JP2013026601A - Printed wiring board, printed wiring board module, optical communication module, optical communication device and arithmetic processing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a printed wiring board suppressing unexpected reduction of impedance if position deviation between a layer having a signal conductor and a GND plane layer occurs.SOLUTION: The printed wiring board includes: a signal conductor 11 including a heating terminal 11c electrically connected to a rigid substrate 2, a wiring portion 11b having a narrower width than the heating terminal 11c, and a connection portion 11a connected to the heating terminal 11c and to the wiring portion 11b and having a gradually varying width; and a GND plane layer, which is a layer other than a layer having the formed wiring portion 11b, having a formed GND conductor 15 and including a hollow 17 produced by hollowing the GND conductor 15 at a portion corresponding to the connection portion 11a and the heating terminal 11c. A distance from a boundary portion between the connection portion 11a and the wiring portion 11b to the GND conductor 15 in the horizontal direction is equal to or greater than the thickness of a dielectric between the GND plane layer and the signal conductor 11.

Description

  The present invention relates to a printed wiring board, a printed wiring board module, an optical communication module, an optical communication device, and an arithmetic processing device.

  When a plurality of printed wiring boards (hereinafter referred to as “substrates”) are installed in a small housing such as a mobile phone and an optical transceiver module and a signal is transmitted across the plurality of substrates, means for directly connecting the substrates to each other is provided. Many are used. In particular, a flexible printed circuit board (hereinafter referred to as “FPC board”) is a mobile phone that connects two rigid boards whose relative orientation changes, and signals are transmitted at high speed between the board and the module. Often used in communications applications.

In the former mobile phone or the like, a connector is used as a connection mechanism between the signal wiring of two substrates, the power source, and the GND.
In the latter optical transmission / reception module and the like, it is not uncommon for the signal speed to increase every year to reach several Gbps, and the frequency component included in the signal waveform exceeds 10 GHz. It is expected that the speed will continue to improve.

  In order to cope with such high speed, in the latter optical transmission / reception module, etc., the signal wiring, power supply and GND are connected by directly contacting pads (terminals) provided on the substrate or by soldering. Thus, a technique for obtaining electrical continuity is used.

  In the connection portion between the substrates, the dimensions of the signal conductor and the positional relationship with respect to the GND conductor are discontinuous, and as a result, the impedance of the signal wiring may be discontinuous. Such a discontinuity in impedance causes a deterioration of the signal waveform. For this reason, various methods are employed to match the impedance of the signal transmission path as much as possible at the connection portion. The FPC board has a smaller conductor interlayer thickness and a thinner wiring width than the rigid board. As a result, the dimensional difference between the wiring conductor and the connecting portion conductor becomes larger than that of the rigid board, and the problem is serious.

  For this reason, in the system in which the signal conductor and the GND conductor of the two boards are directly soldered and connected, by optimizing the signal wiring terminal, the GND terminal and the peripheral conductor layout of both boards, A method for mitigating impedance mismatching has been proposed (for example, Patent Document 1).

JP 2007-123744 A

However, in the conventional method, the position where the taper of the signal conductor starts and the boundary between the GND conductors overlap each other, and when the position of the layer where the signal conductor is located and the GND plane layer are shifted when each substrate is laminated, However, there is a problem that the impedance is unexpectedly lowered due to overlapping with the tapered portion of the signal conductor.
The present invention has been made to solve the above-described problems. Even when the position where the signal conductor layer and the GND plane layer are misaligned, the GND conductor becomes a tapered portion of the signal conductor. An object of the present invention is to provide a printed wiring board which does not overlap and thereby suppresses an unexpected decrease in impedance.

  The printed wiring board according to the present invention is gradually connected to a terminal part electrically connected to another printed wiring board, a signal wiring part narrower than the terminal part, and the terminal part and the signal wiring part. The signal conductor composed of the changing connection portion is different from the layer where the signal wiring portion is formed, and the GND conductor is formed, and the GND conductor corresponding to the connection portion and the terminal portion is cut. A GND plane layer having a cutout portion, and a horizontal distance from a boundary portion between the connection portion and the signal wiring portion to the GND conductor is equal to or greater than a thickness of the dielectric between the GND plane layer and the signal conductor. It is characterized by being.

