JP2003086030A - Extrafine coaxial cable - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide extrafine coaxial cable having sufficient flexibility and electrical properties. SOLUTION: In extrafine coaxial cable 1 provided with inner conductive body 2, insulating body 3 covering outer circumference of the inner conductive body 2, outer conductive body 4 wound around the outer circumference of the insulating body 3, plastic tape 6 with metal layer wound around outer circumference of the outer conductive body 4 and having metal layer 5 formed on a surface which the outer conductive body 4 gets into contact with, and jacket 7 covering outer circumference of plastic tape, the metal layer 5 of the plastic tape with metal layer is formed with plating layer of cupper of thickness 0.5-8 μm, aluminum of thickness 0.5-0.4 μm, or silver of thickness 0.5-4 μm.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a micro coaxial cable used for connecting a main body of a notebook computer and a liquid crystal screen (LCD) through a hinge portion.

[0002]

2. Description of the Related Art As shown in FIG. 4, there is a coaxial cable 20 in which a plastic tape 21 having a metal layer is wound around the outer conductor 4 in order to improve electric characteristics such as a shield effect and an attenuation amount. .

The plastic tape 21 with a metal layer is
For the coaxial cable 20 having a relatively large outer diameter, a plastic tape 22 to which a metal foil 23 is bonded is used. Generally, the metal foil 23 is copper having a thickness of 8 μm or more, and aluminum or silver having a thickness of 4 μm or more. Is formed.

The outer diameter is 1 mm or less (conductor size 36
In the case of a micro coaxial cable (not shown) of an AWG (American Wire Gauge) (thinner diameter is about 0.13 mm), if the plastic tape 21 with the metal layer described above is used, a thick metal foil 23 causes Since the flexibility of the cable is significantly impaired, a metal layer-attached plastic tape (not shown) formed by depositing metal on the plastic tape 22 is used.

The formation of a metal layer by vapor deposition is generally time consuming and the thickness of the vapor deposited metal layer (not shown) is less than 0.
1 to 0.5 μm, 0.05 to 0.5 μm for aluminum
Has become.

[0006]

However, since the vapor-deposited metal layer is thin, there is a problem that sufficient electrical characteristics cannot be obtained.

Therefore, an object of the present invention is to solve the above problems and provide a micro coaxial cable having sufficient flexibility and electric characteristics.

[0008]

In order to achieve the above object, the present invention provides an inner conductor, an insulator covering the outer periphery of the inner conductor, and an outer conductor wound around the outer periphery of the insulator.
A micro coaxial cable comprising: a plastic tape with a metal layer, which is wound around the outer circumference of the outer conductor and has a metal layer formed on at least the surface in contact with the outer conductor; and a jacket covering the outer circumference of the plastic tape with the metal layer. ,
The thickness of the metal layer of the plastic tape with the metal layer is 0.
It is formed of a plated layer of copper having a thickness of 5 to 8 μm, aluminum having a thickness of 0.5 to 0.4 μm, or silver having a thickness of 0.5 to 4 μm.

The metal layer can be easily formed to an intermediate thickness that is thinner than the metal foil and thicker than the vapor-deposited metal layer, and sufficient flexibility and sufficient electrical characteristics can be obtained.

A plurality of microfine coaxial cables may be twisted together to form a coaxial multicore cable.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

As shown in FIG. 1, a micro coaxial cable 1
Is the inner conductor 2, the insulator 3 that covers the outer periphery of the inner conductor 2, the outer conductor 4 that is wound around the outer periphery of the insulator 3, the outer conductor 4 that is wrapped around the outer conductor, and the inner and outer surfaces thereof. Plastic tape 6 with a metal layer on which the metal layer 5 is formed
And a jacket 7 that covers the outer periphery of the plastic tape 6 with a metal layer.

The inner conductor 2 is formed by tin-plating a single wire made of a high-strength copper alloy, and has a conductor size of 40 AWG (outer diameter of about 0.09 mm). Tin plating is performed to improve the bending characteristics and terminal solderability of the internal conductor 2, and may be replaced with silver plating, nickel plating, or the like. In particular, silver plating has excellent electrical characteristics, and nickel plating has excellent corrosion resistance.

The insulator 3 is made of PFA resin (Copolymer of T
etrafluoroethylene and Perfluoroalkoxy: tetrafluoroethylene / perfluoropropyl vinyl ether copolymer)
The inner conductor 2 and the insulator 3 form an insulating wire core 8 having an insulator outer diameter of 0.25 mm.

The outer conductor 4 is formed by horizontally winding a tin-plated copper wire having a wire diameter of 0.032 mm on the insulator 3.
It forms a shield conductor.

The plastic tape 6 with a metal layer has a thickness of 4
It is formed by plating copper with a thickness of 4 μm on both sides of a μm polyester tape 9.

The thickness of the copper plating as the metal layer 5 is 0.5 to
Within the range of 8 μm, flexibility and electric characteristics can be obtained in a good balance. However, more preferably 2 to
A range of 5 μm is preferable.

The metal layer 5 may be formed by aluminum plating or silver plating other than copper plating. In the case of aluminum plating or silver plating, the thickness may be within the range of 0.5 to 4 μm (preferably 2 to 4 μm).

The jacket 7 is formed by winding a polyester tape around the plastic tape 6 with a metal layer.

