Differential transmission board set and assembly

Abstract

To improve transmission characteristics of a differential transmission board set.SOLUTION: A differential transmission board set 4 is formed by combining a mounting board 7, on which a compression connector 5 is mounted, with a contact board 6 configured to come into contact with the compression connector 5. In the contact board 6, a second conductor layer 6CL2 is a ground layer and has a penetrating hole 55. The penetrating hole 55 is formed such that a first signal pad 35 and a second signal pad 36 are both located inside an inner edge 55A of the penetrating hole 55. In the contact board 6, the penetrating hole 55 is formed to overlap an outer region 33Q of a first ground pad 33 and an outer region 34Q of a second ground pad 34.SELECTED DRAWING: Figure 10

Description

Technical Field

[0001] The present invention relates to a substrate set and an assembly for differential transmission.

Background Art

[0002] Patent Document 1 discloses a paddle card substrate 1002, which is a multilayer substrate in which a plurality of conductor layers 1000 and a plurality of insulator layers 1001 are alternately laminated, as shown in FIG. 36 of the present application. The plurality of conductor layers 1000 include a first conductor layer 1000A, a second conductor layer 1000B, a third conductor layer 1000C, and a fourth conductor layer 1000D. The plurality of insulator layers 1001 include a first insulator layer 1001A, a second insulator layer 1001B, and a third insulator layer 1001C. From the surface side to the inner layer side of the paddle card substrate 1002, the first conductor layer 1000A, the first insulator layer 1001A, the second conductor layer 1000B, the second insulator layer 1001B, the third conductor layer 1000C, the third insulator layer 1001C, and the fourth conductor layer 1000D are arranged in this order.

[0003] The first conductor layer 1000A is formed with two cable connection pads 1003 to which two signal line conductors of a differential signal transmission cable are soldered, and two ground pads 1004 arranged so as to sandwich the two cable connection pads 1003.

[0004] Through holes 1005B and 1005C overlapping the two cable connection pads 1003 in the lamination direction are respectively formed in the second conductor layer 1000B and the third conductor layer 1000C, thereby suppressing the capacitive coupling between the two cable connection pads 1003 and the second conductor layer 1000B, and thus preventing a decrease in the differential impedance at the two cable connection pads 1003.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

[0006] Incidentally, the inventors of the present invention have developed two differential transmission boards that are electrically connected to each other via a compression connector, each of which comprises a plurality of compression contacts including soldering parts and spring parts, and a housing that holds the plurality of compression contacts. The two differential transmission boards are combined to form a differential transmission board set.

[0007] The purpose of this disclosure is to provide a technology for improving the transmission characteristics of differential transmission substrate sets. [Means for solving the problem]

[0008] According to a first aspect of this disclosure, a differential transmission board set comprising two differential transmission boards electrically connected to each other via a compression connector, each having four compression contacts arranged in a row including a soldering portion and a spring portion, and a housing that holds the four compression contacts, wherein the two differential transmission boards include a mounting board on which the compression connector is mounted, and a contact board that contacts the compression connector, and both the mounting board and the contact board are plurality A multilayer substrate is formed by alternately stacking a conductor layer and a plurality of insulating layers, and in both the mounting substrate and the contact substrate, the plurality of conductor layers include a first conductor layer and a second conductor layer in the order described herein, starting from the compression connector side, and in both the mounting substrate and the contact substrate, the first conductor layer has four electrode pads corresponding to the four compression contacts, and the four electrode pads include a first signal pad, a second signal pad, a first ground pad, and a second ground pad, and the first ground pad, the first signal pad, and the front The second signal pad and the second ground pad are arranged in this order along the first direction, and in the mounting substrate, the soldering portions of the four compression contacts can be soldered to the first ground pad, the first signal pad, the second signal pad, and the second ground pad, respectively, and in the contact substrate, the spring portions of the four compression contacts can be in contact to the first ground pad, the first signal pad, the second signal pad, and the second ground pad, respectively, and in both the mounting substrate and the contact substrate, the second conductor layer is a ground layer and has through holes formed therein, and in both the mounting substrate and the contact substrate, the through holes are formed such that, when viewed from the stacking direction, the first signal pad and the second signal pad are both located inside the inner edge of the through holes, and in both the mounting substrate and the contact substrate, the first ground pad has an inner region closer to the first signal pad than the bisector that bisects the pad area of ​​the first ground pad in the first direction,A differential transmission substrate set is provided, comprising an outer region further from the first signal pad than the bisector, and in both the mounting substrate and the contact substrate, the second ground pad comprises an inner region closer to the second signal pad than the bisector that bisects the pad area of ​​the second ground pad in the first direction, and an outer region further from the second signal pad than the bisector, and in at least one of the mounting substrate and the contact substrate, the through-hole is formed such that, when viewed along the stacking direction, it overlaps the outer region of the first ground pad and the outer region of the second ground pad. In only one of the mounting substrate and the contact substrate, the through-hole may be formed such that, when viewed along the stacking direction, it overlaps with the outer region of the first ground pad and the outer region of the second ground pad. In both the mounting substrate and the contact substrate, the plurality of conductor layers further include a third conductor layer, and the first conductor layer, the second conductor layer, and the third conductor layer are stacked in this order from the compression connector side, and in both the mounting substrate and the contact substrate, the third conductor layer is a ground layer and may overlap the first signal pad and the second signal pad in the stacking direction. In both the mounting substrate and the contact substrate, the plurality of conductor layers further include a third conductor layer, a fourth conductor layer, and a fifth conductor layer, and the first conductor layer, the second conductor layer, the third conductor layer, the fourth conductor layer, and the fifth conductor layer are stacked in this order from the compression connector side, and in both the mounting substrate and the contact substrate, the third conductor layer and the fourth conductor layer are ground layers with through holes formed therein, and in both the mounting substrate and the contact substrate, the through holes in the third conductor layer and the fourth conductor layer are formed such that, when viewed from the stacking direction, the first signal pad and the second signal pad are both located inside the inner periphery of the through hole, and in both the mounting substrate and the contact substrate, the fifth conductor layer is a ground layer and may overlap the first signal pad and the second signal pad in the stacking direction. The system may also consist of two differential transmission boards that are electrically connected to each other via a compression connector, which has multiple compression contact groups, each consisting of four compression contacts arranged in a row. In at least one of the mounting substrate and the contact substrate, the plurality of conductor layers include, in order from the compression connector side, the first conductor layer, the second conductor layer, ... the (N-1)th conductor layer, and the Nth conductor layer (where N is a natural number of 4 or more), and the Nth conductor layer includes a first signal pad and a second signal pad that are electrically connected to the first signal pad and the second signal pad of the first conductor layer, respectively, and the (N-1)th conductor layer is a ground layer and may overlap with the first signal pad and the second signal pad of the Nth conductor layer in the stacking direction. An assembly is provided that includes the above-mentioned differential transmission board set and the compression connector. [Effects of the Invention]

[0009] According to this disclosure, the transmission characteristics of a differential transmission substrate set can be improved. [Brief explanation of the drawing]

[0010] [Figure 1] It is an exploded perspective view of an information processing apparatus. (First Embodiment) [Figure 2] It is an exploded perspective view of the information processing apparatus seen from another angle. (First Embodiment) [Figure 3] It is a cross-sectional view of a differential transmission assembly. (First Embodiment) [Figure 4] It is a partial bottom view of the first conductor layer of a contact substrate. (First Embodiment) [Figure 5] It is a partial bottom view of the second conductor layer of a contact substrate. (First Embodiment) [Figure 6] It is a partial bottom view of the third conductor layer of a contact substrate. (First Embodiment) [Figure 7] It is a partial bottom view of the fourth conductor layer of a contact substrate. (First Embodiment) [Figure 8] It is a partial bottom view of the fifth conductor layer of a contact substrate. (First Embodiment) [Figure 9] It is a partial bottom view of the sixth conductor layer of a contact substrate. (First Embodiment) [Figure 10] It is a projection view of a plurality of conductor layers of a contact substrate. (First Embodiment) [Figure 11] It is a partial plan view of the first conductor layer of a mounting substrate. (First Embodiment) [Figure 12] It is a partial plan view of the second conductor layer of a mounting substrate. (First Embodiment) [Figure 13] It is a partial plan view of the third conductor layer of a mounting substrate. (First Embodiment) [Figure 14] It is a partial plan view of the fourth conductor layer of a mounting substrate. (First Embodiment) [Figure 15] It is a partial plan view of the fifth conductor layer of a mounting substrate. (First Embodiment) [Figure 16] It is a partial plan view of the sixth conductor layer of a mounting substrate. (First Embodiment) [Figure 17] It is a projection view of a plurality of conductor layers of a mounting substrate. (First Embodiment) [Figure 18] It is a partial bottom view of the third and fourth conductor layers of a contact substrate. (First Variant) [Figure 19] Partial plan view of the third and fourth conductor layers of the mounting substrate. (First modification example) [Figure 20] Projection view of a plurality of conductor layers of the contact substrate. (Second embodiment) [Figure 21] Projection view of a plurality of conductor layers of the mounting substrate. (Second embodiment) [Figure 22] Projection view of a plurality of conductor layers of the contact substrate. (Third embodiment) [Figure 23] Projection view of a plurality of conductor layers of the mounting substrate. (Third embodiment) [Figure 24] Projection view of a plurality of conductor layers of the contact substrate. (Fourth embodiment) [Figure 25] Projection view of a plurality of conductor layers of the mounting substrate. (Fourth embodiment) [Figure 26] Projection view of a plurality of conductor layers of the contact substrate. (Fifth embodiment) [Figure 27] Projection view of a plurality of conductor layers of the mounting substrate. (Fifth embodiment) [Figure 28] Partial bottom view of the second to fourth conductor layers of the contact substrate. (Comparative example) [Figure 29] Partial plan view of the second to fourth conductor layers of the mounting substrate. (Comparative example) [Figure 30] Graph showing the analysis result of insertion loss [Figure 31] Graph showing the analysis result of return loss [Figure 32] Graph showing the analysis result of differential impedance by the TDR method <00​​​​​​​​​​​​​

[0011] (First Embodiment) The first embodiment will be described below with reference to Figures 1 to 17.

[0012] Figures 1 and 2 show exploded perspective views of the information processing device 1. As shown in Figures 1 and 2, the information processing device 1 includes a differential transmission assembly 2 and a support board 3.

[0013] The differential transmission assembly 2 includes a differential transmission board set 4 and a compression connector 5.

[0014] The differential transmission board set 4 includes a contact board 6 and a mounting board 7. The contact board 6 and the mounting board 7 are electrically connected to each other via a compression connector 5. Both the contact board 6 and the mounting board 7 are differential transmission boards. The contact board 6 and the mounting board 7 are parallel to each other while being electrically connected to each other via the compression connector 5.

[0015] The contact substrate 6 has two bolt fastening holes 6A. Similarly, the mounting substrate 7 has two bolt fastening holes 7A.

[0016] The support board 3 is typically part of a housing that accommodates the contact board 6, compression connector 5, and mounting board 7, and is made of, for example, aluminum or an aluminum alloy. The support board 3 includes a flat board body 8 and two nuts 9 protruding from the board body 8.

[0017] The information processing device 1 is assembled as follows: First, the compression connector 5 is mounted on the mounting board 7. Next, the mounting board 7 with the compression connector 5 mounted is attached to the support board 3. At this time, the two nuts 9 of the support board 3 pass through the two bolt fastening holes 7A of the mounting board 7.

[0018] Then, the contact board 6 is attached to the support board 3 so that it overlaps the compression connector 5. Specifically, two bolts 10 are fastened to two nuts 9 on the support board 3 via two bolt fastening holes 6A on the contact board 6. As a result, the contact board 6 is pressed against the compression connector 5 and makes contact with the compression connector 5, and as a result, the contact board 6 and the mounting board 7 are electrically connected to each other via the compression connector 5. In other words, the compression connector 5 is not mounted on the contact board 6, and the compression connector 5 and the contact board 6 only make contact with each other when the contact board 6 is pressed against the compression connector 5.

