JP2008021772A - Chip-type solid electrolytic capacitor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide further low ESL of a chip-type solid electrolytic capacitor to be used for various kinds of electronic equipment. <P>SOLUTION: The solid electrolytic capacitor consists of a capacitor element 1 formed such that each of anodes having anode electrode portions of the same profile and substantially the same area protruding on opposite sides is separated into the anode electrode portion and a cathode forming portion by an insulating portion, and a solid electrolytic layer and a cathode layer are formed on the cathode forming portion to form a cathode electrode portion; anode and cathode electrodes 7, 8 joined to each of the anode and cathode electrode portions by adjacently disposing a plurality of capacitor elements 1; and an armoring resin 10 integrally covering the capacitor element 1 other than a part of the anode and cathode terminals 7, 8. With this configuration, since the anode/cathode portion can be closely disposed on the same line in the state of the capacitor element 1 and the anode and cathode terminals 7, 8 are alternately closely disposed on each of opposite sides on a lower surface as a mounting surface, currents flowing between the anode and cathode terminals 7, 8 are canceled. Thus, ESL can be reduced to be one-Nth (N is an integer of two or more). <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a chip-type solid electrolytic capacitor using a conductive polymer as a solid electrolyte among capacitors used in various electronic devices.

  Along with the increase in frequency of electronic equipment, capacitors that are one of the electronic components have been required to have better impedance characteristics in the high frequency range than before. Various solid electrolytic capacitors using a highly conductive polymer as a solid electrolyte have been studied.

  In recent years, a solid electrolytic capacitor used around a CPU of a personal computer has been strongly demanded to have a small size and a large capacity. Further, not only a low ESR (equivalent series resistance) is reduced in response to a higher frequency but also a noise. There is a strong demand for low ESL (equivalent series inductance) excellent in removal and transient response, and various studies have been made to meet such a demand.

  4 (a) and 4 (b) are a perspective view and a bottom view showing the configuration of this type of conventional chip-type solid electrolytic capacitor proposed by the present inventors, and FIGS. 5 (a) to 5 (c) are the same. 1 is a perspective view of a cathode lead frame used in a chip-type solid electrolytic capacitor, a perspective view of the anode lead frame, and a perspective view of a state in which the two lead frames are superposed.

  4 and 5, reference numeral 11 denotes a capacitor element. The capacitor element 11 has an insulating property at a predetermined position of an anode body in which an aluminum foil as a valve metal is roughened and a dielectric oxide film is formed on the surface. A resist portion 11a is provided to separate the anode electrode portion 11b and the cathode forming portion, and a solid electrolyte layer made of a conductive polymer and a cathode layer made of carbon and silver paste are sequentially laminated on the dielectric oxide film of the cathode forming portion. This is formed by forming the cathode electrode portion 11c.

  Reference numeral 12 denotes an anode lead frame. The anode lead frame 12 has an anode joint portion 12b to which the anode electrode portion 11b of the capacitor element 11 is joined at one end of the flat portion 12a, and an anode terminal portion 12c for mounting. A plurality are provided on the lower surface. The anode terminal portion 12c is formed so as to protrude from the flat surface portion 12a to the mounting surface side by bending a single substrate.

  Reference numeral 13 denotes a cathode lead frame. The cathode lead frame 13 is mounted and joined with the cathode electrode portion 11c of the capacitor element 11, and is mounted on the flat portion 12a of the anode lead frame 12 via an insulating layer (not shown). A plurality of flat surface portions 13a and mounting cathode terminal portions 13b are provided on the lower surface. The cathode terminal portion 13b is formed so as to protrude from the flat surface portion 13a to the mounting surface side by bending a single substrate. Reference numeral 13 c denotes a guide wall provided for positioning and fixing the cathode electrode portion 11 c of the capacitor element 11. The insulating layer (not shown) may be formed by printing a polyimide film having a thickness of about 10 μm or a resin.

  14 is an insulating exterior resin that integrally covers the plurality of capacitor elements 11, the anode lead frame 12, and the cathode lead frame 13 with the mounting surfaces of the anode terminal portion 12c and the cathode terminal portion 13b exposed. In (a), in order to make the internal structure easy to understand, this is illustrated with the exterior resin 14 removed.

