JPS623895Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial field of application] This invention is a method in which a plurality of conductors arranged on a flexible film base (hereinafter referred to as flexible film conductors) are connected to a plurality of connection conductors of other wiring boards. This invention relates to improvements in wiring devices connected to the .

[Conventional technology]

Conventionally, in such a wiring device, as shown in FIG. 1, one end of a flexible film conductor 3 printed on a flexible film base 1 is connected to one side of a substrate of another wiring section, such as a hard printed circuit board 5. The arrayed terminals 7 were soldered and connected to each other.

That is, the ends 4 and terminals 7 of the conductor 3 are pre-soldered, respectively, and the film base 1 is stacked on the printed circuit board 5 so that the conductor ends 4 and the terminals 7 that correspond to each other are aligned. The conductor 3 and the terminal 7 are connected by applying heat to the overlapped portion. However, in such a connection means, the terminals 7 must be arranged on one side of the wiring board 5, and conductive paths must be formed from other circuit parts on the wiring board 5 to the terminals 7, respectively. First, if the wiring part is printed wiring, the pattern becomes complicated, and the wiring becomes complicated in other cases as well.

In order to avoid such arrangement of the terminals, as shown in FIG. The flexible film bases 11 are stacked on top of the wiring portions with their conductive portions facing outward, and the corresponding terminals 17 and conductor ends 14 are connected as shown in FIG. It is known that the substrate 15 and the film base 11 are connected by a conductive pin 19 passing through the film base 11 and solder connecting the pin 19 and the terminal 17 or the conductor end 14.

In addition, as a connection method that does not use pins, for example, preliminary soldering is applied to the connection part conductor on the flexible film base and the connection part conductor on the rigid printed circuit board, or either one of the parts to be connected. A through hole is provided that passes through the flexible film base of the part and the conductor of the connection part, and the solder surfaces on both the conductors of the connection part are overlapped so that they are in contact with each other, or the solder surface and the conductor are in contact with each other, and then heated with a soldering iron or the like through the through hole. Method of connecting by melting solder
-42742), or, for example, when connecting a connecting conductor on a printed circuit board provided on a flexible film to a connecting conductor on a rigid printed circuit board, the connecting conductor on the flexible film to be connected is A means of providing a through hole penetrating the flexible film and the conductor, overlapping the connecting conductors on both circuit boards, and flowing an adhesive medium such as solder through the through hole for connection (see Japanese Patent Application Laid-Open No. 13860/1986). ) etc. are known.

[Problem that the invention attempts to solve]

However, with the connection means using pins, it is necessary to attach a pin to each connection part between the conductive end 14 and the terminal 17, and solder the top and bottom of the pin, which makes the connection work very troublesome and does not make it suitable for mass production. was not suitable.

In addition, among the connection methods that do not use pins, the connection method described at the beginning requires preliminary soldering to both or one of the connection conductors of both printed circuit boards, and then stacking them facing each other. When bonding, excess melted solder comes out through the through holes, so less solder is pushed out laterally between the connecting conductors than when there are no through holes, and there is less risk of bridging with adjacent circuits. However, if the amount of solder is not adjusted appropriately, it cannot be said that there is a possibility that it will be pushed out laterally and cause bridging, and in this case, it is not visible from the surface, so you will not notice that bridging is occurring. It was hot.

Furthermore, among the connection methods that do not use pins, even with the connection method described later, it is necessary to overlap the connection conductors of both printed circuit boards facing each other, and an insulating material such as a film is interposed in the overlapped portion. In this case, the connection between the two is made by connecting the conductor part located directly below the through hole on the circuit board side without the through hole, and the through hole side wall surface provided in the thin connecting conductor on the circuit board side with the through hole. Since the bonding is done only through an adhesive medium such as solder, the bonding area of the side wall of the through hole is particularly small, making it impossible to obtain sufficient bonding strength.

The present invention solves the above-mentioned disadvantages of the conventional flexible film conductor connection, and provides a flexible film conductor that has high connection strength, allows for random arrangement of the connection conductors on the wiring board, and is easy to connect. It provides a means of connection.

