JP5287531B2 - Manufacturing method of shielded flat cable - Google Patents

Description

  The present invention relates to a method for manufacturing a shielded flat cable, and more particularly to a method for manufacturing a shielded flat cable having a low dielectric layer for adjusting characteristic impedance.

  Flat cables are widely used as internal wiring for precision electronic equipment such as various video equipment, cameras, computers, liquid crystal equipment, etc., but as these equipment become more multifunctional, noise countermeasures are required inside the equipment. In order to cope with this, the demand for a shielded cable as disclosed in Patent Document 1 is increasing.

  Also, when used as a high-speed transmission wiring cable for electronic devices connected to liquid crystal displays, plasma displays, etc., the characteristic impedance of the shielded flat cable is the same value as the impedance of the high-speed digital signal transmission / reception IC Must be set to For this reason, in Patent Document 2, a low dielectric layer is provided between an insulating film covering both surfaces of a plurality of conductors and a shield layer covering the outermost surface, and the material and thickness of the low dielectric layer are changed. It is disclosed that the characteristic impedance value of a shielded flat cable is set to a desired value.

  FIG. 5 is a diagram showing a simplified cross section of a shielded flat cable having such a low dielectric layer. The shielded flat cable 101 includes a plurality of conductors 102 and an insulating resin layer 103 that covers both surfaces of the conductors 102. A low dielectric layer 104 provided on the outer surface of the insulating resin layer 103, and a shield layer 105 covering the outer surface of the low dielectric layer 104.

JP-A-9-180547 JP 2008-198592 A

  In manufacturing the shielded flat cable shown in FIG. 5, first, the both surfaces of the conductor 102 are sandwiched between insulating resin layers 103 provided with an adhesive layer on the surface, and heat and pressure treatment is performed to continuously insulate. The resin layer 103 is laminated and bonded to the conductor 102 to produce a long product in which both sides of the conductor 102 are covered with the insulating resin layer 103.

Next, a low dielectric layer 104 having an adhesive layer provided on the surface is placed on the surface of the insulating resin layer 103, and the low dielectric layer 104 is provided on the outer surface of the pair of insulating resin layers 103 via the adhesive layer. The shield layer 105 is disposed on the outer surface of the low dielectric layer 104 by winding a shield tape prepared in advance so as to cover the low dielectric layer 104 located on both outer surfaces of the flexible flat cable 1. .
Then, as shown in FIG. 6, the intermediate product of the shield flat cable 1 thus produced is sandwiched between the pressing members 20 and subjected to heat and pressure treatment, whereby the insulating resin layer 103, the shield layer 105, and The low dielectric layer 104 is bonded together.

Here, when the low dielectric layer 104 and the shield layer 105 are integrally bonded to the insulating resin layer 103, a pressing member 20 in which a rubber plate 22 is laminated on a base 21 made of an aluminum plate is used. However, in order to adhere the shield layer 105 by pressing, it is necessary to perform pressing at a temperature of approximately 95 ° C. or higher. When pressing is performed at this temperature, bubbles a having a diameter of 4 mm or more as shown in FIG. 7 may be generated between the low dielectric layer 104 and the insulating resin layer 103.
If this bubble a is large, the impedance of the flat cable at that location is partially changed (spikes are generated), which may cause the flat cable to be defective depending on the degree, and is not preferable in appearance. .

  The present invention has been made in view of the above situation, and manufactured a shielded flat cable in which a low dielectric layer is provided between an insulating layer covering both surfaces of a plurality of conductors and an outermost shield layer. It is an object of the present invention to provide a method for manufacturing a shielded flat cable that can disperse bubbles generated between an insulating layer and a low dielectric layer in a small amount, and a pressing member used for manufacturing the shielded flat cable.