[0019] Continuing with reference to Figures 1 and 2, the compression connector 5 includes a plurality of compression contacts 11 and a housing 12 that holds the plurality of compression contacts 11. The plurality of compression contacts 11 constitute a plurality of contact rows 13. The plurality of contact rows 13 extend parallel to each other.

[0020] Here, we define the pitch direction, width direction, and vertical direction. The pitch direction, width direction, and vertical direction are mutually orthogonal directions. The pitch direction is the direction of each contact row 13. The width direction is the direction in which multiple contact rows 13 extending parallel to each other are arranged. The vertical direction is the direction in which the contact substrate 6 and the compression connector 5, and the compression connector 5 and the mounting substrate 7 face each other. Therefore, the thickness direction of the contact substrate 6 and the thickness direction of the mounting substrate 7 coincide with the vertical direction. The direction in which the contact substrate 6 is viewed from the compression connector 5 is referred to as upward, and the direction in which the mounting substrate 7 is viewed from the compression connector 5 is referred to as downward. The vertical direction is merely a direction defined for the sake of explanation and does not indicate the actual orientation of the information processing device 1 in use.

[0021] Figure 3 shows a cross-sectional view of the differential transmission assembly 2. As shown in Figure 3, each compression contact 11 is housed in the contact housing chamber 12A of the housing 12 by press-fitting. Each compression contact 11 includes a soldering portion 20, a spring portion 21, and a press-fit portion 22. The spring portion 21 has a contact portion 21A that is elastically displaceable in the vertical direction. The spring portion 21 is cantilevered by the press-fit portion 22, allowing the contact portion 21A to be elastically displaceable in the vertical direction.

[0022] The contact substrate 6 is a multilayer substrate in which multiple conductor layers 6CL and multiple insulating layers 6SL are alternately stacked. The multiple conductor layers 6CL include, in order from the compression connector 5 side upwards, a first conductor layer 6CL1, a second conductor layer 6CL2, a third conductor layer 6CL3, a fourth conductor layer 6CL4, a fifth conductor layer 6CL5, and a sixth conductor layer 6CL6. The multiple insulating layers 6SL include, in order from the compression connector 5 side upwards, a first insulating layer 6SL1, a second insulating layer 6SL2, a third insulating layer 6SL3, a fourth insulating layer 6SL4, and a fifth insulating layer 6SL5. Therefore, the first conductor layer 6CL1, the first insulator layer 6SL1, the second conductor layer 6CL2, the second insulator layer 6SL2, the third conductor layer 6CL3, the third insulator layer 6SL3, the fourth conductor layer 6CL4, the fourth insulator layer 6SL4, the fifth conductor layer 6CL5, the fifth insulator layer 6SL5, and the sixth conductor layer 6CL6 are stacked in order from the compression connector 5 side upwards. The stacking direction of the contact substrate 6 coincides with the vertical direction. The second conductor layer 6CL2 is the conductor layer closest to the first conductor layer 6CL1.

[0023] Each conductive layer 6CL is typically formed of highly conductive copper foil. Each insulating layer 6SL is typically formed of glass epoxy.

[0024] Similarly, the mounting substrate 7 is a multilayer substrate in which multiple conductor layers 7CL and multiple insulating layers 7SL are alternately stacked. The multiple conductor layers 7CL include, in order from the compression connector 5 side downwards, a first conductor layer 7CL1, a second conductor layer 7CL2, a third conductor layer 7CL3, a fourth conductor layer 7CL4, a fifth conductor layer 7CL5, and a sixth conductor layer 7CL6. The multiple insulating layers 7SL include, in order from the compression connector 5 side downwards, a first insulating layer 7SL1, a second insulating layer 7SL2, a third insulating layer 7SL3, a fourth insulating layer 7SL4, and a fifth insulating layer 7SL5. Therefore, the first conductor layer 7CL1, the first insulator layer 7SL1, the second conductor layer 7CL2, the second insulator layer 7SL2, the third conductor layer 7CL3, the third insulator layer 7SL3, the fourth conductor layer 7CL4, the fourth insulator layer 7SL4, the fifth conductor layer 7CL5, the fifth insulator layer 7SL5, and the sixth conductor layer 7CL6 are stacked in order from the compression connector 5 side downwards. The stacking direction of the mounting substrate 7 coincides with the vertical direction. The second conductor layer 7CL2 is the conductor layer closest to the first conductor layer 7CL1.

[0025] Each conductive layer 7CL is typically formed from copper foil with excellent conductivity. Each insulating layer 7SL is typically formed from glass epoxy.

[0026] <Contact substrate 6> Figures 4 to 9 show partial bottom views of the first conductor layer 6CL1, second conductor layer 6CL2, third conductor layer 6CL3, fourth conductor layer 6CL4, fifth conductor layer 6CL5, and sixth conductor layer 6CL6 of the contact substrate 6. In Figures 4 to 9, the conductor portions are hatched simply for clarity.

[0027] First, the first conductor layer 6CL1 will be described with reference to Figures 2 and 4. As shown in Figures 2 and 4, the first conductor layer 6CL1 has a plurality of electrode pads 30 that correspond to a plurality of compression contacts 11 of the compression connector 5. That is, each electrode pad 30 is configured to be in contact with the spring portion 21 of the corresponding compression contact 11. The plurality of electrode pads 30, like the plurality of compression contacts 11, constitute a plurality of pad rows.

[0028] As shown in Figure 4, each pad row consists of multiple electrode pads 30 arranged alternately in the pitch direction, with two ground pads 31 and two signal pads 32. That is, along the pitch direction, the pads are arranged in the order of ground pad 31, ground pad 31, signal pad 32, signal pad 32, ground pad 31, ground pad 31, signal pad 32, signal pad 32... In other words, two signal pads 32 for differential transmission are placed between two ground pads 31. Figure 4 shows only four electrode pads 30. The four electrode pads 30 shown in Figure 4 include two ground pads 31 and two signal pads 32 placed between the two ground pads 31. The two ground pads 31 include a first ground pad 33 and a second ground pad 34. The two signal pads 32 include a first signal pad 35 and a second signal pad 36. The first ground pad 33, the first signal pad 35, the second signal pad 36, and the second ground pad 34 are arranged in this order along the pitch direction.

[0029] The first signal pad 35 includes a spring contact portion 35A and a via connection portion 35B. The spring contact portion 35A and the via connection portion 35B are connected to each other in the width direction and are integrally formed. For the sake of explanation, the boundary 35C between the spring contact portion 35A and the via connection portion 35B is shown by a dashed line. The spring contact portion 35A includes a base portion 35D which is approximately square and a tapered portion 35E which extends from the base portion 35D in the width direction.

[0030] Similarly, the second signal pad 36 includes a spring contact portion 36A and a via connection portion 36B. The spring contact portion 36A and the via connection portion 36B are connected to each other in the width direction and are integrally formed. For ease of explanation, the boundary 36C between the spring contact portion 36A and the via connection portion 36B is shown by a dashed line. The spring contact portion 36A includes a base portion 36D which is approximately square and a tapered portion 36E which extends from the base portion 36D so as to narrow in the width direction.

[0031] The first ground pad 33 includes a spring contact portion 33A, a first via connection portion 33B, and a second via connection portion 33C. The first via connection portion 33B, the spring contact portion 33A, and the second via connection portion 33C are arranged in this order in the width direction. The spring contact portion 33A, the first via connection portion 33B, and the second via connection portion 33C are integrally formed. For the sake of explanation, the boundary 33D between the spring contact portion 33A and the first via connection portion 33B is shown with a dashed line. Similarly, the boundary 33E between the spring contact portion 33A and the second via connection portion 33C is shown with a dashed line. The spring contact portion 33A includes a base portion 33F that is approximately square, and a tapered portion 33G that extends from the base portion 33F in the width direction.

[0032] Similarly, the second ground pad 34 includes a spring contact portion 34A, a first via connection portion 34B, and a second via connection portion 34C. The first via connection portion 34B, the spring contact portion 34A, and the second via connection portion 34C are arranged in this order in the width direction. The spring contact portion 34A, the first via connection portion 34B, and the second via connection portion 34C are integrally formed. For the sake of explanation, the boundary 34D between the spring contact portion 34A and the first via connection portion 34B is shown with a dashed line. Similarly, the boundary 34E between the spring contact portion 34A and the second via connection portion 34C is shown with a dashed line. The spring contact portion 34A includes a base portion 34F that is approximately square, and a tapered portion 34G that extends from the base portion 34F in the width direction.

[0033] As shown in Figure 4, the first signal pad 35 and the second signal pad 36 have the same shape, and the first ground pad 33 and the second ground pad 34 have the same shape. The spring contact portion 35A of the first signal pad 35, the spring contact portion 36A of the second signal pad 36, the spring contact portion 33A of the first ground pad 33, and the spring contact portion 34A of the second ground pad 34 all have the same shape and are aligned in the pitch direction. The via connection portion 35B of the first signal pad 35, the via connection portion 36B of the second signal pad 36, the first via connection portion 33B of the first ground pad 33, and the first via connection portion 34B of the second ground pad 34 all have the same shape and are aligned in the pitch direction.

[0034] Continuing to refer to Figure 4, the first ground pad 33 has an inner region 33P and an outer region 33Q. The inner region 33P is the region closer to the first signal pad 35 than the bisector 33R that bisects the pad area of ​​the first ground pad 33 in the pitch direction. The outer region 33Q is the region further from the first signal pad 35 than the bisector 33R. The first ground pad 33 has a shape that is symmetrical in the pitch direction with respect to the bisector 33R.

[0035] Similarly, the second ground pad 34 has an inner region 34P and an outer region 34Q. The inner region 34P is the region closer to the second signal pad 36 than the bisector 34R that bisects the pad area of ​​the second ground pad 34 in the pitch direction. The outer region 34Q is the region further from the second signal pad 36 than the bisector 34R. The second ground pad 34 has a shape that is symmetrical in the pitch direction with respect to the bisector 34R.

[0036] Next, the sixth conductor layer 6CL6 will be described with reference to Figure 9. As shown in Figure 9, the sixth conductor layer 6CL6 has a first ground pad 43, a second ground pad 44, a first signal pad 45, and a second signal pad 46, which correspond to the first ground pad 33, the second ground pad 34, the first signal pad 35, and the second signal pad 36 shown in Figure 4, respectively.

[0037] The first ground pad 43 is composed of a first via connection 43A and a second via connection 43B. The first via connection 43A and the second via connection 43B are formed apart from each other in the width direction, but they may be formed integrally with each other.

[0038] The second ground pad 44 is composed of a first via connection 44A and a second via connection 44B. The first via connection 44A and the second via connection 44B are formed apart from each other in the width direction, but they may be formed integrally with each other.

[0039] The first via connection 43A of the first ground pad 43 is electrically connected to the first via connection 33B of the first ground pad 33 shown in Figure 4 via the via hole 50A shown in Figure 5, etc. Similarly, the second via connection 43B of the first ground pad 43 is electrically connected to the second via connection 33C of the first ground pad 33 shown in Figure 4 via the via hole 50B shown in Figure 5, etc.

[0040] The first via connection 44A of the second ground pad 44 is electrically connected to the first via connection 34B of the second ground pad 34 shown in Figure 4 via the via hole 51A shown in Figure 5, etc. Similarly, the second via connection 44B of the second ground pad 44 is electrically connected to the second via connection 34C of the second ground pad 34 shown in Figure 4 via the via hole 51B shown in Figure 5, etc.