  According to the present invention, the horizontal distance from the boundary portion between the connection portion and the signal wiring portion to the GND conductor is more than a certain distance, so the positions of the layer with the signal conductor and the GND plane layer are shifted. Even in this case, it is possible to provide a printed wiring board in which the GND conductor does not overlap the tapered portion of the signal conductor, thereby suppressing an unexpected decrease in impedance.

3 is a plan view of the FPC board according to Embodiment 1. FIG. It is a figure which shows the structure of the surface and back surface of the FPC board shown in FIG. It is sectional drawing in the III-III 'cut surface of FIG.1 and FIG.4. It is a top view of the rigid board | substrate shown in FIG. FIG. 2 is an enlarged view of the vicinity of a boundary portion between a connection portion and a wiring portion in the FPC board shown in FIG. 1. 3 is a plan view of the FPC board according to Embodiment 1. FIG. 6 is a plan view of an FPC board according to Embodiment 2. FIG. It is a figure which shows the structure of the surface and back surface of the FPC board shown in FIG. It is sectional drawing in the IX-IX 'cut surface of FIG.7 and FIG.10. It is a top view of the rigid board | substrate shown in FIG.

Embodiment 1 FIG.
FIG. 1 is a plan view of an FPC board 1 according to the first embodiment. FIG. 2 is a view showing the FPC board 1 shown in FIG. 1 divided into a front side configuration and a back side configuration. 3 is a cross-sectional view taken along the line III-III ′ of FIGS. FIG. 4 is a plan view of the rigid substrate 2 shown in FIG.
In the first embodiment, a case of differential signal pair wiring will be described as an example.

  1-4, 1 is an FPC board (printed wiring board, first printed wiring board, second printed wiring board), 2 is a rigid board (other printed wiring boards, second printed wiring board, first 3 is a solder for electrically connecting the rigid board 2 and the FPC board 1. In order to make the figure easy to understand, the thickness of the solder 3 is displayed thicker than the actual thickness. Although described below using solder, the electrical connection between the rigid substrate 2 and the FPC substrate 1 is not limited to solder, and for example, a conductive adhesive or the like may be used. Or you may make it contact, without using solder, a conductive adhesive, etc.

11 is a signal conductor on the surface of the FPC board, 11a is a tapered connection part, 11b is a wiring part (signal wiring part) having a predetermined impedance, 11c is a heating terminal (terminal part), and 12 is a signal on the back side of the FPC board. Conductor, 13 is a signal terminal (connection terminal, first connection terminal, second connection terminal) on the back surface of the FPC board, 14 is a GND conductor which is a heating terminal on the surface of the FPC board, and 15 is partially cut out. The GND conductor on the back surface of the FPC board formed on the GND plane layer, 16 is a GND terminal (connection terminal, first connection terminal, second connection terminal) on the back surface of the FPC board, and 17 is a GND conductor on the back surface of the FPC board. A hollow 18 is a via that connects the conductors on the front and back surfaces of the FPC board.
Note that “GND” in a GND conductor, a GND plane, a GND terminal, and the like described here includes both a GND as an electric circuit and a power supply (the same applies hereinafter).

  21 is a signal conductor on the surface of the rigid substrate, 23 is a signal terminal (second connection terminal, first connection terminal) on the surface of the rigid substrate, 24 is a GND conductor on the surface of the rigid substrate, and 25 is a back surface of the rigid substrate. A GND conductor, 26 is a GND terminal (second connection terminal, first connection terminal) on the surface of the rigid board, 28 is a through-hole connecting the conductors on the front and back surfaces of the rigid board, and 29 is a hollow area.

