JP2000223797A - Flexible wiring board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily bend a flexible wiring board in a prescribed position, to prevent the disconnection of a wiring pattern when the board is bent and to accurately cut the flexible wiring board. SOLUTION: In this flexible wiring board 5 which can be bent, a conductor layer is laminated on a flexible insulator board. The flexible wiring board is featured in such a way that pattern lacking regions, in which the conductor layer does not exist on the insulator board, and which are composed of a plurality of independent small-area pattern blank parts 4, are formed in positions along bending lines (A-A', B-B') on the flexible wiring board in an all-over pattern 3 in the wiring patterns.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bendable flexible wiring board in which a wiring pattern is formed on a flexible insulating substrate, and more particularly to a flexible wiring board while preventing damage to the wiring pattern and the flexible wiring board. The present invention relates to a technique for easily bending a desired part.

[0002]

2. Description of the Related Art A flexible wiring board has been used as a wiring board in an electronic circuit device and a substrate for mounting electronic components. This flexible wiring board is obtained by laminating a conductor layer on a flexible insulating film such as a polymer film to form a wiring pattern, and can be bent or bent as necessary. In addition, since it is in the form of a film, there is also an advantage that the wiring board can be reduced in thickness.

Therefore, by utilizing such characteristics, for example, in a limited space between a mechanism of an optical system housed inside the camera body and a housing of the camera like an electronic camera, It can be used when the electronic circuit must be efficiently stored. In this case, the electronic components are mounted on a thin flexible wiring board and the wiring inside the camera is performed by the wiring pattern formed on the same board, thereby forming an electronic circuit according to the shape of the space inside the camera body. Since mounting can be performed, mounting efficiency is greatly improved.

Further, when wiring is performed to an electronic device having a movable portion such as a printer head of a serial printer, the movement of the printer head is prevented by connecting the drive circuit and the printer head with a flexible wiring board. And a drive signal can be supplied.

[0005]

When such a flexible wiring board is mounted on an electronic device, the flexible wiring board is bent at a specific position due to the shape of the mounted portion and the wiring layout. Varies depending on the formation ratio of the wiring pattern laminated on the insulator film. For example, in a portion where the wiring pattern is a very wide solid pattern, the area occupied by the conductive layer having high hardness becomes large, so that the flexible wiring board in that portion becomes hard and hard to be bent.

For this reason, the conventional flexible wiring board has a disadvantage that it is difficult to bend at a desired position depending on the state of the wiring pattern. Further, when the hardness of the flexible wiring board is uniform throughout, there is also a disadvantage that the bending position varies.

In order to solve this problem, for example, Japanese Utility Model Registration No. 25553628 discloses a flexible wiring board in which a linear blank pattern portion is formed in a solid pattern.

FIG. 8 is an enlarged plan view showing a bent portion of a flexible wiring board disclosed in Utility Model Registration No. 25553628, and FIG. 9 shows a relationship between a blank pattern portion and a bending line in the flexible wiring board shown in FIG. FIG.

In a flexible wiring board 15 shown in FIGS. 8 and 9, a conductor layer is laminated on a flexible insulating substrate 11 such as a polymer film, and a wiring pattern 12 is formed.
Are formed. When this flexible wiring board 15 is mounted on an electronic device, a bending line (A-
A 'and BB', and CC 'in FIG. 9), and the solid pattern 13 of the wiring pattern 12 has no linear conductor layer along each bending line. Blank pattern portion 14 is formed.

In the conventional flexible wiring board 15 having such a configuration, a single linear blank pattern portion 14 is formed along each bending line, and the blank pattern portion 14 is formed by a linear bending having a small hardness. The flexible wiring board 15 can be easily bent in the vicinity of the bending line even if it is a region where the easy pattern is formed and the solid pattern is formed, but the strength of the pattern may be reduced at the bent portion. For this reason, for example, in applications where the flexible wiring board is repeatedly bent and stretched frequently, the solid pattern and the breakage of the board due to the bending are more accurately prevented, and the bending at the bent portion is maintained while maintaining the strength of the bent portion to some extent. There is a demand for a flexible wiring board that facilitates the above.

Further, when a linear blank pattern portion 14 is formed in the solid pattern 13 as in the conventional flexible wiring board 15, the electric resistance of the solid pattern 13 is reduced because the conductive path is narrowed or the total path length is increased. This increases the impedance when used at a high frequency or the like, so that, for example, the grounding effect of the solid pattern 13 cannot be sufficiently achieved. Therefore, a flexible wiring board that facilitates bending at a bent portion without increasing the electrical impedance of the solid pattern is also desired.

An object of the present invention is to make it possible to easily bend a flexible wiring board at a predetermined position, and to properly prevent a solid pattern and a board from being damaged due to the bending.

