JP2864908B2 - Flexible printed circuit board - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flexible printed circuit board used for electrically connecting two or more devices.

[0002]

2. Description of the Related Art As a wiring means for electrically connecting two devices, there is a flexible printed wiring board having a conductive pattern supported by a flexible insulating film.
This flexible printed wiring board is suitably used when the connected devices are not flat or when one device moves. As described above, since the flexible printed circuit board can flexibly correspond to the shape of the place of use, it has recently been suitably used for wiring in automobiles and the like.

[0003] However, even when two devices are connected by the flexible printed wiring board, if the distance between the devices varies, the flexible printed wiring board is in a state where a tensile force is applied. However, in the case of a vehicle having a lot of vibration such as an automobile, there is a possibility that the flexible printed circuit board may be damaged due to a change in distance between devices due to the vibration.

As a method of solving such a problem, a method of forming the flexible printed wiring board in a meandering shape has already been proposed as disclosed in Japanese Utility Model Laid-Open Publication No. 1-135758. In the flexible printed wiring board having the meandering shape as described above, even if there is a variation in the position of the two devices, it is possible to cope with this by expanding and contracting the meandering portion. Such a fear can be avoided.

[0005]

However, in the meandering flexible printed wiring board disclosed in the above-mentioned publication, due to its shape, many unnecessary parts are generated in the material during the production, and the yield is low. There was a problem of bad. Further, for the same reason, the flexible printed wiring board disclosed in the above-mentioned publication has a problem in that it requires a larger space than necessary.

Further, when the flexible printed circuit board disclosed in the above publication is wide, a slit parallel to the traveling direction of the conductive pattern is provided to improve the flexibility.
However, such a flexible printed circuit board is
When it is long, there is a problem that portions adjacent to each other across the slit overlap with each other, resulting in poor handling.

Further, since the flexible printed wiring board disclosed in the above publication has a meandering shape, an expensive mold is required for its manufacture, and there is a problem that the manufacturing cost is high.

The present invention has been made in view of the above circumstances, and does not receive a tensile force even if the position of an electric device or the like to be connected is shifted, and can be manufactured relatively inexpensively. It is an object of the present invention to provide a flexible printed circuit board that does not require an unnecessarily large space at an installation site.

Another object of the present invention is to provide a flexible printed circuit board which can be easily handled in a laying operation.

[0010]

According to a first aspect of the present invention, there is provided a flexible printed wiring board having a conductive pattern supported on a flexible insulating film, wherein at least one of the conductive patterns is formed substantially linearly. The one side edge meanders, so that a wide portion and a narrow portion alternately appearing in the conductive pattern along the traveling direction are formed in the conductive pattern, and the conductive pattern is formed in the conductive pattern and in the conductive pattern. A first slit that intersects with the traveling direction of the conductive pattern and does not divide the conductive pattern is formed on a portion of the narrow portion other than the minimum width portion.

According to a second aspect of the present invention, in the flexible printed wiring board according to the first aspect, both side edges of the conductive pattern meander symmetrically with each other.

According to a third aspect of the present invention, there is provided the flexible printed wiring board according to the first or second aspect, wherein the conductive pattern is formed on a non-formed portion corresponding to a side of a portion of the conductive pattern except for a widest part of the wide part. A second slit that intersects with the traveling direction is formed.

According to a fourth aspect of the present invention, in the flexible printed wiring board according to any one of the first to third aspects, the first slit formed in the conductive pattern forming portion is formed on the maximum width portion of the conductive pattern. Is formed.

According to a fifth aspect of the present invention, in the flexible printed wiring board according to the third aspect, the second slit formed in the non-formed portion of the conductive pattern is formed on a side of a minimum width portion of the conductive pattern due to the meandering. ing.

[0015]

According to the first aspect of the present invention, the width of the conductive pattern varies. By forming a slit that intersects the traveling direction of the conductive pattern on a portion of the conductive pattern other than the minimum width portion of the narrow portion, the slit is widened and the flexible printed wiring board is moved in the traveling direction of the conductive pattern. It can be extended.

According to the flexible printed wiring board of the second aspect, the width of the wide portion of the conductive pattern can be increased.

According to the third aspect of the present invention, since the second slit is formed, the amount of the conductive pattern of the flexible printed wiring board which can be extended in the traveling direction increases.

According to the flexible printed wiring board of the fourth aspect, the length of the slit provided in the conductive pattern forming portion can be maximized.

According to the flexible printed wiring board of the fifth aspect, the length of the second slit provided in the portion where the conductive pattern is not formed can be maximized.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A connector B is connected to one end or both ends of a flexible printed wiring board A according to the invention shown in FIG. 1 (only the connector B at one end is shown in FIG. 1).

As apparent from FIGS. 2 and 3, the flexible printed wiring board A includes a pair of upper and lower insulating films 1a and 1b, and a conductive pattern 2 sandwiched between the insulating films 1a and 1b. ing.

The insulating films 1a and 1b are made of an insulating resin material such as polyester or polyimide, and are adhered to each other.