The FPC board 1 is a double-sided board with conductors on both sides.
In general, there are protective films on the front and back surfaces of the FPC board, but they are omitted in this figure. In the protective film, the signal terminal 13 and the GND terminal 16 are opened on the back surface, and solder is applied to the opening.

  Further, when the FPC board 1 and the rigid board 2 are soldered, heat is applied from the surface of the FPC board 1 to the solder 3 between the signal terminal 13 and the signal terminal 23 via the via 18. A protective film in approximately the same region is also opened.

  The FPC board 1 has a microstrip structure in which one side of the FPC board 1 is a GND plane layer provided with the GND conductor 15 and the other side is a layer provided with the signal wiring (signal conductor 11). There is an effect that the impedance of 11b can be stabilized.

  A GND wiring 30 described later may be further provided on the left and right sides of the signal wiring (wiring portion 11b), and the GND wiring 30 and the GND conductor 15 on the opposite surface may be connected by a plurality of Vias 18 at short intervals. By doing so, there is an effect that the impedance of the wiring portion 11b in the FPC board 1 can be further stabilized.

  Further, the signal conductor 11 may be provided on the surface of the FPC board 1 facing the rigid board 2.

FIG. 2A is a diagram showing the configuration of the front surface of the FPC board 1, and FIG. 2B is a diagram showing the configuration of the back surface of the FPC board 1.
As shown in FIG. 2A, the connecting portion 11a is disposed between the relatively narrow wiring portion 11b and the wide heating terminal 11c, and has the same width as the wiring portion 11b. A taper whose width changes linearly from the end portion to the end portion on the heating terminal 11c side having the same width as the heating terminal 11c is provided.
The change in the width of the connecting portion 11a is not limited to a linear taper, but may be other shapes that gradually change.

  In general, a double-sided FPC board has a thin dielectric between the conductors on the front and back sides. Therefore, in order to achieve a desired wiring impedance, it is necessary to reduce the width of the signal wiring (wiring portion 11b). It becomes about half of the wiring width or less. On the other hand, for ease of soldering and prevention of disconnection due to distortion at the time of connection, the size of the terminal to be soldered (signal terminal 13) is substantially the same as the size of the rigid board side terminal (signal terminal 23).

  For this reason, if the microstrip structure is used, the width of the signal terminal 13 is much larger than the width of the wiring portion 11b, leading to a reduction in impedance.

  By providing the connecting portion 11a having the above-described configuration, it is possible to make the impedance at the tapered connecting portion 11a and the heating terminal 11c close to the impedance of the wiring portion 11b while avoiding a sudden change in the impedance of the signal conductor 11. effective.

FIG. 5 is an enlarged view of the vicinity of the boundary between the connection portion 11 a and the wiring portion 11 b of the FPC board 1.
In the FPC board 1 according to the first embodiment, the horizontal distance from the boundary portion between the connection portion 11a and the wiring portion 11b to the GND conductor 15 is between the GND conductor 15 (GND plane layer) and the signal conductor 11. More than the thickness of the dielectric.

  More specifically, as shown in FIG. 5, the boundary between the GND conductor 15 and the cutout 17 includes a vertical portion that overlaps the wiring portion 11b perpendicularly and an inclined portion that continues to the vertical portion, and the connection portion 11a. Parallel to the wiring portion 11b in the horizontal direction from the boundary portion with the wiring portion 11b (point indicated by X in FIG. 5) to the contact point (point indicated by Y in FIG. 5) between the vertical portion and the inclined portion. Both the distance in the direction and the distance in the direction perpendicular to the wiring portion 11 b are equal to or greater than the thickness of the dielectric between the GND conductor 15 (GND plane layer) and the signal conductor 11.

