JP2017201610A - Shielded flexible flat cable and manufacturing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a shielded flexible flat cable excellent with regard to a production cost.SOLUTION: A shielded flexible flat cable includes: a flat cable main body having a plurality of conductors arranged in parallel and including one or a plurality of ground lines, and an insulator layer disposed around the plurality of conductors; and a shield tape disposed so as to cover the flat cable main body. The shield tape includes a shield layer and an adhesive layer being non-conductive and laminated on the shield layer at a side of the flat cable main body. In the plurality of conductors, the one or plurality of ground lines and the shield layer are electrically connected. The one or a plurality of ground lines of the flat cable main body are exposed to a surface side of the flat cable main body at part of a shield tape coating region and to form one or a plurality of projections on a surface side.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a shielded flexible flat cable and a method for manufacturing the same.

  As electronic devices become smaller and lighter, electrical wiring members between electronic components mounted on electronic devices are required to be small and highly flexible so that wiring can be performed in a limited space. As such an electrical wiring member, for example, a flexible flat cable using a flexible rectangular conductor can be cited. In particular, a shielded flexible flat cable having a shielding function is used for wiring of an electronic device particularly requiring noise countermeasures.

  In the flexible flat cable, a plurality of conductors including a ground wire are arranged in parallel, and an insulating layer is disposed around the plurality of conductors. In the shielded flexible flat cable, a shield layer such as a metal foil is further provided so as to cover the insulating layer, and the ground line and the shield layer are electrically connected.

  As an electrical connection structure between the shielded flexible flat cable ground wire and the shield layer, a structure is proposed in which the ground wire is exposed on the surface side of the insulating layer and the exposed ground wire and shield layer are electrically connected. (See JP 2009-123563 A). Specifically, in this conventional shielded flexible flat cable, the ground wire is cut at a place other than the end portion in the longitudinal direction, the cut ground wire is folded back to the surface side of the insulating layer, and the exposed ground wire is exposed. A shield layer is disposed through a conductive adhesive layer so as to cover the surface. In the above-described conventional shielded flexible flat cable, the ground wire folded back to the surface side of the insulating layer and the shield layer are electrically connected by the conductive adhesive layer.

JP 2009-123563 A

  In the conventional structure, the ground wire and the shield layer are bonded via the conductive adhesive layer. This conductive adhesive contains, for example, a conductive filler, and the ground wire and the shield layer are electrically connected via the conductive filler. Therefore, in order to electrically connect the ground line and the shield line stably, it is necessary to apply a relatively thick conductive adhesive to increase the density of the conductive filler. In the conventional structure, since the conductive adhesive layer also serves to bond the shield layer and the insulating layer, the conductive adhesive is applied to a portion other than the portion where the ground line and the shield layer are connected. Therefore, the conventional structure requires a relatively large amount of conductive adhesive. Furthermore, since this conductive adhesive has a higher cost per unit amount than the non-conductive adhesive, the conventional shielded flexible flat cable is likely to have a high manufacturing cost and there is room for improvement.

  This invention is made | formed based on the above situations, and aims at provision of the flexible flat cable with a shield which is excellent in manufacturing cost, and its manufacturing method.

  A shielded flexible flat cable according to one aspect of the present invention includes a plurality of conductors arranged in parallel and including one or a plurality of ground wires, and an insulating layer disposed around the plurality of conductors. And a shielded flexible flat cable provided to cover the flat cable body, the shield tape being laminated on the flat cable body side of the shield layer and the non-conductive layer Adhesive layer, and one or more ground wires of the plurality of conductors and the shield layer are electrically connected, and one or more ground wires of the flat cable main body, A part of the shield tape covering region is exposed on the surface of the flat cable main body, and one or more protrusions on the surface side It is configured to form.

  A method for manufacturing a shielded flexible flat cable according to another aspect of the present invention includes a plurality of conductors arranged in parallel and including one or a plurality of ground wires, and an insulating layer disposed around the plurality of conductors. And a shielded flexible flat cable comprising a shield tape disposed to cover the flat cable body, wherein the shield tape is laminated to the shield layer. A non-conductive adhesive layer, the step of partially exposing the ground wire of the flat cable body to the surface of the flat cable body, and one or a plurality of ground wire exposed portions of the flat cable body Covering the ground wire exposed part on the surface side of the flat cable body, And a step in which the adhesive layer is disposed the shield tape to be a flat cable body, and a step of thermocompression bonding the flat cable body and the shield tape.