In order to solve the above-mentioned problem, a method for manufacturing a shielded flat cable according to the present invention includes a conductor row in which a plurality of conductors are arranged in parallel, and an insulating resin layer sandwiched between both sides of the arrangement surface of the conductor row. An intermediate product of a shielded flat cable is manufactured, and a low dielectric layer and a shield layer are sequentially laminated on each of the insulating resin layers on both sides of the intermediate product, and both sides of the shield layer are sandwiched between pressing members. By applying heat and pressure, the low dielectric layer and the shield layer are bonded together. At that time, as the pressing member, a rubber plate having a low hardness is provided on the base, a rubber plate having a high hardness is provided thereon, and a release tape having an uneven surface is provided thereon. ing.

  According to the present invention, bubbles generated between the insulating resin layer and the low dielectric layer of the shielded flat cable can be dispersed small, and the appearance can be improved.

It is the schematic which shows the structure of the shield flat cable used as the object of the manufacturing method of this invention. It is a figure which shows one Embodiment which concerns on the manufacturing method of the shield flat cable of this invention. It is a figure for demonstrating the pressing member which concerns on this invention. It is a figure which shows the bubble which generate | occur | produced in the shield flat cable by experiment. It is the figure which simplified and showed the cross section of the flat cable which has a low dielectric layer. It is a figure for demonstrating the conventional pressing member. It is a figure which shows that a big bubble generate | occur | produced between the low dielectric layer and the insulating layer by the conventional manufacturing method.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of a method for producing a shielded flat cable according to the invention and a pressing member used for production will be described with reference to the drawings.
FIG. 1 is a schematic diagram showing the configuration of a shielded flat cable that is a target of the manufacturing method of the present invention, FIG. 1 (A) is a top view, and FIG. 1 (B) is A in FIG. 1 (A). It is -A sectional drawing. Moreover, FIG. 2 is a figure which shows one Embodiment which concerns on the manufacturing method of the shield flat cable of this invention.

  As shown in FIG. 1, a shielded flat cable 1 subject to the manufacturing method of the present invention has a structure in which both sides of a conductor array in which a plurality of flat conductors 2 are arranged in parallel are covered with an insulating resin layer 3. Have The insulating resin layer 3 includes a resin layer 5 and an adhesive layer 4 laminated on the resin layer 5, and a plurality of conductors 2 are sandwiched between the two insulating resin layers 3. The two insulating resin layers 3 are bonded together.

  A low dielectric layer 6 for adjusting the characteristic impedance of the flexible flat cable 1 is provided outside the insulating resin layer 3. In the shielded flat cable 1 of the present embodiment, the low dielectric layer 6 is provided on the outer surfaces of the pair of resin layers 5 via the adhesive layer 7 laminated on the low dielectric layer 6.

  Furthermore, the shield flat cable 1 of the present embodiment is configured to provide a shield layer 9 for reducing electromagnetic interference and noise on the outer surfaces of the pair of low dielectric layers 6. For producing the shield layer 9, for example, a conductive metal such as silver is vapor-deposited on the inner surface of an insulating resin film such as a polyethylene terephthalate resin having a thickness of 9 μm. A shield tape coated with a conductive adhesive layer such as silver paste can be used. The shield tape is not limited to such a structure, and may be provided with only a conductive adhesive layer.

Further, an easy adhesion layer 8 is provided between the low dielectric layer 6 and the shield layer 9, and the low dielectric layer 6 and the shield layer 9 are bonded via the easy adhesion layer 8. ing.
In addition, in order to connect the conductor 2 with the connection terminal which is not shown in figure provided in the printed circuit board, the electrical / electronic component, etc. in the edge part of the shield flat cable 1, without forming the insulating resin layer 3, it is a part of conductor 2 Is exposed to the outside.

  In manufacturing the shield flat cable 1, first, as shown in FIG. 2A, a plurality of conductors 2 are arranged in parallel. The conductor 2 is made of a conductive metal foil such as copper foil or tin-plated annealed copper foil, and corresponds to the amount of current to be used. In consideration of slidability and the like, a conductor having a thickness of 20 μm to 50 μm is preferably used. And as shown in FIG.2 (B), both surfaces of the arrangement surface of the conductor 2 are inserted | pinched with the insulating resin layer 3 which laminated | stacked the adhesive bond layer 4 on the resin layer 5, and a known thermal laminator and a hot press apparatus were used. Thus, an intermediate product in which both surfaces of the conductor 2 are covered with the insulating resin layer 3 is manufactured.