  The conventional chip-type solid electrolytic capacitor configured as described above has a structure in which the anode lead frames 12 are arranged so as to flow in the direction opposite to the direction of the current flowing in the cathode lead frame 13, so Since the currents flowing through each other cancel each other, ESL can be greatly reduced (reference: 270 pH).

As prior art document information related to the invention of this application, for example, Patent Document 1 is known.
JP 2006-80427 A

  However, although the conventional chip-type solid electrolytic capacitor has the effect that the ESL can be greatly reduced as compared with the conventional product, it is further improved for the low ESL required at a higher level. There was a problem that it was necessary.

  An object of the present invention is to provide a chip-type solid electrolytic capacitor capable of solving such a conventional problem and realizing further reduction in ESL.

  In order to solve the above-mentioned problems, the present invention provides an insulating part at a predetermined position of an anode body made of an aluminum foil having a dielectric oxide film layer formed on the surface thereof, and separates it into an anode electrode part and a cathode forming part. Capacitor element in which a cathode electrode portion is formed by sequentially laminating a solid electrolyte layer made of a conductive polymer and a cathode layer made of carbon and silver paste on the cathode forming portion, and an anode electrode portion and a cathode electrode of the capacitor element An anode terminal and a cathode terminal, each of which is bonded to the top surface, and an insulating exterior resin that integrally covers the capacitor element, the anode terminal, and the cathode terminal except for the bottom surface that is at least the mounting surface of the anode terminal and the cathode terminal. In the chip-type solid electrolytic capacitor as described above, as the anode body, anode electrode portions having substantially the same shape and the same area are provided so as to protrude at least on opposite sides. To form a capacitor element using what was, and is obtained by the construction coated integrally with the exterior resin of this capacitor element was plurality adjacently arranged on the same plane.

  As described above, the chip-type solid electrolytic capacitor according to the present invention has a configuration in which anode electrode portions having substantially the same shape and the same area are provided so as to protrude at least on opposite sides of the anode body. The anode part and the cathode part can be arranged at very close positions in the vicinity, and a plurality of the capacitor elements are arranged adjacent to each other on the anode terminal and the cathode terminal to be joined to form a bottom surface as a mounting surface. In order to realize a multi-terminal structure in which anode terminals and cathode terminals are alternately arranged in close proximity to each other, the currents flowing between the anode terminal and cathode terminal cancel each other, and the ESL is reduced. Not only can it be greatly reduced, but by covering a plurality of capacitor elements adjacent to each other in this way with an exterior resin, ES The is further intended effect is obtained that it is possible to reduce the 1 / plural.

(Embodiment)
Hereinafter, the invention described in the entire claims of the present invention will be described by using embodiments.

  1A to 1D are a plan view, a front view, a bottom view, and a side view showing a configuration of a chip-type solid electrolytic capacitor according to an embodiment of the present invention, and FIG. FIG. 3A to FIG. 3D are manufacturing process diagrams showing a manufacturing process of a capacitor element used for the chip-type solid electrolytic capacitor.

  1 to 3, reference numeral 1 denotes a capacitor element. The capacitor element 1 is formed on the surface of an anode body 2 made of an aluminum foil provided with anode electrode portions 2 a having substantially the same shape and the same area on opposite sides. After forming a dielectric oxide film layer (not shown), an insulating resist portion 3 is provided at a predetermined position to be separated into an anode electrode portion 2a and a cathode forming portion 4, and a conductive polymer is formed on the surface of the cathode forming portion 4. The cathode electrode portion 6 is formed by sequentially laminating a solid electrolyte layer 5a made of carbon and a cathode layer 5b made of carbon and silver paste.