  The shielded flexible flat cable and the manufacturing method thereof of the present invention are excellent in manufacturing cost.

It is a top view of the flexible flat cable with a shield of one embodiment of the present invention. It is sectional drawing in the AA line of the flexible flat cable with a shield of FIG. It is sectional drawing in the BB line of the flexible flat cable with a shield of FIG. It is sectional drawing in the CC line of the flexible flat cable with a shield of FIG.

[Description of Embodiment of the Present Invention]
A shielded flexible flat cable according to one aspect of the present invention includes a plurality of conductors arranged in parallel and including one or a plurality of ground wires, and an insulating layer disposed around the plurality of conductors. And a shielded flexible flat cable provided to cover the flat cable body, the shield tape being laminated on the flat cable body side of the shield layer and the non-conductive layer Adhesive layer, and one or more ground wires of the plurality of conductors and the shield layer are electrically connected, and one or more ground wires of the flat cable main body, A part of the shield tape covering region is exposed on the surface of the flat cable main body, and one or more protrusions on the surface side It is configured to form.

  In the shielded flexible flat cable, the ground wire exposed on the surface of the flat cable body has a convex portion. The protrusions are in close contact with the shield layer by pressing with the shield tape, so that the ground line and the shield layer are electrically and stably connected. Therefore, the shielded flexible flat cable does not require the ground wire and the shield layer to be electrically connected by the adhesive layer, and the adhesive layer can be made nonconductive. Since it is not necessary to consider conductivity, the non-conductive adhesive layer can be made thinner than the conductive adhesive layer. For this reason, the said flexible flat cable with a shield can reduce the application quantity of an adhesive agent. Furthermore, the non-conductive adhesive has a lower cost per unit amount than the conductive adhesive. Therefore, the shielded flexible flat cable can reduce the manufacturing cost as compared with the conventional shielded flexible flat cable.

  The one or more ground wires are cut at a part of the shield tape covering region of the flat cable body, and the cut one side is folded back to the surface side and exposed to the surface of the flat cable body. Good. In this way, the ground line is folded back and exposed to the surface of the flat cable body, so that the pressing of the ground line toward the insulating layer by the shield layer is enhanced in the ground line exposed portion. Therefore, the electrical contact between the convex portion of the ground line and the shield layer can be further improved.

  A concavo-convex sheet having irregularities on the ground line side may be provided between the folded ground line and the insulating layer. By providing a concavo-convex sheet between the folded ground line and the insulating layer in this way, when the ground line is folded, the ground line bends along the concavo-convex surface of the concavo-convex sheet, and the ground line is exposed. The convex portion can be formed relatively easily.

  The uneven sheet may be a mesh sheet or a sheet having an embossed surface. Such a mesh-like sheet or a sheet having an embossed surface is relatively inexpensive, and the manufacturing cost can be further reduced. Further, even when the ground line is displaced when the ground line is folded, a convex portion can be formed in the exposed portion of the ground line.

  A method for manufacturing a shielded flexible flat cable according to another aspect of the present invention includes a plurality of conductors arranged in parallel and including one or a plurality of ground wires, and an insulating layer disposed around the plurality of conductors. And a shielded flexible flat cable comprising a shield tape disposed to cover the flat cable body, wherein the shield tape is laminated to the shield layer. A non-conductive adhesive layer, the step of partially exposing the ground wire of the flat cable body to the surface of the flat cable body, and one or a plurality of ground wire exposed portions of the flat cable body Covering the ground wire exposed part on the surface side of the flat cable body, And a step in which the adhesive layer is disposed the shield tape to be a flat cable body, and a step of thermocompression bonding the flat cable body and the shield tape.

  In the manufacturing method of the shielded flexible flat cable, a convex portion is formed on the ground wire exposed portion, and the flat cable body and the shield tape are thermocompression bonded so as to cover the ground wire exposed portion. As a result of this thermocompression bonding, the adhesive layer melts, and the convex portion formed on the ground wire penetrates the adhesive layer and presses against the shield layer, so that the ground wire and the shield layer are electrically connected. Therefore, it is not necessary to connect the ground line and the shield layer with the adhesive layer, and the adhesive layer can be made nonconductive. For this reason, the manufacturing method of the said shielded flexible flat cable can reduce the cost of the adhesive agent used for an adhesive bond layer compared with the conventional manufacturing method made into an electroconductive adhesive bond layer. Therefore, the manufacturing method of the said flexible flat cable with a shield is excellent in manufacturing cost.

