JPH0548222A - Flexible printed-wiring board - Google Patents

Abstract

PURPOSE:To provide a flexible printed-wiring board which prevents cross talk and enables an electronic equipment to be packaged highly densely. CONSTITUTION:A signal line 3 and a ground wire 4 are alternately placed between two insulation layers 1 and 5 and they are electrically connected to one connection terminal 41 by a connection means 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flexible printed wiring board.

[0002]

2. Description of the Related Art In recent years, high density mounting of electronic parts in electronic equipment has been attempted, and a flexible printed wiring board which occupies a small space has been proposed as one of the technologies therefor. A flexible printed wiring board is one in which a conductor circuit and a signal line are formed on a flexible insulating layer, but in order to prevent crosstalk between the signal lines, avoid parallel wiring of the signal lines. A large distance between them is taken, or the signal line and the ground line are alternately arranged to form a connection terminal as they are.

[0003]

However, even if any of the above-mentioned signal line arranging methods is used, there is a problem in that the connecting terminal portion becomes large and it is difficult to achieve sufficient miniaturization.
The present invention has been made in view of the above problems, and provides a flexible printed wiring board that can prevent crosstalk, and in particular realizes miniaturization of a connecting terminal portion to occupy a small space. With the goal.

[0004]

In a flexible printed wiring board according to the present invention for solving the above problems, a plurality of signal lines and ground lines are arranged in parallel and alternately in an insulating layer having flexibility. And a plurality of connection terminals for connection are provided, and connection means for electrically connecting all the ground wires to a predetermined single connection terminal of the plurality of connection terminals is provided. It is characterized by

[0005]

In the flexible printed wiring board described above, the ground lines alternately arranged with the signal lines can prevent crosstalk between the signal lines. Further, since the signal line and the ground line are arranged in parallel, the distance between the signal lines can be narrowed. Further, since all the ground wires are electrically connected to the single connection terminal by the connecting means, only one connection terminal for the ground wire is required.

[0006]

The present invention will be described in more detail based on the following examples. FIG. 1 is a perspective view showing an embodiment of a flexible printed wiring board A according to the present invention, and FIG.
-II line sectional drawing, FIG. 3 is the III-III sectional view taken on the line.

In this flexible printed wiring board A, a plurality of signal lines 3 and ground lines 4 and 40 are bonded in parallel and alternately on an insulating layer 1 via an adhesive layer 2a. In addition, on the signal line 3 and the ground lines 4 and 40,
The second insulating layer 5 is laminated via the adhesive layer 2b.
Further, at one end of the flexible printed wiring board A, as shown in FIG. 3, one ground wire 40 is left and the other ground wire 4 is not extended, and the plurality of signal wires 3 and one The ground line 40 is made slightly thicker to form a plurality of signal line connection terminals 31 and a single ground line connection terminal 41, and a connection portion 80 for connecting to another circuit is configured. Further, on the lower surface of the connecting portion 80, the reinforcing material 8
Are glued together.

Further, as shown in FIG. 2, all the ground wires 4 and 40 are electrically connected by the connecting means 6. Further, a part of the connecting means 6 is exposed on the surface of the second insulating layer 5, and in order to cover the exposed portion,
The cover member 6 is laminated on the second insulating layer 5. In this flexible printed wiring board A, since the ground lines 4 and 40 are arranged between the signal lines 3, it is possible to prevent the crosstalk between the signal lines 3 and reduce the distance between the signal lines 3. You can

Also, this flexible printed wiring board A
In the connection portion 80 of, in addition to the signal line connection terminal 31,
Since only one ground wire connecting terminal 41 is provided, the connecting portion 80 can be downsized. The insulating layer 1 and the second insulating layer 5 should be formed of a conventionally known flexible material such as polyester, polyimide, glass epoxy, glass Teflon, polyamideimide, or polyvinyl chloride. You can

The adhesive layers 2a and 2b may be formed of an epoxy-based, urethane-based, polyester-based, or polydialkylsiloxane such as polydimethylsiloxane, polydiethylsiloxane, polymethylethylsiloxane, or a conventionally known adhesive such as polyacrylonitrile. Good.
The signal line 3, the ground line 4 and the connecting means 6 are copper,
It may be formed of silver, nickel, aluminum, or a composite system of these metals. In addition, the thickness of the signal line 3 and the ground lines 4 and 40 is usually preferably in the range of 18 to 75 μm. Signal line 3 and ground line 4, 40
As a method of forming, the so-called subtractive method of removing unnecessary portions of the thin film made of the metal material laminated on the surface of the insulating layer 1, the signal line 3 and the ground lines 4 and 40 on the surface of the insulating layer 1 are necessary. It is possible to apply a conventionally known method such as an additive method of depositing a metal material only on a portion or a semi-structive method in which a subtractive method and an additive method are combined.

The flexible printed wiring board according to the present invention is not limited to the above embodiment. For example,
A shield layer 9 may be formed on the outer surfaces of the insulating layer 1 and the second insulating layer 5 to enhance the electromagnetic shielding property. Concrete Example 1 and Comparative Example 1 A flexible printed wiring board having ten signal lines and an earth line arranged between the signal lines was arranged at a pitch of 1.25 m.
When connecting to another board through the connector of FIG.
When the flexible printed wiring board having the structure shown in (1) is used (Specific Example 1), it has 10 signal lines, the ground line is arranged between the signal lines, and The size of the connection part and the usable connector were compared in the case of using a conventional flexible printed wiring board having connection ends provided on each (Comparative Example 1).

The results are shown in Table 1.

[0013]

[Table 1]

From Table 1, it can be seen that when the flexible printed wiring board according to the present invention is connected to another substrate, a small connector having a small number of pins can be used. Specific Example 2 and Comparative Example 2 Using the flexible printed wiring board according to the present invention used in Specific Example 1 (Specific Example 2) and the conventional flexible printed wiring board used in Comparative Example 1 (Comparative Example 2), other Solder directly to terminals with a pitch of 1.5 mm on the board,
The two were compared for the formed connection part.

The results are shown in Table 2.

[0016]

[Table 2]

From Table 2, it can be seen that the connecting portion formed in the second specific example has a smaller number of terminals and a narrower width than the connecting portion of the second comparative example.

[0018]

As described above, according to the flexible printed wiring board of the present invention, since the signal lines and the ground lines are arranged in parallel and alternately, the signal lines are narrowed while the signal lines are narrowed. Crosstalk can be prevented.
Further, since all the ground wires are electrically connected to a single connecting terminal by the connecting means, the connecting portion can be made smaller and the occupied space can be made smaller. Is possible.

[Brief description of drawings]

FIG. 1 is an explanatory view showing an embodiment of a flexible printed wiring board according to the present invention.

FIG. 2 is a sectional view taken along line II-II in FIG.

3 is a sectional view taken along the line III-III in FIG.

[Explanation of symbols]

 1,5 Insulating layers 2a, 2b Adhesive layer 3 Signal line 4,40 Ground line 31 Connection terminal for signal line 41 Connection terminal for ground line A Flexible printed wiring board

Claims (1)

[Claims] 1. A plurality of signal lines and ground lines are arranged in parallel and alternately in a flexible insulating layer, and a plurality of connection terminals for connection are provided. A flexible printed wiring board is provided with a connecting means for electrically connecting to a predetermined single connecting terminal of a plurality of connecting terminals.