Aluminum Or Tantalum Patents (Class 361/529)
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Patent number: 6370017Abstract: An electrode for a capacitor having an electrode charge eliminator and an electrode body which is contacted with the electrode charge eliminator and on whose surface a dielectric layer is formed. An intermediate layer blocking the exchange of matter between the dielectric layer and the electrode body is formed between the electrode body and the dielectric layer. The diffusion of oxygen from the dielectric layer into the electrode body is prevented with the aid of the intermediate layer, in particular, so that the electrode exhibits a higher long-time stability.Type: GrantFiled: November 28, 2000Date of Patent: April 9, 2002Assignee: Epcos AGInventors: Melanie Stenzel, Holger Zillgen, Janos Giber
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Patent number: 6351371Abstract: An anodic electrode for an electrolytic capacitor having high capacitance with low-resistance properties at high frequencies and capable of carrying large current, and a process of producing the same. Such an anodic electrode for electrolytic capacitor includes a porous body having micropores to be formed with a dielectric layer therein and to be filled with electrolyte therein, wherein the porous body includes a laminate of a plurality of sinter layers having the micropores formed from valve metal particles. The laminate includes multilaminarly smaller micropore-size regions and larger micropore-size regions to form electric conductive passages between the small micropore-size regions and side surfaces of the porous body to reduce resistance of the capacitor and also increase capacitance by utilizing the smaller micropores-size regions for capacitor effectively.Type: GrantFiled: April 14, 2000Date of Patent: February 26, 2002Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Tsunenori Yoshida, Kenji Hoshino, Masakazu Tanahashi, Yoshihiro Higuchi
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Patent number: 6351370Abstract: A solid electrolytic capacitor includes a valve acting metal having microfine pores, a dielectric film formed on a surface of the valve acting metal, and a solid electrolyte layer provided on the dielectric film, in which at least a portion of the solid electrolyte layer is of a lamellar structure. In particular, a solid electrolytic capacitor includes an electrically conducting polymer having a specified condensed ring structure containing (1) a solid electrolyte layer containing a sulfoquinone anion having a sulfo anion group and a quinone structure and other anion, and (2) a solid electrolyte layer containing an anthracenesulfonate ion and other anion.Type: GrantFiled: January 20, 1999Date of Patent: February 26, 2002Assignee: Showa Denko K.K.Inventors: Hiroshi Konuma, Koro Shirane, Ryuji Monden, Atsushi Sakai, Yuji Furuta, Katsuhiko Yamazaki, Toru Sawaguchi, Hideko Ohata, Yoshiaki Ikenoue
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Patent number: 6334945Abstract: A process for isolating flaw sites in the dielectric of solid electrolytic capacitor comprising immersing a conductive polymer impregnated capacitor in an electrolyte solution, and then alternately subjecting the conductive polymer impregnated capacitor to a high voltage and a low voltage; wherein the high voltage is between about 10 volts and 50 volts, and the low voltage is between about 0 volts and the voltage corresponding to 90% of the anodization voltage for pellets anodized at less than 20 volts, or the voltage at which the current drops to 50% of the peak voltage current for pellets anodized at voltages greater than or equal to 20 volts. The period of time at or above the anodization voltage is relatively short to prevent damaging the dielectric film.Type: GrantFiled: September 7, 2000Date of Patent: January 1, 2002Assignee: Kemet Electronics CorporationInventors: Philip Michael Lessner, Randolph Stephen Hahn, Brian John Melody, Erik Karlsen Reed, John Tony Kinard
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Patent number: 6324051Abstract: A solid electrolytic capacitor includes a capacitor element having an anode of a valve action metal, an oxide film layer formed on the surface of the anode, a solid electrolytic layer formed on the oxide film layer and a cathode electrically connected to the solid electrolytic layer, and also a packaging resin formed to cover the capacitor element. An intermediate layer to relieve stress is arranged in at least one part of the interface between the cathode and the packaging resin. The intermediate layer is deformed and/or peels to relieve stress caused by heat applied while mounting the capacitor element on a substrate.Type: GrantFiled: October 26, 2000Date of Patent: November 27, 2001Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Emiko Igaki, Masakazu Tanahashi, Chiharu Hayashi, Yoshiki Hashimoto