[Means for solving problems]

The present invention connects multiple conductors provided on a flexible film to corresponding conductors on another wiring board, and the multiple conductors on the flexible film are covered with an overlay film except for the solder joints of the connecting conductors. At the same time, a through hole with a smaller diameter than the connecting conductor is drilled through the connecting conductor and the flexible film below it,
The flexible film and the wiring board are overlapped so that the connecting part conductor of the flexible film and the connecting part conductor on the wiring part board to be connected to it overlap with each other through the flexible film, and the connecting part conductor of both is inserted through the through hole. The solder is welded to the connection conductor on the flexible film and spreads laterally in the part not covered by the overlay film, and on the connection conductor of the wiring board, it spreads from just below the through hole to the side. It is characterized in that it has an E-shaped cross section that expands toward the side, and is shaped to hold a flexible film.

[Effect]

The connection portion conductor on the flexible film and the connection portion conductor on the wiring portion substrate connected thereto are overlapped with the flexible film interposed therebetween. The solder that joins both connection conductors is first welded to the peripheral wall of the through hole provided in the connection conductor on the flexible film, and then flows and spreads laterally on the connection conductor in the part not covered by the overlay film. , combine over a large area. Furthermore, since the solder does not spread beyond the overlay film, there is no possibility of short circuits with other connection conductors on the flexible film.

Furthermore, the solder also flows and spreads laterally from just below the through hole on the connection part conductor on the wiring part board, and is bonded over a wide area. Furthermore, even if the solder were to protrude from the top of the connection conductor, the flexible film is interposed between the conductor on the flexible film and the conductor on the wiring board, so there is no chance of a short circuit between the two conductors. do not have.

The solder has an E-shaped cross section and solidifies while sandwiching the flexible film, thereby making it possible to firmly connect both conductors electrically and mechanically.

〔Example〕

FIGS. 4 and 5 show an embodiment of the present invention. FIG. 4 shows a connecting portion between a hard printed circuit board 25, which is a wiring board, and a printed circuit board 30 having a flexible film conductor. FIG. 5 is a perspective view showing the configuration, and FIG. 5 is a cross-sectional view of the connecting portion.

On the hard printed circuit board 25, a plurality of connection conductors, that is, terminals or lands 27a, 27b, 2, are randomly arranged at predetermined positions according to the circuit design.
7c... is formed.

On the other hand, a printed circuit board 30 having a flexible film conductor connected to a circuit on the hard printed circuit board 25 has conductors 23a, 23b, 23c, . . . printed on a flexible film base 21, and A plurality of connection portion conductors 27a, 27b, 27 arranged above
Connecting portion conductors 24a, 24 are located at positions corresponding to c.
b, 24c... are formed. As shown in FIG. 5, the entire surface of the flexible film base 21 is covered with an overlay film 22 to protect the conductors, except for the solder joints of the connecting conductors. Film has been omitted. Through-holes 28a, 28b, 28c, .

Connection conductor 27 on rigid printed circuit board 25
, and the connecting portion conductor 24 on the printed circuit board 30 having a flexible film conductor.
Connection conductor 27 on rigid printed circuit board 25
a, 27b, 27c... and connection portion conductors 24a, 24b, 24c on the flexible film base 21
The conductors 23a of the flexible film base 21 are placed on the rigid printed circuit board 25 so that the non-printed surfaces of the conductors 23a, that is, the film side, are aligned with each other through the through holes 28a, 28b, 28c. . Then, solder connection is performed through through holes 28a, 28b, 28c, . . . provided in the connection portion conductor. The solder also flows and spreads laterally on the surfaces of the connection portion conductors 27a, 27b, 27c, . . . on the printed circuit board 25, and the solder and the connection portion conductors are bonded over a wide area. The solder is also applied to the connection conductor 24 on the printed circuit board 30 having the flexible film conductor.
a, 24b, 24c..., the through hole 28
Not only are they bonded on the peripheral wall surfaces of a, 28b, 28c..., but they also flow laterally on the surface of the connection conductor and spread over the entire solder joint not covered by the overlay film 22, where they are also connected to the solder over a wide area. The conductor is connected to the other conductor. Then, the solder solidifies into an E-shaped cross section to sandwich the flexible film, as shown by reference numeral 29 in FIG. 5, and the bonding is completed.