[0041] The first signal pad 45 is electrically connected to the via connection portion 35B of the first signal pad 35 shown in Figure 4, via the via hole 52 shown in Figure 5, etc.

[0042] The second signal pad 46 is electrically connected to the via connection portion 36B of the second signal pad 36 shown in Figure 4, via the via hole 53 shown in Figure 5, etc.

[0043] Next, the second conductor layer 6CL2 to the fifth conductor layer 6CL5 will be described with reference to Figures 5 to 8. The second conductor layer 6CL2 to the fifth conductor layer 6CL5 are electrically connected to each other via via holes 50A, 50B, 51A, and 51B, and all of them function as ground layers.

[0044] As shown in Figure 5, a through-hole 55 is formed in the second conductor layer 6CL2. The through-hole 55 has an inner periphery 55A. In Figure 5, via holes 52 and 53 are located inside the inner periphery 55A of the through-hole 55. Via holes 50A and 50B, via holes 51A and 51B are located outside the inner periphery 55A of the through-hole 55. The through-hole 55 includes a rectangular portion 55B which is substantially rectangular, and two extensions 55C that extend from the rectangular portion 55B in the pitch direction. One of the two extensions 55C extends between via holes 50A and 50B, and the other extends between via holes 51A and 51B.

[0045] As shown in Figure 6, a through-hole 56 is formed in the third conductor layer 6CL3. The through-hole 56 has an inner periphery 56A. In Figure 6, via holes 52 and 53 are located inside the inner periphery 56A of the through-hole 56. Via holes 50A and 50B, via hole 51A and 51B are located outside the inner periphery 56A of the through-hole 56. The through-hole 56 is approximately rectangular in shape.

[0046] As shown in Figure 7, a through-hole 57 is formed in the fourth conductor layer 6CL4. The through-hole 57 has an inner periphery 57A. In Figure 7, via holes 52 and 53 are located inside the inner periphery 57A of the through-hole 57. Via holes 50A and 50B, via hole 51A and 51B are located outside the inner periphery 57A of the through-hole 57. The through-hole 57 is approximately rectangular in shape.

[0047] As shown in Figure 8, two through-holes 58 are formed in the fifth conductor layer 6CL5. Each through-hole 58 has an inner periphery 58A. In Figure 8, via holes 52 and 53 are located inside the inner periphery 58A of the two through-holes 58, respectively. Via holes 50A and 50B, via hole 51A and 51B are located outside the inner periphery 58A of the two through-holes 58. Each through-hole 58 is approximately circular in shape.

[0048] Figure 10 shows a projection view of the inner edges 55A of through-hole 55, 56A of through-hole 56, and 57A of through-hole 57 projected onto the first conductor layer 6CL1 to explain the positional relationship between through-holes 55, 56, and 57 on the first conductor layer 6CL1. The inner edges 55A of through-hole 55, 56A of through-hole 56, and 57A of through-hole 57 are shown as thick lines, and the first ground pad 33, second ground pad 34, first signal pad 35, and second signal pad 36 are shown as dashed lines. For ease of explanation, the outer regions 33Q of the first ground pad 33 and 34Q of the second ground pad 34 are hatched.

[0049] As shown in Figure 10, in the contact substrate 6, the through hole 55 is formed such that, when viewed from above, both the first signal pad 35 and the second signal pad 36 are located inside the inner peripheral edge 55A of the through hole 55. That is, the inner peripheral edge 55A of the through hole 55 surrounds the first signal pad 35 and the second signal pad 36. In other words, the first signal pad 35 and the second signal pad 36 overlap with a single, unbroken through hole 55.

[0050] Furthermore, when viewed along the vertical direction, the through-hole 55 is formed to overlap with the outer region 33Q of the first ground pad 33 and the outer region 34Q of the second ground pad 34. That is, one extension 55C of the through-hole 55 extends from the rectangular portion 55B across the bisector 33R in the pitch direction so as to overlap with the outer region 33Q of the first ground pad 33, and the other extension 55C extends from the rectangular portion 55B across the bisector 34R in the pitch direction so as to overlap with the outer region 34Q of the second ground pad 34.

[0051] More specifically, the rectangular portion 55B of the through hole 55 does not overlap with the first via connection portion 33B and the second via connection portion 33C of the first ground pad 33, or the first via connection portion 34B and the second via connection portion 34C of the second ground pad 34, but is in contact with the first via connection portion 33B and the second via connection portion 33C of the first ground pad 33, or the first via connection portion 34B and the second via connection portion 34C of the second ground pad 34, in the pitch direction.

[0052] The two extensions 55C of the through hole 55 do not overlap with the first via connection portion 33B and the second via connection portion 33C of the first ground pad 33, or the first via connection portion 34B and the second via connection portion 34C of the second ground pad 34, but are in contact with the first via connection portion 33B and the second via connection portion 33C of the first ground pad 33, or the first via connection portion 34B and the second via connection portion 34C of the second ground pad 34, in the width direction.

[0053] Therefore, the two dividing lines 55D that demarcate the two extensions 55C of the inner peripheral edge 55A of the through hole 55 in the pitch direction are far apart in the pitch direction from the first signal pad 35 and the second signal pad 36. This means that the second conductor layer 6CL2 is also farther away from the first signal pad 35 and the second signal pad 36 in the pitch direction. This makes it possible to suppress the decrease in differential impedance at the first signal pad 35 and the second signal pad 36.

[0054] Continuing to refer to Figure 10, in the contact substrate 6, through holes 56 and 57 are formed so that they completely overlap each other when viewed from above. That is, the inner periphery 56A of through hole 56 and the inner periphery 57A of through hole 57 overlap when viewed from above. Through hole 56 is formed so that the first signal pad 35 and the second signal pad 36 are both located inside the inner periphery 56A of through hole 56. That is, the inner periphery 56A of through hole 56 surrounds the first signal pad 35 and the second signal pad 36. In other words, the first signal pad 35 and the second signal pad 36 overlap with a single, unbroken through hole 56. The same applies to through hole 57.

[0055] <Mounted board 7> Figures 11 to 17 show partial plan views of the first conductor layer 7CL1, second conductor layer 7CL2, third conductor layer 7CL3, fourth conductor layer 7CL4, fifth conductor layer 7CL5, and sixth conductor layer 7CL6 of the mounting substrate 7. In Figures 11 to 17, the conductor portions are hatched simply for clarity.

[0056] First, the first conductor layer 7CL1 will be described with reference to Figures 1 and 11. As shown in Figures 1 and 11, the first conductor layer 7CL1 has a plurality of electrode pads 60, each corresponding to a plurality of compression contacts 11 of the compression connector 5. That is, each electrode pad 60 is configured to allow soldering of the soldering portion 20 of the corresponding compression contact 11. The plurality of electrode pads 60, like the plurality of compression contacts 11, constitute a plurality of pad rows.

[0057] As shown in Figure 11, each row of electrode pads 60 consists of two ground pads 61 and two signal pads 62 arranged alternately in the pitch direction. That is, along the pitch direction, the pads are arranged in the order of ground pad 61, ground pad 61, signal pad 62, signal pad 62, ground pad 61, ground pad 61, signal pad 62, signal pad 62... In other words, two signal pads 62 for differential transmission are placed between two ground pads 61. Figure 11 shows only four electrode pads 60. The four electrode pads 60 shown in Figure 11 include two ground pads 61 and two signal pads 62 placed between the two ground pads 61. The two ground pads 61 include a first ground pad 63 and a second ground pad 64. The two signal pads 62 include a first signal pad 65 and a second signal pad 66. The first ground pad 63, the first signal pad 65, the second signal pad 66, and the second ground pad 64 are arranged in this order along the pitch direction.

[0058] The first signal pad 65 is approximately square. The dimensions of the first signal pad 65 in the pitch direction are smaller than those of the first signal pad 35 shown in Figure 4. Similarly, the dimensions of the first signal pad 65 in the width direction are smaller than those of the first signal pad 35 shown in Figure 4.

[0059] The second signal pad 66 is approximately square. The dimensions of the second signal pad 66 in the pitch direction are smaller than those of the second signal pad 36 shown in Figure 4. Similarly, the dimensions of the second signal pad 66 in the width direction are smaller than those of the second signal pad 36 shown in Figure 4.

[0060] Thus, the reason why the first signal pads 35 and 2 signal pads 36 of the contact substrate 6 are larger than the first signal pads 65 and 2 signal pads 66 of the mounting substrate 7 is to absorb positional misalignment of the contact substrate 6 in the pitch direction and width direction relative to the compression connector 5.

[0061] Referring again to Figure 11, the first ground pad 63 and the second ground pad 64 extend in the width direction.

[0062] As shown in Figure 11, the first signal pad 35 and the second signal pad 36 have the same shape, and the first ground pad 33 and the second ground pad 34 have the same shape.

[0063] Continuing to refer to Figure 11, the first ground pad 63 has an inner region 63P and an outer region 63Q. The inner region 63P is the region closer to the first signal pad 65 than the bisector 63R that bisects the pad area of ​​the first ground pad 63 in the pitch direction. The outer region 63Q is the region further from the first signal pad 65 than the bisector 63R. The first ground pad 63 has a shape that is symmetrical in the pitch direction with respect to the bisector 63R.

[0064] Similarly, the second ground pad 64 has an inner region 64P and an outer region 64Q. The inner region 64P is the region closer to the second signal pad 66 than the bisector 64R that bisects the pad area of ​​the second ground pad 64 in the pitch direction. The outer region 64Q is the region further from the second signal pad 66 than the bisector 64R. The second ground pad 64 has a shape that is symmetrical in the pitch direction with respect to the bisector 64R.

[0065] Next, the sixth conductor layer 7CL6 will be described with reference to Figure 16. As shown in Figure 16, the sixth conductor layer 7CL6 has a first ground pad 73, a second ground pad 74, a first signal pad 75, and a second signal pad 76, which correspond to the first ground pad 63, the second ground pad 64, the first signal pad 65, and the second signal pad 66 shown in Figure 11, respectively.

[0066] The first ground pad 73 is composed of a first via connection 73A and a second via connection 73B. The first via connection 73A and the second via connection 73B are formed apart from each other in the width direction, but they may be formed integrally with each other.

[0067] The second ground pad 74 is composed of a first via connection 74A and a second via connection 74B. The first via connection 74A and the second via connection 74B are formed apart from each other in the width direction, but they may be formed integrally with each other.

[0068] The first via connection portion 73A of the first ground pad 73 is electrically connected to the end portion 63A in the width direction of the first ground pad 63 shown in Figure 11 via the via hole 80A shown in Figure 12, etc. Similarly, the second via connection portion 73B of the first ground pad 73 is electrically connected to the end portion 63A in the width direction of the first ground pad 63 shown in Figure 11 via the via hole 80B shown in Figure 12, etc.

[0069] The first via connection portion 74A of the second ground pad 74 is electrically connected to the end portion 64A in the width direction of the second ground pad 64 shown in Figure 11, via the via hole 81A shown in Figure 12, etc. Similarly, the second via connection portion 74B of the second ground pad 74 is electrically connected to the end portion 64A in the width direction of the second ground pad 64 shown in Figure 11, via the via hole 81B shown in Figure 12, etc.

[0070] The first signal pad 75 is electrically connected to the first signal pad 65 shown in Figure 11 via a via hole 82 shown in Figure 12, etc.

[0071] The second signal pad 76 is electrically connected to the second signal pad 66 shown in Figure 11 via the via hole 83 shown in Figure 12, etc.

[0072] Next, the second conductor layer 7CL2 to the fifth conductor layer 7CL5 will be described with reference to Figures 12 to 15. The second conductor layer 7CL2 to the fifth conductor layer 7CL5 are electrically connected to each other via via holes 80A, 80B, 81A, and 81B, and all of them function as ground layers.