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Patent number: 6322912Abstract: Methods to at least partially reduce valve metal oxides are described wherein the process includes heat treating the valve metal oxide in the presence of a getter material, in an atmosphere which permits the transfer of oxygen atoms from the starting valve metal oxide to the getter material, and for a sufficient time and at a sufficient temperature to form an oxygen reduced valve metal oxide. Valve metal oxides and/or suboxides thereof are also described as well as capacitors containing anodes made from the valve metal oxides and suboxides thereof.Type: GrantFiled: September 15, 1999Date of Patent: November 27, 2001Assignee: Cabot CorporationInventor: James A. Fife
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Patent number: 6238810Abstract: A surface active, viscosity modifying agent is used to promote additional tunnel initiation during the etching of high purity cubicity anode foil, preferably aluminum anode foil, to render it suitable for use in electrolytic capacitors. The anode foil is etched in the electrolyte bath composition by passing a charge rough the bath, resulting in an anode foil having a higher capacitance than foils etched using known methods or etching compositions. The etched anode foil is suitable for use in an electrolytic capacitor.Type: GrantFiled: April 7, 1999Date of Patent: May 29, 2001Assignee: Pacesetter, Inc.Inventors: Thomas Flavian Strange, Ralph Jason Hemphill
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Patent number: 6238444Abstract: The tantalum chip capacitor of the present invention includes a anode terminal which is substantially flat. The tantalum wire which extends from the tantalum pellet through the insulating material terminates substantially flush with the insulating material, allowing the termination materials to be applied over a substantially flat surface. The tantalum chip capacitors of the present invention are created by methods which include the step of grinding the anode end of the capacitor so that the tantalum wire is flush with the insulating material. Conductive materials can then be applied to the anode end of the capacitor creating a substantially flat anode terminal.Type: GrantFiled: October 7, 1998Date of Patent: May 29, 2001Assignee: Vishay Sprague, Inc.Inventor: John Yates Cadwallader
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Patent number: 6214060Abstract: A process for making a capacitor element for a solid electrolytic capacitor is provided. The process includes the steps of compacting valve metal powder into a porous chip so that an anode wire projects from the porous chip via an end surface, fixing an anode plate to the anode wire, applying a synthetic resin material on the anode wire between the anode plate and the end surface of the porous chip, and forming a dielectric layer, a solid electrolytic layer and a cathode terminal layer on the porous chip.Type: GrantFiled: December 8, 1998Date of Patent: April 10, 2001Assignee: Rohm Co., Ltd.Inventor: Chojiro Kuriyama
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Patent number: 6212065Abstract: A capacitor includes a porous pellet formed from compressed conductive particles. The pellet has a lead receiving external surface. The conductive particles at the lead receiving surface are fused together to create a fused layer on the external surface of the pellet. A lead wire has one of its ends welded to the fused layer on the surface of the pellet. The fused layer is formed by exposing it to high temperatures, preferably by use of a laser beam.Type: GrantFiled: April 1, 1999Date of Patent: April 3, 2001Assignee: Vishay Sprague, Inc.Inventors: Yuri L. Pozdeev-Freeman, Boris Levi, Semion Akselrod
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Patent number: 6206937Abstract: A solid electrolytic capacitor comprising comprises a pair of electrodes, and a dielectric film provided between the paired electrodes wherein at least one of the paired electrodes comprising a first conductive polymer layer which is made of a polymer of a member selected from the group consisting of pyrrole and derivatives thereof, the first conductive polymer layer being doped with a mixed dopant of a polyvalent anion and a monovalent anion consisting of a sulfonate ion dissociated from an anionic surface active agent. The conductive polymer layer may have a double-layered or a multi-layered structure wherein a second and/or third conductive polymer layer is made of a doped polymer of a thiophene derivative. A method for making the capacitors are also described.Type: GrantFiled: September 4, 1998Date of Patent: March 27, 2001Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Yasuo Kudoh, Kenji Akami, Toshikuni Kojima, Yasue Matsuya, Hiroshi Shimada, Chiharu Hayashi
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Patent number: 6185090Abstract: Doped tantalum and niobium pellets with nitrogen is described wherein the resulting pellets are substantially free of nitride precipitate on their outer surfaces. The tantalum and niobium pellets are formed by heating the pellets to a temperature of from about 600-1400° C. in a nitrogen gas atmosphere and then in a vacuum which causes nitrogen contacting a pellet to diffuse into the inner portion of the pellet instead of forming a precipitate. The resulting pellets have improved DCL stability and reliability in comparison to prior art nitrogen-doped tantalum and niobium pellets.Type: GrantFiled: September 3, 1998Date of Patent: February 6, 2001Assignee: Vishay Sprague, Inc.Inventor: Yuri L. Pozdeev-Freeman
