JP2002352641A - Flat two-core coaxial cable with built-in spacer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flat two-core coaxial cable with a built-in spacer, which can be easily connected to a connector and a circuit board. SOLUTION: In the flat two-core coaxial cable, two pieces of core made of an internal conductor 1 and an insulator 2 coating the internal conductor 1, are arranged in parallel. The two piece of core are covered with an outer conductor 3, which is covered with a jacket 4. A spacer 5 is inserted between two pieces of core to increase the distance between two of the internal conductors. A line-pitch is increased previously by the spacer 5 and so the line-pitch coincides with the pitch between the conductors of the connector and the circuit board.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a two-core parallel coaxial cable suitable for a signal line of information equipment, and more particularly to a two-core parallel coaxial cable containing a spacer which can be easily connected to a connector and a circuit board. .

[0002]

2. Description of the Related Art A signal line (including a power supply line) for electrically connecting a main body of a notebook computer and a liquid crystal screen is wired through a hinge portion for connecting the main body and the liquid crystal screen to be freely opened and closed.
When arranging this signal line, an ultrafine coaxial cable having a conductor size of 32 AWG or less, which is ultrafine and has excellent electrical characteristics, is used. Micro coaxial cables are used for the number of cores required for signals. At this time, since the transmission method is differential transmission (a method in which one signal is represented by the potential difference between two signal lines), the number of cores is an even number. A two-core parallel coaxial cable may be used for the signal line in order to improve transmission characteristics. Conventional two-core parallel coaxial cable,
Two cores each having an inner conductor covered with an insulator are arranged in parallel in contact with each other, and an outer conductor and a jacket are formed around these cores. Whichever cable is used, the signal line is connected to a connector or a circuit board.

[0003]

The pitch between the conductors of the conductor connecting portions of the connector and the circuit board is generally 0.5 mm.
Or it is 1.0 mm. The pitch between signal lines must be matched to the pitch between conductors. When a two-core parallel coaxial cable is used for a signal line in order to improve the transmission characteristics, the line pitch (inter-conductor pitch) of the two-core parallel coaxial cable is usually different from the conductor pitch of the connector and the circuit board. . For this reason, at the time of the connection work, it is necessary to perform processing to increase the line pitch of the terminals of the two-core parallel coaxial cable, which requires time and effort.

In the conventional two-core parallel coaxial cable, the pitch between the inner conductors is defined by the core diameter, and the characteristic impedance between the cores cannot be changed as desired.

Accordingly, an object of the present invention is to solve the above-mentioned problems and to provide a two-core parallel coaxial cable containing a spacer which can be easily connected to a connector and a circuit board.

[0006]

According to the present invention, two cores each having an inner conductor covered with an insulator are arranged in parallel, and an outer conductor and a jacket are formed around these cores. In the two-core parallel coaxial cable described above, a spacer is inserted between the two cores to increase the distance between the internal conductors.

In a two-core parallel coaxial cable in which two cores each having an inner conductor covered with an insulator and an outer conductor are arranged in parallel and a jacket is formed around these cores, an inner conductor is provided between the two cores. A spacer for increasing the distance may be inserted.

It is preferable that the characteristic impedance between the two cores is constant in the longitudinal direction. This is effective when the size of the inner conductor is 32 AWG (outer diameter of about 0.24 mm) or less.

[0009] The insulator may be made of any of polyethylene, polypropylene, ETFE, PFA, FEP, PTFE, and fluoro rubber.

[0010] The spacer may be made of any of polyethylene, polypropylene, ETFE, PFA, FEP, PTFE and fluoro rubber.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a first embodiment of the present invention will be described in detail with reference to the accompanying drawings.

As shown in FIG. 1, in this two-core parallel coaxial cable, two cores (insulated wire cores) each having an inner conductor 1 covered with an insulator 2 are arranged in parallel with a spacer 5 interposed therebetween. The outer conductor 3 and the jacket 4 are formed around the core and the spacer 5. The spacer 5
As shown in the figure, the cross section is rectangular, and is formed uniformly in the longitudinal direction.

For example, a 36 AWG (outer diameter of about 0.15 mm) tin-plated copper alloy wire is used as the inner conductor 1 and a PFA resin (ethylene tetrafluoride / perfluoroalkoxy) is used as an insulator 2 around the inner conductor 1. A PFA resin insulator extruded from the polymer is provided to form an insulating core having an insulator outer diameter of 0.25 mm.

The thickness between these two insulated wires is about 0.1
By arranging the insulated wires in parallel while inserting a spacer 5 of 25 mm and a width of about 0.25 mm, the pitch between the inner conductors of the two insulated wires becomes 0.5 mm.

Around the two insulated wires and the spacer 5, the outer conductor 3 has a wire diameter of 0.03 mm and a thickness of 0.3 mm.
A 08 mm shield is applied, and a polyester tape is wound around the outer conductor 3 as a jacket 4.

The two-core parallel coaxial cable has a spacer 5
Since the pitch between lines has been widened to 0.5 mm in advance by the insertion, the pitch between conductors matches the pitch between conductors of the connector and the circuit board. Therefore, at the time of the connection work, there is no need to perform processing for increasing the line pitch of the terminals, and no labor is required.