[0073] As shown in Figure 12, a through-hole 85 is formed in the second conductor layer 7CL2. The through-hole 85 has an inner periphery 85A. In Figure 12, via holes 82 and 83 are located inside the inner periphery 85A of the through-hole 85. Via holes 80A and 80B, via hole 81A and 81B are located outside the inner periphery 85A of the through-hole 85. The through-hole 85 is approximately rectangular in shape.

[0074] As shown in Figure 13, a through-hole 86 is formed in the third conductor layer 7CL3. The through-hole 86 has an inner periphery 86A. In Figure 13, via holes 82 and 83 are located inside the inner periphery 86A of the through-hole 86. Via holes 80A and 80B, via hole 81A and 81B are located outside the inner periphery 86A of the through-hole 86. The through-hole 86 is approximately rectangular in shape.

[0075] As shown in Figure 14, a through-hole 87 is formed in the fourth conductor layer 7CL4. The through-hole 87 has an inner periphery 87A. In Figure 14, via holes 82 and 83 are located inside the inner periphery 87A of the through-hole 87. Via holes 80A and 80B, via hole 81A and 81B are located outside the inner periphery 87A of the through-hole 87. The through-hole 87 is approximately rectangular in shape.

[0076] As shown in Figure 15, two through-holes 88 are formed in the fifth conductor layer 7CL5. Each through-hole 88 has an inner periphery 88A. In Figure 15, via holes 82 and 83 are located inside the inner periphery 88A of the two through-holes 88, respectively. Via holes 80A and 80B, via hole 81A and 81B are located outside the inner periphery 88A of the two through-holes 88. Each through-hole 88 is approximately circular in shape.

[0077] Figure 17 shows a projection diagram of the inner edges 85A of through-hole 85, 86A of through-hole 86, and 87A of through-hole 87 projected onto the first conductor layer 7CL1 to explain the positional relationship between through-holes 85, 86, and 87 with respect to the first conductor layer 7CL1. The inner edges 85A of through-hole 85, 86A of through-hole 86, and 87A of through-hole 87 are shown as thick lines, and the first ground pad 63, second ground pad 64, first signal pad 65, and second signal pad 66 are shown as dashed lines.

[0078] As shown in Figure 17, in the mounting substrate 7, the through-hole 85 is formed such that, when viewed from above, both the first signal pad 65 and the second signal pad 66 are located inside the inner peripheral edge 85A of the through-hole 85. That is, the inner peripheral edge 85A of the through-hole 85 surrounds the first signal pad 65 and the second signal pad 66. In other words, the first signal pad 65 and the second signal pad 66 overlap with a single, unbroken through-hole 85.

[0079] Furthermore, when viewed along the vertical direction, the through-hole 85 is formed at a distance in the pitch direction from the first ground pad 63 and the second ground pad 64. Specifically, of the two dividing lines 85D that define the through-hole 85 in the pitch direction on the inner peripheral edge 85A of the through-hole 85, one is located between the first ground pad 63 and the first signal pad 65 in the pitch direction, and is at an equal distance from the first ground pad 63 and the first signal pad 65, while the other is located between the second ground pad 64 and the second signal pad 66 in the pitch direction, and is at an equal distance from the second ground pad 64 and the second signal pad 66.

[0080] The first signal pad 65 and the second signal pad 66 can have smaller dimensions in the pitch direction than the first signal pad 35 and the second signal pad 36 shown in Figure 10, so the differential impedance does not decrease as much due to parasitic capacitance. Therefore, the design prioritizes the electromagnetic shielding effect of the second conductor layer 7CL2 by reducing the opening area of ​​the through-hole 85 in the second conductor layer 7CL2.

[0081] Continuing to refer to Figure 17, in the mounting substrate 7, through holes 85, 86, and 87 are formed so that they completely overlap each other when viewed from above. That is, the inner periphery 85A of through hole 85, the inner periphery 86A of through hole 86, and the inner periphery 87A of through hole 87 overlap when viewed from above. Therefore, through hole 86 is formed so that the first signal pad 65 and the second signal pad 66 are both located inside the inner periphery 86A of through hole 86. In other words, the inner periphery 86A of through hole 86 surrounds the first signal pad 65 and the second signal pad 66. To put it another way, the first signal pad 65 and the second signal pad 66 overlap with a single, unbroken through hole 86. The same applies to through hole 87.

[0082] (First variation) Next, a first modified example of the first embodiment will be described with reference to Figures 18 and 19. In Figures 18 and 19, the conductive parts are hatched simply for clarity.

[0083] As shown in Figure 18, in the first modified example, the third conductor layer 6CL3 and the fourth conductor layer 6CL4 have the same configuration as the fifth conductor layer 6CL5 shown in Figure 8. That is, as shown in Figure 18, two through holes 90 are formed in the third conductor layer 6CL3 and the fourth conductor layer 6CL4. Each through hole 90 has an inner peripheral edge 90A. Via holes 52 and 53 are located inside the inner peripheral edges 90A of the two through holes 90, respectively. Via holes 50A and 50B, via hole 51A and 51B are located outside the inner peripheral edges 90A of the two through holes 90. Each through hole 90 is approximately circular in shape.

[0084] Thus, the two through-holes 90 formed in the third conductor layer 6CL3 and the fourth conductor layer 6CL4 are of the minimum necessary size so that the third conductor layer 6CL3 and the fourth conductor layer 6CL4 do not conduct electricity with the via holes 52 and 53. Consequently, when viewed along the vertical direction, the third conductor layer 6CL3 and the fourth conductor layer 6CL4 overlap with the first signal pad 35 and the second signal pad 36, which are shown by the dashed lines in Figure 18. This design prioritizes the electromagnetic shielding effect provided by the third conductor layer 6CL3 and the fourth conductor layer 6CL4.

[0085] Similarly, as shown in Figure 19, in the first modified example, the third conductor layer 7CL3 and the fourth conductor layer 7CL4 have the same configuration as the fifth conductor layer 7CL5 shown in Figure 15. That is, as shown in Figure 19, two through holes 91 are formed in the third conductor layer 7CL3 and the fourth conductor layer 7CL4. Each through hole 91 has an inner peripheral edge 91A. Via holes 82 and 83 are located inside the inner peripheral edges 91A of the two through holes 91, respectively. Via holes 80A and 80B, via hole 81A and 81B are located outside the inner peripheral edges 91A of the two through holes 91. Each through hole 91 is approximately circular in shape.

[0086] Thus, the two through-holes 91 formed in the third conductor layer 7CL3 and the fourth conductor layer 7CL4 are of the minimum necessary size so that the third conductor layer 7CL3 and the fourth conductor layer 7CL4 do not conduct electricity with the via holes 82 and 83. Consequently, when viewed along the vertical direction, the third conductor layer 7CL3 and the fourth conductor layer 7CL4 overlap with the first signal pad 65 and the second signal pad 66, which are shown by the dashed lines in Figure 19. This design prioritizes the electromagnetic shielding effect provided by the third conductor layer 7CL3 and the fourth conductor layer 7CL4.

[0087] The first modified example described above can be directly applied to the second to fifth embodiments described later.

[0088] (Second Embodiment) A second embodiment of this disclosure will be described below with reference to Figures 20 and 21. The following description will focus on the differences between this embodiment and the first embodiment, omitting any redundant descriptions.

[0089] <Contact substrate 6> Figure 20 shows a projection view of the inner edges 55A of through-hole 55, 56A of through-hole 56, and 57A of through-hole 57 projected onto the first conductor layer 6CL1 to explain the positional relationship between through-holes 55, 56, and 57 on the first conductor layer 6CL1. The inner edges 55A of through-hole 55, 56A of through-hole 56, and 57A of through-hole 57 are shown as thick lines, and the first ground pad 33, second ground pad 34, first signal pad 35, and second signal pad 36 are shown as dashed lines. For ease of explanation, the outer regions 33Q of the first ground pad 33 and 34Q of the second ground pad 34 are hatched.

[0090] As shown in Figure 20, the contact substrate 6 in this embodiment has the same configuration as the contact substrate 6 in the first embodiment shown in Figure 10.

[0091] In other words, as shown in Figure 20, in the contact substrate 6, the through hole 55 is formed such that, when viewed from above, both the first signal pad 35 and the second signal pad 36 are located inside the inner peripheral edge 55A of the through hole 55. That is, the inner peripheral edge 55A of the through hole 55 surrounds the first signal pad 35 and the second signal pad 36. In other words, the first signal pad 35 and the second signal pad 36 overlap with a single, unbroken through hole 55.

[0092] Furthermore, when viewed along the vertical direction, the through-hole 55 is formed to overlap with the outer region 33Q of the first ground pad 33 and the outer region 34Q of the second ground pad 34. That is, one extension 55C of the through-hole 55 extends from the rectangular portion 55B across the bisector 33R in the pitch direction so as to overlap with the outer region 33Q of the first ground pad 33, and the other extension 55C extends from the rectangular portion 55B across the bisector 34R in the pitch direction so as to overlap with the outer region 34Q of the second ground pad 34.

[0093] Therefore, the two dividing lines 55D that demarcate the two extensions 55C of the inner peripheral edge 55A of the through hole 55 in the pitch direction are far apart in the pitch direction from the first signal pad 35 and the second signal pad 36. This means that the second conductor layer 6CL2 is also farther away from the first signal pad 35 and the second signal pad 36 in the pitch direction. This makes it possible to suppress the decrease in differential impedance at the first signal pad 35 and the second signal pad 36.

[0094] <Mounted board 7> Figure 21 shows a projection diagram of the inner edges 85A of through-hole 85, 86A of through-hole 86, and 87A of through-hole 87 projected onto the first conductor layer 7CL1 to explain the positional relationship between through-holes 85, 86, and 87 on the first conductor layer 7CL1. The inner edges 85A of through-hole 85, 86A of through-hole 86, and 87A of through-hole 87 are shown as thick lines, and the first ground pad 63, second ground pad 64, first signal pad 65, and second signal pad 66 are shown as dashed lines. For ease of explanation, the outer regions 63Q of the first ground pad 63 and 64Q of the second ground pad 64 are hatched.

[0095] As shown in Figure 21, this embodiment differs from the first embodiment in the shape of the through-hole 85 in the second conductor layer 7CL2, while the other configurations are the same as those of the first embodiment. Specifically, the through-hole 85 in this embodiment is wider in the pitch direction compared to the through-hole 85 in the first embodiment shown in Figure 17.

[0096] That is, as shown in Figure 21, the through hole 85 includes a rectangular portion 85B which is substantially rectangular, and two extensions 85C which extend from the rectangular portion 85B in the pitch direction. One of the two extensions 85C extends to pass between via holes 80A and 80B, and the other extends to pass between via holes 81A and 81B.

[0097] Furthermore, when viewed along the vertical direction, the through-hole 85 is formed to overlap with the outer region 63Q of the first ground pad 63 and the outer region 64Q of the second ground pad 64. That is, one extension 85C of the through-hole 85 extends from the rectangular portion 85B across the bisector 63R in the pitch direction so as to overlap with the outer region 63Q of the first ground pad 63, and the other extension 85C extends from the rectangular portion 85B across the bisector 64R in the pitch direction so as to overlap with the outer region 64Q of the second ground pad 64.

[0098] Therefore, the two dividing lines 85D that demarcate the two extensions 85C of the inner peripheral edge 85A of the through hole 85 in the pitch direction are far apart in the pitch direction from the first signal pad 65 and the second signal pad 66. This means that the second conductor layer 6CL2 is also farther away from the first signal pad 65 and the second signal pad 66 in the pitch direction. This makes it possible to suppress the decrease in differential impedance at the first signal pad 65 and the second signal pad 66.

