JP4812528B2 - Printed wiring board - Google Patents

Description

  The present invention relates to a printed wiring board in which two rigid boards are connected by a plurality of flexible boards, and the plurality of flexible boards are used as flexible cable portions.

  As this type of conventional printed wiring board, one shown in FIG. 10 is known (see, for example, Patent Document 1). As shown in FIG. 10, in this printed wiring board, the connecting portions of a pair of rigid substrates 101 and 102 are connected to each other on the front side and the back side by flexible substrates 103 and 104, respectively. Here, the two flexible substrates 103 and 104 are separated from each other by the thickness of the rigid substrates 101 and 102. In this connection structure, since the flexible substrates 103 and 104 are connected to the front and back surfaces of the rigid substrates 101 and 102, it is possible to connect many signal lines with a small connection area.

  As shown in FIG. 11, when the rigid substrates 101 and 102 are relatively moved to bend the flexible substrates 103 and 104, a difference between the inner diameter and the outer diameter occurs in the bending, and the flexible substrate 103 on the outer side of the bending is flexible on the inner side of the bending. Interfering with the substrate 104, the flexible substrate 104 inside the bend cannot be deformed into a free bend shape. Therefore, the flexible substrate 104 on the bent side has a bent shape as shown in FIG. 11, and there is a problem that excessive stress concentration occurs at the locations 104 a and 104 b in the vicinity of the connecting portions of the rigid substrates 101 and 102.

As a measure against such a problem, there has been known one provided with a cut-in rigidity suppressing portion in the vicinity of a connecting portion of a rigid substrate of a flexible substrate (for example, see Patent Document 2). However, this method is effective in alleviating the bending stress of the flexible board, but the length of the cable (flexible board) is the same on the inside and outside of the bend, and the inside cable is restricted by the outside cable, making it complicated. There is a problem that it bends. When such complicated bending occurs, there is a problem that the bending life of the flexible substrate is shortened and the wiring circuit is easily disconnected.
JP-A-8-116147 JP2003-101165A

  Accordingly, an object of the present invention is to provide a printed wiring board having a long bending life without stress concentration occurring on the flexible substrate during bending.

The present invention includes two rigid boards arranged at intervals and a plurality of flexible boards respectively connecting the two rigid boards, and by bending the plurality of flexible boards together, A printed wiring board capable of changing a relative position of a rigid board, wherein the plurality of flexible boards are arranged so as to overlap each other, and the flexible boards are connected together on the same one side of the rigid boards. The connection between the flexible substrate and the flexible substrate is soldering or ultrasonic connection between metals .
In the present invention, the plurality of flexible boards are arranged so as to be adjacent to each other in a state before bending, and when the plurality of flexible boards are bent, the flexible boards are positioned on the bending outer side and the bending board. The gist is to suppress the difference between the outer diameter and the inner diameter of the flexible substrate.
In the present invention, among the plurality of flexible substrates, at least one flexible substrate is connected to the rigid substrate on one surface side, and is connected in a state where the other flexible substrate is stacked on the other surface side. This is the summary.
In this invention, it has a connection part in both surfaces of the connection end part of the at least one side in at least one said flexible substrate among these flexible boards, and the said connection of one surface of the said one side connection end part And the connecting portion of the rigid substrate are connected, the connecting portion of the other surface of the connecting end portion on the one side is connected to the connecting portion of the other flexible substrate, and the other flexible substrate is The gist is that it is longer than at least one of the flexible substrates.
In the present invention, the plurality of flexible substrates are arranged so that at least a part thereof overlaps each other, and the flexible substrate that becomes the outside when bent is set to be long in consideration of the thickness of the plurality of flexible substrates. To do.

