JP2006324406A - Flexible/rigid multilayer printed circuit board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a flexible/rigid multilayer printed circuit board which is improved in incorporating workability and effectively prevented from being disconnected by an improvement in durability while it is bent through a process of restraining the action of a very high restoring force caused by a compressive stress and a tensile stress generated at an FPC part composed of three FPC boards. <P>SOLUTION: Multilayered boards 2 and 3 equipped with a first to a third conductor layer 2a, 3a, 2b, 3b, and 2c and 3c, are electrically connected together with a flexible FPC 4 for the formation of flexible/rigid multilayer printed circuit board A, and the FPC is composed of the first to the third FPC board, 4a, 4b and 4c, which electrically connect the conductor layers of the multilayered board parts 2 and 3 separately. The extensional lengths of the FPC boards 4a, 4b and 4c led out separately from the conductor layers are set in such a manner that the external second FPC is extended longer than the internal third FPC board, when the FPC is bent and that the external first FPC board is extended longer than the internal second FPC board so as to make them different. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a flex-rigid multilayer wiring board in which multilayer substrate portions are electrically connected to each other by an FPC portion, and more specifically, as a measure for improving durability when bending an FPC portion composed of a plurality of plates. Involved.

  Conventionally, this type of flex-rigid multi-layer wiring board is formed by electrically connecting multi-layer substrate portions each having a plurality of conductor layers formed by etching or the like through flexible FPC portions. A substrate in which substrate portions and an FPC portion are integrally formed is known (for example, see Patent Document 1).

  By the way, the flex-rigid multilayer wiring board can be used for three-dimensional high-density mounting by mounting components in a flat state and bending the FPC part when mounting in a device. It is possible to contribute to the transformation. In that case, when the flex-rigid multi-layer wiring board is incorporated into a device and then repeatedly bent and stretched at a bent portion such as a hinge portion of a mobile phone, the FPC portion connecting the multi-layer substrate portions is electrically connected. In many cases, it is used to be bent repeatedly while serving as a cable for securing the cable.

Then, as shown in FIG. 13, the flex-rigid multilayer wiring board has an FPC at a hinge portion of a cellular phone when the multilayer substrate portions a1 and a2 are connected to each other by an FPC portion b made of a single plate b1. Even if the portion b is repeatedly bent, it can serve as a cable that ensures electrical continuity. On the other hand, as shown in FIGS. 14 and 15, the multilayer substrate portions c1 and c2 or e1 , E2 are electrically connected independently for each conductor layer, and the FPC portion d or f is composed of a plurality of plates d1, d2 or f1 to f3. If the FPC portion b has the same number of wires as compared to the structure of the single plate b1 by adopting a configuration consisting of a plurality of plates d1, d2 or f1-f3. Since the number of wirings per plate of the PC part d or f can be reduced, the double-sided structure can be made into a single-sided structure, and the thickness per board of the FPC part d or f can also be reduced, bending performance, flexibility, The durability during repeated bending can be improved.
JP-A-11-68312

  By the way, the flex-rigid multi-layer wiring board is used so that the FPC part is bent in some bending state or is repeatedly bent in the state where it is incorporated like a hinge part of a mobile phone when it is incorporated into a device as described above. There are many things to do.

  In that case, there is a high demand for an increase in the number of circuits that pass through the FPC part due to higher functionality of the device, and it is difficult to accommodate the required number of circuits if the FPC part is composed of a single plate. It has become indispensable to configure the FPC portion with a plurality of plates. In addition, it is known that the durability when repeatedly bending is higher when the FPC portion is composed of two single-sided plates than when the single-sided double-sided plate is used. For this reason, there are situations in which it is indispensable to configure the FPC portion with a plurality of sheets.

