JP2002141660A - Method for connecting flexible printed board to each other - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for mutual connection between flexible printed boards which can reduce the manufacture cost by securely connecting terminals of the flexible printed boards to each other at low cost and suppressing a rise in the cost regarding the connection between the flexible printed boards. SOLUTION: Sheets, etc., constituting insulating films 15 and 25 as the bases of FPC's 10 and 20 are prepared and processed into a desired shape, etc. On the processed insulating films 15 and 25, wires 16 and 26 are formed and cover lays 17 and 27 are formed on the insulating films 17 and 27 and FPC's 10 and 20 except parts which become the terminal parts 11 and 21 to manufacture the FPC's 10 and 20. End surfaces 12 and 22 of the terminal parts 11 and 21 of the FPC's 10 and 20 thus manufactured are made to abut against each other to bring the wires 16 and 26 into contact with each other, and a conductive material 50 of copper foil is mounted across over those wires 16 and 26. Then electrodes 9a and 9b of a series welding device are made to abut against the top of the conductive material 50 on the terminals 11 and 21 in order, and series welding is carried out to join the conductive material 50 to the wires 16 and 26, so that the FPC's 10 and 20 are electrically and mechanically connected to each other.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of connecting flexible printed circuit boards, and more particularly, to a method of connecting terminals of flexible printed circuit boards inexpensively and reliably. Connection method.

[0002]

2. Description of the Related Art In recent years, wire harnesses used in automobiles and the like have been used as much as
There is a growing movement to substitute rinted circuits (FPC). By such a movement, for example, as shown in FIG.
In order to electrically connect the electronic control unit 301, the fuse box 302, and the like mounted inside the FPC 0, instead of the conventional circuit connection wire harness 500, an FPC is used.
400 will be used more.

When the FPC is used for such a purpose,
Generally, for example, an FPC that is much larger in size than an FPC used in home electric appliances will be used. Usually, the FPC is manufactured by punching out the outer shape with a die, and the size thereof is restricted to a predetermined size. However, the FPC is used instead of the conventional circuit connection wire harness 500 as shown in FIG. In such a case, an FPC having a size larger than the current production limit FPC is required.

In this case, as shown in FIG. 8, for example, several FPCs 401 to 404 manufactured separately are used.
And the FPC harnesses 405, 406 and the like are jointed to form one FPC 400 for use. Thus, the FPCs 401 to 404
FPC harness 4
05, 406, etc., using FPCs 401 to 404 and FPCs using a dedicated connector (not shown).
A method of connecting the PC harnesses 405 and 406 is generally performed. In addition, without using a special connector, FPC
In order to connect them, for example, a method of caulking or removing FPC terminals has been studied,
There are problems such as electrical connection reliability and durability, and it seems that it still takes time to put it into full practical use. Therefore, at this stage, it is necessary to rely on connection using a dedicated connection connector.

[0005]

However, in connection between FPCs by such a dedicated connector,
Since a dedicated connection connector (not shown) is required for each joint as shown in FIG. 8,
There is a problem that the cost for connecting the FPCs alone becomes enormous, which may increase the manufacturing cost of the in-vehicle FPC or the FPC harness. Also,
Even if such a connection method that does not use the dedicated connection connector is adopted, there is a problem that the connection reliability may be lacked because the connection technology has not yet been established, and it is difficult to adopt the connection method.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and inexpensively and securely connects terminals of a flexible printed circuit board, thereby increasing the cost of connecting the flexible printed circuit boards. It is an object of the present invention to provide a method for connecting flexible printed circuit boards, which can reduce the manufacturing cost.

[0007]

A method for connecting flexible printed circuit boards according to the present invention is a method for connecting flexible printed circuit boards each having a conductor wiring formed on an insulating film. The end faces of the respective terminal portions are abutted so that the conductor wiring of the terminal portion of the flexible printed circuit board and the conductor wiring of the terminal portion of the other flexible printed circuit board are continuous, and the abutment of the two terminal portions is performed. On both conductor wiring so as to straddle the part,
A thin or foil-shaped conductive material is placed, and positive and negative electrodes are brought into contact with the upper side of the above-described conductive material at each end to apply pressure in the thickness direction of the flexible printed circuit board. In addition, a predetermined voltage is applied between the abutted electrodes, and the conductive material and the conductor wiring at the both end portions are respectively joined by resistance welding.