That is, assuming that the direction parallel to the wiring portion 11b in the plane parallel to the GND conductor 15 is Δx and the direction perpendicular to the wiring portion 11b is Δy, Δx and Δy satisfy the following equations (1) and (2).
Δx ≧ t (1)
Δy ≧ t (2)
However, t is the thickness of the dielectric between the conductor on the front surface of the FPC board 1 (signal conductor 11) and the conductor on the back surface (GND conductor 15).
The inclined portion at the boundary between the GND conductor 15 and the cutout 17 is a straight line having a larger taper than the taper of the connecting portion 11a. Therefore, the distance in the horizontal direction between the connecting portion 11a and the GND conductor 15 increases from the end of the connecting portion 11a toward the end of the heating terminal 11c from the end of the wiring portion 11b.
The shape of the inclined portion and the shape of the tapered portion of the connecting portion 11a are not limited to a straight line, as long as the distance increases from the end of the connecting portion 11a toward the end of the heating terminal 11c toward the end of the wiring portion 11b. It may be a simple shape. For example, an arc shape may be used.

With the above structure, when the FPC board 1 is manufactured, the positions of the front surface conductor (signal conductor 11) and the back surface conductor (GND conductor 15) are shifted, and the GND conductor 15 is located under the connection portion 11a thicker than the wiring portion 11b. It is possible to prevent overlapping and locally becoming low impedance.
When a substrate is manufactured by stacking, the stacking position is shifted due to various causes such as thermal expansion (lamination misalignment). The maximum value of the stacking deviation is approximately t in both the direction parallel to the wiring portion 11b and the direction perpendicular to the wiring portion 11b. Therefore, by setting the values of Δx and Δy to be t or more, there is an effect that the influence of the stacking deviation can be appropriately mitigated and an unexpected decrease in impedance can be suppressed.

  In this embodiment, the FPC board 1 has a tapered shape, but the present invention can be similarly applied even when the rigid board 2 has a tapered shape.

  In this embodiment, the description has been made using the double-sided substrate. However, it may be a multilayer substrate of three or more layers having a plurality of GND plane layers.

  Further, in the present embodiment, the example in which the signal conductor 11 is the differential signal pair wiring has been described, but a single-ended wiring may be used. Further, the signal conductor 11 may include both a differential signal pair wiring and a single-ended wiring. In the above case, there may be a plurality of differential signal pair wirings, single-ended wirings, or both.

It is good also as a structure (structure with a guard GND) provided with the GND wiring 30 arrange | positioned on the right and left of the signal conductor 11, and further having Via18 which connects the said GND wiring 30 and the GND conductor 15 in a short space | interval. By doing so, the impedance of the wiring part 11b can be stabilized.
FIG. 6 is a diagram showing a case in which one single-end wiring and one differential signal pair wiring are provided, and the GND wiring 30 is further provided.
When a plurality of signal conductors 11 are provided, a plurality of GND wirings 30 connected to the GND conductors 15 via the vias 18 are provided on at least part of the signal conductors 11 and outside the signal conductors 11 at both ends. Also good. The GND wiring 30 between the plurality of signal conductors 11 is preferably provided only between the signal conductors 11 having different signals.
The cutout 17 may be provided for each of some of the signal conductors 11. For example, the signal conductor 11 for a high-speed signal may be provided with the cutout 17, and the signal conductor 11 for the low-speed signal may not be provided with the cutout 17.

  As described above, the FPC board 1 according to the first embodiment includes the heating terminal 11c that is electrically connected to the rigid board 2, the wiring portion 11b that is narrower than the heating terminal 11c, and the heating terminal 11c and the wiring portion 11b. The signal conductor 11 formed of the connecting portion 11a that is connected and gradually changes in width is a layer different from the layer in which the wiring portion 11b is formed, the GND conductor 15 is formed, the connecting portion 11a and the heating A GND plane layer having a cutout 17 in which a portion of the GND conductor 15 corresponding to the terminal 11c is cut out, and a horizontal distance from the boundary portion between the connection portion 11a and the wiring portion 11b to the GND conductor 15 is GND. The thickness of the dielectric between the plane layer and the signal conductor 11 is set to be equal to or greater than that. For this reason, when the horizontal distance from the boundary portion between the connecting portion 11a and the wiring portion 11b to the GND conductor 15 is more than a certain distance, the position of the layer with the signal conductor 11 and the GND plane layer is shifted. Even so, it is possible to provide the FPC board 1 in which the GND conductor 15 does not overlap the tapered portion (connecting portion 11a) of the signal conductor 11, thereby suppressing an unexpected decrease in impedance.

