JP2005093368A - Coaxial cable, apparatus for manufacturing coaxial cable and method of manufacturing coaxial cable - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a coaxial cable having a small diameter and excellent shielding performance, and the manufacturing method of the coaxial cable. <P>SOLUTION: In a coaxial cable 10 according to the present invention, a first insulating layer 12 of insulative material is provided along the periphery of a center conductor 11, a second insulating layer 12 of insulative material having small affinity to the insulative material of the first insulating layer 12 is provided along the periphery of the first insulating layer 12, and a shield layer 14 of metal thin film is provided along the periphery of the second insulating layer 13. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a coaxial cable, a manufacturing apparatus and a manufacturing method thereof, and more particularly to an ultrafine coaxial cable used for medical equipment, electronic information equipment, and the like, a manufacturing apparatus and a manufacturing method thereof.

  Among the coaxial cables, those having a very small outer diameter (for example, less than 0.35 mm) are referred to as micro coaxial cables. As shown in FIG. 5, the conventional general micro coaxial cable 50 is provided with an insulating layer 52 made of an insulator such as a fluororesin on the outer periphery of a central conductor (inner conductor) 51 formed by twisting strands. The outer periphery of the insulating layer 52 is provided with a shield layer (outer conductor) 53 and a jacket 54 formed by sequentially winding the strands. Here, the shield layer 53 shields electromagnetic noise in a high frequency region. Moreover, as a strand which comprises the center conductor 51 and the shield layer 53, the Cu-0.3mass% Sn alloy wire with a strand diameter of 0.03 mm etc. is used. Further, PFA or the like is generally used as the fluorine resin constituting the insulating layer 52, and PET or PFA or the like is generally used as the jacket 54.

  In recent years, demands for weight reduction, miniaturization, and thinning of medical devices and electronic information devices have been increasing, and further ultrafine coaxial cables have been demanded.

  Here, the central conductor 51 is a Cu-2 mass% Ag alloy wire having a strand diameter of 0.016 mm, the constituent material of the insulating layer 52 and the jacket 54 is PFA, and the shield layer 53 is a Cu having a strand diameter of 0.02 mm. There is an ultra-fine coaxial cable composed of -0.2mass% Sn-0.2mass% In alloy wire with an outer diameter of around 0.205mm.

  Further, since the ultrafine coaxial cable 50 having the structure shown in FIG. 5 has a limit in reducing the diameter, various ultrafine coaxial cables having different cable structures from the cable 50 have been proposed. For example, in the structure of the cable 50, there is a coaxial cable in which the central conductor is constituted by a single wire having a strand diameter of 0.08 mm (see, for example, Patent Document 1). Among the structures of the cable 50, there is a coaxial cable in which a shield layer is formed of a metal thin film (see, for example, Patent Documents 2 and 3).

Japanese Patent Laid-Open No. 2001-23456 Japanese Patent No. 2929161 JP 2002-203437 A

  However, the above-described micro coaxial cable having an outer diameter of about 0.205 mm is for a special purpose (for example, a cable connecting the main body of an ultrasonic endoscope and a probe), and its application range is limited. There was a problem that.

  Further, the coaxial cable described in Patent Document 1 has a problem that the outer diameter is 0.33 mm even with the thinnest diameter, and the effect of reducing the diameter is small.

  Furthermore, although the coaxial cable described in Patent Document 2 is highly effective in reducing the outer diameter of the cable, the manufacturing process is very complicated, resulting in an increase in manufacturing cost and a problem in mass productivity.

  Furthermore, although the coaxial cable described in Patent Document 3 is also highly effective in reducing the outer diameter of the cable, a shield layer (metal thin film) is directly formed on the surface of the insulating layer by metal plating. Therefore, when connecting the cable end of this coaxial cable, there was a problem that it was difficult to peel off the shield layer.

  An object of the present invention created in view of the above circumstances is to provide a coaxial cable having a small diameter and having a good shielding effect, a manufacturing apparatus thereof, and a manufacturing method.

  In order to achieve the above object, a coaxial cable according to the present invention is a coaxial cable having an insulating layer and a shield layer on an outer periphery of a center conductor, and a first insulating layer made of an insulator is provided on the outer periphery of the center conductor. A second insulating layer made of an insulator having a low affinity for the insulator constituting the first insulating layer is provided on the outer periphery of the insulating layer, and the shield layer made of a metal thin film is provided on the outer periphery of the second insulating layer.

