JP3351433B2 - Chip type electronic components - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in an electronic component, and more particularly to a chip-type electronic component suitable for surface mounting on a substrate.

[0002]

2. Description of the Related Art Conventionally, in order to realize a chip of an electronic component such as a capacitor, an electronic component element is subjected to resin molding, and a lead wire for external connection led out from a resin end face is bent along a resin side face. It was facing the wiring pattern of the printed circuit board.

[0003] Alternatively, as disclosed in Japanese Utility Model Publication No. 59-3557, for example, a conventional electronic component is housed in an exterior frame, and a lead wire is arranged substantially flush with an end face of the exterior frame. Proposed. Also, Japanese Patent Application Laid-Open
As in the inventions described in JP-A-245116 and JP-A-60-245115, a capacitor is arranged on a bottomed cylindrical outer frame, and a lead wire is led out from a through hole at the bottom surface of the outer frame. A wire is proposed which is bent so as to be accommodated in a concave portion provided on the outer surface of an outer frame.

[0004]

However, in a chip-type electronic component to be molded, there is a possibility that the electronic component element is thermally degraded due to thermal stress during molding.

[0005] As shown in FIG. 3, a chip-type electronic component 22 in which an electronic component main body is housed in an exterior frame 2, a lead wire 3 is led out from an end surface of the exterior frame 2, and faces a printed board 10. When soldering 11 is applied, this chip-type electronic component 2
2 is fixed to the printed circuit board 10 by soldering 11 only at one end of the chip-type electronic component 22. Therefore, the so-called tombstone phenomenon occurs in which the other end is lifted by the surface tension of the molten solder and the heat of the solder, or the solder is separated from the printed circuit board 10 by mechanical stress.

[0006] Further, with the recent miniaturization of electronic components, the distance between lead wires derived from the electronic components has become extremely short, and this dimension has also become fine. Furthermore, the wiring pattern density of a printed circuit board has also increased, and the distance between various lead wires has been required for efficient placement. Therefore, it is necessary to secure an appropriate distance between the lead wires, that is, a distance that does not cause a short circuit due to solder, and to hold the lead wires so as to correspond to the distance between various lead wires. Has become.

Furthermore, the leading end of the lead wire facing the bottom surface of the outer frame attempts to restore its original shape by so-called "burrs" due to elastic force, and it has been difficult to maintain proper positions and distances. .

SUMMARY OF THE INVENTION An object of the present invention is to provide a chip-type electronic component capable of realizing a good mounting state on a printed circuit board without changing the structure of a normal electronic component.

[0009]

SUMMARY OF THE INVENTION According to the present invention, an electronic component is housed in an exterior frame having a storage space adapted to the external shape of the electronic component, and leads of the electronic component are placed along the opening end face and bottom surface of the exterior frame. In folded chip-type electronic components,
Form a solderable metal layer on a part of the surface of the exterior frame that has been subjected to corona discharge treatment to increase the polarity, and
Both ends are fixed to the printed circuit board by soldering .

[0010] Further, a solderable conductive paste or a solderable metal plate via an adhesive is attached as a solderable metal layer formed on the surface of the outer frame subjected to the corona discharge treatment. It is characterized by.

[0011]

As shown in the drawing, on the surface, particularly the bottom surface, of the exterior frame 2, a lead wire 3 derived from the electronic component body (capacitor) 1 and a solderable metal layer (conductive paste 7) are provided. Be placed. When mounted on a printed circuit board, the lead wire 3 and a metal layer (conductive paste 7) as auxiliary terminals are each soldered so that both ends of the bottom surface of the chip-type electronic component 20 are fixed to the printed circuit board by soldering. Will be done.

The metal layer (conductive paste 7) is formed on the surface 30 of the surface of the outer frame 2 that has been subjected to corona discharge treatment, that is, surface modification treatment. By this corona discharge, the molecular chains on the surface 30 of the outer frame 2 made of synthetic resin or the like are cut, and carbonyl groups, carboxyl groups, and the like are generated at the cut portions, the polarity of the surface 30 is increased, and the metal layer (conductive layer) is formed. The adhesion with the paste 7) is improved.

