JPH01227415A - Capacitor - Google Patents

Abstract

PURPOSE:To keep the space required for a capacitor to the minimum and to make such a capacitor as can be appropriately mounted on a printed board, by storing a capacitor element in an uncircular armoring case which has a solderable metallic layer on part of its flat face and by placing leads on almost the same face as that of the armoring case where the metallic layer is installed. CONSTITUTION:First, an uncircular armoring case 1 is prepared which has a pair of flat faces facing to each other, on one of which a solderable metallic layer 4 is installed partially. A capacitor element is stored in the armoring case and leads 3 are drawn out of the armoring case through a sealing material 2 and are placed on almost the same flat face as that of the armoring case where the metallic layer 4 is installed. The armoring case 1 is made of aluminum or other substance with a synthetic resin layer formed on its outer surface. As for the metallic layer 4, a metal piece 4 is adhered beforehand on part of the flat face of the armoring case 1 which comes into contact with a printed board. The leads 3 are bent from produced portions of the sealing material 2 along an end face of the armoring case, with their ends placed on almost the same flat face as that of the armoring case 1.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to improvements in capacitors, and particularly to capacitors suitable for surface mounting on printed circuit boards.

[Conventional technology]

Conventionally, to surface mount a capacitor on a printed circuit board,
The capacitor element was molded with resin, and lead wires for external connections were drawn out from the end of the resin and bent along the side of the resin to expose the printed circuit board.

Alternatively, it has been proposed, for example, as described in Japanese Utility Model Publication No. 59-3557, in which a conventional capacitor is housed in an exterior frame, and the lead wires are disposed approximately on the same plane as the end face of the exterior frame. . Also, JP-A-60-24511
As in the inventions described in Japanese Patent Publication No. 60-245115, a capacitor is arranged in a cylindrical outer frame with a bottom, and a lead wire is led out from a through hole at the bottom of the outer frame.
It has been proposed that this lead wire is bent so as to fit into a recess provided on the outer surface of the exterior frame.

Furthermore, as in the idea described in Japanese Utility Model Publication No. 55-50992, a device has been proposed in which a lead wire led out from a capacitor is bent and exposed to a printed circuit board for surface mounting.

[Problem to be solved by the invention]

However, in chip-type capacitors that are molded, there is a risk that the capacitor element may be thermally deteriorated due to thermal stress during molding, and the manufacturing process is also complicated.

In the case of chip-type capacitors, in which the capacitor is housed in an exterior frame and the lead wires are led out from the end face of the exterior frame and exposed to the printed circuit board, the number of parts increases and a process for housing the capacitor in the exterior frame is required. In addition, the occupied volume will also increase due to the exterior frame.

Furthermore, even if the lead wires are bent and the side surface of the capacitor body is brought into contact with the printed circuit board to support surface mounting, the prismatic space inscribed in the capacitor becomes a wasted space where other electronic components cannot be placed. . therefore,
This impedes the miniaturization of electronic devices, and also makes it difficult to stabilize it by mounting it on a printed circuit board.

Furthermore, as shown in FIG. 4, when the capacitor 11 with the lead wire 3 led out from one end is surface mounted, the capacitor 1 is fixed to the printed circuit board 7 by soldering.
Only one end of 1 is available. Therefore, the other end of the capacitor 11 may lift up due to soldering heat, or may separate from the printed circuit board 7 due to mechanical stress.

An object of the present invention is to provide a capacitor that minimizes the volume occupied and maintains a proper mounting state on a printed circuit board.

[Means to solve the problem]

This invention has a pair of opposing plane parts, and
The capacitor element is housed in a non-circular exterior case with a metal layer that can be soldered on a part of one flat surface, and the lead wires that pass through the sealing body and lead out to the outside are connected to the metal layer of the exterior case. It is characterized in that it is arranged almost on the same plane as the provided flat part.

