JP2012033422A - Method of manufacturing flexible flat cable - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing a flexible flat cable (FFC), which enhances the reliability.SOLUTION: The method of manufacturing a FFC1 comprises a conductor arrangement process P1 of arranging a flat wire 15 for a signal conductor 10 on a flat wire 25 for a drain wire 20 in parallel and superposing a flat wire 26 for dummy use on top of the flat wire 25; a laminate process P2 of sandwiching the flat wires 15 and 25 between insulation sheets 35 and 36 so as to have part of the flat wires 15 and 25 exposed a certain length; a plating process P3 of electroplating portions where the flat wires 15 and 25 are exposed from the insulation sheets 35 and 36; a peeling process P4 of separating the flat wire 26 along with part of the insulation sheet 35; a shield arrangement process P5 of disposing a shield 40 on the insulation sheet 35 and electrically connecting the shield 40 and the flat wire 25; and an adhesion process P6 of sticking a reinforcement plate 55 to portions of the flat wires 15 and 25 exposed from the insulation sheets 35 and 36.

Description

  The present invention relates to a method for manufacturing a flexible flat cable, and more particularly to a method for manufacturing a flexible flat cable capable of manufacturing a highly reliable flexible flat cable.

  In mobile phones, personal computers, etc., flexible flat cables in which a plurality of flat wires are sandwiched between insulating sheets are used. The ends of the plurality of rectangular wires in the flexible flat cable are exposed from the insulating sheet and serve as terminals connected to a connector or the like. In general, these terminals are plated for the purpose of preventing the occurrence of rust, whiskers and the like and ensuring reliability. This plating is usually gold plating.

  Patent Document 1 below describes a plating method for the terminal portion of such a flexible flat cable. In this plating method, in a state where a plurality of flexible flat cables are connected in a long shape, a portion to be a flat wire terminal is exposed from the insulating sheet, and electric field plating is applied to the exposed portion of the flat wire. Applied. Thereafter, in a state in which the portion to be a terminal in the flat wire is plated, the portion to be the terminal is cut into individual flexible flat cables.

  By the way, in the flexible flat cable, a shield is provided so as to cover the outer peripheral surface of the insulating sheet sandwiching the flat wire, and a part of the flat wire may be used as a drain wire connected to the shield. .

  Patent Document 2 listed below describes a flexible flat cable having such a drain wire. In the production process of this flexible flat cable, a plurality of rectangular wires are arranged in parallel with a plurality of flexible flat cables connected in a long shape. Are superimposed. Then, the overlapped other flat wire is peeled off together with the insulating sheet, and the flat wire serving as the drain line is exposed from the portion where the insulating sheet is peeled off. Then, a shield is provided so as to cover the insulating sheet, and the flat wire serving as the drain line is connected to the shield at the portion where the insulating sheet is peeled off. Thereafter, the flat wire that is cut for each flexible flat cable and is in contact with the shield is used as a drain wire, and the other flat wire is used as a signal wire.

Japanese Patent Laid-Open No. 08-293214 Japanese Patent Laid-Open No. 2004-87312

  When the flexible flat cable described in Patent Document 2 is plated as in Patent Document 1, if one of the rectangular wires is peeled off together with the insulating sheet and then electroplated, the portion that becomes the terminal of the drain wire Plating can be applied to the entire side surface. However, at the time of electroplating, the flat wire serving as the signal line exposes only the portion serving as the terminal, whereas the flat wire serving as the drain wire is the portion serving as the terminal because the insulating sheet is peeled off. Other parts are also exposed. Therefore, in the plating solution, only the portion of the flat wire that becomes the signal line contacts the plating solution in contact with the plating solution, whereas the flat wire that becomes the drain wire peels off the insulating sheet in addition to the portion that becomes the terminal. The exposed part is also in contact with the plating solution. In this way, the rectangular wire serving as the drain line comes into contact with the plating solution in a larger area than the flat wire serving as the signal line, so the density of the current flowing between the flat wire serving as the drain line and the plating solution is a signal. It becomes lower than the density of the electric current which flows between the flat wire which becomes a wire, and the plating solution. Accordingly, the thickness of the plating of the terminal of the drain line becomes thinner than the thickness of the plating of the terminal of the signal line, and the terminal of the drain line may be less resistant to rust and whiskers. Therefore, the reliability of the flexible flat cable may be lowered.

