JP3165141U - Flexible printed wiring board mounting structure - Google Patents

Abstract

A flexible printed wiring board mounting structure capable of reliably preventing peeling of a flexible printed wiring board due to springback at a low cost is provided. A flexible printed wiring board (1) having a structure in which two areas (11, 12) of a flexible printed wiring board (1) are bent at an intermediate area (13) and attached to a body (2) to be mounted. The two regions 11 and 12 of the printed wiring board 1 are attached to one surface 21 and the other surface 22 of the body 2 to be attached to each other with an adhesive, and the intermediate region 13 of the flexible printed wiring board 1 It is positioned in a bent state in the space between the surface 21 and the other surface 22, and an end insertion portion 4 is provided on the other surface 22 of the attached body 2, and the end of the smaller area 12 is provided. Is inserted. [Selection diagram] Fig. 1

Description

  The present invention relates to a flexible printed wiring board mounting structure.

Since the flexible printed wiring board is literally flexible, it can be bent freely. Therefore, flexing the flexible printed wiring board in the free state and attaching it to the housing etc. with adhesive or adhesive on both sides except the freed portion greatly improves the spatial freedom of wiring. In addition, the area and volume required for wiring can be greatly reduced, and the merit of downsizing the equipment is great.
Japanese Patent Laying-Open No. 2003-37375 (Patent Document 1) discloses a foldable electronic device in which a flexible printed board is wound around a rotating shaft and fixed on both sides thereof.

JP 2003-37375 A

However, when the flexible printed wiring board is largely bent and attached to a housing or the like, the attachment may come off due to a restoring force (hereinafter referred to as springback) generated on the bent flexible printed wiring board. Problems arise. Especially when the central part of the flexible printed wiring board is bent in a U-shape or the like with respect to the plate-like part such as a housing and both sides are attached to the front and back of the plate-like part with adhesives in contact with each other. Because the flexible printed wiring board has a large restoring force and uses an adhesive, the flexible printed wiring board once attached is peeled off from the plate-like portion by the spring back at the attachment portion with the smaller contact area. Problems arise.
As a means to prevent the peeling of the adhesive due to the spring back of such a flexible printed wiring board,
First, it is conceivable to improve the components and composition of the pressure-sensitive adhesive and strengthen the adhesive strength. However, the effect of preventing peeling of the flexible printed wiring board is not so great for the cost increase of the adhesive.
Second, it is conceivable to change the insulating base material, copper foil, and coverlay material of the flexible printed wiring board to a more flexible material. However, the effect of preventing the flexible printed wiring board from peeling off is small for the cost increase due to the change of the material used.
Thirdly, there is also a method of suppressing the spring back by bending the bent portion of the flexible printed wiring board many times. However, since the bending process is performed many times, there are problems that man-hours increase and wiring is easily disconnected at the bent portion.

  Therefore, the present invention solves the above-mentioned conventional problems, and even when the flexible printed wiring board is largely bent and attached using an adhesive, it can reliably prevent peeling due to the springback, It is an object of the present invention to provide a flexible printed wiring board mounting structure that can prevent this at a low cost.

The flexible printed wiring board mounting structure of the present invention that solves the above problems is a flexible structure in which two areas of the flexible printed wiring board are bent at the middle area to two different surfaces of the mounted body. A printed wiring board mounting structure,
The two regions of the flexible printed wiring board are attached in contact with one surface and the other surface of the two different surfaces of the attached body, respectively, and an intermediate region of the flexible printed wiring board Is placed in a bent state in a space between one surface of the two different surfaces and the other surface, and the region having the smaller area of the two regions of the flexible printed wiring board is attached The other surface of the body is provided with an end insertion portion that allows insertion of the end portion of the flexible printed wiring board, and the end portion of the smaller area is inserted into the end insertion portion. The first feature is that the smaller region is prevented from being detached by the springback.
In addition to the first feature, the flexible printed wiring board mounting structure of the present invention has a second feature that the end insertion portion is integrally formed as a part of a body to be attached made of resin. Yes.
In addition to the first or second feature, the flexible printed wiring board mounting structure according to the present invention allows the end insertion portion to insert the tip of the smaller area of the flexible printed wiring board. A third feature is that one or more end insertion portions are provided.
In addition to the first or second feature described above, the flexible printed wiring board mounting structure of the present invention allows the end insertion portion to be inserted at both ends of the smaller area of the flexible printed wiring board. The fourth feature is that one or a plurality of pairs are provided as the end insertion portions.
Moreover, in addition to any one of the first to fourth characteristics, the flexible printed wiring board mounting structure of the present invention is such that two different surfaces of the mounted body are front and back surfaces of the same flat plate portion. This is the fifth feature.

