JP2003258388A - Arranging structure of flexible printed circuit board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an arranging structure of an FPC (flexible printed circuit board) capable of reinforcing mechanical weak points of the FPC and inhibiting disconnection of a conductor and rupture of the FPC itself. <P>SOLUTION: This is an arranging structure of the FPC in which a part of the FPC is bent and arranged at a location on which the FPC is repeatedly bent and a supporting material 20 having a cylindrical surface is arranged inside the bent location of the FPC 10. Thus, the supporting material 20 is arranged inside the bent location in the FPC 10, so as to prevent the bent part of the FPC 10 from being crushed or broken. Consequently, the disconnection of the conductor and the rupture of the FPC are inhibited. <P>COPYRIGHT: (C)2003,JPO

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 (FPC) layout structure. In particular, the present invention relates to an FPC layout structure that can reduce the probability of conductor breakage even if repeated bending is applied.

[0002]

2. Description of the Related Art In recent years, the development of mobile phones has been remarkable. In particular, recently, in consideration of the large screen of the display unit, compactness, fashionability, and protection of operation buttons, the folding (shell-type) mobile phone has become the mainstream, and this trend will continue in the future. Expected to continue.

FIG. 5 (A) is a schematic view of the shell type mobile phone in an open state, FIG. 5 (C) is a schematic view of the closed state, and FIG. 5 (B) is an FPC in the open state of the mobile phone. Schematic diagram, (D) is a schematic diagram of the FPC in a closed state. The shell-type mobile phone 60 has a structure in which a display unit 62 such as a liquid crystal screen is foldably connected by a hinge 63 to a key switch unit 61 in which operation buttons (not shown) are arranged. The key switch unit 61 and the display unit 62 are electrically connected via the FPC 64.

As shown in FIG. 4, for example, the FPC used here has an offset type shape in which straight portions 50 at both ends are connected by S-shaped bent portions 51. It has a fold resistance when the key switch part and the display part are repeatedly bent.

At this time, the bent portion of the FPC is arranged in the cylindrical member of the hinge, but conventionally, no special structure for holding the winding shape of the FPC wound once was provided.

[0006]

However, as described above,
In the FPC layout structure, there is a problem that the winding diameter of the FPC becomes too small due to the opening and closing of the display section and the key switch section. Conventional F
The arrangement structure of the PC is not provided with any means for maintaining the winding shape of the FPC having one winding. Therefore, when the mobile phone is repeatedly opened and closed, the winding diameter may be reduced or the winding shape may be collapsed, as illustrated in FIG. 5D. As a result, poor continuity and breakage of the conductor occur, and in some cases, the FPC is broken.

Therefore, a main object of the present invention is to provide an FPC arranging structure capable of suppressing disconnection of a conductor in a bent FPC and breakage of the FPC itself.

[0008]

The present invention achieves the above object by providing a shape-retaining means for an FPC that is arranged in a bent manner.

That is, the arrangement structure of the flexible printed wiring board according to the present invention is the arrangement structure of the flexible printed wiring board in which a part of the flexible printed wiring board is bent and arranged at the position where the bending is repeatedly applied. It is characterized in that a supporting member having a cylindrical surface is arranged inside the bent portion of the wiring board.

By arranging the support material inside the bent portion of the FPC, it is possible to prevent the bent portion of the FPC from being crushed or broken.
Suppresses conductor breaks and FPC breaks.

The support material may have any shape as long as it has a cylindrical surface. Generally, a pipe shape is suitable. In particular,
A cylindrical member in which a part of the peripheral surface is cut out in the axial direction is preferable because elasticity of the support material itself in the diameter reducing direction can be obtained.

The support material is preferably plastic or metal. For example, polyethylene, polypropylene, polyethylene terephthalate, aluminum or copper can be used. Of course, not only these materials alone but also a laminated / composite material can be used.

Although the thickness of the support material depends on the material, it is generally preferably about 0.2 to 1.0 mm.

The arrangement of the support material and the FPC is preferably such that the FPC is wound around or attached to the support material. Then, the support material and the FPC may be fixed by an adhesive, or the support material may be provided with an engaging portion, and the FPC may be sandwiched between the engaging portions so as to be fixed. When an adhesive is used, the support material and the FPC may be wholly bonded or partially bonded.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below. (Example 1) The FPC used in the arrangement structure of the present invention has an offset type shape in which linear portions at both ends are connected by S-shaped bent portions, as shown in FIG. In general, such an FPC has connection electrode portions (not shown) for connection with a mating substrate, which are not shown. The conductors other than the connecting electrodes are sandwiched between resin films such as polyimide to form an FPC. In this example, the conductor is composed of 18 μm thick copper foil,
Each of these conductors is sandwiched between a polyimide upper surface resin film and a lower surface resin film having a thickness of 12.5 μm.