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Patent number: 6185091Abstract: Anodic valve metal foils, roughened and provided with dielectric layers, and collector metal foils (metal foils for collector) are laminated alternately to cross with cathodic electroconductive polymer layers therebetween. Anodic terminals and cathodic terminals are connected with the respective ends of the metal foils. For the anodic valve metal foils, an aluminum foil whose internal is an unroughened bulk metal layer is used. The collector metal foil is selected from the group consisting of an Al foil similar to the anodic valve metal foil, an Ni foil, a Cu foil, and an aluminum foil including carbon. As a result, a four-terminal capacitor to provide high capacitance, low impedance, high current-carrying capacity and less heat generation, as well as low ESR and low ESL, is obtained.Type: GrantFiled: February 8, 1999Date of Patent: February 6, 2001Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Masakazu Tanahashi, Mikinari Shimada, Emiko Igaki
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Patent number: 6168706Abstract: Aluminum anode foil is etched using a process of treating the foil in an electrolyte bath composition comprising aluminum chloride hexahydrate, hydrochloric acid, sulfuric acid and perchloric acid or perchlorate. The anode foil is etched in the electrolyte bath composition by passing a direct current (DC) through the bath, resulting in an aluminum anode foil having a higher capacitance and/or metal strength than using known methods or etching compositions. The etched anode foil is suitable for use in an electrolytic capacitor.Type: GrantFiled: December 11, 1998Date of Patent: January 2, 2001Assignee: Pacesetter, Inc.Inventors: Ralph Jason Hemphill, Thomas Flavian Strange
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Patent number: 6165623Abstract: A flaked niobium powder is disclosed as well as electrolytic capacitors formed from the flaked niobium powders. Niobium powders having a BET surface area of at least about 0.50 m.sup.2 /g are also disclosed and capacitors made therefrom, as well as niobium powders doped with an oxygen content of at least 2,000 ppm. Methods to reduce DC leakage in a niobium anode are also disclosed.Type: GrantFiled: November 3, 1997Date of Patent: December 26, 2000Assignee: Cabot CorporationInventors: James A. Fife, Jane Jia Liu, Roger W. Steele
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Patent number: 6139593Abstract: A manufacturing method of an anode body of a solid electrolytic capacitor which, for improving the embedded strength of the anode lead with reduced leakage current, successively throws two kinds of valve action metallic powders with different melting-down properties into a single-step press manufacturing die so as to be arranged with the valve action metallic powder whose melting-down property is larger in the neighborhood of the embedded surface of the anode lead.Type: GrantFiled: October 29, 1998Date of Patent: October 31, 2000Assignee: NEC CorporationInventor: Takashi Kono
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Patent number: 6139592Abstract: The object of the invention is to provide a process for producing an organic solid electrolyte capacitor which is diminished in leakage current, and an apparatus for use in practicing the process. The process includes the steps of completing a capacitor element by forming a dielectric oxide film over an anode body of valve metal and subsequently forming a cathode layer of solid conductive organic material over the oxide film, subjecting the capacitor element to an aging treatment, and forming a shell around the capacitor element.Type: GrantFiled: June 18, 1998Date of Patent: October 31, 2000Assignees: Sanyo Electric Co., Ltd., Sanyo Electronic Components Co., Ltd.Inventors: Hidenori Kamigawa, Youichi Kojima, Takeshi Takamatsu, Yasutoshi Sugita, Yasuhiko Ito, Tomohiro Nishio
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Patent number: 6136176Abstract: Capacitor elements made with a solid polymeric electrolyte show reduced leakage current when reformed at about 60-85% of formation voltage during the impregnation phase between successive layers of polymeric electrolyte.Type: GrantFiled: May 21, 1999Date of Patent: October 24, 2000Assignee: Kemet Electronics CorporationInventors: David Alexander Wheeler, Philip Michael Lessner
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Patent number: 6134099Abstract: An electrolytic capacitor in which an conducting polymer as a cathode of the electrolytic capacitor is formed as a homogeneous and densified film on the dielectric layer even extending to the inside of pores of a valvular metal porous body and which obtains a high rate of inducing the capacitance, and have low impedance and high responsiveness at high frequencies. A chemical oxidation polymerization method is utilized to form an conducting polymer layer even extending to the inside of pores of the capacitor element. First, a polymerization reaction is performed in a solution excluding an organic acid-type dopant to form an conducting polymer layer as a densified film on a dielectric layer extending from the surface of the porous body to every inside portions of pores in the pretreatment.Type: GrantFiled: June 3, 1998Date of Patent: October 17, 2000Assignee: Matsushita Electric IndustrialInventors: Emiko Igaki, Masakazu Tanahashi, Chiharu Hayashi