According to the flexible printed wiring board mounting structure according to the first feature, the two regions sandwiching the bent intermediate region are respectively adhesive on one surface and the other surface of two different surfaces of the mounted body. Attached to the surface. The intermediate region is positioned in a bent state in the space between the one surface and the other surface. Further, the end of the area having the smaller area is inserted into an end insertion portion provided on the other surface of the attached body. Thus, even when the flexible printed wiring board is bent and attached, it is possible to prevent the flexible printed wiring board from being detached from the attachment surface by the spring back. Moreover, the cost increase which comprises an edge part insertion part does not become so high.
According to the flexible printed wiring board mounting structure according to the second feature, in addition to the function and effect of the first feature, the end insertion portion is integrally formed as a part of the mounted body made of resin. Therefore, dimensional accuracy is ensured, and an appropriate gap and strength for inserting the end can be ensured reliably and easily.
According to the flexible printed wiring board mounting structure according to the third feature, in addition to the operational effects of the first or second feature, the end insertion portion is a region of the smaller area of the flexible printed wiring board. Since one or more end insertion portions that allow the insertion of the tip end portion are provided, it is ensured that the tip end portion of the smaller area of the flexible printed wiring board is detached from the end insertion portion by the spring back. Even when the flexible printed wiring board is bent greatly and attached, large detachment from the attachment surface due to the spring back can be reliably prevented.
According to the mounting structure of the flexible printed wiring board according to the fourth feature, in addition to the function and effect of the first or second feature, the end insertion portion is a region of the smaller area of the flexible printed wiring board. Since one or a plurality of pairs are provided as the end insertion portions that allow the insertion of the end portions on both sides, depending on the placement of the mounted components in the smaller area of the flexible printed wiring board, depending on the tip of the area Even in cases where insertion is hindered, the smaller area of the flexible printed wiring board is supported from both sides to reliably prevent large detachment from the mounting surface of the smaller area due to springback. be able to.
According to the flexible printed wiring board mounting structure according to the fifth feature, in addition to the operational effect of any one of the first to fourth features, two different surfaces of the mounted body are formed of the same flat plate portion. Since it is the front and back surfaces, attach the area with the larger area of the flexible printed wiring board to the front surface (back surface) of the mounted body that is the same single plate, and the intermediate area of the flexible printed wiring board Even when bending (curving) the back side (front side) greatly and attaching the smaller area to the back side (front side), the smaller side area is moved back to the back side (front side) by springback. ) Can be prevented from largely leaving. Thereby, the compact bending attachment of the flexible printed wiring board to the front and back surfaces of the same board can be easily performed in a state where the spring back is prevented.

  According to the flexible printed wiring board mounting structure of the present invention, the flexible printed wiring board is detached from the mounting surface by the spring back even when the flexible printed wiring board is bent largely and attached using an adhesive. Can be reliably prevented, and can be prevented at a low cost.

It is a perspective view explaining 1st Embodiment of the attachment structure of the flexible printed wiring board of this invention. It is sectional drawing explaining 1st Embodiment of the attachment structure of the flexible printed wiring board of this invention. It is a top view which shows the example of the flexible printed wiring board used for the attachment structure of the flexible printed wiring board of this invention. It is a figure which shows the example of the state which attached the double-sided adhesive tape to the back surface of the flexible printed wiring board used for the attachment structure of the flexible printed wiring board of this invention. It is a perspective view which shows the example of the to-be-attached body used for 1st Embodiment of the attachment structure of the flexible printed wiring board of this invention. It is a perspective view explaining 2nd Embodiment of the attachment structure of the flexible printed wiring board of this invention.