[Details of the embodiment of the present invention]
Hereinafter, a shielded flexible flat cable and a manufacturing method thereof according to an embodiment of the present invention will be described in detail with reference to the drawings.

[Shielded flexible flat cable]
The flexible flat cable with shield shown in FIGS. 1 to 4 includes a flat cable body 1, a shield tape 2 disposed so as to cover the flat cable body 1, and unevenness disposed in the flat cable body 1. With sheet 3

<Flat cable body>
The flat cable body 1 includes a plurality of conductors 10 arranged in parallel and an insulating layer 11 disposed around the plurality of conductors 10. The plurality of conductors 10 include a plurality of ground lines 10G. The flat cable body 1 has a rectangular shape in which the length in the arrangement direction of the plurality of conductors 10 is larger than the length in the thickness direction in a cross-sectional view perpendicular to the length direction.

  The flat cable body 1 has a folded structure of a plurality of ground wires 10G on one surface side. Hereinafter, as shown in FIG. 2, the side where the flat cable body 1 has the folded structure of the ground wire 10G will be described as the upper surface side, and the opposite surface side will be described as the lower surface side.

  The folded structure of the ground line 10G is configured such that the ground line 10G and the insulating layer 11 stacked on the upper surface side of the ground line 10G in a state before folding are folded back on the upper surface side. Therefore, the folded insulating layer 11 is located on the lower surface side of the folded ground line 10G, and the folded ground line 10G is exposed on the surface of the flat cable body 1. A part of the exposed ground line 10 </ b> G is electrically connected to the shield tape 2.

(conductor)
Although it does not specifically limit as the conductor 10, For example, common conductors, such as strands and twisted wires, such as copper, a copper alloy, and tin plating copper, can be used. In addition, acicular crystals (whiskers) may be generated on the surface of the conductor 10 due to receiving compressive stress at a portion connected to an electronic component or the like. May be plated with gold. By performing gold plating in this manner, it is possible to make it difficult for a short circuit due to whiskers between the conductors 10 to occur even when the conductors 10 are arranged at a narrow pitch.

  Although it does not specifically limit as a cross-sectional shape of the conductor 10, From a viewpoint that the average thickness of the flat cable main body 1 can be made thin, it can be made into a rectangular shape, for example. The average thickness and average width of the cross section when the cross section of the conductor 10 is a rectangular shape are determined by the required resistivity of the conductor 10 and the like. As a minimum of average thickness of conductor 10, 10 micrometers is preferred and 20 micrometers is more preferred. On the other hand, the upper limit of the average thickness of the conductor 10 is preferably 100 μm and more preferably 70 μm. Moreover, as a minimum of the average width | variety of the conductor 10, 0.1 mm is preferable and 0.3 mm is more preferable. On the other hand, the upper limit of the average width of the conductor 10 is preferably 3 mm, and more preferably 2 mm.

  The number of conductors 10 is determined according to the number of signals required, and can be, for example, 2 or more and 100 or less. Moreover, as a minimum of the average space | interval (average width of a gap) of the conductor 10 arranged in parallel, 0.1 mm is preferable and 0.2 mm is more preferable. On the other hand, the upper limit of the average distance between the conductors 10 is preferably 0.7 mm, and more preferably 0.5 mm. There exists a possibility that a short circuit may generate | occur | produce between the conductors 10 that the average space | interval of the said conductor 10 is less than the said minimum. On the other hand, if the average interval between the conductors 10 exceeds the upper limit, there is a risk that the requirement for downsizing of the electronic device is violated.

(Ground line)
The ground line 10 </ b> G is arranged in parallel with the other conductors 10. The ground wire 10G is cut halfway, and one side of the cut is folded back to the upper surface side of the flat cable body 1 together with the insulating layer 11 laminated on the upper surface side of the ground wire 10G in a state before folding. For this reason, the flat cable body 1 has a gap at a position before the ground wire 10G and the insulating layer 11 are folded back.

  The folded ground wire 10 </ b> G is exposed on the surface of the flat cable body 1. Further, since the folded ground line 10G is electrically connected to the shield tape 2, it is folded so as to be located in a part of the shield tape covering region of the flat cable body 1.

  Further, the folded ground line 10G is bent along the unevenness of the surface of the uneven sheet 3 described later. Thus, the ground line 10G is configured to form a plurality of convex portions on the surface side.