The conductive pattern 2 is formed, for example, by etching a copper foil fixed on the lower insulating film 1b. As shown in FIG. 1, both side edges meander in a rectangular wave shape and symmetrically with each other. ing. Since the both side edges meander each other, the conductive pattern 2 has a shape in which the wide portions 2a and the narrow portions 2b alternately appear along the traveling direction. Further, since the both side edges meander in a rectangular wave shape, the wide portion 2a and the narrow portion 2b have an equal width in each portion.

In this flexible printed wiring board A, a plurality of first slits 3 are formed in a portion where the conductive pattern 2 is formed, and a plurality of second slits 4 are formed in a portion where the conductive pattern 2 is not formed. Is formed.

As shown in FIG. 2, the first slit 3 is positioned at a position corresponding to the wide portion 2a of the conductive pattern 2 in the direction of travel of the conductive pattern 2 (the direction of arrow F in FIG. 1). Are orthogonal. As shown in FIG. 8A, the first slit 3 has a notch provided with an arc portion 3a at both ends thereof, so that the first slit 3 is prevented from being torn from the end portion due to the presence of the arc portion 3a. The first slit 3 allows one end to reach a part where the conductive pattern 2 is not formed, but divides the conductive pattern 3 when both ends reach a part where the conductive pattern 3 is not formed. It must not be.

As shown in FIG. 3, the second slit 4 is formed in a non-formed portion of the conductive pattern 2 corresponding to the side of the narrow portion 2b of the conductive pattern 2. Like the first slit 3, the second slit 4 is also a cut perpendicular to the traveling direction of the conductive pattern 2,
One end reaches the side edge of the flexible printed wiring board A. At the other end of the second slit 4, an arc portion 4a similar to the arc portion 3a of the first slit 3 is formed.

The flexible printed wiring board A constructed as described above is used by connecting a connector B connected to an end thereof to an electric device (not shown). As shown in FIG. 4, the flexible printed wiring board A extends in the traveling direction of the conductive pattern 2 by expanding the first slit 3 and the second slit 4, and the entire length is substantially long. . Therefore, even if the distance between the electric devices is longer than the dimension of the flexible printed circuit board A because the position of each electric device is shifted, the flexible printed circuit board A may be damaged by the tensile force. Nothing.

In the above embodiment, the first slit 3 is provided in the portion where the conductive pattern 2 is formed, and the second slit 4 is provided in the portion where the conductive pattern 2 is not formed. In the flexible printed wiring board, only the first slit 3 may be provided. Such a flexible printed circuit board provided with only the first slit 3 also has a smaller amount of elongation than that provided with the second slit 4, but must be expanded in accordance with the displacement of the electric device. Can be.

Further, in the above-described embodiment, the case where both side edges of the conductive pattern 2 meander in a rectangular wave shape is shown. However, like the both side edges of the conductive pattern 12 of the flexible printed wiring board 1A shown in FIG. , It may meander in a sinusoidal manner. In this case, for convenience, the conductive pattern 1
If a portion having a width 2 larger than the average width is defined as a wide portion 12a and a portion having a width smaller than the average width is defined as a narrow portion 12b,
The first slit 13 corresponding to the slit 3 of the wide portion 1
A second slit 14, which is formed on 2a and corresponds to the second slit 4, is formed on the side of the minimum width portion of the narrow portion 12b. The first slit 13 is preferably provided at a position corresponding to the maximum width of the wide portion 12a, so that the total length of the first slit 13 can be set to the maximum. Also, the second slit 14
Is preferably formed on the side of the narrow portion 12b,
Thereby, the total length of the second slit 14 can be set to the maximum. The insulating films 11a and 11b of the flexible printed wiring board 1A are exactly the same as the insulating films 1a and 1b of the previous embodiment.

FIG. 6 shows another flexible printed wiring board 2A according to the present invention.

This flexible printed wiring board 2A
In this example, two sets of conductive patterns 22 having the same shape as the conductive pattern 2 on the flexible printed wiring board A of FIG. 1 described above are arranged in parallel between the insulating films 21a and 21b. The two sets of conductive patterns 22 are arranged symmetrically with respect to a predetermined line parallel to the traveling direction of these conductive patterns 22 (the direction of arrow F).

A first slit 23 is formed in the wide portion 22a of each conductive pattern 22, and a second slit 24 is formed in each of the middle portion of the narrow portion 22b and the outside of the narrow portion 22b. I have.

The flexible printed circuit board according to the present invention may have two conductive patterns or three or more conductive patterns as shown in FIG. Such a flexible printed circuit board can also obtain exactly the same effects as those of the flexible printed circuit board shown in FIGS.

FIG. 7 shows still another flexible printed wiring board 3A according to the present invention.

This flexible printed wiring board 3A
Supports a pair of conductive patterns 32A and 32B arranged in parallel between the insulating films 31a and 31b and having only opposing side edges meandering. Non-opposing side edges of the conductive patterns 32A and 32B are formed in a straight line. These conductive patterns 32A and 32B are symmetrically arranged.

The pair of conductive patterns 32A and 32B
The wide portions 32Aa, 32Ba and the narrow portions 32Ab, 3 alternately appear along the traveling direction of these conductive patterns 32A, 32B because only the opposing side edges meander.
2Bb.

