JP2010278132A - Flexible wiring board, assembling structure of the same, and electronic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a flexible wiring board in which noise is hardly superimposed on a signal passing through wiring even if the board is used while being folded, to provide an assembling structure of the flexible wiring board, and to provide an electronic apparatus. <P>SOLUTION: A flexible wiring board 15 includes: a base material 31 (a base film); a signal line 32 and a ground layer 33 formed on both faces of the base material 31; and a protective film 38 covering the signal line 32 and the ground layer 33. The signal line 32 and the ground layer 33 are formed on each of routes that are alternately changed between a surface side and a rear surface side of the base material 31 via through holes 34-37, and are mutually formed in faces on opposite sides of the base material 31. The signal line 32 and the ground layer 33 face each other in a portion where faces of the flexible wiring board 15 while being folded face each other. In bent portions R1 and R2, the ground layer 33 is located on the outer peripheral surface side of the base material 31. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a flexible wiring board used by being bent, an assembly structure of the flexible wiring board, and an electronic apparatus.

  As this type of flexible wiring board, for example, Patent Document 1 discloses a method using a microstrip line as a method for reducing noise radiated from the wiring of the flexible wiring board. That is, this flexible wiring board has a structure in which a contactor (wiring) is provided on one surface of a substrate (base material) and a ground is provided on the other surface. In addition, the flexible wiring board is provided with a pattern (recessed portion) that reduces the dielectric loss by deleting the board with a length sufficiently shorter than the signal wavelength, thereby further reducing noise.

  Since the flexible wiring board has flexibility, it is bent and used (for example, Patent Documents 1 to 3).

JP-A-6-334410 JP-A-5-327135 JP 2007-134473 A

  By the way, when the flexible wiring board is bent, the signal lines face each other on the face where the boards face each other. In this state, there is a problem that capacitive coupling occurs between the high-frequency signal transmitted through the signal line of the flexible wiring board and the other signal, and as a result, the high-frequency signal at the rise / fall of the signal is superimposed and becomes noise. It was. Due to these noises, the signal waveform of the signal is different from the waveform to be originally taken, and in some cases, it may cause a malfunction. When the flexible wiring board is bent, the signal line may be close to the signal line of another board or the metal of the housing. In such a case, noise may be superimposed on the signal line.

  Patent Documents 2 and 3 disclose configurations in which a reinforcing plate and a shape holding member are provided on the inner peripheral side of a flexible wiring board that is bent. However, in Patent Document 2, since the reinforcing plate is sandwiched between the circuit component mounting surface and the opposite surface (non-wiring surface), the signal line capacitive coupling does not occur in the first place. Further, in Patent Document 3, the conductor pattern is formed only on one side of the board, and when bent, the shape holding member is provided on the opposite side of the board without the conductor pattern. The configuration was such that no capacitive coupling occurred. In addition, since the shape holding member is only provided at the bent portion, even if the flexible wiring board is bent so that the surface on the conductor pattern side is on the inner peripheral side, and the shape holding member is provided on the inner peripheral side, the shape holding member is bent. In the portions other than the portions, the opposing surfaces are close to each other, and capacitive coupling between the conductor patterns occurs.

  The present invention has been made in order to solve the above-mentioned problems, and an object of the present invention is to provide a flexible wiring board in which noise is not easily superimposed on a signal passing through a wiring, and an assembly structure of the flexible wiring board, and an electronic device. To provide equipment.

  In order to achieve the above object, the present invention provides a flexible wiring board that is used by bending, a flexible base material made of an insulating material, a wiring applied to the base material, and the base material of the wiring. Noise suppression means for suppressing the capacitive coupling of the wiring between the surfaces located between the surfaces facing each other in a state where at least a part is bent on the inner peripheral surface Is the gist.

  According to the present invention, in a state where the base material is bent so that at least a part of the wiring is positioned on the inner peripheral surface, the noise suppression means is located between the opposing surfaces of the base materials, and the noise suppression is performed. By means, capacitive coupling of wiring between the surfaces is suppressed. Therefore, even when the flexible wiring board is bent and used, noise caused by capacitive coupling is hardly superimposed on a signal passing through the wiring.

  In the flexible wiring board of the present invention, the noise suppression means is positioned so that the wiring and the ground layer are opposed to each other on the inner peripheral side where the base material is opposed to each other in a state where the base material is folded. It is preferable to be configured by being formed respectively.

  According to the present invention, in a state where the flexible wiring board is bent, the wiring and the ground layer face each other on the facing surfaces of the substrates. For this reason, since capacitive coupling between the wirings is difficult to occur, for example, even if a signal having a relatively high transmission rate is transmitted through the wirings, it is easy to avoid noise from being superimposed on the signals.

In the flexible wiring board of the present invention, it is preferable that the ground layer is formed on the outer peripheral surface side of the base material at a bent portion formed when the base material is bent.
According to the present invention, the ground layer is located on the outer peripheral surface side of the base material at the bent portion that is formed when the flexible wiring board is bent. For example, when the flexible wiring board is assembled, other electronic components, circuit boards, metal casings (electronic device cases (housings), frames, shielding covers and casings, etc.) Even when the metal is located close to it, the wiring is located on the inner peripheral side of the base material provided with the ground layer on the outer peripheral side at the bent portion, so that the wiring and other electronic components and circuit board side There is no need to worry about capacitive coupling with wiring (for example, signal lines). Even if the metal of the housing is located close to the bent portion, electromagnetic noise generated when static current flows through the metal of the housing is shielded by the ground layer on the outer peripheral surface side of the bent portion. . For this reason, it is difficult for noise to be superimposed on a signal transmitted through the wiring of the flexible wiring board.