  The lower limit of the average length in plan view of the portion (ground wire exposed portion) where the ground wire 10G is folded and exposed on the upper surface of the flat cable body 1 is preferably 5 mm, and more preferably 7 mm. On the other hand, the upper limit of the average length of the exposed portion of the ground line is preferably 15 mm, and more preferably 13 mm. If the average length of the exposed portion of the ground line is less than the lower limit, the connection resistance between the ground wire 10G and the shield layer 20 may increase. Since the average length of the gap substantially coincides with the length obtained by linearly extending the exposed portion of the ground line, the volume of the gap increases as the average length of the exposed portion of the ground line increases. For this reason, if the average length of the exposed portion of the ground wire exceeds the upper limit, the strength of the flat cable body 1 may be insufficient due to an increase in the volume of the gap.

  The lower limit of the average height of the protrusions of the ground line 10G is preferably 5 μm and more preferably 10 μm. On the other hand, the upper limit of the average height of the convex portions is preferably 50 μm, and more preferably 30 μm. If the average height of the protrusions is less than the lower limit, the protrusions may not be sufficiently pressed against the shield layer 20 and the contact resistance between the ground wire 10G and the shield layer 20 may increase. On the contrary, if the average height of the convex portion exceeds the upper limit, the convex portion is bent by the pressure from the shield layer 20, and the contact between the ground wire 10G and the shield layer 20 may be insufficient. In addition, the average height of a convex part refers to the average value of the height difference (H shown in FIG. 2) of the height direction of the ground line 10G of an adjacent peak and valley.

  The lower limit of the ratio of the total contact area of the ground line 10G with the shield layer 20 to the area of the exposed portion of the ground line in plan view is preferably 20%, and more preferably 30%. On the other hand, the upper limit of the ratio of the total contact area is preferably 50%, and more preferably 40%. When the ratio of the total contact area is less than the lower limit, the connection resistance between the ground wire 10G and the shield layer 20 may increase. Conversely, when the ratio of the total contact area exceeds the upper limit, the pressure from the shield layer 20 is dispersed, and the contact between the ground wire 10G and the shield layer 20 may become unstable.

  The average interval between adjacent convex portions of the ground line 10G in the case where there are a plurality of the convex portions (the average of the intervals between the top portions of the convex portions) is determined by the convex portion interval of the concavo-convex sheet 3 described later. The lower limit of the average interval is preferably 0.5 mm and more preferably 1 mm. On the other hand, the upper limit of the average distance between the convex portions is preferably 5 mm, and more preferably 4 mm. If the average interval between the protrusions is less than the lower limit, it is difficult to form the protrusions, and the manufacturing cost for forming the protrusions may increase. On the contrary, if the average interval between the convex portions exceeds the upper limit, the number of convex portions decreases, so that the contact resistance between the ground line 10G and the shield layer 20 may increase.

(Insulating layer)
The insulating layer 11 is disposed between the pair of insulating films 11a disposed so as to sandwich the plurality of conductors 10 and the pair of insulating films 11a, and is disposed so as to cover the periphery of the conductors 10. A conductor holding adhesive layer 11b.

  The insulating film 11a is not particularly limited as long as it has insulating properties, and examples thereof include resin films such as polyester, polyimide, and polyphenylene sulfide (PPS). Among them, a polyester resin film that can easily form the opening 12 described later is preferable.

  The lower limit of the average thickness of each of the pair of insulating films 11a is preferably 9 μm, and more preferably 12 μm. On the other hand, the upper limit of the average thickness of the insulating film 11a is preferably 75 μm and more preferably 50 μm. If the average thickness of the insulating film 11a is less than the lower limit, the insulation between the conductor 10 and the shield layer 20 may be insufficient. On the other hand, if the average thickness of the insulating film 11a exceeds the upper limit, there is a risk that the requirement for downsizing of the electronic device is violated.

  The material for the conductor holding adhesive layer 11b is not particularly limited as long as it is non-conductive and can be bonded to the pair of insulating films 11a. For example, epoxy resin, polyimide, polyester, phenol resin, polyurethane, acrylic Various resin-based adhesives such as resins, melamine resins, and polyamideimides can be used. Among them, a thermoplastic resin that can be firmly bonded to the insulating film 11a by being remelted is preferable, and among these thermoplastic resins, a polyester excellent in moldability, insulation, and the like is preferable.

  The lower limit of the average thickness (average distance between the conductor 10 and the insulating film 11a) of the conductor holding adhesive 11b in the region overlapping with the conductor 10 in plan view is preferably 5 μm and more preferably 10 μm. On the other hand, the upper limit of the average thickness is preferably 100 μm, and more preferably 50 μm. There exists a possibility that the adhesive strength of the some conductor 10 and the insulating film 11a may become inadequate that the said average thickness is less than the said minimum. Conversely, if the average thickness exceeds the upper limit, the shielded flexible flat cable may be unnecessarily thick.

