JP4852979B2 - Flex-rigid board, optical transceiver module and optical transceiver - Google Patents

Description

  The present invention relates to a flex-rigid board in which a flexible board and a rigid board are connected, and an optical transceiver module and an optical transceiver that include the flex-rigid board. Specifically, a flexible substrate is provided by providing an opening in which a ground conductor portion is not formed in a region opposite to the wiring direction of the microstrip line of the rigid substrate in the ground conductor layer corresponding to the microstrip line of the rigid substrate. It is possible to improve the transmission characteristics of the high frequency signal when the wiring is drawn out to the outermost layer of the rigid substrate.

  As a flexible rigid board to which a flexible board having flexibility and a rigid board are connected, generally, a flexible board and a rigid board laminated vertically on a part of the flexible board are used. Is done. Moreover, when transmitting a high frequency signal on a printed circuit board, a printed circuit board having a microstrip line structure is used.

  20 to 25 are explanatory views showing the configuration of a conventional flex-rigid board 50 provided with a pair of microstrip lines for transmitting differential signals. FIG. 20 is a plan view showing an outline of the flex-rigid board 50. For the sake of explanation, a part of the structure is seen through with a broken line. FIG. 21 is a schematic view showing a JJ cross section of FIG. FIG. 22 is a plan view showing a first wiring layer 10 described later, and FIG. 23 is a plan view showing a second wiring layer 5, a fifth wiring layer 8 and a sixth wiring layer 9 described later. FIG. 24 is a plan view showing a third wiring layer 6 to be described later, and FIG. 25 is a plan view showing a fourth wiring layer 7 to be described later, and a boundary between the flexible substrate portion 3 and the rigid substrate portion 4 to be described later for explanation. Is indicated by a broken line.

  As shown in FIGS. 20 and 21, the flex-rigid board 50 includes a flexible board portion 3 composed of only a flexible board, and a rigid board portion 4 in which a rigid board is laminated on top and bottom of a part of the flexible board. . As shown in FIG. 21, the flexible substrate portion 3 is formed by stacking a third wiring layer 6, a third insulating layer 12, and a fourth wiring layer 7 on the top and bottom. The rigid substrate portion 4 is formed by alternately stacking first to sixth wiring layers and first to fifth insulating layers alternately above and below.

  As shown in FIGS. 22 and 24, the first wiring layer 10 and the third wiring layer 6 are wired with a pair of signal lines 15 as microstrip lines as signal wiring layers. Further, as shown in FIGS. 23 and 25, the second wiring layer 5, the fourth wiring layer 7, the fifth wiring layer 8, and the sixth wiring layer 9 are formed with the ground layer 16.

  20 to 25, a pair of signal vias 17 that connect each signal line 15 provided in the first wiring layer 10 and each signal line 15 provided in the third wiring layer 6 are provided. These are arranged on the rigid board portion 4 at a predetermined interval. Furthermore, a pair of ground vias 18 connecting the ground layers 16 of the second wiring layer 5, the fourth wiring layer 7, the fifth wiring layer 8, and the sixth wiring layer 9 are provided in the rigid substrate portion 4. Each ground via 18 is arranged at a position sandwiching a pair of signal vias 17. Each signal via 17 and each ground via 18 are formed as through vias.

  Further, as shown in FIGS. 23 and 25, in each ground layer 16 formed in the second wiring layer 5, the fourth wiring layer 7, the fifth wiring layer 8, and the sixth wiring layer 9, each signal via 17 is provided. Is provided with a ground layer opening 36 in which the ground layer 16 is not formed in a predetermined size.

  With such a configuration, the flex-rigid board 50 transmits a high-frequency signal through the pair of signal lines 15 and the pair of signal vias 17 that are microstrip lines. At this time, a feedback current for the signal current flows through each ground layer 16 and the pair of ground vias 18 in the direction opposite to the signal current. FIG. 26 is a plan view showing the flow of the signal current and the feedback current, and shows the signal line 15 provided in the first wiring layer 10 and the ground layer 16 provided in the second wiring layer 5. In the conventional flex-rigid board 50, when a signal current flows from the signal via 17 to the signal line 15 of the rigid board portion 4 as shown by an arrow M in FIG. The feedback current flows through the five ground layers 16. At this time, since the high-frequency current has a property of flowing through the end portion of the ground layer 16, a part of the feedback current takes a greatly detoured path as indicated by an arrow N.

  In addition to the above, there has been proposed a flex-rigid board that pulls out the wiring on the flexible board to the outer layer of the rigid board without using a through via (for example, see Patent Document 1). The flex-rigid board disclosed in Patent Document 1 has a configuration in which a part of the flexible board in the flexible board part is drawn out to the outer layer of the rigid board part. With such a configuration, the wiring on the flexible substrate can be drawn out to the outer layer of the rigid substrate without using the through via.

JP-A-2005-64129

  However, the conventional flex-rigid board 50 has the following problems. As described with reference to FIG. 26, when a signal current flows through the signal line 15, a part of the feedback current flowing through the ground layer 16 of the second wiring layer 5 takes a largely detoured path. For this reason, the path of the feedback current flowing through the ground layer 16 becomes long, and the transmission characteristics of high-frequency signals are deteriorated.

  In addition, the parasitic capacitance generated between the ground layer 16 of the second wiring layer 5 and the signal via 17 reduces the value of the characteristic impedance of the signal via 17, resulting in mismatched impedance. As a result, the transmission characteristics of high-frequency signals are reduced. It gets worse.

  Further, in the flex-rigid board disclosed in Patent Document 1, when drawing the wiring on the flexible board to the outermost layer of the rigid board, the portion of the flexible board where the wiring is provided is cut, It is necessary to connect to the outer layer by soldering. For this reason, when there are many wirings to be drawn to the outer layer of the rigid substrate, the advantage of using the flex rigid substrate in which the flexible substrate and the rigid substrate are integrally formed is lost.

  The present invention has been made to solve such problems, and a flex-rigid board that can improve the transmission characteristics of a high-frequency signal when the wiring of the flexible board is drawn out to the outermost layer of the rigid board. Another object of the present invention is to provide an optical transmission / reception module and an optical transmission / reception apparatus including the flex-rigid board.