  Then, an object of this invention is to provide the manufacturing method of the flexible flat cable which can manufacture a flexible flat cable with high reliability.

  The method for producing a flexible flat cable according to the present invention comprises arranging at least one signal line conductor and at least one drain line conductor in parallel, and providing a dummy conductor to the drain line conductor. Conductive wire placement step of overlapping, laminating step of sandwiching each conductive wire with a set of insulating sheets so that a part of each of the conductive wires is exposed side by side, and the conductive wires are exposed from the insulating sheet A plating step of electroplating a portion that has been removed, a peeling step of peeling off the dummy conductive wire together with a portion of the insulating sheet after the plating step, and the conductive wire in the insulating sheet from which at least a portion has been peeled off A shield is disposed on the surface opposite to the contact surface, and at the portion where the insulating sheet is peeled off, the shield and the shield are disposed. A reinforcing plate is bonded to a portion of the conductive wire exposed from the insulating sheet from the side of the insulating sheet from which the shield wire is electrically connected to the in-wire conductive wire and a part of the insulating sheet is peeled off. And an adhesion step.

  According to such a method for manufacturing a flexible flat cable, a portion of each conductive wire exposed from the insulating sheet is plated by electroplating. The portion to be plated is a portion that becomes a terminal of the flexible flat cable. At this time, since a part of each conductor wire is exposed for a certain length, the set of the conductor wire for the drain wire and the dummy conductor wire and the conductor wire for the signal wire, which are overlapped with each other, are in contact with the plating solution. The area to be applied does not change so much, and the density of current flowing between each conductor and the plating solution does not change so much. For this reason, the dispersion | variation in the thickness of the plating adhering to the conducting wire for signal lines and the thickness of the plating adhering to the conducting wire for drain lines can be suppressed. After that, when the dummy conductor is peeled off, the portion of the drain wire that is in contact with the dummy conductor is exposed without being plated, but the exposed portion is reinforced. Since the plate is bonded, rust and whiskers can be prevented. In this way, variation in plating thickness is suppressed between the terminal of the signal line and the terminal of the drain line, and the non-plated portion of the terminal is protected by the reinforcing plate, so that a highly reliable flexible flat A cable can be manufactured.

  Moreover, in the manufacturing method of the said flexible flat cable, it is preferable that the said conducting wire is a flat wire.

  Moreover, it is preferable to further include a cutting step of cutting each of the conducting wires in the portion where the conducting wires are exposed from the insulating sheet after the plating step in the method of manufacturing the flexible flat cable.

  According to such a manufacturing method of a flexible flat cable, the conducting wire which becomes a some flexible flat cable is connected at the time of a plating process. That is, plating is performed in a long state before the conductor is cut. Therefore, a plating process can be performed continuously and a flexible flat cable can be manufactured efficiently.

  Or before the said plating process in the manufacturing method of the said flexible flat cable, it is preferable to further provide the cutting process which cut | disconnects each said conducting wire in the part which the said conducting wire is exposed from the said insulating sheet.

  According to such a method for manufacturing a flexible flat cable, plating is performed in a state where each conductive wire is cut during the plating step. Therefore, the cut surface of the conductive wire can be plated, and the generation of rust and whiskers can be further prevented, and a highly reliable flexible flat cable can be manufactured.

  As described above, according to the present invention, a method for manufacturing a flexible flat cable capable of manufacturing a flexible flat cable with high reliability is provided.

It is a top view which shows the flexible flat cable manufactured by the manufacturing method of the flexible flat cable which concerns on 1st Embodiment of this invention. It is a figure which shows the structure of the cross section in the II-II line | wire of FIG. It is a figure which shows the structure of the cross section in the III-III line of FIG. It is a flowchart which shows the manufacturing method of the flexible flat cable of FIG. It is a figure which shows the mode after a conducting wire arrangement | positioning process. It is a figure which shows the mode of a lamination process. It is a figure which shows the mode after a lamination process. It is a figure which shows the mode of a peeling process. It is a figure which shows the mode after a shield arrangement | positioning process. It is a figure which shows the mode after an adhesion process. It is a flowchart which shows the manufacturing method of the flexible flat cable which concerns on 2nd Embodiment of this invention.

  Hereinafter, a preferred embodiment of a method for producing a flexible flat cable (hereinafter referred to as FFC) according to the present invention will be described in detail with reference to the drawings.