[0099] (Third embodiment) A third embodiment of this disclosure will be described below with reference to Figures 22 and 23. The following description will focus on the differences between this embodiment and the first embodiment, omitting any redundant information.

[0100] <Contact substrate 6> Figure 22 shows a projection view of the inner edges 55A of through-hole 55, 56A of through-hole 56, and 57A of through-hole 57 projected onto the first conductor layer 6CL1 to explain the positional relationship between through-holes 55, 56, and 57 on the first conductor layer 6CL1. The inner edges 55A of through-hole 55, 56A of through-hole 56, and 57A of through-hole 57 are shown as thick lines, and the first ground pad 33, second ground pad 34, first signal pad 35, and second signal pad 36 are shown as dashed lines. For ease of explanation, the outer regions 33Q of the first ground pad 33 and 34Q of the second ground pad 34 are hatched.

[0101] As shown in Figure 22, the contact substrate 6 in this embodiment has the same configuration as the contact substrate 6 in the first embodiment shown in Figure 10.

[0102] In other words, as shown in Figure 22, in the contact substrate 6, the through hole 55 is formed such that, when viewed from above, both the first signal pad 35 and the second signal pad 36 are located inside the inner peripheral edge 55A of the through hole 55. That is, the inner peripheral edge 55A of the through hole 55 surrounds the first signal pad 35 and the second signal pad 36. In other words, the first signal pad 35 and the second signal pad 36 overlap with a single, unbroken through hole 55.

[0103] Furthermore, when viewed along the vertical direction, the through-hole 55 is formed to overlap with the outer region 33Q of the first ground pad 33 and the outer region 34Q of the second ground pad 34. That is, one extension 55C of the through-hole 55 extends from the rectangular portion 55B across the bisector 33R in the pitch direction so as to overlap with the outer region 33Q of the first ground pad 33, and the other extension 55C extends from the rectangular portion 55B across the bisector 34R in the pitch direction so as to overlap with the outer region 34Q of the second ground pad 34.

[0104] Therefore, the two dividing lines 55D that demarcate the two extensions 55C of the inner peripheral edge 55A of the through hole 55 in the pitch direction are far apart in the pitch direction from the first signal pad 35 and the second signal pad 36. This means that the second conductor layer 6CL2 is also farther away from the first signal pad 35 and the second signal pad 36 in the pitch direction. This makes it possible to suppress the decrease in differential impedance at the first signal pad 35 and the second signal pad 36.

[0105] <Mounted board 7> Figure 23 shows a projection view of the inner edges 85A of through-hole 85, 86A of through-hole 86, and 87A of through-hole 87 projected onto the first conductor layer 7CL1 to explain the positional relationship between through-holes 85, 86, and 87 on the first conductor layer 7CL1. The inner edges 85A of through-hole 85, 86A of through-hole 86, and 87A of through-hole 87 are shown as thick lines, and the first ground pad 63, second ground pad 64, first signal pad 65, and second signal pad 66 are shown as dashed lines. For ease of explanation, the inner region 63P and outer region 63Q of the first ground pad 63 and the inner region 64P and outer region 64Q of the second ground pad 64 are hatched.

[0106] As shown in Figure 23, this embodiment differs from the first embodiment in the shape of the through-hole 85 in the second conductor layer 7CL2, while the other configurations are the same as those of the first embodiment. Specifically, the through-hole 85 in this embodiment is wider in the pitch direction compared to the through-hole 85 in the first embodiment shown in Figure 17.

[0107] Specifically, as shown in Figure 23, the through-hole 85 is formed so as not to overlap with the outer region 63Q of the first ground pad 63 and the outer region 64Q of the second ground pad 64 when viewed along the vertical direction. Furthermore, the through-hole 85 is formed so as not to overlap with the inner region 63P of the first ground pad 63 and the inner region 64P of the second ground pad 64 when viewed along the vertical direction. However, the through-hole 85 extends in the pitch direction so as to be in contact with the inner region 63P of the first ground pad 63 and the inner region 64P of the second ground pad 64 when viewed along the vertical direction.

[0108] Specifically, one of the two dividing lines 85D that demarcate the through-hole 85 in the pitch direction on the inner peripheral edge 85A of the through-hole 85 overlaps with the contour 63S of the first ground pad 63 on the first signal pad 65 side, and the other overlaps with the contour 64S of the second ground pad 64 on the second signal pad 66 side. In this way, the second conductor layer 6CL2 is positioned away from the first signal pad 65 and the second signal pad 66 in the pitch direction, thereby suppressing the decrease in differential impedance in the first signal pad 65 and the second signal pad 66, while also reducing the opening area of ​​the through-hole 85 in the second conductor layer 7CL2 to ensure the electromagnetic shielding effect of the second conductor layer 7CL2.

[0109] However, in this embodiment, the through-hole 85 may be formed such that, when viewed along the vertical direction, it does not overlap with the outer region 63Q of the first ground pad 63 and the outer region 64Q of the second ground pad 64, but overlaps with the inner region 63P of the first ground pad 63 and the inner region 64P of the second ground pad 64. That is, the through-hole 85 may overlap with the inner region 63P beyond the contour 63S of the first ground pad 63 in the pitch direction, and may overlap with the inner region 64P beyond the contour 64S of the second ground pad 64 in the pitch direction. Even in this case, it is possible to achieve both the effect of suppressing the decrease in differential impedance in the first signal pad 65 and the second signal pad 66 and the electromagnetic shielding effect of the second conductor layer 7CL2.

[0110] (Fourth Embodiment) A fourth embodiment of this disclosure will be described below with reference to Figures 24 and 25. The following description will focus on the differences between this embodiment and the first embodiment, omitting any redundant descriptions.

[0111] <Contact substrate 6> Figure 24 shows a projection view of the inner edges 55A of through-hole 55, 56A of through-hole 56, and 57A of through-hole 57 projected onto the first conductor layer 6CL1 to explain the positional relationship between through-holes 55, 56, and 57 on the first conductor layer 6CL1. The inner edges 55A of through-hole 55, 56A of through-hole 56, and 57A of through-hole 57 are shown as thick lines, and the first ground pad 33, second ground pad 34, first signal pad 35, and second signal pad 36 are shown as dashed lines. For ease of explanation, the inner region 33P and outer region 33Q of the first ground pad 33 and the inner region 34P and outer region 34Q of the second ground pad 34 are hatched.

[0112] As shown in Figure 24, this embodiment differs from the first embodiment in the shape of the through-hole 55 of the first conductor layer 6CL1, while the other configurations are the same as those of the first embodiment. Specifically, the through-hole 55 in this embodiment is formed to be narrower in the pitch direction compared to the through-hole 55 of the first embodiment shown in Figure 10. Furthermore, the through-hole 55 in this embodiment is substantially rectangular.

[0113] Specifically, as shown in Figure 24, the through-hole 55 is formed so as not to overlap with the outer region 33Q of the first ground pad 33 and the outer region 34Q of the second ground pad 34 when viewed along the vertical direction. However, when viewed along the vertical direction, the through-hole 55 extends in the pitch direction so as to overlap with the inner region 33P of the first ground pad 33 and the inner region 34P of the second ground pad 34. That is, the through-hole 55 crosses the contour 33S of the first ground pad 33 on the first signal pad 35 side in the pitch direction and overlaps with the inner region 33P, and also crosses the contour 34S of the second ground pad 34 on the second signal pad 36 side in the pitch direction and overlaps with the inner region 34P. In this way, by positioning the second conductor layer 6CL2 away from the first signal pad 35 and the second signal pad 36 in the pitch direction, the decrease in differential impedance in the first signal pad 35 and the second signal pad 36 is suppressed, and the opening area of ​​the through-hole 55 in the second conductor layer 6CL2 is reduced to ensure the electromagnetic shielding effect of the second conductor layer 6CL2.

[0114] However, in this embodiment, one of the two dividing lines 55D that define the through-hole 55 in the pitch direction on the inner peripheral edge 55A of the through-hole 55 may overlap with the contour 33S of the first ground pad 33, and the other may overlap with the contour 34S of the second ground pad 34. In other words, the through-hole 55 may be formed so as to be in contact with the inner region 33P of the first ground pad 33 and the inner region 34P of the second ground pad 34 when viewed along the vertical direction. Even in this case, it is possible to achieve both the effect of suppressing the decrease in differential impedance in the first signal pad 35 and the second signal pad 36 and the electromagnetic shielding effect of the second conductor layer 6CL2.

[0115] <Mounted board 7> Figure 25 shows a projection diagram of the inner edges 85A of through-hole 85, 86A of through-hole 86, and 87A of through-hole 87 projected onto the first conductor layer 7CL1 to explain the positional relationship between through-holes 85, 86, and 87 on the first conductor layer 7CL1. The inner edges 85A of through-hole 85, 86A of through-hole 86, and 87A of through-hole 87 are shown as thick lines, and the first ground pad 63, second ground pad 64, first signal pad 65, and second signal pad 66 are shown as dashed lines. For ease of explanation, the outer regions 63Q of the first ground pad 63 and 64Q of the second ground pad 64 are hatched.

[0116] As shown in Figure 25, this embodiment differs from the first embodiment in the shape of the through-hole 85 in the second conductor layer 7CL2, while the other configurations are the same as those of the first embodiment. Specifically, the through-hole 85 in this embodiment is wider in the pitch direction compared to the through-hole 85 in the first embodiment shown in Figure 17.

[0117] That is, as shown in Figure 25, the through hole 85 includes a rectangular section 85B which is substantially rectangular, and two extensions 85C which extend from the rectangular section 85B in the pitch direction. One of the two extensions 85C extends to pass between via holes 80A and 80B, and the other extends to pass between via holes 81A and 81B.

[0118] Furthermore, when viewed along the vertical direction, the through-hole 85 is formed to overlap with the outer region 63Q of the first ground pad 63 and the outer region 64Q of the second ground pad 64. That is, one extension 85C of the through-hole 85 extends from the rectangular portion 85B across the bisector 63R in the pitch direction so as to overlap with the outer region 63Q of the first ground pad 63, and the other extension 85C extends from the rectangular portion 85B across the bisector 64R in the pitch direction so as to overlap with the outer region 64Q of the second ground pad 64.

[0119] Therefore, the two dividing lines 85D that demarcate the two extensions 85C of the inner peripheral edge 85A of the through hole 85 in the pitch direction are far apart in the pitch direction from the first signal pad 65 and the second signal pad 66. This means that the second conductor layer 6CL2 is also farther away from the first signal pad 65 and the second signal pad 66 in the pitch direction. This makes it possible to suppress the decrease in differential impedance at the first signal pad 65 and the second signal pad 66.

[0120] (Fifth embodiment) A fifth embodiment of this disclosure will be described below with reference to Figures 26 and 27. The following description will focus on the differences between this embodiment and the first embodiment, omitting any redundant information.

[0121] <Contact substrate 6> Figure 26 shows a projection diagram of the inner edges 55A of through-hole 55, 56A of through-hole 56, and 57A of through-hole 57 projected onto the first conductor layer 6CL1 to explain the positional relationship between through-holes 55, 56, and 57 with respect to the first conductor layer 6CL1. The inner edges 55A of through-hole 55, 56A of through-hole 56, and 57A of through-hole 57 are shown as thick lines, and the first ground pad 33, second ground pad 34, first signal pad 35, and second signal pad 36 are shown as dashed lines.

[0122] As shown in Figure 26, this embodiment differs from the first embodiment in the shape of the through-hole 55 in the first conductor layer 6CL1, while the other configurations are the same as those of the first embodiment. Specifically, the through-hole 55 in this embodiment is formed to be narrower in the pitch direction compared to the through-hole 55 in the first embodiment shown in Figure 10. Furthermore, the through-hole 55 in this embodiment is substantially rectangular.

