JP4901647B2 - Surface mount type electrolytic capacitor - Google Patents

Description

  The present invention relates to a surface mount electrolytic capacitor, and more particularly to a resin case thereof.

  It is necessary to connect a decoupling element mainly composed of a capacitor to a CPU (Central Processing Unit) such as a computer in order to prevent noise superimposed on the power supply line. The need for this has increased with the increase in CPU speed (increase in clock frequency). Similarly, in digital home appliances and communication devices other than personal computers and servers, the need for connecting a decoupling element to the power supply line is increasing as the speed of CPUs and signal processing LSIs increases.

  Some decoupling elements are called transmission line type elements or transmission line type noise filters. For example, a three-terminal capacitor can be used as a transmission line type decoupling element. As a three-terminal capacitor, a surface mount electrolytic capacitor having a capacity of several hundreds μF, an ESR (equivalent series resistance) of 5 mΩ or less in a frequency band of 100 MHz, and an ESL (equivalent series inductance) of about 1 pH has already been developed. Has been put to practical use.

  A surface-mount electrolytic capacitor is generally formed by laminating a plurality of electrolytic capacitor elements. Each electrolytic capacitor element is formed as a positive electrode body by forming a dielectric film on the surface excluding both ends of the anode part made of a foil-like or plate-like valve action metal, and a solid electrolyte layer and a conductive substance on the surface. A layer is formed to form a cathode portion. In the plurality of laminated electrolytic capacitor elements, the anode parts and the cathode parts of the electrolytic capacitor elements adjacent in the vertical direction are connected to each other using a conductive paste. Moreover, the anode part and the cathode part of the electrolytic capacitor element located in the lowermost layer are connected to the anode terminal and the cathode terminal through the conductive paste, respectively.

  As a conventional surface mount electrolytic capacitor, there is one in which a laminated body in which a plurality of electrolytic capacitor elements described above are stacked is housed in a resin case (see, for example, Patent Document 1). 2 (a) is an exploded perspective view thereof, FIG. 2 (b) is an external perspective view with the exterior case (upper cover) removed, FIG. 2 (c) is an external perspective view with the exterior case attached, FIG. 2D is a bottom view.

  More specifically, the surface mount type electrolytic capacitor shown in FIGS. 2A to 2D includes an outer case 21, an electrolytic capacitor element laminate (or an electrolytic capacitor element alone) 22, and a resin case 25. Yes.

  The outer case 21 is made of, for example, a resin and has a box shape (a rectangular parallelepiped) with a lower portion opened. The vertical and horizontal sizes of the outer case 21 are made slightly larger than the resin case 25.

  The electrolytic capacitor element laminate 22 is configured as described above, and the anode portion 23 and the cathode portion 24 are exposed on the outer peripheral surface thereof. In the figure, the anode part 23 and the cathode part 24 are drawn so as to be in contact with each other, but they are insulated from each other.

  The resin case 25 has a box shape (a rectangular parallelepiped) with an open top, and is integrally formed with an anode terminal 26 and a cathode terminal 27 made of a metal plate by molding. Most of the upper surfaces of the anode terminal 26 and the cathode terminal 27 are exposed on the inner bottom surface of the resin case 25, and the entire lower surface is exposed on the outer bottom surface of the resin case 25. That is, the resin case 25 has an anode terminal 26 and a cathode terminal 27, a bottom plate portion made of resin filling the space therebetween, and a side wall portion made of resin formed substantially perpendicular to the periphery of the bottom plate portion. A part (both ends) of the anode terminal 26 and the cathode terminal 27 protrudes from the side wall portion to the outside.

  The electrolytic capacitor element laminate 22 is accommodated in the resin case 25. At this time, a conductive paste is disposed between the lower surface of the electrolytic capacitor element laminate 22 and the inner bottom surface of the resin case 25, and the anode portion 23 is connected to the anode terminal 26 and the cathode portion 24 is connected and fixed to the cathode terminal 27. .

  The outer case 21 is covered from the upper side of the resin case 25 and fixed to the electrolytic capacitor element laminate 22 and the resin case 25 with an adhesive or the like.

JP 2006-128247 A

  In a conventional surface mount electrolytic capacitor in which an electrolytic capacitor element or a laminate thereof is accommodated in a resin case, the electrolytic capacitor element or the laminate of the electrolytic capacitor element accommodated in the resin case and the anode portion and the anode terminal and cathode of the resin case The terminals are connected to each other using a conductive paste. At this time, if the amount of the conductive paste is too large, short-circuit failure occurs due to bridging to the counter electrode. On the other hand, when there is little conductive paste, a passage resistance defect or an ESR defect occurs. Therefore, it is necessary to inspect the connection state of the conductive paste when manufacturing the surface mount electrolytic capacitor.

  However, in the conventional surface mount electrolytic capacitor, the connection state of the conductive paste cannot be visually recognized from the outside, and the resin case must be destroyed in order to know the connection state of the conductive paste. Therefore, the actual product has a problem that the connection state of the conductive paste cannot be known.

  Therefore, an object of the present invention is to provide a surface mount electrolytic capacitor that can easily confirm the connection state of the conductive paste from the outside without destroying the resin case.

In order to solve the above problems, the present invention is an electrolytic capacitor element comprising an electrode, comprises a terminal connected to the electrode, the surface mount capacitor comprising a resin case for accommodating the electrolytic capacitor element, the electrolyte The capacitor element is a laminate in which a single flat electrolytic capacitor element or a plurality of flat electrolytic capacitor elements are laminated, and has a lower surface at which at least a part of the electrode is exposed, and is used for the resin case. Is a transparent or translucent resin, and the resin case has a box shape with an open top, an internal bottom surface at which at least a part of the terminal is exposed, and the bottom surface is the internal bottom surface. The electrolytic capacitor element is accommodated in the resin case so as to face each other, and is guided between the electrode exposed on the lower surface and the terminal exposed on the inner bottom surface. So as to be connected by gender paste, characterized in that to be able to visually confirm the connection state between the between the electrode terminals.

  Further, the present invention is a plate-like electrolytic capacitor element having an anode part at the end and a cathode part at the center, or an electrolytic capacitor element laminate formed by laminating the electrolytic capacitor element, and is flat. The anode terminal connected to the anode part and the cathode terminal connected to the cathode part, and mechanically fixing the anode terminal and the cathode terminal, and filling between the anode terminal and the cathode terminal, A resin case having a bottom plate that exposes part of the upper and lower surfaces of the anode terminal and the cathode terminal, and a side wall formed substantially perpendicular to the bottom plate, and an upper portion of the resin case and one of the side walls A surface-mount type electrolytic capacitor comprising a box-shaped outer case covering a portion, wherein the resin case is formed of a transparent or translucent resin.

  According to the present invention, in a surface mount type electrolytic capacitor including an electrolytic capacitor element and a resin case for housing the electrolytic capacitor element, the resin case is made transparent or translucent, so that the electrolytic capacitor element is not destroyed. The connection state of the conductive paste for connecting the electrode and the terminal provided on the resin case can be visually recognized from the outside. Thereby, 100% inspection is possible. In addition, since the time required for inspection can be greatly reduced compared to destructive inspection, fluctuations in the applied amount of the conductive pace can be detected quickly when many products are manufactured continuously. The amount of sexual pace applied can be adjusted in a timely manner.

  Hereinafter, the surface mount electrolytic capacitor of the present invention will be described in detail with reference to the drawings.

  1A to 1D show a surface mount electrolytic capacitor according to an embodiment of the present invention. 1A is an exploded view showing a case where a resin case 15, an electrolytic capacitor element laminate (or a single electrolytic capacitor element) 12 and an outer case (upper cover) 11 are separated, and FIG. 1B is an electrolytic capacitor element. FIG. 1C is an external perspective view after the laminated body 12 is accommodated in the resin case 15, FIG. 1C is an external perspective view after the exterior case is covered, and FIG. 1D is a bottom view thereof.

  The surface mount electrolytic capacitor according to the present embodiment has substantially the same configuration as the conventional surface mount electrolytic capacitor shown in FIGS. 2A to 2D, and is used for the resin case 15 as will be described later. The difference is that the resulting resin is transparent or opaque. Hereinafter, the surface mount electrolytic capacitor according to the present embodiment will be described in detail.

  The surface mount type electrolytic capacitor according to the present embodiment has an outer case 11, an electrolytic capacitor element laminate 12, and a resin case 15.

  The outer case 11 is made of an opaque resin and has a box shape (a rectangular parallelepiped) having an open lower portion. The vertical and horizontal sizes of the outer case 11 are made slightly larger than the resin case 15.

  The electrolytic capacitor element laminate 12 is formed by laminating a plurality of electrolytic capacitor elements. Each electrolytic capacitor element is formed as a positive electrode body by forming a dielectric film on the surface excluding both ends of the anode part made of a foil-like or plate-like valve action metal, and a solid electrolyte layer and a conductive substance on the surface. A layer is formed to form a cathode portion. That is, the electrolytic capacitor element has a pair of anode portions provided at both ends, and a cathode portion provided therebetween. In the plurality of laminated electrolytic capacitor elements, the anode portions and the cathode portions of the vertically adjacent electrolytic capacitor elements are connected to each other using a conductive paste. An anode portion 13 and a cathode portion 14 are exposed on the outer peripheral surface of the electrolytic capacitor element laminate 12. In the drawing, the anode portion 13 and the cathode portion 14 are drawn so as to be in contact with each other, but they are insulated from each other.

  The resin case 15 has a box shape (a rectangular parallelepiped) with an open top, and is integrally formed with a pair of anode terminal 16 and cathode terminal 17 made of a flat metal plate by molding. The pair of anode terminal 16 and cathode terminal 17 are arranged so as to correspond to the anode portion 13 and the cathode portion 14 of the electrolytic capacitor laminate 12. Most of the upper surfaces of the anode terminal 16 and the cathode terminal 17 are exposed at the inner bottom surface of the resin case 15, and substantially the entire lower surface is exposed at the outer bottom surface of the resin case 15. That is, the resin case 15 mechanically fixes the anode terminal 16 and the cathode terminal 17 and fills the space between the bottom plate portion made of resin, and the four side wall portions made of resin formed substantially perpendicular to the periphery of the bottom plate portion. have. A part (both ends) of the anode terminal 16 and the cathode terminal 17 protrudes from the side wall portion to the outside.

  The electrolytic capacitor element laminate 12 is accommodated in the resin case 15. At this time, the conductive paste is disposed at a position corresponding to the anode portion 13 and the cathode portion 14 between the lower surface of the electrolytic capacitor element laminate 12 and the inner bottom surface of the resin case 15, and is exposed to the lower surface of the electrolytic capacitor element laminate. The anode portion 13 is connected and fixed to the anode terminal 16, and the cathode portion 14 is connected and fixed to the cathode terminal 17.

  The outer case 11 is covered from the upper side of the resin case 15 and is fixed to the electrolytic capacitor element laminate 12 and the resin case 15 with an adhesive or the like. The outer image case 11 covers the upper surface of the resin case and covers substantially the entire outer side surface of the side wall.

  In the present embodiment, a transparent or translucent resin is used as the material of the resin case 15, unlike a conventional surface mount electrolytic capacitor. Examples of the transparent or translucent resin include an epoxy resin and a polyimide resin.

  Since the resin used for the resin case 15 is transparent or translucent, the electrolytic capacitor element laminate 12 is inserted into the resin case 15 even after the electrolytic capacitor element laminate 12 is inserted into the side surface of the electrolytic capacitor element laminate 12 as shown in FIG. The application amount of the applied conductive paste 18 can be easily recognized. Further, as shown in FIG. 1D, the bottom surface of the electrolytic capacitor element laminate 12 can be seen from the outer bottom surface side of the resin case 15 through the space between the anode terminal 16 and the cathode terminal 17. Thereby, the bridge | bridging to the cathode of the electrically conductive paste 19 for anode connection or the bridge | bridging to the anode of the electrically conductive paste 20 for cathode connection can be visually recognized easily. Moreover, when the conductive paste 19 for anode connection and the conductive paste 20 for cathode connection are not visible at all, it can be determined that the coating amount is insufficient.

  As described above, in the surface mount electrolytic capacitor according to the present embodiment, the application amount of the conductive paste 18 applied to the side surface of the electrolytic capacitor element laminate 12, the anode portion 13 of the electrolytic capacitor element laminate 12, and The application amount of the conductive pastes 19 and 20 used for connection between the cathode portion 14 and the anode terminal 16 and the cathode terminal 17 provided on the resin case 15 can be visually recognized without destroying the resin case 15.

It is a figure which shows the surface mount-type electrolytic capacitor which concerns on one embodiment of this invention, Comprising: (a) is an exploded view, (b) is an external appearance perspective view of the state which accommodated the electrolytic capacitor element in the resin case, (c) These are the external appearance perspective views which show the state after attaching an exterior case, and (d) is a bottom view. It is a figure which shows the conventional surface mount-type electrolytic capacitor, (a) is an exploded view, (b) is an external appearance perspective view which shows the state which accommodated the electrolytic capacitor element in the resin case, (c) is a cover with an exterior case The external appearance perspective view which shows the state after having performed, and (d) are bottom views.

Explanation of symbols

11, 21 Exterior case 12, 22 Electrolytic capacitor element laminate 13, 23 Anode part 14, 24 Cathode part 15, 25 Resin case 16, 26 Anode terminal 17, 27 Cathode terminal 18 Conductive paste for electrolytic capacitor element side coating 19 Anode Conductive paste for connection 20 Conductive paste for cathode connection

Claims (5)

In a surface mount capacitor including an electrolytic capacitor element including an electrode and a resin case including a terminal connected to the electrode and containing the electrolytic capacitor element,
The electrolytic capacitor element is a laminated body in which a single flat electrolytic capacitor element or a plurality of flat electrolytic capacitor elements are laminated, and has a lower surface where at least a part of the electrode is exposed,
The resin used for the resin case is a transparent or translucent resin, and the resin case has a box shape with an open top and an inner bottom surface where at least a part of the terminal is exposed,
The electrolytic capacitor element is accommodated in the resin case with the lower surface facing the inner bottom surface, and the electrode exposed on the lower surface and the terminal exposed on the inner bottom surface are connected by a conductive paste. ,
A surface-mounted capacitor characterized in that a connection state between the electrode and the terminal can be visually recognized. The electrode has a pair of anode parts provided at both ends, and a cathode part provided between the pair of anode parts,
2. The surface mount capacitor according to claim 1 , wherein the terminal has a pair of anode terminal and cathode terminal provided corresponding to the pair of anode part and cathode part, respectively. The terminal is a surface-mount capacitor according to claim 1 or 2, characterized in that at least a part is exposed on the lower surface of the resin case. The surface mount capacitor according to any one of claims 1 to 3 , further comprising a cover that covers an upper portion and an outer surface of the resin case. A plate-like electrolytic capacitor element having an anode part at the end and a cathode part at the center, or an electrolytic capacitor element laminate formed by laminating the electrolytic capacitor element;
Both are flat and have an anode terminal connected to the anode part and a cathode terminal connected to the cathode part,
A bottom plate for mechanically fixing the anode terminal and the cathode terminal, filling a space between the anode terminal and the cathode terminal, and exposing a part of the upper surface and the lower surface of the anode terminal and the cathode terminal, respectively, and A resin case having a side wall formed substantially perpendicular to the bottom plate;
A surface-mount type electrolytic capacitor comprising a box-shaped outer case covering an upper part of the resin case and a part of the side wall,
A surface mount type electrolytic capacitor, wherein the resin case is made of a transparent or translucent resin.

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