  In the flexible wiring board of the present invention, the wiring is formed on the different surfaces of the base material on both sides sandwiching a bent portion formed when the base material is bent in the longitudinal direction of the base material. And a second wiring portion, and a conductive coupling portion that penetrates the base material so as to connect the first wiring portion and the second wiring portion, and the ground layer includes the first wiring portion and the base A first ground layer portion formed on the opposite surface of the material; a second ground layer portion formed on the opposite surface of the second wiring portion and the substrate; the first ground layer portion; It is preferable to include a conductive coupling portion that penetrates the base material so as to connect the second ground layer portion.

  According to this invention, on both sides sandwiching the bent portion in the longitudinal direction of the base material, the first wiring portion and the second wiring portion are located on different surfaces of the base material, and the conductive coupling portions ( For example, they are electrically connected to each other through a through hole or a contact hole. On the other hand, the first ground layer portion located on the surface on the opposite side of the first wiring portion and the base material, and the second ground layer portion located on the surface on the opposite side of the second wiring portion and the base material, respectively, They are located on different surfaces and are electrically connected to each other via a conductive coupling that penetrates the substrate. Therefore, when the flexible wiring board is folded along a virtual line (fold) intersecting with the longitudinal direction (wiring extending direction), the wiring and the ground layer face each other on the folded inner peripheral side. As a result, it is possible to suppress noise from being superimposed on wiring signals. Since the superimposition of noise on the signal can be suppressed in this way, the flexible wiring board can be folded at a fold line that intersects the longitudinal direction (wiring extending direction), and the flexible wiring board can be folded compactly.

  In the flexible wiring board of the present invention, it further has a hollow portion that gives a fold of the bent portion, and the conductive coupling portion is provided at a position shifted from the hollow portion in the longitudinal direction of the base material. Is preferred.

  According to this invention, since the conductive coupling portion is provided at a position shifted from the punched portion that gives the fold of the bent portion in the longitudinal direction of the base material, the base material is at a large angle at the conductive coupling portion. It is easy to avoid bending. Therefore, it becomes easy to avoid the occurrence of poor conduction due to cracking or peeling of the conductive coupling portion that occurs when the base material is bent at a large angle at the conductive coupling portion.

  In the flexible wiring board of the present invention, among the outer surfaces of the two portions positioned on both sides in the overlapping direction in a folded state, the outer surface of the portion on the side where the wiring is positioned outside the base material is provided with a spacing member. Is preferably provided.

  According to the present invention, when the flexible wiring board is folded and assembled, the outer surfaces of the two portions located on both sides in the overlapping direction of the flexible wiring board are peripheral metal members (such as metal casings) and other boards. There is a high possibility of facing. At this time, since the interval holding member is provided on the outer surface of the portion where the wiring is located outside the base material, the wiring and the surrounding metal member (metal The space | interval equivalent to the thickness of a space | interval holding member is ensured between a housing | casing etc. and another board | substrate. As a result, it is possible to suppress the influence of electromagnetic noise generated when static current flows through a metal member on the signal of the wiring, and to suppress the capacitive coupling between the wiring and the wiring on another substrate. Therefore, even when the flexible wiring board is folded, it is difficult for noise to be superimposed on a signal passing through the wiring.

  In the present invention, the wiring is provided on at least one surface of the base material, and the noise suppression means is interposed in a gap between the opposing surfaces of the base material in a state where the base material is folded. It is preferable that it is the space | interval holding member attached to the site | part which can be located.

  According to this invention, in the state in which the flexible wiring board is bent, the spacing member is interposed in the gap between the opposing surfaces of the base materials. Therefore, even if the wirings provided on the opposing surfaces of the substrates face each other, the distance between the wirings is ensured at least equal to the thickness of the spacing member. Therefore, even when the flexible wiring board is bent, the capacitive coupling between the wirings can be kept small, and noise due to the capacitive coupling is hardly superimposed on a signal passing through the wiring.

  The present invention is an assembly structure of a flexible wiring board comprising the flexible wiring board of the invention described above, wherein the flexible wiring board connects two electronic components and is assembled in a folded state. The gist of the invention is that the flexible wiring board is bent so that the ground layer is located opposite to the opposing surfaces of the base materials. According to the present invention, since the wiring and the ground layer are opposed to each other, capacitive coupling between the wirings can be suppressed as in the above-described invention of the flexible wiring board, so that noise is hardly superimposed on a signal transmitted through the wiring.

  The present invention includes the flexible wiring board according to the invention, wherein the flexible wiring board connects the two electronic components in a state where at least one of the two electronic components is at least partially covered by a metal casing. And an assembly structure of a flexible wiring board that is assembled in a state where the wiring and the ground layer are folded so as to be opposed to the opposing surfaces of the base materials. The gist of the invention is that a bent portion in which a ground layer is formed on the outer peripheral surface side of the base material is arranged in a state facing the metal casing among the bent portions formed by folding the wiring board.

  According to this invention, since the ground layer is formed on the outer peripheral surface side of the base material at the bent portion facing the metal housing, the ground layer and the metal housing face each other. Therefore, the signal transmitted through the wiring is not easily affected by electromagnetic noise generated by, for example, static current flowing through the metal housing.

  The present invention comprises the flexible wiring board comprising the flexible wiring board according to the invention, wherein the two electronic parts are connected to each other in a state where at least one of the two electronic parts is at least partially covered by a metal casing. A flexible wiring board assembly structure assembled in a folded state, wherein the wiring is applied to the outer peripheral surface side of the base material in a bent portion formed by bending the flexible wiring board. The gist is that a spacing member is disposed between the outer peripheral surface of the portion and the metal casing facing the outer peripheral surface.

