Cable assembly and method for manufacturing the same

Abstract

To prevent occurrence of crosstalk when performing high-speed signal transmission between devices arranged at distant positions on a board.SOLUTION: A cable assembly 40 that is arranged between a first connector 30 disposed in neighborhood of an ASIC 10 which is a control device on a board 20, and a second connector 80 disposed away from the control device on the board 20 includes a cable row 42 in which a plurality of twinax cables 2 each transmitting a differential signal is arranged, a paddle card board 41 provided with a signal electrode 4 to which internal conductors 21 of the plurality of twinax cables 2 are electrically connected, and a ground electrode 5 to which external conductors 23 of the plurality of twinax cables 2 are electrically connected, and hot melt materials 440 arranged on the paddle card board 41 so as to cover at least solder joint portions 29 at the tips of exposed portions of the internal conductors 21 and exposed portions of the internal conductors 21.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to high-speed signal transmission between an ASIC (application specific integrated circuit) and an optical transceiver, and more particularly to a cable assembly and a high-speed transmission device combining the cable assembly and the optical transceiver. [Background technology]

[0002] Patent Documents 1 and 2 are documents related to this type of technology. The high-speed interconnection cable assembly disclosed in Patent Document 1 arranges a twinax type bypass cable between an ASIC on a circuit board and a termination member on its periphery, connects a connector member to the termination member, and transmits a signal to an external device via the connector member. Patent Document 2 discloses an electric device in which the bypass cable on the circuit board is a communication cable including a differential pair of signal conductors, a shielding layer surrounding the signal conductors, and a cable jacket surrounding the shielding layer, and an access opening is provided in the cable jacket of the communication cable to expose a part of the shielding layer, and the access opening is electrically connected to a ground contact on the board.

[0003] The signal transmission characteristics of this type of circuit board depend on the signal frequency and the signal transmission distance, and the higher the signal frequency, the shorter the possible transmission distance. The approximate transmission speed and transmission distance for signal transmission on the board is 50 cm for 50 Gbps, 25 cm for 100 Gbps, and 12.5 cm for 200 Gbps. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] U.S. Patent No. 9011177B2 published [Patent Document 2] U.S. Patent No. 9203193B2 Publication Summary of the Invention [Problem to be solved by the invention]

[0005] Meanwhile, the inventors of the present application are attempting to develop a technology for high-speed signal transmission of 112 Gbps or more between an ASIC and an optical transceiver. However, the technologies of Patent Documents 1 and 2 simply connect the ASIC on a board to a device located away from the ASIC with a cable, and therefore, in order to transmit high-speed signals of 112 Gbps or more, unless the devices are brought closer together by about 25 cm, crosstalk cannot be sufficiently prevented, and impedance adjustment is not easy, resulting in problems with electrical characteristics.

[0006] The present invention has been made in consideration of these problems, and aims to provide a technical means for suppressing the occurrence of crosstalk when performing high-speed signal transmission between devices arranged at distant positions on a board, and for making it possible to easily adjust impedance and obtain good electrical characteristics. [Means for solving the problem]

[0007] A preferred embodiment of the cable assembly of the present invention is a cable assembly arranged between a first connector arranged in the vicinity of a control device on a board and a second connector arranged in a position away from the control device on the board, and is characterized in comprising: a cable row in which a plurality of cables are arranged, each of which transmits differential signals; a paddle card substrate on which signal electrodes to which the inner conductors of the plurality of cables are electrically connected and ground electrodes to which the outer conductors of the plurality of cables are electrically connected; and hot melt material arranged on the paddle card substrate so as to cover at least the soldered joints at the ends of the exposed portions of the inner conductors and the exposed portions of the inner conductors.

[0008] In this embodiment, the thickness of the hot melt material at the solder joint prior to the exposed portion of the inner conductor may be less than the thickness of the hot melt material disposed on the exposed portion of the inner conductor.

[0009] The paddle card may also include a ground cover that covers the internal conductor on the paddle card substrate, and the hot melt material may be positioned on the paddle card substrate so as to cover at least the exposed portion of the internal conductor inside the ground cover.

[0010] The paddle card may also include a ground cover that covers the internal conductor on the paddle card substrate, and the hot melt material may be arranged on the paddle card substrate so as to cover at least the ground cover and at least the exposed portion of the internal conductor inside the ground cover.