In order to solve the above-described problems, a flex-rigid board according to the present invention includes a flexible board, a rigid board that is stacked on a part of the flexible board, and a signal wiring layer that is the outermost layer of the rigid board. A second microstrip line provided in an outermost signal wiring layer of the flexible substrate, the second microstrip line of the flexible substrate formed through the flexible substrate and the rigid substrate, A signal wiring via for connecting the first microstrip line of the rigid substrate, a plurality of first ground conductor layers provided on the rigid substrate corresponding to the first microstrip line, and a first of the flexible substrate The signal is provided corresponding to the microstrip line and the second microstrip line. A second grounding conductor layer having an opening through which the line via passes, and a first grounding conductor layer and a second grounding conductor formed at a predetermined position with respect to the signal wiring via through the flexible substrate and the rigid substrate; obtain Bei and via ground wiring for connecting the layer, the.
Then, a plurality of first grounding conductor layer to the vicinity of an opening through which a via signal lines, are formed to be extended in the direction of the flexible substrate corresponding to the first microstrip line in the rigid substrate, signal A virtual substrate connecting a wiring via and a ground wiring via, and a flexible substrate including a first region of a rigid substrate including a wiring region of a first microstrip line and a wiring region of a second microstrip line When the first substrate is divided into the second region of the rigid substrate, the first ground conductor layer is disposed in the first region, and the first region is not formed in the second region. And a ground wiring via is disposed in the first region where the first ground conductor layer is formed, and a signal wiring via is disposed in the second region where the ground layer opening is formed. Become There.

  In the flex-rigid board according to the present invention, a high-frequency signal is transmitted by a microstrip line provided in the outermost signal wiring layer of the flexible board and the rigid board, and a signal wiring via connecting the microstrip line. . At this time, a feedback current flows through each ground conductor layer and each ground wiring via corresponding to the microstrip line of the rigid substrate and the flexible substrate in a direction opposite to the signal current.

Here, in the vicinity of the signal wiring via of the ground conductor layer corresponding to the microstrip line of the rigid substrate, a region opposite to the wiring direction of the microstrip line of the rigid substrate from the predetermined region around the signal wiring via In FIG. 2, the ground conductor portion is not formed, and no feedback current flows in a region where the ground conductor portion is not formed.

  In addition, a parasitic capacitance corresponding to the ground conductor formed in a region other than the opening is generated between the signal wiring via and the ground conductor layer corresponding to the microstrip line of the rigid substrate.

An optical transmission / reception module according to the present invention includes an optical transmission module that converts an electrical signal into an optical signal and outputs the optical signal to a flex-rigid board, an optical reception module that converts the optical signal into an electrical signal, and an optical transmission / reception circuit. It is the optical transmission / reception module provided with . The flex-rigid board includes a flexible board and an optical transmission / reception circuit . The flex-rigid board is provided on a rigid board laminated on a part of the flexible board and a signal wiring layer on the outermost layer of the rigid board, and is connected to the optical transmission / reception circuit. A first microstrip line, a second microstrip line provided on the outermost signal wiring layer of the flexible substrate and connecting the first microstrip line and the optical transmission module or optical reception module, and a flexible substrate And the second microstrip line of the flexible substrate, the signal wiring via connecting the first microstrip line of the rigid substrate, and the first microstrip line corresponding to the rigid substrate. A plurality of first grounding conductor layers provided on the flexible substrate, A second grounding conductor layer provided corresponding to the microstrip line and the second microstrip line and having an opening through which the signal wiring via passes, and the flexible substrate and the rigid at a predetermined position with respect to the signal wiring via A ground wiring via formed through the substrate and connecting the first ground conductor layer and the second ground conductor layer ;
The plurality of first ground conductor layers are formed to extend in the direction of the flexible substrate in the rigid substrate in correspondence with the first microstrip line up to the vicinity of the opening through which the signal wiring via passes. A virtual substrate connecting a wiring via and a ground wiring via, and a flexible substrate including a first region of a rigid substrate including a wiring region of a first microstrip line and a wiring region of a second microstrip line When the first substrate is divided into the second region of the rigid substrate, the first ground conductor layer is disposed in the first region, and the first region is not formed in the second region. And a ground wiring via is disposed in the first region where the first ground conductor layer is formed, and a signal wiring via is disposed in the second region where the ground layer opening is formed. Become There.

  In the flex-rigid board of the optical transceiver module according to the present invention, when data is transmitted and received at high speed, the microstrip line provided in the outermost signal wiring layer of the flexible board and the rigid board, and the microstrip line High-frequency signals are transmitted through signal wiring vias that connect the two. At this time, a feedback current flows through each ground conductor layer and each ground wiring via corresponding to the microstrip line of the rigid substrate and the flexible substrate in a direction opposite to the signal current.

Here, in the vicinity of the signal wiring via of the ground conductor layer corresponding to the microstrip line of the rigid substrate, a region opposite to the wiring direction of the microstrip line of the rigid substrate from the predetermined region around the signal wiring via In FIG. 2, the ground conductor portion is not formed, and no feedback current flows in a region where the ground conductor portion is not formed.

  In addition, a parasitic capacitance corresponding to the ground conductor formed in a region other than the opening is generated between the signal wiring via and the ground conductor layer corresponding to the microstrip line of the rigid substrate.

An optical transmission / reception apparatus according to the present invention includes an optical transmission module that converts an electrical signal into an optical signal and outputs the optical signal to a flex-rigid board, an optical reception module that converts the optical signal into an electrical signal, and an optical transmission / reception circuit. It is the optical transmission / reception apparatus provided with . The flex-rigid board includes a flexible board and an optical transmission / reception circuit . The flex-rigid board is provided on a rigid board laminated on a part of the flexible board and a signal wiring layer on the outermost layer of the rigid board, and is connected to the optical transmission / reception circuit. A first microstrip line, a second microstrip line provided on the outermost signal wiring layer of the flexible substrate and connecting the first microstrip line and the optical transmission module or optical reception module, and a flexible substrate And the second microstrip line of the flexible substrate, the signal wiring via connecting the first microstrip line of the rigid substrate, and the first microstrip line corresponding to the rigid substrate. A plurality of first grounding conductor layers provided on the flexible substrate, A second ground conductor layer provided corresponding to the microstrip line and the second microstrip line and having an opening through which the signal wiring via passes, and a flexible substrate and a rigid substrate at predetermined positions with respect to the signal wiring via And a ground wiring via that connects the first ground conductor layer and the second ground conductor layer.
Then, a plurality of first grounding conductor layer to the vicinity of an opening through which a via signal lines, are formed to be extended in the direction of the flexible substrate corresponding to the first microstrip line in the rigid substrate, signal A virtual substrate connecting a wiring via and a ground wiring via, and a flexible substrate including a first region of a rigid substrate including a wiring region of a first microstrip line and a wiring region of a second microstrip line When the first substrate is divided into the second region of the rigid substrate, the first ground conductor layer is disposed in the first region, and the first region is not formed in the second region. And a ground wiring via is disposed in the first region where the first ground conductor layer is formed, and a signal wiring via is disposed in the second region where the ground layer opening is formed. Become There.

  In the flex-rigid board of the optical transceiver according to the present invention, when data is transmitted / received at a high speed, the microstrip line provided in the outermost signal wiring layer of the flexible board and the rigid board, and the microstrip line High-frequency signals are transmitted through signal wiring vias that connect the two. At this time, a feedback current flows through each ground conductor layer and each ground wiring via corresponding to the microstrip line of the rigid substrate and the flexible substrate in a direction opposite to the signal current.