Such an FPC and supporting material are shown in FIG. 1 (A).
In this case, the polyethylene pipe 20 having a part of the peripheral surface cut out in the axial direction was used as the supporting material. As shown in FIG. 1 (B), the FPC 10 is wound once around the outer circumference of the polyethylene pipe 20.
The number of windings is not particularly limited. Here, the FPC is simply wrapped around the support material, and no bonding is performed.

The support material and the FPC are used by arranging them in the hinge part of a shell type mobile phone, for example.

A repeated bending test was performed using the FPC and the support material thus configured. For comparison, without support
The same bending test was performed for the arrangement structure in which only the FPC was wound once. The test conditions are as follows. The FPC is mounted on the actual shell type mobile phone, and the opening and closing operations of the key switch section and the display section are repeated. Here, the opening / closing operation was repeated in a 2-second cycle between "fully opened" and "closed". FPC
The inner diameter of is about 5 mmφ.

As a result, in the FPC arrangement structure using the support material, no conductor breakage or FPC breakage was observed after repeated bending of 100,000 times. In contrast, FP without support material
Regarding the arrangement structure of C, the conductor was broken after repeated bending of 80,000 times.

(Example 2) In Example 1 described above, F was used as the support material.
Although the PC is wound once, it may be wound 0.5 times as shown in FIG. In this way, pipe 20 to 0.5 FPC10
Even with the wound arrangement structure, it is possible to prevent the bent shape of the FPC from being reduced as in the first embodiment, and it is possible to suppress conductor breakage.

(Embodiment 3) Further, as shown in FIG.
The FPC 10 may be arranged in a corrugated manner along the cylindrical support member 30. Even with such an arrangement structure, as in Example 1, F
It is possible to prevent the bent shape of the PC from being reduced, and it is possible to suppress conductor breakage.

[0022]

As described above, according to the present invention,
By arranging the support material in the bent part of the FPC, the bent part of the FPC can be kept in shape and the conductor disconnection and
The probability of FPC breakage can be reduced.

[Brief description of drawings]

FIG. 1A is an explanatory view showing a state before the FPC is wound around a support material, and FIG. 1B is an explanatory view of the arrangement structure of the present invention showing a state after the FPC is wound around the support material.

FIG. 2 is an explanatory view of an arrangement structure of the present invention in which an FPC is wound around a support member half way.

FIG. 3 is an explanatory view of an arrangement structure of the present invention in which an FPC is arranged along a corrugated shape on a support material.

FIG. 4 is a schematic explanatory diagram of a conventionally used FPC.

5A and 5B are explanatory diagrams showing changes in the shape of an FPC bent portion in a mobile phone, where FIG. 5A is a schematic view of a shell-type mobile phone in an open state, and FIG. 5C is a schematic view of a closed state. B) is a schematic diagram of the FPC when the mobile phone is opened, and (D) is a schematic diagram of the FPC when the mobile phone is closed.

[Explanation of symbols]

10 FPC 20 Pipe 30 Support member 50 Straight section 51
Bending part 60 Mobile phone 61 Key switch part 62 Display part 63
Hinge 64 FPC

Claims (5)

[Claims] 1. An arrangement structure of a flexible printed wiring board in which a part of the flexible printed wiring board is bent and arranged at a portion where repeated bending acts, wherein the flexible printed wiring board has an inner side of the bent portion of the flexible printed wiring board.
An arrangement structure of a flexible printed wiring board, characterized in that a supporting material having a cylindrical surface is arranged. 2. The arrangement structure of a flexible printed wiring board according to claim 1, wherein the bent portion of the flexible printed wiring board is wound around the support material. 3. The arrangement structure of the flexible printed wiring board according to claim 1, wherein the bent portion of the flexible printed wiring board is mounted on the support member. 4. The arrangement structure of a flexible printed wiring board according to claim 1, wherein the support material is made of plastic. 5. The arrangement structure for a flexible printed wiring board according to claim 1, wherein the support member has a cylindrical shape in which a part of a peripheral surface is axially cut out.