[0011] The paddle card substrate may further include a ground cover for covering the internal conductor, the ground covers being arranged for each channel and staggered on the front and back of the paddle card substrate, and the hot melt material may be arranged on the paddle card substrate so as to cover at least the exposed portion of the internal conductor on the inside of the ground cover.

[0012] The hot melt material may also be disposed on the paddle card substrate so as to cover at least the ground cover and at least an exposed portion of the internal conductor inside the ground cover.

[0013] Another preferred embodiment of the cable assembly of the present invention is a cable assembly arranged between a first connector arranged near a control device on a substrate and a second connector arranged away from the control device on the substrate, and is characterized in that it comprises: a cable row in which a plurality of cables are arranged, each of which transmits a differential signal; a paddle card substrate provided with signal electrodes to which the inner conductors of the plurality of cables are electrically connected, and ground electrodes to which the outer conductors of the plurality of cables are electrically connected; a plastic member arranged on the paddle card substrate, the plastic member having an outer frame portion and a plurality of inner frame portions arranged on an inner edge of the outer frame portion with a small gap therebetween; a ground cover arranged so as to cover some or all of the plurality of inner frame portions; and a potting material arranged within the inner frame portion so as to cover at least the exposed portions of the internal conductors.

[0014] In this embodiment, the ground covers may be arranged for each channel, and may be arranged alternately on the front and back of the paddle card substrate.

[0015] Another preferred embodiment of the cable assembly of the present invention is a cable assembly arranged between a first connector arranged in a position near a control device on a board and a second connector arranged in a position away from the control device on the board, and is a paddle card board comprising: a cable row in which a plurality of cables each transmitting a differential signal are arranged; signal electrodes to which the inner conductors of the plurality of cables are electrically connected; and ground electrodes arranged at a position where the outer conductor of the cable is attached and at positions that connect to the contact portions with the first connector on both sides of the signal electrode, characterized in that the ground electrodes to which the outer conductor of the cable is attached are arranged at a position on the board that is thinner than the thickness of the board on which the signal electrodes are located.

[0016] In this aspect, the ground electrode has a cable side contact portion that contacts the cable and a connector side contact portion that contacts the first connector, and the cable side contact portion and the connector side contact portion may be connected via inner layer wiring of the paddle card substrate.

[0017] The paddle card may also include a hot melt material disposed on the paddle card substrate so as to cover at least the solder joint at the tip of the exposed portion of the internal conductor and the exposed portion of the internal conductor.

[0018] The paddle card may also include a hot melt material arranged on the paddle card substrate so as to cover at least the soldered joint at the end of the exposed portion of the internal conductor and the exposed portion of the internal conductor, and a ground cover covering the internal conductor on the paddle card substrate, the ground covers being arranged for each channel and arranged alternately on the front and back of the paddle card substrate.

[0019] The connector may further include ground electrodes arranged on both sides of the signal electrode at positions that connect to the contact portions with the first connector, and ground covers arranged to cover the internal conductor.

[0020] The paddle card may also include a ground cover that covers the internal conductors on the paddle card substrate, the ground covers being arranged for each channel and alternately arranged on the front and back of the paddle card substrate.

[0021] Another preferred embodiment of the present invention is a method for manufacturing a cable assembly, which comprises soldering the tip of the exposed portion of the internal conductor onto a paddle card substrate, attaching a plastic member having an outer frame portion and a plurality of inner frame portions arranged with small gaps between them on the inner edge of the outer frame portion to the paddle card substrate, positioning a ground cover with a press fit so as to cover some or all of the plurality of inner frame portions and inserting and attaching it into a hole in the paddle card substrate, and injecting a potting material into the inner frame portions so as to cover the exposed portion of the internal conductor, and then allowing it to harden. Effect of the Invention

[0022] The cable assembly according to the present invention is a cable assembly disposed between a first connector disposed near a control device on a board and a second connector disposed away from the control device on the board, and includes a cable row in which a plurality of cables each transmitting a differential signal are arranged, a paddle card substrate provided with signal electrodes to which the inner conductors of the plurality of cables are electrically connected and ground electrodes to which the outer conductors of the plurality of cables are electrically connected, and a hot melt material disposed on the paddle card substrate so as to cover at least the soldered joints at the ends of the exposed portions of the inner conductors and the exposed portions of the inner conductors, thereby making it possible to suppress an increase in impedance when high-speed signal transmission is performed between devices disposed away from each other on the board. [Brief description of the drawings]