In the present invention, the apparatus includes two connected flexible boards arranged at intervals, and a plurality of connecting flexible boards that respectively connect the two connected flexible boards. A printed wiring board capable of displacing the relative positions of both of the connected flexible boards by bending the flexible boards together, wherein the plurality of connecting flexible boards are arranged so that at least a part thereof overlaps each other, The connecting flexible substrates are connected together on the same side of each of the connected flexible substrates, and the connection between the connected flexible substrate and the connecting flexible substrate is soldering or ultrasonic connection between metals. This is the gist.

  According to the present invention, a plurality of flexible boards are connected to the same surface of both rigid boards. Therefore, stress concentration due to the difference between the inner diameter and the outer diameter at the time of bending does not occur. Therefore, disconnection of the wiring circuit due to stress concentration at the time of bending can be prevented.

  In addition, according to the present invention, a single-sided substrate in which wiring is formed only on one side can be used as each rigid substrate, so that the cost can be reduced. Thus, since a single-sided board is used and many wirings can be made on one side, the component mounting portion may be a single-sided board, and the cost can be reduced from this point.

  Furthermore, in the present invention, since the thickness of each rigid substrate is not related to the flexibility of the flexible substrate, the rigid substrate can be designed without considering the thickness of each rigid substrate, and the degree of design freedom is increased.

  And according to this invention, after manufacturing each rigid board | substrate and each flexible board | substrate separately, the connection process between both board | substrates should just be performed, Therefore A manufacturing process is simple. Therefore, it is possible to easily redo the connection work of each flexible substrate to each rigid substrate. For the same reason, it is possible to easily change each flexible substrate, so that it is possible to easily cope with a change in the length of each flexible substrate.

  Hereinafter, details of the printed wiring board according to the embodiment of the present invention will be described with reference to the drawings. However, it should be noted that the drawings are schematic, and the thicknesses and ratios of the material layers are different from actual ones. Therefore, specific thicknesses and dimensions should be determined in consideration of the following description. Moreover, the part from which the relationship and ratio of a mutual dimension differ also in between drawings is contained.

(First embodiment)
1 to 3 show a first embodiment of the present invention, FIG. 1 is a side view showing an outline of a printed wiring board, and FIG. 2 is a sectional view showing a state in which the printed wiring board is cut along the longitudinal direction. FIG. 3 is a side view showing a bent state of the printed wiring board.

  As shown in FIGS. 1 and 2, the printed wiring board 1 </ b> A includes first and second rigid boards 10 and 20 that are arranged at intervals, and first and second flexible boards 30 and 40 that connect them. It is composed of

  As shown in FIG. 2, the first rigid substrate 10 includes an insulating substrate (base material) 11, a plurality of wiring patterns 12 patterned on the surface of the insulating substrate 11, and an insulating substrate on which the wiring patterns 12 are formed. And a resist layer (cover layer) 13 provided on the surface of 11 via an adhesive layer (not shown).

  The insulating substrate 11 is made of, for example, glass epoxy, SEM3, paper epoxy, or the like. The wiring pattern 12 is formed by patterning a copper foil attached on the insulating substrate 11 by, for example, a subtractive method. As the adhesive layer (not shown), for example, various resin adhesives such as polyimide, epoxy, and olefin can be used.

  Further, a connection region where the resist layer 13 does not exist is formed on the surface of the insulating substrate 11 of the first rigid substrate 10. In this connection region, two groups of connection terminal portions 12 </ b> A and 12 </ b> B are formed by a part of the plurality of wiring patterns 12. The plurality of first connection terminal portions 12A and the plurality of second connection terminal portions 12B belonging to each group are formed so as to be parallel to each other (sideways).

  Since the configuration of the second rigid substrate 20 is the same as that of the first rigid substrate 10, the same reference numerals are given and description thereof is omitted.