(Open hole)
The flat cable body 1 has an opening 12 for forming a folded structure of the ground wire 10G. The opening 12 includes a gap 12a at a position before the ground wire 10G and the insulating layer 11 are folded back, and a cavity 12b located on the lower surface side of the gap 12a. The cavity 12b of the opening 12 has a rectangular shape whose one side is substantially parallel to the longitudinal direction of the flat cable body 1 in plan view. The upper surface of the cavity 12b of the opening 12 is constituted by the insulating layer 11 on the upper surface side of the conductor 10 excluding the ground wire 10G, and the lower surface side of the cavity 12b of the opening 12 is formed on the flat cable body 1. It is a surface opening.

  The length of one side in the longitudinal direction of the flat cable body 1 of the cavity 12b of the opening 12 is substantially equal to the average length of the gap 12a. Further, the length of one side in the width direction of the flat cable body 1 of the cavity 12b of the opening 12 is not particularly limited. For example, as shown in FIG. 1, it substantially matches the entire width of the region where the plurality of conductors 10 are disposed. be able to. The conductor 10 and the shield layer 20 are preferably insulated by an insulating member. For example, it is possible to insulate between the conductor 10 and the shield layer 20 by closing the cavity 12b of the opening 12 using an insulating adhesive tape as an insulating member.

<Shield tape>
The shield tape 2 covers the flat cable body 1. As shown in FIG. 3, the shield tape 2 may be disposed so as to cover the entire circumference of the flat cable body 1 in a cross-sectional view perpendicular to the length direction of the flat cable body 1. You may arrange | position so that the flat cable main body 1 may be pinched | interposed with the shield tape 2. FIG. Moreover, the shield tape 2 may coat | cover all the surfaces of the flat cable main body 1, and may coat | cover a part of the surface.

  The shield tape 2 has a shield layer 20 and an adhesive layer 21 laminated on the shield layer 20 on the flat cable body 1 side.

(Shield layer)
The material of the shield layer 20 is not particularly limited as long as it has conductivity, and examples thereof include metal foils such as aluminum and copper, metal vapor deposition films, conductive woven fabrics, and conductive nonwoven fabrics.

  The lower limit of the average thickness of the shield layer 20 is preferably 0.05 μm, and more preferably 0.08 μm. On the other hand, the upper limit of the average thickness of the shield layer 20 is preferably 0.2 mm, and more preferably 0.1 mm. If the average thickness of the shield layer 20 is less than the lower limit, the shielding effect may be insufficient. On the contrary, if the average thickness of the shield layer 20 exceeds the upper limit, the flexibility of the shielded flexible flat cable may be insufficient or the electronic device may be downsized.

(Adhesive layer)
The adhesive layer 21 is laminated on the flat cable body 1 side of the shield layer 20. The adhesive layer 21 may be laminated on the entire surface of the shield layer 20 in contact with the insulating layer 11 as shown in FIG. 3, but as long as the adhesive strength can be ensured, the adhesive layer 21 is one surface of the shield layer 20 in contact with the insulating layer 11. It may be laminated on the part.

  The adhesive layer 21 is non-conductive. The adhesive constituting the adhesive layer 21 is not particularly limited as long as it is non-conductive, but can be made of the same material as the conductor holding adhesive layer 11b.

  The lower limit of the average thickness of the adhesive layer 21 is preferably 1 μm and more preferably 3 μm. On the other hand, the upper limit of the average thickness of the adhesive layer 21 is preferably 20 μm and more preferably 10 μm. There exists a possibility that the adhesive force of the insulating layer 11 and the shield layer 20 may become inadequate that the average thickness of the said adhesive bond layer 21 is less than the said minimum. On the other hand, if the average thickness of the adhesive layer 21 exceeds the upper limit, the nonconductive adhesive easily enters between the ground wire 10G and the shield layer 20, and the ground wire 10G and the shield layer 20 are electrically connected. May not be fully contacted.

<Uneven sheet>
The uneven sheet 3 is disposed between the plurality of folded ground wires 10 </ b> G and the insulating layer 11 of the flat cable body 1. Specifically, the concavo-convex sheet 3 is disposed on the surface of the insulating layer 11 before the ground line 10G is folded so that the folded ground line 10G is positioned on the upper surface of the concavo-convex sheet 3. Therefore, the concavo-convex sheet 3 is in contact with the insulating layer 11 provided with the concavo-convex sheet 3 and the insulating layer 11 folded together with the ground wire 10G.

