JPH04240705A - Chip-type capacitor and method for mounting the same - Google Patents

Abstract

PURPOSE:To realize a high-density surface mounting of a capacitor to a printed board without changing the ordinary structure of the capacitor. CONSTITUTION:A capacitor 1 is housed in an outer packaging frame 2 which has a housing space 4 fit for the outer shape of the capacitor 1 that has an adhesion layer 7 made chiefly of thermosetting resin in a part of the bottom face, and leads 3 led out from the end face of the capacitor 1 are bent along the opening end face and then along the bottom face of the outer packaging frame 2. As for the method for mounting such a chip-type capacitor 20, the capacitor 20 is mounted on a printed board 10 first and then is heat-treated to be secured to the printed board 10.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to improvements in capacitors, and more particularly to chip-type capacitors suitable for surface mounting on printed circuit boards.

0002

2. Description of the Related Art Conventional capacitors, particularly electrolytic capacitors, have a capacitor element housed in a cylindrical outer case with a bottom, the opening of which is sealed with a sealing member. Several attempts have been made to make such capacitors compatible with surface mounting on printed circuit boards. For example, a vertical type in which an insulating plate with a through hole is provided on the end face of the capacitor body and the lead wire of the capacitor body is bent from the through hole in the insulating plate along the bottom surface (Japanese Patent Application Laid-open No. 59-211214), or There were horizontal types in which the capacitor body was stored in the storage space of an exterior case made of resin etc., and the lead wires were bent on the same plane as the printed circuit board (Jikko Sho 59-355).
No. 7). According to these proposals, surface mounting on a printed circuit board becomes possible without changing the structure of a normal capacitor.

0003

[Problems to be Solved by the Invention] However, in the case of vertical chip capacitors, the lead wires are bent toward both ends of the insulating plate. If there was a time lag in the melting of the solder attached to the lead wires, the main body could be lifted due to an imbalance in surface tension. In addition, in the case of horizontal chip capacitors, the lead wires are led out only to one end face of the outer frame, so the main body may rise from the other end face due to soldering heat, buoyancy of melted solder, etc. Ta.

[0004] As a means to eliminate these inconveniences,
One possibility is to apply an adhesive onto the printed circuit board. However, in addition to requiring an extra step to apply the adhesive onto the printed circuit board, the soldering heat during the soldering process causes the adhesive to lose its adhesion on the printed circuit board, resulting in the same inconvenience as before. There were times when I ended up. Furthermore, due to the adhesive's viscosity, it is difficult to manage the amount of adhesive applied, and excess adhesive sometimes protrudes from the side of the mounted component.

[0005] Therefore, attempts have been made to, for example, provide a metal layer on the bottom surface of the exterior frame and solder it as an auxiliary terminal (Japanese Patent Laid-Open No. 1-227413). According to this proposal,
Because it is soldered at least at both ends of the exterior frame,
It is possible to prevent the main unit from standing up.

However, when the metal layer serving as the auxiliary terminal is attached to the outer frame, the number of parts to be soldered increases, making the mounting process on the printed circuit board complicated. Furthermore, as electronic devices become smaller and lighter, the density of wiring patterns on printed circuit boards increases, and efficient layout is required. Therefore, for horizontal chip capacitors that occupy a large area on the printed circuit board, it may be possible to provide a wiring pattern under the outer frame.
There is a risk that this wiring pattern and the metal layer of the exterior frame may be short-circuited.

The object of the present invention is to realize high-density surface mounting on a printed circuit board without changing the structure of an ordinary capacitor, and to strengthen the connection state.

[0008]

[Means for Solving the Problems] The present invention has a storage space that matches the external shape of the capacitor, and stores the capacitor in an exterior frame that has an adhesive layer mainly made of thermosetting resin on a part of the bottom surface. However, it is characterized in that the lead wire led out from the end face of the capacitor is bent along the open end face and bottom face of the exterior frame. Moreover, the method for mounting such a chip-type capacitor is characterized by mounting it on a printed circuit board and then subjecting it to heat treatment to fix it to the printed circuit board.