[0013]

Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view showing a chip-type electronic component according to an embodiment of the present invention from the bottom direction of an exterior frame, and FIG. 2 is a perspective view showing a second embodiment from the bottom direction of the exterior frame. In this embodiment, a capacitor will be described as an example of an electronic component.

The capacitor 1 as an electronic component body is formed by housing a capacitor element formed by winding an electrode foil (not shown) and electrolytic paper (not shown) in a bottomed cylindrical outer case made of aluminum or the like. Then, as shown in FIG. 1, a lead wire 3 led from the capacitor element is drawn out from the end face of the capacitor 1.

The capacitor 1 is housed in an exterior frame 2 having a cylindrical housing space 4 that matches the external shape of the capacitor 1 inside. It is desired that the exterior frame 2 be made of a material having excellent heat resistance. Preferably, a heat-resistant synthetic resin such as epoxy, phenol, or polyimide having excellent heat resistance is suitable.

In this embodiment, the storage space 4 of the exterior frame 2 is formed in a cylindrical shape having an inner diameter substantially the same as the outer diameter of the capacitor 1 because the external shape of the capacitor 1 is used in this embodiment. I have. When a non-cylindrical capacitor or another electronic component, for example, an electronic component having an elliptical cross-sectional shape is used, an exterior frame having an elliptical cylindrical storage space suitable for the shape is used.

The end face of the capacitor 1 housed in the housing space 4 of the exterior frame 2 abuts on a projection 5 formed on the opening end face of the exterior frame 2, and the end face of the capacitor 1 abutted on the projection 5 Are bent along the opening end surface and the bottom surface of the exterior frame 2 and housed in a groove 6 provided on the bottom surface of the exterior frame 2. Therefore, capacitor 1
The main body is fixed in the exterior frame 2 by the projections 5 and the bent lead wires 3.

A part of the bottom surface 3 of the outer frame 2
0 has been subjected to a surface modification treatment in advance. In this surface modification treatment, an output of 3 to 4 A is applied to the surface
The corona discharge was performed for 30 seconds.
Is activated. After the surface modification, the conductive paste 7 is applied to the surface 30 whose surface has been modified.

The conductive paste 7 is made of a solderable metal,
For example, metal particles of silver, tin, lead, zinc, nickel, iron, copper, or the like, or mixed particles of these, or metal particles made of an alloy thereof are mixed in a paste-like synthetic resin to be formed. Any kind of synthetic resin mixed with metal particles, that is, a binder may be used, but a thermosetting synthetic resin having excellent heat resistance, for example, epoxy, phenol,
Preferred are diallyl phthalate, unsaturated polyester, polyimide, polyamide imide, polyamide bismaleimide and the like.

In the case of this embodiment, the lead wire 3 led out from the main body of the capacitor 1 and the conductive paste 7 formed on a part of the surface 30 subjected to the surface modification treatment face the bottom surface of the exterior frame 2. . Therefore, when the chip-type electronic component 20 according to this embodiment is mounted on a printed circuit board, both ends of the chip-type electronic component 20 are fixed to the printed circuit board by soldering the lead wires 3 and the conductive paste 7, respectively. .

Twenty chip-type electronic components according to this embodiment and 20 chip-type electronic components not subjected to the surface modification treatment were prepared, and a conductive paste 7 in which copper particles were mixed in a binder of a phenolic resin was applied. When the adhesive strength of each sample was compared, the sample not subjected to the surface modification treatment had a maximum value of 4.35 Kgf, a minimum value of 0.51 Kgf and an average value of 2.16 Kgf. In the embodiment, the maximum is 7.91 Kgf and the minimum is 3.3.
At 0 Kgf, the average value was 5.66 Kgf, and the adhesive strength was significantly improved.