  The concavo-convex sheet 3 has concavo-convex portions on the folded ground line 10G side. Further, the concavo-convex sheet 3 is arranged so that the folded ground wire 10 </ b> G goes over one or more convex portions of the concavo-convex sheet 3. In FIG. 1, the ground line 10 </ b> G passes over three convex portions.

  The concavo-convex sheet 3 is not particularly limited as long as it has concavo-convexity, but a mesh-like sheet and a sheet having an embossed surface are preferable. Such a mesh-like sheet and a sheet having an embossed surface are relatively inexpensive, and the manufacturing cost can be further reduced. Further, even when the ground line 10G is displaced when the ground line 10G is folded back, a convex portion can be formed on the exposed part of the ground line.

  The size of the concavo-convex sheet 3 in a plan view can be a size that overlaps a part of the ground line exposed portion, but a size that overlaps the whole ground line exposed portion is preferable.

  As a minimum of the average height of the convex part of the above-mentioned uneven sheet 3, 3 micrometers is preferred and 5 micrometers is more preferred. On the other hand, as an upper limit of the average height of the convex part of the said uneven | corrugated sheet 3, 20 micrometers is preferable and 10 micrometers is more preferable. When the average height of the convex portions of the concavo-convex sheet 3 is less than the lower limit, the height of the convex portion of the ground line 10G formed along this is lowered, so that the contact between the ground line 10G and the shield layer 20 is reduced. Resistance may increase. On the other hand, if the average height of the convex portions of the concavo-convex sheet 3 exceeds the upper limit, the step between the convex portions and the concave portions becomes too large, and it may be difficult to form the convex portions of the ground line 10G.

  As a minimum of the average space | interval of the convex part of the said uneven | corrugated sheet 3, 0.5 mm is preferable and 1 mm is more preferable. On the other hand, the upper limit of the average interval between the convex portions of the concavo-convex sheet 3 is preferably 5 mm, and more preferably 4 mm. If the average interval between the convex portions of the concavo-convex sheet 3 is less than the lower limit, it may be difficult to form the convex portions of the ground wire 10G. On the other hand, if the average interval between the convex portions of the concavo-convex sheet 3 exceeds the above upper limit, the number of convex portions of the ground line 10G decreases, so that the contact resistance between the ground line 10G and the shield layer 20 may increase.

  The uneven sheet 3 may include an adhesive layer on the flat cable body 1 side. Thus, when the uneven sheet 3 includes the pressure-sensitive adhesive layer, the uneven sheet 3 can be relatively easily fixed to the surface of the insulating layer 11 by the pressure-sensitive adhesive layer. For this reason, when the shield layer 20 is disposed in the production of the shielded flexible flat cable, the uneven sheet 3 is hardly displaced. For this reason, the convex part of 10 G of ground lines can be formed more reliably. As an adhesive which comprises the said adhesive layer, an acrylic adhesive, a polyurethane-type adhesive, a polyester-type adhesive, etc. are mentioned, for example.

[Method for manufacturing shielded flexible flat cable]
The manufacturing method of the said flexible flat cable with a shield is provided with a flat cable main body formation process, a ground wire exposure process, a convex part formation process, a shield tape arrangement process, and a thermocompression bonding process. A flat cable body 1 having a plurality of conductors 10 arranged in parallel and including a ground wire 10G and an insulating layer 11 disposed around the plurality of conductors 10 by the method for manufacturing the shielded flexible flat cable, A shielded flexible flat cable comprising a shield layer 20 and a shield tape 2 having a shield layer 20 and an adhesive layer 21 laminated on the flat cable body side of the shield layer 20 is manufactured to cover the flat cable body 1. it can.

<Flat cable body formation process>
In the flat cable body forming step, the flat cable body 1 is formed.

  In this step, a plurality of conductors 10 arranged in parallel are sandwiched between a pair of insulating films 11a each having an adhesive layer laminated on opposite surfaces, and heated. By this heating, the adhesive layer laminated on each insulating film 11a is melted and integrated to form a conductor holding adhesive layer 11b, and the pair of insulating films 11a and the conductor 10 are fixed, and the flat cable body 1 Form.

  Here, of the pair of insulating films 11 a, an opening corresponding to the hollow portion of the opening 12 is formed in one insulating film 11 a in advance. Thereby, with the formation of the flat cable body 1, a recess corresponding to the hollow portion of the opening 12 is formed, and the conductor 10 including the ground wire 10G is exposed in the recess.

