JPH0378909A - Structure for drain wire in tape cable with shield and connecting method of sheild layer and drain wire - Google Patents

Abstract

PURPOSE:To firmly hold the linear stripes of a drain wire in a bonded contact state so as to keep stable conduction for a long period by forming notched grooves for splitting in the longitudinal direction on the upper and lower surfaces of the drain wire. CONSTITUTION:Notched grooves 12-1 for splitting are formed in the longitudinal direction on the upper and lower surfaces of a drain wire 12. The drain wire 12 is split along notched grooves 12-1 to be divided into two linear stripes 12-2. One of the linear stripes 12-2 is folded lengthwise to be superposed on a shield layer 14, and then, the shield layer 14 is electrically conducted to the drain wire 12. In the case where the shield layer 14 is made of a metallic foil tape, one of the linear stripes 12-2 of the drain wire 12 is folded on the metallic foil tape, and further, an insulative tape 15 coated with adhesive is wound around the metallic foil tape to be formed integrally with application of pressure on the upper and lower surfaces. Therefore, the shield layer 14 is brought into a firm contact with the drain wire 12, thereby avoiding any conductive deficiency to enhance reliability.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to the structure of a drain wire in a shielded tape electric wire and a method for connecting the shield layer and the drain wire in a shielded tape electric wire in which rectangular conductors are exposed at both ends. It is related to.

(Prior Art) Tape wires are widely used in signal transmission circuits between printed circuit boards of electronic devices, and shielded tape wires are used when electrical shielding is required. A schematic diagram of the structure of this type of shielded tape electric wire is shown in FIG. Figure 3 (a)
is a plan view, and FIG. 3(b) is an enlarged sectional view. In these figures, 1 is a signal line made of a rectangular conductor, and 2 is a drain wire also made of a rectangular conductor. Required number (
The signal wires 1 (four wires in the figure) and the drain wires 2 are lined up in parallel, sandwiched between plastic insulating tapes 3 made of polytetrafluoroethylene, polyester, flame-retardant polyethylene, etc. in a sandwich-like manner, and are tightly integrated. At this time, an appropriate opening 4 is formed in the insulating tape 3 on one side to expose the drain wire 2, a shield layer 5 is encapsulated so as to cover the entire area, and the overlapping part 6 is pressed. , the drain wire 2 and the shield layer 5 are brought into contact with each other.

For the shield layer 5, a copper-plastic laminate tape is usually used, in which a plastic tape is laminated on one side of the copper tape and an adhesive is intermittently applied on the other side, and the tape is placed vertically with the copper tape side inside. It is wrapped and pressed from both sides to form a single piece.

(Problem to be Solved by the Invention) In the shielded tape electric wire of the conventional structure as described above, the signal wire 1 and the drain wire 2 are arranged evenly in a horizontal line in order to facilitate the design of the connector for the -batch connection. An opening 4 is provided in the insulating tape 3 to expose the drain wire 2. Therefore, a step is created in this portion by the thickness of the insulating tape 3. The shield layer 5 is wrapped on the insulating tape 3, and the shield layer 5 and the drain wire 2 are brought into contact with each other by applying pressure from the outside so that the shield layer 5 and the drain wire 2 are electrically connected to each other at the opening 4 having the step. The shield layer 5 and the drain wire 2 are bonded to each other by the adhesive applied intermittently to the shield layer 5 as described above, but the shield layer 5 and the drain wire 2 are simply physically bonded in the areas where the adhesive is not applied. It is only in contact with. Therefore, in the case of bending, the contact state becomes unstable, which may increase contact resistance, cause poor conduction, and reduce shielding performance. Further, since a large pressing force is required to bring the shield layer 5 and the drain wire 2 into contact at the stepped portion, large pressurizing equipment is required.

(Means for Solving the Problems) The present invention has been made to solve the above problems, and consists of connecting a plurality of signal lines and drain wires, both made of rectangular conductors, in parallel between plastic insulating tapes. The drain wire in the shielded tape electric wire, which is arranged in parallel and integrated and provided with a shield layer covering the whole, has a drain wire structure in which cut grooves for tearing are provided in the longitudinal direction on both sides.

In addition, in the shielded tape electric wire as described above, in which the shielded tape electric wire is exposed at both ends and the signal line and the drain wire are exposed, the drain wire is cut into a groove in the exposed portion of the drain wire at least at one end. This is a connection method in which a filament is torn along the line to form two divided filaments, one of the filaments is folded back in the length direction and overlapped with the shield layer, and electrical continuity is established between the shield layer and the drain wire.

