JP2019067520A - Flat cable - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a low-cost flat cable capable of eliminating a potential difference between a plurality of electric wires arranged in parallel, aligning the potentials, maintaining electrical characteristics, and significantly reducing processing man-hours. SOLUTION: A plurality of electric wires 10 having a central conductor 1 and a dielectric layer 2 provided on the outer periphery of the central conductor 1 are arranged in parallel at regular intervals, and the plurality of electric wires 10 are fixed from both sides. The flat cable 10 integrated with the tape 11 is configured such that the fixing tape 11 is a tape having a conductive adhesive layer 11B or a conductive layer 11C and an adhesive layer 11D, and solves the above-mentioned problems. Solve. When the fixing tape 11 has the conductive layer 11C and the adhesive layer 11D, it is preferable that the conductive layer 11C and the adhesive layer 11D are laminated. [Selection diagram] FIG. 4

Description

  The present invention relates to a flat cable, and more particularly, to a low cost flat cable which is used in or between electronic devices such as a liquid crystal television and a server and is suitable for propagation of high frequency signals and which is easy to process.

  Flat cables are excellent in processability and flexibility, and are widely used as internal wiring materials and external wiring materials of electronic devices. In particular, a flat cable using a plurality of coaxial cables has been proposed as a flat cable suitable for propagation of high frequency signals. For example, Patent Document 1 proposes a coaxial flat cable in which a plurality of coaxial cables having an outer diameter of 0.15 to 0.35 mm are arranged in parallel and fixed to a laminate sheet.

  In such a coaxial flat cable, as described in, for example, Patent Document 2, each of the outer conductors of the coaxial cables arranged in parallel is soldered by soldering over the arrangement direction of the coaxial cables. It is described in the same document that such a soldering makes it possible to equalize the potentials of the outer conductors of all coaxial cables and to easily maintain the electrical characteristics. However, in this soldering operation, the outer conductor (insulation layer) of each coaxial cable is peeled off to expose the outer conductor, and then the soldering is performed. The cable may be crushed, which may deteriorate the transmission characteristics.

  On the other hand, Patent Document 3 proposes a shielded electrical cable. This shielded electric cable is a flat cable in which a plurality of electric wires are arranged in parallel and fixed to a shielding film, and the outer conductor as disclosed in Patent Document 2 is peeled off and soldered.

JP, 2006-222059, A JP, 2015-133187, A JP, 2013-219054, A

  In Patent Document 3 described above, the shielding film includes a cover portion in which the electric wire is present and a pinched portion in which the shielding films in the absence of the electric wire are in direct contact with each other. Are configured to substantially surround each conductor set together. Also, although the adhesive layer is provided to put together the shielding film at the pinched portion of the cable, the pinched portion is present at the middle portion of the flat cable, so the width of the flat cable is wide. The problem is that the distance between the wires can not be constant.

  In addition, the fact that the potentials between the electrodes are uniform is required as a wire for high frequency signals used in electronic devices or between electronic devices, and flat cables with a low-cost structural form that can reduce the number of processing steps. It is required.

  The present invention has been made to solve the above-mentioned problems, and its object is to eliminate the potential difference between a plurality of wires arranged in parallel and to maintain the electrical characteristics by aligning the potentials. It is an object of the present invention to provide a low cost flat cable which can be further reduced in the number of processing steps.

  In the flat cable according to the present invention, a plurality of electric wires having a central conductor and a dielectric layer provided on the outer periphery of the central conductor are arranged in parallel at regular intervals, and the plurality of electric wires are fixed from both sides It is characterized in that the fixing tape is a tape having a conductive adhesive layer, or a conductive layer and an adhesive layer.

  According to the present invention, since the fixing tape is provided with the layer having conductivity (conductive adhesive layer or conductive layer), the fixing tape is fixed by fixing a plurality of electric wires from both sides with the fixing tape. Acts as a tape-like outer conductor, and can eliminate the potential difference between the wires to equalize the potential. As a result, electrical characteristics can be maintained. Furthermore, since each electric wire does not have an outer conductor such as a coaxial cable or an insulating layer, it is possible to provide a low cost flat cable which can reduce the number of processing steps.