  Further, according to the first embodiment, the boundary between the GND conductor 15 and the cutout 17 includes the vertical portion that overlaps the wiring portion 11b perpendicularly and the inclined portion that continues to the vertical portion, and the connection portion 11a and the wiring portion 11b. The distance in the direction parallel to the wiring portion 11b and the distance in the direction perpendicular to the wiring portion 11b from the boundary portion to the contact point between the vertical portion and the inclined portion are both between the GND plane layer and the signal conductor 11. Since the distance in the horizontal direction from the boundary portion between the connecting portion 11a and the wiring portion 11b to the GND conductor 15 is more than a certain distance, the layer with the signal conductor 11 is formed. The GND conductor 15 does not overlap the tapered portion (connecting portion 11a) of the signal conductor 11 even when the positions of the GND plane layer and the GND plane layer are shifted, thereby suppressing an unexpected decrease in impedance. It is possible to provide a C substrate 1.

  Further, according to the first embodiment, the signal conductor 11 is composed of a single single-end signal conductor, and therefore can be applied to a general printed wiring board using a single-end signal conductor.

  Further, according to the first embodiment, the signal conductor 11 is composed of two differential signal conductors, and therefore can be applied to a printed wiring board using the differential signal conductors.

  Further, according to the first embodiment, a plurality of signal conductors 11 are provided, arranged at least partially between the plurality of signal conductors 11 and outside the signal conductors 11 at both ends, and electrically connected to the GND conductor 15. Since the plurality of GND wirings 30 are provided and the cutouts 17 are provided for each part of the plurality of signal conductors 11, the impedance is stabilized even when the plurality of signal conductors 11 are provided. Can be made.

Embodiment 2. FIG.
A second embodiment of the present invention will be described with reference to FIGS. In these drawings, the same or corresponding components as those described with reference to FIGS. 1-6 are assigned the same element numbers, and redundant descriptions are omitted.

  FIG. 7 is a plan view of the FPC board 1 according to Embodiment 2 of the present invention. FIG. 8 is a diagram showing the FPC board 1 shown in FIG. 7 divided into a front side configuration and a back side configuration. FIG. 9 is a cross-sectional view taken along the line IX-IX ′ of FIGS. 7 and 10. FIG. 10 is a plan view of the rigid substrate 2.

  7-10, 33 is a signal terminal (connection terminal, first connection terminal, second connection terminal) on the back surface of the FPC board, and 36 is a GND terminal (connection terminal, first connection terminal) on the back surface of the FPC board. Terminal, second connection terminal).

  As shown in FIG. 7-10, the signal terminal 33 of the second embodiment is smaller than the signal terminal 23 on the surface of the rigid substrate 2. The GND terminal 36 is smaller than the GND terminal 26 on the surface of the rigid board 2.

More specifically, as shown in FIG. 7, the signal terminal 33 and the GND terminal 36 are t (on both sides of the signal conductor 11 of the FPC board 1) compared to the external dimensions of the signal terminal 23 and the GND terminal 26. The thickness of the dielectric with respect to the GND conductor 15) is smaller.
Note that only two sides in the vertical direction in FIG.

  Conventionally, when the soldering position, particularly the soldering position in the direction in which the terminals are arranged, is shifted, the signal terminal of the FPC board and the GND terminal of the rigid board, and the signal terminal of the GND terminal of the FPC board and the rigid board There is a problem that the impedance at the terminal portion, which originally tends to be low impedance, is further reduced.

  With the above structure, even when the FPC board 1 is soldered to the rigid board 2, the signal terminals 33 and the GND terminals 36 of the FPC board 1 are connected to the signal terminals 23 and the GND terminals 26 of the rigid board 2. Don't stick out.