Another method is to adhere a solderable metal piece to one flat surface of the outer case, apply a solderable conductive paste, or deposit a solderable metal layer. It is characterized by

[For production]

As shown in FIG. 1, one plane part of the outer case 1,
That is, a lead wire 3 led out from the capacitor 8 and a metal layer (metal piece 4) that can be soldered are arranged on a flat surface that comes into contact with the printed circuit board when mounted on the printed circuit board. When mounting on a printed circuit board, both ends of the capacitor 8 are fixed to the printed circuit board by soldering the lead wire 3 and the metal layer (metal piece 4), respectively.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view of a capacitor according to an embodiment of the present invention, viewed from the direction of the plane surface that contacts a printed circuit board, and FIG. 2 is a perspective view of a second embodiment. Moreover, FIG. 3 is a front view showing the third embodiment.

The capacitor element is formed into a non-circular shape by winding electrode foil and electrolytic paper (not shown). The lead wires 3 electrically connected to each electrode foil protrude from the end face of the capacitor element and penetrate the sealing body 2, as shown in FIG.

The exterior case 1 is made of aluminum or the like, and has an opening shape of
It is formed into an oval shape with a pair of opposing flat parts. The outer surface is coated with a synthetic resin to form a synthetic resin layer. The synthetic resin forming the synthetic resin layer is suitably one that has excellent heat resistance, and preferably one that can withstand soldering heat of 230° C. or higher. For example, epoxy, phenol, diallyl phthalate, polyimide, unsaturated polyester, polyamideimide, polyamino bismaleimide, polyphenylene sulfide, polyether sulfone, polyether ketone, polyether ether ketone, polyether imide, polyamide, polyallyl ether ketone, Examples include polyarylsulfone.

Although any method may be used to coat the synthetic resin layer, in this example, an aluminum plate coated with an epoxy resin was press-worked to form the outer case 1. This synthetic resin layer insulates the printed circuit board on which the capacitor 8 is mounted and the capacitor 8, and also insulates the lead wire 3 and the capacitor 8. Additionally, soldering protects the capacitor element from soldering heat during the process.

A metal piece 4 is bonded in advance to one plane part of the exterior case 1, that is, to a part of the plane part that comes into contact with the printed circuit board. Since this metal piece 4 is fixed by soldering when mounted on a printed circuit board, it is preferable to use a metal that can be soldered, such as silver, tin, lead, zinc, nickel, iron, copper, or an alloy thereof, or For soldering, a metal tape with an adhesive coated on one side of the thin metal piece may be used.

The exterior case 1 includes a capacitor element impregnated with an electrolyte,
and the sealing body 2 through which the lead wire 3 has passed are housed together,
Its open end is tightened to seal the interior.

A lead wire 3 penetrates the sealing body 2 and protrudes to the outside.
is bent along the end surface from the protruding portion of the sealing body 2, and furthermore, the tip portion 1 is disposed on substantially the same plane as the flat surface of the outer case l. Lead & 13 when bending
By holding a portion of the capacitor element with a holding jig, stress on the capacitor element can be reduced.

In the case of this embodiment, the lead wire 3 led out from the main body of the capacitor 8 and the metal piece 4 that can be soldered are arranged substantially on the same plane as one plane part of the outer case 1. Therefore, when the capacitor 8 according to this embodiment is mounted on a printed circuit board, both ends of the capacitor 8 that contact the printed circuit board are fixed by soldering the lead wire 3 and the metal piece 4, respectively.

Next, a second embodiment of the invention shown in FIG. 2 will be explained. The main body of the capacitor 9 is formed with lead wires 3 led out from the end face, as in the first embodiment. Further, the exterior case 1 also has a pair of opposing plane parts, similar to the first embodiment. A conductive paste 5 is applied to one plane part of the exterior case l, that is, the plane part that will come into contact with the printed circuit board when it is mounted on the printed circuit board.

