JPH06243730A - Shielded flat cable - Google Patents

Abstract

PURPOSE:To obtain a flat cable at a low cost, which is shielded excellently, without providing a separate drain line for grounding the shielding material. CONSTITUTION:The surface of a flat cable 10 is coated with the shielding material 20, and this shielding material 20 is coated for insulation with an insulating layer 30. The shielding material 20 has a connecting projection as a drain line to be laid on a conductor exposure part 14 of the flat cable 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shielded flat cable, and more particularly to a shielded flat cable which does not require a separate drain wire for grounding a shield material and which has a low manufacturing cost and excellent shielding performance. The flat cable here is used as a generic name for flat multicore electric wires, and is a concept including ribbon electric wires, tape electric wires, and the like.

[0002]

2. Description of the Related Art With the recent miniaturization of electronic devices and the like, electric wires and the like used in those devices have been improved, and electric wires called flat cables in which a plurality of conducting wires are sandwiched by insulating layers are frequently used. . Also, electronic devices may malfunction due to external electromagnetic waves.
In order to prevent such electromagnetic interference, a shielded flat cable in which the above flat cable is shielded has been developed.

Conventionally used shielded flat cables are shown in FIGS. 10 and 11 (see Japanese Patent Laid-Open No. 4-27617). The shielded flat cable 50 has adhesive layers 51a, 5
In the flat cable in which the conducting wire 53 is sandwiched by the insulating tapes 51 and 52 having 2a, a part of the position corresponding to one conducting wire 53 is peeled off from one insulating tape 51 to expose the exposed portion 51b of the conducting wire 53. The shield tape 54 formed and wound around the insulating tapes 51 and 52 is electrically connected to the conductor wire 53 through the exposed portion 51b. By grounding the conductor wire 53 as a drain wire to the ground, , The shield effect can be obtained.

However, a part of the thin insulating layer 51 is connected to the conductive wire 53.
It is not easy to expose the conductive wire 53 by peeling it off so as not to damage it, and there is a disadvantage that the working efficiency is very poor.

Therefore, a shielded flat cable 60 as shown in FIG. 12 has been developed (Japanese Patent Laid-Open No. 4-332).
No. 11). This shielded flat cable 6
0 is a plurality of conducting wires 62a to 62 on one insulating layer 61.
d is arranged in parallel, and the other insulating layer 6 is formed so that the upper surfaces of the other conductors 62d are exposed on the upper surfaces of the conductors 62a to 62c.
3 is provided, and the shield material 64 is further covered from above to electrically connect the conductor wire 62d and the shield material 64, and the conductor wire 62d is used as a drain wire.

[0006]

The shielded flat cable 60, which is different from the shielded flat cable 50, is manufactured in that it is not necessary to peel off a part of the insulating layer 51 to form the exposed portion 51b. Can be said to be easy.

However, the shielded flat cables 50 and 60 are both shield tape 54 and shield material 64.
Since the drain lines 53 and 62d for grounding the drain to the ground are separately provided, the material cost becomes high and the drain lines 53 and 62d and the shield tape 54 are inevitably inevitable.
An electrical connection portion may be formed between the shield material 64 and the shield performance may be deteriorated due to an increase in resistance of the electrical connection portion or a non-connection. Further, in order to increase the reliability of the shield performance, it is necessary to securely connect the two by soldering, welding, etc., which causes the disadvantages such as a decrease in production efficiency due to an increase in man-hours and an increase in manufacturing cost. .

SUMMARY OF THE INVENTION An object of the present invention is to provide a shielded flat cable which does not require a separate drain wire for grounding the shield material to the ground and which has a low manufacturing cost and excellent shielding performance.

[0009]

In order to solve the above problems, the present invention relates to a shielded flat cable in which a flat cable is covered with a shield member except for the exposed conductor portions located at both ends of the flat cable. A part of the member is taken out as a drain wire and held in the exposed portion of the conductive wire.

[0010]

[Function] In the shielded flat cable configured as described above, since a part of the shield material is used as the drain wire, it is not necessary to separately provide the drain wire, and naturally, the drain wire and the shield material are electrically connected. There are no connections.

[0011]

EXAMPLES Examples will be described below with reference to the drawings. As shown in FIGS. 1 and 2, in this shielded flat cable, the surface of the flat cable 10 is covered with a shield material 20.
Is covered with an insulating layer 30.

The flat cable 10 is made of polyethylene terephthalate (PE) having an adhesive layer and a thickness of 25 μm.
T) A tin-plated annealed copper foil 12 having a conductor width of 0.3 to 1.0 mm is arranged in parallel on the film 11 at a constant pitch (0.5 to 2 mm).
Thickness 0.3 overcoated with T film 13
It is about 5 to 0.5 mm, but at both ends,
As a terminal connecting portion, a lead wire exposed portion 14 in which an end portion of the tin-plated annealed copper foil 12 is exposed is formed in a lacking portion of one PET film 13.

Further, the conductor wire exposed portion 14 is provided with an area A for disposing the connecting projection 21 of the shield member 20 on one side in the width direction, and the outer surface of both ends of the PET film 11 is secured. A reinforcing plate 15 for reinforcing the exposed conductor portion 14 is fixed to the side.

As shown in FIG. 5, the shield member 20 is formed of a copper foil B having a thickness of 0.35 to 0.5 mm and having an adhesive layer b made of a hot melt thermoplastic adhesive. It is attached to the outer surfaces of the PET films 11 and 13 so that the inside of b is covered and the substantially entire surface of the flat cable 10 excluding the conductor exposed portion 14 is covered.