[0023] [Figure 1] 1 is a side view of a high-speed transmission device 1 including an ASIC 10, a first connector 30, a cable assembly 40, and a second connector 80 according to a first embodiment of the present invention. [Diagram 2] FIG. 1 is a perspective view of a cable assembly 40 according to a first embodiment of the present invention. [Diagram 3] FIG. 4 is a perspective view of the cable assembly 40 without the hot melt material 440. [Figure 4] 2 as viewed in the direction of arrow J. [Diagram 5] 13 is a diagram showing the impedance waveform of the cable assembly 40 and the impedance waveform of the cable assembly 40 without the hot melt material 440. FIG. [Figure 6] FIG. 13 is a diagram showing a cable assembly 40A according to a second embodiment of the present invention. [Figure 7] 7 is a view of FIG. 6 as seen from the direction of arrow J. [Figure 8] FIG. 13 is a diagram showing a cable assembly 40B according to a third embodiment of the present invention. [Figure 9]8 as viewed from the direction of arrow J. [Figure 10] This is a diagram of a cable assembly 40B without hot melt material 440B. [Figure 11] FIG. 11 is an exploded view of FIG. [Figure 12] 11 is a view of FIG. 10 as seen in the direction of arrow H. [Figure 13] FIG. 13 is a diagram showing a cable assembly 40C according to a fourth embodiment of the present invention. [Figure 14] FIG. 14 is an exploded view of FIG. [Figure 15] 14 is a view of FIG. 13 as seen in the direction of arrow J. [Figure 16] 14 is a view of FIG. 13 as seen in the direction of arrow H. [Figure 17] FIG. 16 is a partial cross-sectional view of FIG. [Figure 18] 13 is a diagram showing a first stage of the manufacturing process of the cable assembly 40C. [Figure 19] 13 is a diagram showing a second stage of the manufacturing process of the cable assembly 40C. FIG. [Figure 20] FIG. 13 is a diagram showing a third stage of the manufacturing process of the cable assembly 40C. [Figure 21] FIG. 13 is a diagram showing a fourth stage of the manufacturing process of the cable assembly 40C. [Figure 22] FIG. 21 is a diagram showing a comparison of FEXT when the ground cover 240 is in close contact with the ground electrode 5 of the paddle card substrate 41 at the stage shown in FIG. 20 and when it is raised by 0.05 mm. [Figure 23] 13 is a diagram showing the impedance waveform of the cable assembly 40C and the impedance waveform of the cable assembly 40C without the potting material 541. FIG. [Figure 24] FIG. 13 is a plan view of a paddle card substrate 41 according to a fifth embodiment of the present invention. [Diagram 25] 25 is a cross-sectional view of the fifth embodiment taken along line AA' in FIG. 24. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] First Embodiment A high-speed transmission device 1 including a cable assembly 40, a first connector 30, and a second connector 80 according to a first embodiment of the present invention will be described. This high-speed transmission device 1 is mounted on a network switch or a server. The high-speed transmission device 1 includes a rectangular substrate 20, an ASIC 10 and an optical transceiver 90 arranged at positions spaced apart from each other by a predetermined distance (for example, 25 cm) on the substrate 20, a first connector 30 arranged between the ASIC 10 and the optical transceiver 90, a cable assembly 40, and a second connector 80, and a cage 95 that covers the optical transceiver 90 and the second connector 80. The optical transceiver 90 is attached to the second connector 80, and performs high-speed differential transmission of 112 Gbps or more between the ASIC 10 and the optical transceiver 90 by PAM (Pulse Amplitude Modulation). In this embodiment, 16-channel differential signal transmission is possible between the ASIC 10 and the optical transceiver 90.

[0025] In the following description, the direction in which the ASIC 10 and the optical transceiver 90 are separated on the board 20 is referred to as the X direction, a direction perpendicular to the X direction is referred to as the Y direction, and a direction perpendicular to both the X direction and the Y direction is referred to as the Z direction. In addition, the -X side on which the ASIC 10 is located as viewed from the optical transceiver 90 in the X direction may be referred to as the front side, and the opposite +X side may be referred to as the rear side. In addition, the +Z side on which the ASIC 10 and the optical transceiver 90 are located as viewed from the board 20 in the Z direction may be referred to as the upper side, and the opposite -Z side may be referred to as the lower side. In addition, the +Y side as viewed from the rear side in the X direction may be referred to as the left side, and the -Y side as viewed from the rear side may be referred to as the right side.

[0026] 1, pairs of differential signal + and - terminals, each corresponding to one channel, and a ground terminal are exposed on the bottom surface of the ASIC 10. Each pair of + and - terminals and the ground terminal of the ASIC 10 are soldered to pads (not shown) of the substrate 20.

[0027] A first connector 30 is disposed at a position adjacent to the rear side of the ASIC 10 on the substrate 20. The distance between the ASIC 10 and the first connector 30 is, for example, 5 cm.

[0028] The first connector 30 has a slot 35 that penetrates a roughly rectangular parallelepiped insulator from top to bottom, 25 fine grooves on the front and rear walls of this slot 35, and contact pins are press-fitted into the 25 fine grooves.

[0029] Here, of the 25 contact pins press-fitted into the front and rear wall surfaces of the slot 35 of the first connector 30, the contact pins at both the left and right ends and every third contact pin between them are ground contact pins, and the contact pins sandwiched between the ground contact pins are differential signal contact pins. Hereinafter, the ground contact pins are labeled with the letter (G) and the differential signal contact pins are labeled with the letter (S) to distinguish between the two.

[0030] In FIG. 1, wiring is laid on the board 20 from fixed positions of the + and - terminals of the differential signal and the ground terminal of the ASIC 10 on the board 20 toward the rear, and this wiring is connected to the board side contact portions of the contact pins (G) and (S) of the first connector 30.

[0031] The second connector 80 is an insulator having the shape of a rectangular parallelepiped with one corner cut out, with a slot 85 penetrating it from front to back, 25 fine grooves provided on the upper and lower walls of this slot 85, and contact pins (G) and (S) are press-fitted into the 25 fine grooves.

[0032] The contact pins (G) and (S) of the second connector 80 are connected to the rear end of the outer conductor 23 and the rear end of the inner conductor 21 of the Twinax cable 2 via a ground electrode and a signal electrode on the connector board, respectively. A header of an optical transceiver 90 is fitted into an opening in the second connector 80 on the side opposite to the Twinax cable 2, and electrodes of the header of the optical transceiver 90 are electrically connected to the contact pins (G) and (S) of the second connector 80.

[0033] As shown in FIGS. 2, 3, and 4, the cable assembly 40 includes a cable row 42 in which eight twinax cables 2 are arranged side by side, a paddle card substrate 41, and a hot melt material 440.

[0034] The twinax cable 2 has two inner conductors 21, a dielectric 22, an outer conductor 23, and a jacket 24. The two inner conductors 21 are arranged in parallel, and each of the inner conductors 21 is covered with a dielectric 22. The two dielectrics 22 are bundled together and covered with an outer conductor 23, which is covered with a jacket 24.

[0035] The paddle card substrate 41 has a rectangular plate shape with approximately the same left-right width and thickness as the slot 35 of the first connector 30. Signal electrodes 4 and ground electrodes 5 are provided on front and rear surface layers 410 of the paddle card substrate 41.

[0036] As shown in Fig. 3, the 16 signal electrodes 4 on the front and rear surface layers 410 are arranged in pairs of two. Ground electrodes 5 are provided at positions on the surface layer 410 where the signal electrodes 4 are connected to the contact portions with the first connector 30 on both sides of the signal electrodes 4. The base of the ground electrode 5 occupies almost the entire upper surface of the signal electrodes 4 on the surface layer 410, and two first extensions 55 on both the left and right ends and seven second extensions 56 between them extend downward from this base. On the inside between the left and right first extensions 55 on the surface layer 410, the pairs of signal electrodes 4 and the second extensions 56 are alternately arranged at intervals.

[0037] The lower ends of the first extension portion 55 and the second extension portion 56 reach a position lower than the lower end of the signal electrode 4. The left-right widths of the first extension portion 55 and the second extension portion 56 become narrower on the way to the lower ends.

[0038] As shown in FIG. 2, the hot melt material 440 has a shape like a rectangular parallelepiped with a width substantially equal to that of the paddle card substrate 41 and a width slightly larger than that of the exposed portion of the internal conductor 21 of the twinax cable 2 on the surface layer 410, with one corner of the rectangular parallelepiped cut out. The cut-out portion of the hot melt material 440 forms a step portion 411. The hot melt material 440 contacts and covers the first extension portion 55 and the second extension portion 56 of the ground electrode 5 on the surface layer 410, the exposed portion of the internal conductor 21 of the signal electrode 4, and the soldered joint portion 29 beyond the exposed portion. The hot melt material 440 is formed by pouring a thermoplastic polymer into a mold placed on the surface layer 410 of the paddle card substrate 41, cooling and solidifying the polymer, and then removing the mold.