Further, as shown in FIG. 2, a plurality of microfine coaxial cables 1 are twisted together to form a coaxial multicore cable 10.

Next, the operation will be described.

When the plastic tape 6 with the metal layer is manufactured, the polyester tape 9 is formed by the hot dip plating method.
Apply copper plating to the surface of. A thicker metal layer 5 can be formed in a shorter time than in the case of forming a metal layer by vapor deposition, and a uniform plating layer having a thickness of 4 μm can be easily obtained by performing finish polishing.

Since the micro coaxial cable 1 constructed by including the plastic tape 6 with the metal layer has the thickness of the metal layer 5 which is 4 μm thicker than that of the metal layer formed by vapor deposition, good electric characteristics can be obtained. You can

Table 1 shows the results of experiments conducted on the shielding effect and the attenuation amount, which are electrical characteristics.

[0025]

[Table 1]

In the experiment, the shield effect in the high frequency band of 0.1 to 1 GHz was measured, and the attenuation amount per unit length was 100 MHz, 250 MHz and 500 MHz.
Was measured in each of the high frequency bands.

The "conventional product" in the table means that the metal layer of the plastic tape 6 with a metal layer has a thickness of 0.1 to 0.
It means a micro coaxial cable formed in 5 μm, and the “invention product” is a micro coaxial cable 1 in which a metal layer 5 is formed by plating to a thickness of 4 μm (the metal layers are all made of copper). ).

From Table 1, it can be seen that the product of the present invention is superior to the conventional product in both the shield effect and the attenuation amount.

When the metal layer 5 is formed by plating,
It can be easily formed thinner than the metal foil 23, and sufficient flexibility can be obtained.

As described above, the inner conductor 2, the insulator 3 covering the outer periphery of the inner conductor 2, the outer conductor 4 wound around the outer periphery of the insulator 3, and the outer conductor 4 wound on the outer periphery of the metal In the microfine coaxial cable 1 including the plastic tape 6 with a metal layer formed with the layer 5 and the jacket 7 that covers the outer circumference of the plastic tape 6 with the metal layer, the metal layer 5 of the plastic tape 6 with the metal layer is thickened. 0.5-8 μm
Since it is formed of a copper or aluminum plating layer having a thickness of 0.5 to 0.4 μm or a silver plating layer having a thickness of 0.5 to 4 μm, sufficient flexibility and sufficient electrical characteristics can be obtained at the same time.

Since a plurality of microfine coaxial cables 1 are twisted together to form the coaxial multicore cable 10, it is possible to obtain the coaxial multicore cable 10 excellent in flexibility and electric characteristics.

Although the insulator 3 is made of PFA resin, it is not limited to this. For example, FEP
Resin (Copolymer of Tetrafluoroethylene and Hexaflu
oropropylene: tetrafluoroethylene / hexafluoropropylene copolymer) or PTFE resin (Copolymer of Ethylene)
Fluorine resin such as and Tetrafluoroethylene: ethylene / tetrafluoroethylene copolymer).

Further, although the micro coaxial cable 1 having a single insulating wire core 8 has been described, as shown in FIG. 3, a plurality of insulating wire cores 8 are arranged in parallel and the outer circumference of these insulating wire cores 8 is arranged. A micro coaxial cable 13 of a type in which the outer conductor 11 is wound and a plastic tape 12 with a metal layer is wound around the outer conductor 11 may be used.

Although the micro coaxial cable 1 having the conductor size of 40 AWG has been described, the present invention is not limited to this. Conductor size 36, which is generally called micro coaxial cable
The same effect can be obtained if the coaxial cable is thinner than the AWG (outer diameter of about 0.13 mm).

The metal layer 5 of the plastic tape 6 with the metal layer is formed on both sides of the polyester tape 9, but it may be formed only on the side in contact with the outer conductor 4.

[0036]

In summary, the present invention has the following excellent effects. (1) Sufficient flexibility and electrical characteristics can be obtained in a micro coaxial cable.

[Brief description of drawings]

FIG. 1 is a perspective view of a micro coaxial cable showing a preferred embodiment of the present invention.

FIG. 2 is a perspective view of a coaxial multicore cable.

FIG. 3 is a perspective view of a micro coaxial cable showing another embodiment.

FIG. 4 is a perspective view of a conventional microfine coaxial cable.

[Explanation of symbols]

1 Micro coaxial cable 2 inner conductor 3 insulator 4 outer conductor 5 metal layers 6 Plastic tape with metal layer 7 jacket 10 Coaxial multi-core cable 11 outer conductor 12 Plastic tape with metal layer 13 Micro coaxial cable

Claims (2)

[Claims] 1. An inner conductor, an insulator covering the outer periphery of the inner conductor, an outer conductor wound around the outer periphery of the insulator, and a surface of the outer conductor which is wound around the outer periphery and contacts at least the outer conductor. In a microfine coaxial cable comprising a metal layer-coated plastic tape having a metal layer formed thereon and a jacket covering the outer periphery of the metal layer-coated plastic tape, the metal layer of the metal layer-coated plastic tape has a thickness of 0. 5-8
A micro coaxial cable, which is formed of a plated layer of copper having a thickness of 0.5 μm, aluminum having a thickness of 0.5 to 0.4 μm, or silver having a thickness of 0.5 to 4 μm. 2. A coaxial multi-core cable formed by twisting a plurality of the fine coaxial cables.