  In the flat cable according to the present invention, when the fixing tape has the conductive layer and the adhesive layer, it is preferable that the conductive layer and the adhesive layer be laminated.

  According to the present invention, since the conductive layer is provided on the adhesive layer adhered to the outer conductor of the wire, the potential can be further stabilized.

  In the flat cable according to the present invention, both surfaces of the plurality of electric wires are sandwiched by two sheets of the fixing tape or covered with one sheet of the fixing tape.

  According to the present invention, since both surfaces of a plurality of electric wires arranged in parallel are covered with one or two fixing tapes having a conductive layer (conductive adhesive layer or conductive layer) The potential can be uniformed without potential difference, and the electrical characteristics can be maintained.

  In the flat cable according to the present invention, it is preferable that the dielectric layer has a gap that is continuous in the longitudinal direction.

  According to the present invention, since the dielectric layer has the continuous void in the longitudinal direction, the dielectric constant can be reduced by the presence of the void. As a result, the outer diameter of the central conductor can be increased without increasing the outer diameter of the wire, and the effective cross-sectional area of the central conductor can be increased to suppress an increase in high frequency resistance (AC resistance). Furthermore, the dielectric layer having a void portion continuous in the longitudinal direction is more likely to be produced at the time of manufacturing (for example, when applying pressure such as heat sealing) or at the time of wiring operation as compared with a dielectric layer consisting of a foam layer Since it is hard to collapse and the distance between the central conductor and the outer conductor does not change, the characteristic impedance can be stabilized and the high frequency characteristics can be stabilized.

  In the flat cable according to the present invention, the dielectric layer is a hollow structure including an inner annular portion, an outer annular portion, and a connection portion connecting the two, and the hollow structure is formed of a fluorocarbon resin. Is preferred.

  According to the present invention, since the hollow structure is excellent in the side pressure strength, it is difficult to be crushed at the time of manufacturing, at the time of wiring operation and the like, and high frequency characteristics can be stabilized. Further, for example, a fluorine-based resin such as PFA (ε2.1) has a dielectric constant smaller than that of polyethylene (ε 2.2 to 2.6) and the like, so that high frequency transmission characteristics can be further improved. The dielectric constant can be reduced according to the porosity of

  According to the present invention, it is possible to eliminate the potential difference between a plurality of wires arranged in parallel, equalize the potential and maintain the electrical characteristics, and provide a low-cost flat cable which can significantly reduce the number of processing steps. can do. In particular, it is possible to provide a low-cost flat cable which is used in an electronic device such as a liquid crystal television or a server or between electronic devices and which is suitable for propagation of high frequency signals and which is easy to process. Since this flat cable has a structure in which the electric wires do not have an outer conductor individually, it is excellent in manufacture and processability, and can be reduced in cost. Moreover, the deterioration of the transmission characteristic due to the variation of the processing state can be prevented.

It is a sectional view showing an example of a flat cable concerning the present invention. It is sectional drawing which shows an example of an electric wire. It is a general view of the flat cable which unified both sides of the electric wire with fixed tape. The flat cable which concerns on this invention WHEREIN: It is explanatory drawing which shows three forms of fixing tape. It is sectional drawing which shows the example of the conventional electric wire which has an outer conductor and an insulating layer.

  An embodiment of a flat cable according to the present invention will be described with reference to the drawings. The present invention includes inventions of the same technical concept as the embodiments described below and the embodiments described in the drawings, and the technical scope of the present invention is limited only to the description of the embodiments and the drawings. It is not a thing.