The characteristic impedance between the two insulated wires is determined by the pitch between the internal conductors, the size and permittivity of the insulator 2, the size and permittivity of the spacer 5, and the like.
Therefore, the dimensions and permittivity of the spacer 5 should be selected so as to conform to the characteristic impedance required by the information equipment for laying the cable. Thereby, the characteristic impedance required for the signal line is obtained. And
Since the two-core parallel coaxial cable of the present invention has a uniform structure in the longitudinal direction, the characteristic impedance is constant in the longitudinal direction.

Next, a second embodiment of the present invention will be described in detail with reference to the accompanying drawings.

As shown in FIG. 2, in this two-core parallel coaxial cable, two cores (insulated wire cores) each having an inner conductor 1 covered with an insulator 2 and further covered with an outer conductor 3 are provided with a spacer 5. Are arranged in parallel with each other, and these cores and spacers 5
Is formed around the jacket 4. The spacer 5 has a rectangular cross section as shown, and is formed uniformly in the longitudinal direction.

For example, a 40 AWG (outer diameter of about 0.09 mm) tin-plated copper alloy wire is used as the inner conductor 1, and a PFA resin insulator extruded from a PFA resin is provided as an insulator 2 around the inner conductor 1. An insulating wire core having an insulator outer diameter of 0.25 mm is formed, and a tin-plated copper wire is horizontally wound around the insulating wire core as the external conductor 3 to form a core.

At this time, since the outer diameter of the core is about 0.31 mm, the two cores are arranged in parallel while inserting a spacer 5 having a thickness and a width of about 0.19 mm between the two cores. The pitch between the inner conductors of the core is 0.5 mm.

A polyester tape is wound around the two cores and the spacer 5 as the jacket 4.

This two-core parallel coaxial cable has a spacer 5
Since the pitch between lines has been widened to 0.5 mm in advance by the insertion, the pitch between conductors matches the pitch between conductors of the connector and the circuit board. Therefore, at the time of the connection work, there is no need to perform processing for increasing the line pitch of the terminals, and no labor is required.

As for the characteristic impedance between the two insulated wires, the dimensions and permittivity of the spacer 5 may be selected so as to conform to the characteristic impedance required by the information equipment for laying the cable. Thereby, the characteristic impedance required for the signal line is obtained.

In the above two embodiments, PFA is used for the insulator 2. However, polyethylene, polypropylene, ETFE (ETFE resin; ethylene tetrafluoroethylene copolymer), FEP (FEP resin) ;
Ethylene tetrafluoride / propylene hexafluoride copolymer), P
It is good to use it by selecting from TFE (PTFE resin; polytetrafluoroethylene), fluorine rubber and the like.

The material of the spacer 5 was not specified, but polyethylene, polypropylene, ETF
It is good to use by selecting from E, PFA, FEP, PTFE, fluororubber and the like.

Further, although 36 AWG and 40 AWG are used as the internal conductor 1, any material may be used as long as it is thinner than 32 AWG.

[0028]

The present invention exhibits the following excellent effects.

(1) Since the line pitch is secured by the spacer, connection to the connector and the circuit board is easy.

(2) Since the pitch between lines is constant in the longitudinal direction by the spacer, the characteristic impedance between the lines is constant in the longitudinal direction.

(3) Since the characteristic impedance between lines can be changed by the dielectric constant of the spacer, a two-core parallel coaxial cable having a desired characteristic impedance required for information equipment can be manufactured.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a two-core parallel coaxial cable showing a first embodiment of the present invention.

FIG. 2 is a sectional view of a two-core parallel coaxial cable showing a second embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Internal conductor 2 Insulator 3 External conductor 4 Jacket 5 Spacer

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Hirohiro Tanaka 5-1-1, Hidaka-cho, Hitachi City, Ibaraki Prefecture F-term in the Hidaka Plant of Hitachi Cable, Ltd. (reference) 5G319 FA10 FB01 FC37

Claims (6)

[Claims] 1. A two-core parallel coaxial cable in which two cores each having an inner conductor covered by an insulator are arranged in parallel, and an outer conductor and a jacket are formed around these cores. A two-core parallel coaxial cable containing a spacer, wherein a spacer for increasing a distance between inner conductors is inserted. 2. A two-core parallel coaxial cable in which two cores each having an inner conductor covered by an insulator and an outer conductor are arranged in parallel, and a jacket is formed around these cores. A two-core parallel coaxial cable containing a spacer, wherein a spacer for increasing a distance between inner conductors is inserted. 3. The two-core parallel coaxial cable containing a spacer according to claim 1, wherein a characteristic impedance between the two cores is constant in a longitudinal direction. 4. The two-core parallel coaxial cable containing a spacer according to claim 1, wherein the size of the inner conductor is 32 AWG or less. 5. The two-core parallel coaxial cable containing a spacer according to claim 1, wherein the insulator is made of any one of polyethylene, polypropylene, ETFE, PFA, FEP, PTFE, and fluoro rubber. 6. The method according to claim 1, wherein the spacer is made of any one of polyethylene, polypropylene, ETFE, PFA, FEP, PTFE, and fluoro rubber.
A two-core parallel coaxial cable containing a spacer according to any one of the above.