JPH06103825A - Flexible wiring sheet - Google Patents

Abstract

PURPOSE:To provide a flexible wiring sheet provided with a structure suppressing the radiation of electromagnetic interference EMI noise. CONSTITUTION:A plurality of conductors 13a-13d are formed on one side of a flexible long sheet 12 arid a sheet lacking part 12a is formed in at least a part of an area between the conductors 13a-13d. In the area where the sheet lacking part 12a is formed, a magnetic material-containing resin layer 14 is so formed as to cover the surrounding of the plularity of the conductors 13a-13d and to fill the sheet lacking part 12a with the resin.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flexible wiring sheet having a plurality of conductors supported by a flexible long sheet, and more particularly to a structure for removing electromagnetic interference noise (EMI noise). And a flexible wiring sheet provided with.

[0002]

2. Description of the Related Art Conventionally, in various electronic equipment such as office automation equipment, flexible wiring sheets have been widely used for the inside of the equipment and the interface between the equipment. 5 (a) and 5 (b)
[Fig. 3] is a plan view and a cross-sectional view showing an example of a conventional flexible wiring sheet. The flexible wiring sheet 1 is made of, for example, a synthetic resin, and has a flexible elongated sheet 2. On the upper surface of the sheet 2, a plurality of elongated conductors 3a to 3 are provided so as to extend along the entire length in the longitudinal direction of the sheet 2.
d are arranged in parallel at a predetermined distance. The plurality of conductors 3a to 3d are made of a metal material having excellent conductivity such as silver or copper. The formation of the conductors 3a to 3d is usually carried out by sticking a metal foil on the upper surface of the sheet 2 and then etching, or by plating one surface of the sheet 2 with the conductors 3a to 3d.

The remaining portions of the conductors 3a to 3d except for both end portions and the vicinity thereof are covered with a cover film 4 made of an insulating resin. The cover film 4 is formed by coating an insulating resin or laminating a film made of an insulating resin.
Since the flexible wiring sheet 1 has sufficient flexibility as a whole, the flexible wiring sheet 1 can be used to ensure a sufficient distance between the parts to be connected even when there are obstacles between small parts inside the device or between devices. It can be electrically connected.

[0004]

When an electric signal is applied to the flexible wiring sheet 1 as described above,
Electromagnetic noise may be radiated to the surroundings from the conductors 3a to 3d, and electromagnetic interference may be given to other peripheral electronic devices and cables. Therefore, conventionally, a method of passing the flexible wiring sheet 1 through a core made of a magnetic material such as ferrite has been partially adopted. However, in the method of passing the flexible wiring sheet 1 through such a ferrite core, a large space is required, and a complicated work of preparing a ferrite core as a separate component and fixing it to a case or the like is required.

Therefore, in order to reduce the size of electronic equipment, there is a demand for a flexible wiring sheet which emits less EMI noise to the surroundings. An object of the present invention is to provide a flexible wiring sheet provided with a structure for suppressing EMI noise radiation.

[0006]

The present invention comprises a long sheet having flexibility and a plurality of long conductors formed on the sheet, and at least one of the plurality of conductors is provided between the plurality of conductors. A sheet missing portion is formed in the sheet, and a magnetic material is provided so as to cover the plurality of conductors and the sheet at least in the region where the sheet missing portion is provided and to fill the sheet missing portion. A flexible wiring sheet having a resin layer formed therein.

[0007]

In the flexible wiring sheet, the magnetic substance-containing resin layer is formed around the plurality of conductors at least in the region where the sheet missing portion is formed.
Therefore, the radiation of EMI noise is suppressed by the action of the magnetic substance-containing resin layer. That is, the present invention is characterized in that the flexible wiring sheet itself is provided with the magnetic substance-containing resin layer to have an EMI noise suppressing effect.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be clarified by describing the embodiments of the present invention. 1 (a) and (b)
FIG. 1A is a plan view showing a flexible wiring sheet according to a first embodiment of the present invention and a sectional view taken along line BB.

The flexible wiring sheet 11 has a flexible elongated sheet 12 made of an insulating resin such as polyimide or polyester. On the upper surface of the long sheet 12, a plurality of long conductors 13a to 13a are formed.
d is formed so as to extend along the longitudinal direction of the sheet 12. The conductors 13a to 13d are made of a metal foil sheet 12.
It may be formed by a method of etching after being attached to the upper surface of the substrate, or an appropriate method such as application and curing of a conductive paste.