  7 is a plate-like anode terminal in which the anode electrode portion 2a of the capacitor element 1 is joined to the upper surface, and 8 is a plate-like cathode terminal in which the cathode electrode portion 6 of the capacitor element 1 is joined to the upper surface. The cathode terminal 8 is formed so as to be independent by punching out a single substrate 9, and two capacitor elements 1 can be arranged adjacent to each other to be joined. The anode terminal 7 and the anode electrode portion 2a are joined by resistance welding (welding mark 7a), and the cathode terminal 8 and the cathode electrode portion 6 are joined by a conductive silver paste (not shown).

  In this way, the two capacitor elements 1 are integrated with each other in such a manner that a part of the anode terminal 7 and the cathode terminal 8 which are adjacently bonded to each other on the same surface are exposed on the outer surface. A coated insulating exterior resin (in FIG. 1 (a), the exterior resin 10 is illustrated in order to make the internal structure easier to understand), and thus a chip-type chip that can be surface mounted. This is a solid electrolytic capacitor.

  The thus configured chip-type solid electrolytic capacitor according to the present embodiment can realize a multi-terminal structure in which the anode terminal 7 and the cathode terminal 8 are alternately arranged close to each other on the opposite sides of the bottom surface serving as the mounting surface. Therefore, not only can the currents flowing between the anode terminal 7 and the cathode terminal 8 cancel each other to greatly reduce the ESL, but the capacitor elements configured in this way can be identical. This chip-type solid electrolytic capacitor has a special effect that the ESL can be further reduced to 1/2 by arranging two adjacently on the surface and integrally covering with the exterior resin. When the ESL was measured, it showed a low value of 34 pH, and the ESL can be greatly reduced compared to the conventional product (270 pH).

  In the present embodiment, the number of capacitor elements 1 that are disposed close to the anode terminal 7 and the cathode terminal 8 and are integrally covered with the exterior resin 10 is two, but the present invention is limited to this. It may be three or more, and the ESL decreases as the number increases.

  The chip-type solid electrolytic capacitor according to the present invention has an effect that the ESL can be greatly reduced, and is particularly useful as a field where high frequency response is required.

(A) The top view which showed the structure of the chip-type solid electrolytic capacitor by one embodiment of this invention, (b) The front view, (c) The bottom view, (d) The side view Plan view showing anode and cathode terminals used in the chip-type solid electrolytic capacitor (A)-(d) Manufacturing process figure which showed the manufacturing process of the capacitor | condenser element used for the same chip type solid electrolytic capacitor (A) The perspective view which showed the structure of the conventional chip-type solid electrolytic capacitor, (b) The bottom view (A) The perspective view which showed the cathode lead frame used for the same chip type solid electrolytic capacitor, (b) The perspective view which showed the anode lead frame, (c) The state which piled up both the lead frames was shown Perspective view

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Capacitor element 2 Anode body 2a Anode electrode part 3 Resist part 4 Cathode formation part 5a Solid electrolyte layer 5b Cathode layer 6 Cathode electrode part 7 Anode terminal 7a Welding mark 8 Cathode terminal 9 Base material 10 Exterior resin

Claims (2)

An insulating part is provided at a predetermined position of an anode body made of an aluminum foil having a dielectric oxide film layer formed on the surface, and separated into an anode electrode part and a cathode forming part, and a solid made of a conductive polymer is formed on the cathode forming part Capacitor element in which a cathode electrode portion is formed by sequentially stacking an electrolyte layer, a cathode layer made of carbon and silver paste, and an anode terminal and a cathode in which the anode electrode portion and the cathode electrode portion of the capacitor element are joined to the upper surface, respectively. In the chip-type solid electrolytic capacitor comprising a terminal and an insulating exterior resin in which the capacitor element, the anode terminal and the cathode terminal are integrally covered except for at least the bottom surface which is the mounting surface of the anode terminal and the cathode terminal, the anode body As a capacitor element, an anode electrode portion having substantially the same shape and the same area protruding from at least opposite sides is provided. And, and, Chip solid electrolytic capacitor coated integrally at a plurality adjacently to the exterior resin to the capacitor element a same plane on. 2. The chip-type solid electrolytic capacitor according to claim 1, wherein anode electrode portions provided so as to protrude on opposite sides of the anode body are provided so as to protrude asymmetrically at one end portion which is a diagonal position of each side.

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