Thereby, the parasitic capacitance is generated by the distance between the signal terminal 33 of the FPC board 1 and the GND terminal 26 of the rigid board 2 and the distance between the GND terminal 36 of the FPC board 1 and the signal terminal 23 of the rigid board 2 being closer, There is an effect that local low impedance can be prevented.
As described above, the maximum value of the stacking deviation when the substrate is manufactured by stacking is approximately t in both the direction parallel to the wiring portion 11b and the direction perpendicular to the wiring portion 11b. Therefore, the external dimensions of the signal terminal 33 and the GND terminal 36 in the direction in which the signal terminal 33 and the GND terminal 36 are arranged (that is, the direction perpendicular to the wiring portion 11b) are the same as the external dimensions of the signal terminal 23 and the GND terminal 26. By making it smaller than the dimension by t or more, there is an effect that the influence of the stacking deviation can be appropriately mitigated and an unexpected decrease in impedance can be suppressed.

  Although the present embodiment has been described using an example in which the terminals (the signal terminal 33 and the GND terminal 36) of the FPC board 1 are made smaller than the terminals (the signal terminal 23 and the GND terminal 26) of the rigid board 2, the opposite is true. Even if it exists (that is, even if the signal terminal 23 and the GND terminal 26 are made smaller than the signal terminal 33 and the GND terminal 36), the same effect can be obtained.

  In the second embodiment, the description has been made using the double-sided substrate, but the present invention can also be applied to a multilayer substrate of three or more layers having a plurality of GND plane layers.

  Furthermore, in the second embodiment, the example in which the signal conductor 11 is a differential signal pair wiring has been described, but a single-ended wiring may be used. Further, the signal conductor 11 may include both a differential signal pair wiring and a single-ended wiring. In the above case, there may be a plurality of differential signal pair wirings, single-ended wirings, or both.

  Further, the FPC board 1, the rigid board 2 or both may have the configuration described in the first embodiment.

  From the above, the printed wiring board module according to Embodiment 2 is connected to the heating terminal 11c, the wiring portion 11b having a width smaller than that of the heating terminal 11c, and the connection portion in which the width is gradually changed by connecting to the heating terminal 11c and the wiring portion 11b. A signal conductor 11 made of 11a, a GND conductor 15 formed on a layer different from the layer on which the signal conductor 11 is formed, and a first connection terminal (signal) electrically connected to the signal conductor 11 or the GND conductor 15 The first printed wiring board (FPC board 1 and rigid board 2) provided with the terminals 33 and 23 and the GND terminals 36 and 26) and the first connection terminal are electrically connected (by solder or the like). And a second printed wiring board (rigid board 2, FPC board 1) provided with second connection terminals (signal terminals 23 and 33, GND terminals 26 and 36), and the first connection terminal in the first connection terminal. of The absolute value of the difference between the external dimension in the direction in which the connection terminals are arranged and the external dimension in the direction at the second connection terminal is equal to or greater than the thickness of the dielectric between the signal conductor 11 and the GND conductor 15. Configured. Therefore, even when the soldering position, particularly the soldering position in the direction in which the first connection terminals are arranged, is shifted, the signal terminal 33 of the FPC board 1, the GND terminal 26 of the rigid board 2, and the FPC board 1. Therefore, it is possible to provide a printed wiring module in which the GND terminal 36 and the signal terminal 23 of the rigid board 2 do not approach each other, thereby suppressing an unexpected decrease in impedance.

  Further, according to the second embodiment, since the FPC board 1 and / or the rigid board 2 are further configured as described in the first embodiment, the GND conductor 15 is connected to the tapered portion (connection portion) of the signal conductor 11. 11a), it is possible to suppress an unexpected drop in impedance.

The printed wiring board (FPC board 1) or the printed wiring board module (FPC board 1 and rigid board 2) described in the first embodiment or the second embodiment can be applied to an optical communication module.
The optical communication module can be applied to an optical communication device.

  The printed wiring board or the printed wiring board module described in the first embodiment or the second embodiment can be applied to an arithmetic processing device.