(First embodiment)
FIG. 1 is a plan view showing an FFC manufactured by the FFC manufacturing method according to the first embodiment of the present invention, showing a cross-sectional structure taken along line II-II in FIG. 1, and FIG. It is a figure which shows the structure of the cross section in the III-III line of FIG.

  As shown in FIGS. 1 and 2, the FFC 1 includes a plurality of signal lines 10, a plurality of drain lines 20, and a pair of insulating sheets that sandwich each signal line 10 and expose a part of each drain line 20. 31, 32, a shield 40 provided on one surface of the insulating sheet 31, and a reinforcing plate 50 are provided as main components.

  The pair of insulating sheets 31 and 32 are each composed of a strip-shaped resin sheet having flexibility. As shown in FIG. 1, both end edges 34 in the length direction of the insulating sheet 31 are formed in a straight line, and both end edges in the length direction of the insulating sheet 32 are also end edges 34 of the insulating sheet 31. It is formed in a straight shape like Moreover, although each insulation sheet 31 and 32 is the mutually same external shape, the insulation sheet 31 is partially peeled off as FIG. 2 shows, and the defect | deletion part 33 is formed.

  The material of the insulating sheets 31 and 32 having flexibility is not particularly limited, and examples thereof include resins such as polyethylene terephthalate, polyethylene naphthalate, polyimide, polyvinyl chloride, and polypropylene. Terephthalate is preferred. Moreover, the adhesive agent which is not illustrated is apply | coated to the surface where a pair of insulating sheet 31 and 32 opposes insulating sheets.

  Each signal line 10 is composed of a rectangular wire as a conducting wire, and is arranged in parallel so as to be parallel to each other. Examples of the material of the signal line 10 include metals such as copper (Cu), nickel (Ni), and aluminum (Al). Further, the signal line 10 may be a conductive wire coated with a metal wire by plating. For example, the signal line 10 may be a flat wire in which copper is coated with nickel plating.

  Each drain line 20 is formed of a rectangular wire as a conducting wire similarly to the signal line 10, and is disposed between the signal line 10 and the signal line 10. Examples of the material of the drain line 20 include materials that can be used for the signal line 10. Similarly to the signal line 10, the drain line 20 uses a conductive wire covered with a metal wire by plating. be able to.

  The signal line 10 is sandwiched between a pair of insulating sheets 31 and 32 and is fixed by an adhesive (not shown) applied to the surfaces of the insulating sheets 31 and 32. Then, both ends of the signal line 10 are exposed from both edges 34 of the insulating sheet 31 and both edges of the insulating sheet 32, and a portion exposed from the edge of the signal line 10 is exposed. Terminal 11 is provided. Further, the drain line 20 is sandwiched between the pair of insulating sheets 31 and 32, but one surface of the drain line 20 is exposed from the missing portion 33 of the one insulating sheet 31. Similarly to the signal line 10, both end portions of the drain line 20 are exposed from both end edges 34 of the insulating sheet 31 and both end edges of the insulating sheet 32. A portion exposed from the edge is a terminal 21.

  Moreover, as shown in FIG. 3, both terminals 11 of the signal line 10 are plated 12 on all side surfaces. In other words, the portions of the signal line 10 exposed from the recesses of the insulating sheets 31 and 32 are plated 12 over all four side surfaces of the flat wire. The metal used for the plating 12 applied to the terminal 11 of the signal line 10 is preferably a metal having excellent corrosion resistance, and typically gold is used.

  Further, both terminals 21 of the drain wire 20 are plated 22 on all the side surfaces except the side surface on the insulating sheet 31 side. That is, the part exposed from the edge of the insulating sheets 31 and 32 in the drain wire 20 is plated 22 over all three side surfaces except for the insulating sheet 31 side among the four side surfaces of the flat wire. . The metal used for the plating 22 of the terminal 21 of the drain line 20 is the same metal as the metal used for the plating 12 of the terminal 11 of the signal line 10.

  The plating 12 applied to the end of the signal line 10 and the plating 22 applied to the end of the drain line 20 have substantially the same thickness.

  Thus, the terminal 11 of the signal line 10 and the terminal 21 of the drain line 20 exposed from the respective edges of the insulating sheets 31 and 32 are used as FFC terminals.