Further, a method for connecting flexible printed boards according to the present invention is a method for connecting flexible printed boards formed by forming conductor wiring on an insulating film,
The end faces of the respective terminal portions are abutted so that the conductor wiring of the terminal portion of one flexible printed circuit board and the conductor wiring of the terminal portion of the other flexible printed circuit board are continuous with each other. A thin plate or foil-like conductive material is placed on the two conductor wirings via solder so as to straddle the abutting portion, and a soldering iron is brought into contact with the upper side of the placed conductive material, and this contact is made. The method is characterized in that the soldering iron is heated to melt the solder, and the conductive material at both ends and the conductor wiring are joined by soldering.

Further, the method for connecting flexible printed boards according to the present invention is a method for connecting flexible printed boards each having a conductor wiring formed on an insulating film,
The end faces of the respective terminal portions are abutted so that the conductor wiring of the terminal portion of one flexible printed circuit board and the conductor wiring of the terminal portion of the other flexible printed circuit board are continuous with each other. A thin plate or foil-shaped conductive material is placed on the two conductor wirings so as to straddle the abutting portion, and either one of the upper side of the conductive material described above and the lower side of the insulating film of each terminal portion. The horn and the anvil are abutted on the other, and an ultrasonic wave of a predetermined frequency is output between the abutted horn and the anvil to ultrasonically weld the conductive material and the conductor wiring of the both end portions. It is characterized by joining each.

The conductive material preferably has a thickness of 18 μm or more.
70 μm copper foil.

According to the present invention, the end surfaces of the terminal portions of the respective flexible printed circuit boards to be connected (hereinafter referred to as "FPC" only in this paragraph) are abutted so that the conductor wiring is continuous, and both of them are joined. A thin plate or foil-shaped conductive material is placed on each conductor wiring formed on both terminal portions so as to straddle the abutting portion of the terminal portion, and plus and over the conductive material placed on each terminal portion. A negative electrode is brought into contact with the electrode to apply pressure, a predetermined voltage is applied between the electrodes, and the conductive material and the conductor wiring at both ends are joined by resistance welding (for example, series welding) to form an FPC. Connect each other. Further, according to the present invention, the end faces of the terminal portions of the respective FPCs to be connected are abutted so that the conductor wiring is continuous, and each of the FPCs is formed on both the terminal portions so as to straddle the abutting portion of the two terminal portions. A thin plate or thin conductive material is placed on the conductor wiring of the above via a solder, a soldering iron is brought into contact with the upper side of the placed conductive material, and the soldered iron is heated and soldered. Is melted, and the conductive material and the conductor wiring at both ends are joined by soldering to connect the FPCs. Further, according to the present invention, the end faces of the terminal portions of the respective FPCs to be connected are abutted so that the conductor wiring is continuous, and the respective end portions formed on both the terminal portions so as to straddle the abutting portions of the two terminal portions. A conductive material in the form of a thin plate or foil is placed on the conductive wiring, and the horn is brought into contact with one of the upper side of the placed conductive material and the lower side of the insulating film in each terminal portion, and the anvil is brought into contact with the other. Then, ultrasonic waves having a predetermined frequency are output between the horn and the anvil, and the conductive material and the conductor wiring at both ends are joined by ultrasonic welding to connect the FPCs. This eliminates the need for components such as dedicated connection connectors, which have been required for the conventional electrical connection between FPCs, so that the cost for connection can be significantly reduced. Further, since the respective conductor wirings of the FPC are joined by, for example, resistance welding, soldering or ultrasonic welding, it is possible to obtain extremely high connection reliability as compared with the connection between FPCs using a dedicated connector or the like. Become.

[0012]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is an upper perspective view of a terminal portion for explaining a method of connecting flexible printed boards according to an embodiment of the present invention, and FIGS. 2 and 3 show a method of connecting flexible printed boards. FIG. 4 shows a top view and a cross section of a terminal section for explaining. FIG. 4 is a side view showing a part of the terminal section for explaining resistance welding, and FIG. 5 is a process of connecting flexible printed circuit boards. It is a flowchart which shows.

