JP2007095435A - Flexible flat cable and jumper member used for it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a flexible flat cable of which a shield tape is easily grounded for improved performance and reliability. <P>SOLUTION: A cable body 2 consists of a plurality of conductors 10 and first and second insulating films 20 and 30 for covering the conductors 10. A shield tape 40 is wound round the first and second insulating films 20 and 30. The minus side of a ground electrode 50 is inserted between the first insulating film 20 and the shield tape 40. The other side of the ground electrode 50 is extended outside from the cable body 2, for electrical connection to the ground. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a flexible flat cable and a jumper member used therefor.

  Conventionally, a flexible flat cable (hereinafter referred to as FFC) is space-saving in AV equipment such as a VTR, CD, DVD player, OA equipment such as a copying machine, a scanner, and a printer, and other electronic equipment, and simplified between printed boards. For the purpose of easy connection, it is used to connect printed circuit boards built in these electric devices. Further, from the viewpoint of noise prevention, a metal shield tape is often wound around the FFC so as to cover an insulating film that covers a plurality of conductors of the FFC from the outside (for example, Patent Document 1). reference).

In this type of prior art, in order to drop the shield tape to the ground, for example, the insulating film interposed between the FFC shield tape and the ground conductor is peeled to expose the ground conductor, The shield tape is dropped to the ground by making contact with the shield tape.
Japanese Patent Laid-Open No. 2002-352631

  By the way, in the prior art, when the FFC conductor is connected to the connector of the printed circuit board, the end of the conductor is plated with lead and the end of the conductor is connected to the connector. However, in recent years, a method of applying gold plating to the end portion of the conductor has been studied from the viewpoint of measures against whiskers.

  However, when gold plating is applied to the conductor in this way, for the convenience of plating processing, as described above, it is impossible to perform processing that peels off the insulating film interposed between the shield tape and the ground conductor. There is.

  The present invention has been made in view of such problems, and provides a flexible flat cable and a jumper member used therefor, in which a shield tape can be easily dropped to the ground and performance, reliability, and the like can be improved. There is.

  The present invention for solving the problems of the prior art is a flexible flat cable, in which a plurality of conductors arranged so as to extend substantially parallel to each other are covered with an insulating film, and the insulating film A shield tape made of a conductive material wound around the outside of the cable, and a jumper member having one side electrically connected to the shield tape and the other side extending outside the cable body and connected to the ground. It is characterized by being composed.

  According to the flexible flat cable of the present invention, the jumper member that is electrically connected to the shield tape extends from the cable body and is connected to the ground, so that the shield tape can be easily dropped to the ground by the jumper member. It is possible to improve the performance and reliability of the flexible flat cable.

  Embodiments of the present invention will be described with reference to the drawings. A flexible flat cable 1 (hereinafter referred to as FFC 1) according to an embodiment of the present invention includes a cable body 2, a shield tape 40, and a jumper member 50 as shown in FIGS. The cable body 2 of the FFC 1 is composed of a plurality of conductors 10, 10,..., A first insulating film 20 and a second insulating film 30.

  The conductors 10, 10,... Are formed as thin, thin and substantially rectangular flat plates using a conductive material. These conductors 10 are arranged so as to extend substantially in parallel with each other at substantially equal intervals in the width direction. Both end portions 10A and 10B of the conductor 10 are connected to connectors 100A and 101A (see FIG. 1) of the printed circuit boards 100 and 101 incorporated in the electronic device, for example. In addition, gold plating instead of the lead plating described in the prior art is used for contact portions (electrodes) of the both ends 10A and 10B of the conductor 10 which are connected in surface contact with the connectors 100A and 101A. It has been subjected.

  The first and second insulating films 20 and 30 are formed as films having a substantially rectangular shape using an insulating material such as a resin material, for example, and are overlapped with each other with the conductors 10 interposed therebetween. And the contact site | part of the 1st insulating film 20 and the 2nd insulating film 30, the contact site | part of the 1st insulating film 20 and each conductor 10, and the contact site | part of the 2nd insulating film 30 and each conductor 10 are as follows. It is bonded using an insulating adhesive or the like. Further, as shown in FIG. 1, the first insulating film 20 is formed shorter than the second insulating film 30. As a result, both end portions 10A and 10B on which the gold plating is applied in the conductor 10 are exposed to the outside.

  The shield tape 40 is formed as a tape made of a metal material such as aluminum. The shield tape 40 is covered (wrapped) over the entire surface of the first and second insulating films 20 and 30 except for both ends in the length direction. The shield tape 40 is attached to the first and second insulating films 20 and 30 and a mounting plate portion 50B of a jumper member 50 described later by, for example, heat sealing.

  The jumper member 50 is formed as shown in FIG. 5 using a conductive plate material such as a copper plate. The jumper member 50 has a substantially rectangular main body plate portion 50A, a substantially rectangular attachment plate portion 50B integrally formed on one side of the main body plate portion 50A, and the other side of the main body plate portion 50B. And a bent plate portion 50C that is bent and extended in a substantially L shape. The jumper member 50 is attached with the mounting plate portion 50B inserted between the first insulating film 20 and the shield tape 40. Further, the mounting plate portion 50B of the jumper member 50 is bonded to the first insulating film 20 on the back side with a double-sided tape. Further, the surface side of the mounting plate portion 50B is integrally attached to the shield tape 40 by heat fusion.

