JP4354240B2 - Surface mount type capacitors - Google Patents

Description

  The present invention relates to a surface-mount capacitor, and more particularly to a surface-mount capacitor that is downsized.

Conventionally, in order to reduce the height with a capacitor, as shown in FIG. 4, an aluminum case 11 is used for the exterior, and an L-shaped lead 12 led out from a sealing portion so as to be mounted horizontally on a printed circuit board. Therefore, it was soldered to the printed circuit board 13 (see, for example, Non-Patent Document 1).
In addition, a capacitor in which a multilayer capacitor element is enclosed in a laminate case has also been proposed (see, for example, Patent Document 1).
“'94 ELECTRONIC COMPONENTS”, Nichicon Corporation, October 1993, P.I. 114 JP 2002-75789 A

However, in the capacitor 10 using the aluminum case 11 for the exterior, the lead-out lead 12 led out from the sealing portion is bent into an L shape and soldered to the printed circuit board 13, and the electrolytic capacitor is fixed horizontally. The part where the lead was bent was an extra space.
Furthermore, since the lead is inserted into the lead hole of the board and soldered on the back surface of the board on which the capacitor is mounted, there is a problem that the height of the capacitor is high (the board thickness after mounting the capacitor is large).

  Further, in the capacitor 10 using the aluminum case 11 for the exterior, the sealing rubber 15 is used in order to keep the airtightness of the sealing portion. However, a certain amount of thickness is required to maintain the airtightness, and the exterior aluminum The volume occupying ratio with respect to the case 11 is large, and there is a problem that the outer dimension becomes large in order to obtain a predetermined capacitance.

  Furthermore, as shown in FIG. 5, instead of the lead-out lead type, a self-supporting type that fixed the capacitor with a large diameter and a low height perpendicular to the printed circuit board was also used. Since it was placed vertically, it was not possible to realize a sufficiently low profile.

  In addition, in order to reduce the outer dimensions, a method of reducing the thickness of the sealing rubber 15 used in the sealing portion has been studied, but there has been a problem that the lifetime is reduced due to a decrease in airtightness.

  On the other hand, a capacitor externally covered with a laminate case needs to have lead wire terminals inserted into a printed board and soldered, and the laminate case needs to be separately fixed to the printed board.

  Due to the above-described problems, there has been a demand for a capacitor that does not impair the low profile, does not increase the outer dimensions, and has a small space occupied by the lead lead terminals and can be surface mounted.

The present invention is intended to solve the above problem, as shown in FIGS. 1-3, have a drawn lead 34, the external connection terminal 32 with the capacitor element 1 which is sheathed with a laminate film 31, a welding margin on the back side The capacitor element 1 covered with the laminate film 31 is mounted on the fixed plate 33, and the seal portion bottom side 35 of the laminate film 31 is fixed to the fixed plate 33 and laminated. The surface mount type capacitor is characterized in that the lead lead 34 led out from the seal portion terminal side 36 of the film 31 is bent and fixed to the welding allowance of the external connection terminal 32 .

  The laminate film has a thickness of 20 to 200 μm.

  According to the present invention, it is possible to reduce the height of a surface mount capacitor and to provide a form with a small board occupation space.

As shown in FIGS. 1 to 3, a laminate film 31 is packaged on the capacitor element 1 and attached on a resin fixing plate 33.
An external connection terminal 32 is integrally formed on the fixed plate 33, and the lead lead 34 led out from the capacitor element 1 can be directly connected to the external connection terminal 32 of the fixed plate 33.

An embodiment according to the present invention will be described with reference to FIGS. As shown in FIG. 3, the capacitor element 1 is wrapped with a laminate film 31 having a thickness of 20 to 200 μm, and a heat seal allowance 42 is thermally welded and sealed, and mounted on a fixed plate 33 made of an insulating resin.
The welding allowance 41 on the seal portion bottom side 35 of the laminate film 31 is fixed to the fixing plate 33 by ultrasonic welding. At this time, if fixing by welding is difficult depending on the material, it is fixed using an adhesive or the like.
After the laminate film 31 and the fixing plate 33 are bonded, the lead 34 led out from the seal portion terminal side 36 is bent as shown in FIG. It is contacted and fixed by a welding method such as ultrasonic welding (or spot welding, laser welding) or the like that can obtain a metal bond.

  A conventional low profile aluminum electrolytic capacitor and a surface mount type (surface mount type) capacitor according to the present invention were compared in size at the same rating.

  The capacitor according to the above embodiment is reduced in height, occupied area, and volume as compared with the conventional example, and can reduce the mounting height and mounting area on the printed circuit board. Miniaturization is possible.

In addition, the range of 20-200 micrometers is suitable for the thickness of the said laminate film. If it is less than 20 μm, there is a problem that the tensile strength becomes weak, and if it exceeds 200 μm, there is a problem in bending and bonding work.
Further, since the fixing plate is provided with the external connection terminals, it is possible to perform soldering and fixing with the external connection terminals during surface mounting, and it is not necessary to fix the capacitor body to the substrate with an adhesive.
Furthermore, the capacitor element is effective not only in a wound type but also in a laminated type.
In addition, the sealing structure of the laminate is not limited to the embodiment, and a known method such as bending and sealing one laminate film to the lead terminal side and sealing with two laminate sheets is used. Can do.

1 is a perspective view of a surface mount capacitor according to an embodiment of the present invention. It is the perspective view which looked at the surface mount type capacitor of FIG. 1 from the bottom side. FIG. 2 is an assembly diagram of the surface mount capacitor of FIG. 1. It is a perspective view of the state which mounted the low-profile capacitor by the prior art example on the board | substrate. It is the perspective view which looked at the board self-supporting capacitor by other conventional examples from the bottom side.

Explanation of symbols

1 Capacitor Element 10 Surface Mount Capacitor 11 Aluminum Case 12 Lead Lead 13 Printed Circuit Board 14 Soldering Location 15 Sealing Rubber 16 Outer Sleeve 20 Substrate Standing Capacitor 21 Terminal 30 Surface Mount Capacitor 31 Laminate Film 32 External Connection Terminal 33 Fixing Plate 34 Lead lead 35 Seal part bottom side 36 Seal part terminal side 41 Welding allowance 42 Heat seal allowance 43 Heat seal location

Claims (2)

Have a drawn lead, and a capacitor element which is sheathed with a laminate film,
A fixing plate having an external connection terminal having a welding allowance on the back side ;
With
A capacitor element externally mounted with the laminate film is mounted on the fixing plate, and a bottom side of the seal portion of the laminate film is fixed to the fixing plate, and the lead lead led out from the seal portion terminal side of the laminate film A surface mount type capacitor, wherein the capacitor is bent and fixed to a welding allowance of the external connection terminal .   2. The surface mount capacitor according to claim 1, wherein the laminate film has a thickness of 20 to 200 [mu] m.

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