Next, a second embodiment of the present invention shown in FIG. 2 will be described. The capacitor 1, which is the electronic component body, is connected to the lead wire 3 from the end face of the capacitor 1 as in the first embodiment.
Is derived and formed. Similarly to the first embodiment, the exterior frame 2 has a storage space 4 for storing the capacitor 1 and a projection 5 on one end face of the opening. The lead wire 3 is bent from the end surface of the capacitor 1 along the bottom surface of the exterior frame 2 and faces the bottom surface of the exterior frame 2.

After the surface of the exterior frame 2 has been subjected to surface modification by corona discharge in the same manner as in the previous embodiment, an adhesive is applied to the portion subjected to the corona discharge treatment. The metal pieces 8 are arranged via an adhesive. Since the metal piece 8 is fixed by soldering when mounted on a printed circuit board, a solderable metal such as silver, tin,
Lead, zinc, nickel, iron, copper or alloys thereof are desirable. Alternatively, a metal tape in which an adhesive is applied to one surface of the solderable thin-film metal piece without applying the adhesive may be used.

The chip-type electronic component 21 according to this embodiment, like the first embodiment, is mounted on a printed circuit board, and then the lead wire 3 and the metal piece 8 are soldered.

In the embodiments of the present invention, a capacitor has been described as an example. However, the present invention can be applied to other electronic components as long as they can be accommodated in an outer frame. Needless to say.

[0026]

As described above, according to the present invention, an electronic component is housed in an exterior frame having a storage space adapted to the external shape of the electronic component, and leads of the electronic component are placed along the opening end face and the bottom surface of the exterior frame. in folded chip-type electronic part, the polarity of the surface subjected to a corona discharge treatment on a part of the surface of the outer frame
After applying the reforming to enhance the characteristics, it is characterized by forming a solderable metal layer on the part subjected to this corona discharge treatment, so when the lead wire facing the printed board and the metal layer are soldered, The chip-type electronic component according to the present invention is fixed to the printed board at both ends of the bottom surface of the outer frame. Therefore, it is possible to prevent the chip-type electronic component mounted on the printed board from being lifted up or separated from the printed board due to vibration, solder heat, "burr" of the lead wire, and the like as in the related art. In addition, it becomes stronger against mechanical stress when mounted on a printed circuit board, and can maintain a proper mounting state, thereby improving reliability.

Since a strong metal layer can be formed on the surface of the outer frame only by performing corona discharge treatment at a desired position, the manufacturing process is not complicated, and a large amount of surface Quality processing can be performed. Further, since the adhesive strength of the metal layer formed on the surface of the outer frame is improved, the metal layer does not peel off due to solder heat, vibration, and the like even in surface mounting on a printed circuit board, and the reliability is improved.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a chip-type electronic component according to an embodiment viewed from a bottom direction of an exterior frame.

FIG. 2 is a perspective view showing the second embodiment from the bottom direction of the exterior frame.

FIG. 3 is a front view showing a state in which a conventional chip-type electronic component is mounted on a printed circuit board.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electronic component main body (capacitor) 2 Exterior frame 3 Lead wire 4 Storage space 5 Projection part 6 Groove part 7 Conductive paste 8 Metal piece 10 Printed circuit board 11 Solder 20 Chip type electronic part 21 Chip type electronic part 22 Chip type electronic part

Claims (3)

(57) [Claims] An electronic component is housed in an exterior frame having a storage space adapted to the external shape of the electronic component, and a lead wire of the electronic component is bent along an opening end surface and a bottom surface of the exterior frame. Corona discharge treatment for polarity
Elevated the solderability metal layers formed on a part of the surface of the outer frame, pre by both ends are both soldered on the bottom of the outer frame
Chip-type electronic part fixed to a printed circuit board
Goods. 2. The chip-type electronic component according to claim 1, wherein a conductive paste that can be soldered is applied to a part of the surface of the exterior frame subjected to the corona discharge treatment. 3. The chip-type electronic component according to claim 1, wherein a metal plate that can be soldered via an adhesive is adhered to a part of the surface of the exterior frame subjected to the corona discharge treatment.