JP4921264B2 - Flexible wiring board - Google Patents

Description

  The present invention relates to a flexible wiring board that connects a rigid board and a module, and more particularly to a flexible wiring board that prevents disconnection due to handling during mounting.

  A flexible wiring board is employed for an electrical interface of a module that supports a modulation operation of 10 Gbps such as XMD-MSA (Miniature Device Multi Source Agreement). When this module is mounted on a transceiver, the pad of the rigid board of the transceiver and the pad of the flexible wiring board are soldered.

  4A and 4B are schematic views showing an example of a conventional flexible wiring board, in which FIG. 4A shows one surface and FIG. 4B shows the other surface. The flexible wiring board 23 has pads and wiring formed on the surface of the flexible sheet 11. On one surface of the flexible wiring board 23 shown in FIG. 4 (a), rigid board connection side pads 12a, 12b, 12c, 12d, 12e, 12f connected to the rigid board at one end of the flexible sheet 11, 12g and 12h are arranged, and module connection side pads 13a, 13b, 13c, 13d, 13e, 13g and 13h connected to the module are arranged at the other end of the flexible sheet 11.

  Wiring drawn from the rigid board connection side pads 12a, 12b, 12c, 12d, 12e, 12f, 12g, and 12h is electrically connected to the module connection side pads 13a, 13b, 13c, 13d, 13e, 13g, and 13h. The Also, functional wiring such as high-frequency signal input wiring and LD bias current supply wiring is patterned on the surface of the flexible sheet 11. On the other surface (back surface) of the flexible wiring board 23 shown in FIG. 4B, the GND pattern 17 for impedance matching of the high-frequency signal wiring is wired on the surface of the flexible sheet 11, The back pads 27d and 27f are connected to the module connection side pad 13d. The rigid substrate connection side pads 12a and 12h are connected to the back pads 27a and 27h on the rigid substrate connection side via the rigid substrate connection side vias 14a and 14h, respectively (see, for example, Patent Document 1).

FIG. 5 is a schematic diagram showing an example of mounting the module and the rigid board. The rigid board connection side pads (reference numerals 12a, 12b, 12c, 12d, 12e, 12f, 12g, and 12h in FIG. 4) formed on one end of the flexible wiring board 23 are electrically connected to the rigid board 21 by solders 24 and 25. Connected. The other module connection side pads (reference numerals 13a, 13b, 13c, 13d, 13e, 13g, and 13h in FIG. 4) are electrically connected to the module 22 by soldering with the lead pins 26. One surface of the flexible sheet 11, that is, the surface on which functional wiring is patterned is a contact surface with the rigid substrate 21.
JP 2007-12934 A

  When the flexible wiring board 23 is mounted on the rigid board 21 or the module 22, the module connection side pads (the reference numerals 12a, 12b, 12c, 12d, 12e, 12f, 12g, 12h in FIG. 4) of the rigid board connection side pads ( The peripheral portion A ′ on the side of reference numerals 13 a, 13 b, 13 c, 13 d, 13 e, 13 g, 13 h in FIG. 4 is bent in the A direction parallel to the normal direction of the substrate surface of the rigid substrate 21, and is in contact with the rigid substrate 21. Tensile stress concentrates at a position A ′ on one surface of the flexible wiring board 23 that is present. The thickness of the wiring on the flexible sheet 11 is as very thin as 30 μm to 50 μm, and if the solder is fixed, it is easily disconnected due to tensile stress. For this reason, there has been a problem that the wiring patterned at the position A ′ on one surface of the flexible sheet 11 is disconnected.

  Although it is possible to pattern functional wiring on the back surface of the flexible sheet 11, a force in the B direction parallel to the substrate surface of the rigid substrate 21 is often applied, and in this case, stress is concentrated at the position B ′. And the same problem occurs. In addition, when functional wiring is patterned on the back surface of the flexible sheet 11, there is no gap between the module 22 and the flexible wiring board 23, and thus there is a problem that visual inspection of the flexible wiring board 23 cannot be performed after soldering. .

  Therefore, an object of the present invention is to prevent disconnection of wiring patterned on a flexible sheet in a flexible wiring board.