Here, the resin layer 5 is made of a resin material having excellent flexibility. For example, a resin film having a versatility for a flexible flat cable made of a polyester resin, a polyphenylene sulfide resin, a polyimide resin, or the like is used. Any of them can be used, and those having a thickness of 12 μm to 50 μm can be suitably used.
The adhesive layer 4 is made of a resin material. For example, an adhesive obtained by mixing a flame retardant with a polyester resin can be used. The adhesive layer 4 preferably has a thickness of 20 μm to 50 μm.

  Next, a pair of tapes in which the adhesive layer 7 is provided on the inner surface of the low dielectric layer 6 and the easy-adhesion layer 8 is provided on the outer surface are formed in advance. As shown in FIG. A low dielectric layer 6 is disposed on the outer surface of the resin layer 5. The easy adhesion layer 8 is for reliably bonding the low dielectric layer 6 and a shield layer 9 described later.

  As the low dielectric layer 6, a material having a low dielectric property and a hard resin composition having a low environmental load is used as a main component, and as this resin material, polyethylene (PE), polycarbonate resin (PC ), Modified polyphenylene ether resin (PPE), polyphenylene sulfide resin (PPS), polyimide resin (PI), polyetherimide resin (PEI), polyarylate resin (PAR), fluorine resin, styrene thermoplastic elastomer, and olefin A thermoplastic elastomer can be used. Moreover, in order to set the value of the characteristic impedance of the shield flat cable 1 to a desired value, the thickness is set to 100 μm to 350 μm, for example.

  Examples of the resin constituting the adhesive layer 7 include vinyl acetate resin (EVA and the like), acrylic resin, natural rubber, polyisoprene rubber, nitrile rubber, styrene / butane diene rubber, butyl rubber, polymethacrylate resin, polyvinyl Butyrate, epoxy resin, silicone resin and the like can be used. The thickness of the pressure-sensitive adhesive layer 8 can suitably be 5 to 60 μm.

  As the resin constituting the easy-adhesion layer 8, for example, urethane resin, vinyl acetate resin, acrylic resin, ethylene-vinyl acetate copolymer, polymethyl methacrylate resin, rubber resin and the like can be used. In addition, these resin may be used independently and may mix and use 2 or more types. The easy-adhesion layer 10 having a thickness of 0.1 μm to 5 μm can be suitably used.

  Next, as shown in FIG. 2 (D), a shield tape prepared in advance is applied to the easy-adhesion layer 10 of the low dielectric layer 6 located on both outer surfaces of the shield flat cable 1 and the thickness of the shield flat cable 1. The shield layer 9 is provided on the outer surface of the low dielectric layer 6 so as to cover both end faces in the vertical direction.

  Next, the insulating resin layer 3, the low dielectric layer 6, and the shield layer 9 are heated and pressed by a hot press apparatus with both surfaces of the shield layer 9 of the laminate in the state shown in FIG. Are bonded together to obtain a shielded flat cable 1.

FIG. 3 is a view for explaining a pressing member according to the present invention. In the pressing member 10, a lower rubber plate 12 having a low hardness is provided on a base 11 made of an aluminum plate, and the hardness of the lower rubber plate 12 is set on the lower rubber plate 12. A high upper rubber plate 13 is provided, and a release tape 14 is further provided thereon.
Further, the Shore A hardness of the upper rubber plate 13 having high hardness is 60 to 80, and the hardness of the lower rubber plate 12 having low hardness is 10 or more in Shore A hardness compared to the hardness of the upper rubber plate 13 having high hardness. By having a difference, bubbles generated between the insulating resin layer 3 and the low dielectric layer 6 can be dispersed small.