[0039] 4, the thickness of the step 411 of the hot melt material 440 is thinner than the thickness of the portion above it. The thick portion above the step 411 of the hot melt material 440 is disposed on the exposed portion of the internal conductor 21 in the paddle card substrate 41, and the step 411 is disposed on the solder joint 29 beyond the exposed portion of the internal conductor 21.

[0040] When the paddle card board 41 is inserted into the slot 35 of the first connector 30 , the contact pins of the first connector 30 come into contact with the ground electrode 5 and the signal electrode 4 on the connector side of the paddle card board 41 .

[0041] The above is the detailed configuration of this embodiment. The cable assembly 40 according to this embodiment is a cable assembly 40 arranged between a first connector 30 arranged in a position near the ASIC 10, which is a control device on the board 20, and a second connector 80 arranged in a position away from the control device on the board 20, and includes a cable row 42 in which a plurality of twinax cables 2 each transmitting a differential signal are arranged, a paddle card board 41 provided with a signal electrode 4 to which the inner conductors 21 of the plurality of twinax cables 2 are electrically connected, and a ground electrode 5 to which the outer conductors 23 of the plurality of twinax cables 2 are electrically connected, and a hot melt material 440 arranged on the paddle card board 41 so as to cover at least the solder joint 29 at the tip of the exposed portion of the inner conductor 21 and the exposed portion of the inner conductor 21. Therefore, when high-speed signal transmission is performed between the ASIC 10 arranged in a position away from the board 20 and the optical transceiver 90, an impedance increase can be suppressed. Normally, the impedance increases in the areas of the air space around the solder joints 29 and the exposed portions of the internal conductors 21, but the configuration of this embodiment can suppress the increase in impedance, thereby achieving better signal transmission characteristics.

[0042] Here, the inventor of the present application performed the following verification in order to confirm the effect of the present invention. The inventor of the present application calculated, using a TDR simulator, a TDR waveform in which the cable assembly 40 is the DUT, and a TDR waveform in which the cable assembly 40 without the hot melt material 440 is the DUT. FIG. 5 is a diagram showing the results of this simulation. The solid line in FIG. 5 is a TDR waveform of the cable assembly 40, and the dashed line is a TDR waveform in which the cable assembly 40 without the hot melt material 440 is removed. In this waveform, section E1 corresponds to the signal propagation time of the board 20, section E2 corresponds to the signal propagation time of the first connector 30, section E3 corresponds to the signal propagation time of the soldered joint 29, section E4 corresponds to the signal propagation time of the exposed portion of the inner conductor 21 of the twinax cable 2, and section E5 corresponds to the signal propagation time in the twinax cable 2.

[0043] 5, in the TDR waveform of the cable assembly 40 without the hot melt material 440, the peak impedance in section E3 is 97Ω and the peak impedance in section E4 is 128Ω, which are high, whereas in the TDR waveform of the cable assembly 40, the peak impedance in section E3 is 87Ω and the peak impedance in section E4 is 108Ω, which are low. As shown in FIGS. 2 and 4, in the cable assembly 40, the exposed portion of the inner conductor 21 of the twinax cable 2 and the soldered joint 29 beyond it are completely covered with the hot melt material 440, which is considered to contribute to the reduction of the peak impedance in sections E3 and E4. Note that the thickness of the step portion 411 of the hot melt material 440 arranged at the soldered joint 29 is made thinner than the thickness of the portion above it, thereby preventing a significant drop in the impedance in section E3.

[0044] <Second embodiment> Next, a second embodiment of the present invention will be described. Fig. 6 is a view showing a cable assembly 40A according to the second embodiment of the present invention. Fig. 7 is a view seen from the direction of arrow J in Fig. 6. In these figures, the same elements as those in the first embodiment are given the same reference numerals, and repeated explanations will be omitted.

[0045] In this embodiment, the hot melt material 440 in the first embodiment is replaced with a hot melt material 440A. The hot melt material 440A has a rectangular parallelepiped shape having a width approximately equal to that of the paddle card substrate 41 and a width slightly larger than that of the exposed portion of the internal conductor 21 of the twinax cable 2 on the surface layer 410. The hot melt material 440A contacts and covers the first extension 55 and the second extension 56 of the ground electrode 5 on the surface layer 410, the soldered joint 29, the internal conductor 21, the dielectric 22, and the external conductor 23. The hot melt material 440A is formed by pouring a thermoplastic polymer into a mold placed on the surface layer 410 of the paddle card substrate 41, cooling and solidifying it, and then removing the mold.