[0009]

[Operation] As shown in the drawings, the lead wire 3 led out from the capacitor 1 and the adhesive layer 7 mainly made of thermosetting resin are arranged on the bottom surface of the exterior frame 2. When mounting on the printed circuit board 10, the adhesive layer 7 is solidified and fixed to the printed circuit board 10 by heat treatment. Heat treatment is performed by heating in a reflow oven, and soldering is also performed at approximately the same time. Thermosetting resins are generally cured into an insoluble and infusible state by heat treatment. Therefore, the adhesive layer 7 is not thermally melted in this soldering process and in the subsequent usage environment, and can maintain a strong fixed state.

Furthermore, since there is no conductive auxiliary terminal etc. on the bottom surface of the exterior frame 2, and there is no conductive material other than the lead wire 3,
It becomes possible to form a wiring pattern on the printed circuit board within a range that does not short-circuit with the lead wire 3.

[0011]

Embodiments Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view of a chip-type capacitor according to an embodiment of the present invention, viewed from the bottom of the outer frame, and FIG. 2 is a perspective view of the outer frame used in this embodiment. Further, FIG. 3 is a front view showing a state in which a chip type capacitor according to an embodiment of the present invention is mounted on a printed circuit board.

The main body of the capacitor 1 is formed by housing a capacitor element formed by winding electrode foil and electrolytic paper (not shown) in a bottomed cylindrical outer case made of aluminum or the like. Then, the open end of the outer case is sealed with a sealing body, and the lead wire 3 led from the capacitor element is passed through the sealing body and drawn out to the outside.

The main body of the capacitor 1 includes an exterior frame 2 having a storage space 4 therein which is adapted to the outer diameter and shape of the capacitor 1, as shown in FIG.
Store it in. The exterior frame 2 is desirably made of a material with excellent heat resistance, preferably epoxy, which has excellent heat resistance.
Heat-resistant synthetic resins such as phenol and polyimide, ceramic materials, etc. are suitable.

The storage space 4 of the exterior frame 2 is formed into a cylindrical shape with an inner diameter that is approximately the same as the outer diameter of the capacitor 1, since this embodiment uses a capacitor 1 that has a cylindrical external shape. There is. However, non-cylindrical capacitors,
For example, when using a capacitor having an elliptical cross-sectional shape, an exterior frame having an elliptical cylindrical storage space that matches the shape is used.

A protrusion 5 is provided on one end face of the exterior frame 2 to cover a portion of the opening. This protrusion 5 comes into contact with the end surface of the capacitor 1 housed in the housing space 4 of the exterior frame 2. The main body of the capacitor 1 is housed in the storage space 4 of the exterior frame 2, and is fixed within the exterior frame 2 by the protrusion 5 and the bendable lead wire 3.

An adhesive layer 7 is formed on the bottom surface of the exterior frame 2, as shown in FIG. This adhesive layer 7 is made of a film mainly made of thermosetting resin, such as epoxy resin.
It is formed by bonding at a heating temperature of 00 to 150°C.

Alternatively, polyethylene terephthalate,
A so-called prepreg film, which is a base material made of polyester or the like coated with an epoxy resin, may be attached to the exterior frame 2. When attaching this prepreg film to the exterior frame 2, applying a pressure of about 1 to 10 kg/cm2 will improve the adhesion state. Furthermore, the epoxy resin can be applied directly to the exterior frame 2.
The epoxy resin may be applied to the bottom surface of the epoxy resin and subjected to heat treatment to bring the applied epoxy resin into a semi-solidified state. When a film mainly composed of a thermosetting resin such as a prepreg film is heat-treated and attached, the adhesive layer 7 becomes a semi-solidified state and does not adhere to other members under normal conditions.

The lead wire 3 of the capacitor 1 housed in the storage space 4 of the exterior frame 2 is bent along the open end face and bottom face of the exterior frame 2, and is stored in the groove 6 provided on the bottom face of the exterior frame 2, as shown in the figure. A chip type capacitor 20 such as 1 is formed.