  The heating in the flat cable main body forming step can be performed by, for example, a hot roll at a speed of not less than 80 ° C. and not more than 200 ° C. and a speed of 0.5 m / min to 10 m / min.

<Ground line exposure process>
In the ground wire exposing step, the ground wire 10G of the flat cable body 1 is partially exposed on the surface of the flat cable body 1.

  This step can be performed, for example, by the following procedure. First, the ground wire 10G exposed in the recess is cut from the lower surface side to the upper surface side of the flat cable body 1 at one end thereof together with the insulating layer 11 laminated on the upper surface side of the ground wire 10G. In addition, the insulating layer 11 laminated on the upper surface side of the exposed ground wire 10G is cut along the longitudinal direction of the flat cable body 1 so as to be flush with the side surface of the ground wire 10G. The insulating layer 11 is cut on each of the two side surfaces of the ground line 10G. Next, the cut ground line 10G and the insulating layer 11 laminated on the upper surface side of the ground line 10G are folded back to the upper surface side. By folding back in this way, the ground wire 10G is partially exposed on the surface of the flat cable body 1.

<Projection forming step>
In the convex portion forming step, one or a plurality of convex portions are formed on the exposed portion of the ground line of the flat cable body 1.

  Specifically, first, the concavo-convex sheet 3 is disposed between the folded ground line 10 </ b> G and the insulating layer 11. Next, the ground wire 10G and the insulating layer 11 are pressure-bonded in a state where the uneven sheet 3 is sandwiched. By this pressing, the folded ground wire 10G is pressed against the concavo-convex sheet 3, thereby forming a convex portion on the folded ground wire 10G. In addition, this pressurization can be performed using the pressurization in the thermocompression bonding process mentioned later.

<Shield tape placement process>
In the shield tape arranging step, the shield tape 2 is arranged on the surface side of the flat cable body 1 so as to cover the exposed portion of the ground line. The shield tape 2 is arranged so that the shield adhesive layer 21 is on the flat cable body 1 side. The shield adhesive layer 21 is non-conductive.

<Thermocompression process>
In the thermocompression bonding step, the flat cable body 1 and the shield tape 2 are thermocompression bonded.

  The thermocompression bonding can be performed using, for example, a heating laminator equipped with a heating roller, a heating press machine, or the like. The specific heating temperature in the thermocompression bonding step can be set to 50 ° C. or more and 200 ° C. or less, for example. Moreover, as a pressurization load in a thermocompression-bonding process, it is 0.1 MPa or more and 5 MPa or less, for example, As a pressurization time, it is 1 second or more and 60 seconds or less, for example.

  The adhesive layer 21 is melted by the thermocompression bonding, and the convex portion formed on the ground wire 10G penetrates the adhesive layer 21 and is crimped to the shield layer 20, so that the ground wire 10G and the shield layer 20 are electrically connected. Is done.

〔advantage〕
In the shielded flexible flat cable, the ground wire 10G exposed on the surface of the flat cable body 1 has a convex portion. The protrusions are brought into close contact with the shield layer 20 by pressing with the shield tape, so that the ground wire 10G and the shield layer 20 are electrically connected stably. Therefore, the flexible flat cable with shield does not need to connect the ground wire 10G and the shield layer 20 with the adhesive layer 21, and can make the adhesive layer 21 non-conductive. For this reason, since the said flexible flat cable with a shield does not need to thicken the adhesive bond layer 21 in consideration of electroconductivity, the application quantity of an adhesive agent can be made comparatively small. Therefore, coupled with the fact that the cost per unit amount of the non-conductive adhesive is lower than the cost of the conductive adhesive, the flexible flat cable with shield has a lower manufacturing cost than the case where the conductive adhesive layer is used. Can be reduced.

  Moreover, the manufacturing method of the said shielded flexible flat cable can manufacture the shielded flexible flat cable which is excellent in manufacturing cost.

[Other Embodiments]
The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is not limited to the configuration of the embodiment described above, but is defined by the scope of the claims, and is intended to include all modifications within the meaning and scope equivalent to the scope of the claims. The

  In the above embodiment, the case where the insulating layer of the flat cable main body has a pair of insulating films and a conductor holding adhesive layer disposed between the pair of insulating films has been described. The layer structure is not limited to this. Examples of the configuration of the other insulating layer include a configuration in which a plurality of conductors are sandwiched between a pair of insulating films, and a configuration in which the plurality of conductors are covered only with a conductor holding adhesive layer.