  However, as shown in FIG. 13, in the case where the FPC portion b electrically connecting the multilayer substrate portions a1 and a2 is composed of one plate b1, the FPC portion b is freely deformed when bent. As shown in FIG. 14, the FPC portion d that electrically connects the multilayer substrate portions c1 and c2 is composed of two plates d1 and d2, and as shown in FIG. In the case where the FPC portion f that electrically connects the substrate portions e1 and e2 is constituted by the three plates f1, f2, and f3, the plates d1, d2, and f1 to f3 of the respective FPC portions d and f. Since the length and shape are the same, and the positions where the plates d1, d2, f1 to f3 derived from the multilayer substrate portions c1, c2, e1, and e2 are derived are also the same position, the multilayer substrate portions c1, c2, and e1 , E When incorporating each other FPC portion d, the device is bent at f, FPC portion d, f (bent portion) in a plurality of plate d1, d2, overlap f1~f3 are interfering with each other. This is because the bending radii of the plates d2, f2 (or f3) located on the inner side when bent and the plates d1, f1 (or f2) located on the outer side are different, and ideally the outer side when bent. In the case of a flex-rigid multilayer wiring board obtained by a known manufacturing method, the length of the board d1, f1 (or f2) located at the position should be longer than the length of the board d2, f2 (or f3) located inside. Since the plurality of plates d1, d2, f1 to f3 constituting the portions d and f are all the same length and the same shape, the plates d2 and f2 (or f3) positioned inside when bent are ideal. This is because the plates d1, f1 (or f2) located outside and longer than the ideal length are shorter than the ideal length.

  Therefore, as shown in FIG. 16, in the bent state, a compressive stress is generated in the plate d2 positioned on the inner side to cause slackening, and a tensile stress is generated on the plate d1 positioned on the outer side to exert a strong tension. In such a state, the restoring force to return the bent part to its original state acts remarkably, and the FPC part (bent part) tries to return to its original shape when assembling into the device, and the workability of the incorporation is reduced. Cause damage. In addition, since tensile stress or compressive stress is applied to the outer plate d1 and the inner plate d2 bent at the time of incorporation, if it is used repeatedly, it will be bent due to excessive stress applied to the circuit pattern. The durability at the time is significantly reduced, and the FPC portion b is freely deformed at the time of bending, and the wire is disconnected due to a small number of times of bending at the FPC portion as compared to the one made of a plate b1 on which no stress acts. There was a risk.

  The present invention has been made in view of the above points, and the object of the present invention is to suppress the action of a significant restoring force due to compressive stress and tensile stress in the FPC portion composed of a plurality of plates, and to incorporate the work. It is an object of the present invention to provide a flex-rigid multilayer wiring board that can improve the durability, and can effectively prevent disconnection due to bending by improving durability during bending.

  In order to achieve the above object, the present invention presupposes a flex-rigid multi-layer wiring board in which multi-layer circuit board parts each having a plurality of conductor layers each formed with a circuit are electrically connected by a flexible FPC part. The FPC portion is composed of a plurality of plates that electrically and independently connect the conductor layers of the multilayer substrate portion individually. Then, the lengths of the lead-out directions of the respective plates led out from the respective conductor layers are different so that when the multilayer substrate portions are bent at the FPC portion, the outer plate is longer than the inner plate. It is

  Due to this specific matter, the length in the direction of leading out of the plurality of plates derived from each conductor layer is different so that the plate located outside when bent is longer than the plate located inside, When the multilayer substrate portions are bent at the FPC portion and incorporated into the device, the outer plate is bent with a bending radius larger than the bending radius of the inner plate, and a plurality of plates overlap in the FPC portion (bending portion). They do not interfere with each other. As a result, it is reliably avoided that a compressive stress is generated on the inner plate with the FPC portion bent and a slack is generated or a tensile stress is generated on the outer plate and a strong tension is applied. It is possible to improve the assembling workability by preventing a significant restoring force from returning to the original state from acting on each plate, and not impairing the workability during assembling into the device. Moreover, tensile stress or compressive stress does not act on the outer plate and inner plate bent at the time of incorporation, and even if it is repeatedly bent and used, no excessive stress is applied to the circuit pattern, It is also possible to improve durability during bending, and it is possible to effectively avoid disconnection due to bending at the FPC portion.

  In order to achieve the above object, as another solution, a flex rigid formed by electrically connecting multi-layer substrate portions each having a plurality of conductor layers each having a circuit formed by an FPC portion having flexibility. Similarly, assuming a multilayer wiring board, the FPC portion is composed of a plurality of plates that electrically and independently connect the conductor layers of the multilayer substrate portion individually. The plurality of plates derived from the respective conductor layers of the multilayer substrate portion are made different from each other in a direction orthogonal to the extraction direction so that the plates do not overlap each other when viewed from the layer thickness direction of the multilayer substrate portion. Respectively.