Chip type capacitor 20 according to this embodiment
Here, the adhesive layer 7 is formed on the bottom surface of the exterior frame 2 by simply pasting, for example, a film-like adhesive layer 7. Therefore,
There is no need for the process of attaching auxiliary terminals and the like to the exterior frame 2 or the capacitor body 1. Further, there is no conductor other than the lead wire 3 on the bottom surface of the exterior frame 2, so that a wiring pattern can be provided within the range that does not short-circuit with the lead wire 3 on the printed circuit board 10 on which this chip capacitor 20 is mounted. Become.

Next, the process of mounting the chip capacitor 20 according to this embodiment on the printed circuit board 10 will be explained. As described above, in the chip type capacitor 20 according to this embodiment, the lead wire 3 led out from the capacitor 1 body and the adhesive layer 7 are arranged on the bottom surface of the exterior frame 2.

Therefore, when this chip type capacitor 20 is mounted on a printed circuit board 10 as shown in FIG. 3 and subjected to heat treatment at 100 to 150° C. in a reflow oven, the adhesive layer 7 is solidified and fixed to the printed circuit board 10. . The specific means for this heat treatment is not particularly limited, and means such as blowing hot air and infrared irradiation may be used. Thereafter, the chip capacitor 20 is mounted on the printed circuit board 10 through a soldering process that is performed almost simultaneously.

Chip type capacitor 20 according to this embodiment
By the process of mounting the chip capacitor 20 and the printed circuit board 10 on the printed circuit board 10, the chip capacitor 20 and the printed circuit board 10 are fixed not only at the soldered portion of the lead wire 3 but also at the adhesive layer 7, thereby achieving a strong mounting state. can do. In addition, since the adhesive layer 7 is mainly made of thermosetting resin,
It does not melt due to soldering heat, etc., and can prevent the main body from lifting up even if an inconvenience occurs in the soldering state.

[0023]

Effects of the Invention As described above, the present invention has a storage space that matches the external shape of the capacitor, and a capacitor is mounted in an exterior frame that has an adhesive layer mainly made of thermosetting resin on a part of the bottom surface. The capacitor is stored and the lead wire led out from the end face of the capacitor is bent along the open end face and bottom face of the exterior frame, so when mounted on a printed circuit board and soldered by reflow etc., the adhesive layer hardens. and is fixed to the printed circuit board. Therefore, it is possible to prevent the main body from floating up due to, for example, the buoyancy of molten solder.

Furthermore, since no conductor other than the lead wires of the capacitor body is placed on the bottom of the exterior frame, it is possible to provide a wiring pattern at the bottom of the chip-type capacitor according to the present invention, and it is possible to attach the wiring pattern to the printed circuit board. High-density mounting becomes easier.

Furthermore, since the chip-type capacitor and the printed circuit board are fixed together by a heat-resistant adhesive layer in addition to the soldered portion, it is possible to achieve and maintain a mounting state with excellent vibration resistance and heat resistance. and improve reliability.

The present invention is also characterized in that after the chip-type capacitor is mounted on a printed circuit board, it is fixed to the printed circuit board by heat treatment. This heat treatment can be performed almost simultaneously with soldering inside a reflow oven in the soldering process, so there is no need to apply an adhesive or the like to the printed circuit board in advance, which simplifies the process. Further, the adhesive layer solidified by heat treatment will not melt due to soldering heat, etc., and soldering can be performed reliably.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a chip capacitor according to an embodiment of the present invention, viewed from the bottom of an exterior frame.

FIG. 2 is a perspective view showing an exterior frame used in this embodiment.

FIG. 3 is a front view showing a state in which a chip capacitor according to an embodiment of the present invention is mounted on a printed circuit board.

[Explanation of symbols]

1 Capacitor 2 Exterior frame 3 Lead wire 4. Storage space 5 Protrusion 6 Groove 7 Adhesive layer 10 Printed circuit board 11 Solder 20 Chip type capacitor

Claims (2)

[Claims] Claim 1: The capacitor is housed in an exterior frame that has a storage space that matches the external shape of the capacitor and that has an adhesive layer mainly made of thermosetting resin on a part of the bottom surface,
A chip-type capacitor in which the lead wire led out from the end of the capacitor is bent along the open end and bottom of the outer frame. 2. A method for mounting a chip-type capacitor, in which the chip-type capacitor according to claim 1 is mounted on a printed circuit board and then subjected to heat treatment to be fixed to the printed circuit board.