  The present invention relates to a double-sided flexible wiring board that connects a module and a rigid board, and the wiring formed on the flexible sheet drawn out from the rigid board side is patterned so as to avoid stress caused by bending during mounting. Has been.

Specifically, the flexible wiring board according to the present invention, the signal input lines on one surface is patterned, GND pattern for impedance matching on the other surface is the one of the flexible sheet having flexibility that is patterned are arranged on the surface, and the rigid substrate connection side pad to be connected to the rigid board transceiver, the disposed on the one surface of the flexible sheet, and the module connection side pads connected to lead pins of the module for modulating operation, the disposed on both sides in a by and between the module connection side pad and the rigid substrate connection side pads and ends of the flexible sheet of flexible sheet, the said rigid substrate connecting side pads from the one surface of the flexible sheet a rigid substrate connection side via for conducting the other surface, the Lexical Bull a double-sided of the sheet is between the module connection side pad and the rigid substrate connection side pads and said arranged at both ends of the flexible sheet, the rigid substrate connection side vias and electrically in the other surface of the flexible sheet to be connected, characterized in that it comprises a module connection side via which the are modules connected side pad electrically connected to said at one surface of the flexible sheet.

  In the flexible wiring board according to the present invention, since the rigid board connection side via conducts from one surface of the flexible sheet to the other surface, the wiring connected to the peripheral part on the module connection side pad side of the rigid board connection side pad The other surface of the flexible sheet can be patterned. Even if one side of the flexible sheet is curved outward, the other side of the flexible sheet is unlikely to generate stress that causes disconnection of the wiring, such as tensile stress. It is possible to prevent disconnection of the connected wiring.

The flexible wiring substrate according to the present invention, the signal input lines on one surface is patterned, disposed on the one surface of the flexible sheet having flexibility GND pattern for impedance matching is patterned on the other surface A rigid board connection side pad connected to the rigid board of the transceiver, a module connection side pad arranged on the one surface of the flexible sheet and connected to a lead pin of the module performing a modulation operation, and the flexible sheet wherein the rigid substrate connection side pad is between the module connection side pads and said arranged at both ends of the flexible sheet a double-sided, conducted to the other surface of the rigid substrate connecting side pads from the one of the flexible sheet a rigid substrate connection side via which the Furekishibu It is disposed a double-sided sheets to both ends of the the rigid substrate connection side pad is between the module connection side pad and the flexible sheet, electrical and the rigid substrate connection side vias in the other surface of the flexible sheet is connected to the the module connection side via said connected the module connection side pad and electrically at one side of the flexible sheet, and the rigid substrate connection side pad wherein a second surface of the flexible sheet The module connection side between the module connection side pads and disposed at both ends of the flexible sheet, electrically connecting the rigid board connection side via and the module connection side via, and the module connection side with respect to the rigid board connection side via The rigid substrate connection side via and the direction different from the direction of the via side Characterized in that it comprises a and a back surface bypass wiring that is continued.

  In the flexible wiring board according to the present invention, since the rigid board connection side via conducts from one surface of the flexible sheet to the other surface, the wiring connected to the peripheral part on the module connection side pad side of the rigid board connection side pad The other surface of the flexible sheet can be patterned. Even if one side of the flexible sheet is curved outward, the other side of the flexible sheet is unlikely to generate stress that causes disconnection of the wiring, such as tensile stress. It is possible to prevent disconnection of the connected wiring.

  Furthermore, in the flexible wiring board according to the present invention, the back surface bypass wiring is connected to the rigid board connection side pad from a direction different from the direction of the module connection side pad side with respect to the rigid board connection side pad. The periphery of the pad on the module connection side pad side can be bypassed. Since the greatest stress is generated in the peripheral part of the rigid board connection side pad on the module connection side pad side, the back surface detour wiring bypasses the peripheral part of the rigid board connection side pad on the module connection side pad side. When the sheet is curved so that one surface of the sheet is on the outside, disconnection of the wiring patterned on the flexible sheet can be prevented even with wiring on one side.

  According to the present invention, disconnection of wiring patterned on the flexible sheet can be prevented.

Embodiments of the present invention will be described with reference to the accompanying drawings. The embodiment described below is an example of the configuration of the present invention, and the present invention is not limited to the following embodiment.
(Embodiment 1)
1A and 1B are schematic views of a flexible wiring board according to Embodiment 1, in which FIG. 1A shows one surface and FIG. 1B shows the other surface. Functional wiring is wired on one surface of the flexible sheet 11 shown in FIG. In the present embodiment, one surface of the flexible sheet 11 will be described as the front surface, and the other surface of the flexible sheet 11 will be described as the back surface.

  The flexible wiring board according to the present embodiment includes rigid board connection side pads 12a, 12b, 12c, 12d, 12e, 12f, 12g, and 12h, module connection side pads 13a, 13b, 13c, 13d, 13e, 13g, and 13h. , Rigid substrate connection side vias 14a and 14h, and module connection side vias 15a and 15h. In addition, the flexible wiring board may include backside pads 27a, 27b, 27c, 27d, 27e, 27f, 27g, and 27h on the rigid board connection side.

  The rigid board connection side pad 12a and the module connection side pad 13a are electrically connected. The rigid board connection side pad 12b and the module connection side pad 13b are electrically connected. The rigid board connection side pad 12c and the module connection side pad 13c are electrically connected. The rigid board connection side pad 12d and the module connection side pad 13d are electrically connected. The rigid board connection side pad 12e and the module connection side pad 13e are electrically connected. The rigid board connection side pad 12f and the module connection side pad 13d are electrically connected. The rigid board connection side pad 12g and the module connection side pad 13g are electrically connected. The rigid board connection side pad 12h and the module connection side pad 13h are electrically connected.

  The rigid board connection side via 14a and the module connection side via 15a are disposed between the rigid board connection side pad 12a and the module connection side pad 13a. The rigid board connection side pad 12a, the rigid board connection side via 14a, the module connection side via 15a, and the module connection side pad 13a are electrically connected in this order. Similarly, the rigid board connection side via 14h and the module connection side via 15h are arranged between the rigid board connection side pad 12h and the module connection side pad 13h, and the rigid board connection side pad 12h, the rigid board connection side via 14h, and the module connection. The side vias 15h and the module connection side pads 13h are electrically connected in this order. It is preferable that the rigid board connection side via and the module connection side via are provided in a wiring patterned at a location where tensile stress is concentrated when the flexible wiring board is bent. For example, as shown in FIG. 1, it is preferable to be provided in the wiring of the rigid board connection side via 14a and the rigid board connection side via 14h formed at both ends of the flexible sheet 11.

  The flexible sheet 11 is a flexible substrate. For example, a resin substrate. In the present embodiment, since wiring is patterned on both the front and back surfaces, a substrate capable of double-side patterning is preferable. An example of a substrate capable of double-side patterning is a polyimide substrate.

  The rigid board connection side pads 12a, 12b, 12c, 12d, 12e, 12f, 12g, and 12h are formed on one surface of the flexible sheet 11, and are electrically connected to the rigid board. The rigid board connection side pads 12a, 12b, 12c, 12d, 12e, 12f, 12g, and 12h are formed at one end of the flexible sheet 11, for example. The connection between the rigid board connection side pads 12a, 12b, 12c, 12d, 12e, 12f, 12g, and 12h and the rigid board is, for example, solder connection.

  In the present embodiment, the rigid board connection side pads 12a, 12b, 12c, 12d, 12e, 12f, 12g, and 12h are each formed with vias, and not only one surface of the flexible sheet 11 but also the flexible sheet 11 An example is shown in which the other surface is also conductive. The back side pads 27a, 27b, 27c, 27d, 27e, 27f, 27g, and 27h on the rigid board connection side are provided on the rigid board connection side pads 12a, 12b, 12c, 12d, 12e, 12f, 12g, and 12h, respectively. The vias are connected to the rigid substrate connection side pads 12a, 12b, 12c, 12d, 12e, 12f, 12g, and 12h.

  The rigid substrate connection side vias 14a and 14h respectively connect the rigid substrate connection side pads 12a and 12h from one surface of the flexible sheet 11 to the other surface. The rigid board connection side vias 14a and 14h make the inner walls of the through holes provided in the rigid board connection side pads 12a and 12h conductive, for example, by metal plating. The number of rigid substrate connection side vias 14a and 14h is one or more. In the present embodiment, as an example, the case where there are three rigid substrate connection side vias 14a and 14h is shown.

  In the flexible wiring board according to the present embodiment, since the rigid board connection side vias 14a and 14h are electrically connected from one surface of the flexible sheet 11 to the other surface, the rigid board connection side pads 12a and 12h and the module connection side pads 13a and The back surface wirings 19a and 19h for connecting to 13h can be patterned on the other surface of the flexible sheet 11, as shown in FIG. The other surface of the flexible sheet 11 shown in FIG. 1 (b) is patterned on one surface of the flexible sheet 11 shown in FIG. 1 (a) because a large tensile stress is not partially applied when the flexible wiring board is mounted. It is possible to prevent disconnection of the connected wiring.

  The module connection pads 13a, 13b, 13c, 13d, 13e, 13g, and 13h are provided with a module connection mechanism. The connection mechanism with the module is, for example, an insertion port into which the lead pin 26 shown in FIG. 5 is inserted. The insertion port into which the lead pin is inserted may be used as a via.

  The rigid board connection side pads 12a, 12b, 12c, 12d, 12e, 12g, and 12h are electrically connected to the module connection side pads 13a, 13b, 13c, 13d, 13e, 13g, and 13h, respectively, by wiring. . In this embodiment, in particular, the module connection side via 15a and the rigid board connection side via 14a are provided between the rigid board connection side pad 12a and the module connection side pad 13a, and the rigid board connection side pad 12a and the module connection side are provided. The pad 13a is electrically connected through the module connection side via 15a and the rigid substrate connection side via 14a. The same applies to the connection between the rigid board connection side pad 12h and the module connection side pad 13h, and they are electrically connected via the module connection side via 15h and the rigid board connection side via 14h.

  The module connection side vias 15a and 15h are electrically connected to the rigid board connection side vias 14a and 14h on the other surface of the flexible sheet 11, respectively, and the module connection side pads 13a and 13h on one surface of the flexible sheet 11. Electrically connected. The number of vias in the module connection side vias 15a and 15h is one or more. In the present embodiment, as an example, the case where there are three module connection side vias 15a and five module connection side vias 15h is shown. In addition, the surface of the flexible sheet 11 is not provided with wiring for connecting the rigid board connection side vias 14a and 14h and the module connection side vias 15a and 15h, but the rigid board connection side pads 12a and 12h. Wiring for connecting the module connection side vias 15a and 15h may be provided. By providing wiring on both the front and back surfaces of the flexible sheet 11, the risk of disconnection of the wiring can be reduced.

  In this embodiment, since the only part to be bent is A ′, the periphery of the rigid substrate connection side pads 12a and 12h is the backside wiring. However, when the other part is also bent, patterning is performed on that part. It is preferable to use a backside wiring so that a tensile stress is not applied to the wired wiring. For example, if the position where the surface of the flexible sheet 11 is bent is the periphery of the module connection side pads 13a and 13h, it is preferable that the wiring drawn from the module connection side pads 13a and 13h is wired on the back surface. . Thus, it is preferable to change suitably the location and the number of the patterning on the back surface according to the location and the number of the bent portions.

  As described above, the back surface wirings 19a and 19h drawn from at least one rigid board connection side pads 12a and 12h at one end of the flexible sheet 11, and the at least one module connection side pads 13a and 13h at the other end. The wirings 18a and 18h are patterned on opposite surfaces of the single flexible sheet 11, and the respective wirings are connected by the module connection side vias 15a and 15h. In the present embodiment, tensile stress is generated on the surface of the flexible sheet 11 located in the A ′ portion around the rigid board connection side pads 12a and 12h, and the wiring is easily disconnected. Therefore, the wiring is easily pulled out from the rigid board connection side pads 12a and 12h. Since the back surface wirings 19 a and 19 h at the location A ′ are back surface wirings, it is possible to prevent the wiring from being disconnected due to the tensile stress applied to the surface of the flexible sheet 11.

(Embodiment 2)
2A and 2B are schematic views of the flexible wiring board according to the second embodiment, where FIG. 2A shows one surface and FIG. 2B shows the other surface. The flexible wiring board shown in FIG. 2 includes bypass wirings 16a and 16h instead of the rigid board connection side via and the module connection side via described in the first embodiment. Specifically, the flexible wiring board according to the present embodiment includes rigid board connection side pads 12a, 12b, 12c, 12d, 12e, 12f, 12g, and 12h, and module connection side pads 13a, 13b, 13c, 13d, and 13e. , 13g, 13h and detour wirings 16a, 16h.

  The bypass wirings 16a and 16h electrically connect the rigid board connection side pads 12a and 12h and the module connection side pads 13a and 13h, respectively. Further, the bypass wirings 16a and 16h are connected to the rigid board connection side pads from a direction different from the direction of the module connection side pads 13a and 13h with respect to the rigid board connection side pads 12a and 12h. When the rigid board connection side pad 12a is solder-connected to the rigid board (reference numeral 21 in FIG. 5), the peripheral A ′ portion on the module connection side pad 13a side of the rigid board connection side pad 12a is bent outward, and the flexible sheet 11 The wiring patterned in the A ′ portion on the surface of the wire becomes easy to break. However, since the bypass wiring 16a bypasses the vicinity of the A ′ portion around the module connection side pad 13a of the rigid board connection side pad 12a, even if one surface of the flexible sheet 11 is curved so as to be outside. Further, it is possible to prevent disconnection of the wiring patterned at the position A ′ on one surface of the flexible sheet 11. The flexible wiring board according to the present embodiment can prevent the wiring from being disconnected only on the surface of the flexible sheet 11. Since all functional wiring can be patterned on one surface of the flexible sheet 11, visual inspection of the disconnection of the wiring can be facilitated.

  The bypass wiring 16a is connected to the rigid board connection side pad 12a from a direction different from the direction of the module connection side pad 13a side with respect to the rigid board connection side pad 12a, for example. The direction different from the direction of the module connection side pad 13a with respect to the rigid board connection side pad 12a is, for example, a direction orthogonal to a straight line connecting the rigid board connection side pad 12a and the module connection side pad 13a. Moreover, the direction opposite to the direction of the module connection side pad 13a side with respect to the rigid board | substrate connection side pad 12a may be sufficient.

(Embodiment 3)
FIG. 3 is a schematic diagram of a flexible wiring board according to Embodiment 3, wherein (a) shows one surface and (b) shows the other surface. In the flexible wiring board shown in FIG. 3, the back surface wirings connecting the rigid substrate connection side vias 14a and 14h and the module connection side vias 15a and 15h described in the first embodiment are the back surface bypass wirings 20a and 20h. Specifically, the flexible wiring board according to the present embodiment includes rigid board connection side pads 12a, 12b, 12c, 12d, 12e, 12f, 12g, and 12h, and module connection side pads 13a, 13b, 13c, 13d, and 13e. , 13g, 13h, rigid substrate connection side vias 14a, 14h, module connection side vias 15a, 15h, and back surface bypass wirings 20a, 20h.

  The back surface bypass wirings 20a and 20h electrically connect the rigid board connection side vias 14a and 14h to the module connection side vias 15a and 15h, and are on the module connection side vias 15a and 15h side with respect to the rigid board connection side vias 14a and 14h. The rigid substrate connection side vias 14a and 14h are connected from a direction different from the direction. Since the rigid substrate connection side vias 14a and 14h conduct from one surface of the flexible sheet 11 to the other surface, wiring connected to the peripheral portions of the rigid substrate connection side pads 12a and 12h on the module connection side pads 13a and 13h side Can be patterned on the other surface of the flexible sheet 11. Further, the back surface bypass wirings 20a and 20h bypass the A ′ portion where the flexible sheet 11 is bent and a tensile stress is generated. As a result, the disconnection of the wiring patterned in the A ′ portion of the flexible sheet 11 can be prevented.

  In the first embodiment, the second embodiment, and the third embodiment, in order to avoid the tensile stress on the surface of the flexible sheet 11 generated in the vicinity of the rigid board connection side pads 12a and 12h, vias are provided in the rigid board connection side pads 12a and 12h. Alternatively, bypass wiring or vias and back surface bypass wiring are provided, but the present invention is not limited thereto. When there are a plurality of bent portions of the flexible sheet 11, by providing vias, detour wires, back surface detour wires, or a combination thereof in the portions where the tensile stress is generated, disconnection of the wires due to the tensile stress generated in the bent portions Can be prevented.

  Can be used for module electrical interface

It is a schematic diagram of the flexible wiring board concerning Embodiment 1, (a) shows one side and (b) shows the other side. It is a schematic diagram of the flexible wiring board concerning Embodiment 2, (a) shows one side and (b) shows the other side. It is a schematic diagram of the flexible wiring board concerning Embodiment 3, (a) shows one side and (b) shows the other side. It is a schematic diagram which shows an example of the conventional flexible wiring board, (a) shows one surface and (b) shows the other surface. It is a schematic diagram which shows an example of mounting of a module and a rigid board | substrate.

Explanation of symbols

11 Flexible sheet 12a, 12b, 12c, 12d, 12e, 12f, 12g, 12h Rigid board connection side pad 13a, 13b, 13c, 13d, 13e, 13g, 13h Module connection side pad 14a, 14h Rigid board connection side via 15a, 15h Module connection side via 16a, 16h Detour wiring 17 GND pattern 18a, 18h Wiring 19a, 19h Back surface wiring 20a, 20h Back surface detour wiring 21 Rigid board 22 Module 23 Flexible wiring board 24, 25 Solder 26 Lead pins 27a, 27b, 27c, 27d 27e, 27f, 27g, 27h Back side pad on rigid board connection side

Claims (2)

Signal input wiring on one surface is patterned, rigid the GND pattern for impedance matching on the other side is arranged on the one surface of the flexible sheet having flexibility that is patterned is connected to the rigid board transceiver A board connection side pad;
A module connection side pad disposed on the one surface of the flexible sheet and connected to a lead pin of a module that performs a modulation operation ;
Wherein disposed between a and and both ends of said flexible sheet of a double-sided flexible sheet and the rigid substrate connection side pads the module connection side pad, the rigid substrate connecting side pads from the one surface of the flexible sheet a rigid substrate connection side via for conducting the other surface,
Wherein a side of the flexible sheet is between the module connection side pad and the rigid substrate connection side pads and arranged at both ends of said flexible sheet, said rigid substrate connection side vias in the other surface of the flexible sheet are electrically connected to a flexible wiring board and a module connection side via which the are modules connected side pad electrically connected to said at one surface of the flexible sheet. Signal input wiring on one surface is patterned, rigid the GND pattern for impedance matching on the other side is arranged on the one surface of the flexible sheet having flexibility that is patterned is connected to the rigid board transceiver A board connection side pad;
A module connection side pad disposed on the one surface of the flexible sheet and connected to a lead pin of a module that performs a modulation operation ;
Wherein is between a double-sided flexible sheet and the rigid substrate connection side pads the module connection side pads and said arranged at both ends of the flexible sheet, the other of said rigid substrate connecting side pads from the one of the flexible sheet A rigid board connection side via that is electrically connected to the surface of
Wherein a side of the flexible sheet is between the module connection side pad and the rigid substrate connection side pads and arranged at both ends of said flexible sheet, said rigid substrate connection side vias in the other surface of the flexible sheet are electrically connected to said flexible sheet wherein the module connection side pad electrically connected to the referenced module connection side via said at one surface of,
The other side of the flexible sheet, between the rigid board connection side pad and the module connection side pad and at both ends of the other side of the flexible sheet, the rigid board connection side via and the Electrically connecting a module connection side via, and a back surface bypass wiring connected to the rigid board connection side via from a direction different from the direction of the module connection side via side with respect to the rigid board connection side via;
A flexible wiring board comprising:

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