Another object of the present invention is to facilitate bending of a flexible wiring board at a predetermined position without increasing the electrical impedance of a solid pattern.

[0014]

To achieve the above and other objects, according to the present invention, a conductor layer is laminated on a flexible insulating substrate, and a wiring pattern is formed by the conductor layer. A bendable flexible wiring board, wherein a pattern-missing area is provided at a position along a bending line of the flexible wiring board in a solid pattern in the wiring pattern, and the pattern-missing area is provided on the insulator substrate. A flexible wiring board comprising a plurality of independent small area pattern blank portions without a conductor layer is provided. With such a configuration, the flexible wiring substrate can be easily bent at a predetermined position, and the solid pattern and the damage of the substrate due to the bending can be accurately prevented. Further, the flexible wiring board can be easily bent at a predetermined position without increasing the electrical impedance of the solid pattern.

In this case, at least one of the plurality of pattern blank portions may be configured to have a vertex on a bending line of the flexible wiring board. This makes it easier to specify the bending line, and the flexible wiring board can be bent more accurately along the bending line. Further, the flexible wiring board is not deviated from a predetermined bending position and bent.

Further, in this case, the plurality of pattern blank portions may be configured so that pattern blank portions having different sizes are mixed. Thereby, it is possible to accurately prevent the small pattern blank portion from being deviated from the bending line by regulating the bending position and to bend, and it is possible to make the flexible wiring board easier to bend due to the presence of the large pattern blank portion. Become.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A flexible wiring board according to the present invention will be described below with reference to the drawings.

FIG. 1 is an enlarged plan view of a portion around a bent portion of the flexible wiring board 5 according to the first embodiment of the present invention, and FIG. 2 is a view showing a schematic shape of the entire flexible wiring board 5 of FIG. FIG. In the flexible wiring board 5 shown in these figures, a wiring pattern 2 is formed by laminating a conductor layer on a flexible insulating substrate 1 such as a polymer film.

When the flexible wiring board 5 is mounted on an electronic device, it is to be bent at the portions indicated by the bending lines AA 'and BB'. Therefore, along these folding lines AA 'and BB', in the solid pattern 3 of the wiring pattern 2, a pattern blank portion or blank of a plurality of small areas where no conductor layer is present on the flexible wiring board. A pattern section 4 is formed, and a series of blank pattern sections 4 and a conductor forming section 6 having a conductor layer on a flexible wiring board between the blank pattern sections 4 along each bending line are formed as a whole. A linear easy-to-bend portion having a lower hardness than the solid pattern portions on both sides of the bending line is formed.

FIG. 3 is a partially enlarged plan view schematically showing the periphery of a bending line (indicated by CC 'in FIG. 3) of such a flexible wiring board. As shown in FIG. 3, a plurality of, for example, four, small area blank pattern portions 4 are formed along the folding line CC ′ in the solid pattern 3 formed on the insulator substrate 1. I have. The shape of each blank pattern portion 4 can be, for example, a rectangular shape or a square shape as shown in FIG. Further, the shape and size of each of the blank pattern portions 4 may be all the same, but may be different. The conductor forming portion 6 exists between the adjacent blank pattern portions 4. In addition, in order to facilitate understanding, the pattern lacking region 7 formed by the blank pattern portion 4 and the conductor forming portion 6 as a whole.
Is schematically indicated by a dotted line in the figure.

In the flexible wiring board of this embodiment,
In each bending line, the blank pattern portions 4 of a plurality of independent small areas are continuously formed with the conductor forming portion 6 interposed therebetween, and the conductor formation between each blank pattern portion 4 and the blank pattern portion is performed. By forming the linear pattern lacking region 7 (region surrounded by the dotted line in FIG. 3) as a whole by connecting the portion 6 linearly, the amount of the conductive member having high hardness is relatively small, that is, A linear easy-to-bend portion having a relatively lower hardness than the regions on both sides is formed along the bending line. The flexible wiring substrate can be easily bent along the bending line by the linear bending portion including the blank pattern portion 4 and the conductor forming portion 6, while a single pattern as shown in FIGS. Compared to a conventional flexible wiring board in which a linear easy-to-bend portion including only a blank portion is formed, the conductor forming portion 6 is provided in the easily bendable portion.
The amount of the conductor member can be reduced by the presence of, and the strength of the flexible wiring board can be increased. Therefore, it is possible to accurately prevent the flexible wiring board from being damaged or cut at the time of bending.
In addition, since the blank pattern portions 4 can be arranged in a well-balanced manner, a load is not applied only to a specific portion of the solid pattern at the time of bending, so that the solid pattern can be prevented from being damaged or broken.