Here, in the vicinity of the signal wiring via of the ground conductor layer corresponding to the microstrip line of the rigid substrate, a region opposite to the wiring direction of the microstrip line of the rigid substrate from the predetermined region around the signal wiring via In FIG. 2, the ground conductor portion is not formed, and no feedback current flows in a region where the ground conductor portion is not formed.

  In addition, a parasitic capacitance corresponding to the ground conductor formed in a region other than the opening is generated between the signal wiring via and the ground conductor layer corresponding to the microstrip line of the rigid substrate.

  According to the flex rigid board according to the present invention, when a signal current flows through the microstrip line and the signal wiring via, in the vicinity of the signal wiring via of the ground conductor layer corresponding to the microstrip line of the rigid board, Since the ground conductor is not formed in the region of the rigid substrate opposite to the wiring direction of the microstrip line, no feedback current flows. Thereby, the path of the feedback current flowing through the ground conductor layer corresponding to the microstrip line of the rigid substrate can be shortened.

  Further, according to the flex-rigid board according to the present invention, in the ground conductor layer corresponding to the microstrip line of the rigid board, the ground conductor part is not formed in the region opposite to the wiring direction of the microstrip line of the rigid board. It is. For this reason, the parasitic capacitance generated between the signal wiring via and the ground conductor layer corresponding to the microstrip line of the rigid substrate is reduced, and it can be suppressed that the characteristic impedance value of the signal wiring via is reduced. From the above, it is possible to improve the transmission characteristics of high-frequency signals.

  According to the optical transceiver module of the present invention, when a signal current flows through the microstrip line and the signal wiring via of the flex-rigid board, the signal wiring via of the ground conductor layer corresponding to the microstrip line of the rigid board is formed. In the vicinity, the ground conductor is not formed in the region opposite to the wiring direction of the microstrip line on the rigid substrate, so that no feedback current flows. Thereby, the path of the feedback current flowing through the ground conductor layer corresponding to the microstrip line of the rigid substrate can be shortened.

  Further, according to the flex-rigid board of the optical transceiver module according to the present invention, in the ground conductor layer corresponding to the microstrip line of the rigid board, the region opposite to the wiring direction of the microstrip line of the rigid board is the ground conductor. The part is not formed. For this reason, the parasitic capacitance generated between the signal wiring via and the ground conductor layer corresponding to the microstrip line of the rigid substrate is reduced, and it can be suppressed that the characteristic impedance value of the signal wiring via is reduced. As described above, high-frequency signal transmission characteristics can be improved, and high-speed data transmission / reception can be performed stably.

  According to the optical transceiver of the present invention, when a signal current flows through the microstrip line and the signal wiring via of the flex-rigid board, the signal wiring via of the ground conductor layer corresponding to the microstrip line of the rigid board is provided. In the vicinity, the ground conductor is not formed in the region opposite to the wiring direction of the microstrip line on the rigid substrate, so that no feedback current flows. Thereby, the path of the feedback current flowing through the ground conductor layer corresponding to the microstrip line of the rigid substrate can be shortened.

  Further, according to the flex-rigid board of the optical transceiver according to the present invention, in the ground conductor layer corresponding to the microstrip line of the rigid board, the region opposite to the wiring direction of the microstrip line of the rigid board is the ground conductor. The part is not formed. For this reason, the parasitic capacitance generated between the signal wiring via and the ground conductor layer corresponding to the microstrip line of the rigid substrate is reduced, and it can be suppressed that the characteristic impedance value of the signal wiring via is reduced. As described above, high-frequency signal transmission characteristics can be improved, and high-speed data transmission / reception can be performed stably.

  Embodiments of a flex-rigid board, 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 flex-rigid board will be described.

<Configuration Example of Flex-Rigid Substrate of First Embodiment>
FIG. 1 to FIG. 6 are explanatory diagrams showing the configuration of the flex-rigid substrate 1 according to the first embodiment. FIG. 1 is a plan view showing an outline of the flex-rigid substrate 1 and is shown by broken lines in a state where a part of the structure is seen through for explanation. FIG. 2 is a schematic view showing the AA cross section of FIG. FIG. 3 is a plan view showing a first wiring layer 10 to be described later, and a ground layer opening 35 of the second wiring layer 5 to be described later is indicated by a broken line for the sake of explanation. FIG. 4 is a plan view showing a second wiring layer 5, a fifth wiring layer 8, and a sixth wiring layer 9, which will be described later. FIG. 5 is a plan view showing a third wiring layer 6 to be described later, and a ground layer opening 36 of a fourth wiring layer 7 to be described later is indicated by a broken line for the sake of explanation. FIG. 6 is a plan view showing a fourth wiring layer to be described later, and the boundary between the flexible substrate portion 3 and the rigid substrate portion 4 is indicated by a broken line for the sake of explanation.

  As shown in FIG. 1 and FIG. 2, the flex-rigid board 1 includes a flexible board portion 3 composed only of a flexible board, and a rigid board portion 4 in which a rigid board is laminated on top and bottom of a part of the flexible board. . As shown in FIG. 2, the flexible substrate portion 3 is formed by stacking a third wiring layer 6, a third insulating layer 12, and a fourth wiring layer 7 on the top and bottom. The rigid substrate portion 4 is formed by alternately stacking first to sixth wiring layers and first to fifth insulating layers alternately above and below.

  As shown in FIGS. 3 and 5, the first wiring layer 10 and the third wiring layer 6 are wired with a pair of signal lines 15 as microstrip lines as signal wiring layers. As shown in FIGS. 4 and 6, the second wiring layer 5, the fourth wiring layer 7, the fifth wiring layer 8 and the sixth wiring layer 9 are formed with a ground layer 16. The ground layer 16 is an example of a ground conductor layer and a ground conductor portion.

  Further, as shown in FIGS. 1 to 6, there are a pair of signal vias 17 for connecting each signal line 15 provided in the first wiring layer 10 and each signal line 15 provided in the third wiring layer 6. These are arranged on the rigid board portion 4 at a predetermined interval. Furthermore, a pair of ground vias 18 connecting the ground layers 16 of the second wiring layer 5, the fourth wiring layer 7, the fifth wiring layer 8, and the sixth wiring layer 9 are provided in the rigid substrate portion 4. Each ground via 18 is arranged at a position sandwiching a pair of signal vias 17. The interval between the ground via 18 and the signal via 17 is formed, for example, equal to the interval between the signal vias 17 or wider than the interval between the signal vias 17. The signal vias 17 and the ground vias 18 are formed as through vias that are formed through the rigid substrate portion 4. The signal via 17 is an example of a signal wiring via, and the ground via 18 is an example of a ground wiring via.

