JPH04263495A - Flexible wiring board - Google Patents

Abstract

PURPOSE:To enable a flexible wiring board which is used for wiring in a small space and can be built in a product as it is bent to be surely shielded and enhanced in strength without providing additional processes. CONSTITUTION:Covers 5a and 5b which cover the front and the rear of a main body 4 of a flexible wiring board 1 are formed into one piece together with the main body 4 so as to be bendable, a pattern 6 is formed on each of the covers 5a and 5b and connected to an earth pattern 3 formed on the main body 4, and the covers 5a and 5b are bonded to the main body 4 as they are bent covering the front and the rear side of the main body 4.

Description

[Detailed description of the invention]

0001

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

0002

[Prior Art] Flexible wiring boards are used in cameras, printers, audio equipment, and other consumer and industrial equipment to connect rigid printed wiring boards or for wiring in moving parts or in narrow spaces. . As shown in FIG. 4, the flexible wiring board 11 includes a base film 12 made of a flexible heat-resistant resin such as polyimide or polyester, a conductor pattern 13 formed by patterning copper foil bonded onto the base film 12, and the surface thereof. It is composed of a coverlay 14 that covers the. The coverlay 14 is made of an insulating film made of the same material as the base film and coated with an adhesive, or a thermosetting liquid resist.

0003

Since flexible wiring boards are used for wiring in narrow spaces, they are assembled into products in a folded state. Therefore, when the various signal line patterns formed on the flexible wiring board are arranged in such a manner that they intersect and overlap, there are problems in that crosstalk occurs at the intersections, and the wiring portions tend to pick up noise. In addition, in order to increase the flexibility of flexible wiring boards,
Since it is formed thinly, there is a problem that its strength is weak.

The present invention has been made in view of the above-mentioned problems, and its purpose is to be able to reliably shield the wiring portion and increase the strength, while requiring no extra manufacturing steps. The purpose is to provide an unnecessary flexible wiring board.

[0005]

[Means for Solving the Problems] In order to achieve the above object, in the present invention, a cover portion covering both the front and back sides of the main body portion of a flexible wiring board is formed integrally with the main body portion so as to be foldable, and each cover portion is formed integrally with the main body portion. A pattern was formed and the pattern was connected to a ground pattern formed on the main body, and the cover was bent to cover both the front and back surfaces of the main body and adhered to the main body.

[0006]

[Function] The pattern formed on the cover part that covers both the front and back sides of the main body part, on which patterns of various signal lines of the flexible wiring board are formed, serves as a shield layer, and the flexible wiring board is attached to the product in a bent state. This prevents crosstalk from occurring even if various signal line patterns overlap in a crossing state. Moreover, the presence of the cover portion increases the strength of the flexible wiring board, and increases reliability when the flexible wiring board is folded and assembled into a narrow accommodation location.

[0007]

[Example] (Example 1) Hereinafter, a first example embodying the present invention will be described.
An example will be explained according to FIG. As shown in FIG. 1(a), the flexible wiring board 1 has a main body 4 on which a signal line pattern 2 and a ground line pattern 3 are formed.
A cover part 5 that covers both the front and back sides of is formed integrally so as to be foldable. The cover portion 5 is formed in such a manner that two cover portions 5a and 5b formed in substantially the same shape as the main body portion 4 are continuous via a connecting portion 5c. Each cover part 5a, 5
A lattice pattern 6 constituting a shield layer is formed on almost the entire surface of b. The pattern 6 is connected to the ground wire pattern 3 formed on the main body part 4. The cover part 5 is bent at the connecting part 5c, as shown in FIG. 1(b).
As shown in FIG.
is glued to.

[0008] The cover portion 5 is made as a part of the flexible wiring board 1, and no extra steps are required for making the cover portion 5. That is, pattern formation and the like are performed on the entire structure including the cover portion 5 as one flexible wiring board. Therefore, the cover part is made separately from the main body part 4,
Compared to the case where it is attached to the main body part 4, the processing effort is reduced. Moreover, since the pattern 6 formed on the cover parts 5a and 5b is connected to the ground wire pattern 3 as one wiring of the flexible wiring board 1, it is easy to connect it to GND.