  As shown in FIGS. 1 and 3, a reinforcing plate 50 is provided so as to overlap the edge 34 of the insulating sheet 31, the terminal 11 of each signal line 10, and the terminal 21 of the drain line 20. Yes. The reinforcing plate 50 is made of a substantially rectangular plate-like resin and has a width similar to that of the insulating sheet 31 and completely covers the terminal 11 of each signal line 10 and the terminal 21 of the drain line 20. It is about the length. Further, the reinforcing plate 50 has a higher strength than the insulating sheets 31 and 32 and is configured to be more difficult to bend than the insulating sheets 31 and 32.

  One surface of the reinforcing plate 50 is bonded and fixed to the insulating sheet 31 with an adhesive (not shown), and the insulating sheet 31 is connected to the terminal 11 of the signal line 10 and the terminal 21 of the drain line 20. It is bonded from the side with an adhesive (not shown). Accordingly, the surface of the terminal 21 of the drain wire 20 that is not plated 22 is bonded to the reinforcing plate 50, and the side surface of the terminal 21 of the drain wire 20 is covered with the plating 22 and the reinforcing plate 50. Yes. Thus, the terminal 11 of each signal line 10 and the terminal 21 of each drain line 20 are reinforced by the reinforcing plate 50, and the edge 51 of the reinforcing plate 50 is used as the connector edge of the FFC 1.

  Examples of the resin constituting the reinforcing plate 50 include resins that can be used for the insulating sheets 31 and 32. Among them, polyethylene terephthalate is preferable from the viewpoint of high strength.

  As shown in FIGS. 1 and 2, a shield 40 is provided on the opposite side of the insulating sheet 31 from the signal line 10 and the drain line 20.

  As shown in FIG. 2, the shield 40 includes a base film 41, a metal layer 42, and an adhesive layer 43.

  As shown in FIGS. 1 and 2, the base film 41 is composed of a strip-shaped resin film. The base film 41 has the same width as the insulating sheet 31, and the edge 34 of the insulating sheet 31 is exposed from the base film 41 when the base film 41 and the insulating sheet 31 are overlapped. It is said to be long. Although it does not specifically limit as resin of such a base film 41, Resin similar to resin which can be used for the insulating sheets 31 and 32 can be mentioned.

  A metal layer 42 is provided on one surface of the base film 41. The metal layer 42 is provided over the entire surface of the base film 41 by attaching a metallic foil to the base film 41 or by depositing metal on the base film 41. Although it does not specifically limit as a metal which comprises the metal layer 42, The metal which can be used for the rectangular wire which comprises the signal wire | line 10 and the drain wire 20 can be mentioned.

  An adhesive layer 43 is provided on the side opposite to the base film 41 side of the metal layer 42. The adhesive layer 43 is made of a conductive adhesive. The shield 40 is fixed to the insulating sheet 31 by bonding the adhesive layer 43 to the insulating sheet 31. Further, the adhesive layer 43 is in contact with one surface of the drain wire 20 from the defect portion 33 of the insulating sheet 31, and the metal layer 42 and the drain wire 20 are interposed via the adhesive layer 40 that is a conductive adhesive. Are electrically connected to each other.

  In such an FFC 1, both ends of the FFC 1 are connected to a connector or the like together with the reinforcing plate 50, a signal is propagated by the signal line 10, and the drain line 20 is connected to the ground.

  Next, the manufacturing method of FFC1 is demonstrated.

  FIG. 4 is a flowchart showing a method for manufacturing the FFC 1 of FIG. As shown in FIG. 4, the FFC 1 manufacturing method includes a conductor arrangement in which a conductor for the signal line 10 and a conductor for the drain line 20 are juxtaposed and a dummy conductor is superimposed on the conductor for the drain line 20. Step P1, a laminating step P2 for sandwiching each conductive wire with a set of insulating sheets so that a part of each conductive wire is exposed, and a plating step for electroplating a portion where each conductive wire is exposed from the insulating sheet P3, a peeling process P4 for peeling off the dummy conductive wire together with a part of the insulating sheet, and a shield 40 is arranged on the side opposite to the conductive wire side in the partially peeled insulating sheet, and the insulating sheet is peeled off. The shield arrangement step P5 for electrically connecting the shield 40 and the conductor for the drain wire 20 and the insulating sheet side from which a part has been peeled off A bonding process P6 for bonding the reinforcing plate 50 to a portion of each conductive wire exposed from the insulating sheet, a slit process P7 for cutting both end portions in the width direction of each insulating sheet along the longitudinal direction, In a portion where the conducting wire is exposed from the insulating sheet, a cutting process P8 for cutting each conducting wire is provided as a main configuration.

