JP2010177517A - Cable for transmitting electric signal - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cable for transmitting electric signals, which reduces radiation noise without increasing time required for manufacture and manufacturing costs to allow good signal transmission. <P>SOLUTION: The cable for transmitting the electric signals is provided with: a plurality of wiring 3, 5; connection parts 1A, 1B provided at both ends in a direction where the plurality of wiring 3, 5 extend; and a conductive member 4 which covers the plurality of wiring 3, 5. The plurality of wiring 3, 5 are provided with: a first wiring 3 covered by an insulating material; and a second wiring 5 at least a part of which is not covered, the conductive material 4 is electrically connected to an area uncovered of the second wiring 5, and ground potential is supplied to the second wiring 5. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to an electric signal transmission cable.

  With the recent increase in speed and performance of electronic devices, the effects of radiation noise from electronic devices on other electronic devices have become a problem. The influence of this radiation noise on other electronic devices is called EMI (Electro Magnetic Interference) and causes malfunction of the electronic devices.

  Radiation noise from electronic devices is generated from printed circuit boards and cables connected between printed circuit boards. In particular, cables that are connected to transmit electrical signals between printed circuit boards have become increasingly problematic as radiation sources of radiation noise due to the recent increase in transmission signal speed, and how to suppress radiation noise from cables. It is a problem whether to do.

  Conventionally, as a technique for suppressing radiation noise from a cable, a space in which a cable for transmitting and receiving an electrical signal by electrically connecting two printed circuit boards is sandwiched between conductive members having substantially the same potential as the ground A technique for reducing radiation noise from a cable has been proposed (see Patent Document 1).

JP 2004-128205 A

  However, in the above prior art, the conductive member having substantially the same potential as the ground is fixed by screwing to the shield box, the number of parts other than the cable is increased, and special processing is required, which is necessary for manufacturing. In some cases, the time and manufacturing cost were increased.

  The present invention has been made in view of the above circumstances, and provides an electric signal transmission cable capable of reducing radiation noise and enabling good signal transmission without increasing the time and manufacturing cost required for manufacturing. The purpose is to do.

  An electric signal transmission cable according to an aspect of the present invention includes a plurality of wirings, connection portions provided at both ends in a direction in which the plurality of wirings extend, and a conductive member that covers the plurality of wirings. The wiring includes a first wiring covered with an insulating material, and a second wiring that is not at least partially covered, and the conductive member is electrically connected to an uncovered region of the second wiring. The second wiring is an electric signal transmission cable which is a wiring to which a ground potential is supplied.

  According to the present invention, it is possible to provide an electrical signal transmission cable that can reduce radiation noise and increase signal transmission without increasing the time and manufacturing cost required for manufacturing.

It is a figure for demonstrating one structural example of the cable for electrical signal transmission which concerns on one Embodiment of this invention. It is a figure for demonstrating one structural example of the cable for electrical signal transmission which concerns on a comparative example.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. As shown in FIG. 1, the electric signal transmission cable according to the present embodiment includes a cable 2 having a plurality of wirings and connectors (connection portions) 1A and 1B provided at both ends of the cable 2.

  The connectors 1A and 1B are connected to, for example, a circuit board, and an electric signal is transmitted and received between the circuit boards via an electric signal transmission cable. The cable 2 includes a wiring (first wiring) 3 covered with an insulating material and a wiring (second wiring) 5 not covered with an insulating material. The wiring 3 is a twin-pair cable, for example. The wiring 5 is a bare wire disposed at both ends of the cable 2 in a direction substantially orthogonal to the direction in which the cable 2 extends.

  The periphery of the cable 2 is covered with the conductive member 4 so that the wiring 5 and the conductive member 4 are electrically connected. In the electric signal transmission cable according to the present embodiment, the conductive member 4 is a conductive tape. Since the conductive tape is electrically connected to the wiring 5, the conductive tape becomes conductive with the wiring 5.

  As described above, by arranging the wiring 5 as a bare wire and arranging it at the end in the direction substantially orthogonal to the direction in which the cable 2 extends, the area that can come into contact with the conductive member 4 can be increased, and the conductive material can be reliably conductive. The member 4 and the wiring 5 can be set to the same potential.

  Here, when the ground potential is supplied to the wiring 5, the conductive member 4 also becomes the ground potential. Therefore, the periphery of the cable 2 is covered with the conductive member 4 having the ground potential. As described above, a part of the wiring of the cable 2 is a bare wire that is not covered with an insulating material, and a ground potential is supplied to the bare wire so that special parts are used or the cable 2 is specially processed. The ground potential can be supplied to the conductive member 4 that covers the periphery of the cable 2. By covering the cable 2 with the conductive member 4 to which the ground potential is supplied, the influence of radiation noise from the cable 2 can be reduced.