  According to this invention, although the wiring is provided on the outer peripheral surface side of the base material at the bent portion facing the metal casing, the spacing member is interposed between the wiring and the metal casing. Therefore, since a gap equal to or greater than the thickness of the gap holding member is maintained between the wiring and the metal casing, for example, electromagnetic noise generated by a current due to static electricity flowing through the metal casing may be a signal transmitted through the wiring. Hard to overlap.

  The present invention includes the flexible wiring board according to claim 5, wherein the flexible wiring board is in a state where at least one of the two electronic components is at least partially covered by a metal housing. The flexible wiring board is assembled in a state in which the flexible wiring board that is connected is folded, and is formed by folding the flexible wiring board between the opposing surfaces of the flexible wiring board The gist is that a spacing member is interposed between at least one of the bent portion and the metal casing and between the flexible wiring board and the electronic component.

  According to the present invention, in the configuration in which the spacing member is interposed between the surfaces facing the flexible wiring substrate or the configuration in which the spacing member is interposed between the flexible wiring substrate and the electronic component, the surfaces of the substrates facing each other Since capacitive coupling between wirings facing each other is suppressed, it is possible to avoid noise from being superimposed on a signal transmitted through the wiring. In addition, in the configuration in which the spacing member is interposed between the bent portion of the flexible wiring board and the metal casing, electromagnetic noise generated due to, for example, static current flowing in the metal casing is superimposed on the signal transmitted through the wiring. Hateful.

  The gist of the present invention is an electronic device comprising the assembly structure of the flexible wiring board of the present invention. According to this invention, the same effect as the assembly structure of the flexible wiring board can be obtained by the electronic device.

FIG. 3 is a schematic side cross-sectional view showing the assembly structure of the flexible wiring board according to the first embodiment. The schematic sectional side view of a flexible wiring board. The schematic plan view in which the flexible wiring board was partially broken. The perspective view which shows an electronic device. The schematic side view which shows the flexible wiring board in 2nd Embodiment. The schematic sectional side view which shows the assembly structure of a flexible wiring board.

(First embodiment)
Hereinafter, the first embodiment will be described with reference to FIGS. FIG. 4 is a perspective view of the electronic device. As shown in FIG. 4, the electronic device 11 includes a housing 11a, and an electronic unit 12 is built in the housing 11a. The electronic unit 12 includes a main substrate 13 as an electronic component and a hard disk drive (hereinafter referred to as “HDD 14”) as an electronic component disposed on the upper surface of the left end portion of the main substrate 13 in FIG.

  The main board 13 and the HDD 14 are electrically connected via a flexible wiring board 15. The flexible wiring board 15 is folded at two places in the longitudinal direction and is compactly folded in a tri-fold state. A metal casing (hereinafter referred to as “metal casing 16”) is assembled to the main board 13 and the HDD 14 so as to reach the upper surface of the HDD 14 while covering the entire upper surface of the main board 13 (the entire component mounting area). ing. The main board 13 is mounted with various electronic components including a controller that reads / writes data to / from the HDD 14 and a chip component such as a CPU that issues instructions to the controller as necessary. Access to the HDD 14 by the controller is performed via the flexible wiring board 15. At this time, a high-speed signal having a transmission rate of 1.5 Gbps or 3 Gbps is transmitted to the flexible wiring board 15. In addition to the main board 13, a sub board (not shown) and the like are also arranged in the electronic device 11.

  The electronic device 11 according to the present embodiment is an image display device including a display unit (not shown) that can display an image, for example. When an image is displayed on the display unit, the CPU on the main board 13 accesses the HDD 14 via the controller, reads a designated image file, and performs display processing for displaying the read image on the display unit. Of course, the electronic device 11 is not limited to an image display device, and may be a printer, a scanner, a projector, a mobile phone, a PDA (Personal Digital Assistant), a personal computer, or the like.

  FIG. 1 is a schematic cross-sectional side view showing an assembly structure of a flexible wiring board that connects the main board 13 and the HDD 14. As shown in FIG. 1, connectors 17 and 18 are attached to both ends in the longitudinal direction of the flexible wiring board 15. One connector 17 is electrically connected to a connector 19 fixed on the main board 13, and the other connector 18 is electrically connected to a connector 20 provided on the HDD 14 side. As described above, the flexible wiring board 15 is folded at two locations in the longitudinal direction and is compactly folded in a tri-fold state. The assembly structure in which the flexible wiring board 15 is folded contributes to the downsizing of the electronic device 11.

  The metal housing 16 covers the right side portion of the main board 13 in FIG. 1 in a state close to the upper surface, bends upward from the position near the connector 19 and extends to the height of the upper surface of the HDD 14, and then bends toward the HDD 14 side. It extends horizontally and is assembled so as to cover the upper surface of the HDD 14. For this reason, the flexible wiring board 15 is compactly accommodated by being folded in a relatively narrow space surrounded by the main board 13, the HDD 14, and the metal housing 16.

  In addition, a wiring pattern 13a connected to the connector 19 is located at a position below the flexible wiring board 15 on the main board 13, and a wiring pattern 13b connected to another circuit on the main board 13 is located. positioned. The HDD 14 is covered with a metal casing (hereinafter referred to as a metal casing 21), and the connector 20 is exposed from the opening of the metal casing 21. A spacing member 22 is affixed to the upper surface of the flexible wiring board 15 in a folded state. The spacing member 22 of this example is made of an insulating resin sheet, for example.

  Next, the structure of the flexible wiring board 15 will be described in detail with reference to FIGS. FIG. 2 is a schematic side sectional view of the flexible wiring board, and FIG. 3 is a schematic plan view in which the flexible wiring board is partially broken. In FIG. 2, the spacing member 22 is not shown. Further, in FIG. 3, for the sake of convenience of explanation, a schematic diagram with two signal lines is used, but actually, a larger number of signal lines are provided. Moreover, a circuit board may be arrange | positioned at the upper side or the side of the flexible wiring board 15 as needed.