  According to the above configuration, the first insulating layer, the second insulating layer, and the shield layer can be easily separated.

  In the coaxial cable according to the present invention, a coaxial cable having an insulating layer and a shield layer on the outer periphery of the center conductor is provided with a first insulating layer made of an insulator on the outer periphery of the center conductor, and the outer periphery of the first insulating layer. Further, the shield layer is formed of a conductive material having a small affinity for the insulator constituting the first insulating layer.

  According to the above configuration, the first insulating layer and the shield layer can be easily peeled off.

  According to the present invention, an excellent effect is obtained that a coaxial cable having a small diameter and having a sufficient shielding effect in a high frequency region can be obtained.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, a preferred embodiment of the invention will be described with reference to the accompanying drawings.

  FIG. 1 is a cross-sectional view of a coaxial cable according to a preferred embodiment of the present invention, and FIG. 3 is a cross-sectional view of a cable core used for manufacturing the coaxial cable of FIG. In FIG. 3, the same members as those in FIG.

  As shown in FIG. 1, the coaxial cable 10 according to the present embodiment includes a first insulating layer 12, a second insulating layer 13, a shield layer 14, and a jacket 15 in order on the outer periphery of the center conductor 11. It is. In other words, the coaxial cable 10 according to the present embodiment is formed by sequentially providing the shield layer 14 and the jacket 15 on the outer periphery of the cable core 30 shown in FIG.

  The first insulating layer 12 and the jacket 15 are preferably made of the same material. Examples of the constituent material include a fluororesin (for example, PFA). Moreover, as an insulator which comprises the 2nd insulating layer 13, a thing with small affinity with respect to the insulator which comprises the 1st insulating layer 12 is used. For example, when PFA is used as the constituent material of the first insulating layer 12, PET (polyethylene terephthalate) is used as the insulator constituting the second insulating layer 13. Furthermore, “small affinity” here means that, for example, the peel strength (peel strength) is 2.0 (N / 20 mm) or less, preferably 1.0 (N / 20 mm) or less. . The unit of N / 20 mm indicates the force (N) required for peeling 20 mm.

  Moreover, since the second insulating layer 13 is provided as a fixed layer of the shield layer 14 as described later, the thickness of the second insulating layer 13 is not particularly limited as long as the shield layer 14 can be sufficiently fixed. For example, it is sufficient if the thickness of the first insulating layer 12 is ½ or less, preferably ３ or less of the layer thickness.

  The shield layer 14 is intended to shield electromagnetic noise in a high frequency region, and is composed of a metal thin film. The thickness of the metal thin film is at least 1 μm, preferably 2 μm. When the thickness of the metal thin film is less than 1 μm, electromagnetic noise shielding is insufficient. Moreover, as a metal material which comprises a metal thin film, a material with high electrical conductivity is preferable, for example, Cu or Cu alloy, Ag or Ag alloy etc. are mentioned. Furthermore, the crystal grain size in the metal structure of the metal thin film is preferably adjusted to 0.5 μm or less. The crystal grain size is adjusted by adjusting the film forming conditions.

  The center conductor 11 may be either a stranded wire obtained by twisting strands or a single wire made of one strand. Examples of the stranded wire include those obtained by twisting a plurality of (7 in FIG. 1) Cu-2 mass% Ag alloy wires having a strand diameter of 0.016 mm. Moreover, as a single wire, the Cu-2mass% Ag alloy wire whose strand diameter is 0.04 mm is mentioned, for example.

  Next, a method for manufacturing the coaxial cable 10 according to the present embodiment will be described.

  As a method for forming a metal thin film on the surface of the resin (polymer material) constituting the insulating layer, an electroless plating method, a vacuum deposition method, an ion plating method, a sputtering method, etc. are generally known. In view of the film speed, among these methods, a sputtering process method having an excellent film forming speed is preferable.

  Conventionally, as an example of forming a metal thin film using a sputtering process, when a metal or insulating thin film is deposited (sputtering) on the surface of a resin sheet, surface roughening and vapor deposition using plasma treatment are performed. Some are performed in the same vacuum chamber (see, for example, Japanese Patent Application Laid-Open No. 2003-71985). However, this method can be applied if the object to be vapor-deposited is flat like a sheet, but a uniform metal thin film cannot be formed on the outer periphery of a wire such as a coaxial cable.

