JPH0249738Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a structure for interconnecting printed wiring boards.

FIG. 1 is a sectional view for explaining the connection structure of the flexible printed wiring boards 1 and 6 according to the prior art, and FIG. 2 is the connection structure of the printed wiring boards 1 and 6 shown in FIG. 1. FIG. The printed wiring board 1 is composed of a pair of sheets 2 and 4 made of a flexible electrically insulating material, and a wiring section 3 made of copper foil printed between the sheets 2 and 4. Like the printed wiring board 1, the printed wiring board 6 is composed of sheet bodies 8, 10 and a wiring section 9. At the portion of the printed wiring board 1 to be connected, one of the sheet members 4 is removed in advance, and a connecting member 5 made of a conductive material having heat-sealing properties such as solder is fixed thereto. In the printed wiring board 6, a connecting member 7 such as solder is arranged at a position facing the connecting member 5. Those printed wiring boards 1 and 6 are heated at arrow 13 by a press machine 12 equipped with a heater 11.
It is heated and pressed in the direction of , via the presser plate 14 . As a result, the connecting members 5, 7 are melted to establish an electrical connection, the heat and pressure bonding is released, the connecting members 5, 7 are solidified again, and the printed wiring boards 1, 6 are fixed.

3 is a sectional view taken along the section line - in FIG. 2, and FIG. 4 is a sectional view taken along the section line - in FIG. 3. The wiring portion 3a and the wiring portion 3b shown in FIGS. 2 and 4 are collectively designated by the reference numeral 3, and the wiring portion 9a and the wiring portion 9b are collectively designated by the reference numeral 9. The wiring portion 3a of the printed wiring board 1 and the wiring portion 9a of the printed wiring board 6 are connected by the above-mentioned heat and pressure bonding, thereby forming a connecting portion 15a. During the heat compression bonding, the compression pressure is increased in order to efficiently transfer the heat from the heater 11 to the connecting members 5 and 7. Therefore, as shown in FIGS. 2 and 4, the molten connection members 5, 7 are spread from the portions of the connection members 5, 7 that are to be connected in the direction in which the wiring portions 3, 9 extend. It flows out to the left and right and is solidified, forming a bridge portion 16 on the surface of the sheet body 2 of the printed wiring board 1. When the wiring portion 3a and the wiring portion 3b are provided close to each other in this way, these wiring portions 3a, 3b,
9a and 9b may all be connected.
Further, when the printed wiring board 1 and the printed wiring board 6 are disposed so as to be shifted in the direction perpendicular to the wiring parts 3a and 3b of the printed wiring board 1 (in the vertical direction in FIG. 2), the wiring part 9a is shifted from the wiring part 3a. and wiring part 3b
or the wiring part 9b is connected to the wiring part 3.
There is a possibility that it may be connected to the wiring part 3b.

Furthermore, in the structure shown in FIG. 3, when bending stress is applied to the printed wiring boards 1 and 6, the force is
Both ends of 5a (connecting members 5, 7 and sheet bodies 4, 1
There was a problem that the connection was concentrated in the vicinity of the boundary with 0), and peeling was likely to occur at the connection portion 15a, resulting in low connection reliability.

The purpose of the present invention is to solve the problems of the prior art and to prevent erroneous connections such as short-circuiting of adjacent wiring parts due to the formation of bridge parts when connecting wiring parts of printed wiring boards to each other. It is an object of the present invention to provide a connection structure for a printed wiring board, which improves workability, prevents peeling of a connection part due to concentrated external stress, and improves connection reliability.

In the present invention, the exposed portion of the wiring portion of the first printed wiring board and the exposed portion of the wiring portion of the second printed wiring board are heated via a connecting member made of a conductive material having thermal fusion properties. A connection structure of printed wiring boards connected by fusion bonding, wherein the width of the wiring part of the second printed wiring board is:
The connecting member is fixed in advance to the entire surface of the exposed portion of the wiring portion, and the exposed portion of the wiring portion is formed to be larger than the width of the wiring portion of the first printed wiring board. This is a printed wiring board connection structure characterized in that the printed wiring boards are connected by heat fusion in a state where they are shifted in a direction away from the extending direction of the printed wiring boards.