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Patent number: 6099709Abstract: This invention provides an apparatus for producing an electrode foil for use in aluminum electrolytic capacitors with which a high capacitance is obtained while the distortion of the foil and the leakage current can be controlled. At least two electrode plates as cathode are disposed in an electrolytic tank containing an electrolytic solution, and a direct current is supplied between an aluminum foil as anode and the electrode plates. Anodization is conducted continuously by turning the direction of the aluminum foil via rollers and conveying the foil between the electrode plates. During this treatment, the length and the position of the effective sections of the electrode plates are adjusted to keep the length to be at most two-thirds of the distance between an area near the surface of the electrolytic solution and the upper part of the bottom roller, so that the peak value of the anodizing current density appears not at the surface of the electrolytic solution but in the electrolytic solution.Type: GrantFiled: May 15, 1996Date of Patent: August 8, 2000Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Masakazu Tanahashi, Kounosuke Hashio, Mitsuhisa Yoshimura, Daisuke Suzuki, Masanori Okabayashi, Shinji Kabeya
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Patent number: 6094339Abstract: A capacitor including a substantially planar electrochemical cathode including a porous coating; a spirally wound anode having an edge, the edge being disposed opposite and generally parallel to the cathode, the anode being selected from the group including tantalum, aluminum, niobium, zirconium, and titanium; an electrically insulating separator interposed between the cathode and the anode; and an electrolyte disposed between and in contact with the cathode and the anode.Type: GrantFiled: December 4, 1998Date of Patent: July 25, 2000Assignee: Evans Capacitor Company IncorporatedInventor: David A. Evans
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Patent number: 6088218Abstract: The present invention provides a method for producing an electrolytic capacitor including a porous body of a valve metal, an oxide film on a surface of the valve metal, and a conductive polymer layer on a surface of the oxide film. The step of forming the conductive polymer layer on the surface of the oxide film includes the steps of dipping the porous body in a monomer solution; lifting the porous body from the monomer solution and dipping the porous body in an oxidizing solution; and lifting the porous body from the oxidizing solution and allowing the porous body to stand. In the step of dipping the porous body in the oxidizing solution, a period for which the porous body is dipped in the oxidizing solution is equal to or shorter than a period in which 30% of the monomer contained in pores of the porous body diffuses and flows into the oxidizing solution. Alternatively, the volume of the oxidizing solution can be less than three times that of the porous body.Type: GrantFiled: October 27, 1998Date of Patent: July 11, 2000Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Takahiro Hamada, Emiko Igaki, Masakazu Tanahashi, Chiharu Hayashi, Yasunobu Tsuji
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Patent number: 6072694Abstract: The adhesion of a conductive polymer film to an oxidized porous pellet anode is improved by the incorporation of a silane coupling agent in the polymer impregnating solution. The incorporation of the silane coupling agent also decreases leakage current and dissipation factor. Suitable silanes are those of the general formula (R.sup.1 --R.sup.3)--Si--(OR.sup.2).sub.3. Each of R.sup.2 and R.sup.3 is a C.sub.1 -C.sub.6 alkyl group such as methyl, ethyl, or propyl. R.sup.1 can be chosen from a wide variety of organic functional groups such as epoxy, glycidoxy, amino, and pyrrole. The most preferred silane is 3-glycidoxypropyltrimethoxysilane.Type: GrantFiled: September 30, 1998Date of Patent: June 6, 2000Assignee: Kemet Electronics CorporationInventors: Randolph S. Hahn, Philip M. Lessner, Veeriya Rajasekaran
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Patent number: 6059847Abstract: A high performance double layer capacitor having an electric double layer formed in the interface between activated carbon and an electrolyte is disclosed. The high performance double layer capacitor includes a pair of aluminum impregnated carbon composite electrodes having an evenly distributed and continuous path of aluminum impregnated within an activated carbon fiber preform saturated with a high performance electrolytic solution. The high performance double layer capacitor is capable of delivering at least 5 Wh/kg of useful energy at power ratings of at least 600 W/kg.Type: GrantFiled: July 26, 1996Date of Patent: May 9, 2000Assignee: Maxwell Energy Products, Inc.Inventors: C. Joseph Farahmandi, John M. Dispennette