This conductive paste 5 is made of a metal that can be soldered, such as metal powder such as silver, tin, lead, zinc, nickel, iron, copper, a mixed powder thereof, or a metal powder made of an alloy thereof, and a synthetic resin. It is mixed into and generated. The synthetic resin mixed with metal powder may be of any kind, but thermosetting synthetic resins with excellent heat resistance, such as epoxy, phenol, diallyl phthalate, unsaturated polyester, polyimide, polyamideimide, polyamide, etc. Bismaleimide and the like are preferred.

The capacitor 9 according to this embodiment is mounted on a printed circuit board, and then the lead wires 3 and the conductive paste 5 are soldered to each other, similarly to the first embodiment.

In the case of this embodiment, compared to the first embodiment, there is no need to use an adhesive or the like, and a metal layer that can be soldered to the outer case 1 can be easily generated. Furthermore, in soldering, there is no risk of thermal change or peeling of the adhesive due to soldering heat during the soldering process.

Next, a third embodiment shown in FIG. 3 will be described. In this embodiment, similarly to the first and second embodiments, the capacitor element is housed in an exterior case l having a pair of opposing flat parts, and the lead wire 3 led out from the capacitor 10 is connected to the capacitor lO. It is bent from the end face along one plane part. A vapor deposited layer 6 made of a solderable metal such as silver, tin, lead, zinc, nickel, iron, copper, etc. is formed in advance on a part of one plane of the exterior case 1.

In this embodiment, the metal pieces 4 are bonded together using an adhesive as in the first embodiment, or a conductive paste 5 made of synthetic resin mixed with metal powder or the like is applied as in the second embodiment. , the capacitor 10kJ1:lK11 (deposited layer 6) can be formed without considering the heat resistance of adhesives, synthetic resins, etc.

〔Effect of the invention〕

As described above, the present invention houses a capacitor element in a non-circular exterior case that has a pair of opposing flat parts and a metal layer that can be soldered on a part of one of the flat parts. The lead wires that pass through the board and lead out to the outside are arranged almost on the same plane as the flat part of the outer case where the metal layer is provided, so that the lead wires facing the printed circuit board and the metal piece or metal layer are not connected to each other. If you solder the
The capacitor is fixed at both ends of the contact surface with the pudding +-g board on which it is mounted. Therefore, it is possible to prevent a capacitor mounted on a printed circuit board from rising or detaching from the printed circuit board due to soldering heat, ``burrs'' of lead wires, etc., as in the conventional case.

Moreover, it becomes strong against mechanical stress when mounted on a printed circuit board, and a proper mounting state can be maintained, improving reliability.

Another method is to adhere a solderable metal piece to one flat surface of the outer case, apply a solderable conductive paste, or deposit a solderable metal layer. Because of this feature, an extremely thin metal layer that can be soldered is formed on a part of the bottom of the outer case. Therefore, the stability of the capacitor is not compromised.
In addition to being able to maintain a stable mounting state, the electronic components are not mounted diagonally during the mounting process, so they can be transported and mounted in the same way as electronic components used for normal surface mounting.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a capacitor according to an embodiment of the present invention, viewed from the direction of the plane surface that contacts a printed circuit board, and FIG. 2 is a perspective view of a second embodiment. Moreover, FIG. 3 is a front view showing the third embodiment. FIG. 4 is a front view showing a conventional capacitor mounted on a printed circuit board. l... Exterior case, 2... Sealing body, 3... Lead wire, 4... Metal piece, 5... Conductive paste, 6...
Vapor deposition layer, 7... printed circuit board.

Claims (4)

[Claims] (1) A capacitor element is housed in a non-circular exterior case that has a pair of opposing flat parts and a solderable metal layer on a part of one of the flat parts, and is passed through the sealing body and exposed to the outside. A capacitor characterized in that the led wires are arranged on substantially the same plane as a flat part of an outer case provided with a metal layer. (2) The capacitor according to claim 1, further comprising a solderable metal piece bonded to one flat surface of the exterior case. (3) The capacitor according to claim 1, wherein a solderable conductive paste is applied to one flat surface of the exterior case. (4) The capacitor according to claim 1, wherein a solderable metal layer is deposited on one flat surface of the outer case.