layer is provided on the dielectric layer
21
. Collector layer
23
is provided on the solid electrolyte layer
22
. An electrode layer made of metal is provided on the collector layer
23
.
When the solid electrolyte layer
22
is formed in this solid electrolytic capacitor, conductive polymer is formed at electrode lead-out portion
24
of the valve metal sheet
20
, thus causing a short-circuit or a current leaking. In order to prevent such trouble, the electrode lead-out portion
24
is separated from the solid electrolyte layer
22
with insulating separator
25
made of insulating resin provided at the electrode lead-out portion
24
.
The insulating separator
25
is generally formed by applying and hardening insulating resin, such as epoxy resin and silicone resin, or by affixing an insulating tape including polyamide as a base material. The solid electrolyte layer
22
becomes partially defective on the dielectric layer
21
close to the boundary between the dielectric layer
21
and the insulating separator
25
, and this may cause a short-circuiting or a current leaking.
When insulating resin is applied, the resin is sucked into the porous portions of the valve metal sheet
20
, and thus, the capacitor becomes unable to control its electrostatic capacity, losing its characteristics as a capacitor. Further, the application of insulating resin influences workability and mass-productivity in a manufacturing of the capacitor.
SUMMARY OF THE INVENTION
A solid electrolytic capacitor includes a valve metal sheet having a porous portion on a first surface of the sheet, a dielectric layer provided on the porous portion, a first insulating portion provided on an outer periphery of the dielectric layer, a solid electrolyte layer provided on the dielectric layer, a second insulating portion provided on an outer periphery of the solid electrolyte layer and on the first insulating portion, and a collector layer provided on the solid electrolyte layer.
The solid electrolytic capacitor causes less current leakage and assures a high withstand voltage.
REFERENCES:
patent: 5005107 (1991-04-01), Kobashi et al.
patent: 5189770 (1993-03-01), Waidhas et al.
patent: 6310765 (2001-10-01), Tanahashi et al.
patent: 6400554 (2002-06-01), Shiraishi et al.
patent: 6466430 (2002-10-01), Mido et al.
patent: 6473293 (2002-10-01), Shimada et al.
patent: 2000-243665 (2000-09-01), None
Fujii Tatsuo
Kimura Suzushi
Mido Yuji
Miki Katsumasa
Ha Nguyen T.
RatnerPrestia
Reichard Dean A.
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