  Also, as shown in FIG. 4, in each ground layer 16 formed in the second wiring layer 5, the fifth wiring layer 8, and the sixth wiring layer 9, for example, A ground layer opening 35 in which the ground layer 16 is not formed is provided. First, the ground layer 16 is not formed in a region which is divided by a line connecting the signal via 17 and the ground via 18 and is opposite to the wiring direction of the signal line 15 of the first wiring layer 10. Further, the signal via 17 is divided by a line connecting the ground via 18, and in a region on the wiring direction side of the signal line 15 of the first wiring layer 10, a predetermined size is formed around the pair of signal vias 17. The ground layer 16 is not formed in the semi-oval region. In the flex-rigid substrate 1 of the first embodiment shown in FIG. 4, the ground layer 16 is not formed up to the ends of the second wiring layer 5, the fifth wiring layer 8, and the sixth wiring layer 9. A ground layer opening 35 is provided.

  In the flex-rigid substrate 1 of the first embodiment, the ground layer opening 35 in the second wiring layer 5, the fifth wiring layer 8, and the sixth wiring layer 9 has the above-described configuration. The via 18 is located at the end of the ground layer 16 with respect to the ground layer opening 35.

  Further, as shown in FIG. 6, in the ground layer 16 formed in the fourth wiring layer 7, for example, the ground layer 16 is not formed in an oval region having a predetermined size around the pair of signal vias 17. A ground layer opening 36 to be formed is provided. The ground layer opening 35 and the ground layer opening 36 are examples of openings.

  Each ground layer 16 formed in the second wiring layer 5, the fifth wiring layer 8 and the sixth wiring layer 9 is divided by a line connecting the signal via 17 and the ground via 18, and the first wiring layer 10. In the region opposite to the wiring direction of the signal line 15, the ground layer 16 is not formed. Therefore, the parasitic capacitance generated between the signal via 17 and the ground layer 16 of the second wiring layer, the fifth wiring layer 8 and the sixth wiring layer 9 is smaller than that of the conventional flex-rigid substrate 50 shown in FIG. Get smaller.

  Further, in the flex-rigid substrate 1, for example, the distance between the pair of signal vias 17 is 1.4 mm, the distance between the pair of signal lines 15 in the first wiring layer 10 is 0.49 mm, and the pair of signal lines in the third wiring layer 6 The intervals of 15 are each formed at 0.8 mm. Therefore, the distance between the pair of signal vias 17 is wider than the distance between the pair of signal lines 15 in the first wiring layer 10 and the third wiring layer 6, so that the pair of signal lines 15 are shown in FIGS. 3 and 5. As shown in the figure, in the first wiring layer 10 and the third wiring layer 6, spread in an eight-character shape at locations corresponding to the ground layer openings 35 formed in the second wiring layer 5 and the fourth wiring layer 7, respectively. Formed as follows.

  In the flex-rigid board 1 of the first embodiment shown in FIGS. 1 to 6, a differential signal is transmitted by two signal lines 15. However, a single end mode signal may be transmitted through one signal line 15, and ground vias 18 may be arranged at predetermined intervals on both sides of the signal via 17 that performs interlayer connection of the signal line 15.

  Further, in each ground layer 16 formed in the second wiring layer 5, the fifth wiring layer 8 and the sixth wiring layer 9 of the flex-rigid substrate 1 of the first embodiment, as shown in FIG. As described above, the ground layer opening 35 is provided in which the ground layer 16 is not formed. In the ground layer opening 35, the ground layer 16 is not formed in a region which is divided by a line connecting the signal via 17 and the ground via 18 and is opposite to the wiring direction of the signal line 15 of the first wiring layer 10. Further, in a region which is divided by a line connecting the signal via 17 and the ground via 18 and is on the wiring direction side of the signal line 15 of the first wiring layer 10, a predetermined size is provided around the pair of signal vias 17. In this semi-oval region, the ground layer 16 is not formed.

  However, in each ground layer 16 formed in the second wiring layer 5, the fifth wiring layer 8, and the sixth wiring layer 9, the wiring of the signal line 15 of the first wiring layer 10 from a predetermined region around the signal via 17. A ground layer opening 35 in which the ground layer 16 is not formed may be provided in a region opposite to the direction.

<Configuration Example of Flex-Rigid Substrate of Second Embodiment>
Next, the configuration of the flex-rigid board 2 according to the second embodiment will be described. As will be described later, the flex-rigid board 2 of the second embodiment is a flex-rigid board 1 of the first embodiment in which each signal line 15 connected to the signal via 17 is tapered. It is.

  FIG. 8 to FIG. 13 are explanatory diagrams showing the configuration of the flex-rigid board 2 according to the second embodiment. FIG. 8 is a plan view showing an outline of the flex-rigid substrate 2 and is shown by broken lines in a state where a part of the configuration is seen through for explanation. FIG. 9 is a schematic view showing a CC cross section of FIG. FIG. 10 is a plan view showing a first wiring layer 10 to be described later, and a ground layer opening 35 of the second wiring layer 5 to be described later is indicated by a broken line for the sake of explanation. FIG. 11 is a plan view showing a second wiring layer 5, a fifth wiring layer 8, and a sixth wiring layer 9, which will be described later. FIG. 12 is a plan view showing a third wiring layer 6 to be described later, and a ground layer opening 36 of a fourth wiring layer 7 to be described later is indicated by a broken line for the sake of explanation. FIG. 13 is a plan view showing a fourth wiring layer to be described later, and the boundary between the flexible substrate portion 3 and the rigid substrate portion 4 is indicated by a broken line for the sake of explanation.

  As shown in FIGS. 8 and 9, the flex-rigid board 2 of the second embodiment is similar to the flexible board 1 of the first embodiment. And a rigid substrate portion 4 in which a rigid substrate is laminated on a part of the flexible substrate. Further, as shown in FIG. 16, the flexible substrate portion 3 and the rigid substrate portion 4 are formed by alternately stacking first to sixth wiring layers and first to fifth insulating layers alternately above and below.

  Furthermore, the flex-rigid board 2 of the second embodiment has the following configuration, like the flexible board 1 of the first embodiment.

  As shown in FIGS. 10 and 12, the first wiring layer 10 and the third wiring layer 6 are wired with a pair of signal lines 15 which are microstrip lines as signal wiring layers. As shown in FIGS. 11 and 13, the second wiring layer 5, the fourth wiring layer 7, the fifth wiring layer 8 and the sixth wiring layer 9 are formed with a ground layer 16. The ground layer 16 is an example of a ground conductor layer and a ground conductor portion.