  As shown in FIGS. 2 and 3, the flexible wiring board 15 includes a base material 31 (base film), a signal line 32 as a wiring formed over both surfaces of the base material 31, and a ground layer 33. The base material 31 is made of an insulating material film (for example, a polyimide substrate) and has flexibility. Of course, the substrate 31 may be a fluororesin substrate, a glass substrate bismaleimide triazine resin substrate, a glass substrate epoxy resin substrate, a glass substrate phenol resin substrate, or the like.

  The signal line 32 and the ground layer 33 are made of metal (for example, copper foil). In the present embodiment, the signal line 32 extends along the longitudinal direction of the flexible wiring board 15 (left-right direction in FIG. 3), and is formed on the front surface and the back surface of the base material 31 through the through holes 34 and 35. The wiring paths are alternately switched. On the other hand, the ground layer 33 is formed on a surface opposite to the signal line 32 of both surfaces of the base material 31, and is formed by a path that alternates between the back surface and the front surface through the through holes 36 and 37. That is, the signal line 32 and the ground layer 33 are provided so that the front surface and the back surface of the base material 31 are alternately replaced by a number equal to the number of times of folding. However, since the positions of the through holes 34 and 35 on the signal line 32 side and the through holes 36 and 37 on the ground layer 33 side are slightly shifted in the longitudinal direction of the flexible wiring board 15, the signal line 32 and the ground layer 33 are made of the base material. There are also places on the same side of 31. The wiring includes a power supply line (not shown) in addition to the signal line 32.

  In this example, it is assumed that the flexible wiring board 15 is used by being folded in three (triple) as shown in FIG. 2, and the signal line 32 and the ground layer 33 are folded when the flexible wiring board 15 is folded. Are opposed to each other with two gaps formed between the surfaces facing each other. In addition, the ground layer 33 is formed so as to be positioned on the outer peripheral surface side of the base material 31 at two bent portions formed by bending the flexible wiring board 15. In the present embodiment, the flexible wiring board 15 is folded as shown in FIG. 2, and the signal line 32 and the ground layer 33 are arranged so as to face each other with a gap between the opposing faces. Noise suppression means is configured.

  Here, for convenience of explanation, in a state where the flexible wiring board 15 is folded in three as shown in FIG. 2, the portions extending substantially flat in each of the triple steps are arranged in order from the top to the first flat portion L1 and the first flat portion L1. These will be referred to as “2 flat portion L2” and “third flat portion L3”. Further, the bent portion connecting the first flat portion L1 and the second flat portion L2 is the first bent portion R1, and the bent portion connecting the second flat portion L2 and the third flat portion L3 is the second bent portion. Call it R2. Further, the surface of the flexible wiring board 15 on the upper surface side of the first flat portion L1 in FIG. 2 is referred to as a surface (the lower surface in the second flat portion L2 and the upper surface in the third flat portion L3), and the lower surface side of the first flat portion L1. Is referred to as the back surface (upper surface in the second flat portion L2, and lower surface in the third flat portion L3).

  As shown in FIG. 2, the signal line 32 includes a first signal line 32 </ b> A formed on the surface (upper surface) side of the base material 31 in the first flat portion L <b> 1, a first bent portion R <b> 1, and a second flat portion L <b> 2. A second signal line 32B formed on the back surface (inner surface) of the substrate 31, and a third signal line 32C formed on the surface (inner surface) of the substrate 31 at the second bent portion R2 and the third flat portion L3, It consists of two through holes 34 and 35. The first signal line 32A and the second signal line 32B are conducted through the through hole 34, and the second signal line 32B and the third signal line 32C are conducted through the through hole 35.

  The ground layer 33 is formed on the surface of the substrate 31 by the first ground layer 33A formed on the back surface (inner surface) of the substrate 31 by the first flat portion L1, and by the first bent portion R1 and the second flat portion L2. The second ground layer 33B is formed, the third ground layer 33C is formed on the back surface of the substrate 31 with the second bent portion R2 and the third flat portion L3, and the through holes 36 and 37 are included. The first ground layer 33A and the second ground layer 33B are electrically connected by the through hole 36, and the second ground layer 33B and the third ground layer 33C are electrically connected by the through hole 37.

  Therefore, the signal line 32 passes through the surface of the base material 31 in the first flat portion L1 and reaches the back surface of the base material 31 through the through hole 34, and the inner peripheral surface (back surface) of the base material 31 in the first bent portion R1. ) And the upper surface (back surface) of the substrate 31 at the second flat portion L2. Further, the signal line 32 extends from the upper surface (back surface) of the base material 31 to the lower surface (front surface) of the base material 31 through the through hole 35 at the left end of the second flat portion L2 in FIG. The third flat portion L3 passes through the upper surface (front surface) of the base material 31 while passing through the inner peripheral surface (front surface) of the base material 31.

  On the other hand, the ground layer 33 passes through a surface substantially opposite to the signal line 32 with respect to the base material 31. That is, the ground layer 33 passes through the lower surface (back surface) of the base material 31 in the first flat portion L1 and reaches the surface of the base material 31 through the through hole 36, and the outer peripheral surface of the base material 31 in the first bent portion R1. (Surface) and passes through the lower surface (surface) of the base material 31 at the second flat portion L2. Further, the ground layer 33 extends from the lower surface of the base material 31 to the back surface (upper surface) of the base material 31 through the through hole 37 at the left end portion of the second flat portion L2 in FIG. 2, and the base material 31 at the second bent portion R2. And the third flat portion L3 passes through the lower surface (back surface) of the base material 31.