  In the present invention, within the scope of the invention, any combination of the embodiments, or any modification of any component in each embodiment, or omission of any component in each embodiment is possible. .

  1 FPC board (printed wiring board, first printed wiring board, second printed wiring board), 2 rigid board (other printed wiring boards, second printed wiring board, first printed wiring board), 3 solder , 11 signal conductor, 11a connection portion, 11b wiring portion (signal wiring portion), 11c heating terminal (terminal portion), 12 signal conductor, 13, 33 signal terminal (connection terminal, first connection terminal, second connection terminal) ), 14 GND conductor, 15 GND conductor, 16, 36 GND terminal (connection terminal, first connection terminal, second connection terminal), 17 hollow, 18 Via, 21 signal conductor, 23 signal terminal (second connection) Terminal, first connection terminal), 24 GND conductor, 25 GND conductor, 26 GND terminal (second connection terminal, first connection terminal), 28 through hole, 29 cutout region, 30 ND wiring.

Claims (14)

It consists of a terminal part electrically connected to another printed wiring board, a signal wiring part having a narrower width than the terminal part, and a connecting part connected to the terminal part and the signal wiring part and gradually changing in width. A signal conductor;
The GND is a layer different from the layer in which the signal wiring portion is formed, the GND conductor is formed, and the GND has a hollow portion in which the GND conductor corresponding to the connection portion and the terminal portion is hollowed out. With a plain layer,
A horizontal distance from a boundary portion between the connection portion and the signal wiring portion to the GND conductor is equal to or greater than a thickness of a dielectric between the GND plane layer and the signal conductor. Wiring board. The boundary between the GND conductor and the hollowed portion includes a vertical portion that overlaps the signal wiring portion perpendicularly, and an inclined portion that continues to the vertical portion,
The distance in the direction parallel to the signal wiring part in the horizontal direction and the distance in the direction perpendicular to the signal wiring part from the boundary part between the connection part and the signal wiring part to the contact point between the vertical part and the inclined part are: The printed wiring board according to claim 1, wherein both are equal to or greater than a thickness of a dielectric between the GND plane layer and the signal conductor.   2. The printed wiring board according to claim 1, wherein the signal conductor is composed of a single single-ended signal conductor.   2. The printed wiring board according to claim 1, wherein the signal conductor is composed of two differential signal conductors. A plurality of the signal conductors are provided,
A plurality of GND wires disposed at least in part between the plurality of signal conductors and outside the signal conductors at both ends, and electrically connected to the GND conductor;
The printed wiring board according to claim 1, wherein the cut-out portion is provided for each part of the plurality of signal conductors.   The printed wiring board according to claim 1, wherein the printed wiring board has a rigid structure.   The printed wiring board according to claim 1, wherein the printed wiring board is a flexible structure. A signal conductor composed of a terminal portion, a signal wiring portion narrower than the terminal portion, and a connection portion connected to the terminal portion and the signal wiring portion and gradually changing in width; and a layer on which the signal conductor is formed; Is a first printed wiring board provided with a GND conductor formed in another layer and a first connection terminal electrically connected to the signal conductor or the GND conductor;
A second printed wiring board provided with a second connection terminal electrically connected to the first connection terminal;
The absolute value of the difference between the outer dimension of the first connecting terminal in the direction in which the first connecting terminals are arranged and the outer dimension of the second connecting terminal in the direction is the signal conductor and the GND conductor. A printed wiring board module having a thickness greater than or equal to the thickness of the dielectric between the printed wiring board modules.   9. The printed wiring board module according to claim 8, wherein the first printed wiring board further comprises the structure of the printed wiring board according to any one of claims 1 to 5.   An optical communication module comprising the printed wiring board according to any one of claims 1 to 5.   An optical communication module comprising the printed wiring board module according to claim 8.   An optical communication apparatus comprising the optical communication module according to claim 10.   An arithmetic processing apparatus comprising the printed wiring board according to claim 1.   An arithmetic processing apparatus comprising the printed wiring board module according to claim 8.

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