  Due to this specific matter, the plurality of plates derived from the respective conductor layers of the multilayer substrate portion are made different from each other in the direction orthogonal to the derived direction so that the plates do not overlap each other when viewed from the layer thickness direction of the multilayer substrate portion. Therefore, when the multilayer substrate portions are bent at the FPC portion and incorporated in the device, the respective substrates are bent at positions where they do not overlap each other when viewed from the layer thickness direction of the multilayer substrate portion. Even if each plate is bent in the portion (bent portion), the plates do not overlap each other and interfere with each other. As a result, it is reliably avoided that a compressive stress is generated on the inner plate with the FPC portion bent and a slack is generated or a tensile stress is generated on the outer plate and a strong tension is applied. As a result, it is possible to prevent a significant restoring force from returning to the original state from acting on each plate, and not to impair the workability at the time of assembling into a device, thereby improving the workability of assembling. In addition, tensile stress or compressive stress does not act on each plate bent at the time of assembly, and even if it is repeatedly bent and used, excessive stress is not applied to the circuit pattern, and durability at the time of bending is improved. It is also possible to improve, and it is possible to effectively avoid disconnection due to bending at the FPC portion.

  Here, the lead-out positions of the plurality of boards derived from the respective conductor layers are determined based on the lead-out lengths of the boards located on the inner side when the multi-layer board parts are bent at the FPC part. If the difference is stepwise in the lead-out direction when viewed from the side perpendicular to the layer thickness direction of the multilayer substrate part, the lead-out length of the outer plate is larger than the inner plate. When the multi-layer substrate portions are bent at the FPC portion and incorporated in the apparatus, a difference in the bending radius of the respective plates occurs, and the overlapping of the respective plates is prevented from interfering with each other. As a result, it is more reliably avoided that the FPC portion is bent and the inner plate is compressed to generate a slack, or the outer plate is pulled and a tensile stress is applied to exert a strong tension. It is possible to improve the workability of installation by preventing the significant restoring force that tries to restore the part from acting on each plate, and without impairing the workability when installing in equipment. Become. In addition, it avoids the application of tensile stress or compressive stress to each plate bent at the time of assembly, and even if it is repeatedly bent, it does not apply excessive stress to the circuit pattern, and at the time of bending Further, the durability can be further improved, and disconnection due to bending at the FPC portion can be effectively avoided.

  Furthermore, when the board located outside when the multi-layer board parts are bent at the FPC part is extended so as to have a larger bending radius than the board located inside, the board located outside is The lead-out length is extended longer than the plate located on the inner side, the radius of curvature of the plate located on the outer side is surely larger than the plate located on the inner side, and the multilayer substrate portions are bent at the FPC portion. When incorporating into a device, it is ensured that the plates overlap each other and interfere with each other due to the difference in bending radius of the plates. As a result, it is more reliably avoided that the FPC portion is bent and the inner plate is compressed to generate a slack, or the outer plate is pulled and a tensile stress is applied to exert a strong tension. It is possible to further suppress the workability when assembling into the equipment, and to further improve the workability of the assembly, by reliably suppressing the action of a significant restoring force to return the part to each plate. It becomes. In addition, it avoids the application of tensile stress or compressive stress to each plate bent at the time of assembly, and even if it is repeatedly bent, it does not apply excessive stress to the circuit pattern, and at the time of bending The durability can be further improved, and disconnection due to bending at the FPC portion can be avoided more effectively.

  In short, the length of the plurality of plates led out from each conductor layer in the lead-out direction is different so that the outer plate is longer than the inner plate when bent. When the board parts are bent at the FPC part and incorporated into the device, the interference between the boards at the FPC part is prevented by the difference in the bending radius between the inner board and the outer board, and the board is loosened or pulled due to compressive stress. It eliminates the generation of strong tension due to stress, suppresses the application of significant restoring force to return the bent part to each plate, and improves the workability of assembling into equipment. It is possible to prevent the action of excessive stress on the circuit pattern when bent, to improve durability during bending, and to effectively avoid disconnection due to bending at the FPC portion.

  Hereinafter, the best mode for carrying out the present invention will be described with reference to the drawings.

  FIG. 1 to FIG. 6 are explanatory views sequentially showing the manufacturing process of the flex-rigid multilayer wiring board according to the first embodiment of the present invention. FIG. 1 is a side view of the first to third FPC boards 1a to 1c before processing. Each of the FPC boards 1a to 1c is composed of a base material 11 made of polyimide, glass epoxy, or the like, and copper foils 12 and 12 stretched on both sides of the base material 11.

  FIG. 2 shows the first to third FPC boards 1a to 1c after the circuit patterns are formed, showing a state in which the circuit patterns 12a,... Are formed on the copper foils 12 and 12 on both surfaces of the base material 11 by using a known technique such as etching. FIG.