The first slits 33A, 33B are formed with the wide portions 32Aa, 32Ba of the conductive patterns 32A, 32B.
, And one end protrudes from a portion where the conductive patterns 32A and 32B are not formed and reaches one end of the flexible printed wiring board 3A. On the other hand, the second slit 34 is formed at an intermediate portion between the narrow portions 32Ab and 32Bb of the conductive patterns 32A and 32B.

As described above, the conductive pattern of the flexible printed circuit board according to the present invention may have only one side edge meandering.

Further, another flexible printed wiring board according to the present invention may have only one of the conductive patterns 32A and 32B of the flexible printed wiring board shown in FIG.

In each of the above embodiments, the first slit provided at the position corresponding to the portion where the conductive pattern is formed and the second slit provided at the position corresponding to the portion where the conductive pattern is not formed are provided on the flexible printed circuit board. (See FIG. 8 (a)), these first and second slits may be elongated slits as shown in FIG. 8 (b) or as shown in FIG. 8 (c). It may be a simple elliptical slit.

The flexible printed wiring board of the present invention may have a connector connected to both ends thereof, or a connector connected only to one end, and the other end integrated with a printed board such as an electric device. May be formed.

[0042]

According to the first aspect, the flexible printed wiring board can be prevented from being damaged due to a partial pulling force because the flexible printed wiring board can be extended in accordance with the displacement of the electric device or the like. .

In addition, although the entire shape of the flexible printed wiring board, that is, the shape of the insulating film can be made linear, despite the fact that it is possible to cope with the displacement of electric equipment, etc., it is necessary to make the shape meandering. As a result, the manufacturing cost can be reduced. Also,
Similarly, for the same reason, there is an effect that the laying space of the flexible printed wiring board can be reduced as compared with the case where the insulating film is formed in a meandering shape.

Further, since the first slit intersecting with the traveling direction of the conductive pattern is provided, there is almost no overlap between adjacent portions across the slit as in the case of providing a slit parallel to the traveling direction. Even a long flexible printed circuit board can be handled relatively easily.

According to the second aspect, by increasing the first slit, the amount of extension of the flexible printed wiring board can be increased. It is possible to respond more flexibly.

According to the third aspect of the present invention, the amount of expansion of the conductive pattern of the flexible printed wiring board in the traveling direction is increased, so that the flexible printed wiring board can be more flexibly coped with misalignment of an electric device or the like connected to the flexible printed wiring board. It is possible to respond.

According to the fourth aspect, by increasing the length of the first slit, the extendable amount of the flexible printed wiring board can be increased.

According to the fifth aspect, by increasing the length of the second slit, the extendable amount of the flexible printed wiring board can be increased.

[Brief description of the drawings]

FIG. 1 is a partial plan view of a flexible printed wiring board according to the present invention.

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

FIG. 3 is a sectional view taken along the line III-III of FIG. 1;

FIG. 4 is a perspective view illustrating a use state of the flexible printed wiring board of FIG. 1;

FIG. 5 is a partial plan view of another flexible printed wiring board according to the present invention.

FIG. 6 is a partial plan view of still another flexible printed wiring board according to the present invention.

FIG. 7 is a partial plan view of still another flexible printed wiring board according to the present invention.

FIG. 8 is a diagram showing a shape of a slit.

[Explanation of symbols]

 1a, 1b, 11a, 11b Insulating film 21a, 21b, 31a, 31b Insulating film 2, 12, 22, 32A, 32B Conductive pattern 2a, 12a, 22a, 32Aa, 32Ba Wide portion 2b, 12b, 22b, 32Ab, 32Bb Width Narrow part 3, 13, 23, 33A, 33B First slit 4, 14, 24, 34 Second slit

Claims (5)

(57) [Claims] In a flexible printed wiring board in which a conductive pattern is supported on a flexible insulating film, at least one side edge of the conductive pattern formed in a substantially straight line meanders, thereby forming the conductive pattern. A wide part and a narrow part alternately appearing in the pattern along the traveling direction are formed, and on the conductive pattern forming part and on a part of the conductive pattern excluding the minimum width part of the narrow part, A first slit which intersects with the direction of travel of the conductive pattern and does not divide the conductive pattern. 2. The flexible printed circuit board according to claim 1, wherein both side edges of the conductive pattern meander symmetrically with respect to each other. 3. The flexible printed wiring board according to claim 1, wherein the conductive pattern is formed in a non-formed portion of the conductive pattern corresponding to a side of a portion of the conductive pattern excluding the widest part of the wide part. A flexible printed circuit board, wherein a second slit intersecting with the flexible printed circuit board is formed. 4. The flexible printed wiring board according to claim 1, wherein the first slit formed in the conductive pattern forming part is the maximum width part in the conductive pattern. A flexible printed circuit board formed on the flexible printed circuit board. 5. The flexible printed wiring board according to claim 3, wherein the second slit formed in the non-formed portion of the conductive pattern is formed on a side of a minimum width portion of the conductive pattern due to the meandering. A flexible printed wiring board characterized by being formed on a substrate.