  FIG. 2 shows an electric signal transmission cable according to a comparative example. In the following description, components similar to those of the electric signal transmission cable shown in FIG.

  As shown in FIG. 2, the electric signal transmission cable according to the comparative example includes a cable 2 and connectors 1 </ b> A and 1 </ b> B provided at both ends of the cable 2. The cable 2 includes a plurality of wirings 3. The wiring 3 is covered with an insulating material. That is, the electric signal transmission cable according to the comparative example does not include the wiring 5 that is a bare wire. In the electric signal transmission cable according to the comparative example, in the direction substantially orthogonal to the direction in which the cable 2 extends, the wires arranged at both ends of the cable 2 are not bare wires but wires 3 covered with an insulating material. The ground potential is supplied to the coated wiring 3.

  The periphery of the cable 2 is covered with a conductive member 4. The cable 2 is further fixed from above the conductive member 4 by a conductive fixing member 7. The conductive fixing member 7 is electrically connected to the external ground 6. Accordingly, the ground potential is supplied to the conductive member 4 from the external ground 6 via the conductive fixing member 7.

  As shown in FIG. 2, when a ground potential is supplied to the conductive member 4, the number of parts increases and the manufacturing cost increases, and the conductive fixing member 7 is connected to the external ground 6 and the conductive member 4. It is necessary to fix so as to be electrically connected to each other, and the time required for manufacturing increases.

  On the other hand, in the electric signal transmission cable according to the present embodiment, the cable 2 having the bare wire as the wiring 5 is covered with the conductive member 4 and the ground potential is supplied to the wiring 5 only. It is possible to cover with the conductive member 4. Moreover, by using a conductive tape as the conductive member 4, the cable 2 can be covered with the conductive member 4 by sticking the conductive tape around the cable 2, which is easy.

  That is, the electrical signal transmission cable according to the present embodiment provides an electrical signal transmission cable that reduces radiation noise and enables good signal transmission without increasing manufacturing time and manufacturing cost. be able to.

  For example, when the electrical signal transmission cable according to the present embodiment is mounted on a device that uses a differential small amplitude signal, the differential small amplitude signal has a small amplitude and thus is easily affected by noise, and there is a problem in reducing radiation noise. It may become.

  In addition, when a differential small amplitude signal is supplied to the cable, the frequency of the transmission signal is increased by high-speed transmission, so that reduction of radiation noise may be a problem. In order to solve such a problem, by using the electric signal transmission cable according to the present embodiment, it is possible to reduce radiation noise by a simple method as described above and realize good signal transmission. Become.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage.

  For example, the cable 2 of the electric signal transmission cable according to the above embodiment is covered with the conductive tape as the conductive member 4, but the conductive member 4 is not limited to the conductive tape, and a cable such as a foil of a conductive material. Any conductive member that can cover 2 may be used.

  Moreover, although the wiring 5 of the electric signal transmission cable according to the above embodiment is a bare wire, it is sufficient that the wiring 5 is at least partly uncoated, and the uncoated part is a conductive member. If it is electrically connected to 4, the same effect as the electric signal transmission cable according to the above embodiment can be obtained.

  Furthermore, the wiring 5 does not need to be disposed at both ends of the electric signal transmission cable, and may be disposed at one end or between the wirings 3. In any case, as long as the uncovered portion of the wiring 5 is electrically connected to the conductive member 4, the same effect as the electric signal transmission cable according to the above embodiment can be obtained.

  Further, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, you may combine the component covering different embodiment suitably.

  1A. DESCRIPTION OF SYMBOLS 1B ... Connector (connection part), 3 ... Wiring (1st wiring), 4 ... Conductive member, 5 ... Wiring (2nd wiring).

Claims (4)

Multiple wires,
Connection portions provided at both ends in the extending direction of the plurality of wirings;
A conductive member covering the plurality of wirings,
The plurality of wirings includes a first wiring covered with an insulating material, and a second wiring not covered at least in part.
The conductive member is an electric signal transmission cable which is electrically connected to an uncovered region of the second wiring, and the second wiring is a wiring to which a ground potential is supplied.   The electric signal transmission cable according to claim 1, wherein the second wiring is disposed at both ends in a direction substantially orthogonal to a direction in which the plurality of wirings extend.   The electric signal transmission cable according to claim 1, wherein the second wiring is a bare wire.   The electric signal transmission cable according to any one of claims 1 to 3, wherein the transmitted signal is a differential small amplitude signal.

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