  In the flat cable 20 according to the present invention, as shown in FIGS. 1 to 4, a plurality of electric wires 10 having the central conductor 1 and the dielectric layer provided on the outer periphery of the central conductor 1 are paralleled at a constant interval. Were distributed to Then, the plurality of electric wires 10 are integrated with the fixing tape 11 from both sides. Then, the fixing tape 11 is a tape having the conductive adhesive layer 11B or the conductive layer 11C and the adhesive layer 11D.

  In the flat cable 20, the fixing tape 11 is provided with a conductive layer (conductive adhesive layer 11B or conductive layer 11C), so the fixing tape 11 fixes the plurality of electric wires 10 from both sides. Thereby, the fixing tape 11 acts as a tape-like outer conductor, and the potential difference between the respective wires can be eliminated to make the potential uniform. As a result, electrical characteristics can be maintained. Furthermore, since each electric wire 10 has neither the outer conductor 103 such as the coaxial cable 100 (see FIG. 5) nor the insulating layer 104, it is possible to provide a low-cost flat cable that can reduce the number of processing steps.

  Hereinafter, each component of the flat cable will be described.

(Central conductor)
As shown in FIGS. 1 to 3, the central conductor 1 is configured by one strand extending in the longitudinal direction Y of the electric wire 10 or is configured by twisting a plurality of strands. . The type of wire is not particularly limited as long as the wire is a good conductive metal, but a metal wire with good conductivity such as copper wire, copper alloy wire, aluminum wire, aluminum alloy wire, copper aluminum composite wire, or the like Preferred are those having a plating layer applied thereto. From the viewpoint of high frequency, copper wire and copper alloy wire are particularly preferable. As a plating layer, a solder plating layer, a tin plating layer, a gold plating layer, a silver plating layer, a nickel plating layer etc. are preferable. The cross-sectional shape of the strands is also not particularly limited, but the cross-sectional shape may be circular, substantially circular or square.

  The cross-sectional shape of the central conductor 1 is also not particularly limited, but may be circular (including oval) or rectangular (including square, pentagon, hexagon, octagon, etc.). The outer diameter of the central conductor 1 is desirably as large as possible so as to reduce the electrical resistance (AC resistance, conductor resistance), and may be, for example, about 0.1 to 0.4 mm. Specifically, it may be about AWG 28 to 36 (7 / 0.127 to 7 / 0.05), preferably AWG327 / 0.08 (outside diameter: about 0.24 mm) or the like. An insulating film (not shown) may be provided on the surface of the central conductor 1 as necessary. Although the type and thickness of the insulating film are not particularly limited, those which can be favorably decomposed at the time of soldering are preferable, and for example, a thermosetting polyurethane film can be preferably used. AWG (abbreviation of American Wire Gauge) is a symbol known as a dimensional standard of a conductor, and is also called B & S (Brown and Sharp) Gauge.

(Dielectric layer)
The dielectric layer 2 is a low dielectric constant insulating layer provided on the outer periphery of the central conductor 1 as shown in FIGS. 1, 2 and 4. The configuration of the dielectric layer 2 is not particularly limited. However, as shown in FIG. 2, it is preferable to have a void 2A continuous in the longitudinal direction Y. The air gap 2A is continuously provided in the dielectric layer 2, but the form thereof may be round or rectangular, and is not particularly limited. In particular, in the hollow structure 2 (which may have the same reference numeral 2 as the dielectric layer) formed of the inner annular portion 2B, the outer annular portion 2C, and the connecting portion 2D that connects these, the void portion 2A is an inner ring. It is a cross-sectional form surrounded by the portion 2B, the outer annular portion 2C and the connecting portion 2D, and is preferable because it is excellent in the side pressure strength. The hollow structure 2 excellent in side pressure strength is unlikely to be crushed at the time of manufacture of the electric wire 10 and the flat cable 20, at the time of wiring operation of the flat cable 20, etc., and high frequency characteristics can be stabilized. The hollow structure 2 can be formed by, for example, extruding a PFA resin on the outer periphery of the central conductor 1 traveling on the extrusion die. PFA is a copolymer of tetrafluoroethylene and perfluoroether. The thickness of each of the inner annular portion 2B, the outer annular portion 2C and the connecting portion 2D is not particularly limited, but is, for example, in the range of about 0.01 to 0.05 mm, and the formed hollow structure 2 (dielectric layer The outer diameter of 2) is, for example, in the range of about 0.4 to 1.0 mm.