  Further, as shown in FIGS. 8 to 13, there are a pair of signal vias 17 that connect each signal line 15 provided in the first wiring layer 10 and each signal line 15 provided in the third wiring layer 6. These are arranged on the rigid board portion 4 at a predetermined interval. Furthermore, a pair of ground vias 18 connecting the ground layers 16 of the second wiring layer 5, the fourth wiring layer 7, the fifth wiring layer 8, and the sixth wiring layer 9 are provided in the rigid substrate portion 4. Each ground via 18 is arranged at a position sandwiching a pair of signal vias 17. The interval between the ground via 18 and the signal via 17 is formed, for example, equal to the interval between the signal vias 17 or wider than the interval between the signal vias 17. The signal vias 17 and the ground vias 18 are formed as through vias that are formed through the rigid substrate portion 4. The signal via 17 is an example of a signal wiring via, and the ground via 18 is an example of a ground wiring via.

  In addition, as shown in FIG. 11, in each ground layer 16 formed in the second wiring layer 5, the fifth wiring layer 8, and the sixth wiring layer 9, for example, A ground layer opening 35 in which the ground layer 16 is not formed is provided. First, the ground layer 16 is not formed in a region which is divided by a line connecting the signal via 17 and the ground via 18 and is opposite to the wiring direction of the signal line 15 of the first wiring layer 10. Further, the signal via 17 is divided by a line connecting the ground via 18, and in a region on the wiring direction side of the signal line 15 of the first wiring layer 10, a predetermined size is formed around the pair of signal vias 17. The ground layer 16 is not formed in the semi-oval region. In addition, in the flex-rigid substrate 2 of the second embodiment shown in FIG. 11, the ground layer 16 is not formed up to the ends of the second wiring layer 5, the fifth wiring layer 8, and the sixth wiring layer 9. A ground layer opening 35 is provided.

  In the flex-rigid substrate 2 of the second embodiment, the ground layer opening 35 has the above-described configuration in the second wiring layer 5, the fifth wiring layer 8, and the sixth wiring layer 9. The via 18 is located at the end of the ground layer 16 with respect to the ground layer opening 35.

  Further, as shown in FIG. 13, in the ground layer 16 formed in the fourth wiring layer 7, for example, the ground layer 16 is not formed in an oval region having a predetermined size around the pair of signal vias 17. A ground layer opening 36 to be formed is provided. The ground layer opening 35 and the ground layer opening 36 are examples of openings.

  Each ground layer 16 formed in the second wiring layer 5, the fifth wiring layer 8 and the sixth wiring layer 9 is divided by a line connecting the signal via 17 and the ground via 18, and the first wiring layer 10. In the region opposite to the wiring direction of the signal line 15, the ground layer 16 is not formed. Therefore, the parasitic capacitance generated between the signal via 17 and the ground layer 16 of the second wiring layer, the fifth wiring layer 8 and the sixth wiring layer 9 is smaller than that of the conventional flex-rigid substrate 50 shown in FIG. Get smaller.

  Further, in the flex-rigid board 2, for example, the distance between the pair of signal vias 17 is 1.4 mm, the distance between the pair of signal lines 15 in the first wiring layer 10 is 0.49 mm, and the pair of signal lines in the third wiring layer 6 The intervals of 15 are each formed at 0.8 mm. Therefore, the distance between the pair of signal vias 17 is wider than the distance between the pair of signal lines 15 in the first wiring layer 10 and the third wiring layer 6, so that the pair of signal lines 15 are shown in FIGS. 10 and 12. As shown in the figure, in the first wiring layer 10 and the third wiring layer 6, spread in an eight-character shape at locations corresponding to the ground layer openings 35 formed in the second wiring layer 5 and the fourth wiring layer 7, respectively. Formed as follows.

  In the flex-rigid board 2, for example, the line width of the signal line 15 of the first wiring layer 10 is 0.19 mm, the line width of the signal line 15 of the third wiring layer 6 is 0.1 mm, the signal via 17 and the ground. The vias 18 are each formed with a diameter of 0.55 mm. Unlike the flexible substrate 1 of the first embodiment, the flex-rigid substrate 2 of the second embodiment is provided on the first wiring layer 10 and the third wiring layer 6 as shown in FIGS. 10 and 12. Each signal line 15 corresponds to the predetermined line width of each signal line 15 and the diameter of the signal via 17 at a position corresponding to the ground layer opening 35 formed in the second wiring layer 5 and the fourth wiring layer 7. Thus, it is formed in a tapered shape so as to expand toward the signal via 17.

  In the flex-rigid board 2 according to the second embodiment shown in FIGS. 8 to 13, a differential signal is transmitted by two signal lines 15. However, a single end mode signal may be transmitted through one signal line 15, and ground vias 18 may be arranged at predetermined intervals on both sides of the signal via 17 that performs interlayer connection of the signal line 15.

  Further, in each ground layer 16 formed in the second wiring layer 5, the fifth wiring layer 8 and the sixth wiring layer 9 of the flex-rigid substrate 2 of the second embodiment, as shown in FIG. As described above, the ground layer opening 35 is provided in which the ground layer 16 is not formed. In the ground layer opening 35, the ground layer 16 is not formed in a region which is divided by a line connecting the signal via 17 and the ground via 18 and is opposite to the wiring direction of the signal line 15 of the first wiring layer 10. Further, in a region which is divided by a line connecting the signal via 17 and the ground via 18 and is on the wiring direction side of the signal line 15 of the first wiring layer 10, a predetermined size is provided around the pair of signal vias 17. In this semi-oval region, the ground layer 16 is not formed.

  However, in each ground layer 16 formed in the second wiring layer 5, the fifth wiring layer 8, and the sixth wiring layer 9, the wiring of the signal line 15 of the first wiring layer 10 from a predetermined region around the signal via 17. A ground layer opening 35 in which the ground layer 16 is not formed may be provided in a region opposite to the direction.

<Operation Example of Flex-Rigid Board of First and Second Embodiments>
Next, operation examples of the flex-rigid substrate 1 of the first embodiment and the flex-rigid substrate 2 of the second embodiment will be described. In the flex-rigid substrates 1 and 2, a differential signal is transmitted through a pair of signal lines 15 provided in the first wiring layer 10 and the third wiring layer 6. When a signal is transmitted, a pair of signal lines 15 of the first wiring layer 10 and the third wiring layer 6 and a pair of signal lines 15 of the first wiring layer 10 and the third wiring layer 6 are connected. A signal current flows through the signal via 17.

  FIG. 7 is a plan view showing the flow of signal current and feedback current when a high-frequency signal is transmitted through the signal line 15 of the flex-rigid board 1 of the first embodiment. FIG. It is a top view which shows the flow of the signal current at the time of transmitting a high frequency signal in the signal track | line 15 of the flex-rigid board | substrate 2 of embodiment, and a feedback current. 7 and 14 show the signal line 15 provided in the first wiring layer 10 and the ground layer 16 provided in the second wiring layer 5. When a high-frequency signal is transmitted to the signal line 15 on the flex-rigid substrates 1 and 2, a current flows through the signal line 15 as indicated by an arrow E in FIG. 7 and an arrow P in FIG. At this time, a feedback current flows through the ground layer 16 as indicated by an arrow F in FIG. 7 and an arrow Q in FIG.