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Patent number: 6040975Abstract: Tantalum powder and solid electrolytic capacitor using the same are disclosed. Cohered powder or Low CV powder is added to High CV powder in order to noticeably enhance an anchor effect during molding and therefore to increase the mechanical strength of a molding. Further, the addition of powder cohered beforehand prevents a contraction ratio from increasing at the time of sintering and thereby prevents the cavity distribution of an anode body from increasing, so that the electrical characteristic is improved.Type: GrantFiled: June 26, 1998Date of Patent: March 21, 2000Assignee: NEC CorporationInventor: Kazuya Mimura
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Patent number: 5986877Abstract: A capacitor having a central electrode body having sintered metal anode with an electrode lead, the anode having a sintered product produced from a tantalum powder having deagglomerated particles such that the product of the volume mean diameter in microns multiplied by the specific surface area measured in m.sup.2 /g is a number in the range of below about 25. Capacitors having a central electrode with the anode produced from a sintered product produced from a heat treated and oxidized tantalum powder wherein the oxidized particle size is greater than about 0.7 m.sup.2 /g. Capacitors are defined in terms of anodes produced from powders having specified ratios of Scott Bulk Density to surface area or ratio of die fill rate to surface area.Type: GrantFiled: July 28, 1998Date of Patent: November 16, 1999Assignee: Cabot CorporationInventors: Viren M. Pathare, Bhamidipaty K. D. P. Rao, James Allen Fife, Hongju Chang, Roger W. Steele, Lee M. Ruch
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Patent number: 5963418Abstract: A multiple anode capacitor (10) having offset terminal leads or strips which maximizes capacitance achieved per volume occupied by the capacitor. More specifically, the invention including a multiple anode aluminum electrolytic capacitor including a cylindrical casing (42), a header (45) crimped to the open end of the casing, the header including a primary anode terminal (41) and a primary cathode terminal (44). Disposed within the casing is a wound or coiled capacitor body (28) having plural anode foils (11, 12, 13), a capacitor foil (14), and dielectric paper separator layers (15, 16) disposed between the cathode and the anodes. In a preferred embodiment, three juxtapositioned anode foils are used, the foils being made from a high purity porous aluminum foil. In addition, each of the dielectric paper separator layers is formed of two kraft capacitor tissue papers (15a, 15b, 16a, 16b).Type: GrantFiled: March 18, 1998Date of Patent: October 5, 1999Assignee: CM Components, Inc.Inventors: John M. Greenwood, Jr., Van Ness Harwood, Jr., Oakland J. Weatherup
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Patent number: 5949639Abstract: A capacitor element for a solid electrolytic capacitor includes a capacitor chip which is a compacted mass of valve metal powder, and an anode wire projecting from a first end face of the capacitor chip. The capacitor chip includes at least one side face which is formed with at least one depression extending toward but short of a second end face of the capacitor chip opposite to the first end face.Type: GrantFiled: September 25, 1997Date of Patent: September 7, 1999Assignee: Rohm Co., Ltd.Inventors: Takahiro Maeda, Shouichi Yanagi, Chojiro Kuriyama
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Patent number: 5922215Abstract: A method for making anode foil plates for use with layered electrolytic capacitors and capacitors made with such plates. A high purity aluminum foil is provided for generation of anode foil plates. Sheets of the foil are highly etched to provide a very high surface area. Following the etch process, the foil is partially cut or punched into plates from the etched sheets in the general shape of the finished capacitor housing with a portion remaining connected to the supporting foil. The supporting foil with the partially punched-out etched plates are subjected to a forming process by applying a voltage to the plates in the presence of an electrolyte to provide formed anode foil plates with edges which do not have to be reformed during capacitor aging and which do not have any particulates at cut edges. The formed anode plates are layered with cathode plates and separators in a capacitor housing with an electrolyte to provide a finished capacitor.Type: GrantFiled: October 15, 1996Date of Patent: July 13, 1999Assignee: Pacesetter, Inc.Inventors: Benjamin D. Pless, William H. Elias, Sam Parler, J. Scott McCall
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Patent number: 5882719Abstract: A combination of static voltage and sweep voltage tests performed on capacitor grade powders gives a valid prediction of performance of eventual solid electrolyte capacitors incorporating such powders.Type: GrantFiled: December 13, 1996Date of Patent: March 16, 1999Assignee: H. C. Starck, Inc.Inventor: Richard M. Creasi, Jr.