Further, in the flexible wiring board of the present embodiment, the conductor forming portions 6 between the blank pattern portions 4 also function as conductive paths, and are formed between the solid pattern portions on both sides of the bending line (or the easily bending portion). The electrical resistance and electrical impedance do not increase so much even if an easily bendable portion is formed in the solid pattern 3. Therefore, the impedance can be kept low even when used at a high frequency, and for example, the effect of grounding by a solid pattern can be sufficiently maintained and achieved. Further, the potential difference between each part of the solid pattern can be made very small. Further, even if a part of the solid pattern 3 (or the conductor forming portion 6) is damaged or disconnected when the flexible wiring board is bent, the solid pattern 3
Is reliably ensured by the remaining conductor forming portion 6.

FIG. 4 is a partially enlarged plan view schematically showing the vicinity of a bent portion of the flexible wiring board according to the second embodiment of the present invention. The flexible wiring board according to the first embodiment of FIG. Is different in the shape and size of the blank pattern portion 4 in the small area.

In the flexible wiring board shown in FIG.
The shape of each blank pattern portion 4 is circular. Each blank pattern portion 4 having a circular shape preferably has a respective center position on the folding line CC ′. The size of each blank pattern portion 4 may be the same, but blank pattern portions having different sizes may be mixed. In the flexible wiring board of FIG. 4, the size of the blank pattern portions at both ends is smaller than that of the middle blank pattern portion, but the size of the blank pattern portions at both ends may be larger than that of the middle blank pattern portion. . Further, the size of the blank pattern portion at an arbitrary number and position in the plurality of blank pattern portions can be made larger or smaller than the others. The size of all the blank pattern portions may be different. The flexible wiring board of the present embodiment has substantially the same effect as the flexible wiring board of FIG. Stress such as stress is less likely to occur. Therefore, the solid pattern is less likely to be damaged near the blank pattern portion 4 when the flexible wiring board is bent. In addition, since blank pattern portions having different sizes are mixed, it is possible to accurately prevent a small blank pattern portion from being deviated from a folding line by restricting a bending position and forming a large blank pattern portion. By doing so, the flexible wiring board can be more easily bent.

FIG. 5 is an enlarged partial plan view schematically showing the area around the bent portion of the flexible wiring board according to the third embodiment of the present invention. The shape and size of the part 4 are different.

In the flexible wiring board shown in FIG.
The shape of each blank pattern portion 4 is an elliptical shape having a major axis or a minor axis in the direction of the folding line CC ′. As shown in FIG. 5, a plurality of blank pattern portions 4 are formed by combining a blank pattern portion having an elliptical shape having a major axis in a folding line direction and a blank pattern portion having an elliptical shape having a minor axis in a folding line direction. However, it may be composed of only one. The flexible wiring board of the present embodiment has substantially the same effect as the flexible wiring board of FIG. 3, and furthermore, since each blank pattern portion 4 is elliptical and has no corners,
Stress such as stress is less likely to be generated near the blank pattern portion 4 during bending. Therefore, the solid pattern is hardly damaged near the blank pattern portion. In addition, since the elliptical shape has a long axis or a short axis, more preferably a long axis, in the direction of the bending line, the bending position can be regulated, and the bending can be accurately prevented from being shifted from the bending line.

FIG. 6 is a partially enlarged plan view showing a simplified area around a bent portion of a flexible wiring board according to a fourth embodiment of the present invention. The shape and size of the part 4 are different.

In the flexible wiring board shown in FIG.
The shape of each blank pattern portion 4 is a diamond shape having a vertex on the folding line CC ′. The flexible wiring board of the present embodiment has substantially the same effect as the flexible wiring board of FIG. 3, and furthermore, since each blank pattern portion 4 has a vertex on the folding line CC ′, the bending line C
On the -C ', the amount of the conductor member is smallest, that is, the hardness is small. Therefore, bending along the bending line CC ′ can be performed very easily. Further, the bending line can be specified without forming the blank pattern portion 4 particularly thin, and the flexible wiring board is not deviated from a predetermined bending position and bent.

In addition to the diamond shape, each blank pattern portion 4
Has the same effect as long as the shape has a vertex on the folding line, for example, a triangle having a vertex on the folding line CC ′. In addition, the effect described above is greater if all of the blank pattern portions 4 have a vertex on the folding line as shown in FIG. 6, but at least one of the plurality of blank pattern portions has a vertex on the folding line. It is effective as long as it has a shape. Further, even if the shape of the blank pattern portion 4 does not have a vertex on the folding line, the conductor formation ratio on the folding line is particularly smaller than that of the portion adjacent to the folding line, such as a convex shape or a curved figure. The effect is obtained even if the shape has the top on the bending line or if the top is turned upside down.

FIG. 7 is a partially enlarged plan view showing a simplified area around a bent portion of a flexible wiring board according to a fifth embodiment of the present invention. The shape and size of the part 4 are different.