A magnetic substance-containing resin layer 14 is formed in the central portion of the sheet 12, and the magnetic substance-containing resin layer 14 covers a part of the plurality of conductors 13a to 13d. That is, in the portion where the magnetic substance-containing resin layer 14 is formed, as shown in FIGS.
A sheet missing portion 12a is formed between 3a to 13d. The magnetic substance-containing resin layer 14 is also filled in the sheet missing portion 12a. (See FIG. 1 (b)). Therefore, the flexible wiring sheet 11 of the present embodiment
Then, the magnetic substance-containing resin layer 14 allows the conductors 13a to 13a to
Since the periphery of 3d is surrounded, the conductors 13a to 13
Radiation of EMI noise due to the current flowing through d to the surroundings can be effectively suppressed.

The magnetic material-containing resin layer 14 may be made of a flexible resin such as a silicone resin in which magnetic powder such as ferrite is dispersed. Further, as the sheet missing portion, it is not always necessary to form a rectangular through hole as shown in FIG. 2A, and the sheet missing portion may be configured by an arbitrary planar through hole. When the magnetic material-containing resin layer 14 is formed so as to reach the vicinity of both ends of the sheet 12, a cutout having an open shape is formed at the end of the sheet near the end of the sheet 12, and the cutout is formed. May be used as the sheet missing portion.

In general, the flexible wiring sheet is covered with an insulating film or the like except the portions near the ends used for electrical connection of the conductors 13a to 13d in order to ensure electrical insulation from other cables and equipment. It is usually done. Therefore, the flexible wiring sheet 1 of the present embodiment
Also in No. 1, the periphery may be covered with the insulating film 15 as shown in the cross-sectional view in FIG.

The magnetic substance-containing resin layer 14 may be formed over the entire length of the flexible wiring sheet 11. In that case, the sheet missing portion 12a is shown in a partially cutaway plan view in FIG. As described above, it is necessary to form a large number of sheets in the respective regions between the conductors 13a to 13d at appropriate intervals along the length direction of the sheet 12. This is because otherwise, the magnetic material-containing resin layer cannot be sufficiently formed around the conductors 13a to 13d.

[0014]

According to the present invention, since the magnetic substance-containing resin layer is arranged around the plurality of conductors at least in the region where the sheet missing portion is provided, the magnetic substance-containing resin layer is exposed to the outside due to the current flowing through the conductor. The EMI noise radiation can be suppressed by the magnetic material-containing resin layer. Moreover, since the magnetic substance-containing resin layer contains a resin and a magnetic substance, it is possible to easily change the EMI noise removal characteristics by using magnetic substances having different magnetic substance contents and magnetic permeabilities. You can Not only that, the EMI noise removal characteristics can be easily changed by changing the thickness and area of the magnetic substance-containing resin layer.

Therefore, it is possible to provide a flexible wiring sheet in which an optimum EMI noise filter is integrated according to the application, and it is possible to omit an extra space for a filter for removing EMI noise which has been conventionally required. You can Therefore, it is possible to contribute to downsizing of electronic devices. Further, it becomes possible to omit the attachment of the filter and the electrical connection work for removing the EMI noise, which are conventionally required. Therefore, according to the present invention, it is possible to contribute to the reduction of the manufacturing cost of the electronic device.

[Brief description of drawings]

1A and 1B are a partially cutaway plan view and a sectional view taken along line BB of a flexible wiring sheet according to an embodiment of the present invention, respectively.

2A and 2B are a plan view and a cross-sectional view taken along the line BB for explaining a long sheet and a plurality of conductors used for the flexible wiring sheet of the embodiment.

FIG. 3 is a cross-sectional view showing an example in which an insulating film layer is provided around a flexible wiring sheet of an example.

FIG. 4 is a partial cutaway plan view for explaining an example in which a sheet missing portion is formed over the entire length.

5A and 5B are a plan view and a cross-sectional view taken along the line BB, respectively, for explaining a conventional flexible wiring sheet.

[Simple explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 ... Flexible wiring sheet 12 ... Elongate sheet 13a-13d ... Elongate conductor 14 ... Magnetic substance containing resin layer

Claims (1)

[Claims] 1. A long sheet having flexibility and a plurality of long conductors formed on the sheet, wherein a sheet missing portion is formed in the sheet in at least a part of the plurality of conductors. And a magnetic substance-containing resin layer is formed so as to cover a plurality of conductors and sheets in at least the region where the sheet missing portion is provided and to be filled in the sheet missing portion. Flexible wiring sheet characterized by: