JP2007123183A - Connector for flexible board, board connection structure, optical transmitter and receiver module, and optical transmitter/receiver - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a connector for a flexible board capable of improving a transmission characteristic of a high-frequency signal in a connection part between the flexible board and another board. <P>SOLUTION: This FPC connector 1 is provided with a housing 4 having a housing opening 4b opened and closed by a housing opening/closing part 4a. In the housing 4, contacts 5 in each of which a projecting part for a transmission line is not formed from an FPC connection part 5a connected to a connection terminal of a flexible board 2 to a board connection part 5c connected to a connection terminal of a rigid board 3 are arranged at predetermined intervals. By inserting the flexible board 2 into the housing opening 4b by putting the connection terminals downward with the housing opening/closing part 4a opened and then closing the housing opening/closing part 4a, the flexible board 2 is pressed downward by the housing opening/closing part 4a, and the contact terminals of the flexible board 2 and the FPC connection parts 5a of the contacts 5 are brought into contact with each other. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a flexible substrate connector, a substrate connection structure including the flexible substrate connector, an optical transmission / reception module, and an optical transmission / reception device. Specifically, no protrusion is formed on the transmission line from the insertion board connection part connected to the connection terminal of the flexible board to the mounting board connection part connected to the connection terminal of the printed board on which the connector for the flexible board is mounted. By providing the contact, it is possible to improve the transmission characteristics of the high-frequency signal at the connection point between the flexible substrate and the other substrate.

  When electrically connecting a flexible flexible substrate and another substrate or the like, a method of connecting via a connector for connecting a flexible substrate is used. As the flexible board connector, a connector that is mounted on a printed board and includes a housing that accommodates a plurality of contacts at predetermined intervals in an opening into which the flexible board is inserted is used.

  17 and 18 are explanatory views showing a conventional flexible board connector 50 (hereinafter referred to as an FPC (Flexible Printed Circuit) connector 50) and a board connection structure including the FPC connector 50. FIG. FIG. 17 is a perspective view schematically showing the FPC connector 50, and shows a state in which a housing opening / closing portion 54a described later is opened. FIG. 18 is a cross-sectional view showing a board connection structure provided with an FPC connector 50. The FPC connector 50 is mounted on a rigid board 53, and a housing opening / closing portion 54a to be described later is closed with the flexible board 52 connected. Is shown. The rigid substrate 53 shows a part of the configuration.

  As shown in FIGS. 17 and 18, the FPC connector 50 includes a housing 54 having a housing opening 54b that is opened and closed by a housing opening and closing portion 54a. Inside the housing 54 is a metal in which a support portion 55d for supporting the housing 54, an FPC connection portion 55a connected to a connection terminal of the flexible substrate 52 inserted into the housing opening 54b, and a lead portion 55d are integrally formed. The contacts 55 configured by are accommodated in parallel at a predetermined interval. The support portion 55d and the FPC connection portion 55a are formed so as to protrude in the horizontal direction from the lead portion 55b and to be positioned substantially parallel in the vertical direction. In addition, a substrate connection portion 55 c connected to a connection terminal of the rigid substrate 53 is provided at the end of the lead portion 55 b of the contact 55.

  The support portion 55 d of each contact 55 is inserted into a support portion insertion portion 54 d provided at a lower portion of the housing opening portion 54 b of the housing 54. Further, the FPC connection portion 55 a is located in a connection portion accommodation groove 54 c provided in the housing 54. The end portion of the FPC connection portion 55a connected to the connection terminal of the flexible substrate 52 is in a state of protruding a predetermined amount from the connection portion receiving groove 54c.

  When the housing opening / closing part 54a is opened, the flexible board 52 is pressed downward by inserting the flexible board 52 into the housing opening 54b with the connection terminal facing downward, and closing the housing opening / closing part 54a. As shown, the connection terminal of the flexible substrate 52 and the FPC connection part 55a of the contact 55 are in contact with each other. The type of FPC connector that comes into contact with the connection terminal located on the lower surface of the flexible substrate 52 is called a lower contact type.

  Further, as shown in P of FIG. 18, the board connection portion 55 c of the contact 55 is connected to the connection terminal of the rigid board 53 by solder.

  Here, as the flexible substrate 52, for example, the following is used. 19 to 22 are explanatory views showing the structure of a conventional flexible substrate 52 connected to the FPC connector 50. FIG. FIG. 19 is a plan view showing an outline of the flexible substrate 52, and is shown by a broken line in a state where a part of the configuration is seen through for explanation. 20 is a schematic view showing a QQ cross section of FIG. FIG. 21 is a plan view showing a first wiring layer 52b of the flexible substrate 52, which will be described later, and shows a state seen from above in FIG. FIG. 22 is a plan view showing a second wiring layer 52d of the flexible substrate 52, which will be described later, and shows a state seen from below in FIG.

  As shown in FIGS. 19 to 22, the flexible substrate 52 is formed by alternately stacking first to third insulating layers and first and second wiring layers. The 1st insulating layer 52a and the 3rd insulating layer 52e are comprised by the coverlay as a protective film, for example. In a predetermined region at the end of the substrate, the third insulating layer 52e is not formed in order to make electrical connection with the FPC connector 50. A reinforcing plate 52f is provided on the upper surface of the first insulating layer 52a in order to prevent damage when the FPC connector 50 is connected.

  As shown in FIGS. 19 and 21, a solid ground layer 52m is formed in the first wiring layer 52b. As shown in FIGS. 19 and 22, a signal line 9 described later is connected as each connection pad for electrical connection with the FPC connector 50 in the vicinity of the substrate end portion of the second wiring layer 52 d. A signal connection pad 52l for connecting to the ground layer and a ground connection pad 52k for connecting the ground layer are provided. Each ground connection pad 52k is connected to a ground layer 52m formed in the first wiring layer 52b by a ground via 52h which is a through via formed through the flexible substrate 52. The second wiring layer 52d is wired with a pair of signal lines 9e and 9f, which are microstrip lines, and is connected to the signal connection pad 52l.

  Further, as the rigid board 53 on which the FPC connector 50 is mounted, for example, the following is used. FIG. 23 is a plan view showing a signal wiring layer 53a provided in the outermost layer of the rigid substrate 53 described later. As shown in FIG. 18, the rigid substrate 53 includes a signal wiring layer 53a, an insulating layer 53b, and a ground layer 53c provided in the outermost layer. The outermost signal wiring layer 53a includes a ground connection pad 53d and a signal connection pad 53e as connection terminals connected to the substrate connection portions 55c of the contacts 55. The ground connection pad 53d is connected to the ground layer 53c by a ground via 53h. The signal connection pad 53e is connected to signal lines 9g and 9h formed as microstrip lines.

  Since the FPC connector 50, the flexible substrate 52, and the rigid substrate 53 have the above-described configurations, in the conventional substrate connection structure shown in FIGS. 17 to 23, the signal line 9 of the flexible substrate 52, the FPC connector 50, and the like. A high-frequency signal current is transmitted through the contact 5 corresponding to the signal line 9 and the signal line 9 of the rigid substrate 53. At this time, the ground layer 52m of the flexible substrate 52, the ground via 52h, the contact 55 corresponding to the ground line of the FPC connector 50, and the ground layer 53c of the rigid substrate 53 have a feedback current for the signal current in a direction opposite to the signal current. Flows.

  In addition to the above, there has been proposed a connector for a flexible substrate that prevents misalignment during mounting of the flexible substrate and improves the holding force of the flexible substrate (for example, Patent Document 1). The connector for a flexible substrate disclosed in Patent Document 1 is flexible by including an elastic support piece that elastically presses and supports the flexible substrate inserted into the housing opening in a state where the housing opening / closing portion is opened. It is intended to prevent misalignment during mounting of the substrate and improve the holding power of the flexible substrate.

Japanese Patent No. 3605586

  However, the conventional FPC connector 50 and the substrate connection structure including the FPC connector 50 described with reference to FIGS. 17 to 23 have the following problems. When a signal current flows from the signal line 9 of the flexible substrate 52 to the signal line 9 of the rigid substrate 53 via the contact 55 of the FPC connector 50, the current flows to the contact 55 as shown by the arrow in FIG. . At this time, the support portion 55d indicated by N becomes a stub in the transmission line, and the characteristic impedance of the transmission line is lowered. Thereby, since the characteristic impedance of the transmission line does not become a predetermined value, there is a problem that the transmission characteristic of the high-frequency signal is deteriorated.

  In addition, the connector for a flexible substrate disclosed in Patent Document 1 is a configuration for preventing misalignment during mounting of the flexible substrate and improving the holding force of the flexible substrate, and improves the transmission characteristics of high-frequency signals. I can't.

  The present invention has been made to solve such a problem, and a connector for a flexible substrate capable of improving the transmission characteristics of a high-frequency signal at a connection portion between the flexible substrate and another substrate, and for the flexible substrate. It is an object of the present invention to provide a substrate connection structure, an optical transceiver module, and an optical transceiver apparatus provided with a connector.

  In order to solve the above-described problems, a flexible board connector according to the present invention includes a housing that accommodates a plurality of contacts at predetermined intervals in an opening into which a flexible board is inserted, and is mounted on a printed board. In the board connector, each contact is connected to the connecting terminal of the printed board on which the connector for the flexible board is mounted from the inserting board connecting part connected to the connecting terminal of the flexible board inserted into the opening. Up to this point, the protrusion is not formed on the transmission line.

  In the flexible board connector according to the present invention, the contact connecting the connection terminal of the flexible board inserted into the flexible board connector and the connection terminal of the printed board on which the flexible board connector is mounted. A high frequency signal is transmitted.

  Here, the contact does not form a protruding portion with respect to the transmission line from the insertion board connection portion connected to the connection terminal of the flexible board to the mounting board connection portion connected to the connection terminal of the printed board. For this reason, since the location which becomes a stub does not exist in the transmission line of a signal, the fall of the characteristic impedance of a transmission line is suppressed.

  In order to solve the above-described problems, a board connection structure according to the present invention includes a housing that houses a flexible board and a printed board at a predetermined interval in a plurality of contacts in an opening into which the flexible board is inserted. In the board connection structure that is electrically connected using the flexible board connector mounted on the top, each contact of the flexible board connector is connected to the connection terminal of the flexible board inserted into the opening. To the mounting board connection part connected to the connection terminal of the printed circuit board, the protruding part is not formed with respect to the transmission line.

  In the flexible board connector of the board connection structure according to the present invention, the connection between the connection terminal of the flexible board inserted into the flexible board connector and the connection terminal of the printed board on which the flexible board connector is mounted is connected. A high frequency signal is transmitted through the contact.

  Here, the contact does not form a protruding portion with respect to the transmission line from the insertion board connection portion connected to the connection terminal of the flexible board to the mounting board connection portion connected to the connection terminal of the printed board. For this reason, since the location which becomes a stub does not exist in the transmission line of a signal, the fall of the characteristic impedance of a transmission line is suppressed.

  In order to solve the above-described problems, an optical transmission / reception module according to the present invention includes an optical transmission / reception circuit board, an optical transmission module connected to the optical transmission / reception circuit board, which converts an electrical signal into an optical signal and outputs the optical signal. In an optical transceiver module comprising an optical receiver module that converts a signal into an electrical signal and outputs the optical signal, the optical transceiver circuit board is mounted on another board via a flexible board having a microstrip line in the outermost signal wiring layer. The flexible board connector is provided with a housing that accommodates a plurality of contacts at predetermined intervals in an opening into which the flexible board is inserted, and each contact is inserted into the opening. Mounting board connected to connecting terminal of other board from connecting part of connecting board connected to connecting terminal of flexible board To the connecting portion, and is characterized in that it has a non-form protrusions against the transmission line.

  In the flexible substrate connector of the optical transceiver module according to the present invention, the connection between the connection terminal of the flexible substrate inserted into the flexible substrate connector and the connection terminal of the other substrate on which the flexible substrate connector is mounted is connected. A high frequency signal is transmitted through the contact.

  Here, the contact does not form a protruding portion with respect to the transmission line from the insertion board connection portion connected to the connection terminal of the flexible board to the mounting board connection portion connected to the connection terminal of the printed board. For this reason, since the location which becomes a stub does not exist in the transmission line of a signal, the fall of the characteristic impedance of a transmission line is suppressed.

  In order to solve the above-described problems, an optical transmission / reception apparatus according to the present invention includes an optical transmission / reception circuit board, an optical transmission module connected to the optical transmission / reception circuit board, which converts an electrical signal into an optical signal and outputs the optical signal. In an optical transmission / reception apparatus comprising an optical transmission / reception module having an optical reception module for converting an electrical signal into an electrical signal and a parent substrate to which the optical transmission / reception module is connected, the optical transmission / reception circuit board is an outermost signal wiring layer Are electrically connected to a flexible board connector mounted on a parent board through a flexible board having a microstrip line, and the flexible board connector has a plurality of contacts in an opening into which the flexible board is inserted. Each contact is connected to the connection terminal of the flexible board inserted in the opening That from the insertion board connecting portion, to the mounting board connecting portion connected to the connection terminals of the printed circuit board, it is characterized in that it has a non-form protrusions against the transmission line.

  In the flexible board connector of the optical transceiver according to the present invention, the connection between the connection terminal of the flexible board inserted into the flexible board connector and the connection terminal of the parent board on which the flexible board connector is mounted is connected. A high frequency signal is transmitted through the contact.

  Here, the contact does not form a protruding portion with respect to the transmission line from the insertion board connection portion connected to the connection terminal of the flexible board to the mounting board connection portion connected to the connection terminal of the printed board. For this reason, since the location which becomes a stub does not exist in the transmission line of a signal, the fall of the characteristic impedance of a transmission line is suppressed.

  According to the connector for a flexible board according to the present invention, the contact protrudes from the insertion board connection part connected to the connection terminal of the flexible board to the mounting board connection part connected to the connection terminal of the printed board with respect to the transmission line. Therefore, the transmission line does not have a portion that becomes a stub, and a decrease in the characteristic impedance of the transmission line can be suppressed. Thereby, it becomes possible to improve the transmission characteristic of the high frequency signal in the connection location of a flexible substrate and a printed circuit board.

  According to the board connection structure of the present invention, the contact of the flexible board connector is connected to the transmission line from the insertion board connection part connected to the connection terminal of the flexible board to the mounting board connection part connected to the connection terminal of the printed board. On the other hand, since the projecting portion is not formed, there is no portion that becomes a stub in the transmission line, and a decrease in characteristic impedance of the transmission line is suppressed. Thereby, it becomes possible to improve the transmission characteristic of the high frequency signal in the connection location of a flexible substrate and a printed circuit board.

  According to the optical transceiver module of the present invention, the contact of the connector for the flexible board is connected to the transmission line from the insertion board part connected to the connection terminal of the flexible board to the mounting board connection part connected to the connection terminal of the other board. Thus, since the projecting portion is not formed, there is no portion that becomes a stub in the transmission line, and a decrease in the characteristic impedance of the transmission line is suppressed. Thereby, the transmission characteristic of the high frequency signal in the connection part of a flexible substrate and another board | substrate can be improved, and it becomes possible to perform transmission and reception of high-speed data stably.

  According to the optical transmission / reception apparatus according to the present invention, the contact of the connector for the flexible board is connected to the transmission line from the insertion board connection part connected to the connection terminal of the flexible board to the mounting board connection part connected to the connection terminal of the parent board. On the other hand, since the projecting portion is not formed, there is no portion that becomes a stub in the transmission line, and a decrease in characteristic impedance of the transmission line is suppressed. Thereby, the transmission characteristic of the high frequency signal in the connection part of a flexible substrate and another board | substrate can be improved, and it becomes possible to perform transmission and reception of high-speed data stably.

  Embodiments of a flexible board connector, a board connection structure, an optical transmission / reception module, and an optical transmission / reception apparatus according to the present invention will be described below with reference to the drawings. First, an embodiment of a flexible board connector and a board connection structure provided with the flexible board connector of the present invention will be described.

<Configuration Example of Flexible Board Connector / Board Connection Structure of the Present Embodiment>
FIG. 1 to FIG. 3 are explanatory views showing a flexible board connector (hereinafter referred to as an FPC (Flexible Printed Circuit) connector 1) and a board connection structure including the FPC connector 1 according to the present embodiment. FIG. 1 is a cross-sectional view showing a board connection structure provided with an FPC connector 1 and shows a state where the board is mounted on a rigid board 3 to be described later. FIG. 1 shows a state in which a later-described housing opening / closing portion 4a is opened with a later-described flexible substrate 2 inserted. FIG. 2 is a perspective view showing an outline of the FPC connector 1, and shows a state in which a housing opening / closing portion 4a described later is opened. FIG. 3 is a cross-sectional view showing a board connection structure provided with the FPC connector 1 and shows a state where it is mounted on a rigid board 3 to be described later. FIG. 3 shows a state in which a later-described housing opening / closing portion 4a is closed with a later-described flexible substrate 2 inserted. 1 and 3, the rigid substrate 3 shows a partial configuration.

  As shown in FIGS. 1 to 3, the FPC connector 1 includes a housing 4 having a housing opening 4b that is opened and closed by a housing opening and closing portion 4a. Inside the housing 4, contacts 5 made of metal integrally formed with an FPC connection portion 5 a and a lead portion 5 b connected to the connection terminal of the flexible substrate 2 are accommodated in parallel at a predetermined interval. The housing opening / closing part 4a is an example of a pressure member, and the housing opening 4b is an example of an opening.

  The FPC connection portion 5a is formed to protrude in the horizontal direction from the lead portion 5b. In addition, a substrate connection portion 5 c connected to a connection terminal of the rigid substrate 3 is provided at the end of the lead portion 5 b of the contact 5. As shown in FIGS. 1 and 3, the contact 5 of the FPC connector 1 does not form a protruding portion like the support portion 55d of the contact 55 of the conventional FPC connector 50 shown in FIG. Up to the substrate connection portion 5c, it is formed in a single stroke. The FPC connection part 5a is an example of an insertion board connection part, and the board connection part 5c is an example of a mounting board connection part.

  As shown in FIG. 3C, the housing 4 and the contact 5 have complementary irregularities, and are fixed in a state of being fitted to each other by the irregularities. Thus, the strength of the housing 4 and the contact 5 is maintained without providing the support portion insertion portion 54d and the support portion 55d, respectively, like the housing 54 and the contact 55 of the conventional FPC connector 50 shown in FIG. It becomes possible to fix.

  The FPC connection portion 5 a is located in a connection portion receiving groove 4 c provided in the lower portion of the housing opening 4 b of the housing 4. The end portion of the FPC connection portion 5a connected to the connection terminal of the flexible substrate is in a state of protruding a predetermined amount from the connection portion receiving groove 4c.

  With the housing opening / closing part 4a open as shown in FIG. 1, the flexible substrate 2 is inserted into the housing opening 4b with the connection terminal on the bottom, and the housing opening / closing part 4a is closed as shown in FIG. The substrate 2 is pressed downward by the housing opening / closing portion 4a, and the connection terminal of the flexible substrate 2 and the FPC connection portion 5a of the contact 5 are in contact with each other as shown in FIG. Further, as shown in FIG. 3D, the board connecting portion 5c of the contact 5 is connected to the connecting terminal of the rigid board 3 by soldering.

  Here, for example, the following is used as the flexible substrate 2. 4 to 8 are explanatory diagrams illustrating examples of the configuration of the flexible substrate 2. FIG. 4 is a plan view illustrating the outline of the flexible substrate 2, and is illustrated by a broken line in a state where a part of the configuration is seen through for explanation. FIG. 5 is a schematic view showing an EE cross section of FIG. 6 is a plan view showing a first wiring layer 2b of the flexible substrate 2 to be described later, and shows a state seen from above in FIG. 7 and 8 are plan views showing a second wiring layer 2d of the flexible substrate 2 to be described later, and show a state seen from below in FIG. 7 shows portions corresponding to FIGS. 4 and 6, and FIG. 8 shows a state in which the left-right direction of FIG. 7 is elongated.

  As shown in FIGS. 4 to 8, the flexible substrate 2 is formed by alternately stacking first to third insulating layers and first and second wiring layers. The first and second wiring layers are formed of a metal film such as CCL (Copper Clad Laminate), for example. The first to third insulating layers are made of an epoxy or polyimide resin. The 1st insulating layer 2a and the 3rd insulating layer 2e are comprised by the coverlay as a protective film, for example. In a predetermined region at the end of the substrate, the third insulating layer 2e is not formed in order to make electrical connection with the FPC connector 1. A reinforcing plate 2f is provided on the upper surface of the first insulating layer 2a in order to prevent damage during connection to the FPC connector 1.

  As shown in FIGS. 4 and 6, signal lines 9a and 9b are formed as microstrip lines in the first wiring layer 2b. Further, at the end of the second wiring layer 2d, a signal connection pad 21 for electrical connection between the FPC connector 1 and each signal line 9, and a ground connection pad for connection between the FPC connector 1 and the ground layer. 2k is formed. Further, as shown in FIGS. 4, 7, and 8, a ground layer 2m is formed in the second wiring layer 2d. As shown by L16 in FIG. 8, the ground layer 2m is formed to have a predetermined width at locations corresponding to the signal lines 9a and 9b. The width of the ground layer 2m indicated by L16 is determined in consideration of the influence on the surroundings due to the resonance of the ground layer 2m. The signal connection pad 21 is an example of a signal connection terminal.

  The signal line 9 of the first wiring layer 2b and the signal connection pad 21 of the second wiring layer 2d are connected by a signal via 2g that is a through via formed through the flexible substrate 2. The signal line 9 and the signal connection pad 21 are connected by, for example, three or more signal vias 2g in order to reduce the potential difference between them. The signal via 2g is an example of a signal wiring via.

  Further, as shown in FIG. 6, a ground guard portion 2i is formed at a location corresponding to the position of the ground connection pad 2k in order to prevent external noise intrusion and interference between the signal lines. In order to form the ground guard portion 2i, the ground layer 2m formed on the first wiring layer 2b and the second wiring layer 2d is connected by the ground via 2h at a location corresponding to the ground connection pad 2k. In order to reduce the potential difference between the first wiring layer 2b and the second wiring layer 2d of the ground guard portion 2i, the two are connected by, for example, three or more ground vias 2h. The ground via 2h is an example of a flexible substrate ground wiring via.

  As shown in FIGS. 4 and 6, the signal lines 9a and 9b include a flexible substrate signal taper portion 2j formed so that the line width gradually increases toward the signal via 2g in the vicinity of the signal via 2g. Further, as shown in FIGS. 4 and 7, the ground layer 2m of the second wiring layer 2d extends from the portion corresponding to the ground connection pad 2k toward the wiring direction of the signal lines 9a and 9b. A ground layer taper portion 2o formed in accordance with the shape of the flexible substrate signal taper portion 2j is provided. The flexible substrate signal taper portion 2j is an example of a taper portion provided in the microstrip line of the flexible substrate, and the ground layer taper portion 2o is a taper portion provided in the ground conductor layer corresponding to the microstrip line of the flexible substrate. It is an example.

  Further, as the rigid substrate 3, for example, the following is used. FIG. 9 is a plan view showing a signal wiring layer 3a provided in the outermost layer of the rigid substrate 3 to be described later. As shown in FIGS. 1 and 3, the rigid substrate 3 includes a signal wiring layer 3a, an insulating layer 3b, and a ground layer 3c provided in the outermost layer. The outermost signal wiring layer 3 a includes ground connection pads 3 d and signal connection pads 3 e as connection terminals connected to the substrate connection portions 5 c of the contacts 5. The ground connection pad 3d is connected to the ground layer 3c by a ground via 3i.

  The signal connection pad 3e is connected to signal lines 9c and 9d formed as microstrip lines. Here, the signal lines 9c and 9d include a rigid substrate signal taper portion 3f formed so that the line width gradually increases toward the signal connection pad 3e in the vicinity of the signal connection pad 3e. The rigid substrate signal taper portion 3f is an example of a taper portion provided in the microstrip line of the rigid substrate.

  Further, as shown in FIGS. 1, 3, and 8, the signal wiring layer 3 a of the rigid substrate 3 is positioned at a position corresponding to the contact 5 of the FPC connector 1 that connects the signal lines 9 of the flexible substrate 2 and the rigid substrate 3. A ground plane 3g having a predetermined size is provided. The ground surface 3g is connected to the ground layer 3c of the rigid substrate 3 by a ground via 3h that is a through via formed through the rigid substrate 3. In order to reduce the potential difference between the ground plane 3g and the ground layer 3c, the ground plane 3g and the ground layer 3c are connected by, for example, three or more ground vias 3h. The ground surface 3g is an example of a ground conductor portion connected to the ground conductor layer of the printed circuit board, and the ground via 3h is an example of a printed circuit board ground wiring via.

  The board connection structure provided with the FPC connector 1 shown in FIGS. 1 to 3 includes the flexible board 2 shown in FIGS. 4 to 8 and the rigid board 3 shown in FIGS. 1, 3, and 8. However, the FPC connector 1 shown in FIGS. 1 to 3 and the flexible board 52 shown in FIGS. 19 to 22 or the rigid board 53 shown in FIG. 23 may be provided.

  Furthermore, in the board connection structure provided with the FPC connector 1 of the present embodiment shown in FIGS. 1 to 9, a single-end mode signal may be transmitted by one signal line 9. The differential signal may be transmitted by the signal line 9.

<Operation example of connector / board connection structure for flexible board of this embodiment>
Next, an operation example of the FPC connector 1 of the present embodiment and the board connection structure provided with the FPC connector 1 will be described. In the substrate connection structure of the present embodiment shown in FIGS. 1 to 9, signals are transmitted by the signal lines 9a and 9b of the flexible substrate 2, the signal vias 2g, the contacts 5 of the FPC connector 1, and the signal lines 9c and 9d of the rigid substrate. Is transmitted.

  When a signal current flows from the signal line 9 of the flexible substrate 2 to the signal line 9 of the rigid substrate 3 via the contact 5 of the FPC connector 1, the current flows to the contact 5 as shown by an arrow in FIG. 3. . In the contact 5 of the FPC connector 1, since there is no portion that becomes a stub in the transmission line, unlike the support portion 55 d of the contact 55 of the conventional FPC connector 50 shown in FIG. 18, a decrease in characteristic impedance of the transmission line can be suppressed. As a result, it is possible to prevent the transmission characteristic of the high-frequency signal from being lowered due to the characteristic impedance of the transmission line not reaching a predetermined value, and to improve the transmission characteristic of the high-frequency signal at the connection point between the flexible substrate 2 and the rigid substrate 3. Become.

  Moreover, in the board | substrate connection structure of this Embodiment, as shown in FIG. 3, the 1st wiring layer 2b with which the signal track | line 9 of the flexible substrate 2 is provided is reverse with respect to the rigid board | substrate 3 with which the FPC connector 1 is mounted. Located on the side. For this reason, the signal line 9 is mainly coupled to the ground layer 2m provided in the second wiring layer 2d of the flexible substrate 2 and is not coupled to the ground layer 3c provided in the rigid substrate 3 shown in A. For this reason, the signal line 9 on the flexible substrate 2 and the ground layer 3c of the rigid substrate 3 are coupled to generate capacitance, thereby preventing a decrease in the characteristic impedance of the signal line 9, and the high-frequency signal transmission characteristic. Decline can be prevented.

  FIG. 10 is a plan view showing the flow of a signal current and a feedback current when a high-frequency signal is transmitted through the signal lines 9a and 9b of the flexible substrate 2 of the substrate connection structure of the present embodiment. FIG. 10 shows the signal lines 9a and 9b provided on the first wiring layer 2b of the flexible substrate 2 and the ground layer 2m provided on the second wiring layer 2d. When a high-frequency signal is transmitted to the signal lines 9a and 9b of the flexible substrate 2, current flows through the signal lines 9a and 9b as indicated by an arrow F in FIG. At this time, a feedback current flows through the ground layer 2m as indicated by an arrow G in FIG.

  Here, in the substrate connection structure of the present embodiment, the signal lines 9a and 9b provided in the first wiring layer 2b of the flexible substrate 2 are gradually widened toward the signal via 2g in the vicinity of the signal via 2g. The flexible substrate signal taper portion 2j is formed. In addition, a ground layer taper portion 2o is formed in the vicinity of the ground connection pad 2k of the second wiring layer 2d in a direction that matches the flexible substrate signal taper portion 2j of the signal line 9.

  For this reason, the coupling of the ground layer 2m of the second wiring layer 2d with the signal lines 9a and 9b in the vicinity of the connection portion between the signal lines 9a and 9b and the signal via 2g can be strengthened, and the characteristic impedance of the transmission line is drastically increased. Change is suppressed. Furthermore, as shown by an arrow G in FIG. 10, a rapid change in the path of the feedback current is suppressed in the vicinity of the ground connection pad 2k. Thereby, it becomes possible to improve the transmission characteristic of the high frequency signal in the connection location of the flexible substrate 2 and the FPC connector 1.

  In the substrate connection structure of the present embodiment, the signal lines of the flexible substrate 2 and the rigid substrate 3 are connected in the signal wiring layer 3a of the rigid substrate 3 as shown in FIGS. A ground surface 3g having a predetermined size connected to the ground layer 3c is provided at a position corresponding to the contact 5 of the FPC connector 1. For this reason, by increasing the coupling between the connection terminal of the flexible substrate 2 and the FPC connection portion 5a of the contact 5 and the ground, an increase in the value of the characteristic impedance can be suppressed. Further, since the ground plane 3g and the ground layer 3c are connected by the three ground vias 3h, the potential of the ground plane 3g is stabilized, and adverse effects on the high-frequency characteristics of the transmission line due to resonance and the like are suppressed.

  Furthermore, in the substrate connection structure of the present embodiment, the signal lines 9c and 9d provided in the signal wiring layer 3a of the rigid substrate 3 gradually become wider toward the signal connection pad 3e in the vicinity of the signal connection pad 3e. A rigid substrate signal taper portion 3f formed as described above is provided. For this reason, a rapid change in the characteristic impedance of the transmission line in the vicinity of the connection portion between the signal lines 9a and 9b and the signal connection pad 3e can be suppressed. As a result, it is possible to improve the transmission characteristics of high-frequency signals at the connection point between the FPC connector 1 and the rigid board 3.

  As described above, in the board connection structure including the FPC connector 1 and the FPC connector 1 according to the present embodiment, it is possible to improve the transmission characteristics of the high frequency signal at the connection place of the flexible board 2 and the rigid board 3.

  Next, the measurement results of the reflection loss (S11) and the transmission loss (S12) in the board connection structure including the FPC connector 1 of the present embodiment and the board connection structure including the conventional FPC connector 50 will be described. 11 shows signal lines at each frequency of the board connection structure including the FPC connector 1 of the present embodiment shown in FIGS. 1 to 9 and the board connection structure including the conventional FPC connector 50 shown in FIGS. 9 is a diagram illustrating a measurement result of a reflection loss (S11) of a signal current on N. H indicates the measurement result of the substrate connection structure of the present embodiment, and I indicates the measurement result of the conventional substrate connection structure.

  12 shows signal lines at each frequency of the board connection structure including the FPC connector 1 of the present embodiment shown in FIGS. 1 to 9 and the board connection structure including the conventional FPC connector 50 shown in FIGS. 9 is a diagram illustrating a measurement result of a transmission loss (S12) of a signal current on No. 9. FIG. J shows the measurement result of the board connection structure of the present embodiment, and K shows the measurement result of the conventional board connection structure.

  The dimensions of each part in each measurement result are as follows. In the flexible substrate 2 having the substrate connection structure of the present embodiment, the diameter of the signal via 2g and the ground via 2h is 0.25 mm, and the interval between the signal via 2g and the ground via 2h indicated by L4 and L5 in FIG. 725 mm. The length indicated by L7 is 0.95 mm, and the length indicated by L8 is 0.65 mm. Further, the length indicated by L1 and L2 is 0.5 mm, the length indicated by L3 is 2.0 mm, the length indicated by L26 is 0.25 mm, and the length indicated by L5 is 3.0 mm. is there.

  Further, in the flexible substrate 2 of the substrate connection structure of the present embodiment, the width of the signal connection pad 21 shown in L11 of FIG. 7 is 0.95 mm, and the width of the ground connection pad 2k shown in L13 is 0.65 mm. . Furthermore, the length indicated by L9 is 0.35 mm, the length indicated by L10 is 0.1025 mm, and the length indicated by L12 is 1.35 mm. In FIG. 8, the length indicated by L14 is 1.5 mm, the length indicated by L15 is 2.0 mm, and the length indicated by L16 is 2.5 mm.

  In the flexible substrate 2 having the substrate connection structure of the present embodiment, the second insulating layer 2c is made of a polyimide resin, the relative dielectric constant is 3.2, and the tan δ is 0.005. is there. The thickness of the substrate is 0.05 mm, and the characteristic impedance value is controlled to 50Ω.

  Further, in the rigid substrate 3 having the substrate connection structure of the present embodiment, the width of the ground surface 3g shown in L17 of FIG. 9 is 0.6 mm, the length of the ground surface 3g shown in L18 is 2 mm, The distance between the centers of the ground surfaces 3g shown is 2 mm. The distance between the centers of the ground connection pad 3d and the signal connection pad 3e indicated by L20 is 1 mm, the widths of the ground connection pad 3d and the signal connection pad 3e indicated by L21 and L22 are 0.3 mm, and L23 and L25. The length indicated by is 1.5 mm. Further, the length indicated by L24 is 0.3 mm.

  Furthermore, in the rigid substrate 3 of the substrate connection structure of the present embodiment, the insulating layer 3b is composed of FR4 (Flame Retardant Type 4), the relative permittivity value is 4.4, and the tan δ value is 0.02. It is. The thickness of the substrate is 0.15 mm, the thickness of the copper foil is 0.03 mm, and the characteristic impedance value is controlled to 50Ω.

  Further, the distance between the contacts 5 of the FPC connector 1 is 1 mm, the material of the housing 4 is polyamide, the relative dielectric constant is about 3.8, and the tan δ is 0.01.

  In order to perform stable transmission of a high-speed signal, it is necessary that the reflection loss (S11) of the transmission line is −10 dB or less and the transmission loss (S21) is −3 dB or more at the frequency of the transmission data rate. Is done. As shown in FIGS. 11 and 12, in the substrate connection structure of the present embodiment, the reflection loss is a value of −23 dB or less and the transmission loss is a value of −0.2 dB or more at 10 GHz. Therefore, in the substrate connection structure of the present embodiment, high-speed serial transmission at 10 Gbps can be stably performed. As described above, the FPC connector 1 of the present embodiment and the board connection structure including the FPC connector 1 can improve the transmission characteristics of the high-frequency signal at the connection place between the flexible board 2 and the rigid board 3. Can be confirmed.

  Next, as an embodiment of an optical transceiver module and an optical transceiver apparatus according to the present invention, an optical transceiver module and a network card using a board connection structure provided with the FPC connector 1 of the present embodiment will be described.

<Configuration example of optical transceiver module and network card of this embodiment>
FIGS. 13 to 16 are explanatory diagrams showing configurations of the optical transceiver module 19 and the network card 20 of the present embodiment. FIG. 13 is a plan view schematically showing a first example of the optical transceiver module 19 and the network card 20 of the present embodiment, and FIG. 14 is a first diagram of the optical transceiver module 19 and the network card 20 of the present embodiment. It is sectional drawing which shows the outline of an example. 15 is a plan view showing an outline of a second example of the optical transceiver module 19 and the network card 20, and FIG. 16 is a cross-sectional view showing an outline of a second example of the optical transceiver module 19 and the network card 20. 14 and 16, the bezel 24 described later is not shown.

  The network card 20 of the present embodiment includes an optical transmission / reception module 19 and is mounted in an expansion slot of a personal computer or the like, and is connected to an external information communication device or the like through an optical cable connected to an optical cable connection connector 33 described later. Data can be transmitted and received. The optical transceiver module 19 and the network card 20 are configured as follows, for example.

  As shown in FIGS. 13 to 16, the network card 20 includes an optical transmission / reception module 19 having an optical cable connector 33, an optical transmission / reception board connection FPC 21, a host board 23 having an optical transmission / reception circuit unit B22, and end portions of the host board 23. It is comprised with the bezel 24 attached to. The optical transceiver module 19 is attached to the host board 23 so that the optical cable connector 33 protrudes from the bezel 24. The host board 23 has a card edge portion 25, and the network card 20 can be mounted in an expansion slot of a personal computer or the like by the card edge portion 25.

  The optical transmission / reception module 19 includes an optical transmission / reception board 32 having an optical transmission / reception module housing 26, a TOSA 27, a ROSA 28, a TOSA connection FPC 30, a ROSA connection FPC 29, and an optical transmission / reception circuit unit A31.

  The TOSA 27 and the ROSA 28 are arranged side by side at positions corresponding to the optical cable connector 33 of the optical transceiver module housing 26. A TOSA (Transmitter Optical Sub-Assembly) 27 is an optical device for transmission having a laser diode or the like, and has an interface to an optical cable connector connected to the optical cable connector 33, and converts an electrical signal into an optical signal. Output. The TOSA 27 is an example of an optical transmission module. The ROSA (Receiver Optical Sub-Assembly) 28 is a receiving optical device including a photodiode or the like, and has an interface to an optical cable connector connected to the optical cable connector 33, and converts an optical signal into an electrical signal. Output. The ROSA 28 is an example of an optical receiving module.

  The TOSA 27 and the ROSA 28 are connected to the optical transmission / reception board 32 by a TOSA connection FPC 30 and a ROSA connection FPC 29, respectively. The optical transmission / reception board 32 includes a rigid substrate, and includes an optical transmission / reception circuit unit A31 connected to the TOSA 27 and the ROSA 28 via the TOSA connection FPC 30 and the ROSA connection FPC 29. The optical transmission / reception circuit unit A31 includes, for example, a driving circuit for a laser diode of TOSA 27, a post-amplifier circuit for a signal received by a photodiode of ROSA 28, and the like.

  The optical transmission / reception board 32 is connected to the host board 23 via the optical transmission / reception board connection FPC 21. As a result, each circuit of the optical transmission / reception circuit unit A31 is connected to each circuit of the optical transmission / reception circuit unit B22 via the optical transmission / reception board connection FPC 21. The optical transceiver circuit unit B22 includes, for example, a PHY (Physical layer) chip, a MAC (Media Access Control) chip, and the like. The optical transceiver board 32 is an example of an optical transceiver circuit board, and the host board 23 is an example of a parent board.

  The optical transceiver module 19 of the first example shown in FIG. 13 and FIG. 14 is an FPC 30 for TOSA connection, an FPC 29 for ROSA connection, an FPC 21 for optical transceiver board connection, and an optical transceiver board 32 are M in FIG. 13 and FIG. Soldering is performed at a connection portion of each substrate shown. Therefore, each substrate is manufactured separately as compared with the case where the FSA 30 for TOSA connection, the FPC 29 for ROSA connection, the FPC 21 for optical transmission / reception board connection, and the optical transmission / reception board 32 are integrally formed. Is possible. Therefore, each substrate can be manufactured at low cost. Further, since each substrate is manufactured separately, for example, even when a design change occurs only in the optical transmission / reception board connection FPC 21, only the manufacturing process of the optical transmission / reception board connection FPC 21 may be changed. Can be kept within a small range.

  15 and FIG. 16, the optical transceiver module 19 of the second example includes a FPC 30 for TOSA connection, an FPC 29 for ROSA connection, an FPC 21 for optical transceiver board connection, and an optical transceiver board 32 configured by a flex rigid board. . This eliminates the need for soldering work during manufacturing, as compared with the configuration in which the flexible substrates of the TOSA connection FPC 30, the ROSA connection FPC 29, and the optical transmission / reception board connection FPC 21 are soldered to the optical transmission / reception board 32. Therefore, the manufacturing operation time can be shortened, and further, it is possible to prevent the occurrence of defective manufacturing due to bad soldering work and adverse effects on surrounding components due to heat during the soldering work.

  Further, the optical transceiver module 19 and the network card 20 of the present embodiment shown in FIGS. 13 to 16 are connected to an optical transceiver board connecting FPC 21 by an FPC connector 34 provided on the host board 23. As a result, it is possible to easily attach the optical transceiver board connecting FPC 21 to the host board 23. Here, the substrate connection structure including the FPC connector 1 of the present embodiment described with reference to FIGS. 1 to 9 is applied to the optical transmission / reception board connection FPC 21, the host board 23, and the FPC connector 34.

  In the optical transceiver module 19 and the network card 20 of the present embodiment, the TOSA 27, the ROSA 28, the optical transceiver board 32, and the host board 23 are connected by a flexible substrate. Accordingly, the arrangement of each member can be changed within the range of the length of each flexible substrate. For example, the optical transceiver module housing in which the optical transceiver board 32 is attached after each member is connected by the flexible substrate. It is possible to adjust the position in order to align the end face of this with the position of the bezel 24.

  Furthermore, in the optical transmission / reception module 19 and the network card 20 of the present embodiment, each module and part of the circuit for performing optical transmission / reception are configured as an optical transmission / reception module. This makes it possible to share the specifications of the optical transmission / reception module such as another network card with the optical transmission / reception module, and to use the optical transmission / reception module having the same specifications as the optical transmission / reception apparatus such as another network card. As a result, the design and manufacturing costs can be reduced.

<Operation example of optical transceiver module and network card of this embodiment>
Next, operation examples of the optical transceiver module 19 and the network card 20 described with reference to FIGS. 13 to 16 will be described. The optical transmission / reception module 19 and the network card 20 are mounted in an expansion slot of a personal computer or the like, and transmit / receive data to / from an external information communication device or the like through an optical cable connected to the optical cable connector 33 as shown below. .

  Data transmission to an external information communication device or the like is performed as follows. Information necessary for data transmission is input as an electrical signal to the optical transmission / reception circuit unit B22 via the card edge unit 25 connected to an expansion slot of a personal computer or the like. Information necessary for data transmission input to the optical transmission / reception circuit unit B22 as an electrical signal is processed by the MAC chip, the PHY chip, and the like, and the light on the optical transmission / reception board 32 is transmitted via the optical transmission / reception board connection FPC 21. An electric signal is input to the transmission / reception circuit unit A31. Thereafter, based on the information input to the optical transmission / reception circuit unit A31, the laser diode of the TOSA 27 is driven by an electrical signal via the TOSA connection FPC 30, and data is transmitted as an optical signal to an external information communication device through an optical cable. Is done.

  Reception of data from an external information communication device or the like is performed as follows. Data from an external information communication device is input to the photodiode of ROSA 28 as an optical signal through an optical cable. The optical signal input to the photodiode of the ROSA 28 is converted into an electrical signal and input to the optical transmission / reception circuit unit A31 on the optical transmission / reception board 32 via the ROSA connection FPC 29 as an electrical signal. The electrical signal input to the optical transmission / reception circuit unit A31 is processed by a post-amplifier circuit or the like, and then input to the optical transmission / reception circuit unit B22 on the host board 23 via the optical transmission / reception board connection FPC 21. The electrical signal input to the optical transmission / reception circuit unit B22 is processed by the PHY chip, the MAC chip, and the like, and is output as received data to the personal computer or the like via the card edge unit 25.

  As described above, when data is transmitted / received to / from an external information communication device through an optical cable, the TOPC connection FPC 30, the ROSA connection FPC 29, the optical transmission / reception board connection FPC 21, the optical transmission / reception board 32, and the host board 23. A high-frequency electric signal is transmitted at each of the signal lines and the joints of the substrates. For example, when high-speed serial data transmission such as 10 Gbit / sec is performed, it is necessary to cope with a high-frequency signal exceeding 10 GHz.

  In the optical transceiver module 19 and the network card 20 of the present embodiment, the FPC connector 1 of the present embodiment described with reference to FIGS. 1 to 9 is used for the optical transceiver board connecting FPC 21, the host board 23, and the FPC connector 34. The provided board connection structure is applied. This enables high-quality signal transmission even when high-frequency signals are transmitted at the connection point between the optical transmission / reception board connection FPC 21 and the host board 23 by performing high-speed data transmission / reception, Stable data transmission / reception is possible.

  The present invention is applied to a flexible substrate connector for connecting a flexible substrate and another substrate, a substrate connection structure including the flexible substrate connector, an optical transmission / reception module, and an optical transmission / reception device.

It is sectional drawing of the FPC connector and board | substrate connection structure of this Embodiment. It is a perspective view of the FPC connector of this Embodiment. It is sectional drawing of the FPC connector and board | substrate connection structure of this Embodiment. It is a top view of the flexible substrate of the board | substrate connection structure of this Embodiment. It is sectional drawing of the flexible substrate of the board | substrate connection structure of this Embodiment. It is a top view of the flexible substrate of the board | substrate connection structure of this Embodiment. It is a top view of the flexible substrate of the board | substrate connection structure of this Embodiment. It is a top view of the flexible substrate of the board | substrate connection structure of this Embodiment. It is a top view of the rigid board | substrate of the board | substrate connection structure of this Embodiment. It is a top view of the flexible substrate of the board | substrate connection structure of this Embodiment. It is a measurement result of reflection loss. It is a measurement result of transmission loss. It is a top view of the optical transmission / reception module and network card | curd of a 1st example. It is sectional drawing of the optical transmission / reception module and network card | curd of a 1st example. It is a top view of the optical transmission / reception module and network card | curd of a 2nd example. It is sectional drawing of the optical transmission / reception module and network card | curd of a 2nd example. It is a perspective view of the conventional FPC connector. It is sectional drawing of the conventional FPC connector and board | substrate connection structure. It is a top view of the flexible substrate of the conventional board | substrate connection structure. It is sectional drawing of the flexible substrate of the conventional board | substrate connection structure. It is a top view of the flexible substrate of the conventional board | substrate connection structure. It is a top view of the flexible substrate of the conventional board | substrate connection structure. It is a top view of the flexible substrate of the conventional board | substrate connection structure.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... FPC connector, 2 ... Flexible substrate, 2g ... Signal via, 2h ... Ground via, 2j ... Flexible substrate signal taper part, 2k ... Ground connection pad, 2l ... Signal connection pad, 2m ... ground layer, 2o ... ground layer taper, 3 ... rigid substrate, 3c ... ground layer, 3f ... rigid substrate signal taper, 3g ... ground surface 3h: Ground via, 4 ... Housing, 4a ... Housing opening / closing part, 4b ... Housing opening, 5 ... Contact, 5a ... FPC connection part, 5c ... Board connection 9, signal line, 9 a, signal line, 9 b, signal line, 9 c, signal line, 9 d, signal line, 19, optical transceiver module, 21, light. Transmit / receive board connection FPC, 23 · · · host board, 27 ··· TOSA, 28 ··· ROSA, 29 ··· ROSA connecting FPC, 30 ··· TOSA connection FPC, 32 · · · optical transceiver board

Claims (15)

In the connector for a flexible board, which is provided with a housing that accommodates a plurality of contacts at predetermined intervals in the opening into which the flexible board is inserted, and is mounted on the printed board.
Each of the contacts is from an insertion board connection part connected to the connection terminal of the flexible board inserted into the opening to a mounting board connection part connected to the connection terminal of the printed board on which the flexible board connector is mounted. The flexible board connector is characterized in that no protrusion is formed on the transmission line. The connector for a flexible substrate according to claim 1, wherein the housing and the contact include a concave portion and a convex portion that are fitted to each other. The pressurizing member which is provided so that the said opening part may be opened and closed, and presses the said flexible substrate inserted in the said opening part with respect to the said insertion board | substrate connection part of the said contact is provided. Flexible board connector. A flexible board and a printed board are electrically connected to each other by using a flexible board connector that is mounted on the printed board and includes a housing that houses a plurality of contacts at predetermined intervals in an opening into which the flexible board is inserted. In the board connection structure that connects to
Each of the contacts of the flexible board connector includes a transmission line from an insertion board connecting portion connected to the connecting terminal of the flexible board inserted into the opening to a mounting board connecting portion connected to the connecting terminal of the printed board. The board connection structure is characterized in that no protrusion is formed. The flexible board and the printed board include a microstrip line in the outermost signal wiring layer,
The printed circuit board is formed through the printed circuit board at a location corresponding to a position of the contact connecting the microstrip line of the flexible circuit board and the printed circuit board in a signal wiring layer including the microstrip line. The board connection structure according to claim 4, further comprising a ground conductor portion connected to the ground conductor layer of the printed board by the printed board ground wiring via. The board connection structure according to claim 5, wherein the ground conductor portion provided in the signal wiring layer including the microstrip line of the printed board is connected by a plurality of vias for the printed board ground wiring. . The contacts on both sides of the contacts connecting the microstrip lines of the flexible board and the printed board connect the grounding conductor portions of the flexible board and the printed board, respectively. 5. The substrate connection structure according to 5. The microstrip line of the printed circuit board includes a taper portion formed so that the line width gradually increases toward the connection terminal in the vicinity of the connection terminal of the printed circuit board. The board connection structure described. The flexible substrate includes, as the connection terminal, a signal connection terminal for connecting the microstrip line to the flexible substrate connector on the other outermost layer of the signal wiring layer including the microstrip line, and In a predetermined position with respect to the signal connection terminal, provided with a ground connection terminal for connecting the ground conductor portion with the connector for the flexible substrate,
The microstrip line of the flexible substrate and the signal connection terminal are connected by a signal wiring via formed through the flexible substrate,
The microstrip line of the flexible substrate includes a tapered portion formed so that the line width gradually increases toward the signal wiring via in the vicinity of the signal wiring via,
The grounding conductor portion of the grounding conductor layer corresponding to the microstrip line of the flexible substrate has a position corresponding to the position of the ground connection terminal toward the wiring direction of the microstrip line of the flexible substrate. The board connecting structure according to claim 5, further comprising a tapered portion formed in accordance with the shape of the tapered portion of the microstrip line. The substrate connection structure according to claim 9, wherein the microstrip line and the signal connection terminal of the flexible substrate are connected by a plurality of the signal wiring vias. 6. The board connection structure according to claim 5, wherein a differential signal is transmitted by a pair of microstrip lines formed on the flexible board and the printed board. The signal wiring layer, the ground conductor layer, and the ground connection terminal provided with the microstrip line of the flexible substrate are connected by a flexible substrate ground wiring via formed through the flexible substrate. The board connection structure according to claim 5. The substrate according to claim 12, wherein the signal wiring layer including the microstrip line of the flexible substrate, the ground conductor layer, and the ground connection terminal are connected by a plurality of vias for flexible substrate ground wiring. Connection structure. An optical transmission / reception circuit board, an optical transmission module connected to the optical transmission / reception circuit board for converting an electrical signal into an optical signal and outputting the optical signal, and an optical receiving module for converting the optical signal into an electrical signal and outputting the optical signal are provided. In optical transceiver module,
The optical transceiver circuit board is electrically connected to a flexible board connector mounted on another board via a flexible board having a microstrip line in the outermost signal wiring layer,
The flexible board connector includes a housing that accommodates a plurality of contacts at predetermined intervals in an opening into which the flexible board is inserted.
Each of the contacts has a protruding portion with respect to the transmission line from the insertion board connection portion connected to the connection terminal of the flexible substrate inserted into the opening to the mounting board connection portion connected to the connection terminal of the other substrate. An optical transceiver module that is not formed. Light having an optical transmission / reception circuit board, an optical transmission module connected to the optical transmission / reception circuit board for converting an electrical signal into an optical signal and outputting the optical signal, and an optical receiving module for converting the optical signal into an electrical signal and outputting the electrical signal In an optical transceiver including a transceiver module and a parent substrate to which the optical transceiver module is connected,
The optical transceiver circuit board is electrically connected to a flexible board connector mounted on the parent board via a flexible board having a microstrip line in the outermost signal wiring layer,
The flexible board connector includes a housing that accommodates a plurality of contacts at predetermined intervals in an opening into which the flexible board is inserted.
Each of the contacts has a protruding portion with respect to the transmission line from an insertion board connection portion connected to the connection terminal of the flexible board inserted into the opening to a mounting board connection portion connected to the connection terminal of the printed board. An optical transceiver characterized by not being formed.

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