  Thus, as a result of intensive studies by the present inventors, a shield coating apparatus having an ion sputtering means capable of forming a uniform metal thin film on the outer periphery of a wire (cable core 30 (see FIG. 3)) has been developed. .

  As shown in FIG. 4, the shield coating apparatus 40 mainly includes a sending means (sending bobbin) 42 that sends out the wound cable core 30 and a surface roughening that applies a roughening process to the surface of the sent cable core 30. Forming means 44, ion sputtering means 45 that is provided downstream of surface roughening means 44 and forms a metal thin film as a shield layer on the outer periphery of cable core 30 whose surface is roughened, and a cable core that covers the shield layer And winding means (winding bobbin) 47 for winding 30. Pulleys 43a and 43b are provided between the means 42 and 44 and between the means 45 and 47, respectively.

  Each means 42, 44, 45, 47 is provided in a partition wall (pressure vessel) 41, and the partition wall 41 is provided with an exhaust device (vacuum pump) or the like (not shown) so that the inside can be maintained in a vacuum atmosphere. It is said.

  The ion sputtering means 45 includes a cylindrical sputter target member (electrode) 46 into which the cable core 30 having a rough surface is inserted, and one end of the central conductor in the sputter target member 46 and the cable core 30 (for example, FIG. 4, a DC power source 48 for applying a DC voltage is provided between the DC power supply 48 and an end portion on the sending means 42 side. The other end of the central conductor in the cable core 30 (for example, the end on the winding means 47 side in FIG. 4) is grounded to the ground 49.

  The coating process of the shield layer 14 (see FIG. 1) using the shield coating apparatus 40 described above is composed of two steps, a surface roughening step and a shield coating step.

  First, the first insulating layer 12 and the second insulating layer 13 are formed on the outer periphery of the central conductor 11 by extrusion coating or the like, and the cable core 30 is manufactured. The cable core 30 is wound around a sending means (sending bobbin) 42 in advance.

  Next, the cable core 30 wound up by the delivery means 42 is delivered and supplied to the surface roughening means 44 to perform a surface roughening process (surface roughening step). In the surface roughening means 44, the outer periphery of the cable core 30, that is, the outer periphery of the second insulating layer 13 is roughened by plasma of nitrogen gas or argon gas by glow discharge.

  Next, the cable core 30 subjected to the surface roughening treatment is continuously supplied to the ion sputtering means 45 provided at the subsequent stage of the surface roughening means 44 to perform shield coating (shield coating step).

  In the ion sputtering means 45, the cable core 30 travels through the inside of the cylindrical sputter target member 46. At this time, a DC voltage is applied between the target member 46 and the center conductor 11 (see FIG. 3) of the cable core 30 by the DC power supply 48, and the center conductor 11 is grounded to the ground 49. . Therefore, by applying a DC voltage, a metal sputtered thin film (shield layer 14 (see FIG. 1)) having a film thickness of about 0.1 to 0.3 μm is formed on the outer periphery of the cable core 30 over the entire periphery. Is done. Since the outer periphery of the cable core 30 is roughened by the surface roughening treatment, the metal sputtered thin film is firmly adhered to the outer periphery of the cable core 30. Here, the ion sputtering means 45 may be provided in multiple stages, and the metal sputtered thin film may be formed in multiple layers. This makes it possible to obtain a metal sputtered thin film having a thick film (for example, a film thickness of 1 μm or more).

  Thereafter, the shield-coated cable core 30 is wound around the winding means 47. Here, in the ion sputtering process, when a metal sputtered thin film having a sufficient thickness as the shield layer 14 cannot be obtained, the surface of the metal sputtered thin film is subjected to an electrolytic plating process or an electroless plating process after the sputtering process, and the entire metal thin film The film thickness may be 1 μm or more.

  Finally, the coaxial cable 10 shown in FIG. 1 is obtained by covering the outer periphery of the shield layer 14 having a sufficient thickness with the jacket 15 by extrusion coating or the like.

  Next, the operation of the coaxial cable 10 according to the present embodiment will be described.