  FIG. 3 shows an insulating state in which insulating protective films 13, 13 such as coverlays are formed on the surfaces of the circuit patterns 12a,... On both sides of the first to third FPC boards 1a to 1c after the circuit pattern is formed by a known method. It is a side view of the 1st thru | or 3rd FPC board | substrates 1a-1c after protective film formation.

  FIG. 4 shows a side view of the flex-rigid multilayer wiring board A before the first to third FPC boards 1a, 1b, and 1c are laminated and integrated after the insulating protective film is formed. The flex-rigid multilayer wiring board A includes first to third conductor layers 2a, 3a, 2b in which circuit patterns 12a are formed at both ends (left and right ends in FIG. 4) of the first to third FPC boards 1a, 1b, 1c. , 3b, 2c, 3c are respectively derived from the multilayer substrate portions 2, 3 and the first to third conductor layers 2a, 3a, 2b, 3b, 2c, 3c of the multilayer substrate portions 2, 3, An FPC board portion 4 comprising first to third FPC boards 4a, 4b, 4c as plates for electrically connecting the first to third conductor layers 2a, 3a, 2b, 3b, 2c, 3c individually and independently; Is configured after the multilayer press formation. In this case, the first to third FPC boards 4a, 4b, 4c of the FPC board portion 4 are located at the center of the first to third FPC boards 1a, 1b, 1c, and the first to third conductor layers are formed after the multilayer press is formed. They are derived from 2a, 3a, 2b, 3b, 2c and 3c, respectively.

  And between the first to third conductor layers 2a, 2b and 2c in one multilayer substrate portion 2 (left multilayer substrate portion in FIG. 4) and the other multilayer substrate portion 3 (right multilayer substrate portion in FIG. 4). A sheet-like prepreg 14 made of an adhesive material is interposed between the first to third conductor layers 3a, 3b, and 3c. Further, on the upper surfaces (side surfaces of the anti-second conductor layers 2b and 3b) of the uppermost first conductor layers 2a and 3a in the multilayer substrate portions 2 and 3, a known technique such as etching is used only on the lower surface serving as the inner layer side surface. Base materials 15 made of polyimide, glass epoxy, or the like, on which circuit patterns 15 a are formed, are installed via prepregs 14. On the other hand, the lower surfaces of the lowermost third conductor layers 2c and 3c (the side surfaces opposite to the second conductor layers b and 3b) in the multilayer substrate portions 2 and 3 are formed using a known technique such as etching only on the upper surface serving as the inner layer side surface. Base materials 16 made of polyimide, glass epoxy, or the like, on which the circuit pattern 16a is formed, are installed via the prepregs 14, respectively. In this case, the copper foil 12 is stretched on the upper surface, which is the outer layer side surface of the uppermost base material 15, and the lower surface, which is the outer layer side surface of the lowermost base material 16.

  Further, a first spacer 51 is provided on the upper surface side of the FPC portion 4 on the first FPC plate 4a (on the side opposite to the second FPC plate 4b). The flat surface 51a is formed on the side surface of the anti-second FPC plate 4b that is the upper surface side of the first spacer 51, while the undulating surface that undulates in a steep pattern on the side surface of the first FPC plate 4a that is the lower surface side. 51b is formed. Further, a second spacer 52 is provided between the first FPC plate 4 a and the second FPC plate 4 b in the FPC portion 4. On the side surface of the second FPC plate 4b that is the upper surface side of the second spacer 52, there is a undulating surface 52a that undulates in a waveform in substantially the same pattern as the undulating surface of the lower surface of the first spacer 51 (side surface of the first FPC plate 4a). A corresponding undulation surface 52a is formed on the undulation surface of the lower surface of one spacer 51 with the first FPC plate 4a interposed therebetween. On the other hand, on the side surface of the second FPC plate 4b that is the lower surface side of the second spacer 52, a undulating surface 52b that undulates in a corrugated pattern is formed. Further, a third spacer 53 is provided between the second FPC plate 4 b and the third FPC plate 4 c in the FPC portion 4. On the side surface of the second FPC plate 4b that is the upper surface side of the third spacer 53, there is a undulating surface 53a that undulates in a waveform in substantially the same pattern as the undulating surface of the lower surface of the second spacer 52 (side surface of the second FPC plate 4b). A corresponding undulating surface 53a is formed on the undulating surface 52b of the lower surface of the spacer 52 with the second FPC plate 4b interposed therebetween. On the other hand, a flat surface 53 b is formed on the side surface of the third FPC plate 4 c that is the lower surface side of the third spacer 52.