[0123] Specifically, as shown in Figure 26, the through-hole 55 is formed at a distance in the pitch direction from the first ground pad 33 and the second ground pad 34 when viewed along the vertical direction. Specifically, one of the two dividing lines 55D that demarcate the through-hole 55 in the pitch direction is between the first ground pad 33 and the first signal pad 35 in the pitch direction and is located at an equal distance from the first ground pad 33 and the first signal pad 35, while the other is between the second ground pad 34 and the second signal pad 36 in the pitch direction and is located at an equal distance from the second ground pad 34 and the second signal pad 36. In this way, the opening area of ​​the through-hole 55 in the second conductor layer 6CL2 is reduced, prioritizing the electromagnetic shielding effect of the second conductor layer 6CL2.

[0124] <Mounted board 7> Figure 27 shows a projection diagram of the inner edges 85A of through-hole 85, 86A of through-hole 86, and 87A of through-hole 87 projected onto the first conductor layer 7CL1 to explain the positional relationship between through-holes 85, 86, and 87 on the first conductor layer 7CL1. The inner edges 85A of through-hole 85, 86A of through-hole 86, and 87A of through-hole 87 are shown as thick lines, and the first ground pad 63, second ground pad 64, first signal pad 65, and second signal pad 66 are shown as dashed lines. For ease of explanation, the outer regions 63Q of the first ground pad 63 and 64Q of the second ground pad 64 are hatched.

[0125] As shown in Figure 27, this embodiment differs from the first embodiment in the shape of the through-hole 85 in the second conductor layer 7CL2, while the other configurations are the same as those of the first embodiment. That is, the through-hole 85 in this embodiment is wider in the pitch direction compared to the through-hole 85 in the first embodiment shown in Figure 17.

[0126] That is, as shown in Figure 27, the through hole 85 includes a rectangular portion 85B which is substantially rectangular, and two extensions 85C which extend from the rectangular portion 85B in the pitch direction. One of the two extensions 85C extends to pass between via holes 80A and 80B, and the other extends to pass between via holes 81A and 81B.

[0127] Furthermore, when viewed along the vertical direction, the through-hole 85 is formed to overlap with the outer region 63Q of the first ground pad 63 and the outer region 64Q of the second ground pad 64. That is, one extension 85C of the through-hole 85 extends from the rectangular portion 85B across the bisector 63R in the pitch direction so as to overlap with the outer region 63Q of the first ground pad 63, and the other extension 85C extends from the rectangular portion 85B across the bisector 64R in the pitch direction so as to overlap with the outer region 64Q of the second ground pad 64.

[0128] Therefore, the two dividing lines 85D that demarcate the two extensions 85C of the inner peripheral edge 85A of the through hole 85 in the pitch direction are far apart in the pitch direction from the first signal pad 65 and the second signal pad 66. This means that the second conductor layer 6CL2 is also farther away from the first signal pad 65 and the second signal pad 66 in the pitch direction. This makes it possible to suppress the decrease in differential impedance at the first signal pad 65 and the second signal pad 66.

[0129] (Comparative example) Next, a comparative example of this disclosure will be described with reference to Figures 28 and 29. The following description will focus on the differences between this comparative example and the first embodiment described above, omitting any redundant information.

[0130] Figure 28 shows a partial bottom view of the second conductor layer 6CL2, the third conductor layer 6CL3, and the fourth conductor layer 6CL4 of the contact substrate 6 in the comparative example. Figure 29 shows a partial top view of the second conductor layer 7CL2, the third conductor layer 7CL3, and the fourth conductor layer 7CL4 of the mounting substrate 7 in the comparative example. In Figures 28 and 29, the conductor portions are hatched simply for clarity.

[0131] In the comparative example, the shapes of the second conductor layer 6CL2, third conductor layer 6CL3, and fourth conductor layer 6CL4 of the contact substrate 6, and the second conductor layer 7CL2, third conductor layer 7CL3, and fourth conductor layer 7CL4 of the mounting substrate 7 are different from those of the first embodiment described above, but the other configurations are the same as those of the first embodiment.

[0132] <Contact substrate 6> As shown in Figure 28, the second conductor layer 6CL2 has two through holes 100 instead of the through hole 55 shown in Figure 5. Each through hole 100 has an inner periphery 100A. In Figure 28, via holes 52 and 53 are located inside the inner periphery 100A of the two through holes 100, respectively. Via holes 50A and 50B, via hole 51A and 51B are located outside the inner periphery 100A of the two through holes 100. Each through hole 58 is approximately circular in shape. The third conductor layer 6CL3 and the fourth conductor layer 6CL4 have the same shape as the second conductor layer 6CL2.

[0133] <Mounted board 7> As shown in Figure 29, the second conductor layer 7CL2 has two through holes 101 instead of the through hole 85 shown in Figure 12. Each through hole 101 has an inner periphery 101A. In Figure 29, via holes 82 and 83 are located inside the inner periphery 101A of the two through holes 101, respectively. Via holes 80A and 80B, via hole 81A and 81B are located outside the inner periphery 101A of the two through holes 101. Each through hole 101 is approximately circular in shape. The third conductor layer 7CL3 and the fourth conductor layer 7CL4 have the same shape as the second conductor layer 7CL2.

[0134] (First transmission signal quality analysis) Next, we analyzed the signal integrity of the differential transmission board set 4 according to the first to fifth embodiments described above. The analysis results are reported below with reference to Figures 30 to 32.

[0135] The analysis software used was Ansys HFSS®, manufactured by ANSYS Corporation. The thickness of each of the multiple conductor layers 6CL and multiple conductor layers 7CL was set to 18 micrometers, the thickness of the first insulator layer 6SL1, the fifth insulator layer 6SL5, the first insulator layer 7SL1, and the fifth insulator layer 7SL5 was set to 100 micrometers, and the thickness of the second insulator layer 6SL2, the third insulator layer 6SL3, the fourth insulator layer 6SL4, the second insulator layer 7SL2, the third insulator layer 7SL3, and the fourth insulator layer 7SL4 was set to 200 micrometers. The pitch of the multiple compression contacts 11 was set to 0.7 millimeters. In addition, in Figure 3, the first conductor layer 6CL1 and the first conductor layer 7CL1 were set to be separated by 0.7 millimeters in the vertical direction. The via holes 50A, 50B, 51A, and 51B of the contact substrate 6 shown in Figures 5 to 8 all have a diameter of 0.12 millimeters. The via holes 80A, 80B, 81A, and 81B of the mounting substrate 7 shown in Figures 12 to 15 all have a diameter of 0.15 millimeters. The dielectric constant of the insulating layers 6SL and 7SL was set to 3.5.

[0136] Figure 30 is a graph showing the analysis results of the insertion loss in differential transmission using the differential transmission board set 4. In the graph of Figure 30, the horizontal axis is frequency and the vertical axis is insertion loss. In Figure 30, approximation curves A to E correspond to the first to fifth embodiments, respectively.

[0137] Figure 31 is a graph showing the analysis results of the return loss of differential transmission using the differential transmission board set 4. In the graph of Figure 31, the horizontal axis is frequency and the vertical axis is return loss. In Figure 31, approximation curves A to E correspond to the first to fifth embodiments, respectively.

[0138] Figure 32 is a graph showing the time domain reflectometry (TDR) analysis results of differential transmission using the differential transmission board set 4. In the graph of Figure 32, the horizontal axis is time and the vertical axis is differential impedance. In Figure 32, approximation curves A to E correspond to the first to fifth embodiments, respectively. As shown in Figure 32, in the TDR analysis, the differential transmission board set 4 is designed, as an example, to have a differential impedance of 85Ω. In Figure 32, the differential impedance at 0.065 nsec on the horizontal axis represents the differential impedance at the first signal pad 35 and the second signal pad 36 of the contact board 6, and the differential impedance at 0.095 nsec on the horizontal axis represents the differential impedance at the first signal pad 65 and the second signal pad 66 of the mounting board 7.

[0139] Figure 30 shows that the differential transmission board sets 4 of the first to fifth embodiments all exhibit excellent transmission characteristics. In particular, the first to fourth embodiments show significantly less insertion loss compared to the fifth embodiment.

[0140] Figure 31 shows that the differential transmission board sets 4 of the first to fifth embodiments all exhibit excellent transmission characteristics. In particular, the first to fourth embodiments show less return loss compared to the fifth embodiment. Furthermore, the first embodiment shows particularly low return loss compared to the second to fifth embodiments.

[0141] Figure 32 shows that the differential impedance in the differential transmission board set 4 of the first to fifth embodiments falls within a narrow range of ±13Ω from the design value of 85Ω.

[0142] In Figure 32, focusing on the differential impedance where the horizontal axis is 0.065 nsec, i.e., the differential impedance at the first signal pad 35 and the second signal pad 36 of the contact substrate 6, it can be seen that the first to fourth embodiments are able to suppress the decrease in differential impedance compared to the fifth embodiment. This is thought to be because, as shown in Figure 10, for example, in the first to fourth embodiments, the inner peripheral edge 55A of the second conductor layer 6CL2, i.e., the through hole 55, was sufficiently far away from the first signal pad 35 and the second signal pad 36 of the contact substrate 6 in the pitch direction. In Figure 30, the insertion loss in the first to fourth embodiments is less than that of the fifth embodiment, which is thought to be because the decrease in differential impedance at the first signal pad 35 and the second signal pad 36 of the contact substrate 6 was effectively suppressed. Similarly, in Figure 31, the return loss in the first to fourth embodiments is less than that of the fifth embodiment, which is thought to be because the decrease in differential impedance at the first signal pad 35 and the second signal pad 36 of the contact substrate 6 was effectively suppressed.

[0143] In Figure 32, focusing on the differential impedance where the horizontal axis is 0.095 nsec, i.e., the differential impedance at the first signal pad 65 and the second signal pad 66 of the mounting substrate 7, it can be seen that the differential impedance in the first embodiment is even lower compared to the second to fifth embodiments. This is thought to be because, as shown in Figure 17, in the first embodiment, the second conductor layer 7CL2, i.e., the through-hole 85, was formed narrowly in the pitch direction. However, the decrease in differential impedance at the first signal pad 65 and the second signal pad 66 of the mounting substrate 7 is not a significant problem. This is because the decrease in differential impedance at the first signal pad 65 and the second signal pad 66 of the mounting substrate 7 is only about one-fifth of that at the first signal pad 35 and the second signal pad 36 of the contact substrate 6.

[0144] Incidentally, looking at Figure 32, focusing on the differential impedance at 0.08 nsec on the horizontal axis, i.e., the differential impedance at the compression contact 11, it can be seen that the increase in differential impedance is suppressed in the first embodiment compared to the second to fifth embodiments. As mentioned above, we believe that the underlying cause of this is that in the first embodiment, the differential impedance at 0.095 nsec on the horizontal axis, i.e., the differential impedance at the first signal pad 65 and the second signal pad 66 of the mounting board 7, is even lower than that of the second to fifth embodiments. Furthermore, as shown in Figure 31, the return loss in the first embodiment was particularly low compared to that of the second to fifth embodiments, and we believe this is because the increase in differential impedance at the compression contact 11 was suppressed in the first embodiment, as shown in Figure 32. In other words, in the first embodiment, the return loss is reduced by deliberately keeping the effect of suppressing the decrease in differential impedance at the first signal pad 65 and the second signal pad 66 of the mounting board 7 to a minimum.

[0145] (Second transmission signal quality analysis) Next, we analyzed the transmission signal quality of the differential transmission substrate set 4 in which the first modified example was applied to the first to fifth embodiments described above, and the differential transmission substrate set 4 of the comparative example. The analysis results are reported with reference to Figures 33 to 35. Note that "the first modified example being applied to the first embodiment" refers to the first modified example itself.