[0046] The above is the detailed configuration of this embodiment. According to this embodiment, when the hot melt material 440A is eliminated, if the impedance of the solder joint 29 and the exposed part of the internal conductor 21 are approximately the same, the same effect as that of the first embodiment can be obtained.

[0047] <Third embodiment> Next, a third embodiment of the present invention will be described. Fig. 8 is a view showing a cable assembly 40B according to the third embodiment of the present invention. Fig. 9 is a view of Fig. 8 as seen from the direction of arrow J. Fig. 10 is a view of cable assembly 40B without hot melt material 440B. Fig. 11 is an exploded view of Fig. 10. Fig. 12 is a view of Fig. 10 as seen from the direction of arrow H. In these figures, the same elements as those in the first and second embodiments are denoted by the same reference numerals, and repeated explanations will be omitted.

[0048] In this embodiment, the hot melt material 440 in the first embodiment is replaced with a hot melt material 440B and a ground cover 240.

[0049] Ground cover 240 is formed by bending a metal plate having a rectangular opening 245 along ridge lines on both sides of opening 245. Press-fit terminals 246 are provided on the bent end of ground cover 240.

[0050] As shown in FIG. 12, the ground covers 240 are arranged for each channel, and are arranged in a different manner on the front and back of the paddle card substrate 41. There are four ground covers 240 on each of the -X side and +X side of the paddle card substrate 41. The four ground covers 240 on the -X side are fixed to the surface layer 410 on the -X side so as to cover each pair of the internal conductor 21 and the solder joint 29 in the twinax cable 2 of the first, third, fifth, and seventh channels from the -Y side end on the -X side. The four ground covers 240 on the +X side are fixed to the surface layer 410 on the +X side so as to cover each pair of the internal conductor 21 and the solder joint 29 in the twinax cable 2 of the second, fourth, sixth, and eighth channels from the -Y side end on the +X side. The press-fit terminals 246 of the ground covers 240 are inserted into the holes of the extensions 55 and 56 of the ground electrode 5.

[0051] The hot melt material 440B contacts and covers the first extension 55 and the second extension 56 of the ground electrode 5 on the surface layer 410, the soldered joint 29, the exposed portion of the internal conductor 21 inside the ground cover 240, the dielectric 22, the external conductor 23, and the ground cover 240. The hot melt material 440B is formed by pouring a thermoplastic polymer into a mold placed on the surface layer 410 of the paddle card substrate 41, cooling and solidifying it, and then removing the mold.

[0052] The above is the detailed configuration of this embodiment. This embodiment also provides the same effects as the first and second embodiments. Furthermore, it is possible to prevent crosstalk from occurring and ensure good electrical characteristics.

[0053] <Fourth embodiment> Next, a fourth embodiment of the present invention will be described. Fig. 13 is a view showing a cable assembly 40C according to the fourth embodiment of the present invention. Fig. 14 is an exploded view of Fig. 13. Fig. 15 is a view of Fig. 13 as seen from the direction of arrow J. Fig. 16 is a view of Fig. 13 as seen from the direction of arrow H. Fig. 17 is a partial cross-sectional view of Fig. 15. In these figures, the same elements as those in the first to third embodiments are given the same reference numerals, and repeated explanations will be omitted.

[0054] In this embodiment, the hot melt material 440 in the first embodiment is replaced with a plastic member 140, a ground cover 240, and a potting material 541.

[0055] 14, the plastic member 140 has an outer frame portion 141 and eight inner frame portions 142 arranged on the inner edge of the outer frame portion 141 with small gaps 146 between them. The left-right width of the outer frame portion 141 is approximately the same as the left-right width of the paddle card substrate 41. The top-bottom width of the outer frame portion 141 is approximately the same as the top-bottom width from the tip of the soldered joint portion 29 of the inner conductor 21 of the twinax cable 2 to a part of the outer conductor 23 on the surface layer 410 of the paddle card substrate 41.

[0056] The inner frame portion 142 has two wall portions 143, left and right, which extend vertically, and a wall portion 144 that connects the two wall portions 143 in the vertical direction between their middle portions.