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Patent number: 5869196Abstract: Porous metal compacts suitable for use as electrodes are formed through the reduction of a metal billet consisting of multiple filaments of an appropriate valve metal, preferably tantalum, contained within, and spaced apart by, a ductile metal, preferably copper. The filaments are elongated and substantially parallel within the billet. The array of valve metal filaments within the billet is surrounded by a continuous layer of valve metal. This metal is preferably, but not necessarily, the same as that which forms the filaments. The valve metal layer preferably completely surrounds the filament array circumferentially and runs the full length of the filaments. The layer is separated from the array by the same ductile metal that serves to separate the filaments from each other. This same ductile metal forms the surface of the billet, preventing exposure of the valve metal layer.Type: GrantFiled: September 16, 1997Date of Patent: February 9, 1999Assignee: Composite Material Technology, Inc.Inventors: James Wong, Mark K. Rudziak, Terence Wong
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Patent number: 5825611Abstract: Doped tantalum pellets with nitrogen is described wherein the resulting pellets are substantially free of nitride precipitate on their outer surfaces. The tantalum pellets are formed by heating the pellets to a temperature of from about 1000.degree.-1400.degree. C. in a nitrogen gas atmosphere and then in a vacuum which causes nitrogen contacting a tantalum pellet to diffuse into the inner portion of the pellet instead of forming a precipitate. The resulting pellets have improved DCL stability and reliability in comparison to prior art nitrogen-doped tantalum pellets.Type: GrantFiled: January 29, 1997Date of Patent: October 20, 1998Assignee: Vishay Sprague, Inc.Inventor: Yuri L. Pozdeev
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Patent number: 5822178Abstract: A metal tape is employed to form electrodes for an electrolytic capacitor. At least one side surface of the metal tape has rigidly adhered thereto a separating sheet of microporous thermoplastic material. This preferably is done by a thermal process or by cementing. Both surfaces of the metal tape, for example formed of aluminum, may have separating sheets applied thereto. Selected regions of such surface or surfaces may be maintained uncoated, whereby subsequent use as electrodes may enable the attachment to such uncoated regions of terminal contacts.Type: GrantFiled: March 14, 1996Date of Patent: October 13, 1998Assignee: Becromal S.p.A.Inventor: Jean Constanti
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Patent number: 5822177Abstract: An electrolytic capacitor, in particular a tantalum electrolytic capacitor, is provided with a metal anode, in particular a sintered tantalum anode (1), a non-conducting insulating layer applied on it by means of molding the metal anode (1) for forming the dielectric of the electrolytic capacitor, an electrolyte in liquid, pasty or solid form, which forms the cathode of the electrolytic capacitor, and a flat cathode contact (5, 17) for providing current to the electrolyte. The flat cathode contact (5, 7) is provided with an electrically conducting, fractal surface coating (6), at least in the area of its contact surface with the electrolyte.Type: GrantFiled: July 11, 1996Date of Patent: October 13, 1998Assignee: Biotronik Mess-Und Therapiegerate GmbH & Co. Ingenieurburo BerlinInventors: Thomas Popp, Armin Bolz
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Patent number: 5818687Abstract: A capacitor element for use in a solid electrolytic capacitor is formed by sintering metallic powder inside a porous body to produce a chip member having one end of an anode wire buried inside the chip member. The chip member and the anode wire are welded together by laser irradiation within an atmosphere of an inactive gas or an oxidation-reduction gas to form one or more welded portions where the anode wire emerges from the chip member such that the anode wire is made stronger against bending.Type: GrantFiled: February 5, 1997Date of Patent: October 6, 1998Assignee: Rohm Co., Ltd.Inventor: Masatoshi Shimojima
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Patent number: 5812366Abstract: A solid electrolytic capacitor according to the present invention includes a chip substrate segment (12), a sintered chip (21) of metal powder mounted on an upper surface of the chip substrate segment (12), a solid electrolyte layer (23) formed on the chip (21) in electrical insulation from the metal powder of the chip (21) via a dielectric film (22), a resin coating (25) covering the chip (21) with a portion of the solid electrolyte layer (23) exposed, a cathode terminal electrode film (27) formed in electrical conduction with the exposed portion of the solid electrolyte layer (23), and an anode terminal electrode film (28) formed on the chip substrate segment (12) in electrical conduction with the metal powder of the chip (21).Type: GrantFiled: September 3, 1996Date of Patent: September 22, 1998Inventor: Chojiro Kuriyama