  Here, the high-frequency feedback current has a property of flowing through the end portion of the ground layer 16. However, the second wiring layer 5 of the flex-rigid substrates 1 and 2 is divided by a line connecting the signal via 17 and the ground via 18 and is an area on the opposite side of the wiring direction of the signal line 15 of the first wiring layer 10. , The ground layer 16 is not formed. For this reason, the feedback current does not take a greatly detoured path as in the conventional flex-rigid substrate 50 indicated by the arrow N in FIG. 26, but takes a short path as indicated by the arrow F in FIG. 7 and the arrow P in FIG. Flowing. Therefore, the flex-rigid substrates 1 and 2 can reduce the transmission loss of the feedback current as compared with the conventional flex-rigid substrate 50, and can improve the transmission characteristics of the high-frequency signal of the signal line 15. Become.

  In addition, the flex-rigid substrates 1 and 2 are divided by lines connecting the signal vias 17 and the ground vias 18, and the ground layer 16 is not formed in a region opposite to the wiring direction of the signal line 15 of the first wiring layer 10. Formation. Therefore, the parasitic capacitance generated between the signal via 17 and the ground layer 16 of the second wiring layer 5 is smaller than that of the conventional flex-rigid substrate 50 shown in FIG. Therefore, it can be suppressed that the value of the characteristic impedance of the signal via 17 becomes small due to the influence of the ground layer 16 of the second wiring layer 5. This makes it possible to improve the transmission characteristics of high-frequency signals on the signal line 15.

  The flex-rigid board 1 according to the first embodiment, the flex-rigid board 2 according to the second embodiment, and the conventional flex-rigid board 50 are configured such that the ground layer 16 is removed from the second wiring layer 5 in a predetermined shape. A layer opening 35 or a ground layer opening 36 is provided. Therefore, in the portion corresponding to the ground layer opening 35 or the ground layer opening 36 of the second wiring layer 5, each signal line 15 of the first wiring layer 10 is weakly coupled to the ground layer 16 and the parasitic capacitance is reduced. The characteristic impedance value becomes large.

  However, in the flex-rigid board 2 of the second embodiment, as shown in FIG. 10, each signal line 15 provided in the first wiring layer 10 has a ground layer opening formed in the second wiring layer 5. A portion corresponding to the portion 35 is formed to be tapered toward the signal via 17. For this reason, the coupling between the signal line 15 and the end of the second wiring layer 5 shown in FIG. Therefore, it is possible to prevent an increase in the value of the characteristic impedance due to the reduction in parasitic capacitance, and to improve the high-frequency signal transmission characteristics of the signal line 15.

  Similarly, in the flex-rigid board 1 of the first embodiment, the flex-rigid board 2 of the second embodiment, and the conventional flex-rigid board 50, the ground layer 16 is removed in a predetermined shape in the fourth wiring layer 7. The ground layer opening 36 is provided. Therefore, in the part corresponding to the ground layer opening 36 of the second wiring layer 5, each signal line 15 of the third wiring layer 6 is weakly coupled to the ground layer 16, and the parasitic capacitance is reduced and the characteristic impedance value is increased. turn into.

  However, in the flex-rigid substrate 2 of the second embodiment, as shown in FIG. 12, each signal line 15 provided in the third wiring layer 6 has a ground layer opening formed in the fourth wiring layer 7. Since the portion corresponding to the portion 36 is formed so as to be tapered toward the signal via 17, the coupling between the signal line 15 and the end portion of the fourth wiring layer 7 shown in FIG. 12D is strengthened. Therefore, it is possible to prevent an increase in the value of the characteristic impedance due to the reduction in parasitic capacitance, and to improve the high-frequency signal transmission characteristics of the signal line 15.

  The flex-rigid substrate 1 of the first embodiment, the flex-rigid substrate 2 of the second embodiment, and the conventional flex-rigid substrate 50 are as shown in B of FIG. 2, O of FIG. 9, and K of FIG. The stub portion that does not contribute to the transmission of the signal current is formed in the signal via 17. This stub portion reduces the characteristic impedance of the transmission line and causes the transmission characteristic to deteriorate. However, in the flex-rigid substrate 1 of the first embodiment and the flex-rigid substrate 2 of the second embodiment, as shown in FIGS. 3 and 10, in the fifth wiring layer 8 and the sixth wiring layer 9, The ground layer 16 is not formed in a region that is divided by a line connecting the signal via 17 and the ground via 18 and is opposite to the wiring direction of the signal line 15 of the first wiring layer 10.

  For this reason, the flex-rigid substrate 1 of the first embodiment and the flex-rigid substrate 2 of the second embodiment are connected to the signal via 17 and the ground layers 16 of the fifth wiring layer 8 and the sixth wiring layer 9. Since the parasitic capacitance generated between them is smaller than that of the conventional flex-rigid substrate 50, the decrease in the characteristic impedance of the transmission line due to the stub portion shown in B of FIG. 2 and O of FIG. 9 can be reduced. The deterioration of the transmission line can be suppressed, and the transmission characteristics of the high frequency signal of the signal line 15 can be improved.

  FIG. 15 is a diagram showing the measurement results of the reflection loss of the signal current on the signal line 15 at each frequency of the flex-rigid board 1 of the first embodiment and the flex-rigid board 2 of the second embodiment. . G shows the measurement result of the flex-rigid substrate 1 of the first embodiment, and H shows the measurement result of the flex-rigid substrate 2 of the second embodiment.

  The dimensions of each part in each measurement result are as follows. In the flex-rigid substrate 1 of the first embodiment and the flex-rigid substrate 2 of the second embodiment, the line width of the signal line 15 of the first wiring layer 10 is 0.19 mm, and the third wiring layer 6 The line width of the signal line 15 is 0.1 mm. Further, in the flex-rigid board 1 of the first embodiment and the flex-rigid board 2 of the second embodiment, the distance between the signal lines 15 of the first wiring layer 10 indicated by L5 in FIG. 3 and L13 in FIG. Is 0.3 mm, the distance between the signal lines 15 of the third wiring layer 6 indicated by L8 in FIG. 5 and L16 in FIG. 12 is 0.7 mm, and the signal indicated by L3 in FIG. 3 and L11 in FIG. The distance between the centers of the vias 17 is 1.4 mm, and the distance between the centers of the signal vias 17 and the ground vias 18 indicated by L4 in FIG. 3 and L12 in FIG. 10 is 1.4 mm. Furthermore, in the flex-rigid substrate 1 of the first embodiment and the flex-rigid substrate 2 of the second embodiment, the diameter of each signal via 17 and each ground via 18 is 0.55 mm.