  Then, as described above, the three first to third FPC boards 1a, 1b, and 1c are stacked, and between the first to third conductor layers 2a, 2b, and 2c of one multilayer board portion 2 and the other multilayer. A prepreg 14 is interposed between the first to third conductor layers 3a, 3b, 3c of the substrate portion 3, and the upper and lower layers of the uppermost first conductor layers 2a, 3a in the multilayer substrate portions 2, 3 are disposed. The base materials 15 and 16 are respectively installed on the lower surfaces of the third conductor layers 2c and 3c via the prepreg 14, and the upper surface side of the first FPC plate 4a in the FPC portion 4, between the first FPC plate 4a and the second FPC plate 4b, In addition, the first to third spacers 51 to 53 are installed between the second FPC plate 4b and the third FPC plate 4c, respectively. Suyo flex-rigid multilayer wiring board A is made thus obtained. In addition, by removing the first to third spacers 51 to 53 after pressing, the first and second FPC plates 4a and 4b in the FPC portion 4 are formed into the undulating surfaces 51b, 52a, 52b of the first to third spacers 51 to 53, respectively. The lengths of the first to third FPC plates 4a to 4c in the FPC portion 4 extended along the line 53a and led out from the multilayer substrate portions 2 and 3 are made different from each other.

  Further, as shown in FIG. 6, in the multilayer substrate portions 2 and 3, the copper foil 12 on the upper surface of the base material 15 located in the uppermost layer and the copper foil 12 on the lower surface of the base material 16 located in the lowermost layer are known such as etching. The outer layer circuit patterns 15b and 16b are formed using a technique. One multilayer substrate portion 2 is provided with a through-hole hole 61 penetrating the first to third conductor layers 2a to 2c and the uppermost and lowermost base materials 15 and 16 in the layer thickness direction. The hole hole 61 is processed by the copper plating 62 so that the circuit pattern 12a of the first to third conductor layers 2a to 2c of the multilayer substrate portion 2 and the outer layer circuit of the base materials 15 and 16 of the uppermost layer and the lowermost layer. The patterns 15b and 16b are connected so as to be electrically conductive. Laser via holes 63 and 64 penetrating only the base materials 15 and 16 in the layer thickness direction are provided in the uppermost and lowermost base materials 15 and 16 of the other multilayer substrate portion 3, respectively. , 64 are respectively processed by copper plating 65 so that the circuit pattern 15a of the uppermost base material 15 of the other multilayer substrate portion 3 and the outer circuit pattern 15b are connected so as to be electrically conductive, and the lowermost layer. The circuit pattern 16a of the base material 16 and the outer layer circuit pattern 16b are connected so as to be electrically conductive. The flex-rigid multilayer wiring board A thus formed is a finished product through a solder resist, pattern surface treatment, outer shape processing, and an inspection process by a known method.

  Then, as shown in FIG. 7, when the multilayer substrate portions 2 and 3 are bent at the FPC portion 4, the second FPC plate 4b located outside is pulled longer than the third FPC plate 4c located inside. On the other hand, the first FPC board 4a positioned outside the second FPC board 4b is extended longer than the second FPC board 4b positioned inside the second FPC board 4b. When the FPC portion 4 is bent, the outermost first FPC plate 4a has the largest bending radius, the second FPC plate 4b has the largest bending radius, and the innermost third FPC plate 4c has the largest bending radius. It is getting smaller.

