JP3299172B2 - Communication cable - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication cable provided with measures against electromagnetic noise and static noise.

[0002]

2. Description of the Related Art When transmitting analog or digital signals such as audio information and video information, generally use a communication cable provided with measures against external electromagnetic noise or a communication cable provided with measures against electrostatic noise. ing.

As a measure against electrostatic noise caused by rubbing of a core wire inside a cable with an insulating coating material, for example, a conductive vinyl material or carbon tape containing carbon is arranged inside a shield material in the cable. There is a cable that has been used.

As a measure against external electromagnetic noise induced to a cable, a cable in which a ferrite core, for example, is fitted around the cable is known. Further, as means for suppressing self-noise emission from the cable itself, a plurality of independent, for example, double shield layers are provided inside the cable, and the outer shield layer is connected to the ground to improve the shielding property. Methods are also known.

[0005]

By the way, if both electromagnetic noise and electrostatic noise are to be suppressed,
Conventionally, the above-described noise countermeasures are individually and appropriately combined. However, according to this, the configuration of the communication cable is complicated, and the communication cable cannot be applied to a general-purpose cable. There was a problem that it would be high.

Further, even if the noise countermeasures are individually combined, the effect of noise suppression is not expected. In addition, the market demands cables that are easy to handle, but it is also necessary to connect each wire to the ground, which complicates the handling of the cables. It is pointed out.

The present invention has been made to solve such a problem, and an object of the present invention is to provide a communication cable capable of preventing both electromagnetic noise and electrostatic noise with a simple configuration. Is what you do.

[0008]

[0009]

In order to achieve the above object, the present invention provides a signal line, a shield layer provided around the signal line via an internal insulator, and formed on the shield layer. In a communication cable having an external insulator, a plastic tape is used as a base between the shield layer and the external insulator, and one surface of the base has a function of an electrostatic noise filter. A noise filter tape having the function of an electromagnetic noise filter is wound on the other surface so that one surface of the noise filter tape is electrically in contact with the shield layer.

In this case, preferably, the electrostatic noise filter formed on one surface of the substrate is formed of a conductive treatment layer, and the electromagnetic noise filter formed on the other surface is formed of an iron oxide treatment layer. Consists of

The conductive treatment layer can be formed, for example, by applying carbon to the base tape. The iron oxide treatment layer can be formed by applying, for example, a cobalt-based material, which is an iron oxide material, to the base tape. It can be formed by vapor deposition.

According to the present invention, since the conductive processing layer is in contact with the shield layer, the conductivity suppresses electrostatic noise generated inside the cable. In addition, for example, electromagnetic noise from the outside such as a fluorescent lamp generates an eddy current in the iron oxide-based processing layer, and its heat loss suppresses intrusion into the signal line.

Further, according to the present invention, it is only necessary to wind the noise filter tape on the shield layer, so that the manufacturing is easy and the cost is advantageous. In addition, a low-grade communication cable can not only easily take measures against electrostatic noise and electromagnetic noise, but also does not need to be separately grounded, so that a cable suitable for simple connectivity can be provided. .

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, preferred embodiments of the present invention will be described with reference to the drawings for better understanding of the technical concept of the present invention.

FIG. 1 is a partially developed view of a communication cable 1 according to the present invention. According to this, this communication cable 1
Denotes a signal line 2 and an internal insulator 3 covering the signal line 2
A shield layer 4 made of, for example, a metal braid, provided around the internal insulator 3, a noise filter tape 5 wound on the shield layer 4, and a noise filter tape 5 formed on the noise filter tape 5. And an external insulator (sheath) 6.

In this embodiment, the signal line 2 is an insulator 2
a of the core wire conductor 2b covered with a.
Although the wire is shown as a stranded wire, it may be a single wire.
In the case of a single wire, one of the insulator 2a and the inner insulator 3 can be omitted. In the case of two wires as shown in FIG. 1, since the insulator 2a is provided on the core conductor 2b, the internal insulator 3 side may be omitted.

As shown in the cross-sectional view of FIG. 2, the noise filter tape 5 includes a base material 5a made of a thin and flexible plastic tape having a predetermined width, and one surface of the base material 5a. Is provided with a conductive processing layer 5b functioning as an electrostatic noise filter. In this embodiment, the conductive treatment layer 5b is formed by applying a conductive resin containing carbon powder to a predetermined thickness.