  As shown in FIG. 2, the first flexible substrate 30 has a plurality of wiring patterns 32 formed on one surface of an insulating substrate 31. Then, one end portion of the first flexible substrate 30 is provided so as to expose the same number of connection terminal portions 32A as the plurality of first connection terminal portions 12A of the first rigid substrate 10, and the other end. The same number of connection terminal portions 32B as the plurality of first connection terminals 22A of the second rigid substrate 20 are provided in the portion. A cover layer 33 is formed on the insulating substrate 31 on which the wiring pattern 22 is formed so that only the regions of the connection terminal portions 32A and 32B are exposed. As a constituent material of the insulating substrate 31, for example, polyimide, PEN (polyethylene naphthalate), PET (polyethylene terephthalate), or the like can be used.

  Moreover, since the structure of the 2nd flexible substrate 40 is the same as that of the said 1st flexible substrate 30, the same code | symbol is attached | subjected and the description is abbreviate | omitted.

  Next, the configuration of the connection location between the first and second rigid substrates 10 and 20 and the first and second flexible substrates 30 and 40 will be described.

  The plurality of connection terminal portions 32 </ b> A at one end of the first flexible substrate 30 are soldered to the connection terminal portions corresponding to the first connection terminal portions 12 </ b> A of the first rigid substrate 10, respectively. The plurality of connection terminal portions 32B at the other end of the first flexible substrate 30 are soldered to the connection terminal portions corresponding to the plurality of first connection terminal portions 22A of the second rigid substrate 20, respectively. ing.

  The plurality of connection terminal portions 42A at one end of the second flexible substrate 40 are soldered to the connection terminal portions corresponding to the plurality of second connection terminal portions 12B of the first rigid substrate 10, respectively. . The plurality of connection terminal portions 42B at the other end of the second flexible substrate 40 are soldered to the connection terminal portions corresponding to the plurality of second connection terminal portions 22 of the second rigid substrate 20, respectively. ing.

  As shown in FIGS. 1 and 2, when the first and second rigid substrates 10 and 20 are disposed on the same plane, the first flexible substrate 30 and the second flexible substrate 40 overlap each other at close positions. Has been placed. The first flexible substrate 30 is set to a dimension corresponding to the linear distance between the first connection terminal portions 12A and 22A of the first and second rigid substrates 10 and 20. The second flexible substrate 40 is set to have a dimension slightly longer than the linear distance between the second connection terminal portions 12B and 22B of the first and second rigid substrates 10 and 20. This is to absorb the difference between the outer diameter and the inner diameter between the flexible substrates 30 and 40 caused by the thickness of the second flexible substrate 40 and the first flexible substrate 30 so as not to interfere with each other.

  In the present embodiment, the first and second flexible substrates 30 and 40 are arranged so that the wiring patterns 32 and 42 are facing each other, that is, the insulating substrates 31 and 41 are located outside. .

  In the above configuration, as shown in FIG. 3, the first and second flexible substrates 30 and 40 are bent and bent so that the first and second rigid substrates 10 and 20 are parallel to each other. Then, since the first flexible substrate 30 and the second flexible substrate 40 are connected to the same surface of both the rigid substrates 10 and 20, the flexible substrate 40 positioned on the bent outer side and the flexible substrate 30 positioned on the bent inner side. Since there is almost no difference between the outer diameter and the inner diameter, stress concentration due to the difference between the inner diameter and the outer diameter during bending does not occur. Therefore, disconnection of the wiring circuit due to stress concentration at the time of bending can be prevented.

  Moreover, since single-sided substrates can be used as the rigid substrates 10 and 20, costs can be reduced. Thus, since a single-sided board is used and multilayer wiring can be performed on one side, the component mounting portion may be a single-sided board, and the cost can be reduced from this point.

  Furthermore, since the two first and second flexible substrates 30 and 40 are arranged so as to overlap each other, the total thickness D1 of the first and second flexible substrates 30 and 40 can be reduced. Since the thicknesses of the first and second rigid substrates 10 and 20 are not related to the flexibility of the first and second flexible substrates 30 and 40, the thicknesses of the first and second rigid substrates 10 and 20 are not considered. Rigid board can be designed and design freedom is increased.