FIG. 5 shows the flexibility of one embodiment of the present invention. 3 is a cross-sectional view for explaining a connection structure between a first printed wiring board 18 and a second printed wiring board 17. FIG. FIG. 6 is a plan view showing the connection structure of printed wiring boards 17 and 18 shown in FIG. 5. The second printed wiring board 17 includes a pair of sheet bodies 1 made of a flexible electrically insulating material.
9 and 21, and a second wiring section 20 made of a conductive material such as copper foil and printed between the sheets 19 and 21. At the part where the wiring part 20 of the second printed wiring board 17 is to be connected, one sheet body 21 protecting the wiring part 20 is removed in advance, and the second wiring part 20 from which this sheet body 21 is removed is A connecting member 22 is fixed to the exposed portion. The connecting member 22 is made of an electrically conductive material having heat-sealing properties, such as solder.

Like the second printed wiring board 17, the first printed wiring board 18 includes a sheet body 23 and a first sheet body 25, and a connecting member 26 is fixed to a portion of the printed wiring board 18 to be connected. has been done. The width W2 of the second wiring section 20 of the second printed wiring board 17 is formed larger than the width W1 of the first wiring section 24 of the first printed wiring board 18. Further, the connecting member 22 of the second printed wiring board 17 and the connecting member 26 of the first printed wiring board 18 are spaced apart from each other with respect to the extending direction of the wiring portions 20 and 24 (the left-right direction in FIG. 5). distance D in the direction
They are placed opposite each other in a shifted position. Those printed wiring boards 17 and printed wiring boards 18
is heated and pressed in the direction of arrow 13 via a presser plate 14 by a press machine 12 equipped with a heater 11 . As a result, printed wiring board 17 and printed wiring board 18 are fixedly attached. At the time of the heat compression bonding, as shown in FIG.
is arranged below the first printed wiring board 18 (lower side in FIG. 5).

7 is a sectional view taken along the cutting plane line - of FIG. 6, and FIG. 8 is a sectional view taken from the cutting plane line - of FIG. The wiring portion 20a and the wiring portion 20b shown in FIGS. 6 and 8 are collectively referred to as 2.
0, and the wiring portion 24a and the wiring portion 24b are collectively referred to as a reference numeral 24. In order to efficiently transfer the heat from the heater 11 to the connecting members 22 and 26 during the heat compression bonding, the compression pressure is increased. As described above, the connection member 22 and the connection member 26 are provided with a distance D between them, and the second
The width of the second wiring section 20 of the printed wiring board 17 of
W2 is formed large. As a result, although the connecting members 22 and 26 are melted during heat and pressure bonding, the melted connecting members 22 and 26 flow in the extending direction of the wiring portions 20 and 24 and are absorbed in the space D. Therefore, unlike the prior art, the wires do not flow out from the portions to be connected to the left and right with respect to the extending direction of the wiring portions 20 and 24. This results in the second
The wiring section 20b is electrically connected to the first wiring section 24a via the connecting section 27b, and the second wiring section 20b is
0b is connected to the first wiring section 24b via the connection section 27b.
electrically connected to.

Further, during heat-press bonding, if the width W2 of the second wiring portions 20a, 20b of the second printed wiring board 17 is within the range, the wiring portions 24a, 24b of the first printed wiring board 18 are connected to the second wiring portions 24a, 24b of the second printed wiring board 17. Wiring parts 20a, 20
Even if the second wiring portions 20a, 2
The width W2 of 0b is the width of the first wiring portions 24a, 24b
Since it is formed larger than W1, the wiring part 2
Misconnections are even less likely to occur than when the width W1 of the wiring portions 4a, 24b is made the same as the width W2 of the wiring portions 20a, 20b.