The shield material 20 is integrally formed with connecting projecting pieces 21 functioning as drain wires at both ends thereof, and the connecting projecting pieces 21 are lined up with the tin-plated annealed copper foil 12 to expose the conductive wire exposed portion 14. It is attached to the area A. In addition,
Due to the presence of the reinforcing plate 15, the shield material 20 is
The PET film 11 side is shorter than the PET film 13 side.

The insulating layer 30 has a thickness 2 having an adhesive layer.
It is made of a PET film having a thickness of 5 μm, and covers the entire surface of the shield material 20 excluding the connecting projections 21 together with a part of the reinforcing plate 15. The thickness of the PET films 11 and 13 and the shield layer 30 is 25 μm.
It is not limited to m, and may be set freely within the range of 10 to 300 μm.

A method of manufacturing the shielded flat cable will be described below. First, as shown in FIG.
The flat cable 10 and the shield material 20 described above are prepared. As shown in FIG. 3, the shield material 20 is formed by cutting out the hatched portion from the copper foil B having a constant shape having an adhesive layer, but as shown in FIG.
In order to reinforce the base portion of the, the corner portion 21a is formed in a curved shape. The length L may be set in advance in consideration of the bending tolerance of the terminal, or the excess of the tip may be cut and aligned after coating.

Next, as shown in FIG. 7, the shield material 20 is superposed on the PET film 13 side of the flat cable 10 and the connecting projection 21 thereof is guided to the conductor exposed portion 14 to form the tin-plated annealed copper foil 12. Lay them in parallel.

After that, as shown in FIG. 8, the remaining portion of the shield material 20 is folded back to form the PE of the flat cable 10.
Overlay on the T film 11 side,
By heating and pressing from both sides of 13, the shield material 20 is adhesively coated on the flat cable 10.

Finally, a PET film is adhesively coated as the insulating layer 30 to complete a shielded flat cable as shown in FIG.

In this embodiment, the shield material 20 and the insulating layer 30 are individually coated, but if a shield material with an insulating layer formed by previously coating a copper foil with a PET film is used, the number of steps is reduced. Manufacturing efficiency is improved. However, in this case, the insulating layer of the connecting projection 21 needs to be peeled off in advance.

Further, in this embodiment, the connecting projection 21 is laid on one side in the width direction of the flat cable, but it is not particularly limited to this position and may be arbitrarily determined.

The tin-plated annealed copper foil 12 which is the conductor of the flat cable 10 may be a foil such as copper or annealed copper, which is a general conductor material, or a rectangular conductor, and the shield member 20 also uses the same conductive material as the conductor. .

Since the end of the shielded flat cable is used by inserting it into the connector, the tin-plated annealed copper foil 12 of the exposed wire portion 14 and the connecting projection 21 of the shield member 20 are used.
Are preferably aligned at the same height.

Further, since the tin-plated annealed copper foils 12 are laid in parallel at the same pitch, it is basic that the connecting projections 21 are also laid at the same pitch. It may be laid at different pitches depending on the shape and the connection method.

[0026]

As described above, since the shielded flat cable of the present invention adopts the structure in which a part of the shield material is used as the drain wire, it is not necessary to separately provide the drain wire as in the conventional case, and the material cost can be reduced. The manufacturing cost is low, the manufacturing is easy, and the manufacturing cost can be reduced.

Further, as a matter of course, since there is no electric connection between the drain wire and the shield material, the shield performance is not deteriorated due to the defect of the electric connection, and the reliability of the product is improved.

Further, since a part of the shield member taken out as the drain wire is held in the exposed portion of the conductor wire in a pre-exposed state like the conductor wire, it is not necessary to process the end of the flat cable at the time of connection, so that connection work can be performed. It will be easier.

Particularly, in the case where a part of the shield member taken out as the drain wire is formed to have the same width and the same thickness as the conductor wire, there is also an advantage that ordinary connectors and connecting members can be used as they are.

[Brief description of drawings]

FIG. 1 is a partial perspective view showing an embodiment according to the present invention.

FIG. 2 is a cross-sectional view of a connecting projection piece portion of the above.

FIG. 3 is a plan view showing a manufacturing process of the shield material.

FIG. 4 is a detailed view showing a part of the shield material.

FIG. 5 is a cross-sectional view showing a forming material of a shield material.

FIG. 6 is a diagram showing a manufacturing process same as above.

FIG. 7 is a diagram showing a manufacturing process same as above.

FIG. 8 is a diagram showing a manufacturing process same as above.

FIG. 9 is a diagram showing a manufacturing process same as above.

FIG. 10 is a plan view showing a conventional example.

11 is a cross-sectional view taken along line XX of FIG.

FIG. 12 is a perspective view showing another conventional example.

[Explanation of symbols]

 10 Flat Cable 11, 13 PET Film 12 Tinned Annealed Copper Foil 14 Conductive Wire Exposed Area 15 Reinforcement Plate 20 Shielding Material 21 Connecting Projection Piece 30 Insulating Layer B Copper Foil b Adhesive Layer

Claims (2)

[Claims] 1. A shielded flat cable in which a flat cable is covered with a shield member except for exposed conductor portions located at both ends thereof, and a part of the shield member is taken out to the exposed conductor portion as a drain wire. A flat cable with a shield that has been retained. 2. The shield member is made of the same material as the conductor of the flat cable, and a part of the shield member taken out as a drain wire is formed to have the same width and the same thickness as the conductor of the conductor exposed portion. The shielded flat cable according to claim 1.