As shown in FIG. 1, FPCs 10 and 20 to be connected to each other are made of, for example, polyethylene terephthalate (PET) or polyethylene naphthalate (PEN).
Wirings 16 and 26 made of a conductive pattern made of copper foil are formed on resin films 15 and 25 having insulating properties (hereinafter referred to as “insulating films”) made of the same. A cover lay 17 made of a synthetic resin or the like having electrical insulation performance on
It is formed with a structure covered by 27. In addition, FPC1
Insulating films 15, 25 of terminal portions 11, 21 of 0, 20
The coverlays 17 and 2
7 are not formed, and the wires 16 and 26, which should have been originally covered by the coverlays 17 and 27, are exposed in the respective terminal portions 11 and 21.

Hereinafter, the FPC 1 thus formed will be described.
A connection method between 0 and 20 will be described. First, sheets and the like constituting insulating films 15 and 25 serving as bases of FPCs 10 and 20 composed of PET or PEN are prepared and processed into a desired shape or the like (S1). Next, on the processed insulating films 15 and 25, wirings 16 and 26 made of a conductive pattern made of Cu or the like constituting the circuits of the FPCs 10 and 20 are formed by patterning, for example, by etching or the like. Then, coverlays 17 and 27 are formed on the insulating films 15 and 25 and the wirings 16 and 26 except for the portions that will become the FPCs 10 and 20 (S2). The FPC 10 manufactured in this manner,
When the end faces 12 and 22 of the 20 terminals 11 and 21 abut against each other (S3) and the wirings 16 and 26 are brought into contact with each other, the terminals 11 and 21 are in a state as shown in FIG. That is,
As shown in FIG. 2B, the insulating films 15 and 25 of the terminal portions 11 and 21 and the wirings 16 and 26 are in contact with each other via the end faces 12 and 22, and the lower surfaces of the insulating films 15 and 25 and the wirings 16 and 26. 26 is in a state of forming the same continuous surface. Next, the conductive material 50 made of copper foil is placed so as to straddle the wirings 16 and 26 in contact with the terminals 11 and 21 (S4). At this time, the terminal units 11 and 21 are in a state as shown in FIG. That is, as shown in FIG. 3B, the upper surfaces of the wirings 16 and 26 of the terminal portions 11 and 21 and the lower surface of the conductive material 50 are in contact with each other. Terminal 1
After setting the electrodes 1 and 21 in such a state, as shown in FIG. 4A, first, for example, the electrodes 9a and 9b of a series welding device (not shown) are connected to the conductive material placed on the wiring 16. 50
A predetermined voltage is applied between the electrodes 9a and 9b so as to apply a large current having a capacity used for series welding while pressing the electrode 9a and 9b downward. Then, the copper of the wiring 16 and the conductive material 50 is mutually diffused into other layers by the thermal energy generated by energization and the pressing force by the electrodes 9a and 9b (diffusion welding), so that the wiring 16 and the conductive material 50 are formed. Welding is performed (S5). Next, as shown in FIG. 2B, the electrodes 9a and 9b are brought into contact with the upper side of the conductive material 50 placed on the wiring 26, and are similarly subjected to series welding while being pressed downward, thereby forming the FPC 20. The conductive material 50 on the terminal 21 side and the wiring 26 are welded and joined (S5), and the FPC 10 and the FPC 20
Are electrically and mechanically connected to each other. In this way FP
By connecting the C10 and the C20, it is possible to connect the FPCs which do not require a component such as a dedicated connection connector. Therefore, the cost of the connection between the FPCs is greatly reduced, and the FPC used for an automobile or the like is reduced. It is possible to suppress an increase in manufacturing cost.

In the above example, the FPCs 10, 20
Although the description has been made using the connection by resistance welding when connecting each other, for example, the connection by ultrasonic welding as shown in FIG. 6A or the connection by soldering as shown in FIG. good. Hereinafter, the connection method by ultrasonic welding and the connection method by soldering will be described. The parts already described in the connection method by resistance welding are omitted.