(Conducting wire placement process P1)
First, as shown in FIG. 5, the rectangular wire 15 as the conducting wire for the signal line 10 and the rectangular wire 25 as the conducting wire for the drain wire 20 are juxtaposed side by side, and a dummy conducting wire is arranged. The flat wire 26 is superimposed on one surface of the flat wire 25. The dummy rectangular wire 26 has the same configuration as the rectangular wire 25 for the drain line 20. At this time, when there are a plurality of rectangular wires to be the drain lines 20, they are overlapped so that the directions of the rectangular wires 25 for the drain lines 20 and the dummy rectangular wires 26 are directed in the same direction. The rectangular wire 25 for the drain line 20 and the rectangular wire 26 for the dummy may be overlapped, and then the rectangular wire 15 for the signal line 10 and the rectangular wire 25 for the drain line 20 may be arranged in parallel. The rectangular wire 15 for the signal line 10 and the rectangular wire 25 for the drain line 20 may be arranged in parallel, and then the rectangular wire 25 for the drain line 20 and the dummy rectangular wire 26 may be overlapped.

(Lamination process P2)
Next, as shown in FIG. 6, the pair of the rectangular wire 15 for the signal line 10 and the rectangular wire 25 for the drain line 20 and the rectangular flat wire 26 are sandwiched between a pair of insulating sheets 35 and 36. . The insulating sheet 35 is a sheet in which the insulating sheet 31 that is the insulating sheet 31 shown in FIG. 1 is connected in a long shape, and the insulating sheet 36 is a sheet in which the insulating sheet that is used as the insulating sheet 32 is connected in a long shape. . The insulating sheet 35 is provided with an opening 37 whose part is the edge 34 of the insulating sheet 31, and the insulating sheet 36 is similarly provided with an opening 38. It should be noted that the opening 37 of the insulating sheet 35 has slight cuts in portions corresponding to both edges in the width direction of the dummy flat wire 26 after sandwiching the respective flat wires. It is preferable from the viewpoint of easily performing the process P4. Further, an adhesive (not shown) is applied to the surfaces of the insulating sheets 35 and 36 facing each other.

  In the laminating process P2, a set of the flat wire 15 for the signal line 10 and the flat wire 25 for the drain wire 20 and the flat wire for dummy 26 is sandwiched between a pair of insulating sheets 35 and 36, not shown. Laminate with a thermal laminator. Thus, as shown in FIGS. 6 and 7, by the adhesive applied to the respective insulating sheets 35 and 36, the flat wire 15 for the signal line 10, the flat wire 25 for the drain line 20, and the dummy wire are used. A pair with the flat wire 26 is sandwiched and fixed between the insulating sheets 35 and 36, and the flat wire 15 for the signal line 10 and the flat wire 25 for the drain wire 20 through the openings 37 and 38, and The flat rectangular wire 26 is exposed side by side for a certain length.

(Plating process P3)
Next, the flat wire 15 for the signal line 10, the flat wire 25 for the drain line 20, and the dummy flat wire 26 are exposed from the insulating sheets 35 and 36 in the openings 37 and 38. Is electroplated. In the plating process P3, the flat wire 15 for the signal line 10, the flat wire 25 for the drain wire 20, and the flat wire 26 for the dummy are in contact with the plating solution in the openings 37 and 38. At this time, the current flowing between the flat wire 15 for the signal line 10 and the plating solution, and the current flowing between the set of the flat wire 25 for the drain line 20 and the dummy flat wire 26 and the plating solution, To be equal. The portions of the flat wire 15 for the signal line 10, the flat wire 25 for the drain line 20, and the flat wire 26 for the dummy that are exposed from the openings 37 and 38 are plated. However, the flat wire 25 for the drain wire 20 and the flat wire 26 for the dummy are overlapped so that the portions that are in contact with each other do not come into contact with the plating solution, so that plating is not performed.

(Peeling process P4)
Next, as shown in FIG. 8, the dummy rectangular wire 26 is peeled off together with a part of the insulating sheet 35. Thus, the defect portion 33 is formed in the insulating sheet 35, and the flat wire 25 for the drain line 20 is exposed from the defect portion 33. As described above, since the portion of the flat wire 25 for the drain wire 20 that is in contact with the dummy flat wire 26 is not plated, the flat wire 25 is exposed from the defect portion 33, And the part exposed from the insulating sheet 35 side in the opening 37 is not plated in the plating step P3.