  With reference to the following drawings, an embodiment of a flexible printed wiring board mounting structure according to the present invention will be described for the understanding of the present invention. However, the following description is an embodiment of the present invention, and does not limit the contents described in the claims of the utility model registration.

  First, a flexible printed wiring board mounting structure according to a first embodiment of the present invention will be described with reference to FIGS.

  In the flexible printed wiring board mounting structure shown in FIGS. 1 and 2, the flexible printed wiring board 1 is attached to the body 2 to be attached using an adhesive 3. The attached body 2 is provided with an end insertion portion 4 that allows insertion of an end of the flexible printed wiring board 1.

3 and 4, the flexible printed wiring board 1 is composed of polyimide made of an elastic material, other insulating base material 1 a, and conductive material formed on one or both of the front and back surfaces of the base material 1 a. The wiring layer 1b is made of a body. The wiring layer 1b is usually covered with an insulating coating layer.
Since this flexible printed wiring board 1 is excellent in flexibility, it is preferably used in an electronic device or the like that requires a compact configuration, and can be flexibly arranged and attached to form a compact three-dimensional arrangement utilizing space. Can be achieved.
In the present embodiment, a flexible printed wiring board 1 is used in which two regions 11 and 12 are provided on both sides of an intermediate region 13 to be bent.
The two regions 11 and 12 sandwiching the intermediate region 13 are not usually the same in area, and are composed of a region 11 having a larger area and a region 12 having a smaller area. The intermediate region 13 is a region where the space is bent, and is usually configured to be narrower than the region 12 having the smaller area so that the bending in the intermediate region 13 can be easily performed. .
Note that the area 11 having the larger area and the area 12 having the smaller area can be further connected to other areas via the connection area 14. 3 and 4, the area 11 having the larger area continues to the other area via the connection area 14, while the area 12 having the smaller area is the end of the flexible printed wiring board and is connected. The case where there is no area to be shown is shown.

As the substrate 1a, polyimide resin film such as polyamideimide, heat resistant polyester film, polyethylene naphthalate and the like can be used in addition to polyimide. The thickness of the substrate 1a depends on the material, but in the case of the polyimide substrate 1a, the thickness is about 7.5 μm to 25 μm.
Moreover, a copper layer can be used as the wiring layer 1b. However, other conductive materials may be used. The wiring layer 1b may be formed using a copper-clad substrate in which copper is bonded to the surface of the substrate 1a. The thickness of the wiring layer 1b made of copper is usually about 9 μm to 36 μm.
The thickness of the flexible printed wiring board 1 including the polyimide substrate 1a, the copper wiring layer 1b, and the insulating coating layer thereon is about 30 μm to 200 μm.

In the flexible printed wiring board 1, the adhesive 3 is applied to the area 11 having the larger area and the area 12 having the smaller area. On the other hand, it is not necessary to apply the adhesive 3 to the intermediate region 13.
Although the kind of adhesive 3 is not specifically limited, In this embodiment, acrylic is used as the adhesive 3, for example.
In addition, an epoxy or the like can be used as the adhesive 3.
Of course, the adhesive 3 can be non-conductive or conductive. Different pressure-sensitive adhesives 3 can be used for the region 11 having the larger area and the region 12 having the smaller area.

The pressure-sensitive adhesive 3 can be a double-sided pressure-sensitive adhesive tape having release sheets attached to the front and back of the pressure-sensitive adhesive layer. That is, the adhesive 3 is attached to each of the regions 11 and 12 of the flexible printed wiring board 1 by using a double-sided adhesive tape, and the release sheet on one side is peeled off and attached to each of the regions 11 and 12 in a contact state. Do that. In this state, the remaining single-sided release sheet has not yet been peeled off. The remaining single-sided release sheet is peeled off when the flexible printed wiring board 1 is attached to the attached body 2.
The layer thickness of the pressure-sensitive adhesive 3 varies depending on the type of the pressure-sensitive adhesive 3 and is not limited. For example, when the pressure-sensitive adhesive 3 is acrylic or epoxy, the thickness is usually about 25 μm to 200 μm. is there.