[0057] The -Z side surface of outer frame portion 141 and the +Z side surface of wall portion 144 are separated by a distance approximately equal to the vertical width including the exposed portion of the internal conductor 21 and the exposed portion of the dielectric portion 22 of the twinax cable 2, and a rectangular opening 145 is formed surrounded by outer frame portion 141, left and right wall portions 143 of inner frame portion 142, and wall portion 144.

[0058] In this embodiment, the four ground covers 240 on the -X side are fixed to the surface layer 410 on the -X side so as to cover the first inner frame portion 142, the third inner frame portion 142, the fifth inner frame portion 142, and the seventh inner frame portion 142 from the -Y side end of the -X side plastic member 140. The four ground covers 240 on the +X side are fixed to the surface layer 410 on the +X side so as to cover the second inner frame portion 142, the fourth inner frame portion 142, the sixth inner frame portion 142, and the eighth inner frame portion 142 from the -Y side end of the +X side plastic member 140. The press-fit terminals 246 of the ground covers 240 are inserted into the holes of the extensions 55 and 56 of the ground electrode 5.

[0059] The potting material 541 is formed by pouring and solidifying epoxy resin into each inner frame portion 142 of the plastic member 140. As the material for the potting material 541, urethane resin or silicone resin may be used instead of epoxy resin.

[0060] The potting material 541 is in contact with the internal conductor 21 on the surface layer 410 , the dielectric 22 , and the plastic member 140 , and covers the internal conductor 21 .

[0061] The cable assembly 40C is manufactured through the following steps: In the first step, as shown in Fig. 18, the outer conductor 23 is soldered to the ground electrode 5 on the surface layer of the paddle card substrate 41, and then the exposed portion of the inner conductor 21 of the Twinax cable 2 is soldered to the signal electrode 4 on the surface layer 410 of the paddle card substrate 41 to form a soldered joint 29.

[0062] As shown in FIG. 19, in the second stage, the plastic member 140 is positioned so that its -Z side end face is substantially flush with the -Z side end face of the solder joint 29, and is fixed onto the surface layer 410.

[0063] As shown in FIG. 20, in the third step, the ground cover 240 is inserted through the gap 146 between adjacent inner frame portions 142 of the plastic member 140 on the surface layer 410 of the paddle card substrate 41 into the holes of the extension portions 55 and 56 of the ground electrode 5, and the press-fit terminal 246 is inserted into the hole in the substrate.

[0064] As shown in FIG. 21, in the fourth stage, a potting material 541 is injected from the openings 145 of each inner frame portion 142 in the plastic member 140, and then cured.

[0065] The above is the detailed configuration of this embodiment. According to this embodiment, the same effects as those of the first to third embodiments can be obtained.

[0066] Here, the inventor of the present application performed the following verification to confirm the effect of the present invention. First, the inventor of the present application calculated FEXT using electromagnetic field analysis software in two cases, that is, when the ground cover 240 of the cable assembly 40C is in close contact with the ground electrode 5 of the paddle card substrate 41 and when it is raised by 0.05 mm, in a device in which the cable assembly 40C at the stage of FIG. 20 and the first connector 30 shown in FIG. 1 are connected. FIG. 22 is a diagram showing the results of this simulation. The solid line in FIG. 22 is FEXT when the ground cover 240 is in close contact with the ground electrode 5 of the paddle card substrate 41. The dashed line in FIG. 22 is FEXT when the ground cover 240 is raised by 0.05 mm from the ground electrode 5 of the paddle card substrate 41.

[0067] Referring to Figure 22, it can be seen that when the ground cover 240 is closely attached to the ground electrode 5 of the paddle card substrate 41, the FEXT is approximately 5 dB smaller in the 40 to 55 GHz and 68 to 76 GHz bands compared to when the ground cover 240 is raised 0.05 mm from the surface layer 410 of the paddle card substrate 41.

[0068] Secondly, the inventors of the present application calculated, using a TDR simulator, a TDR waveform in which the cable assembly 40C was used as the DUT, and a TDR waveform in which the cable assembly 40C without the potting material 541 was used as the DUT. FIG. 23 is a diagram showing the results of this simulation. The solid line in FIG. 23 is a TDR waveform of the cable assembly 40C, and the dashed line is a TDR waveform of the cable assembly 40C without the potting material 541. In this waveform, section E1 corresponds to the signal propagation time of the board 20, section E2 corresponds to the signal propagation time of the first connector 30, section E3 corresponds to the signal propagation time of the soldered joint 29, section E4 corresponds to the signal propagation time of the exposed portion of the inner conductor 21 of the twinax cable 2, and section E5 corresponds to the signal propagation time in the twinax cable 2.