  In this step, as described above, when the opening 37 of the insulating sheet 35 is slightly cut at portions corresponding to both edges in the width direction of the dummy rectangular wire 26, the cut is the starting point. Thus, a part of the insulating sheet 35 can be easily peeled off, and the defect portion 33 can be easily formed. Further, when there are a plurality of dummy rectangular wires 26 as in the present embodiment, it is possible to peel off the dummy rectangular wires 26 at the same time from the viewpoint of efficiently peeling off the dummy rectangular wires 26. Peeling at different timings is preferable from the viewpoint of reducing the load on the flat wire 15 that becomes the signal line 10, the flat wire 25 that becomes the drain line 20, and the insulating sheets 35 and 36. Note that FIG. 8 shows a state where the first of the rectangular wires 25 to be the plurality of drain lines 20 is peeled off.

(Shield placement process P5)
Next, the shield 40 is disposed. The shield 40 is disposed between the openings 37 on the insulating sheet 35. At this time, the shield 40 is pressed onto the insulating sheet 35 so that the adhesive layer 43 of the shield 40 is bonded to the flat wire 25 serving as the drain wire 20 through the defect portion 33. Thus, as shown in FIG. 9, the shield 40 is provided on the insulating sheet 35.

(Adhesion process P6)
Next, the reinforcing plate 55 in which two reinforcing plates 50 are connected is bonded. An adhesive agent (not shown) is applied to the reinforcing plate 55, and the reinforcing plate 55 is bonded to the insulating sheet 35 so as to cover the opening 37. At this time, the reinforcing plate 55 is bonded to the insulating sheet 35 with an adhesive applied to the reinforcing plate 55, and is bonded to the flat wire 15 for the signal line 10 and the flat wire 25 for the drain line 20. The flat wire 25 for the drain wire 20 is covered with a reinforcing plate 55 in the opening 37 where the plating is not performed in the plating step P3. Thus, as shown in FIG. 10, the opening 37 is covered with the reinforcing plate 55.

(Slit process P7)
Next, both end portions in the width direction of the respective insulating sheets 35 and 36 are cut along the longitudinal direction. Specifically, as shown in FIG. 10, it is defined between the flat wire at the end (in this embodiment, the flat wire 15 for the signal line 10) and both ends of the insulating sheets 35 and 36 in the width direction. The insulating sheets 35 and 36 are cut along the line L1. In this way, the insulating sheets 35 and 36 on the sides of the openings 37 and 38 are cut off, and the insulating sheets 35 and 36 that are connected to each other in a long shape are formed into a plurality of insulating sheets 31 and 32, respectively. And the edge of the insulating sheet 32 is formed.

(Cutting process P8)
Next, at the portions where the rectangular wire 15 for the signal line 10 and the rectangular wire 25 for the drain line 20 are exposed from the insulating sheets 35 and 36, the respective rectangular wires are cut. Specifically, each of the rectangular wires 15 and 25 and the insulating sheets 35 and 36 and the insulating sheets 35 and 36 along the line L2 of FIG. Then, the reinforcing plate 55 is cut. In this way, FFC1 shown in FIG. 1 is obtained.

  As described above, according to the manufacturing method of the FFC 1 in the present embodiment, the portions where the flat wires 15 and 25 are partially exposed from the insulating sheets 35 and 36 are plated by electroplating. This portion to be plated is a portion that becomes a terminal of the FFC 1. At this time, since a part of each of the rectangular wires 15 and 25 is exposed for a certain length, a set of the rectangular wire 25 for the drain wire 20 and the dummy rectangular wire 26 that are overlapped with each other and the signal wire 10 are used. The area of the rectangular wire 15 in contact with the plating solution does not change so much, and the density of the current flowing between each rectangular wire and the plating solution does not change so much. For this reason, the dispersion | variation in the thickness of the plating adhering to the flat wire 15 for the signal line 10 and the plating thickness adhering to the flat wire 25 for the drain line 20 can be suppressed. Thereafter, the dummy flat wire 26 is peeled off, so that the portion of the flat wire 25 for the drain wire 20 that is in contact with the dummy flat wire 26 is exposed without being plated. Since the reinforcing plate 50 is adhered to the exposed portion, rust, whiskers, and the like can be prevented. In this way, variation in plating thickness is suppressed between the terminal 11 of the signal line 10 and the terminal 21 of the drain line 20, and the non-plated portion of the terminal is protected by the reinforcing plate 50. A highly reliable FFC 1 can be manufactured.