Referring also to FIG. 5, the attached body 2 is for attaching the flexible printed wiring board 1. The kind is not particularly limited. However, in reality, mobile phones, other electronic devices, housings of other devices, internal frames, and the like are targeted. Although a resin material that is lightweight and easy to mold is used as a material, a metal material, an inorganic material, or other materials can also be used.
A first surface 21 for attaching the region 11 having the larger area of the flexible printed wiring board 1 in a contact state is formed on the mounted body 2. Moreover, the 2nd surface 22 which attaches the area | region 12 with a smaller area to a contact surface state is comprised. The first surface 21 and the second surface 22 may be configured in the same single attached body 2, or may be configured in a state of being separated into two different attached bodies 2 and 2. it can.
In the present embodiment, as shown in FIG. 5, the first surface 21 and the second surface 22 are the front and back surfaces of the same flat plate portion 2 a of one mounted body 2, that is, the front surface (back surface) and the back surface ( (Surface).
In the space between the first surface 21 and the second surface 22, the intermediate region 13 of the flexible printed wiring board 1 exists, and between the first surface 21 and the second surface 22. The intermediate region 13 is bent in order to absorb the spatial positional deviation.

In the present embodiment, the intermediate region 13 of the flexible printed wiring board 1 extends from the first surface 21 (front surface) of the same flat plate portion 2a of one attached body 2 to the second surface 22 ( It is bent and arranged in a U shape.
That is, in this embodiment, the larger area 11 of the flexible printed wiring board 1 is attached to the first surface 21 of the same flat plate portion 2a of one attached body 2 with the adhesive 3 in a contact state, The intermediate region 13 of the flexible printed wiring board 1 is bent over the end portion 23 of the same flat plate portion 2a in a U shape, and the smaller region 12 of the flexible printed wiring board 1 is the first plate portion 2a of the same flat plate portion 2a. The second surface 22, which is the back surface of the first surface 21, is attached to the second surface 22 with the adhesive 3 in a contact state.

An end insertion portion 4 is provided on the second surface 22 of the body 2 to which the smaller area 12 of the flexible printed wiring board 1 is attached.
The end insertion portion 4 is a member for inserting an end portion of the region 12 having a smaller area of the flexible printed wiring board 1, more specifically, a tip end portion.
The flexible printed wiring board 1 is bent in a U shape in the intermediate region 13, and the first surface 21 and the second surface 22 of the mounted body 2 in the region 11 having the larger area and the region 12 having the smaller area, respectively. When the adhesive 3 is attached to the contact surface, the region 12 having the smaller area is detached from the second surface 22 over time due to the springback phenomenon of the intermediate region 13 and is open. May be. As a method for preventing the mouth opening due to the spring back, it is conceivable to use a material having the adhesive 3 with enhanced adhesive strength, or to weaken the bending restoring force of the flexible printed wiring board 1. However, the strengthening of the adhesive force has a low effect of preventing the detachment for increasing the cost, and the strength of the flexible printed wiring board 1 is reduced when the bending restoring force is weakened.
By providing the end insertion portion 4, it is possible to physically suppress the peeling of the distal end portion of the smaller region 12 that is easily detached from the attached body 2 by the spring back and the accompanying separation. When the end insertion portion 4 is provided, even if the flexible printed wiring board 1 is peeled off due to variations in the environment and conditions of the contact surface mounting work with the adhesive 3, the end insertion portion Since the end portion of the flexible printed wiring board 1 inserted into the end portion 4 is prevented from being detached from the end portion insertion portion 4, further opening of the mouth is reliably prevented.