  Therefore, in the above embodiment, the length of the first to third FPC plates 4a to 4c derived from the first to third conductor layers 2a, 3a, 2b, 3b, 2c, and 3c of the multilayer substrate portions 2 and 3 in the direction of derivation, respectively. The second FPC board 4b located outside when the multilayer board parts 2 and 3 are bent at the FPC part 4 is elongated longer than the third FPC board 4c located inside. Since the first FPC board 4a located outside the 2FPC board 4b is different from the second FPC board 4b extended longer than the inside, the first and second FPC boards 4a, 4b located outside are located inside. The lead-out length is elongated in order from the third FPC plate 4c, and the bending radius of the outer second FPC plate 4b is surely larger than the curvature radius of the inner third FPC plate 4c. The bending radius of the 1FPC board 4a is surely larger than the curvature radius of the inner second FPC board 4b, and the inner third FPC board 4c is bent when the multilayer board portions 2 and 3 are bent at the FPC portion 4 and incorporated in the device. The outer second FPC plate 4b is bent with a bending radius larger than the bending radius of the first FPC plate 4b, and the first FPC plate 4a outside the second FPC plate 4b is bent with a bending radius larger than the bending radius of the inner second FPC plate 4b. In the FPC portion 4 (bent portion), the three first to third FPC plates 4a to 4c do not interfere with each other. As a result, in the state where the FPC portion 4 is bent, a compressive stress is generated in the inner second and third FPC plates 4b and 4c to cause looseness, and a tensile stress is generated in the outer first and second FPC plates 4a and 4b. Work to be surely avoided by applying a strong tension to the FPC plates 4a to 4c by suppressing a significant restoring force to return the bent portion to its original state. Therefore, it is possible to improve the installation workability. In addition, the outer first and second FPC plates 4a and 4b bent at the time of incorporation and the inner second and third FPC plates 4b and 4c are not subjected to tensile stress or compressive stress, and are repeatedly bent and used. However, excessive stress is not applied to the circuit pattern 12a, durability during bending can be improved, and disconnection of the first to third FPC boards 4a to 4c due to bending at the FPC portion 4 is also effective. Can be avoided.

  Next, a second embodiment of the present invention will be described with reference to FIGS.

  In the second embodiment, each FPC plate derived from each conductor layer of the multilayer substrate portion is changed. The other configurations except for the FPC board are the same as those in the first embodiment, and the same portions are denoted by the same reference numerals, and detailed description thereof is omitted.

  That is, in this embodiment, as shown in FIGS. 8 and 9, the first to third FPCs derived from the first to third conductor layers 2a, 3a, 2b, 3b, 2c, 3c of the multilayer substrate portions 2 and 3 are used. The plates 4d, 4e, and 4f are set to the same derived length. The lead position of the first FPC board 4d led out from the first conductor layers 2a and 3a of the multilayer substrate portions 2 and 3 is in a direction (vertical direction in FIG. 8) perpendicular to the lead direction of the multilayer substrate portions 2 and 3. It is positioned at one side end (upper end in FIG. 8). In addition, the lead-out position of the second FPC board 4e led out from the second conductor layers 2b and 3b of the multilayer board portions 2 and 3 is positioned at the center position in the direction orthogonal to the lead-out direction of the multilayer board parts 2 and 3. . Furthermore, the lead-out position of the third FPC board 4f led out from the third conductor layers 2c and 3c of the multilayer substrate portions 2 and 3 is in a direction (vertical direction in FIG. 8) perpendicular to the lead-out direction of the multilayer substrate portions 2 and 3. It is positioned at the other end (lower end in FIG. 8). In this case, the first to third FPC boards 4d to 4f derived from the first to third conductor layers 2a, 3a, 2b, 3b, 2c, and 3c of the multilayer substrate portions 2 and 3, respectively, A gap S is provided between the adjacent FPC plates 4d to 4f so that the FPC plates 4d to 4f do not overlap each other when viewed from the layer thickness direction (the front and back direction in FIG. 8). , 3 are derived from positions different from each other in a direction orthogonal to the direction of derivation.

  Therefore, in the above embodiment, the first to third FPC plates 4d to 4f derived from the first to third conductor layers 2a, 3a, 2b, 3b, 2c, and 3c of the multilayer substrate portions 2 and 3, respectively, Positions that are different from each other in a direction orthogonal to the lead-out direction of the multilayer substrate portions 2 and 3 with a gap S so that the FPC plates 4d to 4f do not overlap each other when viewed in the thickness direction of the layers 2 and 3. Since they are derived from one side end (upper end in FIG. 8), the center position, and the other end (lower end in FIG. 8), respectively, as shown in FIG. When the FPC portions 4 are bent at the FPC portion 4 and incorporated in the device, the FPC plates 4d to 4f are bent at positions where they do not overlap each other when viewed from the layer thickness direction of the multilayer substrate portions 2 and 3, and the FPC portion 4 (bending portion) ) Even FPC board 4D～4f is not bent, respectively, do not interfere with each other overlap each FPC board 4D～4f. As a result, in the state where the first to third FPC portions 4d to 4f are bent, the inner second and third FPC plates 4e and 4f generate a compressive stress to cause slack, or the outer plate first and second FPC plates 4d. , 4e is surely prevented from applying a strong tension due to a tensile stress, and a significant restoring force to return the bent portion to the original is suppressed from acting on each of the FPC plates 4d to 4f. The workability at the time of assembling into the camera is not impaired, and the workability at assembling can be improved.