  Moreover, in this embodiment, in the plating process P3, the rectangular wires 15 and 25 which become a plurality of FFCs 1 are connected. That is, plating is performed in a long state before the flat wires 15 and 25 are cut. Therefore, the plating process can be continuously performed, and the FFC 1 can be manufactured efficiently.

(Second Embodiment)
Next, a second embodiment of the present invention will be described in detail with reference to FIG. In addition, about the component which is the same as that of 1st Embodiment, or an equivalent component, the overlapping description is abbreviate | omitted except the case where it attaches | subjects the same referential mark and demonstrates in particular. Note that the FFC manufactured in the present embodiment is substantially the same as the FFC 1 manufactured in the first embodiment, and thus the description of the configuration of the FFC is omitted unless otherwise specified. FIG. 11 is a flowchart showing an FFC manufacturing method according to the second embodiment of the present invention.

  As shown in FIG. 11, the FFC manufacturing method of the present embodiment is different from the FFC manufacturing method of the first embodiment in that the slitting process P7 and the cutting process P8 are performed before the plating process P3.

  First, in the same manner as in the first embodiment, the conducting wire arranging process P1 is performed, and then the laminating process P2 is performed.

  And in this embodiment, the slit process P7 is performed after the lamination process P2. In the slit process P7, the insulating sheets 35 and 36 are cut along a line corresponding to the line L1 in FIG. 10 in the same manner as in the first embodiment. Therefore, the insulating sheets 35 and 36 on the sides of the openings 37 and 38 are cut off, and the insulating sheets 35 and 36 connected to each other in a long shape are separated into a plurality of insulating sheets 31 and 32.

  And the cutting process P8 is performed after the slit process P7. In the cutting step P7 of the present embodiment, portions where the flat wire 15 for the signal line 10, the flat wire 25 for the drain wire 20, and the flat wire 26 for dummy are exposed from the insulating sheets 35 and 36. In FIG. 10, each rectangular wire is cut along a line corresponding to the line L2 in FIG. Specifically, the rectangular wires 15 and 25 pass between the end edge 34 of the insulating sheet 31 and the end edge 34 of the next insulating sheet 31 and extend in a direction perpendicular to the longitudinal direction of the insulating sheet 35. , 26 is cut. In this way, the rectangular wires 15 and 25 are used as the signal line 10 and the drain line 20, respectively, and are semi-finished products of respective FFCs.

  Next, the plating process P3 is performed. In the plating step, the portions where the flat wire of the drain wire 20 and the flat wire for the dummy and the flat wire of the signal wire 10 are exposed from the insulating sheets 31 and 32 in each FFC semi-finished product are plated. In contact with the solution, a current is passed between the flat wire of the drain wire 20 and the flat wire for the dummy, and between the flat wire of the signal wire 10 and the plating solution. At this time, the current flowing between the flat wire of the drain line 20 and the dummy flat wire and the plating solution is made equal to the current flowing between the flat wire of the signal line 10 and the plating solution. . In this way, plating is applied to portions where the rectangular wire of the signal line 10, the rectangular wire of the drain line 20, and the dummy rectangular wire are exposed from the insulating sheets 31 and 32.

  Next, the peeling process P4 is performed. In the peeling step P <b> 4 of the present embodiment, the dummy rectangular wire is peeled off together with a part of the insulating sheet 31 in each FFC semi-finished product. Thus, the defect portion 33 is formed in the insulating sheet 31 and the rectangular wire for the drain line 20 is exposed from the defect portion 33.

  Next, the shield arrangement process P5 is performed. The shield 40 is disposed on the insulating sheet 31 between the recesses 34 formed at both ends of the insulating sheet 31.

  Next, the bonding process P6 is performed. In the bonding process P6 of the present embodiment, the end of the flat wire of the signal line 10 and the end of the flat wire of the drain line 20 and the edge 51 of the reinforcing plate 50 are aligned in each FFC semi-finished product. In this manner, the reinforcing plate 50 is bonded so as to cover the concave portion 34 of the insulating sheet 31. In this way, an FFC substantially similar to the FFC 1 shown in FIG. 1 is obtained.

  According to the FFC manufacturing method of the present embodiment, in the plating step P3, plating is performed in a state where the respective rectangular wires 15, 25, 26 are cut. Therefore, it is possible to perform plating on the cut surface of the flat wire, to further prevent the generation of rust and whiskers, and to manufacture a highly reliable flexible flat cable.

