JPS582065Y2 - welding ribbon - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a welding ribbon used when repairing a disconnected portion of a conductor pattern on a printed wiring board.

2. Description of the Related Art Printed wiring boards have conventionally been used in electronic devices for communications and the like in order to efficiently mount components and conduct wiring between those components.

This printed wiring board is usually made by pasting copper foil on one or both sides of an insulating plate made of glass cloth impregnated with resin and hardened, and then forming a wiring pattern on the copper foil by photo-etching.

In such a printed wiring board, during the etching process of the copper foil, the portion that will become the pattern may be corroded due to poor adhesion of the photoresist, resulting in disconnection of the pattern.

To repair this broken wire, place a welding ribbon 3, which is longer than the broken wire 2 of pattern 1, on top of pattern 1 and apply current as shown by the arrow while pressing the welding head 4, as shown in Figure 1, to weld pattern 1 and The ribbon 3 is resistance welded at parts A and B.

Generally, a welding ribbon with a rectangular cross section is used.

Moreover, if the width is narrower than the pattern width, the current will concentrate during welding and the pattern will explode, so a width slightly larger than the pattern width is used.

However, if the width of the welding ribbon is wide, the reliability of welding decreases due to effects such as heat dissipation and welding current diffusion.

The present invention was devised to improve this drawback.

For this reason, the welding ribbon of the present invention is a welding ribbon used for repairing a disconnected part of a pattern on a printed wiring board, and is made by forming new curves at both ends of the conductor ribbon so as to be in close contact with the top and side surfaces of the pattern. It is characterized by:

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 2 shows a sectional view of the embodiment.

In the figure, 5 is the welding ribbon of this example, and 6 is indicated by a chain line.
is the cross section of the pattern.

Normally, this pattern 6 is etched from the surface during etching, so its cross section has a trapezoidal shape as shown in the figure.

Therefore, in this embodiment, along this trapezoid, both ends 7,
7' is bent.

As for the material of this welding ribbon, copper,
Kovar, constantan, etc. or those with gold plating are used.

The welding ribbon 5 of the present invention thus formed is placed so that its concave portion fits into the pattern 6 as shown in FIG. 3, and welded while being pressed by the welding head 8.

At this time, both ends 7.7' of the welding ribbon 5 have a pattern 6.
Since the weld is in close contact with the weld, heat dissipation from the weld is less than in the past.

This results in stabilization of welding.

Figure 4 shows a case in which the welding ribbon is bent and welded to the pattern at the same time.Protrusions 10 and 10' are provided at both ends of the welding head 9 as shown in the figure, and the welding ribbon 11 with a rectangular cross section is formed. By placing it on the pattern 6 and pressing the welding head 9 as shown in FIG. 4, both ends of the welding ribbon 11 can be bent and welded at the same time.

In this case as well, since both ends of the welding ribbon 11 are in close contact with the side surfaces of the pattern, heat dissipation is prevented and welding can be stabilized, as in the case described above.

As explained above, the welding ribbon of the present invention is shaped to cover the top and side surfaces of the wiring pattern, thereby preventing heat dissipation from the welding ribbon and making it possible to perform welding reliably.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram of a method for repairing a broken part of a wiring pattern, Fig. 2 is a sectional view of a welding ribbon according to an embodiment of the present invention, Fig. 3 is an explanatory diagram of its use, and Fig. 4 is a folding of the welding ribbon. FIG. 3 is an explanatory diagram showing a case where bending and welding are performed at the same time. 5.11...Welding ribbon, 6...Wiring pattern, 8°9...Welding head.

Claims (1)

[Scope of utility model registration request] A welding ribbon used for repairing a disconnected portion of a pattern on a printed wiring board, the welding ribbon being characterized in that both ends of the conductor ribbon are bent so as to come into close contact with the top and side surfaces of the pattern.