  In the present embodiment, when focusing on the first flat portion L1 and the second flat portion L2, the first signal line 32A corresponds to the first wiring portion, and the second signal line 32B corresponds to the second wiring portion. The through-hole 34 joining these corresponds to the conductive coupling portion. Further, the first ground layer 33A corresponds to the first ground layer portion, the second ground layer 33B corresponds to the second ground layer portion, and the through-hole 36 joining them corresponds to the conductive coupling portion. On the other hand, when focusing on the second flat portion L2 and the third flat portion L3, the third signal line 32C corresponds to the first wiring portion, the second signal line 32B corresponds to the second wiring portion, and these are joined. The through hole 34 corresponds to the conductive coupling portion. Further, the first ground layer 33A corresponds to the first ground layer portion, the second ground layer 33B corresponds to the second ground layer portion, and the through-hole 36 joining them corresponds to the conductive coupling portion.

  As shown in FIG. 2, the signal line 32 and the ground layer 33 of the flexible wiring board 15 are covered with an electrically insulating protective film 38 made of a photo solder resist film or a coverlay (for example, a polyimide film).

  As shown in FIG. 3, the second ground layer 33 </ b> B formed on the surface side of the base material 31 has a plurality of (3 in this example) extending at both longitudinal ends so as to be connected to the through holes 36 and 37. And the recesses 42 and 42 which are recessed so as to avoid the signal line 32 and the through holes 34 and 35 between the adjacent extension portions 41. The second ground layer 33B is connected to the three through holes 36 via the three extending portions 41 extending to the left end portion in FIG. 3, and via the three extending portions 41 extending to the right end portion in FIG. Are connected to three through holes 37.

  3, the first ground layer 33A is connected to the three through holes 36 at the right end in the longitudinal direction, and the third ground layer 33C is connected to the three ground holes at the left end in the longitudinal direction. It is connected to the through hole 37.

  As for the signal line 32, the first signal line 32A provided on the surface of the base material 31 in FIG. 3 is connected to the through hole 34 located in the recess 42 on the left end side of the second ground layer 33B. . Further, the third signal line 32C provided on the surface of the base material 31 in FIG. 3 is connected to the through hole 35 located in the recess 42 on the right end side of the second ground layer 33B. Further, the second signal line 32B formed on the back surface of the base material 31 in FIG. 3 is connected to the two through holes 36 and 37 at both ends in the longitudinal direction (wiring extending direction).

  Further, as shown in FIG. 2, the first bent portion R1 and the second bent portion R2 have a concave portion 43 as a hollow portion formed by removing a part of the ground layer 33 at a substantially central position in the longitudinal direction. Is provided. The recess 43 is formed by removing the copper foil by etching in the pattern formation process of the ground layer 33. As shown in FIG. 3, a plurality of recesses 43 are provided at intervals in the width direction of the base material 31 (the vertical direction in FIG. 3). When the flexible wiring board 15 is bent, the concave portion 43 tends to be a crease between the bent portions R1 and R2.

  The through holes 34 to 37 are formed at positions shifted in the longitudinal direction of the base material 31 from the positions at which the concave portions 43 are formed. For this reason, the formation of the through holes 34 to 37 is prevented from being a fold. For this reason, it is easy to avoid poor conduction due to the through holes 34 to 37 being bent at a relatively tight angle to induce, for example, cracks and peeling. In addition, although the recessed part 43 was formed in 1 row in the width direction of the base material 31, the pattern shape can be changed suitably, for example, may be arranged in multiple rows or may be given in mesh shape. The pattern formation of the signal line 32, the ground layer 33, the concave portion 43, and the like is not limited to a method using exposure, development, etching, or the like, and at least some of them may be formed by laser processing.

  As shown in FIG. 1, the flexible wiring board 15 configured in this way has connectors 17 and 18 at both ends in the longitudinal direction connected to a connector 19 on the main board 13 side and a connector 20 on the HDD 14 side, respectively. And it is assembled in a folded state in three.

  In a state where the flexible wiring board 15 is folded, as shown in FIGS. 1 and 2, the lower surface of the first flat portion L1 and the upper surface of the second flat portion L2 face each other. As a result, the first ground layer 33A applied to the lower surface of the base material 31 at the first flat portion L1 and the second signal line 32B applied to the upper surface of the base material 31 at the second flat portion L2 face each other. Further, the lower surface of the second flat portion L2 and the upper surface of the third flat portion L3 face each other. As a result, the second ground layer 33B applied to the lower surface of the base material 31 at the second flat portion L2 and the third signal line 32C applied to the upper surface of the base material 31 at the third flat portion L3 face each other. For this reason, in the folded state, there is almost no portion where the signal lines 32 face each other, so that it is possible to suppress noise superposition due to capacitive coupling between the opposed signal lines.

  Further, as shown in FIG. 1, in the first bent portion R <b> 1 of the flexible wiring substrate 15, the ground layer 33 (second ground layer 33 </ b> B) provided on the outer peripheral surface side of the base material 31 faces the metal housing 16. is doing. Further, in the second bent portion R <b> 2 of the flexible wiring substrate 15, the ground layer 33 (third ground layer 33 </ b> C) provided on the outer peripheral surface side of the base material 31 faces the metal housing 21. Therefore, even if electromagnetic current flows through the metal housings 16 and 21 and electromagnetic field noise is generated, the electromagnetic field noise is shielded by the ground layer 33, so that superposition of electromagnetic noise on the high-frequency signal of the signal line 32 is suppressed. can do.

As described above in detail, according to the present embodiment, the following effects can be obtained.
(1) In a state where the flexible wiring board 15 is folded, the signal line 32 and the ground layer 33 face each other with a gap between the opposing faces. For this reason, since the signal lines 32 do not face each other in the folded state, capacitive coupling between the signal lines hardly occurs. Therefore, it is possible to suppress noise due to capacitive coupling between the signal lines from being superimposed on the high-frequency signal of the signal line 32.