  The dielectric layer 2 is preferably made of, for example, a fluorine-based resin such as PFA (dielectric constant ε: 2.1). The fluorine-based resin has a dielectric constant smaller than that of a polyolefin resin such as polyethylene (dielectric constant ε: 2.2 to 2.6), so that high frequency transmission characteristics can be further improved. Furthermore, the dielectric constant can be reduced according to the void ratio of the above-described hollow structure 2. As an example, the outer diameter of the hollow structure 2 is, for example, 0.58 mm, and the ratio of the void 2A (void ratio) ) Can be reduced to about 1.5 to 1.65. The void ratio of the void portion 2A is preferably in the range of 20% to 60% with respect to the area of the entire dielectric layer (entire hollow structure).

  In such a dielectric layer 2, it is preferable to adopt a hollow structure that preferably has a void 2A capable of achieving a low dielectric constant and can increase the side pressure strength, and more preferably withstands heating pressure such as heat sealing. To be selected. Since the dielectric layer 2 having such a structure can lower the dielectric constant, the outer diameter of the central conductor 1 can be increased without increasing the outer diameter of the wire 10, and the effective cross-sectional area of the central conductor 1 can be increased. An increase in high frequency resistance (AC resistance) can be suppressed. Furthermore, the dielectric layer 2 having the void portion 2A continuous in the longitudinal direction is compared to the dielectric layer formed of the foam layer not continuous in the longitudinal direction at the time of manufacturing (for example, at the time of pressurization of heat sealing etc.) The characteristic impedance is stable and the high frequency characteristics are stable because the distance between the central conductor 1 and the conductive layer (conductive adhesive layer 11B or conductive layer 11C) of the fixing tape 11 described later does not change. It can be

  The outer conductor 103 and the insulating layer 104 as shown in FIG. 5 do not exist on the outer periphery of the dielectric layer 2.

(Flat cable)
The flat cable 20, as shown in FIGS. 1 to 4, as described above, a plurality of electric wires 10 arranged in parallel at a constant interval P, and a fixing tape 11 for integrating the electric wires 10 from both sides. Are configured to have The constant spacing P is equal pitch spacing within the range of 0.4 to 1.0 mm, and by setting equal pitch spacing, it is effective in terms of connection to the connector. Furthermore, in the present invention, the outer conductor 103 and the insulating layer 104 provided on the outer periphery of the dielectric layer 2 do not exist (see FIG. 5). Therefore, even if the central conductor 1 is thickened, it is possible to limit the thickening of the outer diameter of the individual electric wires 10 in which they do not exist. As a result, the flat cable 20 exhibiting stable and excellent high frequency characteristics can be used without changing the existing connector, without exceeding the desired connector pitch. The wire 10 is as described above.

(Fixed tape)
The fixing tape 11, as shown in FIG. 1, FIG. 3 and FIG. 4, integrates the entire surface excluding the end portions 21 (connection processing portions with other parts such as connectors) of the plurality of wires 10 from both sides. is there. In the present invention, since the electric potential of the electric wire 10 is aligned without any potential difference to maintain the electric characteristics, it is preferable to provide the fixing tape 11 not on one side but on both sides as shown in FIGS. As an embodiment in which the fixing tape 11 is provided on both sides, it is preferable to sandwich and bond them by two fixing tapes 11 and integrate them, or cover and bond and integrate them so as to wrap both sides with one fixing tape 11. .

  FIG. 3 shows an embodiment in which both surfaces of a plurality of electric wires 10 are sandwiched between two fixing tapes 11 and integrated. The fixing tape 11 is bonded to all of the longitudinal direction Y of the plurality of electric wires 10. In the example of FIG. 3, two fixing tapes 11 sandwich and bond from both sides and are integrated, but one fixing tape 11 may be folded back and may be bonded and integrated from both sides. .