  The shield tape may further have a resin layer on the surface of the shield layer opposite to the adhesive layer. Thus, peeling and corrosion of a shield layer can be prevented because a shield tape has a resin layer. Examples of the material for the resin layer include the same materials as those for the insulating film of the insulating layer.

  In the above embodiment, the case where the ground wire folding structure is provided on one side of the flat cable main body has been described, but the ground line folding structure may be provided on both sides.

  Further, the flat cable main body may have an aperture insulating layer that covers the exposed conductor other than the ground wire in the aperture. Since the flat cable main body has the hole insulating layer, the dents in the holes of the flat cable main body are reduced, and the flatness of the surface of the flat cable main body is increased, so that the adhesion to the shield tape is improved.

  In the above-described embodiment, the case where one uneven sheet is disposed between a plurality of folded ground wires and the flat cable main body surface has been described. However, an uneven sheet may be disposed for each ground line.

  Further, the uneven sheet is not an essential constituent element and can be omitted. When the uneven sheet is not used, the convex part of the ground line can be formed by a method of directly bending the folded part of the ground line.

  Moreover, although the case where the ground line has a plurality of convex portions has been described in the above embodiment, the number of the convex portions of the ground line may be one.

  Moreover, although the structure which exposes the surface of a flat cable main body by folding up a ground wire was demonstrated in the said embodiment, you may expose a ground wire on the surface by another structure. As such a configuration, for example, a filling layer may be provided on the lower surface side of the ground wire cut in a tongue shape, and the ground wire may be lifted to the upper surface side by this filling layer.

  Moreover, although the said embodiment demonstrated the case where the flat cable main body has a some ground wire, the number of ground wires may be one.

  In the above embodiment, in the method for manufacturing a shielded flexible flat cable, a method has been described in which a concave portion is provided in advance in the flat cable body forming step and the ground wire exposed in the concave portion in the ground wire exposing step is folded back to the surface side. The ground wire may be exposed on the surface of the flat cable body by a method. Examples of such a method include a method in which the ground wire is cut into a tongue shape except for one end in the longitudinal direction of the flat cable body together with the insulating layer, and the lower insulating layer is peeled off and then folded back to the upper surface side. it can.

  The shielded flexible flat cable and the manufacturing method thereof of the present invention are excellent in manufacturing cost.

DESCRIPTION OF SYMBOLS 1 Flat cable main body 2 Shield tape 3 Uneven sheet 10 Conductor 10G Ground wire 11 Insulating layer 11a Insulating film 11b Conductor holding adhesive layer 12 Opening 12a Air gap 12b Cavity 20 Shield layer 21 Adhesive layer

Claims (5)

A flat cable body having a plurality of conductors arranged in parallel and including one or a plurality of ground lines and an insulating layer disposed around the plurality of conductors, and disposed so as to cover the flat cable body A shielded flexible flat cable comprising a shield tape,
The shield tape has a shield layer and a nonconductive adhesive layer laminated on the flat cable body side of the shield layer,
One or more ground lines of the plurality of conductors and the shield layer are electrically connected,
A shield configured such that one or more ground wires of the flat cable main body are exposed on the surface of the flat cable main body in a part of the shield tape covering region, and one or more convex portions are formed on the surface side. Flexible flat cable with cable.   The one or more ground wires are cut at a part of the shield tape covering region of the flat cable body, and the cut one side is folded back to the surface side and exposed to the surface of the flat cable body. The flexible flat cable with a shield according to claim 1.   The flexible flat cable with a shield according to claim 2, further comprising an uneven sheet having unevenness on the ground line side between the folded ground line and the insulating layer.   The shielded flexible flat cable according to claim 3, wherein the uneven sheet is a mesh sheet or a sheet having an embossed surface. A flat cable body having a plurality of conductors arranged in parallel and including one or a plurality of ground lines and an insulating layer disposed around the plurality of conductors, and disposed so as to cover the flat cable body A method for producing a shielded flexible flat cable comprising a shield tape,
The shield tape has a shield layer and a non-conductive adhesive layer laminated on the shield layer,
Partially exposing the ground wire of the flat cable body to the surface of the flat cable body;
Forming one or a plurality of convex portions on the ground wire exposed portion of the flat cable body;
The step of covering the ground wire exposed part on the surface side of the flat cable body, and arranging the shield tape so that the adhesive layer is on the flat cable body side,
A method for producing a shielded flexible flat cable, comprising: thermocompression bonding the flat cable body and the shield tape.

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