  Moreover, tensile stress or compressive stress does not act on each of the FPC plates 4d to 4f bent at the time of incorporation, and even if they are repeatedly bent and used, excessive stress is not applied to the circuit pattern 12a. The durability at the time can also be improved, and disconnection of each of the FPC plates 4d to 4f due to bending at the FPC portion 4 can be effectively avoided.

  Next, a third embodiment of the present invention will be described with reference to FIGS.

  In the third embodiment, each FPC plate derived from each conductor layer of the multilayer substrate portion is changed. The other configurations except for the FPC board are the same as those in the first embodiment, and the same portions are denoted by the same reference numerals, and detailed description thereof is omitted.

  That is, in this embodiment, as shown in FIG. 11, the first to third FPC plates 4g derived from the first to third conductor layers 2a, 3a, 2b, 3b, 2c, 3c of the multilayer substrate portions 2 and 3, respectively. , 4h, 4i is derived from the third FPC board 4i in which the lead-out length of the second FPC board 4h located outside when the multilayer board parts 2, 3 are bent in the FPC part 4 is located further inside. The multi-layer substrate so that the lead length of the first FPC plate 4g located outside the second FPC plate 4h is longer than the lead length of the second FPC plate 4h located inside the second FPC plate 4h. When viewed from the side perpendicular to the layer thickness direction of the portions 2 and 3 (the front and back direction in FIG. 11), the third conductor layers 2c and 3c of the multi-layer substrate portions 2 and 3 are the second conductor. More conductive than layers 2b and 3c The second conductor layers 2b and 3b are recessed in the direction opposite to the first conductor layers 2a and 3a (outward in the left and right direction in FIG. 11) at a position recessed in the direction (outward in the left and right direction in FIG. 11). They are different in steps so that they are located.

  In this case, the first spacer 51 is provided on the upper surface side (on the side opposite to the second FPC plate 4h) of the first FPC plate 4g of the FPC portion 4, and the second spacer 52 is provided between the first FPC plate 4g and the second FPC plate 4h of the FPC portion 4. The third spacer 53 is installed between the second FPC plate 4h and the third FPC plate 4i of the FPC portion 4, and the first to third spacers 51 to 53 are removed after pressing by the press machine, thereby the FPC portion 4 The first and second FPC plates 4g and 4h are extended along the undulating surfaces 51b, 52a, 52b and 53a of the first to third spacers 51 to 53, and the first to third FPC plates 4g of the FPC portion 4 are extended. The lengths of ˜4i in the derivation direction are made different from each other.

  Therefore, in the above embodiment, combined with the effect of extending the first and second FPC plates 4g and 4h by the third spacers 51 to 53, as shown in FIG. The first FPC plate positioned outside the second FPC plate 4h located outside is longer than the leading length of the third FPC plate 4i positioned inside the second FPC plate 4h. The leading length of 4g becomes longer than the leading length of the second FPC board 4h on the inner side, and the first to third FPC boards are bent when the multilayer board portions 2 and 3 are bent at the FPC portion 4 and incorporated in the device. A difference occurs in the bending radii of 4g to 4i, and the FPC plates 4g to 4i are prevented from overlapping each other and interfering with each other. As a result, in the state where the FPC portion 4 is bent, a compressive stress is generated in the inner second and third FPC plates 4h and 4i to cause looseness, and a tensile stress is generated in the outer FPC plates 4g and 4h to cause a strong tension. It is more reliably avoided that it acts, and it is possible to reliably prevent the significant restoring force that tries to return the bent part from acting on each FPC plate 4g to 4i, thereby improving the workability when assembling the device. It is possible to improve the assembly workability without being damaged.

  Moreover, excessive stress is applied to the circuit pattern 12a even if the FPC plates 4g to 4i bent at the time of incorporation are surely avoided from being subjected to tensile stress or compressive stress and repeatedly bent. In addition, the durability at the time of bending can be further improved, and disconnection of the FPC plates 4g to 4i due to bending at the FPC portion 4 can be effectively avoided.

  In addition, this invention is not limited to said each Example, Other various modifications are included. For example, in each of the above-described embodiments, the flex-rigid multilayer wiring board A in which three first to third FPC boards 1a, 1b, and 1c are stacked has been described. However, two or four or more FPC boards are stacked. Of course, it can also be applied to flex-rigid multilayer wiring boards.