  (2) In the two bent portions R1 and R2 of the flexible wiring board 15, the ground layer 33 is disposed on the outer peripheral surface side of the base material 31, and the ground layer 33 is opposed to the metal casings 16 and 21. Therefore, even when current due to static electricity flows through the metal housings 16 and 21 and electromagnetic noise is generated, it is possible to suppress the electromagnetic field noise from being superimposed on the high-frequency signal of the signal line 32.

  (3) The first signal line 32A (or the third signal line 32C) and the second signal line formed on different surfaces of the base material 31 on both sides in the longitudinal direction of the base material 31 across the bent portion R1 (or R2). 32B was connected through the through hole 34 (or 35). Also, the first signal layer 32A (or the third signal line 32C) and the first ground layer 33A (or the third ground layer 33C) formed on the opposite surface of the base material 31, the second signal line 32B, and the base The second ground layer 33B formed on the opposite surface of the material 31 was connected via a through hole 36 (or 37). Therefore, when the flexible wiring board 15 is bent along a virtual line (fold) intersecting with the longitudinal direction (signal line extending direction), the signal line 32 and the ground layer 33 face each other on the opposing surface, and the signal line The superimposition of noise on 32 high frequency signals can be suppressed. Since the superimposition of noise on the high-frequency signal can be suppressed in this way, the flexible wiring board 15 can be folded at a fold that intersects with the longitudinal direction, and the flexible wiring board 15 can be folded effectively and compactly. For example, when a flexible wiring board is folded along a virtual line (fold) that intersects the width direction (short direction), it is necessary to have a storage space that can accommodate a length equal to the total length, no matter how many times it is folded. Become. On the other hand, since the flexible wiring board 15 can be folded at a fold line that intersects the longitudinal direction, the maximum length can be shortened according to the number of folding, and the flexible wiring board 15 can be stored compactly.

  (4) Since the through holes 34 to 37 are arranged at positions deviating from the concave portion 43 serving as the folds of the bent portions R1 and R2 in the longitudinal direction (wiring extending direction) of the substrate 31, portions of the through holes 34 to 37 It is easy to avoid bending at a large angle. Therefore, the through holes 34 to 37 are bent at a large angle, so that the through holes 34 to 37 are cracked, peeled off, and the like, and it is easy to prevent a conduction failure caused by the crack. For this reason, the lifetime of the flexible wiring board 15 and the improvement of the reliability can be realized for the structure using the through holes 34 to 37.

  (5) Of the outer surfaces of the portions (the upper surface of the first flat portion L1 and the third flat portion L3) located on both sides in the overlapping direction of the flexible wiring board 15, the outer surface where the signal line 32 is positioned outside the base material 31 The spacing member 22 was attached to the upper surface of a certain first flat portion L1. Therefore, even if the signal line 32 (32A) located outside the base material 31 faces the metal casing 16, the signal line 32 and the metal casing 16 are interposed by the spacing member 22 interposed therebetween. A relatively wide distance can be maintained between the two. For this reason, it can suppress that the electromagnetic noise which generate | occur | produced when the electric current by static electricity flows into the metal housing | casing 16 is superimposed on the high frequency signal of the signal wire | line 32 (1st signal wire | line 22A).

(Second Embodiment)
Next, a second embodiment will be described with reference to FIGS. FIG. 5 is a schematic side view showing a state in which the flexible wiring board is straightened, and FIG. 6 is a side sectional view showing the assembly structure of the flexible wiring board.

  As shown in FIG. 6, the configuration of the electronic device 11 is the same as that of the first embodiment, and the electronic unit 12 is built in the housing 11a. The configuration of the electronic unit 12 includes the main board 13, the HDD 14, the flexible wiring board 50, the metal housing 16, and the like, and the flexible wiring board 50 and its assembly structure are different from those in the first embodiment. .

  As shown in FIG. 5, the flexible wiring board 50 is folded three times, and the connector 17 fixed to one end in the longitudinal direction is connected to the connector 19 on the main board 13 side and fixed to the other end. When the connector 18 is connected to the connector 20 on the HDD 14 side, the connectors 18 are assembled in an electrically connected state.

  A spacing member 51 and a spacing member 52 are respectively attached to the flexible wiring board 50 at positions that can be respectively interposed in gaps between two sets of opposing surfaces formed when folded. Further, a spacing member 53 is interposed between the folded portion of the flexible wiring board 50 and the main board 13 (wiring patterns 13a and 13b). These spacing members 51 to 53 are made of an electrically insulating material (for example, insulating synthetic resin), and are fixed at predetermined positions where the flexible wiring board 50 can be interposed as described above. As the fixing method, an appropriate method such as adhesion or adhesion using an adhesive or the like can be employed. In the present embodiment, the noise suppressing means is configured by the interval holding member 51 interposed in the gap where the signal lines 62 face each other.

  As shown in FIGS. 5 and 6, in the flexible wiring board 50 of the present embodiment, the signal line 62 is applied to one surface (back surface) of the base material 61, and the other surface (front surface) of the base material 61 is grounded. Layer 63 is applied. The signal line 62 and the ground layer 63 are covered with an insulating protective film 38 except for the connection portion between the connectors 17 and 18.