  As shown in FIG. 1, the jumper member 50 has the other side (end portion side) of the main body plate portion 50 </ b> A extending outward from the cable body 2 in the width direction. 2 projecting in the length direction. In the jumper member 50, the protruding end side of the bent plate portion 50C is electrically connected to the ground region of the printed circuit board 100, and the shield tape 40 falls to the ground. In other words, the jumper member 50 determines the ground potential of the shield tape 40. In addition, as shown by a broken line in FIG. 5, in jumper member 50, the entire surface of main body plate portion 50 </ b> A and the entire base plate side of bent plate portion 50 </ b> C are covered with an insulating film.

  As described above, the FFC 1 according to the present embodiment extends (projects) the jumper member 50 electrically connected to the shield tape 40 from the cable body 2 and connects the projecting end side to the ground. Accordingly, the shield tape 40 is dropped to the ground. For this reason, the shield tape 40 can block external noise from being mixed into the transmission signal transmitted through each conductor 10 or leakage of noise accompanying the transmission signal to the outside.

  Therefore, even when the conductor 10 of the FFC 1 is plated with gold, the insulating film 20 interposed between the shield tape 40 and the ground conductor 10 is peeled off as in the prior art in order to drop the shield tape 40 to the ground. Such a process can be made unnecessary, the shield tape 40 can be easily dropped to the ground by the jumper member 50, and the performance and reliability of the FFC 1 can be improved.

  In the present embodiment, the case where the substantially L-shaped jumper member 50 is used has been described as an example. However, the present invention is not limited to this, and for example, a jumper member 60 that extends straight may be used as in the modification shown in FIGS. 6 and 7.

  Here, like the jumper member 50, the jumper member 60 is formed using a conductive plate material such as a copper plate. The jumper member 60 includes a main body plate portion 60A that is elongated in a substantially rectangular shape, and a substantially rectangular attachment plate portion 60B that is integrally formed on one side of the main body plate portion 60A. The jumper member 60 is attached with the mounting plate portion 60 </ b> B inserted between the first insulating film 20 and the shield tape 40. Further, the mounting plate portion 50B of the jumper member 50 is bonded to the first insulating film 20 on the back side with a double-sided tape. Further, the surface side of the mounting plate portion 50B is integrally attached to the shield tape 40 by heat fusion.

As shown in FIG. 6, the jumper member 60 has the other side (end side) of the main body plate portion 60 </ b> A protruding in the width direction from the cable body 2, and a circular screw retaining hole 60 </ b> C is formed on the protruding end side. It has been drilled. The jumper member 60 is such that the protruding end side of the main body plate portion 60A protruding from the cable main body 2 is electrically connected to the ground region of the printed circuit board 101 through the screw fixing hole 60C, and the shield tape 40 is dropped to the ground. Yes. Note that the entire surface of the main body plate portion 60A of the jumper member 60 excluding the peripheral edge of the screw retaining hole 60C is covered with an insulating film as shown by a broken line in FIG.

It is a top view which shows FFC which concerns on embodiment of this invention. It is sectional drawing which looked at FFC from the arrow II-II direction in FIG. It is sectional drawing which looked at FFC from the arrow III-III direction in FIG. It is sectional drawing which looked at FFC from the arrow IV-IV direction in FIG. It is a top view which shows the jumper member in FIG. It is a top view which shows FFC by the modification of this invention. It is a top view which shows the jumper member in FIG. 6 alone.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Flexible flat cable (FFC), 2 Cable main body, 10 Conductor, 20 1st insulating film, 30 2nd insulating film, 40 Shield tape, 50, 60 Jumper member, 100A, 101A connector.

Claims (6)

A cable body in which a plurality of conductors arranged so as to extend substantially parallel to each other are covered with an insulating film;
A shield tape made of a conductive material wound around the outside of the insulating film;
A jumper member having one side electrically connected to the shield tape and the other side extending out of the cable body and connected to the ground;
A flexible flat cable comprising a cable.   The flexible flat cable according to claim 1, wherein a gold plating is applied to a connection portion of the cable main body with the connector of the conductor.   The jumper member protrudes in the width direction of the cable body, is further bent in an approximately L shape from there and is formed to protrude in the length direction of the cable body, and the protruding end side is connected to the ground. The flexible flat cable according to claim 1.   The flexible flat cable according to claim 1, wherein the jumper member protrudes in the width direction of the cable body, and the protruding end side is connected to the ground by screwing.   The flexible flat cable according to claim 1, 2, 3, or 4, wherein the jumper member is attached in a state where one side thereof is inserted between the insulating film and the shield tape. A cable body in which conductors extending substantially parallel to each other are covered with an insulating film;
A shield tape wound around the insulating film;
Used with flexible flat cables including
One side electrically connected to the shield tape;
Conducting to the one side, extending outside the flexible flat cable and electrically connected to the ground of the conductor;
A jumper member for use in a flexible flat cable that defines the ground potential of the shield tape.

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