  In the coaxial cable 10 according to the present embodiment, the second insulating layer 13 is provided on the outer periphery of the first insulating layer 12. The second insulating layer 13 is provided as a fixed layer of the shield layer 14. . Although the shield layer 14 is firmly adhered to the second insulating layer 13, the insulator constituting the second insulating layer 13 is configured with a low affinity for the insulator constituting the first insulating layer 12. . Therefore, the second insulating layer 13 itself can be easily separated from the first insulating layer 12 by hand without using a jig or the like.

  Therefore, the coaxial cable 10 according to the present embodiment can easily peel the second insulating layer 13 integrated with the shield layer 14 from the first insulating layer 12 when the terminal is connected. Workability at the time of connection becomes good.

  In the coaxial cable 10 according to the present embodiment, the crystal grain size of the metal structure in the metal thin film constituting the shield layer 14 is adjusted to 0.5 μm or less. Thereby, the toughness of the metal thin film can be improved. Therefore, the bending resistance of the metal thin film becomes good while being a thin film. As a result, the bending life of the coaxial cable 10 can be further improved.

  As described above, according to the coaxial cable 10 according to the present embodiment, a sufficient shielding effect (shielding effect) can be obtained in a high frequency region while having a small diameter (for example, an outer diameter of 0.200 mm or less), and The excellent effect that the peeling work at the time of terminal connection is easy is obtained.

  On the other hand, in the manufacturing apparatus 40 used for manufacturing the coaxial cable 10 according to the present embodiment, it is needless to say that the sputtering target is a sheet-like one. Even if it is a thing, a uniform metal sputtered thin film can be formed in the outer periphery.

  In addition, the number of steps required for manufacturing the coaxial cable 10 according to the present embodiment is only the first insulating layer 12, the second insulating layer 13, the shield layer 14 by the manufacturing apparatus 40, and the jacket 15 covering step. The coaxial cable 10 can be obtained in the manufacturing process. As a result, the manufacturing cost of the coaxial cable 10 according to the present embodiment can be reduced as compared with the coaxial cable described in Patent Document 2.

  Next, another embodiment of the present invention will be described with reference to the accompanying drawings.

  A cross-sectional view of a coaxial cable according to another embodiment of the present invention is shown in FIG. In addition, the same code | symbol is attached | subjected to the member similar to FIG.

  As shown in FIG. 2, the coaxial cable 20 according to the present embodiment has a first insulating layer 12, a shield layer 23, and a jacket 15 provided in order on the outer periphery of the center conductor 11.

  As a constituent material of the shield layer 23, a conductive material having a small affinity for the insulator constituting the first insulating layer 12 is used. Examples of the conductive material mentioned here include a conductive polymer exhibiting metallic or semiconductor conductivity, and an electrically conductive resin in which a conductor such as Cu, Ag, or graphite is dispersed in a polymer material. Examples of the conductive polymer include polyacetylene, polydiacetylene, polypyrrole, polyparaphenylene, polyparaphenylene sulfide, and the like, and polyacetylene is preferable. Moreover, as a polymeric material which comprises electrically conductive resin, PET, the conductive polymer mentioned above, a polyimide etc. are mentioned, for example.

  Since the shield layer 23 is intended to shield electromagnetic noise in the high frequency region, the thickness of the layer is appropriately selected according to the shielding effect required in the high frequency region. The layer thickness may be the same as that of the second insulating layer 13 shown in FIG.

  In the coaxial cable 20 according to the present embodiment, the first insulating layer 12 is provided on the outer periphery of the center conductor 11 to produce a cable core, and the shield layer 23 made of a conductive material is formed on the outer periphery of the cable core by an extrusion coating method. And the jacket 15 is provided on the outer periphery of the shield layer 23.

  Next, the operation of the coaxial cable 20 according to the present embodiment will be described.

  Also in the coaxial cable 20 according to the present embodiment, the same effects as those of the coaxial cable 10 according to the previous embodiment can be obtained.

  In addition, the coaxial cable 20 according to the present embodiment is provided with the jacket 15 directly on the outer periphery of the shield layer 23 serving as the second insulating layer and the shield layer, and the second coaxial cable 10 according to the previous embodiment. The insulating layer 13 is not required. Therefore, the coaxial cable 20 according to the present embodiment can be further reduced in diameter as compared with the coaxial cable 10 according to the previous embodiment.