In the first embodiment, the end insertion portion 4 is configured to insert the tip of the region 12 having the smaller area of the flexible printed wiring board 1 as shown in FIGS. 1 and 5. Yes.
The end insertion portion 4 includes a protruding base portion 4a protruding in the vertical direction from the second surface 22 of the flat plate portion 2a of the mounted body 2, and a side wall portion 4b that is bent from the protruding base portion 4a and extends along the second surface 22. The cross section comprised by these is an L-shaped member.
The end insertion portion 4 can be integrally formed with the flat plate portion 2a when the flat plate portion 2a of the attached body 2 is made of resin. In the first embodiment, the end insertion portion 4 is integrally formed with the resin flat plate portion 2a. When the flat plate portion 2a of the mounted body 2 is made of metal, the end insertion portion 4 can be cut and raised.
The size of the gap S between the end insertion part 4 and the second surface 22 varies depending on the total thickness of the flexible printed wiring board 1 and the adhesive 3. For example, when the total thickness is 150 μm, the gap The dimension of S can be 200 μm to 300 μm. In other words, the gap dimension S, which is increased by about 30% to 100% with respect to the total dimension of the flexible printed wiring board 1 and the adhesive 3, is the end insertion part 4 of the flexible printed wiring board 1. Can be easily inserted, and the flexible printed wiring board 1 can be effectively prevented from escaping from the end insertion portion 4 due to the spring back.
Moreover, the depth D of the edge insertion part 4 is set to 0.5 mm to 2 mm, for example, so that the thickness of the substrate 1 a made of polyimide and the adhesive 3 made of acrylic or epoxy is 30 μm to 200 μm. Thus, escape from the end insertion portion 4 can be effectively prevented.
Further, the width W of the end insertion portion 4 can be set to about 0.5 mm to 20 mm.

Two or more end insertion portions 4 may be provided in parallel with a constant gap.
The side wall portion 4b of the end insertion portion 4 is configured such that the gap S decreases toward the tip, and the side wall portion 4b retains elasticity so that the tip end portion of the flexible printed wiring board 1 is end-capped. When inserting into the part insertion part 4, the side wall part 4b is elastic and the gap S is slightly widened, and the flexible printed wiring board 1 after being inserted is configured to apply a pressing force by elasticity. it can.

A method for producing the flexible printed wiring board according to the first embodiment shown in FIG. 1 will be described. First, a double-sided adhesive tape is attached to the back surface side of the flexible printed wiring board 1 where the wiring layer 1b is not applied. The double-sided pressure-sensitive adhesive tape is attached by removing the release sheet on one side of the double-sided pressure-sensitive adhesive tape, and separating the release sheet into a region 11 having a larger area and a region 12 having a smaller area, which are areas to be attached to the flexible printed wiring board 1. The flexible printed wiring board 1 in the pasted state is prepared. At this time, the double-sided adhesive tape is not attached to the intermediate region 13.
Next, using the prepared flexible printed wiring board 1 with a double-sided pressure-sensitive adhesive tape, the release sheet on the surface of the double-sided pressure-sensitive adhesive tape is peeled off, and the tip of the smaller area 12 is used as the end insertion part 4. In the inserted state, the region 12 having the smaller area is attached to the second surface 22 of the flat plate portion 2a of the mounted body 2 by being attached in a contact state with the double-sided adhesive tape. Further, the end portion 23 of the flat plate portion 2a is bent in a U shape in the intermediate region 13, and the region 11 having the larger area in that state is placed on the first surface 21 of the flat plate portion 2a of the mounted body 2. Attach it with the double-sided adhesive tape. Thereby, the mounting structure of the flexible printed wiring board 1 as shown in FIG. 1 is produced.
In addition, as for the production order, the region 11 having the larger area is pasted to the first surface 21 of the flat plate portion 2a of the mounted body 2 and the end portion 23 of the flat plate portion 2a is attached to the first surface 21 of the flat plate portion 2a. The region 12 having the smaller area is inserted into the end insertion portion 4 and the region 12 having the smaller area is inserted into the second surface 22 of the flat plate portion 2a of the mounted body 2. It is good also as an order stuck on a contact surface state.