  The present invention has been described above by taking the first and second embodiments as examples, but the present invention is not limited to these.

  For example, in the first and second embodiments, the FFC includes a plurality of signal lines 10 and a plurality of drain lines 20, but the present invention is not limited to this, and at least one signal line and It suffices to have at least one drain line.

  In the first and second embodiments, the signal lines 10 and the drain lines 20 have been described as examples of rectangular wires, but the present invention is not limited to this. For example, the drain wire 20 may be configured by a conductive wire having another shape having a flat surface on a part of the side surface. In this case, the dummy conducting wire may be superimposed on the plane on the side surface of the drain wire 20.

  Furthermore, in the first and second embodiments, the shield 40 may also be provided on the insulating sheet 32. In this case, the shield 40 may be wound so as to cover the respective insulating sheets 31 and 32.

  In the first and second embodiments, the bonding process P6 may be performed between the peeling process P4 and the shield arrangement process P5.

  In the first and second embodiments, the slit process P7 may be omitted.

  In the first and second embodiments, a rectangular wire that is longer than the length of the signal line and drain line in the FFC to be manufactured is used, and in the cutting process, the signal line in the FFC that manufactures these rectangular wires is used. The length of the drain line. However, the present invention is not limited to this. Conductive wires equal in length to the signal lines and drain wires in the FFC to be manufactured are arranged in the arranging step P1, and these rectangular wires are sandwiched between the insulating sheets 31 and 32 in the laminating step. But it ’s okay. By carrying out like this, it can be made the same state as the semi-finished product of FFC after the cutting process of 2nd Embodiment.

  In the first and second embodiments, the shield 40 is composed of the base film 41, the metal layer 42, and the adhesive layer 43. However, the base film 41 is not an essential requirement. In this case, the thickness of the metal layer 42 may be increased. Furthermore, when there is no base film 41, the adhesive layer 43 may not be a conductive adhesive. In this case, the metal layer 42 may be directly connected to the flat wire for the drain line 20 by an ultrasonic welder or the like to make conduction.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the flexible flat cable which can manufacture a highly reliable flexible flat cable is provided.

1 ... Flexible flat cable (FFC)
DESCRIPTION OF SYMBOLS 10 ... Signal wire 11 ... Terminal 12 ... Plating 15 ... Flat wire for signal wires 20 ... Drain wire 21 ... Terminal 22 ... Plating 25 ... For drain wire Flat wire 26 ... Flat wire for dummy 31, 32 ... Insulating sheet 33 ... Defect 34 ... Edge 35, 36 ... Insulating sheet 37, 38 ... Opening 40 ... Shield 41 ... Base film 42 ... Metal layer 43 ... Adhesive layer 50 ... Reinforcement plate 51 ... Edge 55 ... Reinforcement plate P1 ... Conductor arrangement process P2 ... Lamination process P3 ... Plating step P4 ... Peeling step P5 ... Shield placement step P6 ... Adhesion step P7 ... Cutting step

Claims (4)

A conductor arrangement step of juxtaposing at least one signal line conductor and at least one drain line conductor, and superimposing a dummy conductor on the drain line;
A laminating step of sandwiching each conductive wire with a set of insulating sheets such that a part of each conductive wire is exposed side by side for a certain length;
A plating step of electroplating a portion where the conductive wire is exposed from the insulating sheet;
A peeling step of peeling off the dummy conductive wire together with a part of the insulating sheet after the plating step;
A shield is disposed on a surface of the insulating sheet that is at least partially peeled away from a surface that is in contact with the conductor, and the shield and the conductor for the drain wire are disposed at a portion where the insulating sheet is peeled off. And a shield arrangement process for electrically connecting
From the side of the insulating sheet that has been partially peeled off, an adhesion step of bonding a reinforcing plate to a portion exposed from the insulating sheet in each of the conductive wires;
A method for producing a flexible flat cable, comprising:   The method for manufacturing a flexible flat cable according to claim 1, wherein the conducting wire is a flat wire.   3. The flexible flat cable according to claim 1, further comprising a cutting step of cutting each of the conducting wires in a portion where the conducting wires are exposed from the insulating sheet after the plating step. Production method.   The flexible flat cable according to claim 1, further comprising a cutting step of cutting each of the conductive wires in a portion where the conductive wires are exposed from the insulating sheet before the plating step. Production method.

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