  Further, although the shield layer 23 of the coaxial cable 20 according to the present embodiment has a sufficient shielding effect as the shield layer, the shield layer 14 (second shield layer) shown in FIG. ) May be provided. As a result, the coaxial cable 20 according to the present embodiment can further improve the shielding effect while maintaining the same outer diameter as compared with the coaxial cable 10 according to the previous embodiment.

  As mentioned above, it cannot be overemphasized that embodiment of this invention is not limited to embodiment mentioned above, and various things are assumed in addition.

  Next, embodiments of the present invention will be described based on examples, but the embodiments of the present invention are not limited to these examples.

(Example 1)
As the central conductor, a twisted wire material in which seven strands of Cu-2 mass% Ag alloy wire having a strand diameter of 0.016 mm are twisted, and the outer periphery of the central conductor is configured with a PFA film having a thickness of 0.033 mm in order. A first insulating layer, a second insulating layer composed of a PET film having a thickness of 0.01 mm, a shield layer composed of an Ag film having a thickness of 2 μm (0.002 mm), and a PFA film having a thickness of 0.025 mm An ultrafine coaxial cable having an outer diameter of 0.188 mm was manufactured by covering the constructed jacket.

(Example 2)
A first insulating layer composed of a PFA film having a thickness of 0.033 mm, a shield layer composed of a polyacetylene film having a thickness of 0.01 mm, and a thickness of 0.025 mm on the outer periphery of the same central conductor as in Example 1. A fine coaxial cable having an outer diameter of 0.184 mm was manufactured.

(Example 3)
A first insulating layer composed of a PFA film having a thickness of 0.033 mm, a shield layer composed of a polyacetylene film having a thickness of 0.01 mm, and a thickness of 2 μm (0. A fine coaxial cable having an outer diameter of 0.188 mm was manufactured by covering a second shield layer made of a 002 mm) Ag film and a jacket made of a PFA film having a thickness of 0.025 mm.

Example 4
As the center conductor, a Cu-2 mass% Ag alloy single wire having a strand diameter of 0.040 mm is used, and a first insulating layer composed of a PFA film having a thickness of 0.028 mm is formed on the outer periphery of the center conductor in order. Covers a second insulating layer composed of a PET film with a thickness of 0.01 mm, a shield layer composed of an Ag film with a thickness of 2 μm (0.002 mm), and a jacket composed of a PFA film with a thickness of 0.025 mm An ultrafine coaxial cable having an outer diameter of 0.170 mm was manufactured.

(Example 5)
A first insulating layer composed of a PFA film having a thickness of 0.028 mm, a shield layer composed of a polyacetylene film having a thickness of 0.01 mm, and a thickness of 0.025 mm on the outer periphery of the same central conductor as in Example 4. A jacket composed of a PFA film was coated to produce an ultrafine coaxial cable having an outer diameter of 0.166 mm.

(Example 6)
A first insulating layer composed of a PFA film having a thickness of 0.028 mm, a shield layer composed of a polyacetylene film having a thickness of 0.01 mm, and a thickness of 2 μm (0. A fine coaxial cable having an outer diameter of 0.170 mm was manufactured by covering a second shield layer composed of a 002 mm) Ag film and a jacket composed of a PFA film having a thickness of 0.025 mm.

(Comparative Example 1)
A first insulating layer made of a PFA film having a thickness of 0.033 mm is coated on the outer periphery of the same central conductor as in the first embodiment. On the outer periphery of the first insulating layer, a Cu-0.2 mass% Sn-0.2 mass% In alloy wire having an element wire diameter of 0.016 mm is horizontally wound to form a shield layer. The outer periphery of the shield layer was covered with a jacket made of a PFA film having a thickness of 0.025 mm, and an ultrafine coaxial cable having an outer diameter of 0.197 mm was manufactured.

  The coaxial cables of Examples 1 to 6, which are coaxial cables according to the present invention, were able to reduce the cable outer diameter by 4.5% or more compared to the coaxial cable of the comparative example.

  In addition, the coaxial cables of Examples 1 to 6 were able to obtain a sufficient shielding effect in the high frequency region even though the outer diameter was as small as 0.166 to 0.188 mm (for example, from 10 MHz to 0.1 to 0.5 dB in the frequency range of 1 GHz).