[0146] The analysis software used was Ansys HFSS®, manufactured by ANSYS Corporation. The thickness of each of the multiple conductor layers 6CL and multiple conductor layers 7CL was set to 18 micrometers, the thickness of the first insulator layer 6SL1, the fifth insulator layer 6SL5, the first insulator layer 7SL1, and the fifth insulator layer 7SL5 was set to 100 micrometers, and the thickness of the second insulator layer 6SL2, the third insulator layer 6SL3, the fourth insulator layer 6SL4, the second insulator layer 7SL2, the third insulator layer 7SL3, and the fourth insulator layer 7SL4 was set to 200 micrometers. The pitch of the multiple compression contacts 11 was set to 0.7 millimeters. In addition, in Figure 3, the first conductor layer 6CL1 and the first conductor layer 7CL1 were set to be separated by 0.7 millimeters in the vertical direction. The via holes 50A, 50B, 51A, and 51B of the contact substrate 6 shown in Figures 5 to 8 all have a diameter of 0.12 millimeters. The via holes 80A, 80B, 81A, and 81B of the mounting substrate 7 shown in Figures 12 to 15 all have a diameter of 0.15 millimeters. The dielectric constant of the insulating layers 6SL and 7SL was set to 3.5.

[0147] Figure 33 is a graph showing the analysis results of the insertion loss of differential transmission using the differential transmission substrate set 4. In the graph of Figure 33, the horizontal axis is frequency and the vertical axis is insertion loss. In Figure 33, approximation curve A corresponds to the first embodiment, approximation curves A through E correspond to the first to fifth embodiments with the first modified example applied, and approximation curve F corresponds to the comparative example.

[0148] Figure 34 is a graph showing the analysis results of the return loss of differential transmission using the differential transmission board set 4. In the graph of Figure 34, the horizontal axis is frequency and the vertical axis is return loss. In Figure 34, approximation curve A corresponds to the first embodiment, approximation curves A through E correspond to the first to fifth embodiments with the first modification applied, and approximation curve F corresponds to the comparative example.

[0149] Figure 35 is a graph showing the time domain reflectometry (TDR) analysis results of differential transmission using the differential transmission board set 4. In the graph of Figure 35, the horizontal axis is time and the vertical axis is differential impedance. In Figure 35, approximation curve A corresponds to the first embodiment, approximation curves A through E correspond to the first to fifth embodiments with the first modified example applied, and approximation curve F corresponds to the comparative example. As shown in Figure 35, in the TDR analysis, the differential transmission board set 4 is designed, for example, to have a differential impedance of 85Ω. In Figure 35, the differential impedance at 0.065nsec on the horizontal axis represents the differential impedance at the first signal pad 35 and the second signal pad 36 of the contact board 6, and the differential impedance at 0.095nsec on the horizontal axis represents the differential impedance at the first signal pad 65 and the second signal pad 66 of the mounting board 7.

[0150] As shown in Figure 33, when the first modified example is applied to the first to fifth embodiments, the insertion loss increases slightly, but it is considerably less than that of the comparative example.

[0151] As shown in Figure 34, when the first modified example is applied to the first to fifth embodiments, the return loss increases slightly, but it is considerably less than the return loss of the comparative example.

[0152] As shown in Figure 35, when the first modified example is applied to the first to fifth embodiments, the decrease in differential impedance at the first signal pad 35 and the second signal pad 36 of the contact substrate 6 is slightly larger, but it can be seen that it is considerably suppressed compared to the decrease in the comparative example.

[0153] Several preferred embodiments of the present disclosure have been described above.

[0154] The first to fifth embodiments described above share the following common features. Specifically, as shown in Figures 1 to 3, the differential transmission board set 4 consists of a mounting board 7 on which the compression connector 5 is mounted, and a contact board 6 that contacts the compression connector 5. The contact board 6 and the mounting board 7 are electrically connected to each other via the compression connector 5. The compression connector 5 comprises four compression contacts 11 arranged in a row, each including a soldering portion 20 and a spring portion 21, and a housing 12 that holds the four compression contacts 11. As shown in Figure 3, the mounting board 7 is a multilayer board in which multiple conductor layers 7CL and multiple insulating layers 7SL are alternately stacked. The contact board 6 is a multilayer board in which multiple conductor layers 6CL and multiple insulating layers 6SL are alternately stacked. In the mounting substrate 7, the multiple conductor layers 7CL include, in order from the compression connector 5 side, a first conductor layer 7CL1 and a second conductor layer 7CL2, in this order. In the contact substrate 6, the multiple conductor layers 6CL include, in order from the compression connector 5 side, a first conductor layer 6CL1 and a second conductor layer 6CL2, in this order. As shown in Figure 11, in the mounting substrate 7, the first conductor layer 7CL1 has four electrode pads 60 corresponding to four compression contacts 11. The four electrode pads 60 include a first signal pad 65, a second signal pad 66, a first ground pad 63, and a second ground pad 64. The first ground pad 63, first signal pad 65, second signal pad 66, and second ground pad 64 are arranged in this order along the pitch direction (first direction). The soldering portions 20 of the four compression contacts 11 can be soldered to the first ground pad 63, first signal pad 65, second signal pad 66, and second ground pad 64, respectively. As shown in Figure 4, in the contact substrate 6, the first conductor layer 6CL1 has four electrode pads 30 corresponding to four compression contacts 11. The four electrode pads 30 include a first signal pad 35, a second signal pad 36, a first ground pad 33, and a second ground pad 34. The first ground pad 33, the first signal pad 35, the second signal pad 36, and the second ground pad 34 are arranged in this order along the pitch direction (first direction). The spring portions 21 of the four compression contacts 11 can each make contact with the first ground pad 33, the first signal pad 35, the second signal pad 36, and the second ground pad 34. As shown in Figure 12, in the mounting substrate 7, the second conductor layer 7CL2 is a ground layer and has a through hole 85 formed therein. As shown in Figure 17, in the mounting substrate 7, the through hole 85 is formed such that, when viewed from the vertical direction (stacking direction), both the first signal pad 65 and the second signal pad 66 are located inside the inner peripheral edge 85A of the through hole 85. As shown in Figure 11, in the mounting substrate 7, the first ground pad 63 includes an inner region 63P that is closer to the first signal pad 65 than the bisector line 63R that bisects the pad area of ​​the first ground pad 63 in the pitch direction, and an outer region 63Q that is further from the first signal pad 65 than the bisector line 63R. In the mounted substrate 7, the second ground pad 64 includes an inner region 64P that is closer to the second signal pad 66 than the bisector line 64R that bisects the pad area of ​​the second ground pad 64 in the pitch direction, and an outer region 64Q that is further from the second signal pad 66 than the bisector line 64R. As shown in Figure 5, in the contact substrate 6, the second conductor layer 6CL2 is a ground layer and has a through hole 55 formed therein. As shown in Figure 10, in the contact substrate 6, the through hole 55 is formed such that, when viewed from the vertical direction (stacking direction), both the first signal pad 35 and the second signal pad 36 are located inside the inner peripheral edge 55A of the through hole 55. As shown in Figure 4, in the contact substrate 6, the first ground pad 33 includes an inner region 33P closer to the first signal pad 35 than the bisector line 33R that bisects the pad area of ​​the first ground pad 33 in the pitch direction, and an outer region 33Q further from the first signal pad 35 than the bisector line 33R. In the contact substrate 6, the second ground pad 34 includes an inner region 34P closer to the second signal pad 36 than the bisector line 34R that bisects the pad area of ​​the second ground pad 34 in the pitch direction, and an outer region 34Q further from the second signal pad 36 than the bisector line 34R. Furthermore, in at least one of the mounting substrate 7 and the contact substrate 6, the through-hole 85 (or through-hole 55) is formed such that, when viewed along the vertical direction, it overlaps with the outer region 63Q (or outer region 33Q) of the first ground pad 63 (or first ground pad 33) and the outer region 64Q (or outer region 34Q) of the second ground pad 64 (or second ground pad 34). With the above configuration, a differential transmission board set 4 with excellent transmission characteristics is realized, as shown in Figures 30 and 31.

[0155] The first embodiment and the third to fifth embodiments described above share the following common features. That is, as shown in Figures 20 to 27, in only one of the mounting substrate 7 and the contact substrate 6, the through-hole 85 (or through-hole 55) is formed so that, when viewed along the vertical direction, it overlaps with the outer region 63Q (or outer region 33Q) of the first ground pad 63 (or first ground pad 33) and the outer region 64Q (or outer region 34Q) of the second ground pad 64 (or second ground pad 34). That is, in the other case, the through-hole 85 (or through-hole 55) is formed compactly so that, when viewed along the vertical direction, it does not overlap with the outer region 63Q (or outer region 33Q) of the first ground pad 63 (or first ground pad 33) and the outer region 64Q (or outer region 34Q) of the second ground pad 64 (or second ground pad 34). With the above configuration, a differential transmission substrate set 4 with excellent transmission characteristics is realized, as shown in Figures 30 and 31. Furthermore, an electromagnetic shielding effect can be expected on the other side.

[0156] The first modified example described above has the following characteristics: Specifically, as shown in Figure 19, in the mounting substrate 7, the third conductor layer 7CL3 is a ground layer and overlaps the first signal pad 65 and the second signal pad 66 in the vertical direction. Also, as shown in Figure 18, in the contact substrate 6, the third conductor layer 6CL3 is a ground layer and overlaps the first signal pad 35 and the second signal pad 36 in the vertical direction. With the above configuration, a differential transmission substrate set 4 with excellent transmission characteristics is realized, as shown in Figures 33 and 34. Furthermore, an electromagnetic shielding effect can be expected in the third conductor layer 7CL3 and the third conductor layer 6CL3.

[0157] The first to fifth embodiments described above share the following common features. Specifically, as shown in Figures 13 and 14, in the mounting substrate 7, the third conductor layer 7CL3 and the fourth conductor layer 7CL4 are ground layers, and through holes 86 and 87 are formed therein, respectively. As shown in Figure 17, in the mounting substrate 7, the through hole 86 of the third conductor layer 7CL3 is formed such that, when viewed from the top and bottom, the first signal pad 65 and the second signal pad 66 are both located inside the inner peripheral edge 86A of the through hole 86. Similarly, the through hole 87 of the fourth conductor layer 7CL4 is formed such that, when viewed from the top and bottom, the first signal pad 65 and the second signal pad 66 are both located inside the inner peripheral edge 87A of the through hole 87. As shown in Figure 15, in the mounting substrate 7, the fifth conductor layer 7CL5 is a ground layer and overlaps with the first signal pad 65 and the second signal pad 66 in the top and bottom direction (please refer to Figure 19 for further understanding). Furthermore, as shown in Figures 6 and 7, in the contact substrate 6, the third conductor layer 6CL3 and the fourth conductor layer 6CL4 are ground layers, and through holes 56 and 57 are formed therein, respectively. As shown in Figure 10, in the contact substrate 6, the through hole 56 of the third conductor layer 6CL3 is formed such that, when viewed from the top and bottom, both the first signal pad 35 and the second signal pad 36 are located inside the inner peripheral edge 56A of the through hole 56. Similarly, the through hole 57 of the fourth conductor layer 6CL4 is formed such that, when viewed from the top and bottom, both the first signal pad 35 and the second signal pad 36 are located inside the inner peripheral edge 57A of the through hole 57. As shown in Figure 8, in the contact substrate 6, the fifth conductor layer 6CL5 is a ground layer and overlaps with the first signal pad 35 and the second signal pad 36 in the top and bottom direction (please refer to Figure 18 for further understanding). With the above configuration, a differential transmission board set 4 with excellent transmission characteristics is realized, as shown in Figures 30 and 31.

[0158] Furthermore, as shown in Figure 2, the compression connector 5 is composed of multiple compression contact groups 11G, each consisting of four compression contacts 11 arranged in a row.