  Moreover, in the said Example 1 and Example 2, although the length of the 1st and 2nd FPC board 4a, 4b, 4g, 4h was extended by the spacers 51-53, the extending amount of the 1st and 2nd FPC board is only in a spacer. When there is a limit, the first and second FPC plates before lamination may be temporarily fixed to the prepreg, the positions thereof may be shifted, and then the lamination may be performed thereafter.

It is a side view of the 1st thru | or 3rd FPC board | substrate which shows the state which spread | stretched copper foil on both surfaces of the base material before the process of the flex-rigid multilayer wiring board concerning Example 1 of this invention. It is a side view of the 1st thru | or 3rd FPC board after circuit pattern formation which shows the state in which the circuit pattern was similarly formed in the copper foil of both sides of a base material. It is the side view of the 1st thru | or 3rd FPC board after the formation of the insulation protective film which similarly shows the state in which the insulation protective film was formed. FIG. 6 is a side view of the flex-rigid multilayer wiring board before the first to third FPC boards having been similarly formed with the insulating protective film are stacked and integrated. It is the side view of the flex-rigid multilayer wiring board after the same press. It is the side view of the flex-rigid multilayer wiring board completed similarly. It is a side view of a flex-rigid multilayer wiring board showing a state where the multilayer substrate portions are similarly bent at the FPC portion. It is the top view which looked at the flex-rigid multilayer wiring board concerning Example 2 of this invention from the layer thickness direction. It is a side view of a flex-rigid multilayer wiring board. It is a side view of a flex-rigid multilayer wiring board showing a state where the multilayer substrate portions are similarly bent at the FPC portion. It is a side view of the flex-rigid multilayer wiring board concerning Example 3 of the present invention. It is a side view of a flex-rigid multilayer wiring board showing a state where the multilayer substrate portions are similarly bent at the FPC portion. It is a side view of the flex-rigid multilayer wiring board in which the FPC part concerning a prior art example was comprised by one board. It is a side view of the flex-rigid multilayer wiring board by which the FPC part concerning a prior art example was comprised by the board of 2 sheets. It is a side view of the flex-rigid multilayer wiring board in which the FPC part concerning a prior art example was comprised by the board of 3 sheets. It is a side view of the flex-rigid multilayer wiring board which shows the state bent in the FPC part comprised by the board of 2 sheets concerning a prior art example.

Explanation of symbols

2, 3 Multilayer substrate portions 2a, 3a First conductor layers 2b, 3b Second conductor layers 2c, 3c Third conductor layer 4 FPC portions 4a, 4d, 4g
1st FPC board (board)
4b, 4e, 4h
Second FPC board (board)
4c, 4f, 4i
3rd FPC board (board)
A Flex-rigid multilayer wiring board

Claims (4)

A flex-rigid multilayer wiring board formed by electrically connecting multilayer substrate portions each having a plurality of conductor layers formed with circuits by FPC portions having flexibility,
The FPC portion is composed of a plurality of plates that electrically and independently connect the conductor layers of the multilayer substrate portion individually,
The lengths of the lead-out directions of the respective plates derived from the respective conductor layers are made different so that when the multilayer substrate portions are bent at the FPC portion, the outer plate is longer than the inner plate. A flex-rigid multilayer wiring board. A flex-rigid multilayer wiring board formed by electrically connecting multilayer substrate portions each having a plurality of conductor layers formed with circuits by FPC portions having flexibility,
The FPC portion is composed of a plurality of plates that electrically and independently connect the conductor layers of the multilayer substrate portion individually,
The plurality of plates derived from the respective conductor layers are respectively derived from positions that are different from each other in the direction orthogonal to the derived direction so that the respective plates do not overlap each other when viewed from the layer thickness direction of the multilayer substrate portion. A flex-rigid multilayer wiring board. In the flex-rigid multilayer wiring board according to claim 1 or 2,
The lead-out positions of the plurality of plates led out from the respective conductor layers are longer than the lead-out lengths of the plates located on the inner side when the multilayer substrate portions are bent at the FPC portions. As described above, the flex-rigid multilayer wiring board is characterized by being stepped in the lead-out direction when viewed from the side perpendicular to the layer thickness direction of the multilayer substrate portion. In the flex-rigid multilayer wiring board according to claim 1 or 3,
A flex-rigid multilayer wiring board characterized in that a board located outside when the multilayer board parts are bent at the FPC part is elongated so that a bending radius is larger than a board located inside.

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