  Further, the second insulation layer is used for the coaxial cables of Examples 1 and 4, the shield layer is used for the coaxial cables of Examples 2, 3, 5, and 6, and the first insulation layer is used without using a jig or the like. It could be easily peeled off by work.

  Further, as in the coaxial cables of Examples 4 to 6, by using a single wire instead of a stranded wire as the central conductor, the outer diameter of the cable is reduced compared to the coaxial cables of Examples 1 to 3 (maximum About 16%).

  The coaxial cable according to the present embodiment is suitable as a signal transmission and connection cable for medical devices such as diagnostic probes and endoscopes of ultrasonic diagnostic apparatuses, and information devices such as portable information terminals and notebook computers. Besides these, it can also be applied as a signal transmission cable for industrial robots and the like.

1 is a cross-sectional view of a coaxial cable according to a preferred embodiment of the present invention. It is a cross-sectional view of a coaxial cable according to another preferred embodiment of the present invention. It is a cross-sectional view of the cable core used for manufacture of the coaxial cable of FIG. It is the schematic of the shield coating apparatus used for manufacture of the coaxial cable which concerns on preferable one Embodiment of this invention. It is a cross-sectional view of a conventional coaxial cable.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Coaxial cable 11 Center conductor 12 1st insulating layer 13 2nd insulating layer 14 Shield layer

Claims (9)

  In a coaxial cable having an insulating layer and a shield layer on the outer periphery of the central conductor, a first insulating layer made of an insulator is provided on the outer periphery of the central conductor, and the first insulating layer is formed on the outer periphery of the first insulating layer. A coaxial cable comprising a second insulating layer made of an insulator having a low affinity for a body, and the shield layer made of a metal thin film provided on the outer periphery of the second insulating layer.   The coaxial cable according to claim 1, wherein a crystal grain size of the metal structure of the metal thin film is 0.5 µm or less.   In a coaxial cable having an insulating layer and a shield layer on the outer periphery of the central conductor, a first insulating layer made of an insulator is provided on the outer periphery of the central conductor, and the first insulating layer is formed on the outer periphery of the first insulating layer. A coaxial cable comprising the shield layer made of a conductive material having a low affinity for a body.   The coaxial cable according to claim 3, wherein the conductive material is a conductive polymer or an electrically conductive resin.   In a coaxial cable manufacturing apparatus in which an insulating layer and a shield layer are provided on the outer periphery of the central conductor, a sending means for sending out the cable core having the insulating layer provided on the outer periphery of the central conductor, and the surface of the sent cable core A surface roughening means for performing a roughening treatment on the surface, an ion sputtering means for forming a metal thin film as the shield layer on the outer periphery of the cable core having a roughened surface provided on the surface of the surface roughening means, and a shield layer A coaxial cable manufacturing apparatus, comprising: a winding means for winding a cable core coated with a cable.   The ion sputtering means includes a cylindrical sputter target member into which the cable core whose surface has been roughened is inserted, and a DC power source that applies a DC voltage between the sputter target member and the central conductor of the cable core. The apparatus for manufacturing a coaxial cable according to claim 5.   In the method of manufacturing a coaxial cable in which an insulating layer and a shield layer are provided on the outer periphery of the central conductor, a first insulating layer made of an insulator is provided on the outer periphery of the central conductor, and the first insulating layer is provided on the outer periphery of the first insulating layer. A second insulating layer made of an insulator having a low affinity for the constituting insulator is provided, and then the surface of the second insulating layer is roughened with the central conductor grounded using the manufacturing apparatus according to claim 5 or 6. A method for manufacturing a coaxial cable, comprising: performing a treatment, performing an ion sputtering treatment continuously to the surface roughening treatment, and providing the shield layer with a metal thin film on the outer periphery of the second insulating layer.   8. The method of manufacturing a coaxial cable according to claim 7, wherein after the sputtering treatment, electrolytic plating treatment or electroless plating treatment is performed to form the metal thin film into a thick film. In the method of manufacturing a coaxial cable in which an insulating layer and a shield layer are provided on the outer periphery of the central conductor, a first insulating layer made of an insulator is provided on the outer periphery of the central conductor, and the first insulating layer is provided on the outer periphery of the first insulating layer. A method for manufacturing a coaxial cable, comprising: providing the shield layer with a conductive material having a low affinity for a constituent insulator.

Images