  As the fixing tape 11, as shown to FIG. 4 (A) (B) (C), three forms can be mentioned preferably. As shown in FIG. 4A, the first fixing tape 11a has a base 11A and a conductive adhesive layer 11B provided on one side of the base 11A. As shown in FIG. 4B, the second fixing tape 11b is obtained by laminating the base material 11A, the conductive layer 11C, and the adhesive layer 11D in that order. As shown in FIG. 4C, the third fixing tape 11c is obtained by laminating the conductive layer 11C, the base material 11A, and the adhesive layer 11D in that order. These first to third fixing tapes 11 (11a, 11b, 11c) have a conductive adhesive layer 11B, or a conductive layer 11C and an adhesive layer 11D, and a layer having adhesiveness (conductive adhesive It is bonded to the dielectric layer 2 via the layer 11B and the adhesive layer 11D. Therefore, the potentials of all the wires 10 can be made uniform without any potential difference, and the electrical characteristics can be maintained. When the conductive layer 11C and the adhesive layer 11D are provided as in the second fixing tape 11b, it is preferable that the conductive layer 11C and the adhesive layer 11D be stacked, and the potential be further stabilized. it can. Further, in the second fixing tape 11b and the third fixing tape 11c, the layer denoted by reference numeral 11D may be a conductive adhesive layer, and in such a case, it functions to further stabilize the potential together with the conductive layer 11C. Do.

  The substrate 11A is not particularly limited, but polyester films such as polyethylene terephthalate and polyethylene naphthalate can be preferably used. From the viewpoint of peelability, a uniaxially stretched film is preferred. The thickness of the base material 11A is optionally selected in the range of about 25 to 100 μm.

  The conductive adhesive layer 11B constituting the first fixing tape 11a is an adhesive layer having conductivity, and examples thereof include an adhesive layer containing a conductive material (conductive powder or conductive filler). Examples of the material of the conductive material include copper, silver, nickel, carbon and the like having good conductivity. The conductive adhesive layer 11B can preferably include a thermoplastic adhesive resin containing a conductive material, for example, a hot melt adhesive containing a conductive material. In the first fixing tape 11a, the conductive adhesive layer 11B is provided on the base 11A. The thickness of the conductive adhesive layer 11B is arbitrarily selected in the range of about 20 to 100 μm. The entire thickness of the first fixing tape 11a is arbitrarily selected in the range of about 50 to 150 μm.

  The conductive layer 11C constituting the second fixing tape 11b is not particularly limited as long as it is a layer having conductivity, and may be a metal layer or a conductive paste layer containing conductive powder. In particular, a metal layer is preferable, and a copper layer, an aluminum layer or the like formed by vapor deposition or plating on the base material 11A, or a film obtained by bonding them can be mentioned preferably. The thickness of the conductive layer 11C is different depending on the forming means, but the one formed by vapor deposition or plating is arbitrarily selected from the range of about 2 to 7 μm, and the one obtained by bonding metal layers is within the range of about 10 to 100 μm It is arbitrarily selected from

  Preferred examples of the adhesive layer 11D constituting the second fixing tape 11b include polyester-based thermoplastic adhesive resin layers and the like. The thickness of the adhesive layer 11D is optionally selected in the range of about 25 to 50 μm. The entire thickness of the fixing tape 11 b is arbitrarily selected in the range of about 37 to 200 μm. As described above, the layer denoted by reference numeral 11D may be a conductive adhesive layer, and in such a case, it acts to further stabilize the potential together with the conductive layer 11C.

  The third fixing tape 11c is the same as the second fixing tape 11b, although the stacking order of the individual layers is different, and therefore the description thereof is omitted here.

