JP2005183271A - Flexible cable - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problems that there is no flexible cable to spuriously constitute a coaxial transmission path thereby; the cable should be forcibly bent when a connector or the like is mounted on front-back both faces of the cable, flexing resistance against bending should be reinforced and signals with different potentials cannot be transmitted in the case of presence of a plurality of conductive lines. <P>SOLUTION: A flexible cable 1 is composed of the conductive lines; conductive shield members surrounding around the lines with desired intervals; and a base made of an insulating material and supporting the lines and members. The lines are provided together at a plurality of spots, the members are surrounded by each conductive line and are not electrically connected to the members surrounding other conductive lines and independent from one another. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention is used for connection between printed circuit boards, connection between electronic components, or connection between a printed circuit board and electronic components, etc., and in particular, a flexible cable (FPC: Flexible Printed Circuit Boards), flexible This relates to antennas and the like.

  Conventionally, shielded coaxial cables are mainly used as cables used for high-speed transmission, while flexible cables are mainly used for transmission of small devices such as mobile phones.

However, even in small devices, high-speed transmission is required, and the use of shields is required because it dislikes ambient noise. Therefore, there are known flexible cables that not only have electrical circuits, but are also shielded (see Patent Document 1).
Japanese Patent Laid-Open No. 7-170089

  However, in a flexible cable having a shield, the shield structure has, for example, a common ground portion that surrounds a plurality of conductor lines, and there is no individual independent structure. Therefore, signals having different potentials cannot be transmitted to a plurality of conductor lines that transmit electrical signals.

  The problem to be solved is that there is no one that constitutes a coaxial transmission line in a pseudo manner with a flexible cable, and when a connector is mounted on both sides of the flexible cable, the cable must be bent forcibly. In addition, it is necessary to reinforce the bending resistance against bending, and furthermore, when there are a plurality of conductive lines, signals having different potentials cannot be transmitted.

  The flexible cable according to the present invention is a flexible cable comprising a conductor line, a conductive shield member surrounding the conductor line with a desired gap, and a base of an insulating material that supports them. A conductor line is provided at a plurality of locations, the shield member is surrounded by each conductor line, and the shield member is independent from each other without being electrically connected to a shield member surrounding another conductor line. is there.

Mounting portions for electrical and electronic parts are provided on the front side and the back side of the conductor line;
In addition, a reinforcing tape is attached to the bent part of the cable;
Further, the shield member includes an upper conductive member that is in an upper position in the vertical direction with respect to the conductor line, a left conductive member / right conductive member that is in the same position, a lower conductive member that is in a lower position, and the upper conductive member And a conductive connecting member electrically connecting the left and right conductive members and the lower conductive member and penetrating the base on both sides of the conductor line, the connecting member being staggered along the wiring direction of the conductor line It includes that being arranged.

  In the flexible cable of the present invention, since the shield members of the conductor lines provided side by side are electrically independent from each other, signals having different potentials can be transmitted.

In addition, since electric / electronic parts can be mounted on both sides of the conductor line, it is not necessary to bend the cable forcibly, and damage to the cable can be prevented. Furthermore, the bending resistance is improved by winding a reinforcing tape around the bent portion of the cable.
By arranging the connecting members in the shield member in a staggered arrangement along the wiring direction of the conductor lines, the influence of disturbance noise and transmission loss can be kept low.

  A flexible cable 1 according to the present invention is a flat flexible cable as shown in FIG. 1, and has a conductor line 2 and a desired gap around the conductor line 2 as shown in FIG. The conductive shield member 3 that surrounds and the base 4 of an insulating material that supports them.

  The conductor lines 2 are provided at a plurality of locations, the shield members 3 are surrounded by the conductor lines 2, and the shield members 3 are not electrically connected to the shield members 3 surrounding the other conductor lines 2. Independent of each other. Thereby, signals having different potentials can be transmitted when there are a plurality of conductive lines.

  Thus, the conductor line 2 and the shield member 3 are independent as a pseudo coaxial transmission line. When these pseudo coaxial transmission lines are stacked vertically and horizontally and viewed in plan, they can be arranged in a lattice pattern. In addition, the flexible cable 1 can be formed by using one or more of the pseudo coaxial transmission lines as a power source or a ground line for the entire apparatus, or by using both of them.