  Each of the rigid substrates 10 and 20 is a substrate having first and second connection terminal portions 12A and 12B on its surface, and is first with respect to the first and second connection terminal portions 12A and 12B on the surface. And the printed wiring board 1A can be manufactured by connecting the second flexible boards 30 and 40. Therefore, since each rigid board | substrate 20 and 30 and each flexible board | substrate 30 and 40 are produced separately and the connection process between both board | substrates should just be performed, a manufacturing process is simple. In addition, the connection work of the flexible boards 30 and 40 to the rigid boards 10 and 20 can be easily performed again. For the same reason, the flexible substrates 30 and 40 can be easily changed, so that the length changes of the flexible substrates 30 and 40 can be easily dealt with.

  Furthermore, in the present embodiment, the first and second flexible boards 30 and 40 are arranged so that the wiring patterns 32 and 42 are facing each other, that is, the insulating boards 31 and 41 are located outside. Therefore, when the first and second flexible boards 30 and 40 are bent, the wiring patterns 32 and 42 are located on the inner side of the opposite, so that the degree of deformation can be reduced even in bending in both directions. The durability of 32 and 42 can be improved.

(Concrete example)
Hereinafter, specific materials and dimension examples of the printed wiring board 1A will be described below. The thickness of the insulating substrates 11 and 21 of the rigid substrates 10 and 20 is, for example, 0.4 mm, 0.6 mm, 0.8 mm, 1.0 mm, 1.2 mm, 1.6 mm, 2.0 mm, 2.4 mm, etc. Can be adopted. These insulating substrates 11 and 21 are made of a material such as glass epoxy or SEM-3. Further, the thickness of the insulating substrates 31 and 41 in the first flexible substrates 30 and 40 can be 1/2, 1/3, or 1/4 based on 25 μm. The thickness of the wiring patterns 32 and 42 formed on the insulating substrates 31 and 41 can be ½, ３, ¼, etc. based on 35 μm.

  The wiring patterns 12, 22, 32, and 42 can be a rolled copper foil or an electrolytic copper foil. The width of each of the connection terminal portions 12A, 12B, 22A, 22B, 32A, 32B, 42A, 42B is 10 to 500 μm, and the distance between these connection terminal portions is 10 to 500 μm.

  The distance between the first and second rigid substrates 10 and 20, that is, the actual length of the second flexible substrate 40 is moved to a position where the other is twisted with respect to one of the first and second rigid substrates 10 and 20. When performing such a so-called α winding operation, the length of the bent portion of the second flexible substrate 40 is preferably set to about 30 to 100 mm. Moreover, when arrange | positioning in the place which bends the 1st and 2nd rigid board | substrates 10 and 20 in crank shape, it is preferable to set the length of the bending part of the 2nd flexible substrate 40 to about 5-30 mm. .

  The thickness of the cover layers 33 and 43 is 25 μm or 12 μm. The thickness of the adhesive layer that bonds the cover layers 33 and 43 is, for example, 10 to 30 μm. The present invention is not limited to the materials and dimensions described above.

  In order to manufacture the printed wiring board 1A according to the present embodiment, the connection terminal portions may be soldered in the connection regions of the first and second rigid substrates 10 and 20. At the time of soldering, a solder plating layer is formed on at least one surface of the connection terminal portions, and both ends of the first flexible substrate 30 and the second flexible substrate 40 are not shown heater chips (heating pressure head). ) To apply heat and pressure. In this embodiment, bonding is performed using solder plating. However, in addition to solder plating, bonding using lead-containing solder paste, lead-free solder paste, tin plating, or the like, or metal bonding using ultrasonic waves is performed. You may go.

(Second Embodiment)
4 to 6 show a printed wiring board 1B according to the second embodiment of the present invention. 4 is a side view showing an outline of the printed wiring board, FIG. 5 is a cross-sectional view showing a state cut in the longitudinal direction of the printed wiring board, and FIG. 6 is a side view showing a bent state of the printed wiring board.