  In addition, by using a sufficiently thick tape having a total thickness of, for example, about 0.1 to 0.2 mm, the fixing tape 11 can be made less susceptible to heat during heat bonding in a heat sealing process or the like, As a result, contraction hardly occurs, and a stable pitch of the electric wire 10 can be secured.

  Hereinafter, the present invention will be more specifically described by way of examples. The present invention is not limited to the following examples.

Example 1
The flat cable 20 illustrated in FIG. 4 (B) was produced. As the central conductor 1, an AWG 32 (having an outer diameter of about 0.24 mm) in which seven silver-plated soft copper wires having a diameter of 0.08 mm are twisted is used. The dielectric layer 2 is formed by extruding a PFA resin (made by DuPont) at 350 ° C. with a die nipple for a hollow structure, and the void 2A is surrounded by the inner annular portion 2B, the outer annular portion 2C and the connecting portion 2D. A hollow structure in cross-sectional form was formed. In this hollow structure, the thickness of the inner annular portion 2B is 0.05 mm, the thickness of the outer annular portion 2C is 0.05 mm, and the thickness of the connecting portion 2D is 0.05 mm. The outer diameter of 2) was 0.60 mm, and the void ratio of the voids 2A was 30% with respect to the area of the entire dielectric layer (entire hollow structure). In addition, the shape of the space | gap part 2A was substantially trapezoid shape, as shown to FIG. 4 (B). The dielectric constant ε was about 1.6.

  Sixteen obtained electric wires 10 were prepared, arranged in parallel at a constant interval P of 1 mm, and then bonded and integrated from both sides with a second fixing tape 11 b. The second fixing tape 11b is a polyethylene terephthalate film with aluminum layer (thick) in which a polyester thermoplastic resin (adhesive layer 11D) with a thickness of 0.035 mm is provided on an aluminum layer (conductive layer 11C) with a thickness of 0.05 mm. 0.1 mm) was cut into a width of 25 mm.

Example 2
The flat cable illustrated in FIG. 4A was produced in the same manner as in Example 1 except that the first fixing tape 11a was used. The first fixing tape 11a includes a base 11A (PET film, about 0.012 mm in thickness) manufactured by Hyen Electric Co., Ltd., and a conductive adhesive layer 11B (polyester thermoplastic resin and a conductive material). What consisted of 013 mm was used by cutting to a width of 25 mm. The dielectric constant ε was about 1.6.

Comparative Example 1
As the fixing tape, a polyethylene terephthalate film (whole thickness: 0.060 mm) provided with a polyester thermoplastic resin (adhesive layer 11D) with a thickness of 0.035 mm was cut into a width of 25 mm. A flat cable was produced in the same manner as in Example 1 except for the above. The dielectric constant ε was about 1.6.

Comparative Example 2
A flat cable was produced in the same manner as in Example 1 except that the coaxial cable 100 having the outer conductor 103 and the insulating layer 104 was used. The outer conductor 103 was formed of 38 silver-plated soft copper wires having a diameter of 0.05 mm, and wound around the outer periphery of the dielectric layer 2 at a pitch of 12 mm using a horizontal winding shield machine to form fine horizontal winding. Furthermore, a 0.004 mm thick polyethylene terephthalate film (insulation tape with a metal layer) on which a 0.008 mm thick copper layer is formed is cut into a width of 2.5 mm, and the copper layer is fine-lined using a tape winding machine. It turned to the winding side and wound it with 1 / 3.5 lap. The insulating layer 104 is formed by cutting a 0.004 mm thick polyester tape provided with a 0.001 mm thick polyester thermoplastic resin (adhesive layer) on one side and bonding it using a tape winding machine. The agent layer is on the outer conductor side and wound with 1/3 wrap. The dielectric constant ε was about 1.6.

Comparative Example 3
A flat cable was produced in the same manner as in Example 1 except that the dielectric layer 2 was a foam layer having a minute air layer. The foamed layer was formed by extrusion molding of a foaming agent-containing polyethylene compound, the porosity of the foamed layer was about 30%, and the dielectric constant ε was about 1.8.