[0159] Furthermore, the multiple conductor layers 6CL of the contact substrate 6 include, in order from the compression connector 5 side, the first conductor layer 6CL1, the second conductor layer 6CL2...the (N-1)th conductor layer, and the Nth conductor layer, in this order. However, N is a natural number of 4 or more. In each of the above embodiments, the (N-1)th conductor layer and the Nth conductor layer correspond to the fifth conductor layer 6CL5 and the sixth conductor layer 6CL6, respectively. The sixth conductor layer 6CL6 (the Nth conductor layer) includes the first signal pad 45 and the second signal pad 46 which are electrically connected to the first signal pad 35 and the second signal pad 36 of the first conductor layer 6CL1, respectively. As shown in Figures 8 and 9, the fifth conductor layer 6CL5 (the (N-1)th conductor layer) is a ground layer and overlaps with the first signal pad 45 and the second signal pad 46 of the sixth conductor layer 6CL6 in the stacking direction. With the above configuration, the electromagnetic shielding effect of the first signal pad 45 and the second signal pad 46 of the sixth conductor layer 6CL6 (nth conductive layer) can be sufficiently ensured. Similarly, the multiple conductor layers 7CL of the mounting substrate 7 include, in order from the compression connector 5 side, the first conductor layer 7CL1, the second conductor layer 7CL2...the (N-1)th conductor layer, and the Nth conductor layer, in this order. However, N is a natural number of 4 or greater. In each of the above embodiments, the (N-1)th conductor layer and the Nth conductor layer correspond to the fifth conductor layer 7CL5 and the sixth conductor layer 7CL6, respectively. The sixth conductor layer 7CL6 (the Nth conductor layer) includes the first signal pad 75 and the second signal pad 76 which are electrically connected to the first signal pad 65 and the second signal pad 66 of the first conductor layer 7CL1, respectively. As shown in Figures 15 and 16, the fifth conductor layer 7CL5 (the (N-1)th conductor layer) is a ground layer and overlaps with the first signal pad 75 and the second signal pad 76 of the sixth conductor layer 7CL6 in the stacking direction. With the above configuration, the electromagnetic shielding effect of the first signal pad 75 and the second signal pad 76 of the sixth conductor layer 7CL6 (nth conductive layer) can be sufficiently ensured. However, both the contact substrate 6 and the mounting substrate 7 may possess the characteristics of the above-described (N-1) conductor layer, or only one of the contact substrate 6 and the mounting substrate 7 may possess the characteristics of the above-described (N-1) conductor layer.

[0160] Each of the above embodiments can be modified, for example, as follows:

[0161] That is, in Figure 5, either beer hall 50A or beer hall 50B can be omitted. In Figure 5, either beer hall 51A or beer hall 51B can be omitted. In Figure 12, either beer hall 80A or beer hall 80B can be omitted. In Figure 12, either beer hall 81A or beer hall 81B can be omitted.

[0162] Furthermore, as shown in Figure 3, in each of the above embodiments, the contact substrate 6 comprises a plurality of conductor layers 6CL, namely the first to sixth conductor layers. However, instead, the contact substrate 6 may also comprise a plurality of conductor layers 6CL, namely a seventh conductor layer and an eighth conductor layer. The sixth conductor layer 6CL6, the seventh conductor layer, and the eighth conductor layer are arranged in order from the compression connector 5 side. In this case, typically, the seventh and eighth conductor layers serve as ground layers. The thickness and shape of the seventh and eighth conductor layers can be arbitrary. The same applies to the mounting substrate 7. [Explanation of Symbols]

[0163] 1. Information Processing Device 2. Differential transmission assembly (assembly) 3. Support board 4 Differential Transmission Circuit Board Set 5 Compression Connectors 6 Contact substrate 6A Bolt fastening hole 6CL Conductor Layer 6CL1 First Conductor Layer 6CL2 Second Conductor Layer 6CL3 Third Conductor Layer 6CL4 Fourth Conductor Layer 6CL5 Fifth Conductor Layer 6CL6 Sixth Conductor Layer 6SL Insulating Layer 6SL1 First Insulating Layer 6SL2 Second Insulating Layer 6SL3 Third Insulating Layer 6SL4 Fourth Insulating Layer 6SL5 Fifth Insulating Layer 7. Implemented circuit board 7A Bolt fastening hole 7CL Conductor Layer 7CL1 First Conductor Layer 7CL2 Second Conductor Layer 7CL3 Third Conductor Layer 7CL4 Fourth Conductor Layer 7CL5 Fifth Conductor Layer 7CL6 Sixth Conductor Layer 7SL insulation layer 7SL1 First Insulating Layer 7SL2 Second Insulating Layer 7SL3 Third Insulating Layer 7SL4 Fourth Insulating Layer 7SL5 Fifth Insulating Layer 8 Board body 9 nuts 10 volts 11 Compression Contact 11G Compression Contact Group 12 Housing 12A Contact Room 13 Contact Columns 20 Soldering section 21 Spring section 21A contact part 22 Press-fit section 30 electrode pads 31 Groundpad 32 signal pads 33. Groundpad No. 1 33A Spring contact area 33B First via connection 33C Second via connection 33D boundary 33E Boundary 33F Base section 33G Tapered section 33P inner area 33Q outer area 33R Bisector 33S Outline 34. Second Ground Pad 34A Spring contact area 34B First via connection 34C Second via connection 34D border 34E Boundary 34F Base section 34G Tapered section 34P inner area 34Q outer area 34R Bisector 34S Outline 35. First signal pad 35A Spring contact part 35B Via connection 35C boundary 35D Base 35E Tapered section 36. Second signal pad 36A Spring contact part 36B Via connection 36C Boundary 36D Base 36E Tapered section 43. Groundpad 1 43A First via connection 43B Second via connection 44. Second Ground Pad 44A First via connection 44B Second via connection 45 First signal pad 46. ​​Second signal pad 50A Beer Hall 50B Beer Hall 51A Beer Hall 51B Beer Hall 52 Beer Hall 53 Beer Hall 55 Through hole 55A Inner periphery 55B Rectangular part 55C Extension 55D lane markings 56 Through hole 56A Inner periphery 57 Through hole 57A Inner periphery 58 Through hole 58A Inner periphery 60 electrode pads 61 Ground Pad 62 signal pads 63. Groundpad 1 63A End 63P inner area 63Q outer area 63R Bisector 63S Outline 64. Second Ground Pad 64A End 64P inner area 64Q outer area 64R Bisector 64S Outline 65 First signal pad 66 Second signal pad 73. Groundpad No. 1 73A Via 1 connection 73B Second via connection 74. Second Ground Pad 74A First via connection 74B Second via connection 75 First signal pad 76 Second signal pad 80B Beer Hall 80A Beer Hall 81A Beer Hall 81B Beer Hall 82 Beer Hall 83 Beer Hall 85 Through hole 85A Inner periphery 85B Rectangular part 85C extension 85D lane markings 86 Through hole 86A Inner periphery 87 Through hole 87A Inner periphery 88 Through hole 88A Inner periphery 90 Through hole 90A Inner periphery 91 Through hole 91A Inner periphery 100 through holes 100A Inner Circumference 101 Through hole 101A Inner periphery

Claims

1. A differential transmission board set comprising two differential transmission boards electrically connected to each other via a compression connector, each having four compression contacts arranged in a row, including a soldering portion and a spring portion, and a housing that holds the four compression contacts, The two differential transmission boards include a mounting board on which the compression connector is mounted and a contact board that contacts the compression connector. Both the mounting substrate and the contact substrate are multilayer substrates in which a plurality of conductive layers and a plurality of insulating layers are alternately stacked. In both the mounting substrate and the contact substrate, the plurality of conductor layers include, in order from the compression connector side, a first conductor layer and a second conductor layer, in this order. In both the mounting substrate and the contact substrate, the first conductor layer has four electrode pads corresponding to the four compression contacts, The four electrode pads include a first signal pad, a second signal pad, a first ground pad, and a second ground pad. The first ground pad, the first signal pad, the second signal pad, and the second ground pad are arranged in this order along the first direction. In the aforementioned mounting board, the soldering portions of the four compression contacts can be soldered to the first ground pad, the first signal pad, the second signal pad, and the second ground pad, respectively. In the contact substrate, the spring portion of the four compression contacts is capable of contacting the first ground pad, the first signal pad, the second signal pad, and the second ground pad, respectively. In both the mounting substrate and the contact substrate, the second conductor layer is a ground layer and has through holes formed therein. In both the mounting substrate and the contact substrate, the through-hole is formed such that, when viewed from the stacking direction, both the first signal pad and the second signal pad are located inside the inner peripheral edge of the through-hole. In both the mounting substrate and the contact substrate, The first ground pad includes an inner region closer to the first signal pad than the line of bisector that bisects the pad area of ​​the first ground pad in the first direction, and an outer region further from the first signal pad than the line of bisector, In both the mounting substrate and the contact substrate, The second ground pad includes an inner region closer to the second signal pad than the line of bisector that bisects the pad area of ​​the second ground pad in the first direction, and an outer region further from the second signal pad than the line of bisector, In at least one of the mounting substrate and the contact substrate, the through-hole is formed such that, when viewed along the stacking direction, it overlaps with the outer region of the first ground pad and the outer region of the second ground pad. A circuit board set for differential transmission.

2. A differential transmission substrate set according to claim 1, In only one of the mounting substrate and the contact substrate, the through-hole is formed such that, when viewed along the stacking direction, it overlaps with the outer region of the first ground pad and the outer region of the second ground pad. A circuit board set for differential transmission.

3. A differential transmission substrate set according to claim 1 or 2, In both the mounting substrate and the contact substrate, the plurality of conductor layers further include a third conductor layer, and the first conductor layer, the second conductor layer, and the third conductor layer are stacked in this order from the compression connector side. In both the mounting substrate and the contact substrate, the third conductor layer is a ground layer and overlaps with the first signal pad and the second signal pad in the stacking direction. A circuit board set for differential transmission.

4. A differential transmission substrate set according to claim 1 or 2, In both the mounting substrate and the contact substrate, the plurality of conductor layers further include a third conductor layer, a fourth conductor layer, and a fifth conductor layer, and the first conductor layer, the second conductor layer, the third conductor layer, the fourth conductor layer, and the fifth conductor layer are stacked in this order from the compression connector side. In both the mounting substrate and the contact substrate, the third conductor layer and the fourth conductor layer are ground layers and have through holes formed therein. In both the mounting substrate and the contact substrate, the through holes in the third conductor layer and the fourth conductor layer are formed such that, when viewed from the stacking direction, the first signal pad and the second signal pad are both located inside the inner peripheral edge of the through hole. In both the mounting substrate and the contact substrate, the fifth conductor layer is a ground layer and overlaps with the first signal pad and the second signal pad in the stacking direction. A circuit board set for differential transmission.

5. A differential transmission substrate set according to claim 1 or 2, This system consists of two differential transmission boards that are electrically connected to each other via a compression connector, which has multiple compression contact groups, each consisting of four compression contacts arranged in a row. A circuit board set for differential transmission.

6. A differential transmission substrate set according to claim 1 or 2, In at least one of the mounting substrate and the contact substrate, the plurality of conductor layers include, in order from the compression connector side, the first conductor layer, the second conductor layer...the (N-1)th conductor layer, the Nth conductor layer (where N is a natural number of 4 or more), in this order. The N conductor layer includes a first signal pad and a second signal pad that are electrically connected to the first signal pad and the second signal pad of the first conductor layer, respectively. The (N-1) conductor layer is a ground layer and overlaps with the first signal pad and the second signal pad of the N conductor layer in the stacking direction. A circuit board set for differential transmission.

7. A differential transmission substrate set according to claim 1 or 2, The compression connector and, including, Assembly.

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