Nec Corporation

Hiromichi Taniguchi

Satoshi Arai

Toshihiko Nishiyama

Takashi Fukaumi

Atsushi Kobayashi

Masashi Ohi

Atushi Kobayashi

Koji Sakata

Yoshihiko Saiki

Maki Minamoto

A chip-formed solid electrolytic capacitor having a structure wherein a projecting anode lead is not provided for an anode member. The solid electrolytic capacitor is fabricated by the following manner: First, an electrically insulating resin such as a fluororesin is impregnated into an end face of a porous electrode member to form an insulating resin impregnated portion, and an electrode lead member is bonded to the anode member at the insulating resin impregnated portion. An anodic oxidation film, a solid electrolyte layer and a cathode layer successively are formed on the anode member. Then, an electrically insulating outer package is applied so that the cathode layer on a face of the anode member opposing to the face on which the electrode lead member is mounted is exposed. After removing the electrode lead member, an anode outer electrode layer is formed on the insulating resin impregnated portion, and a cathode outer electrode layer which electrically connects to the cathode layer is formed on the end face of the anode member opposing to the anode outer electrode layer.

Method of forming chip-formed solid electrolytic capacitor without an

The solid electrolytic capacitor disclosed has a conducting polymer as a solid electrolyte and an antioxidant contained substantially only in a layer disposed in the neighborhood of a surface of the conducting polymer. The antioxidant serves to block the progress of oxidation of organic materials. A capacitor element with conducting polymer not containing the antioxidant is first prepared and this capacitor element is then dipped in a solution containing the antioxidant. Thus, the antioxidant at high concentration is caused to be introduced into the conducting polymer so as to be contained substantially only in a layer disposed in the neighborhood of the surface of the conducting polymer. Since the antioxidant can be introduced by merely dipping the capacitor element in the antioxidant solution, the method can be applied widely to capacitors irrespective of the process of conducting polymer formation. The antioxidant concentration inside the conducting polymer is substantially zero so that the conductivity thereof is not affected.

Solid electrolytic capacitor with conductive polymer as solid

Chip-formed solid electrolytic capacitor without an anode lead

In a solid electrolytic capacitor which employs a conducting polymer as the solid electrolyte, a first solid electrolytic layer (3) consisting of a sole conducting polymer is formed by chemical polymerization on an oxide film (2) formed on the surface of an anode body (1). Next, a second solid electrolytic layer (4) consisting of a conducting polymer containing fine powder, obtained by chemical polymerization using a solution in which fine powder is dispersed in a reaction solution for chemical polymerization, is formed on the first solid electrolytic layer (3). The fine powder is harder than the conducting polymer. With this arrangement, it is possible to prevent the application of a stress to the oxide film (2) by the solid electrolytic layer (4) consisting of a conducting polymer containing fine powder even if there is generated a stress at the time of curing of a molded resin (8).

Solid electrolytic capacitor having two solid electrolyte layers and

The present invention provides a solid electrolytic capacitor comprising a metal having a dielectric oxide film formed thereon, a conductive polymer compound layer formed on said dielectric oxide film, a conductive paste layer formed on said conductive polymer compound layer, a molded resin sheathing having all of the above members buried therein, and a pair of electrodes connected to said metal and said conductive paste layer, respectively, in which capacitor an antioxidant is scattered, in the form of particles, in at least one of said conductive polymer compound layer, said conductive paste layer and the interface between the conductive polymer compound layer and the conductive paste layer; and a process for production of said capacitor.

Solid electrolytic capacitor and process for production thereof

A chip type solid electrolyte capacitor is given a three-terminal structure, with cathode terminals at either end and an anode lead embedded in an anode body at the center of the device structure. This eliminates the possibility of device breakdown or short circuit when a chip-type solid electrolyte capacitor with rectifying characteristics is inadvertently mounted the wrong way on a circuit board, and assures a small device size.

Chip type solid electrolyte capacitor

The invention relates to a chip-type solid elelctrolytic capacitor which uses a capacitor element having an anode lead protruding from one end face of an anode body of a valve metal. The capacitor element is covered by an insulating resin cover layer except a cathode end face and the protruding part of the anode lead. A cathode terminal is formed on the cathode end face and the resin cover layer in an area near the cathode end face, and an anode terminal is formed on the resin cover layer so as to make contact with the protruding anode lead. The anode terminal is made up of a conductive layer which is formed on the resin cover layer only in a limited area so as not to make contact with the anode lead and has a microscopically rough surface, a plating layer which is formed on the conductive layer and the resin cover layer in the area over the aforementioned end face of the anode body and covers the protruding anode lead and a solder layer formed on the plating layer. In the anode terminal the rough surface of the conductive layer enhances the adhesion of the overlaid plating layer, and the separation of the conductive layer from the anode lead eliminates the problem about different thermal expansion coefficients of the conductive layer and the anode lead. Therefore, when the chip-type capacitor is mounted on a printed circuit board the bonding strength is enhanced.

Chip-type solid electrolytic capacitor

According to this invention, a chip type solid electrolytic capacitor includes a capacitor element, an insulating sheathing resin layer, two anode terminals, and a cathode terminal. The capacitor element is obtained by sequentially forming an oxide film, a solid electrolytic layer, and a cathode conductive layer on an anode body consisting of a valve metal in which anode leads are extracted from two opposite end faces. The insulating sheathing resin layer is coated on an entire outer surface except for both anode lead extraction end faces and a predetermined portion of one surface. The two anode terminals are formed on both the anode lead extraction end faces and peripheral portions thereof. The cathode terminal is formed on the cathode conductive layer exposed from said insulating sheathing resin layer.

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Tokyo, Japan

Hiromichi Taniguchi