  In the cross-sectional view as shown in FIG. 2, the shield member 3 includes an upper conductive member 5 located at an upper position in the vertical direction with respect to the conductor line 2, a left conductive member 6 and a right conductive member 7 located at the same position, The lower conductive member 8 in the lower position, the upper conductive member 5, the left and right conductive members 6, 7 and the lower conductive member 8 are electrically connected to each other at a predetermined separation distance on both sides of the conductor line 2. A conductive connecting member (also referred to as a bump) 9 that penetrates the base 4 is formed. FIG. 3A shows an enlarged part of the cross-sectional view.

  As shown in FIGS. 3B and 3C, the connecting members 9 are staggered along the wiring direction of the conductor lines 2. The connecting member 9 has a via hole (also referred to as a through-hole) drilled by a laser at a place where the connecting member is disposed on a thermoplastic resin base material, filled with a metal paste, pressed in multiple layers, and spaced apart from each other. The conductive members (5, 6 or 7, 8) are formed so as to be electrically connected through the connecting member 9. By arranging the connecting members 9 in a staggered arrangement, the connecting members 9 are arranged at a high density without a gap when viewed from the orthogonal direction of the conductor lines 2, and the influence of disturbance noise and the transmission loss of the conductor lines 2 are kept low.

  In another embodiment, as shown in FIG. 4, the conductor line 2 is a flexible cable suitable for high-speed transmission of high-frequency signals as differential transmission lines 2a and 2b for flowing the same signal through a pair of transmission lines. be able to. In this case, as shown in FIGS. 4A and 4B, there are a case where they are arranged horizontally in parallel and a case where they are arranged in parallel vertically. The high-frequency signal transmission characteristic that is free from disturbance noise can be maintained with high performance by the flexible cable 1 according to the present invention.

  As shown in FIG. 5, the flexible cable 1 has a reinforcing tape 10 attached to a predetermined bent portion 1a. This reinforcing tape is, for example, a woven fabric tape. Thereby, when bending inside a small electronic device, the bending resistance which resists bending repeatedly improves.

  Further, as shown in FIG. 6, mounting portions for electrical / electronic components 11 are provided on the front side and the back side of the conductor line 2 at, for example, both ends of the flexible cable 1. The electric / electronic component 11 is, for example, a coaxial contact, an antenna, an LED, a speaker, or the like. As a result, the parts can be electrically joined without forcibly bending the flexible cable 1, thereby improving the reliability.

It is a top view of flexible cable 1 concerning the present invention. It is sectional drawing along the AA line in FIG. They are a partially expanded sectional view (A) of the flexible cable 1, a sectional view (B) showing an example in which the bumps 9 are arranged in a staggered manner, and a plan view (C). It is sectional drawing (A), (B) at the time of making the conductor line 2 into a differential transmission path. They are the side view (A) which shows a mode that the reinforcement tape 10 was stuck to the bending part 1a of the flexible cable 1 which concerns on this invention, and a top view (B). It is explanatory drawing (A), (B) explaining a mode that an electrical component etc. are mounted in the front and back of the flexible cable 1. FIG.

Explanation of symbols

1 Flexible cable,
2 conductor lines,
2a, 2b differential transmission member,
3 Shield member,
4 base,
5 Upper conductive member,
6 Left conductive member,
7 Right conductive member,
8 Lower conductive member,
9 connecting members,
10 Reinforcing tape,
11 Electrical and electronic parts.

Claims (4)

In a flexible cable comprising a conductor line, a conductive shield member surrounding the conductor line with a desired gap, and a base of an insulating material that supports them,
The conductor lines are provided at a plurality of locations, the shield members are surrounded by the conductor lines, and the shield members are not electrically connected to the shield members surrounding the other conductor lines and are independent of each other. ,
Flexible cable characterized by Mounting portions for electrical and electronic parts are provided on the front side and back side of the conductor line,
The flexible cable according to claim 1. Reinforcement tape is stuck on the bent part of the cable,
The flexible cable according to claim 1 or 2. The shield member includes an upper conductive member in an upper position in the vertical direction with respect to the conductor line, a left conductive member / right conductive member in the same position, a lower conductive member in a lower position, the upper conductive member, and the left and right conductive members. The conductive member and the lower conductive member are electrically connected to each other and a conductive connecting member penetrating the base on both sides of the conductor line. The connecting member is arranged in a staggered manner along the wiring direction of the conductor line. That
The flexible cable according to any one of claims 1 to 3.

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