Furthermore, in the structure shown in FIG. 7, the length of the connecting portion 27a is not only the length A of the opposing bonding surfaces of the wiring portions 20 and 24, but also 2·D (that is, A+2·D). Printed wiring board 17, 18
Even if a bending stress indicated by an arrow 28 is applied to the connecting portion 27a, the force is distributed and acts on the portion of the connecting portion 27a at the distance D, so that peeling of the connecting portion 27a is less likely to occur.

In this way, the connection between the second wiring section 20a and the first wiring section 24a, and the connection between the second wiring section 20b
Also, the reliability of the connection of the first wiring portion 24b is improved.

Further, as shown in FIG. 7, when the length A of the opposing joint surfaces with the wiring portions 20 and 24 is constant, the configuration in which the distance D is larger is better than the configuration in which the distance D is smaller. Connecting portion 27a and connecting portion 2
7b, since a sufficient amount of solder can be used for the connecting members 22 and 26, the printed wiring board 1
7 and the printed wiring board 18 become stronger.

In the above embodiment, the flexible printed wiring board 17 and the flexible printed wiring board 1
Although the connection with 8 has been described, as another embodiment of the present invention, the connection between a flexible printed wiring board and a rigid printed wiring board is also described.
It is possible to implement the invention.

As described above, according to the present invention, in addition to changing the pattern width of each wiring part, the connecting member is fixed in advance to the entire surface of the exposed part of the wiring part, and the exposed parts are heated while being shifted from each other in the extending direction of the wiring. By connecting by fusion bonding, the connecting member can be lengthened, for example, by (A+2・D) as shown in Fig. 7, and the connection strength of the wiring part can be made strong enough to withstand bending stress, etc. that acts on the board. In order to prevent the connecting member from bridging the adjacent connecting portion and short-circuiting the wiring during heat fusion, the melted connecting member is applied to the entire exposed portion of the connecting member at the misaligned portion. For example, the connection member melts by swelling as shown by reference marks 29 and 30 in FIG. The main purpose of this technology is to absorb and prevent erroneous connections caused by the bridge portion of the connecting member as in the prior art, and prevent the mutual wiring portions of the printed wiring board from occurring. It is possible to improve the workability of connecting the wires and to improve the reliability of the connection of the wiring portions.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view for explaining the connection structure of the printed wiring boards 1 and 6 having the flexibility of advanced technology, and Fig. 2 shows the connection structure of the printed wiring boards 1 and 6 shown in Fig. 1. 3 is a sectional view taken from the cutting plane line - in FIG. 2, and FIG.
FIG. 5 is a sectional view taken from the cutting plane line - in the figure, and FIG. 5 shows a flexible wiring board 17 according to an embodiment of the present invention
6 is a plan view showing the connection structure of printed wiring boards 17 and 18 shown in FIG. 5, and FIG. FIG. 8 is a sectional view taken along the section line - in FIG. 7. 11...Heater, 12...Press machine, 17,1
8...Printed wiring board, 19, 21, 23, 2
5... Sheet body, 20, 24... Wiring part, 22,
26... Connection member, 27a, 27b... Connection part,
W1, W2... Width of wiring section, D... Spacing.

Claims (1)

[Claims for Utility Model Registration] A connecting member in which the exposed portion of the wiring portion of the first printed wiring board and the exposed portion of the wiring portion of the second printed wiring board are made of a conductive material having thermal fusion properties. A connection structure of printed wiring boards connected by heat fusion through a wiring board, wherein the width of the wiring part of the second printed wiring board is:
The connecting member is fixed in advance to the entire surface of the exposed portions of both wiring portions, and the exposed portions of both wiring portions are formed to be larger than the width of the wiring portions of the first printed wiring board. A connection structure for a printed wiring board, characterized in that the connection is made by heat fusion in a state where the parts are shifted in a direction in which they are separated from each other with respect to the extending direction of the parts.