JPS6230720B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method of mounting an electronic circuit board that effectively utilizes the space of the electronic circuit board to perform high-density mounting.

Conventional configurations and their problems In recent years, there has been an increasing demand for smaller and lighter electronic devices such as video tape recorders, and as a result, the electronic circuit boards that make up these devices have become more dense. is becoming an important issue.

Various methods have been used to increase the density of electronic circuit boards, but a typical method is to create blocks of circuits and modularize the circuit blocks. There is a method of configuring an electronic circuit by mounting it together with other circuit elements on a mother printed board.

This circuit block body is also called a hybrid integrated circuit component, and its structure is as shown in FIG. On the board, capacitors, transistors, and semiconductors are installed as circuit elements 4 necessary to configure the block circuit.
It is a high-density integration of ICs and the like, and lead wires 5 and 5' are soldered to both ends as external connection terminals. In order to attach such a circuit block body to the mother printed circuit board, as shown in FIG.
Then, the lead wires 5, 5' of the circuit block body are inserted and soldered.

However, in this method of mounting a circuit block body, the circuit block body and the mother printed circuit board are connected via lead wires, which makes the work of attaching the lead wires to the circuit block body complicated, as well as the connection between the lead wires and the circuit. The solder connection with the circuit block tends to be unstable, and when other circuit elements are mounted in the space between the circuit block and the mother printed circuit board, the higher the height of the circuit element, the longer the lead wire. This resulted in disadvantages such as loss of space on the mother printed circuit board, which hindered the construction of high-density electronic circuits.

Purpose of the Invention The present invention completely eliminates the above-mentioned drawbacks of the conventional example, enables effective use of space on the mother printed circuit board, and provides excellent connection reliability between the circuit block body and the mother printed circuit board. A method for mounting an electronic circuit board is provided.

Structure of the Invention The mounting method of the present invention includes forming a wiring circuit conductor on one main surface of a flexible insulating substrate, and forming external connection terminals on a pair of opposing ends of the one main surface of the insulating substrate. A conductor layer is formed to constitute a flexible wiring board, and three sheets are placed on the main surface of the flexible wiring board on the side where no external connection terminals are provided so that the flexible wiring board can be bent into a U-shape. A hard reinforcing plate is adhered, circuit elements are mounted on the wiring circuit conductor surface of the flexible wiring board for electrical connection, and each external connection of the flexible wiring board is made by bending the flexible wiring board into a U-shape. The terminals are inserted into two slit holes drilled in the mother printed board, and each of the external connection terminals is soldered to the circuit conductor of the mother printed board.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the drawings.

3 and 4 show a perspective view and a sectional view of a circuit block body used in the present invention, and this circuit block body has a U-shaped flexible wiring board on the back side of a flexible wiring board 7. Three hard reinforcing plates 8 are attached with adhesive 9 so that they can be bent into
Circuit elements 10 necessary for forming a circuit block are mounted on a substrate having a structure bonded by a wafer, and these are electrically connected to a flexible wiring board 7 by solder 11. be. In this case, the flexible wiring board 7 uses a polyimide film as a heat-resistant and flexible insulating substrate 7', and has a circuit conductor 7a made of copper foil on one surface and a longitudinally opposite circuit conductor 7a. a conductor layer 7b serving as an external connection terminal along a pair of both end surfaces;
7b' is formed. In addition, for the hard reinforcing plate 8 bonded to the other side of the flexible wiring board 7, a synthetic resin insulating substrate such as a paper-phenol laminate or a glass epoxy laminate, or a metal substrate such as aluminum, copper, or iron is used. Then, these hard reinforcing plates are bonded to the flexible wiring board using an adhesive 9 such as a thermosetting adhesive sheet made of epoxy resin or polyurethane resin, or a heat-resistant adhesive tape. As the circuit elements 10 constituting the block circuit, chip resistors, capacitors, planar connection type transistors, and semiconductor ICs are used.

In the present invention, a circuit block body having the above-described structure is bent into a U-shape with the circuit elements facing upward, and a pair of opposing external connection terminals 7b and 7b' are bent as shown in FIG. Insert the external connection terminals 7b, 7b' into the two elongated slit holes 13, 13' drilled in the mother printed circuit board 12, respectively, and connect the external connection terminals 7b, 7b' to the circuit conductor 12a of the mother printed circuit board 12a and the solder 14 as shown in FIG. Rotate and connect. With this mounting method, the circuit block mounted on the mother printed circuit board has a mounting structure in which circuit elements are arranged not only on its flat surface but also on the vertical portions of the mother printed circuit board. The space on the mother printed circuit board can be used effectively, and the density of the electronic circuit board can be increased.As mentioned above, the mounting connection of the circuit block body to the mother printed circuit board can be made by using two long and narrow holes in the mother printed circuit board. Since the circuit block body is mounted by inserting a pair of external connection terminals into the slit holes, the circuit block body is held by the two external connection terminals inserted into the slit holes, and the flexible wiring of the circuit block body is Due to the spring elastic force of the bent part of the board, the circuit conductors of the mother printed circuit board and the external connection terminals of the circuit block body are kept in good contact and fixed, and then soldered at the same time as other electrical components with leads. During general soldering connections made by immersing in a bath,
The circuit block body allows stable and good solder connection without causing problems such as lifting, tilting, or falling off. Furthermore, since the mother printed board and the circuit block are directly connected by solder without using lead wires, the reliability of the connection is improved.