  Further, in the flex-rigid substrate 1 of the first embodiment and the flex-rigid substrate 2 of the second embodiment, the length shown by L1 in FIG. 3 and L9 in FIG. 10 is 2.5 mm, and FIG. The length shown in L2 and L10 in FIG. 10 is 5.5 mm, the length shown in L6 in FIG. 5 and L14 in FIG. 12 is 2.5 mm, and the length shown in L7 in FIG. 5 and L15 in FIG. Is 11.0 mm.

  Further, in the flex-rigid substrate 1 of the first embodiment and the flex-rigid substrate 2 of the second embodiment, the value of the relative permittivity of the rigid substrate is 4.6, and the value of tan δ is 0.01. Yes, the metal thickness of each wiring layer is 0.03 mm. The relative dielectric constant of the flexible substrate is 3.1, the value of tan δ is 0.005, and the metal thickness of each wiring layer is 0.02 mm.

  In order to perform stable transmission of a high-speed signal, it is necessary that the reflection loss of the transmission path is −15 dB or less at the transmission data rate frequency. As shown in FIG. 15, the flex-rigid board 1 of the first embodiment can perform stable signal transmission up to about 13 GHz.

  Further, the flex-rigid board 2 of the second embodiment in which an improvement is made such that the connection portion of each signal line 15 to the signal via 17 is tapered with respect to the flex-rigid board 1 of the first embodiment. Then, it becomes possible to stably transmit a high-speed signal of 20 GHz or more. As described above, the flex-rigid board 1 of the first embodiment can perform stable transmission of high-speed signals. In the flex-rigid board 2 of the second embodiment, the flex of the first embodiment is used. As compared with the rigid substrate 1, it can be confirmed that a higher-speed signal can be stably transmitted.

  Next, as an embodiment of the optical transceiver module and the optical transceiver apparatus according to the present invention, an optical transceiver module and a network card using the flex-rigid board 1 of the present embodiment will be described.

<Configuration example of optical transceiver module and network card of this embodiment>
FIGS. 16 to 19 are explanatory diagrams showing configurations of the optical transceiver module 19 and the network card 20 of the present embodiment. FIG. 16 is a plan view schematically showing a first example of the optical transceiver module 19 and network card 20 of the present embodiment, and FIG. 17 is a first diagram of the optical transceiver module 19 and network card 20 of the present embodiment. It is sectional drawing which shows the outline of an example. 18 is a plan view showing an outline of the second example of the optical transceiver module 19 and the network card 20, and FIG. 19 is a cross-sectional view showing an outline of the second example of the optical transceiver module 19 and the network card 20. 17 and 19, 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. 16 to 19, the network card 20 includes an optical transceiver module 19 having an optical cable connector 33, an FPC (Flexible Printed Circuit) 21 for optical transceiver board connection, a host board 23 having an optical transceiver circuit unit B22, and A bezel 24 attached to the end of the host board 23 is provided. 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 FPC 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 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. In addition, the flex rigid board constituted by the FPC 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 has the flex rigid of the first embodiment shown in FIGS. The substrate 1 or the flex-rigid substrate 2 of the second embodiment shown in FIGS. 8 to 14 is applied.

  In the first example of the optical transceiver module 19 and the network card 20 shown in FIGS. 16 and 17, the optical transceiver board connecting FPC 21 is soldered to the host board 23 as indicated by I. Thereby, compared with the case where FPC21 for optical transmission / reception board connection and the host board 23 are connected by a connector, a number of parts can be reduced and cost can be reduced.

  Further, the optical transceiver module 19 and the network card 20 of the second example shown in FIGS. 18 and 19 are connected to the optical transceiver board connecting FPC 21 by the FPC connector 34 provided on the host board 23. This makes it possible to easily attach the optical transceiver board FPC 21 to the host board 23 as compared with the optical transceiver module 19 and the network card 20 of the first example shown in FIGS. Become.

  In the optical transceiver module 19 and the network card 20 of the present embodiment described with reference to FIGS. 16 to 19, 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 described with reference to FIGS. 16 to 19, 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. 16 to 19 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.

  Further, as described above, when data is transmitted / received to / from an external information communication device through an optical cable, the FPC 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 configured. A high-frequency electrical signal is transmitted on the signal line of the flex-rigid board. 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 transmission / reception module 19 and the network card 20 of the present embodiment, the flex rigid board composed of the FPC 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 is shown in FIG. The flex-rigid board 1 of the first embodiment shown in FIG. 7 or the flex-rigid board 2 of the second embodiment shown in FIGS. 8 to 14 is applied. This enables high-quality signal transmission and stable data transmission / reception even when high-frequency signals are transmitted to each signal line of the flex-rigid board by performing high-speed data transmission / reception. It becomes.

  The present invention is applied to a flex-rigid board in which a flexible board and a rigid board are connected, and an optical transmission / reception module and an optical transmission / reception apparatus including the flex-rigid board.

It is a top view of the flex-rigid board of a 1st embodiment. It is sectional drawing of the flex-rigid board | substrate of 1st Embodiment. It is a top view of the flex-rigid board of a 1st embodiment. It is a top view of the flex-rigid board of a 1st embodiment. It is a top view of the flex-rigid board of a 1st embodiment. It is a top view of the flex-rigid board of a 1st embodiment. It is a top view of the flex-rigid board of a 1st embodiment. It is a top view of the flex-rigid board of a 2nd embodiment. It is sectional drawing of the flex-rigid board | substrate of 2nd Embodiment. It is a top view of the flex-rigid board of a 2nd embodiment. It is a top view of the flex-rigid board of a 2nd embodiment. It is a top view of the flex-rigid board of a 2nd embodiment. It is a top view of the flex-rigid board of a 2nd embodiment. It is a top view of the flex-rigid board of a 2nd embodiment. It is a measurement result of the reflection loss in the flex-rigid board of the 1st and 2nd embodiment. 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 top view of the conventional flex-rigid board | substrate. It is sectional drawing of the conventional flex-rigid board | substrate. It is a top view of the conventional flex-rigid board | substrate. It is a top view of the conventional flex-rigid board | substrate. It is a top view of the conventional flex-rigid board | substrate. It is a top view of the conventional flex-rigid board | substrate. It is a top view of the conventional flex-rigid board | substrate.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Flex rigid board, 2 ... Flex rigid board, 3 ... Flexible board part, 4 ... Rigid board part, 15 ... Signal track, 16 ... Ground layer, 17 ... Signal via, 18 ... ground via, 19 ... optical transceiver module, 21 ... FPC for optical transceiver board connection, 23 ... host board, 27 ... TOSA, 28 ... ROSA, 29. .... FPC for ROSA connection, 30 ... FPC for TOSA connection, 32 ... Optical transceiver board, 35 ... Ground layer opening, 36 ... Ground layer opening

Claims (7)