The flexible wiring board 1 formed as described above is reinforced by the cover part 5 that covers both the front and back sides of the main body part 4, increasing its strength, so that when it is assembled into a product in a bent state in a narrow space, will be prevented from being damaged. Furthermore, since the pattern 6 as a shield layer is present on both the front and back sides of the main body 4, even if the flexible wiring board 1 is assembled into a product in a folded state and the signal line patterns 2 intersect, the signal Line pattern 2
The occurrence of crosstalk between the two is reliably prevented. Furthermore, even if the flexible wiring board 1 is placed near other wiring parts other than the flexible wiring board 1, it is certain that the signal line pattern 2 will pick up noise or cause noise in other wiring parts. is prevented.

When the flexible wiring board is made into a multilayer structure with shield layers on both sides and the base film and coverlay of the main body 4 are thickened to increase strength, the flexibility decreases and it cannot be accommodated in a narrow space. becomes difficult to do. However, in the present invention, the cover portions 5a, 5b and the main body portion 4 are not completely bonded over the entire surface, so even if the cover portions 5a, 5b cover both sides of the main body portion 4, their flexibility is limited. It does not deteriorate much and can be assembled into a product in a narrow space while being folded.

(Embodiment 2) Next, a second embodiment will be explained with reference to FIG. In this embodiment, the shape of the flexible wiring board 1 is different from the previous embodiment. That is, the flexible wiring board 1 is formed with its end bent at right angles, and the cover parts 5a and 5b are arranged in one row in the longitudinal direction instead of being arranged in parallel. is formed.

It should be noted that the present invention is not limited to the two embodiments described above; for example, cover portions 5a and 5b may be formed on both sides of the main body portion 4 as shown in FIG. In this case, two ground wire patterns 3 are provided, and each cover part 5a, 5
The patterns 6 formed in b are connected to different ground wire patterns 3, respectively. Further, the main body part 4 may be covered with a plurality of cover parts 5, which is effective when the flexible wiring board is long or has a complicated shape. Further, the pattern 6 may be a solid pattern instead of a grid pattern, but a grid pattern is more flexible. Furthermore, the main body part 4 may be wired on both sides, or a pad for mounting an electronic component may be provided on the main body part 4, the electronic component may be mounted, and the top may be covered with a cover part.

[0013]

[Effects of the Invention] As detailed above, according to the present invention, the pattern formed on the cover portion provided to cover both the front and back surfaces of the main body portion functions as a shield layer, and the wiring portion is reliably shielded. It is possible to improve the reliability of the flexible wiring board since it is possible to increase the strength and improve the reliability of the flexible wiring board. Further, there is an excellent effect that there is no need to provide an extra process for creating the cover part, and the processing time and effort is almost the same as in the case of conventional flexible wiring boards.

[Brief explanation of the drawing]

FIG. 1 shows a flexible wiring board of a first embodiment, (a
) is a plan view showing a state in which the cover part is unfolded, and (b) is a plan view showing a state in which the main body part is covered with the cover part.

FIG. 2 shows a flexible wiring board of a second embodiment, (a
) is a plan view showing a state in which the cover part is unfolded, and (b) is a plan view showing a state in which the main body part is covered with the cover part.

FIG. 3 is a plan view of a modified example of a flexible wiring board in an expanded state;

FIG. 4 is a sectional view of a conventional flexible wiring board.

[Explanation of symbols]

1...Flexible wiring board, 2...Signal line pattern, 3...
Ground wire pattern, 4...Main body part, 5...Cover part, 5a
...Cover part, 5b...Cover part, 5c...Connection part, 6...Pattern.

Claims (1)

[Claims] [Claim 1] The main body of the flexible wiring board (1) (
The cover parts (5a, 5b) covering both the front and back sides of 4) are foldably formed integrally with the main body part (4), and each cover part (5)
a, 5b), and connect the pattern (6) to the ground wire pattern (3) formed on the main body part (4), and connect the cover part (5a, 5b) to the main body part. A flexible wiring board characterized by being bent to cover both the front and back sides of (4) and bonded to the main body (4).