JP2009004686A - Surface-mounting thin capacitor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a surface-mounting thin capacitor capable of preventing displacement when mounted on a substrate. <P>SOLUTION: In the surface-mounting thin capacitor, a capacitor element including an oxide film serving as a dielectric layer and a conductive function polymeric molecule serving as a solid electrolyte layer is stored in an exterior case to whose bottom surface an electrode terminal for surface-mounting is formed. The oxide film is formed on a surface of an anodic body made of a foil-shaped valve action metal whose surface is extended. The exterior case consists of a case 2 opened at an upper side, and a cover 1 covering the upper side and a lateral side of the case 2. A convex part 1a projecting below than a mounting surface of an anode terminal 3 and a cathode terminal 4 is provided at four corners of the cover 1 opposed to a mounting surface of the cover 1. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a surface-mount thin capacitor that is housed in an exterior case and has electrode terminals on its lower surface.

  Capacitor that functions as a transmission line type element or a transmission line type noise filter, has a high capacity, has an ESR (equivalent series resistance) in the frequency band of 100 MHz of several mΩ or less, and an ESL (equivalent series inductance) of about 1 pH A surface mount thin capacitor having both the characteristics of a filter and a filter is known (for example, Patent Document 1).

  Furthermore, a surface mount thin capacitor in which a similar capacitor element is housed in a highly reliable exterior case is known (for example, Patent Document 2).

  FIG. 3 shows the outer shape of a surface mount thin capacitor of a conventional example (Patent Document 2). 3A is a front view, FIG. 3B is a side view, and FIG. 3C is a bottom view.

  In FIG. 3, the case 2 has a box shape with the top opened, and is a resin case having two anode terminals 3 and one cathode terminal 4 provided on the bottom. The cover 1 is located above and on the side of the case 2. This is a resin cover that covers the surface. In such an outer case, an oxide film layer is formed on the surface of the porous valve metal body, anode lead portions are formed on both ends, and a cathode layer including a solid electrolyte layer is formed on the oxide film layer. The capacitor element is accommodated.

  That is, in the conventional surface mount thin capacitor, the anode terminal 3 and the cathode terminal 4 are formed on the bottom surface of the case 2 on the terminal mounting surface side, and the capacitor element is formed in a single layer or laminated thereon, and the cover 1 of the exterior resin is covered. It is a structure. At this time, the height from the mounting surface of the lower end of the cover 1 of the exterior resin is substantially the same as the height of the upper surfaces of the anode terminal 3 and the cathode terminal 4.

JP 2002-313676 A JP 2006-128247 A

  In a conventional surface-mount thin capacitor, the main body is likely to float due to the surface tension of the paste solder melted during mounting on the printed board, and may be displaced from the printed board mounting position. SUMMARY OF THE INVENTION An object of the present invention is to provide technical means for preventing displacement of a surface-mounted thin capacitor when mounted on a substrate.

  In order to solve the above-mentioned problems, the surface mount thin capacitor of the present invention is a conductive functional polymer having an oxide film formed on the surface of an anode body made of an expanded foil-like valve metal as a dielectric layer. In a surface mount thin capacitor in which a capacitor element having a solid electrolyte layer is housed in an exterior case having a bottom surface provided with electrode terminals for surface mounting, the side surface portion of the exterior case is below the mounting surface of the electrode terminals. A plurality of projecting convex portions are provided.

  The outer case is composed of a main body case that is open on the upper side and an outer case that covers the upper side and the side of the main body case, and is protruded downward from the mounting surface of the electrode terminal on the side surface of the outer case. A part may be provided.

  The convex portion may be provided at a corner of the bottom surface of the exterior case.

  The convex portion may be provided along the opposite side of the bottom surface of the exterior case.

  According to the present invention, the main body can be supported by the convex portion provided at the lower end portion of the side surface of the exterior resin cover of the surface mount thin capacitor when the printed circuit board is mounted, and the main body is lifted by the surface tension of the paste solder melted during the mounting of the board. There is an effect of suppressing, and mounting position shift can be prevented.

(Embodiment 1)
1A and 1B are views showing the outer shape of a surface-mount thin capacitor according to Embodiment 1 of the present invention. FIG. 1A is a front view, FIG. 1B is a side view, and FIG. FIG.