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Patent number: 5812367Abstract: A solid electrolytic capacitor is composed of a pair of electrodes and a dielectric film therebetween, wherein one electrode includes a conducting polymer doped with a polyvalent anion and a monovalent anion. The conducting polymer layer may have a multi-layer structure wherein a second or third conductive polymer layer is made of doped thiophene or derivative thereof.Type: GrantFiled: April 1, 1997Date of Patent: September 22, 1998Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Yasuo Kudoh, Kenji Akami, Toshikuni Kojima, Yasue Matsuya, Hiroshi Shimada, Chiharu Hayashi
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Patent number: 5798905Abstract: An oxide film 2 which is so modified as to hold hydrophobic groups 3 on its surface, and further to stabilize an anionic substance 6 among those hydrophobic groups, has an electroconductive polymer layer 7 formed thereupon. The electrolyte capacitor includes the adherence of the hydrophobic groups 3 and anionic substance 6 onto the surface of the oxide film includes exposing an element upon which the oxide film has been formed, to a steam of the hydrophobic group or to a solution containing the hydrophobic group, and then exposing the same element to a steam of the anionic substance or to a solution containing the anionic substance.Type: GrantFiled: August 15, 1997Date of Patent: August 25, 1998Assignee: NEC CorporationInventors: Toshihiko Nishiyama, Isamu Uchida, Koji Sakata
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Patent number: 5772701Abstract: A method for manufacturing tantalum capacitors includes preparing a tantalum compact by cold pressing tantalum powder, placing the compact, along with loose refractory metal powder, in a microwave-transparent casket to form an assembly, and heating the assembly for a time sufficient to effect at least partial sintering of the compact and the product made by the method.Type: GrantFiled: September 5, 1996Date of Patent: June 30, 1998Assignee: Lockheed Martin Energy Research CorporationInventors: April D. McMillan, Robert E. Clausing, William F. Vierow
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Patent number: 5754394Abstract: A capacitor includes a cathode having a coating including an oxide of one of cobalt, molybdenum, and tungsten, a nitride of a metal selected from the group consisting of titanium, vanadium, zirconium, niobium, molybdenum, and tungsten, a carbide of a metal selected from the group consisting of vanadium, niobium, molybdenum, and tungsten, an intercalation carbon cathode, or an electrically conducting polymer selected from polyacetylene, polypyrrole, poly-p-phenylene, polythiophene, poly-3-phenylthiophene, and poly-3-(4-fluorophenyl)-thiophene, an anode including a metal selected from tantalum, aluminum, niobium, zirconium, and titanium, spaced from the coating, and an electrolyte in contact with the coating and the anode.Type: GrantFiled: November 4, 1996Date of Patent: May 19, 1998Assignee: Evans Capacitor Company IncorporatedInventors: David A. Evans, John R. Miller
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Patent number: 5734546Abstract: A capacitor element for a solid electrolytic capacitor is provided which comprises a chip which is a sintered mass of metal powder, and an anode wire projecting from the chip. The anode wire has a nail head end compressively formed for electrical attachment to a surface of the chip. The attachment of the anode wire may be formed by first forming a ball at a forward end of the anode wire and then pressing the ball end against the chip.Type: GrantFiled: September 19, 1995Date of Patent: March 31, 1998Assignee: Rohm Co. Ltd.Inventors: Chojiro Kuriyama, Mamoru Yamagami
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Patent number: 5643432Abstract: A method for forming solid electrolytic capacitors provides for anode lead and body surface with increased dielectric thickness as distinguished from a dielectric thickness formed within the inner anode body such that a capacitance value associated therewith is not substantially decreased. The method includes the steps of anodizing the anode to form a predetermined dielectric thickness on the anode and then soaking the anode in a solvent to impregnate an inner portion thereof with the solvent. The solvent is removed from surface areas desired to be coated by a further dielectric layer and thereafter again anodized whereby additional dielectric build-up is limited to the solvent free areas. The solvent is driven off resulting in a capacitor preform which is reinforced by thickened dielectric without capacitance loss which would result from depositing additional dielectric interiorly in the areas insulated from build-up by the solvent.Type: GrantFiled: July 13, 1995Date of Patent: July 1, 1997Assignee: AVX CorporationInventor: Yong-Jian Qiu
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Patent number: 5629830Abstract: In a solid state electrolytic capacitor, an increase in capacity and a reduction in size and weight are intended. A concave is formed in one end surface of a porous chip formed by hardening metal powder and a synthetic resin is filled in the concave. An anode bar is provided which passes through the synthetic resin to be fixed to the chip. After a dielectric film is formed on the surface of the chip through anodic oxidation, a solid state electrolytic layer made of manganese dioxide is formed on the dielectric film and then, a cathode film is formed thereon. At an end surface of the chip, an insulating film is provided, so that the distance between the lead terminal and the chip is reduced without any short circuit being caused.Type: GrantFiled: May 26, 1995Date of Patent: May 13, 1997Assignee: Rohm Co., Ltd.Inventors: Mamoru Yamagami, Makoto Aoyama