Below, this invention is demonstrated based on an Example and a comparative example.
Table 1 compares the size of bubbles generated between the insulating resin layer 3 and the low dielectric layer 6 by changing the hardness of the lower rubber plate 12 with respect to the upper rubber plate 13.
As the pressing member 10, a rubber plate having a thickness of 2.3 mm and a Shore A hardness of 50, 60 or 70 is provided as a lower rubber plate 12 on a base 11 of an aluminum plate, and a thickness of 3.0 mm is provided thereon. Three holding members 10 each having a rubber plate 13 having a Shore A hardness of 70 were prepared.

As the release tape 14 for the uppermost layer, glass cloth is effective, glass fiber is woven into a Teflon (registered trademark) tape, and the thickness is 0.13 mm, and the thickness is 0.3 mm. What used the grid | lattice form at the space | interval was used.
The size of the pressing member 10 is a length and width that can cover the shield flat cable 1, and the pressing conditions include a pressing surface temperature of 100 ° C., a pressing pressure of 0.65 MPa, and a pressing time of 5 s. did.

If it is determined that a bubble having a size of 4.0 mm or more is generated, the lower rubber plate 12 has a Shore A hardness of 50 or 60, that is, the lower rubber plate 12 has a Shore A hardness of the upper rubber layer. In the case where the hardness difference was 10 or more than the Shore A hardness of the plate 13, as shown in FIG.
However, when the Shore A hardness of the lower rubber plate 12 is the same Shore A hardness 70 as that of the upper rubber plate 13, as shown in FIG. .

From the experimental results, the release tape 14 disperses the air bubbles by the mesh (surface irregularities) of the glass cloth and prevents the rubber plate from being worn. However, when the hardness of the rubber plate was 70 both above and below, the bubbles could not be dispersed small, and by overlapping two rubber plates with different hardness, the bubbles could be dispersed small.
This is because at the moment of pressing, it is thought that the air that was between each layer was made fine by the glass cloth and escaped in a wide range to eliminate large bubbles by the action of the rubber with low hardness, and then the rubber with high hardness disappeared. It is considered that the low dielectric layer and the shield layer are sufficiently bonded by the above action.

  By performing the same experiment, the Shore A hardness of the upper rubber plate 13 is 60 to 80, the Shore A hardness of the lower rubber plate 12 is 40 to 60, and the Shore A hardness of the lower rubber plate 12 and the upper rubber plate is It is considered that when the hardness difference is 10 or more, the generated bubbles are dispersed small.

DESCRIPTION OF SYMBOLS 1 ... Shield flat cable, 2 ... Conductor, 3 ... Insulating resin layer, 4 ... Adhesive layer, 5 ... Resin layer, 6 ... Low dielectric layer, 7 ... Adhesive layer, 8 ... Easy-adhesion layer, 9 ... Shield layer, DESCRIPTION OF SYMBOLS 10 ... Holding member, 11 ... Base (aluminum plate), 12 ... Lower layer rubber plate, 13 ... Upper layer rubber plate, 14 ... Release tape, 20 ... Holding member, 21 ... Base (aluminum plate), 22 ... Rubber plate , 101 ... shield flat cable, 102 ... conductor, 103 ... insulating resin layer, 104 ... low dielectric layer, 105 ... shield layer.

Claims (3)

An intermediate product of a shielded flat cable in which a conductor row in which a plurality of conductors are arranged in parallel and the insulating resin layer is sandwiched between both sides of the arrangement surface of the conductor row is manufactured, and the insulating resin on both sides of the intermediate product A low dielectric layer and a shield layer are sequentially laminated on each of the layers, and the low dielectric layer and the shield layer are bonded together by heating and pressing with both sides of the shield layer sandwiched between pressing members. A method of manufacturing a shielded flat cable,
The pressing member is provided with a low hardness rubber plate on the base, a high hardness rubber plate on the low hardness rubber plate, and a surface with irregularities on the high hardness rubber plate. A method for producing a shielded flat cable, characterized in that a release tape is provided.   The method for producing a shielded flat cable according to claim 1, wherein the rubber plate having high hardness and the rubber plate having low hardness have a hardness difference of 10 or more in Shore A hardness. The method for producing a shielded flat cable according to claim 1 or 2, wherein the rubber plate having a high hardness is a rubber plate having a Shore A hardness of 60 to 80.

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