JPS59112690A - Method of assembling electric circuit - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method of assembling an electric circuit using planar connection type electric circuit components and a flexible wiring board, which can be widely used in the manufacture of electric equipment. be.

2. Description of the Related Art Structures of Conventional Examples and Their Problems In recent years, flexible wiring boards have been widely used for the purpose of reducing the size and weight of electrical equipment and simplifying the equipment assembly process. For the same purpose, planar connection type electric circuit parts such as leadless type resistors, capacitors, coils called chip parts, transistors in ultra-small packages, guiatos, and ICs are used for the same purpose, and they are mounted and connected to wiring boards. The electrical circuit is assembled.

DESCRIPTION OF THE PREFERRED EMBODIMENTS A conventional method of assembling an electric circuit using a flexible wiring board and planar connection type electric circuit components will be described below with reference to the drawings. FIG. 1 is a cross-sectional view of an electric circuit assembled using a conventional flexible single-sided wiring board and planar connection type electric circuit components. /This "Ninkyo 11" ゛A planar connection type electrical circuit component 3 is mounted on the wiring conductor surface of a single-sided wiring board, and if necessary, an electrical circuit component 4 with a lead is mounted from the insulating film side, and the solder dip method is used. Soldering is performed from the wiring conductor surface using a method such as the above method to form the solder connection portion 5. This method has the advantage of lowering the total cost of the circuit because the wiring board is inexpensive and the circuit assembly process is simple, but the density of component mounting and wiring of the circuit is low, making the circuit smaller and lighter. There is a problem above. Therefore, as a way to increase the component mounting density and wiring density of the [L] path, through-hole conductors are formed.
There is also a method of assembling an electric circuit by using a two-sided board and mounting and connecting planar connection type electric circuit components on both sides of the board. FIG. 2 is a cross-sectional view of the electric circuit, in which wiring conductors 12 and through-hole conductors 16 are formed on both sides of an insulating film 110, and a cell 1/1/2 is formed on one side of a flexible double-sided wiring board. Equipped with 132L of electrical circuit parts of 11 connection type, half +1. R=J is performed to form a solder connection part 15a, a planar connection type electric circuit component 13b is mounted on the opposite side of the next wiring board, and soldering is performed again to form a solder connection part 15'b. can be obtained. This method has the advantage of making the circuit smaller and lighter by increasing the component mounting density of the circuit, but the flexible through-hole double-sided wiring board is about 3 to 5 times more expensive than the flexible single-sided wiring board. However, the assembly process is complicated because parts are repeatedly mounted and connected from both sides, and the overall cost is extremely high.

Purpose of the Invention The purpose of the present invention is to provide an inexpensive and extremely simple process.
An object of the present invention is to provide a method for assembling an electric circuit that can achieve high component mounting density and make it possible to reduce the size and weight of electric equipment.

Structure of the Invention The method for assembling an electric circuit of the present invention includes forming a wiring conductor on an insulating film, drilling a through hole at a desired position in a flexible wiring board, and then forming a through hole in at least one of the flexible wiring boards. The electrode part of a planar connection type circuit component is arranged on the surface so as to overlap with the through hole, and solder is supplied from the opposite surface to the surface on which the circuit component is arranged. This type of solder connection does not require the formation of through-hole conductors on the flexible wiring board, and it is possible to solder connect planar connection type circuit components mounted on both sides of the board at once by supplying solder from one side. It is something to do.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

FIG. 3 shows the flexible e-t used in the first embodiment of the invention.
+ It is a perspective view of a single-sided wiring board, in which a wiring conductor 22 is formed on an insulating film 21, and a through hole 27 is provided in a portion facing an electrode portion of a planar connection type circuit component to be described later. Polyimide film is used as the insulating film, but any material with sufficient soldering heat resistance, such as heat-resistant polyester, can be used.The thickness of the insulating film is 100 μm from the viewpoint of reliability of solder connection by soldering described later.
A good half-tone connection was obtained with a thickness of 26 μm. The shape and size of the through hole were provided to match the electrode portion of the circuit component. For example, 3.2 mm x 1, (3
In the case of a rectangular chip component with a diameter of 1.5 mW, two circular holes with a diameter of 1.5 mW were provided at an interval of 3.2 mm.