Although one embodiment of this invention has been described above, the wiring board to which the flexible film conductor is connected is not limited to a rigid printed circuit board, but can also be used on any other board that has a solderable terminal portion, that is, a land. Any wiring board can be used, and flexible film conductors can be connected together.
Also, the through holes may be provided at the terminals of the wiring board, and the connection may be made not only at the ends but also in the middle of the conductor.

[Effect of idea]

As explained above, according to the present invention, a flexible film having a plurality of conductors is stacked on a wiring board, and the connecting part conductor and the wiring board are connected to each other through the through holes of the connecting part conductor on the flexible film. The two can be reliably and firmly connected by simply soldering the connecting conductor to the connecting conductor. Furthermore, since the connecting conductor on the wiring board can be arranged randomly, the wiring on the wiring board can be easily connected. When the wiring is printed wiring, the wiring pattern becomes simple and the design becomes easy, and the required area is also reduced.

In addition, in the present invention, a flexible film base is interposed between the conductor on the flexible film and the conductor on the wiring board, so that the conductor on the flexible film and the conductor on the wiring board can directly oppose each other. Therefore, even if the solder that flows and spreads on the side of the connection conductor on the wiring board protrudes from the connection conductor,
There is no possibility that the protruding solder will short-circuit the conductors on the flexible film and the conductors on the wiring board.

In addition, in the present invention, the solder flows on the connecting conductor on the flexible film, centering on the through hole, and spreading to the sides of the conductor and spreading to the entire area not covered by the overlay film. The spreading range is defined, and there is no fear that solder will flow between the flexible film and other connection conductors and cause a short circuit. In particular, the connection part conductor on a flexible film provided with a through hole is thin because it needs to be flexible, and therefore the area of the side wall of the through hole is also extremely small. When the connecting part conductor is soldered to the connecting part conductor on the other wiring part board with the flexible film base interposed, the soldering is done only at the small area of the through-hole side wall, and the bonding strength is extremely low. However, according to the present invention, the solder also flows sideways on the conductor surface of the through-hole part, and bonds with sufficient strength over a wide area, and the solder as a whole holds the flexible film. Since the flexible film is solidified in an E-shape, it is possible to firmly connect the flexible film to the wiring board, and it is possible to realize a highly reliable connection both electrically and mechanically.

In addition, even if the wiring board is made of a material with high thermal conductivity such as ceramic, and heat escapes in areas other than directly under the through holes of the conductor on the wiring board, it is possible to and the connecting conductor on the flexible film can be bonded with sufficient strength.

Furthermore, since the connecting conductors on the flexible film substrate face outward, electrical connections with other parts can be easily made, and the present invention has many excellent effects.

[Brief explanation of the drawing]

1 to 3 are perspective views or sectional views of the conventional device, FIG. 4 is a perspective view of the embodiment of the present invention, and FIG.
The figure is a sectional view of an embodiment of the present invention. 21: Flexible film, 22: Overlay film, 23: Conductor, 24, 27: Connection conductor, terminal, or land, 28: Through hole, 29: Solder, 25: Printed circuit board as wiring board, 3
0: Printed circuit board with flexible film conductor.

Claims (1)

[Scope of utility model registration request] In a device that connects multiple conductors provided on a flexible film to corresponding conductors on another wiring board, the multiple conductors on the flexible film cover the overlay film except for the solder joints of the connecting conductors, and A through hole with a smaller diameter than the connecting conductor is formed through the connecting conductor and the flexible film below it, so that the connecting conductor of the flexible film and the connecting conductor on the wiring board to be connected to it are connected to each other. The flexible film and the wiring part board are overlapped with the flexible film in between, and the connection part conductors of both are soldered together through the through holes, and the solder is welded to the connection part conductor on the flexible film and overlaid. It spreads laterally in the part not covered with the film, and on the connection part conductor of the wiring part board, it spreads laterally from just below the through hole, forming an E-shaped cross section, so that it is shaped to hold the flexible film. A wiring device having a flexible film conductor, characterized in that: