Flexible wiring member

The present invention relates to a flexible wiring body such as a flexible printed wiring board (FPC: Flexible Printed Circuits) and a flexible flat cable (FFC: Flexible Flat Cable) having a wiring pattern for shielding as an electromagnetic wave shielding layer, and more specifically, it is repeated. The present invention relates to a flexible wiring body capable of improving bending strength and flexibility by preventing disconnection of shield pattern wiring due to bending stress or sliding.

In recent years, in electronic devices such as mobile phones, personal computers, cameras, and radio cassettes, the shift to smaller, lighter, and thinner devices has been progressing more and more in response to user requests. For this reason, the printed wiring boards and cables used inside these devices are also compact, lightweight, and thin flexible printed wiring boards (FPC) and flexible flat cables (FFC).

Wiring bodies such as flexible printed wiring boards and flexible flat cables used in these devices must be shielded against external and internal noise. This is because if the signal is not shielded, the signal is affected by noise, the original transmission characteristics are deteriorated, and there is a possibility that a failure may occur in the product.

FIG. 6 is an explanatory view showing a structural example of a conventional flexible printed wiring board (FPC) from an external perspective. The FPC600 here is provided with a base base material 61 formed of animal and plant fibers such as silica, paper, lacquer, and glue, and materials such as biodegradable plastic, flame-retardant polyolefin, and polyester in a thin plate shape, on which the base material 61 is formed. Is provided with a first metal layer 62. The metal layer 62 is a conductor pattern layer 62 on which a conductor pattern (signal pattern) formed by using printing technology or the like is formed. Further, the conductor pattern layer 62 is coated with an insulating coating layer (coverlay) 63 such as polyimide or polyester, and a second metal layer 64 is provided on the insulating coating layer 63.

The second metal layer 64 is an electromagnetic wave shielding layer that shields noise from the outside, that is, a shielding layer 64, and for example, a copper / silver or carbon conductive paste (electromagnetic wave shielding layer) is solidified by using printing technology. After coating or meshing and printing, this can be heat-cured to form. Further, in order to protect the shield layer 64, a protective layer 65 (cover lay) made of polyimide, polyester or the like is provided on the shield layer 64.

In the technical field related to the flexible wiring body including the shield layer as in the present invention, for example, the following patent documents are known.<patcit num="1"><text>Japanese Unexamined Patent Publication No. 2003-168862</text></patcit><patcit num="2"><text>Japanese Patent Application Laid-Open No. 2005-251958</text></patcit>

<p> Here, an example of a shield structure of a flexible printed wiring board (FPC) that has been conventionally used will be specifically described with reference to FIGS. 3 to 5. Figure 3 shows the first example of the shield structure of FPC. FPC300 is a long flat plate-shaped flexible cable with a wiring line (line pattern) LP3 inside, and its central part is slightly constricted. A shielding sheet ST3 such as an aluminum vapor deposition sheet or a copper foil sheet is wrapped around the line pattern to form a shield layer.</p><p> Fig. 4 shows the second example of the shield structure of the FPC. This FPC400 has a flexible flat plate shape in which a line pattern LP4 is installed on the front side and a shield pattern SP4 is installed on the back side. It is a sex cable body, and the shield pattern SP4 here is a shield pattern with a beta land structure. FIG. 5 shows a third example of the shield structure of the FPC. The FPC500 has a flexible flat plate shape in which a line pattern LP5 is installed on the front side and a shield pattern SP5 is installed on the back side. It is a cable body, and the shield pattern SP5 here is a shield pattern with a mesh structure.</p><p> Next, the problems of the shield structure in the conventional FPC will be described. The FPC300 in Fig. 3 requires a separate shielding sheet ST1 such as an aluminum vapor deposition sheet or copper foil sheet that is wrapped around the wiring line, which increases the number of parts and the installation work process. Up becomes a problem. Further, in the FPC 400 in FIG. 4 and the FPC 500 in FIG. 5, a line pattern for shielding a beta clant structure or a mesh structure is provided on the back surface of the wiring line (line pattern) of the FPC, but the line pattern of the double-sided FPC is , It is composed of copper foil and through-hole plating (copper plating). The larger the number of lines and the thicker the lines, the higher the rigidity of the FPC. ) Performance cannot be demonstrated.</p><p> Then, in a flexible cable having a betta clant structure or mesh structure shielding pattern such as FPC400 and FPC500, the wiring pattern is such that the shield patterns are parallel or intersect with respect to the bending direction when bending the flexible cable. Therefore, when bending the FPC, there is a problem that a large force is generated in the direction of being pulled (or contracted) from the pattern, so that the pattern is easily broken.</p><p> The FPC400 in FIG. 4 will be described in more detail. This FPC400 is a long flat plate-shaped flexible cable body consisting of a main part A4-intermediate part B4-main part C4, and the intermediate part B4 is a bent part. When stress is applied in the bending direction (D4 and D4'), it is bent at the bending portion B4, and many bending lines BS4 are generated in the bending portion B4. These bending lines BS4 are formed in the bending direction (D4-D4). It is a line that is orthogonal to or intersects it at an angle. The shield pattern SP4 of this FPC400 is on the outside when bent and has a larger radius of curvature than the line pattern LP4 on the inside, so a larger tensile stress is applied and the shield pattern is likely to break. It has become.</p><p> The present invention has been made in view of the above problems, and is repeated while ensuring a shield structure that does not require a shielding sheet composed of separate parts such as an aluminum vapor deposition sheet and a copper foil sheet, and a reliable shielding property. Flexible wiring with a shield structure that can achieve both shielding and flexibility without easily breaking the shield pattern even when stress is applied due to movements such as bending / twisting / pulling / sliding. The purpose is to provide the body.</p>

<p>(1) In a long flat plate-shaped flexible wiring body in which a line pattern and a shield pattern are wired side by side, the flexible wiring body has a bent portion at a position intersecting the wiring direction of the line pattern, and the bent portion. Has a fold line orthogonal to the fold direction, and the shield pattern is configured to include wiring parallel to the fold line at the fold portion.</p><p>(2) In the flexible wiring body of (1), the shield pattern is configured to include wiring parallel to the bending line and wiring intersecting the bending line at the bent portion. (3) In the flexible wiring body of (2), the shield pattern is formed into a ladder-like pattern by a plurality of wirings parallel to the bending line and at least two wirings orthogonal to the bending line. .. (4) In the flexible wiring body of (1), the shield pattern includes a wiring pattern in the bent portion and a wiring pattern other than the bent portion, and the wiring pattern other than the bent portion is a mesh pattern or a solid pattern. It is composed of a ground pattern.</p>

<p> The flexible wiring body according to the present invention has a bent portion at a position intersecting the wiring direction of the line pattern, the bent portion has a bent line orthogonal to the bent direction, and the shield pattern has a bent portion at the bent portion with the bent line. It is configured with parallel wiring. Therefore, the wiring parallel to the bending line of the shield pattern is not subjected to tensile stress even at the time of bending, and the flexible wiring body itself is not hardened at the time of bending, so that the shielding pattern is less likely to be broken and the shield is shielded. It is possible to provide a flexible wiring body having a shield structure capable of achieving both property and flexibility.</p>

An embodiment of the flexible wiring body according to the present invention will be described with reference to FIGS. 1 (first embodiment) and 2 (second embodiment). Fig. 1 (1) shows the FPC100, which is a long flat plate-shaped flexible cable body consisting of the main part A1-intermediate part B1 (bent part) -main part C1, 3 on the front / side / back (back). It is an external view seen from a direction. In the FPC100, a line pattern LP1 is wired along the longitudinal direction on one surface side (front surface side), and the main part A1 (upper part) and the main part C1 (lower part) pass through the intermediate part B1. It is electrically connected. In addition, the shield pattern SP1 is wired alongside the line pattern LP1 on the other surface side (back surface side), and the main part A1 (upper part) and the main part C1 ((lower part) pass through the intermediate part B1. Is electrically connected.

FIG. 1 (2) is an explanatory diagram showing a state when the FPC 100 of FIG. 1 (1) is bent by applying stress in the bending direction (D1 and D1'). The FPC100 of FIG. 1 (1) is bent at the bending portion B1, but many bending lines BS1 are generated at the bending portion B1, and are these bending lines BS1 orthogonal to the bending direction (D1-D1')? It will be a line that intersects it at an angle. When the shield pattern SP1 of this FPC100 is bent as shown in FIG. 1 (1), it is located on the outside of the bent portion B1 and has a larger radius of curvature than the line pattern LP1 on the inside. It has a structure in which a large tensile stress is easily applied.

In FIG. 1 (1), the wiring structure of the shield pattern SP1 of the FPC100 consists of a large number of horizontal wirings (y1 to y12) parallel to a large number of bending lines BS1 in the bent portion B1 and two vertical wirings (x1) at both ends orthogonal to each other. , X2), and forms a "ladder" as a whole. The vertical wiring (x1, x2) here is the ground line (shield line) arranged substantially parallel to the bending direction (D1 and D1') of the FPC100, and the horizontal wiring (y1 to y12) is the vertical wiring (y1 to y12). It is a ground line (shield line) connecting x1 and x2), and is arranged substantially perpendicular to the bending direction (D1 and D1') of the FPC100.

The wiring of the shield pattern SP1 of FPC100 in FIG. 1 (1) has a bending portion B1 at a position intersecting the wiring direction of the line pattern, and the bending portion B1 has a bending line BS1 orthogonal to the bending direction and shields. The pattern SP1 is configured to include a large number of wirings (horizontal wirings: y1 to y12) parallel to the bending line at the bending portion B1. Therefore, the horizontal wiring (y1 to y12) of the shield pattern SP1 is not subjected to stress in the pulling direction even at the time of bending, and the disconnection of the shield pattern SP1 is less likely to occur. Further, the flexible wiring body (FPC100) itself does not become hard at the time of bending, and the flexible wiring body 100 having a shield structure capable of achieving both shielding property and flexibility can be obtained.

The following FIG. 2 is an external view of the FPC 200, which has a shield structure different from that of the FPC 100, as viewed from the back surface (back surface, shield pattern side). The FPC200 here is the same as the FPC100 in that it is a long flat plate-shaped flexible cable body consisting of the main part A2-intermediate part B2 (bent part) -main part C2, but the back side of this FPC200. Another shield pattern SP2 is wired to, and the main part A2 (upper part) and the main part C2 ((lower part) are electrically connected via the intermediate part B2 (bent part).

In FIG. 2, the wiring of the shield pattern SP2 in the bent portion B2 of the FPC200 is composed of the structure P1 + P2 + P3 in which the patterns P1, P2 and P3 are integrally combined in a flat plate shape, and the pattern P1 And P3 have a shield pattern with the same mesh structure, and pattern P2 has a ladder-like shield structure similar to the shield pattern SP1 in FIG.

The pattern P2 in the center of the folding portion B2 is composed of a plurality of horizontal wirings (y22, y22) parallel to the folding line BS2 and two vertical wirings (x21, x22) at both ends orthogonal to the horizontal wirings (y22, y22). As a whole, it has a low "ladder-like" shield structure. Further, in this FPC200, patterns (P1 and P3) having a conventional shield structure are connected and connected in a plane on both ends (upper and lower parts) of the pattern P2, and the bent portion B2 is substantially bent. When it is not necessary to secure a large area as a part, only the part of the pattern P2 can be formed in a "ladder-shaped" shield structure. Although the shield pattern having a mesh structure is adopted here, a shield pattern having a betta land structure may be used.

So far, we have mainly described examples of applying the flexible wiring body according to the present invention to flexible printed circuit boards (FPCs), but other flexible wiring bodies, such as flexible flat cables (FFC: Flexible Flat), have been mainly described. It can also be applied to Cable).

FIG. 7 is an explanatory view showing a structural example of a flexible flat cable (FFC) from an external perspective. In this FFC700, the conductor pattern 71 is insulated with the insulating coating layer 72 so as to form a flat cable, and then only the insulating coating layer 72 of the ground wire 71G in the conductor pattern 71 is peeled off, and then the acrylic system is used. The electromagnetic wave shielding layer 73 is formed by wrapping it with a copper foil (or an aluminum foil or the like) having a conductive adhesive so as to cover the whole. In the FFC700 with such a structure, the electromagnetic wave shielding layer 73 and the ground wire 71 are strongly connected so that the metal foil for noise blocking does not come off due to stress such as bending or twisting of the cable itself. Need to be raised.

The FPC700 of FIG. 7 is a long flat plate-shaped flexible cable having a line pattern 71 (conductor pattern) in the center and a shield pattern 73 on the surface side. The FPC 700 has a bent portion (not shown) at a position intersecting the wiring direction of the line pattern 71, and the bent portion has a bending line (not shown) orthogonal to the bending direction. Then, if the shield pattern 73 arranged on the surface of the FPC 700 is provided with wiring parallel to the bending line at the bent portion, it is formed as a shield structure similar to the shield pattern of FIG. 1 or FIG. Can be done.

<figref num="1">It is a structural drawing and explanatory drawing which shows the example which applied this invention to the flexible printed wiring board (FPC).</figref><figref num="2">It is a figure which shows another structure when this invention is applied to a flexible printed wiring board (FPC).</figref><figref num="3">It is a figure which shows the 1st example of the conventional shield structure in FPC.</figref><figref num="4">It is a figure which shows the 2nd example of the conventional shield structure in FPC.</figref><figref num="5">It is a figure which shows the 3rd example of the conventional shield structure in FPC.</figref><figref num="6">It is a figure which shows the structural example of the FPC (flexible printed wiring board) to which this invention is applied.</figref><figref num="7">It is a figure which shows the structural example of the FPC (flexible flat cable) to which this invention is applied.</figref>

Code description

100, 200 FPC (Flexible printed wiring board) LP1 Line pattern (Wiring pattern) SP1 Shield pattern (Shielding pattern) A1 Main part A1 (Upper wiring part) B1 Middle part (Bent part) C1 Main part C1 (Lower wiring part) D1 , D1'Bending direction BS1 Bending line y1 ~ y12 Horizontal wiring x1, x2 Vertical wiring P1, P2, P3 Shield pattern y22, y22 Horizontal wiring x21, x22 Vertical wiring 700 FPC (Flexible flat cable) 71 Line pattern (conductor layer) 73 Shield pattern (shield layer)