  A spacing member 51 is fixed to the lower surface (back surface) of the portion of the flexible wiring board 50 that is closer to one end in the longitudinal direction (closer to the left end in FIG. 5). In addition, a gap holding member 52 is fixed to the upper surface (front surface) and a gap holding member 53 is fixed to the lower surface (back surface) of the flexible wiring board 50 near the other end (right edge in FIG. 5). Yes. The length in the longitudinal direction (wiring extending direction) of these spacing members 51 to 53 is slightly shorter than the length of one layer of the flat portions L1, L2, and L3 as shown in FIG. Therefore, the interval holding members 51 and 52 are interposed in a range covering almost the entire area of the opposing surface of the flexible wiring board 50, and the interval holding members 51 and 52 are fixed at a slightly reserved position that does not reach the bent portions R1 and R2. Therefore, it does not hinder the formation of the bent portions R1, R2. In addition, as shown in FIG. 6, the recessed parts 64 and 65 which make a crease easy are formed in the longitudinal direction center part of bending part R1, R2. These recesses 64 and 65 are formed by partially removing the ground layer 63 by etching or the like.

  Further, as shown in FIG. 6, a spacing member 54 is provided between the metal housing 21 and the bent portion R <b> 2 where the signal line 62 is located on the outer peripheral surface side of the base member 61 among the bent portions R <b> 1 and R <b> 2. Intervene. The spacing member 54 is made of, for example, an electrically insulating synthetic resin sheet, and is fixed to the side surface of the metal casing 21.

  According to the second embodiment, in a state where the flexible wiring board 50 is folded, the signal lines 62 face each other at the portion where the first flat portion L1 and the second flat portion L2 face each other. A spacing member 51 is interposed in the gap between the surfaces. As a result, since the interval between the signal lines 62 is maintained at a certain value or more, capacitive coupling between the signal lines 62 is suppressed. For this reason, the distance between the signal line 62 and the wiring patterns 13a and 13b is maintained at a value equal to or greater than a certain value, and capacitive coupling between the signal lines 62 is suppressed. Therefore, it is possible to suppress noise due to capacitive coupling between the signal lines 62 from being superimposed on the high-frequency signal of the signal line 62.

  In addition, a spacing member 53 is interposed between the main substrate 13 and the outer surface on the side where the signal line 62 is positioned outside the base member 61 among the outer surfaces on both sides in the overlapping direction of the flexible wiring substrate 50. That is, the spacing member 53 is interposed between the wiring patterns 13 a and 13 b on the main board 13 and the flexible wiring board 50. As a result, since the distance between the signal line 62 and the wiring patterns 13a and 13b is maintained at a certain value or more, capacitive coupling between the signal line 62 and the wiring patterns 13a and 13b is suppressed. Therefore, it is possible to suppress the noise due to capacitive coupling between the signal line 62 and the wiring patterns 13a and 13b from being superimposed on the high-frequency signal of the signal line 62.

  Further, a spacing member 54 is interposed between the bent portion R2 and the metal casing 21. The spacing member 54 is made of, for example, an electrically insulating synthetic resin sheet, and is fixed to the side surface of the metal casing 21. As a result, since the distance between the signal line 62 and the metal casing 21 is maintained at a certain value or more, electromagnetic noise generated when a current due to static electricity flows through the metal casing 21 is caused by the high-frequency signal of the signal line 62. It can suppress that it superimposes on.

The said embodiment is not limited above, It can also change into the following aspects.
(Modification 1) In the first embodiment, the ground layer is formed on the outer peripheral surface side of the substrate at all the bent portions, but the ground layer is formed on the outer peripheral surface side of the substrate at at least one bent portion. If it is enough. In this case, the ground layer should just be formed in the outer peripheral surface side of a base material in the bending part which opposes a metal housing | casing.

  (Modification 2) In each of the above embodiments, the spacing member is attached to the metal housing side, but the spacing member may be attached to the outer peripheral surface of the bent portion. Furthermore, the spacing member may be disposed between the metal casing and the outer peripheral surface of the bent portion, and may be supported by, for example, a bracket or supported on the main board 13.

(Modification 3) In the first embodiment, a configuration in which the outer peripheral surface side of the base material of the bent portion is a wiring (signal line) and a spacing member is disposed between the bent portion and the metal housing can be employed.
(Modification 4) The spacing member is not limited to being made of an electrically insulating material such as synthetic resin. The spacing member may be an electromagnetic shielding material (conductive material).

  (Modification 5) In the second embodiment, all of the surfaces between the flexible wiring boards, between the bent portion of the flexible wiring board and the metal housing, and between the flexible wiring board and the electronic component (board 13) are all used. In addition, although the spacing member is interposed, at least one of the spacing members may be interposed. However, it is desirable to interpose a spacing member between the surfaces of the flexible wiring board where the signal lines face each other. For example, the present invention may be applied to an assembly structure in which the metal casing is not near the flexible wiring board. In this case, it is only necessary that a spacing member is interposed between the surfaces facing the flexible wiring board.

  (Modification 6) The folding form of the flexible wiring board is not limited to the triple folded state. You may fold and use it double, quadruple, and fivefold. Further, the folding method may be such that the layers are not completely overlapped, but the flexible wiring board is folded with the layers slightly shifted.

  (Modification 7) In each of the above embodiments, for example, a flexible wiring board manufactured by using a double-sided copper-clad laminate and having a wiring and a ground layer on both sides of the substrate is employed. You may employ | adopt the flexible wiring board with which wiring and the ground layer were given only to the single side | surface of the base material manufactured using the board. Even in this configuration, wiring is performed in a wiring path in which the wirings do not face each other in a state where the flexible wiring boards are folded, and a spacing member is interposed on the surface where the bases face each other. In other words, it is possible to suppress noise due to capacitive coupling between distributions between the planes from being superimposed on a signal transmitted through the wiring.

  (Modification 8) The two electronic components are not limited to the main board and the HDD. For example, in a printer, a substrate and a recording head may be used. In addition, the two electronic components may be two substrates, a substrate and a mounting component on the substrate, or between two components mounted on the substrate.