In the flexible wiring board shown in FIG.
The blank pattern portions at both ends among the blank pattern portions 4 of the plurality of small areas have a vertex on the folding line CC ′, for example, a shape such as a triangle, and the middle blank pattern portion has an arbitrary shape such as a square, for example. It can be. The flexible wiring board of the present embodiment, in particular, by forming the shape of the blank pattern portion at both ends to have a vertex on the bending line, the vertex functions as a bending position regulating portion,
The bending line can be easily specified regardless of the shape of the intermediate blank pattern portion, and the flexible wiring board is not deviated from the predetermined bending position and bent, and the same effect as that of the flexible wiring board of FIG. 6 is sufficiently obtained. be able to. In addition, the blank pattern portion having a shape having a vertex on the folding line is not required to be at both ends of the plurality of blank pattern portions, but may be near both ends.

Although specific embodiments have been described, the present invention provides
In a bendable flexible wiring board in which a wiring pattern is formed on a flexible insulating substrate, a plurality of small area pattern blanks are provided at positions along a bending line of the solid pattern flexible wiring board in the wiring pattern. The configuration is not limited to the above-described embodiment as long as the configuration is such that a linear easy-to-bend portion formed of the conductor forming portion between the pattern blank portions is formed. For example, the number of blank pattern portions in the small area constituting the linear easy-to-bend portion is not limited to four or five as in FIGS. 3 to 7, and may be two or more. The shape and size of each blank pattern portion can be arbitrarily selected from various shapes and sizes other than FIGS. The shape and size of each of the plurality of blank pattern portions may be all the same, but may be configured with a plurality of different shapes and sizes. Further, the interval between the blank pattern portions, that is, the size of each conductor forming portion 6 can be the same, but may be different.

[0033]

As described above, according to the present invention, a linear easy-to-bend portion composed of a blank pattern portion of a small area and a conductor forming portion between the blank pattern portions along the bending line of the flexible wiring board. Is formed, it is extremely easy to bend the substrate at the bending position, the strength of the bent portion can be maintained to some extent, and the flexible wiring substrate is not damaged or cut. Further, no load is applied only to a specific portion of the wiring pattern at the time of bending, and the wiring pattern is not damaged or disconnected.

Further, since the conductive path of the solid pattern is ensured by the conductor forming portion between the blank pattern portions, an increase in the electrical impedance of the solid pattern can be suppressed even if the easily bendable portion is formed. The impedance of the solid pattern can be reduced even when used at a high frequency, and for example, the effect of grounding by the solid pattern can be maintained.

[Brief description of the drawings]

FIG. 1 is an enlarged plan view around a bent portion of a flexible wiring board according to a first embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a schematic shape of the entire flexible wiring board of FIG. 1;

FIG. 3 is a partially enlarged plan view schematically showing a periphery of a bent portion of the flexible wiring board according to the first embodiment of the present invention.

FIG. 4 is a partially enlarged plan view schematically showing a periphery of a bent portion of a flexible wiring board according to a second embodiment of the present invention.

FIG. 5 is a partially enlarged plan view schematically showing the vicinity of a bent portion of a flexible wiring board according to a third embodiment of the present invention.

FIG. 6 is a partially enlarged plan view schematically showing a periphery of a bent portion of a flexible wiring board according to a fourth embodiment of the present invention.

FIG. 7 is a partially enlarged plan view schematically showing the vicinity of a bent portion of a flexible wiring board according to a fifth embodiment of the present invention.

FIG. 8 is an enlarged plan view around a bent portion of a conventional flexible wiring board.

FIG. 9 is a partially enlarged plan view showing the vicinity of a bent portion of the flexible wiring board of FIG. 7;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Insulator board 2 Wiring pattern 3 Solid pattern 4 Blank pattern part 5 Flexible wiring board 6 Conductor formation part 7 Pattern missing area 11 Insulator substrate 12 Wiring pattern 13 Solid pattern 14 Blank pattern part 15 Flexible wiring board

Claims (3)

[Claims] 1. A bendable flexible wiring board in which a conductive layer is laminated on a flexible insulating substrate and a wiring pattern is formed by the conductive layer, wherein the solid pattern in the wiring pattern is A pattern lacking region is provided at a position along a bending line of the flexible wiring board, and the pattern lacking region is formed of a plurality of independent small area pattern blank portions without the conductor layer on the insulator substrate. Flexible wiring board. 2. The flexible wiring board according to claim 1, wherein at least one of the plurality of pattern blank portions has a shape having a vertex on a bending line of the flexible wiring board. 3. The flexible wiring board according to claim 1, wherein the plurality of pattern blank portions include pattern blank portions having different sizes.