FIG. 6 shows a second embodiment of the mounting structure for the flexible printed wiring board 1 of the present invention.
In the first embodiment described above, the mounting structure is such that the tip of the smaller area 12 of the flexible printed wiring board 1 is inserted into the end insertion portion 4, whereas in the second embodiment, The mounting structure is such that both end portions of the area 12 having the smaller area of the flexible printed wiring board 1 are inserted into the end insertion portion 5.
That is, in the second embodiment, the pair of end insertion portions 5 and 5 are provided in a mutually opposed state corresponding to the location where the side end of the region 12 having the smaller area is located. As a result, the end insertion portions 5 and 5 allow a pair of reception of the end portions on both sides of the smaller area 12 of the flexible printed wiring board 1.
The shape of each end insertion portion 5 itself is not particularly different from that of the end insertion portion 4 in the first embodiment, except that the orientation is rotated by 90 degrees.
That is, the end insertion portion 5 includes a protruding base portion 5a protruding in the vertical direction from the second surface 22 of the flat plate portion 2a of the mounted body 2, and a side wall portion that is bent from the protruding base portion 5a and extends along the second surface 22. 5b is a member having a L-shaped cross section.
In the second embodiment, the mounting structure in which both side end portions of the smaller area 12 are inserted into the pair of end insertion portions 5 and 5 is flexible as in the case of the first embodiment. Peeling, detachment, and opening of the printed wiring board 1 from the attached body 2 due to the spring back can be reliably prevented at low cost. In particular, when there is a mounted component near the tip of the smaller area, or when it is necessary to prioritize another configuration, or when the bending of the intermediate region 13 is twisted, that is, the springback is twisted. In some cases, the second embodiment may be effective.
In addition, you may provide the edge part insertion part 5 as multiple pairs.

  In the first embodiment and the second embodiment described above, the case where the flexible printed wiring board 1 is bent and attached to the front and back surfaces of the same flat plate portion has been described. However, when the flexible printed wiring board 1 is bent at the intermediate region 13 between two different flat plate portions of the same mounted body 2, the flexible printed wiring board is further extended between two different mounted bodies 2. The case where 1 is bent and attached in the intermediate region 13 is also within the scope of the flexible printed wiring board mounting structure of the present invention and the manufacturing method thereof.

  The flexible printed wiring board mounting structure of the present invention has high industrial applicability in the field of manufacturing electronic devices including the manufacture of mobile phones.

DESCRIPTION OF SYMBOLS 1 Flexible printed wiring board 1a Base material 11 Area | region with larger area 12 Area | region with smaller area 13 Middle area | region 14 Connection area | region 2a Flat plate part 21 1st surface 22 2nd surface 23 End edge part 3 Adhesive 4 End insertion part 4a Projection base 4b Side wall part 5 End insertion part 5a Projection base part 5b Side wall part S Gap D Depth W Width

Claims (5)

A flexible printed wiring board mounting structure in which two regions of a flexible printed wiring board are bent and attached to an intermediate region on two different surfaces of a mounted body,
The two regions of the flexible printed wiring board are attached in contact with one surface and the other surface of the two different surfaces of the attached body, respectively, and an intermediate region of the flexible printed wiring board Is placed in a bent state in a space between one surface of the two different surfaces and the other surface, and the region having the smaller area of the two regions of the flexible printed wiring board is attached The other surface of the body is provided with an end insertion portion that allows insertion of the end portion of the flexible printed wiring board, and the end portion of the smaller area is inserted into the end insertion portion. A structure for mounting a flexible printed wiring board, characterized in that the smaller area is prevented from being detached by springback.   The flexible printed wiring board mounting structure according to claim 1, wherein the end insertion portion is integrally formed as a part of a mounted body made of resin.   The end portion insertion portion is provided with one or a plurality of end insertion portions that allow insertion of the tip portion of the smaller area of the flexible printed wiring board. Flexible printed wiring board mounting structure.   The end insertion portion is provided with one or a plurality of pairs as end insertion portions that allow insertion of both end portions of the smaller area of the flexible printed wiring board. Mounting structure of the flexible printed wiring board described.   5. The flexible printed wiring board mounting structure according to claim 1, wherein two different surfaces of the mounted body are front and back surfaces of the same flat plate portion.

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