On the other surface of the substrate 5a, an iron oxide-based treatment layer 5c functioning as an electromagnetic noise filter is provided. In this embodiment, a cobalt-based material is used for the iron oxide-based treatment layer 5c.

FIG. 3 shows the noise filter tape 5
FIG. 1 is an enlarged sectional view of the communication cable 1 provided with a conductive filter layer 5b.
Side is electrically in contact with the shield layer 4 and the iron oxide-based treatment layer 5c
Is wound on the shield layer 4 so that the outer side is located outside.

According to this configuration, since the conductive processing layer 5b of the noise filter tape 5 is in electrical contact with the shield layer 4, electrostatic noise generated inside the cable is suppressed. Further, for example, external electromagnetic noise from a fluorescent lamp or the like generates an eddy current in the iron oxide-based processing layer 5c of the noise filter tape 5, and its heat loss suppresses entry into a signal.

Next, the noise resistance of the communication cable according to the present invention will be described. As a sample 1, a communication cable 1 having the noise filter tape 5 according to the present invention shown in FIG. 1 was prepared. The overall thickness of the noise filter tape 5 is 13 μm, and the thickness of the iron oxide-based treatment layer (cobalt-based material) is 3 to 5 μm.

As a sample 2 to be compared with this, a so-called noise-free countermeasure communication cable A obtained by removing the noise filter tape 5 from the communication cable 1 according to the present invention shown in FIG. 1 was used. A communication cable B in which a ferrite core was fitted to the outer periphery of the communication cable A of the sample 2 was used.

A wide-band noise generator is arranged near the communication cable of each of the samples 1 to 3, and a noise is applied from the noise generator in the range of 1 kHz to 30 MHz. The noise contamination level was measured with a spectrum analyzer.

As a result, the noise mixing level of Sample 1 (product of the present invention) was 22 dBm. On the other hand, sample 2
(No noise countermeasure product) noise mixing level is 29dBm,
The noise mixing level of Sample 3 (product with a ferrite core) was 22 dBm.

From this, it was confirmed that the sample of the present invention of sample 1 has the noise filter effect improved by -7 dBm as compared with the sample 2 with no noise countermeasure, similarly to the sample 3 with the ferrite core.

That is, according to the present invention, while being equivalent in performance to a cable having a noise filter effect by a ferrite core, the productivity is good, the appearance is smart, and there is no need to take a special ground. For example, it is possible to provide a communication cable having excellent handleability.

[0027]

As described above, according to the present invention,
With a very simple structure in which a noise filter tape having the function of an electrostatic noise filter on one surface and the function of an electromagnetic noise filter on the other surface is provided in the cable, both the electrostatic noise and the electromagnetic noise are reduced. Can be provided at a low cost.

Further, according to the present invention, it is only necessary to wind the above-mentioned noise filter tape around the shield layer in the cable, and therefore, the present invention has an effect that it can be easily applied to existing low-grade cables. .

[Brief description of the drawings]

FIG. 1 is a partial development view of a communication cable according to the present invention.

FIG. 2 is a partially enlarged cross-sectional view of the noise filter tape according to the present invention.

FIG. 3 is a sectional view of a communication cable according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Communication cable 2 Signal line 3 Inner insulator 4 Shield layer 5 Noise filter tape 5a Plastic tape base material 5b Conductive treatment layer 5c Iron oxide treatment layer 6 External insulator

Continuation of front page (58) Fields investigated (Int.Cl. ⁷ , DB name) H01B 11/06 H01B 5/14 H01B 7/17 H05K 9/00

Claims (2)

(57) [Claims] 1. A communication cable comprising: a signal line; a shield layer provided around the signal line via an internal insulator; and an external insulator formed on the shield layer. A noise filter tape having a plastic tape as a base material, and having a function of an electrostatic noise filter on one surface and a function of an electromagnetic noise filter on the other surface between the base material and the external insulator. The communication cable is wound so that one side of the electrostatic noise filter side is electrically connected to the shield layer. 2. The method according to claim 1, wherein the electrostatic noise filter formed on one surface of the base material comprises a conductive treatment layer, and the electromagnetic noise filter formed on the other surface comprises an iron oxide treatment layer. The communication cable according to claim 1.