  As shown in FIG. 4, the printed wiring board 1 </ b> B includes first and second rigid boards 10 and 20 that are spaced apart from each other, and first, second, and third flexible boards 30, 40 that connect them. 50. That is, the first and second rigid substrates 10 and 20 are connected by the three flexible substrates 30, 40 and 50.

  In addition to the first and second connection terminal portions 12A, 12B, 22A, and 22B, third connection terminal portions 12C and 22C are formed on the first and second rigid substrates 10 and 20, respectively. Then, the connection terminal portions 12A, 12B, 22A, 22B, 12C, and 22C of each group of the first and second rigid substrates 10 and 20 and both sides of the first, second, and third flexible substrates 30, 40, and 50 are provided. The connection terminal portions 32A, 32B, 42A, 42B, 52A, and 52B are soldered together corresponding to each other. The first, second and third flexible boards 30, 40, 50 are arranged so as to overlap each other.

  Since the configuration of the third flexible substrate 50 is the same as the configuration of the first flexible substrate 30 according to the first embodiment, a similar reference numeral is given and description thereof is omitted. Other configurations (including the detailed configuration of each member) are the same as those in the first embodiment, and thus description thereof is omitted to avoid redundant description.

  In the above configuration, as shown in FIG. 6, the first, second and third flexible substrates 30, 40 and 50 are bent and bent so that the first and second rigid substrates 10 and 20 are parallel to each other. . Then, since the 1st flexible substrate 30, the 2nd flexible substrate 40, and the 3rd flexible substrate 50 are connected to the same surface of both the rigid substrates 10 and 20, the flexible substrate 50 located in the bending outer side and the bending middle There is almost no difference between the outer diameter and the inner diameter between the flexible substrate 40 positioned and the flexible substrate 30 positioned inside the bending, and stress concentration due to the difference between the inner diameter and the outer diameter during bending does not occur. Therefore, disconnection of the wiring circuit due to stress concentration at the time of bending can be prevented.

(Third embodiment)
7 to 9 show a third embodiment of the present invention, FIG. 7 is a side view of a printed wiring board, FIG. 8 is a cross-sectional view of a connection portion between the first rigid board and the first and second flexible boards, FIG. 9 is a side view showing a bent state of the printed wiring board.

  As shown in FIGS. 7 to 9, the printed wiring board 1C is similar to the printed wiring board 1A according to the first embodiment, and the first and second rigid boards 10 and 20 are arranged at intervals. And first and second flexible substrates 30 and 40 for connecting them.

  First and second connection terminal portions 12A and 12B are formed on the surfaces of the first and second rigid substrates 10 and 20, respectively. In the third embodiment, both surfaces of the flexible substrate 30 are provided. There are connection terminal portions 32A and 34A. Connection terminals corresponding to each other of the first and second flexible substrates 30 and 40 and the first and second rigid substrates 10 and 20 are connected in a state where the first and second flexible substrates 30 and 40 are overlapped in the connection region. The parts are connected to each other.

  Specifically, the corresponding connecting terminal portions of the first flexible substrate 30 and the first and second rigid substrates 10 and 20 located inside the overlap are directly connected and located outside the overlap. The corresponding terminal portions for connection of the second flexible substrate 40 and the first and second rigid substrates 10 and 20 are connected to each other via the first flexible substrate located inside.

  In the present embodiment, the occupied space on the first and second rigid substrates 10 and 20 necessary for connecting the first and second flexible substrates 30 and 40 can be reduced.

  In the first embodiment, the first and second rigid substrates 10 and 20 are connected via two flexible substrates 30 and 40. In the second embodiment, the first and second rigid substrates 10 and 20 are connected. Although the case where the two rigid boards 10 and 20 are connected via the three flexible boards 30, 40 and 50 has been shown, the two rigid boards 10 and 20 may be connected via four or more flexible boards.