The technical idea grasped from the embodiment and the modified examples will be described below.
(1) A flexible wiring board used by bending, comprising: a flexible base made of an insulating material; a wiring applied to the base; and a ground layer applied to the base; The flexible printed circuit board according to claim 1, wherein the ground layer is formed on each of the opposing surfaces of the base material in a state where the base material is bent.

  DESCRIPTION OF SYMBOLS 11 ... Electronic device, 11a ... Housing, 12 ... Electronic unit, 13 ... Main board as electronic component, 14 ... HDD as electronic component, 15 ... Flexible wiring board, 16 ... Metal housing, 17 ... Connector (flexible wiring board) Side), 18 ... connector (flexible wiring board side), 19 ... connector (main board side), 20 ... connector (HDD side), 21 ... metal casing, 22 ... spacing member, 31 ... base material, 32 ... wiring 32A, a first signal line as a first wiring part, 32B, a second signal line as a second wiring part, 32C, a third signal line as a first wiring part, 33, a ground layer, 33A. ... a first ground layer as a first ground layer part, 33B ... a second ground layer as a second ground layer part, 33C ... a third ground layer as a first ground layer part, 4, 35... Through hole (signal line side) as a conductive coupling portion, 36, 37... Through hole (ground layer side) as a conductive coupling portion, 38... Protective film, 41. ... Recessed portion as hollow portion, 50... Flexible wiring board, 51. Space holding member as noise suppressing means, 52 to 54. Space holding member, 61. Base material, 62 ... Signal line, 63 ... Ground layer, 64. 65: concave portion, L1: first flat portion, L2: second flat portion, L3: third flat portion, R1: first bent portion as a bent portion, R2: second bent portion as a bent portion.

Claims (12)

A flexible wiring board used by bending,
A flexible base made of insulating material;
Wiring applied to the substrate;
Noise that suppresses capacitive coupling of the wiring between the surfaces, which is located between the opposing surfaces of the substrates in a state where the substrate is bent so that at least a part of the wiring is located on the inner peripheral surface A flexible wiring board comprising a suppression means.   The noise suppression means is formed such that the wiring and the ground layer are opposed to each other on the folded inner peripheral side on the opposed surfaces of the substrates in a state where the substrates are folded. The flexible wiring board according to claim 1, wherein the flexible wiring board is configured by being attached.   The flexible wiring board according to claim 2, wherein the ground layer is formed on an outer peripheral surface side of the base material at a bent portion formed when the base material is bent. The wiring includes a first wiring portion and a second wiring portion that are formed on different surfaces of the base material on both sides of a bending portion formed when the base material is bent and sandwiched in the longitudinal direction of the base material. A conductive coupling portion penetrating the base material so as to connect the first wiring portion and the second wiring portion;
The ground layer includes a first ground layer portion formed on a surface opposite to the first wiring portion and the base material, and a second ground layer formed on a surface opposite to the second wiring portion and the base material. The flexible layer according to claim 2, further comprising: a ground layer portion; and a conductive coupling portion penetrating the base material so as to connect the first ground layer portion and the second ground layer portion. Wiring board.   5. The method according to claim 4, further comprising a hollow portion for providing a crease of the bent portion, wherein the conductive coupling portion is provided at a position shifted from the hollow portion in the longitudinal direction of the base material. The flexible wiring board as described.   Of the outer surfaces of the two portions positioned on both sides in the overlapping direction in the folded state, a spacing member is provided on the outer surface of the portion on the side where the wiring is positioned outside the base material. The flexible wiring board according to any one of claims 1 to 5. The wiring is applied to at least one surface of the substrate;
The said noise suppression means is a space | interval holding member attached to the site | part which can be located in the clearance gap between the surfaces which the said base materials oppose in the state which bent the said base material. A flexible wiring board according to 1. An assembly structure of a flexible wiring board comprising the flexible wiring board according to any one of claims 2 to 6, wherein the flexible wiring board connects two electronic components and is assembled in a bent state. Because
The assembly structure of a flexible wiring board, wherein the flexible wiring board is bent so that the wiring and the ground layer are positioned so as to face each other of the opposing surfaces of the base materials. The flexible wiring board according to any one of claims 3 to 6, wherein the flexible wiring board is in a state where at least one of two electronic components is at least partially covered by a metal casing. Assembly of a flexible wiring board that connects two electronic components and is assembled in a state where the wiring and the ground layer are folded so as to be opposed to the opposing surfaces of the base materials Structure,
Of the bent portions formed by folding the flexible wiring board, a bent portion in which a ground layer is formed on the outer peripheral surface side of the base material is disposed in a state facing the metal casing. Wiring board assembly structure. The flexible wiring board according to any one of claims 2, 4, 5, 6 to 7, wherein at least one of the two electronic components is at least partially covered by a metal casing. A flexible wiring board assembly structure in which the flexible wiring board that connects two electronic components is assembled in a folded state,
Among the bent portions formed by bending the flexible wiring board, between the outer peripheral surface of the bent portion where the wiring is applied to the outer peripheral surface side of the base material and the metal casing facing the outer peripheral surface Is an assembly structure of a flexible wiring board, characterized in that a spacing member is disposed. The flexible wiring board according to claim 7, wherein the flexible wiring board connects the two electronic components in a state where at least one of the two electronic components is at least partially covered by a metal housing. The flexible wiring board is assembled in a state where the flexible wiring board is folded,
Between the surfaces facing the flexible wiring board, between the bent portion formed by folding the flexible wiring board and the metal housing, between at least one of the flexible wiring board and the electronic component. An assembly structure of a flexible wiring board, characterized in that a spacing member is interposed.   The electronic device provided with the assembly | attachment structure of the flexible wiring board as described in any one of Claims 8 thru | or 11.

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