JPH07131181A - Flexible cable - Google Patents

Abstract

PURPOSE:To make it possible to shield electrical noise, which is produced by a signal conductor to the outside, or external electrical noise, which inflicts an adverse effect on the signal conductor, by a method Wherein the same shielding effect as that obtainable by wrapping the signal conductor in a metal tube is obtained by bringing into contact electrically fellow earth patterns to each other. CONSTITUTION:A signal pattern 101 is formed on the inner side of a substrate, earth patterns 102 are formed on the outer side of the substrate, the substrate is folded into two, the patterns 102 are arranged in such a way as to wrap the pattern 101 therein and moreover, fellow both ends of the approached patterns 102 are electrically brought into contact to each other.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flexible cable for transmitting electric signals used inside or outside a housing of an electronic device such as a computer.

[0002]

2. Description of the Related Art In recent years, due to the high performance of CPUs, high density mounting of boards, increase of memory capacity, downsizing of disk devices and downsizing of display devices typified by liquid crystals, they have been used for personal purposes. The spread of compact computers that can be done is remarkable. With such a trend toward miniaturization, a thin sheet-like flexible cable has been widely used as a cable for electrically connecting the respective parts in the electronic device housing, compared with the conventional flat cable. On the other hand, on the other hand, the speed of electric signals has been increasing, and along with this, the cables through which high speed signals are transmitted have become more likely to generate electrical noise and to be affected by electrical noise from the outside. Therefore, various measures have been taken when using a flexible cable in an electronic device that is becoming more compact. An example of the configuration of the above-described conventional flexible cable will be described below with reference to the drawings.

FIG. 13 is a perspective view showing a conventional flexible cable shielding method, and FIG. 14 is a perspective view showing a schematic configuration of the conventional flexible cable shielding method.

In FIGS. 13 and 14, 1301 is a flexible cable for transmitting electric signals and 1302 is a copper tape coated with an adhesive. In the conventional flexible cable thus configured, the shielding effect is generated by attaching the copper tape 1302 to the signal pattern surface of the flexible cable 1301.

[0005]

However, in the above-mentioned structure, since the copper tape 1302 must be attached to the flexible cable 1301, the number of working steps is increased, and the member cost and the manufacturing cost are increased. Was there. Furthermore, the copper tape 1302 may change the flexible cable 13 due to defective work or aging.
There is also a problem that it is difficult to maintain a constant shield effect by separating the foil from No. 02.

In view of the above problems of the conventional flexible cable, the present invention provides a flexible cable which is stable, low-priced and highly reliable by providing the flexible cable itself with a shielding effect.

[0007]

A flexible cable of the present invention comprises a folded board, a signal pattern formed inside the board, and a ground pattern formed outside the board. Is in a state of enclosing the signal pattern.

The flexible cable of the present invention is
An opening is opened in a part of the portion that hits the center line of the fold.

Further, the flexible cable of the present invention is
Due to the bending, the adjacent ground patterns are brought into electrical contact with each other.

Further, the flexible cable of the present invention is
A part of the earth pattern can be electrically connected to the earth part of an electronic device using a flexible cable.

[0011]

In the flexible cable of the present invention, the ground pattern wraps around the signal pattern with the above-mentioned structure, so that the shield effect is generated.

Further, the bending work can be simplified by providing an opening in the bending portion.

By further bending and bringing the adjacent earth patterns into contact with each other, the earth pattern becomes completely tubular and a higher shielding effect is generated.

Further, a more stable shield effect is generated by connecting the ground portion of the electronic equipment casing using the flexible cable and the ground pattern of the flexible cable.