First, in the method of connecting FPCs by ultrasonic welding, the steps up to step S4 of the connection step are the same, but the subsequent steps are different. That is, wiring 1
After the conductive material 50 is placed on the conductive materials 50 and 6, 26, a horn 40 of an ultrasonic welding device (not shown) is applied to the conductive material 50 of the terminal portion 11, for example, as shown in FIG. The anvil 41 is brought into contact with the lower surface of the insulating film 15 at a position facing the horn 40, and the frequency is 60 KHz to 120 KH.
An ultrasonic wave of about z is output between the horn 40 and the anvil 41, and the conductive material 50 on the terminal portion 11 side of the FPC 10 and the wiring 16 are joined by ultrasonic welding. Horn 4 as well
0 and the anvil 41 are connected to the conductive material 50 of the terminal 21 and the wiring 2.
6 and is subjected to an ultrasonic welding process, and the conductive material 50 on the terminal portion 21 side of the FPC 20 and the wiring 26 are joined by ultrasonic welding to electrically and mechanically connect the FPC 10 and the FPC 20.

On the other hand, in the method of connecting FPCs by soldering, the steps up to step S3 of the connection step are the same, but the subsequent steps are different. That is, the terminal unit 1
After contacting the end faces 12 and 22 of the wirings 1 and 21,
First, the solder 51 is placed on the solder 26, and then the conductive material 50 is placed on the placed solder 51. After placing the conductive material 50, as shown in FIG. 6B, for example, the tip 53 of the soldering iron 52 is brought into contact with the conductive material 50 of the terminal portion 11,
The solder 51 is heated and melted via the conductive material 50, and the tip 53 of the soldering iron 52 is separated from the conductive material 50 to solidify the melted solder 51, thereby forming the conductive material 50 on the terminal 11 side of the FPC 10. And the wiring 16 are joined by soldering. Similarly, a soldering iron 5 is placed on the conductive material 50 of the terminal 21.
2 abuts on the tip 53, performs soldering processing, and
The FPC 10 and the FPC 20 are electrically and mechanically connected by joining the conductive material 50 on the terminal 21 side of the 20 and the wiring 26 by soldering.

In such a connection by ultrasonic welding or soldering, high connection reliability can be obtained as in the case of the connection by resistance welding, and an FPC that does not require components such as a dedicated connection connector. The connection between the FPCs can be performed, and the cost related to the connection between the FPCs can be significantly reduced.

[0019]

As described above, according to the present invention,
The end faces of the terminal portions of the respective FPCs to be connected are abutted so that the conductor wiring is continuous, and a thin plate or foil is placed on each conductor wiring formed on both the terminal portions so as to straddle the abutting portion of the two terminal portions. -Shaped conductive material is placed, positive and negative polarity electrodes are brought into contact with the upper side of the placed conductive material at the respective terminal portions, pressure is applied, and a predetermined voltage is applied between these electrodes to apply a voltage to both terminals. The FPCs are connected by joining the conductive material of the portion and the conductor wiring by resistance welding (for example, series welding). Further, according to the present invention, the end faces of the terminal portions of the respective FPCs to be connected are abutted so that the conductor wiring is continuous, and each of the FPCs is formed on both the terminal portions so as to straddle the abutting portion of the two terminal portions. A thin plate or thin conductive material is placed on the conductor wiring of the above via a solder, a soldering iron is brought into contact with the upper side of the placed conductive material, and the soldered iron is heated and soldered. Is melted, and the conductive material and the conductor wiring at both ends are joined by soldering to connect the FPCs. Further, according to the present invention, the end faces of the terminal portions of the respective FPCs to be connected are abutted so that the conductor wiring is continuous, and the respective end portions formed on both the terminal portions so as to straddle the abutting portions of the two terminal portions. Place a thin plate or foil conductive material on the conductor wiring of
A horn is brought into contact with one of the upper side of the conductive material placed on each terminal portion and the lower side of the insulating film, and an anvil is brought into contact with the other, and ultrasonic waves of a predetermined frequency are output between these horns and anvils. The FPCs are connected by joining the conductive material and the conductor wiring at both ends by ultrasonic welding. This eliminates the need for components such as dedicated connection connectors, which have been required for the conventional electrical connection between FPCs, so that the cost for connection can be significantly reduced. Further, since the respective conductor wirings of the FPC are joined by, for example, resistance welding, soldering or ultrasonic welding, it is possible to obtain extremely high connection reliability as compared with the connection between FPCs using a dedicated connector or the like. It has the effect of becoming.