FIG. 7 shows a second embodiment of the mounting method according to the present invention, in which the above-mentioned first circuit block body is folded into a U-shape, and a second circuit block body having the same structure is used. On one surface of an insulating substrate 15' made of a flexible polyimide film, conductor layers 15b, 15b' serving as external connection terminals are arranged along a pair of opposing end surfaces of a circuit conductor 15a made of a copper foil. A rigid reinforcing plate 16 made of an insulating substrate such as a paper phenol laminate or a glass epoxy laminate, or a metal plate such as aluminum or copper is placed on the back side of the flexible wiring board 15 on which the flexible wiring board 15 is bent into a U-shape. Circuit elements 17, such as chip resistors, capacitors, flat-connection mini-mold transistors, and semiconductor ICs, which are necessary to construct the circuit block, are mounted on the board that is bonded with adhesive so that the circuit block can be assembled. The second circuit block body is mounted on the flexible wiring board and electrically connected to the flexible wiring board by solder 18, and the hard reinforcing plates 8, 16 of the first circuit block body and the second circuit block body are connected to each other. Fold it into a U-shape so that it touches each other,
Circuit elements are arranged on the front and back sides of the hard reinforcing plates 8 and 16, and two slit holes 20 are formed in the connecting terminals 7b, 15b and 7b', 15b' exposed to the outside and in the mother printed circuit board 19. ,20′
The circuit conductors 19a of the mother printed circuit board are connected by solder 21 to the circuit conductors 19a of the mother printed circuit board.

By adopting this mounting method, it is possible to make solder connections between the circuit block body and the mother printed circuit board on both sides of the circuit conductors of the mother printed circuit board. It becomes possible to use board space more effectively, and a high-density electronic circuit board can be realized.

Effects of the Invention As explained above, in the electronic circuit board mounting method according to the present invention, the circuit block body is mounted and connected to the mother printed board by inserting the circuit block body into two elongated slit holes drilled in the mother printed board. A pair of external connection terminals can be inserted and mounted, and solder connections can be made using the solder bath dipping method, which is a common soldering method, and the circuit block body will not cause problems such as lifting, tilting, or falling off. A stable and good solder connection can be obtained without any problems. In addition, since the mother printed circuit board and the circuit block are connected without using lead wires, the reliability of the connection is improved. Since the circuit configuration is also performed on the part vertically erected from the mother printed circuit board, the space of the mother printed circuit board can be used effectively, and there is an effect that a higher density electronic circuit board can be constructed than that of the conventional example.

[Brief explanation of the drawing]

1 and 2 are a perspective view and a sectional view for explaining a conventional method of mounting an electronic circuit board, and FIGS. 3 and 4 are a perspective view and a sectional view of a circuit block body used in the present invention. , FIG. 5 is a perspective view of a mother printed board used in the present invention, FIG. 6 is a cross-sectional view of a mounting structure of an electronic circuit board according to the present invention, and FIG. 7 is for explaining a second embodiment of the present invention. FIG. 3 is a cross-sectional view of the mounting structure of the electronic circuit board of FIG. 7, 15...Flexible wiring board, 7', 1
5'... Flexible insulating board, 7a, 15a... Wiring circuit conductor, 7b, 7b', 15b, 15b'... External connection terminal, 8, 16... Hard reinforcing plate, 9... Adhesive, 10 , 17...Circuit element, 11, 14, 1
8, 21... Solder, 12, 19... Mother printed board, 12a, 19a... Circuit conductor, 13,
13', 20, 20'...Slit holes.

Claims (1)

[Claims] 1. A wiring circuit conductor is formed on one main surface of a flexible never-green substrate, and a conductor layer serving as an external connection terminal is formed on a pair of opposite ends of one main surface of the above-mentioned never-green substrate. three hard reinforcing plates are glued to the main surface of the flexible wiring board on the side where no external connection terminals are provided so that the flexible wiring board can be bent into a U-shape; Circuit elements were mounted on the wiring circuit conductor surface of the flexible wiring board to electrically connect them, and the flexible wiring board was bent into a U-shape to open each external connection terminal of the flexible wiring board in the mother printed circuit board. A method for mounting an electronic circuit board, comprising inserting the external connection terminals into two slit holes and connecting each of the external connection terminals to a circuit conductor of the mother printed circuit board by soldering.