[Measurement and result]
(Electrical characteristics)
At the time of processing work, heating (about 170 ° C.) and pressure (about 0.2 MPa) are applied when heat sealing a plurality of electric wires 10 with fixing tape 11. It was investigated whether or not the propagation delay time was changed by deforming.

  The propagation delay time of the coaxial flat cable is evaluated by using the coaxial flat cable cut into a fixed length (for example, 1 m) as a sample, and measuring the impedance and propagation delay time of the sample connected to the measuring machine by TDR method did. The presence or absence of deformation such as crushing was estimated from the variation (SKEW) of the obtained propagation delay time. As a measuring instrument, a Tektronix DCA 8200 sampling oscilloscope (TDR module: 80E04) was used.

  As shown in the results of Table 1, in Example 1, since GND is common over the entire length with respect to Comparative Example 2, in-pair SKEW is hard to occur, the outer diameter is reduced, and the finished thickness is reduced. The By setting the common GND, it is possible to improve the transmission characteristics by reducing the SKEW within and between the pairs. In the second embodiment, the effect of the common GND is smaller than that of the first embodiment, and the decrease in in-pair SKEW is slight. On the other hand, in Comparative Example 1, the differential signal could not be transmitted because the shield was not present, and the measurement could not be performed. In Comparative Example 2, since the pair internal signal is independent, the delay speed of the coaxial line is measured as it is, and common GND processing (insulation peeling and GND connection processing) at the terminal is required, and the outer diameter is large and the pitch is There is a problem that the thickness is increased and the thickness of the finish is also increased. In Comparative Example 3, the foam was crushed during lamination, the variation in the electrostatic capacitance (dielectric constant) of the insulator was large, and the SKEW was also large.

  From the above results, the flat cable 20 can maintain the electrical characteristics by eliminating the potential difference between the plurality of electric wires arranged in parallel (1) and maintaining the electric characteristics, and in particular, the liquid crystal television, server, etc. It is promising as a flat cable which is used in electronic devices or between electronic devices, is suitable for propagation of high frequency signals, is easy to process, and is inexpensive. (2) Since neither the outer conductor nor the insulating layer is provided, it has been possible to provide a low-cost flat cable which can significantly reduce the number of processing steps. In addition, (3) the wires 10 do not have an outer conductor individually, so that the manufacturing and processability are excellent and the cost can be reduced. Moreover, the deterioration of the transmission characteristic due to the variation of the processing state can be prevented.

1 central conductor 2 dielectric layer (hollow structure)
2A void 2B inner annular portion 2C outer annular portion 2D connecting portion 10 electric wire 11 fixing tape 11a first fixing tape 11b second fixing tape 11c third fixing tape 11A base 11B conductive adhesive layer 11C conductive layer 11D adhesive layer 20 flat cable 21 terminal 22 middle part (part other than the terminal)
100 electric wire 103 outer conductor 104 insulating layer P pitch (distance)
Y longitudinal direction

Claims (5)

  A flat cable in which a plurality of electric wires having a central conductor and a dielectric layer provided on the outer periphery of the central conductor are arranged in parallel at regular intervals, and the plurality of electric wires are integrated with fixing tape from both sides. A flat cable characterized in that the fixing tape is a tape having a conductive adhesive layer or a conductive layer and an adhesive layer.   The flat cable according to claim 1, wherein when the fixing tape has the conductive layer and the adhesive layer, the conductive layer and the adhesive layer are laminated.   The flat cable according to claim 1, wherein both surfaces of the plurality of electric wires are sandwiched by two sheets of the fixing tape or covered by one sheet of the fixing tape.   The flat cable according to any one of claims 1 to 3, wherein the dielectric layer has a longitudinally continuous void. 5. The hollow structure according to claim 1, wherein the dielectric layer is a hollow structure formed of an inner annular portion, an outer annular portion, and a connection portion connecting the two, and the hollow structure is formed of a fluorocarbon resin. The flat cable according to any one of the items.

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