[0015]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a perspective view showing the appearance of a flexible cable having one signal layer and one ground layer of a flexible cable according to an embodiment of the present invention, and FIG. 2 shows the flexible cable of FIG. 1 as a signal layer. Development view from the side, Fig. 3
FIG. 2 is a development view of the flexible cable of FIG. 1 viewed from the ground layer side. In FIG. 1, 101 is a signal pattern formed on the inner signal layer, and 102 is an earth pattern formed on the outer earth layer. In FIG. 2, 101 is a signal pattern, and in FIG. 3, 102 is a ground pattern.
Is formed on the outside according to the outer shape of the flexible cable. In this embodiment, the signal layer and the ground layer mainly constitute the substrate, and as is clear from FIG. 1, they are bent and folded in two. That is, by bending a part of the flexible cable so that the signal pattern 101 is wrapped with the ground pattern 102 as shown in FIG. 1, it is possible to prevent noise generated from the signal pattern from leaking to the outside. Conversely, it is possible to prevent external noise from acting on the cable. In the present embodiment shown in FIG. 1, the bent portion of the flexible cable in the horizontal direction is not wrapped with the ground pattern 102, but the bent portion may also be wrapped by changing the shape of the ground pattern 102 such as partially extending it. Good.

Next, FIG. 4 is a perspective view showing the appearance of a flexible cable having an opening at the bent portion, and FIG. 5 is shown in FIG.
4 is a development view of the flexible cable of FIG. 6 viewed from the signal layer side, and FIG. 6 is a development view of the flexible cable of FIG. 4 viewed from the ground layer side. In FIG. 4, 401 is a signal pattern formed on the signal layer, 402 is an earth pattern formed on the earth layer, and 403 is an opening formed along the center line of the bent portion. Moreover, in FIG.
1 is a signal pattern, 403 is an opening, and in FIG.
Reference numeral 02 is a ground pattern, and 403 is an opening. When the flexible cable configured as described above is wrapped around the signal pattern 401 with the ground pattern 402 as shown in FIG. 4, it can be bent around the opening 403, so that the bent portion is accurate and the reliability of the work is increased. To do.

Next, FIG. 7 is a perspective view showing the appearance of a flexible cable in which adjacent ground layers are brought into contact with each other by bending, FIG. 8 is a partial sectional view of the flexible cable in FIG. 7, and FIG. 9 is a flexible view in FIG. FIG. 10 is a development view of the cable viewed from the signal layer side, and FIG. 10 is a development view of the flexible cable in FIG. 7 viewed from the ground layer side. In FIG. 7, 7
Reference numeral 01 is a signal pattern formed on the signal layer, and 702 is an earth pattern formed on the earth layer. In FIG. 10, reference numeral 702 is a ground pattern formed on a ground layer, 1002 is terminal portions A, 1003, 1004, 1 which are electrical contacts made at the end of the ground pattern 1001.
Reference numerals 005 denote a terminal portion B, a terminal portion C, and a terminal portion D, respectively, which are the same as 1002. The flexible cable configured as described above is partially bent so as to wrap the signal pattern 701 with the ground pattern 702 as shown in FIG. 7, and further, as shown in A part of FIG. 8, the terminal portion A1002 and the terminal portion B1003 are connected. Contact, and similarly terminal portion C10
When 04 and the terminal portion D1005 are brought into contact with each other, a shielding effect against electric noise similar to that of wrapping the signal pattern 701 with a copper tube is exhibited. In addition, in the embodiment of FIG. 7, as shown in FIG. 8, the adjacent ground layer portions are further folded back to make contact with each other. By connecting to 702 with a through hole, the ground patterns of the signal layer may be brought into contact with each other without folding back the ground layer portion. In addition, 703 of FIG. 8 is an insulating coating.

Next, FIG. 11 is a perspective view showing a state in which a part of the ground layer of the flexible cable and the ground portion of the electronic device are connected, and FIG. 12 is a development view of the flexible cable of FIG. 11 viewed from the ground layer. Is. In FIG. 11, 1
101 is a signal pattern configured on the signal layer, 1102
Is a ground pattern formed on the ground layer, 1103 is a terminal part E connected to the ground part of the electronic device, 1104 is a similar terminal part F, 1105 is a ground part of the electronic device, 110
Reference numeral 6 is a fixing screw for connecting and fixing the flexible cable and the ground portion 1105. In addition, in FIG.
01 is a screw hole through which the fixing screw passes.