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Patent number: 5622746Abstract: The present invention provides a manganese nitrate coating having high conductivity and solid tantalum anode capacitors having low ESR by using an oven atmosphere which effectively treats all of the anodes in the oven. The manganese nitrate coating of the present invention is produced under highly oxidizing conditions by providing one or more oxidizing agents more active than nitrogen dioxide in the atmosphere of the oven during pyrolysis of manganese nitrate. The oxidizing agents include nitric acid, hydrogen peroxide, ozone, and mixtures thereof.Type: GrantFiled: March 7, 1995Date of Patent: April 22, 1997Assignee: Kemet Electronics CorporationInventors: Randolph S. Hahn, Brian J. Melody, John D. Henley, Jr., John Piper, Shelby J. Poore, Tsung-Yuan Su, John T. Kinard
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Patent number: 5621608Abstract: 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).Type: GrantFiled: November 24, 1995Date of Patent: April 15, 1997Assignee: NEC CorporationInventors: Satoshi Arai, Takashi Fukaumi, Toshihiko Nishiyama, Hiromichi Taniguchi, Atsushi Kobayashi
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Patent number: 5616274Abstract: A stable ion-conductive polymer electrolyte for an electrolytic capacitor comprises: a polymer made up of a prepolymer which has a polyol skeletal structure including polyalkylene oxide units, at least one ammonium salt, and at least one organic solvent. The skeletal structure is exemplified as trimethylol propane, trimethylolol ethane or tetramethylol methane.Type: GrantFiled: October 18, 1994Date of Patent: April 1, 1997Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Teruhisa Kanbara, Yuichiro Tsubaki, Kenichi Takeyama
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Patent number: 5608601Abstract: A capacitor element for a solid electrolytic capacitor is provided which comprises a sintered chip of metal powder, the chip having a first end and a second end opposite to the first end. The chip includes a tapered body whose cross-sectional area reduces from the first end to the second end, and a cathode layer covering the chip excepting at least the first end.Type: GrantFiled: April 24, 1995Date of Patent: March 4, 1997Assignee: Rohm Co., Ltd.Inventor: Chojiro Kuriyama
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Patent number: 5605561Abstract: Tantalum powder obtained by adding magnesium powder to tantalum powder which is prepared by reducing potassium tantalum fluoride with sodium metal, without conventional heat-treatment for agglomeration, to remove oxygen present in the tantalum powder, then washing with an acid and drying; an anode body for electrolytic capacitors produced by sintering the tantalum powder; and, an electrolytic capacitor which comprises the anode body incorporated therein. The tantalum powder has a large specific surface area and accordingly, the electrolytic capacitor in which the anode body produced from the tantalum powder is incorporated has an extra high capacity, i.e., a CV ranging from 70000 to 80000. The probability of causing ignition during the production process is substantially reduced and thus the tantalum powder can be handled with safety.Type: GrantFiled: September 6, 1995Date of Patent: February 25, 1997Assignee: Starck Vtech Ltd.Inventors: Katsuo Iwabuchi, Tadashi Komeya, Hiroshi Oki, Dieter Behrens
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Patent number: 5580367Abstract: An improved flaked tantalum powder and process for making the flaked powder are disclosed. The powder is characterized by having a Scott density greater than about 13 g/in.sup.3 and preferably at least about 90% of the flake particles having no dimension greater than about 55 micrometers. Agglomerates of the flaked tantalum powder, provide improved flowability, green strength and pressing characteristics compared to conventional flaked tantalum powders. The improved flaked tantalum powder can be made by preparing a flaked tantalum and then reducing the flake size until a Scott density greater than about 18 g/in.sup.3 is achieved. The invention also provides pellets and capacitors prepared from the above-described flaked tantalum powder.Type: GrantFiled: April 17, 1995Date of Patent: December 3, 1996Assignee: Cabot CorporationInventor: James A. Fife
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Patent number: 5560761Abstract: Tantalum powder used as an anode material for an electrolytic capacitor comprising usual tantalum powder (having an average particle size ranging from 1.0 to 5.0 .mu.m) mixed with tantalum powder having an average particle size on the order of nanometers (ranging from 10 to 500 nm) in an amount ranging from 1 to 25 parts by weight per 100 parts by weight of the former; an anode body for use in an electrolytic capacitor which is produced by sintering the tantalum powder; an electrolytic capacitor in which the anode body is incorporated.Type: GrantFiled: September 6, 1995Date of Patent: October 1, 1996Assignee: Starck Vtech Ltd.Inventor: Hiroo Naito