[Brief description of the drawings]

FIG. 1 is a top perspective view of a terminal unit for explaining a method of connecting flexible printed circuit boards according to an embodiment of the present invention.

FIG. 2 is a diagram showing an upper surface and a cross section of the terminal unit.

FIG. 3 is a diagram showing an upper surface and a cross section of the terminal unit.

FIG. 4 is a sectional view of a terminal portion for explaining resistance welding.

FIG. 5 is a flowchart showing a connection process between the flexible printed circuit boards.

FIG. 6 is a cross-sectional view of a terminal for explaining a method of connecting flexible printed circuit boards according to another embodiment of the present invention.

FIG. 7: FP used for dashboards of automobiles and the like
It is an upper perspective view which shows C and a wire harness.

FIG. 8 is a diagram for explaining a joint structure of the FPC harness.

[Explanation of symbols]

10, 20,... FPC, 11, 21,.
... end faces, 15, 25 ... insulating films, 16, 26 ... wirings, 17, 27 ... coverlays.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01R 43/02 H01R 43/02 A H05K 1/14 H05K 1/14 H // B23K 101: 38 B23K 101: 38 101: 42 101: 42 F term (reference) 4E067 AA07 BF00 DA13 DA17 EA04 EB00 5E051 KA02 KB04 LA02 LA04 LB05 5E344 AA04 AA12 AA15 AA23 AA28 BB05 CC07 CD13 DD02 DD10 DD13 EE16 EE21

Claims (4)

[Claims] 1. A method for connecting flexible printed circuit boards, each having a conductive wiring formed on an insulating film, comprising: a conductive wiring at a terminal portion of one of the flexible printed boards; End surfaces of the respective terminal portions are abutted so that the conductor wires of the terminal portions are continuous with each other, and a thin plate or a foil-shaped conductive material is provided on the two conductor wires so as to straddle the abutted portions of the both terminal portions. The positive and negative polarity electrodes were brought into contact with the upper side of the above-described conductive material of each terminal portion, and pressure was applied in the film thickness direction of the flexible printed circuit board, and these were brought into contact with each other. A method of connecting flexible printed circuit boards, wherein a predetermined voltage is applied between electrodes to join the conductive material and the conductor wiring of the both end portions by resistance welding. 2. A method of connecting flexible printed circuit boards each having a conductive wiring formed on an insulating film, wherein the conductive wiring at a terminal portion of one flexible printed circuit board and the other flexible printed circuit board are connected. End surfaces of the respective terminal portions are abutted so that the conductor wires of the terminal portions are continuous, and a thin plate or a foil is formed on both the conductor wires via solder so as to straddle the abutted portions of the two terminal portions. The soldering iron is brought into contact with the upper side of the placed conductive material, the heated soldering iron is heated to melt the solder, and the conductive material at the both ends is placed. And connecting the conductive wiring to the flexible printed circuit boards by soldering. 3. A method for connecting flexible printed circuit boards each having a conductive wiring formed on an insulating film, wherein the conductive wiring at a terminal portion of one flexible printed circuit board and the other flexible printed circuit board are provided. End surfaces of the respective terminal portions are abutted so that the conductor wires of the terminal portions are continuous with each other, and a thin plate or a foil-shaped conductive material is provided on the two conductor wires so as to straddle the abutted portions of the both terminal portions. The horn is brought into contact with one of the upper side of the conductive material and the lower side of the insulating film, and the anvil is brought into contact with the other, and the horn and the anvil are brought into contact with each other. A method for connecting flexible printed circuit boards, comprising: outputting ultrasonic waves of a predetermined frequency to the conductive members and joining the conductive material and the conductor wiring of the both end portions by ultrasonic welding. 4. The conductive material has a thickness of 18 μm to 70 μm.
The method for connecting flexible printed circuit boards according to any one of claims 1 to 3, wherein the copper foil is a copper foil.