  In the third embodiment, the two flexible boards 30 and 40 are connected to each other on the first and second rigid boards, but the connection is made with three or more flexible boards stacked. You may comprise.

1 is a side view of a printed wiring board according to a first embodiment of the present invention. It is sectional drawing of the printed wiring board concerning the 1st Embodiment of this invention. It is a side view which shows the bending state of the printed wiring board concerning the 1st Embodiment of this invention. It is a side view of the printed wiring board concerning the 2nd Embodiment of this invention. It is sectional drawing of the printed wiring board concerning the 2nd Embodiment of this invention. It is a side view which shows the bending state of the printed wiring board concerning the 2nd Embodiment of this invention. It is a side view of the printed wiring board concerning the 3rd Embodiment of this invention. It is sectional drawing of the connection location of the 1st rigid board | substrate and 1st and 2nd flexible board | substrate of the printed wiring board concerning the 3rd Embodiment of this invention. It is a side view which shows the bending state of the printed wiring board concerning the 3rd Embodiment of this invention. It is sectional drawing of the printed wiring board of a prior art example. It is sectional drawing of the state which bent the printed wiring board of the prior art example.

Explanation of symbols

1A, 1B, 1C Printed wiring board 10 First rigid board 11 Insulating board 12, 13, 22, 23, 32, 42, 52 Wiring pattern 12A, 22A First connection terminal part 13B, 22B Second connection terminal part 12C , 22C Third connection terminal portion 32A, 32B, 42A, 42B, 52A, 52B Connection terminal portion 13, 23 Resist layer 20 Second rigid substrate 21 Insulating substrate 30 First flexible substrate 31, 41, 51 Insulating substrate 33, 43, 53 Cover layer 40 Second flexible substrate 50 Third flexible substrate

Claims (6)

Two rigid boards arranged at intervals, and a plurality of flexible boards respectively connecting the two rigid boards, and bending the plurality of flexible boards together to bend both of the rigid boards A printed wiring board that can displace relative position,
The plurality of flexible boards are arranged so that at least a part thereof overlaps each other, and each flexible board is connected together on the same one side of each rigid board ,
The printed wiring board is characterized in that the connection between the rigid substrate and the flexible substrate is soldering or ultrasonic connection between metals . The plurality of flexible substrates are arranged so as to be adjacent to each other in a state before bending, and when the plurality of flexible substrates are bent, a flexible substrate positioned on the bent outer side and a flexible substrate positioned on the bent inner side, The printed wiring board according to claim 1, wherein a difference between an outer diameter and an inner diameter is suppressed.   Among the plurality of flexible substrates, at least one flexible substrate is connected to the rigid substrate on one surface side and connected in a state where the other flexible substrate is stacked on the other surface side. The printed wiring board according to claim 1. Among the plurality of flexible substrates, at least one of the flexible substrates has a connecting portion on both surfaces of a connecting end portion on at least one side,
The connection portion on one surface of the connection end portion on the one side and the connection portion of the rigid board are connected,
The connection portion on the other surface of the connection end portion on the one side is connected to the connection portion of the other flexible substrate ,
Other of the flexible substrate, printed wiring board according to claim 1, characterized in that longer than at least one of the flexible substrate.   The plurality of flexible substrates are arranged so that at least a part thereof overlaps with each other, and the flexible substrate that becomes the outside when bent is set long in consideration of the thickness of the plurality of flexible substrates. Printed wiring board described in 1. Two connected flexible boards arranged at intervals, and a plurality of connecting flexible boards that connect the two connected flexible boards, respectively, and the plurality of connecting flexible boards are both A printed wiring board capable of displacing the relative positions of both of the connected flexible boards by bending,
The plurality of connecting flexible boards are arranged so that at least a part thereof overlaps each other, and each of the connecting flexible boards is connected together on the same one side of each of the connected flexible boards ,
The printed wiring board is characterized in that the connection between the flexible substrate for connection and the flexible substrate for connection is soldering or ultrasonic connection between metals .

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