FIG. 4 is a perspective view of the flexible single-sided wiring board shown in FIG. After the circuit component 23b (not shown) is fixed with adhesive and mounted, the electrode part of the planar connection type circuit component 23& is superimposed on a part of the through hole 2 on the surface of the insulating film 21. Moreover, the through hole is mounted and fixed with adhesive so as not to be completely sealed.

FIG. 5 is a sectional view of the completed state according to the first embodiment of the present invention, and is a state obtained by performing soldering in the state shown in FIG. 4. Soldering is carried out using a general overflow type automatic soldering device by dipping the surface opposite to the surface on which the circuit components 23& shown in FIG. 4 are mounted (the surface on which the wiring conductor 22 is formed) into a solder bath. The electrode portion fd of the circuit component 23 & is soldered with the solder supplied through the through hole 27, and the wiring conductor and both ((+1
The circuit components mounted on the board were well connected by soldering, and the state shown in Fig. 5 was obtained. In the figure, 25 is a half loco connection. For soldering, in addition to the solder dipping method described above, solder paste is
It may also be done by a solder reflow method in which the circuit component 232L shown in the figure is applied to the surface opposite to the mounting surface by a dispenser method or screen printing method, and then heated solder paste is melted and soldered. 5 is a sectional view of a completed state according to a second embodiment of the present invention, and 31 to 37 in the figure are respectively 21 to 2 in FIG. 5.
It corresponds to γ.

In this embodiment, wiring conductors 3 are placed on both sides of the insulating film 310.
2 and a flexible double-sided wiring board provided with through holes 37 was used. The through hole was provided in a portion facing the electrode portion of the circuit component 33a to be mounted, as in the first embodiment. Planar connection type circuit components 33a and 33b are mounted and fixed on both sides of this flexible double-sided wiring board in the same manner as in the first embodiment, and the surface opposite to the mounting surface of the circuit component 33a is immersed in a solder bath. Half 1
-11 (=I) and the completed state shown in Figure 6 is TH.In this example, higher wiring density and higher component mounting density were obtained compared to the first example. According to the embodiment, it was possible to easily and inexpensively assemble an electric circuit having a double-sided wiring and double-sided component mounting structure without necessarily requiring the formation of a through-hole conductor on the inner wall of the through-hole.

Effects of the Invention As is clear from the above description, the present invention provides an arrangement in which the electrode portion of a planar connection type electrical circuit component is arranged so as to overlap a through hole drilled in a flexible wiring board, and Since solder is supplied from the opposite side of the circuit component to make a half []:I connection, circuit components can be mounted and connected on both sides of the board without the need to form through-hole conductors on the flexible wiring board. ,
It is still possible to make solder connections on both sides by soldering twice. Therefore, the present invention is a method of assembling an electric circuit that has an extremely simple process and inexpensive configuration, and provides high component mounting density and high wiring density, and has great industrial value6.

[Brief explanation of the drawing]

1 and 2 are cross-sectional views of a container for explaining a conventional method of assembling an electric circuit, and FIGS. 3, 4, and 5 are perspective views of a container for explaining a first embodiment of the present invention. FIG. 6 is a sectional view for explaining a second embodiment of the present invention. 1. 11. 21. 31... Insulating film, 2゜12, 22, 32 knee = - wiring conductor, 3.
13&. 13b, 23&, 23b, 33&, 33b..., Planar connection type electrical circuit parts, 4... Electric circuit parts with lead, 5.1sa, 161), 25.35.
... Half [11 connection part, 16 ... through-hole conductor, 27.37 ... through hole. Name of agent: Patent attorney Toshio Nakao and 1 other person 1st
Figure 4 Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] After forming a wiring conductor on an insulating film, a through hole is formed at a desired position of a flexible wiring board, and a 51' connection type circuit component is formed on at least one side of the flexible wiring board. A method for assembling an electric circuit, characterized in that an electrode portion is arranged so as to overlap with the through hole, and solder connection is made by supplying solder to the electrode portion from a surface opposite to the surface on which the circuit component is arranged.