If the shield layer is made of metal foil tape, fold one of the torn strands of the drain wire onto the metal foil tape, wrap it with an insulating tape coated with adhesive, and wrap it from both sides. Press and form into one piece. In addition, when the shield layer is made of a laminated tape of copper tape and plastic tape as in the conventional example, one torn filament of the drain wire is folded back onto the insulating tape on the drain wire, and the laminated tape is placed on top of this. Encapsulate the copper tape so that the surface is on the inside, and pressurize from both sides to mold it into one piece.

(Function) As a drain wire having the above structure, the shield layer and the drain wire are brought into contact with each other and are firmly bonded together by being pressurized from the outer surface of the shield layer or insulating tape by the method of connecting the shield layer and the drain wire as described above. Since the divided strips of the drain wire are sandwiched between these tapes, the strips of the drain wire are also firmly bonded and held, and even when bent, the shield layer and the drain wire remain in close contact. Because of this, stable conduction can be obtained over a long period of time.

(Example) FIG. 1 is an enlarged sectional view of a drain wire in a shielded tape electric wire according to the present invention. Drain wire 12
has a structure in which cut grooves 12-1 for tearing are provided in the longitudinal direction of both sides of the rectangular conductor, and by appropriately selecting the thickness t at the bottom of the cut grooves 12-1 in the figure, this cut can be made. It can be easily torn at the groove 12-1. By the way,
For example, a = 200 ttm, b = 1000m,
Although c=200-1t=100-, it could be easily torn. Note that since the drain wire is thin, perforations may be provided instead of the cut grooves 12-1.

FIG. 2 is a perspective view of an embodiment of a shielded tape electric wire constructed by the method of connecting a shield layer and a drain wire according to the present invention. In the figure, 11 is a signal line made of a rectangular conductor, and 12 is a drain wire formed as shown in FIG. They are placed in parallel and insulated from both sides by being sandwiched in a sandwich-like manner by plastic insulating tape 13 made of polytetrafluoroethylene, polyester, flame-retardant polyethylene, etc., and are bonded to the inner surface so as to cover the whole. A shield layer 14 made of a copper tape coated with a coating agent is provided, and the signal line 11 and the drain wire 12 are exposed at both ends in the length direction. The cut groove 12 shown in FIG.
-1 to tear it into two parts, and one of the striatum 12
-2 is folded back and overlapped on the shield layer 14, and from above that, an insulating tape 15 whose inner surface is coated with an adhesive
is brought into close contact with the shield layer 14 to strengthen the contact between the shield layer 14 and the drain wire 12.

Note that when wrapping a laminate tape made of a copper tape and a plastic tape as a shield layer with the copper side facing inside as in the conventional example, the filament 12-2 of the drain wire 12 is wrapped with the insulating tape 13, although not shown. It is folded upward, and the above-mentioned laminate tape is wrapped over this with the copper side facing inside, and then pressure is applied from both sides to form it.

(Effect of the invention) In a shielded tape electric wire, if the structure of the drain wire is formed with the cut groove according to the present invention and the method of connecting the shield layer and the drain wire according to the present invention is used, the contact state between the shield layer and the drain wire can be improved. is strong, preventing conduction defects and improving reliability. Moreover, a smaller pressing force than before is sufficient, and the process of providing openings in the plastic insulating tape can be omitted.

[Brief explanation of drawings]

Fig. 1 is an enlarged sectional view of a drain wire according to the present invention in a shielded tape electric wire, Fig. 2 is a perspective view of a shielded tape electric wire constructed by the method of connecting a shield layer and a drain wire according to the present invention, and Fig. 3 is a conventional (A) is a plan view and (B) is an enlarged cross-sectional view of the example shielded tape electric wire. 11: Signal line, 12: Drain wire, 12-1: Cut groove for tearing, 12-2: Stray body of drain wire to be torn, 13 Niblast insulation tape, 14: Shield layer,
15: Insulating tape. Figure 1

Claims (1)

[Claims] 1. A shield in which a plurality of signal lines and drain wires, both made of rectangular conductors, are sandwiched and integrated in parallel between plastic insulating tapes, and a shield layer that covers the whole is provided. A drain wire for a shielded tape electric wire, characterized in that the drain wire is provided with tear grooves in the longitudinal direction on both sides. 2. Cut the drain wire at the exposed portion of the drain wire at at least one end of the shielded tape electric wire having the drain wire according to claim 1, in which the signal line and the drain wire are exposed at both ends. The method involves tearing along the drainage groove to form two divided filaments, and folding one of the filaments in the length direction to overlap the shield layer to ensure electrical continuity between the shield layer and the drain wire. A method of connecting the shield layer and drain wire in a characteristic shielded tape electric wire.