  A surface mount thin capacitor according to a first embodiment of the present invention will be described with reference to FIG. The case (main body case) 2 has a box shape with the top opened, and is a resin case having two anode terminals 3 and one cathode terminal 4 formed on the bottom surface. The cover (outer case) 1 is the case 2. It is the resin-made cover which was covered so that the upper side and side might be covered. In such an outer case, an oxide film layer is formed on the surface of the porous valve metal body and anode lead portions are provided at both ends, and a solid electrolyte layer of a conductive functional polymer is formed on the oxide film layer. The capacitor element in which the cathode layer containing is formed is stored. At this time, the upper surfaces of the anode terminal 3 and the cathode terminal 4 and the anode lead portion and the cathode layer of the capacitor element are connected to each other at the bottom inside the case 2 by a conductive adhesive.

  In the production of the cover 1 of the surface mount thin capacitor, concave portions are provided at the four corners of the mounting surface end portion of the side surface of the outer resin cover mold, and the convex portion 1a is formed on the cover 1 by injecting the resin. The protruding amount of the convex portion 1a, that is, the protruding amount based on the mounting surface (lower surface) of the anode terminal 3 and the cathode terminal 4 is set to a value approximately equal to or slightly smaller than the thickness of the paste solder.

  In this way, the convex portions 1a provided at the lower ends of the four corners of the side surface of the exterior resin cover of the surface mount thin capacitor when the printed circuit board is mounted can serve as four legs to support the main body. It is possible to prevent the main body from being lifted due to the surface tension, and to prevent mounting position shift.

(Embodiment 2)
2A and 2B are diagrams showing the outer shape of the surface-mount thin capacitor according to the second embodiment of the present invention. FIG. 2A is a front view, FIG. 2B is a side view, and FIG. FIG.

  That is, FIG. 2 is a form in which the length in the lateral direction of the convex portion 1a formed at the end portion of the mounting surface of the cover 1 made of the exterior resin of the surface mount thin capacitor is extended as compared with FIG. Here, although the convex part 1a is provided along the opposite side in the bottom face of an exterior case, the raising of the main body by the melted paste solder at the time of board | substrate mounting can also be suppressed by such a convex part 1a. .

  Note that the protruding shape of the convex portion is not limited to the above-described form, and the length, width, and shape of the mounting surface end of the exterior resin cover mold side surface are within the scope not departing from the gist of the present invention. It is included in the present invention. In addition, as for the position where the convex portion is provided, for example, when using a main body case with the top opened as an exterior case and a lid that covers only the upper part, the side surface of the main body case has a mounting surface of the electrode terminal. Also, a convex portion protruding downward can be provided and used as a leg portion.

  The external shape of the surface mount thin capacitor of the present invention can be generally applied to an electronic component in which an electrode is formed on the bottom surface of a product of a type that is surface mounted on a printed board.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows the external appearance of the surface mount thin capacitor by Embodiment 1 of this invention, Fig.1 (a) is the front view, FIG.1 (b) is a side view, FIG.1 (c) is a bottom view. It is a figure which shows the external shape of the surface mount thin capacitor by Embodiment 2 of this invention, Fig.2 (a) is the front view, FIG.2 (b) is a side view, FIG.2 (c) is a bottom view. The external appearance of the surface mount thin capacitor of a prior art example is shown, Fig.3 (a) is the front view, FIG.3 (b) is a side view, FIG.3 (c) is a bottom view.

Explanation of symbols

1 Cover 1a Convex part 2 Case 3 Anode terminal 4 Cathode terminal

Claims (4)

  Capacitor element with oxide film formed on the surface of anode body made of expanded foil-like valve metal as dielectric layer and conductive functional polymer as solid electrolyte layer, electrode for surface mounting on the bottom A surface-mounting thin-film capacitor housed in an outer case having terminals formed thereon, wherein the side surface portion of the outer case is provided with a plurality of convex portions projecting downward from the mounting surface of the electrode terminal. Thin capacitor.   The outer case is composed of a main body case that is open on the upper side and an outer case that covers the upper side and the side of the main body case, and is protruded downward from the mounting surface of the electrode terminal on the side surface of the outer case. 2. The surface mount thin capacitor according to claim 1, wherein a portion is provided.   3. The surface mount thin capacitor according to claim 2, wherein the convex portion is provided at a corner of the bottom surface of the outer case.   3. The surface mount thin capacitor according to claim 2, wherein the convex portion is provided along the opposite side of the bottom surface of the exterior case.

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