A flexible substrate;
A rigid substrate laminated vertically on a part of the flexible substrate;
A first microstrip line provided in an outermost signal wiring layer of the rigid substrate;
A second microstrip line provided in an outermost signal wiring layer of the flexible substrate;
A signal wiring via that is formed through the flexible substrate and the rigid substrate, and connects the second microstrip line of the flexible substrate and the first microstrip line of the rigid substrate;
A plurality of first grounding conductor layers provided on the rigid substrate in correspondence with the first microstrip line;
A second grounding conductor layer provided on the flexible substrate corresponding to the first microstrip line and the second microstrip line, and having an opening through which the signal wiring via passes;
A ground wiring via that is formed through the flexible substrate and the rigid substrate at a predetermined position with respect to the signal wiring via, and connects the first ground conductor layer and the second ground conductor layer; Bei to give a,
The plurality of first ground conductor layers are formed to extend in the direction of the flexible substrate corresponding to the first microstrip line in the rigid substrate up to the vicinity of the opening through which the signal wiring via passes. And
A virtual line connecting the signal wiring via and the ground wiring via, the first region of the rigid substrate including the wiring region of the first microstrip line, and the second microstrip line When the flexible substrate including the wiring region is divided into the second region of the rigid substrate that overlaps,
The first ground conductor layer is disposed in the first region, and a ground layer opening in which the first ground conductor layer is not formed is provided in the second region.
The ground wiring via is disposed in the first region where the first ground conductor layer is formed, and the signal wiring via is disposed in the second region where the ground layer opening is formed. To be
Flex rigid board. The flex-rigid board according to claim 1, wherein an opening through which the signal wiring via of the second ground conductor layer has an oval shape. The first microstrip line and the second microstrip line are located at locations corresponding to the openings of the second ground conductor layer corresponding to the first microstrip line and the second microstrip line. , Formed so as to be tapered toward the signal wiring via
Flex-rigid substrate of 請 Motomeko 1, wherein the. A differential signal is transmitted by the pair of first microstrip lines and the pair of second microstrip lines formed at a predetermined interval on the flexible substrate and the rigid substrate,
A pair of the signals arranged at a predetermined interval connecting the pair of second microstrip lines formed on the flexible substrate and the pair of first microstrip lines formed on the rigid substrate. The flex rigid according to claim 1, further comprising: a wiring via; and a pair of ground wiring vias arranged with respect to each of the signal wiring vias at an interval equal to or larger than an arrangement interval of the pair of signal wiring vias. substrate. A pair of the second microstrip lines and a pair of the first microstrip lines are respectively formed on the flexible substrate and the rigid substrate at an interval narrower than an arrangement interval of the pair of signal wiring vias,
From the terminal portion of the plurality of first ground conductor layers in the direction of the flexible substrate, on the flexible substrate side,
According to an interval between the pair of second microstrip lines, an interval between the pair of first microstrip lines, and an arrangement interval between the pair of signal wiring vias, the gaps spread toward the signal wiring vias. The flex-rigid board according to claim 4 formed. An optical transmission module that includes an optical transmission module that converts an electrical signal into an optical signal and outputs the optical signal on a flex-rigid board, an optical reception module that converts an optical signal into an electrical signal, and an optical transmission / reception circuit,
The flex-rigid board is
A flexible substrate;
A rigid substrate that includes the optical transceiver circuit and is laminated on a part of the flexible substrate; and
A first microstrip line provided in an outermost signal wiring layer of the rigid substrate and connected to the optical transceiver circuit;
A second microstrip line that is provided in an outermost signal wiring layer of the flexible substrate and connects the first microstrip line and the optical transmission module or the optical reception module;
A signal wiring via that is formed through the flexible substrate and the rigid substrate, and connects the second microstrip line of the flexible substrate and the first microstrip line of the rigid substrate;
A plurality of first grounding conductor layers provided on the rigid substrate in correspondence with the first microstrip line;
A second grounding conductor layer provided on the flexible substrate corresponding to the first microstrip line and the second microstrip line, and having an opening through which the signal wiring via passes;
A ground wiring via that is formed through the flexible substrate and the rigid substrate at a predetermined position with respect to the signal wiring via, and connects the first ground conductor layer and the second ground conductor layer; With
The plurality of first ground conductor layers are formed to extend in the direction of the flexible substrate corresponding to the first microstrip line in the rigid substrate up to the vicinity of the opening through which the signal wiring via passes. And
A virtual line connecting the signal wiring via and the ground wiring via, the first region of the rigid substrate including the wiring region of the first microstrip line, and the second microstrip line When the flexible substrate including the wiring region is divided into the second region of the rigid substrate that overlaps,
The first ground conductor layer is disposed in the first region, and a ground layer opening in which the first ground conductor layer is not formed is provided in the second region.
The ground wiring via is disposed in the first region where the first ground conductor layer is formed, and the signal wiring via is disposed in the second region where the ground layer opening is formed. To be
Optical transceiver module. An optical transmission / reception apparatus including an optical transmission module that converts an electrical signal into an optical signal and outputs the optical signal on a flex-rigid board, an optical reception module that converts the optical signal into an electrical signal, and an optical transmission / reception circuit
The flex-rigid board is
A flexible substrate;
A rigid substrate that includes the optical transceiver circuit and is laminated on a part of the flexible substrate; and
A first microstrip line provided in an outermost signal wiring layer of the rigid substrate and connected to the optical transceiver circuit;
A second microstrip line that is provided in an outermost signal wiring layer of the flexible substrate and connects the first microstrip line and the optical transmission module or the optical reception module;
A signal wiring via that is formed through the flexible substrate and the rigid substrate, and connects the second microstrip line of the flexible substrate and the first microstrip line of the rigid substrate;
A plurality of first grounding conductor layers provided on the rigid substrate in correspondence with the first microstrip line;
A second grounding conductor layer provided on the flexible substrate corresponding to the first microstrip line and the second microstrip line, and having an opening through which the signal wiring via passes;
A ground wiring via that is formed through the flexible substrate and the rigid substrate at a predetermined position with respect to the signal wiring via, and connects the first ground conductor layer and the second ground conductor layer;
Equipped with a,
The plurality of first ground conductor layers are formed to extend in the direction of the flexible substrate corresponding to the first microstrip line in the rigid substrate up to the vicinity of the opening through which the signal wiring via passes. And
A virtual line connecting the signal wiring via and the ground wiring via, the first region of the rigid substrate including the wiring region of the first microstrip line, and the second microstrip line When the flexible substrate including the wiring region is divided into the second region of the rigid substrate that overlaps,
The first ground conductor layer is disposed in the first region, and a ground layer opening in which the first ground conductor layer is not formed is provided in the second region.
The ground wiring via is disposed in the first region where the first ground conductor layer is formed, and the signal wiring via is disposed in the second region where the ground layer opening is formed. To be
Optical transceiver.

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