As shown in FIG. 11, the flexible cable configured as described above is partially bent so as to wrap the signal pattern 1101 with the earth pattern 1102,
Further, by fixing the terminal portion E1103 and the terminal portion F1104 to the ground portion 1105 of the electronic device with the fixing screw 1106 and electrically connecting them, the ground level is stabilized and a more effective shield effect is exhibited. . In addition, in the embodiment of FIG. 11, the fixing to the ground portion of the electronic device is performed by the screw, but the outer coating of the ground pattern 1102 may be eliminated to make the surface contact with the ground portion 1105.

In this embodiment, the flexible cable is L-shaped, but it goes without saying that it may have any other desired shape.

[0022]

As is apparent from the above description,
In the flexible cable of the present invention, when the ground pattern wraps around the signal pattern, the electrical noise generated from the signal pattern leaks to the outside, and the electrical noise from the outside affects the signal pattern. It is possible to prevent it without using additional members such as aluminum tape.

Further, the number of assembling steps of electronic equipment can be reduced.

Further, by providing an opening at the bent portion of the flexible cable, the bending work can be simplified, and a highly reliable shield effect can be exhibited.

Further, by bending and electrically contacting the adjacent ground patterns with each other, a shielding effect similar to that of wrapping a signal line with a metal tube can be realized.

Further, by bringing the earth pattern into contact with the earth part of the electronic device, a more stable shield effect can be exhibited.

[Brief description of drawings]

FIG. 1 is a perspective view showing an appearance of a flexible cable according to an embodiment of the present invention.

FIG. 2 is a development view of the flexible cable in the same embodiment as seen from its signal layer side.

FIG. 3 is a development view of the flexible cable in the same embodiment as seen from its ground layer side.

FIG. 4 is a perspective view showing the outer appearance of a flexible cable according to another embodiment of the present invention.

FIG. 5 is a development view of the flexible cable in the same embodiment as seen from its signal layer side.

FIG. 6 is a development view of the flexible cable in the same embodiment as seen from its ground layer side.

FIG. 7 is a perspective view showing the outer appearance of a flexible cable according to another embodiment of the present invention.

FIG. 8 is a partial cross-sectional view of the flexible cable in the same example.

FIG. 9 is a development view of the flexible cable in the same embodiment as seen from its signal layer side.

FIG. 10 is a development view of the flexible cable in the same embodiment as seen from its ground layer side.

FIG. 11 is a perspective view showing a connection between a flexible cable and an electronic device according to another embodiment of the present invention.

FIG. 12 is a development view of the flexible cable in the same embodiment as seen from the ground layer side thereof.

FIG. 13 is a perspective view showing a conventional method of shielding a flexible cable.

FIG. 14 is a perspective view showing a schematic configuration of a conventional flexible cable shielding method.

[Explanation of symbols]

10 board 1003 terminal part B 101 signal pattern 1004 terminal part C 102 earth pattern 1005 terminal part D 401 signal pattern 1101 signal pattern 402 earth pattern 1102 earth pattern 403 opening 1103 terminal part E 701 signal pattern 1104 terminal part F 702 earth pattern 1105 Ground part 1002 Terminal part A 1106 Fixing screw

Claims (4)

[Claims] 1. A folded board, a signal pattern formed on the inside of the board, and a ground pattern formed on the outside of the board, wherein the ground pattern surrounds the signal pattern. A flexible cable that is characterized by 2. The flexible cable according to claim 1, wherein an opening is formed in a part of a portion of the folded substrate that is in contact with the center line of the bent portion. 3. Both ends of the ground pattern are formed on the outside of the folded substrate so as to be close to each other, and the both ends close to each other are in electrical contact with each other. The flexible cable according to claim 1 or 2. 4. A part of the ground pattern is configured to be electrically connectable to a ground part of an electronic device using the flexible cable.
The flexible cable described in 2 or 3.