[0069] 23, the TDR waveform of the cable assembly 40C without the potting material 541 has a high peak impedance of 123Ω in section E4, whereas the TDR waveform of the cable assembly 40C has a low peak impedance of 97Ω in section E4. As shown in FIG. 23, the cable assembly 40C has a structure in which the exposed portion of the inner conductor 21 of the twinax cable 2 is completely covered with the potting material 541, which is considered to contribute to the reduction of the peak impedance in section E4. When the potting material 541 is injected from the openings 145 of the inner frame parts 142 of the plastic member 140, the walls of the plastic member are used to stop the potting material from flowing, so that the potting material can be applied to a certain range. In addition, by attaching the ground cover 240 before injecting the potting material 541, the potting material is in close contact with the ground electrode, and good electrical characteristics can be ensured.

[0070] <Fifth embodiment> Next, a fifth embodiment of the present invention will be described. Fig. 24 is a plan view of a paddle card substrate 41 according to the fifth embodiment of the present invention. Fig. 25 is a cross-sectional view of the fifth embodiment as seen from line A-A' in Fig. 24. In these figures, the same elements as those in the first to fourth embodiments are given the same reference numerals, and repeated explanations will be omitted.

[0071] As shown in FIG. 25, this embodiment is characterized in that the paddle card substrate 41 has a step.

[0072] A step 412 having a depth approximately equal to the radius of the Twinax cable 2 is formed in the middle from the signal electrode 4 to the cable side contact portion 587 of the ground electrode 5 on the surface layer 410 of the paddle card substrate 41. The upper part of the step 412 on the paddle card substrate 41 is thinner than the lower part of the step 412.

[0073] The twinax cable 2 is positioned so that the dielectric 22 fits into the step 412, and is placed on the surface layer 410. The protruding portion of the internal conductor 21 of the twinax cable 2 is soldered to the signal electrode 4 of the paddle card substrate 41. The external conductor 23 of the twinax cable 2 is soldered to the cable side contact portion 587 of the ground electrode 5 of the paddle card substrate 41. The surface layer 410 of the paddle card substrate 41 on the left side of the step has the same pattern as the -Z side from the exposed portion of the internal conductor 21 of the twinax cable 2 in FIG. 3 (the center of E2 in FIG. 17). In addition, the ground electrode 588 on the surface layer of the paddle card substrate 41 is connected to the cable side contact portion 587 of the ground electrode 5 via the inner layer wiring of the paddle card substrate 41 (the inner layer through holes 413, 414 and the wiring layer 415).

[0074] The above is the detailed configuration of this embodiment. According to this embodiment, there is no need to bend the internal conductor 21 of the twin-ax cable 2, and it can be soldered to the signal electrode 4 of the paddle card substrate 41 in a straight shape. This simplifies the assembly process, and since the internal conductor exposed from the cable and the signal electrode 4 of the paddle card substrate 41 are substantially in the same position, the area of ​​the air layer around the exposed part of the internal conductor 21 can be made extremely narrower than that in FIG. 3, and an increase in impedance can be suppressed. This structure eliminates the need to apply a resin material such as a hot melt material or a potting material to the internal conductor 21. This improves productivity by reducing costs and shortening delivery times.

[0075] This embodiment may be modified as follows. A ground cover 240 may be disposed on the ground electrodes 5 disposed at positions that connect to the contact portions with the first connector 30 on both sides of the signal electrodes 4 of the paddle card substrate 41, so as to cover the internal conductors 21. With this structure, the press-fit terminals 246 of the ground cover 240 are press-fitted into the holes of the ground electrodes 5, so that the ground electrodes 5 and the ground cover 240 can be reliably brought into close contact with each other.

[0076] Furthermore, the ground covers 240 covering the internal conductors 21 on the paddle card substrate 41 may be arranged for each channel, and may be arranged alternately on the front and back of the paddle card substrate 41. This structure makes it possible to more effectively suppress crosstalk.

Claims

1. A cable assembly disposed between a first connector disposed near a control device on a substrate and a second connector disposed away from the control device on the substrate, a cable row including a plurality of cables arranged side by side, each of the cables transmitting a differential signal; a paddle card substrate provided with signal electrodes to which the inner conductors of the plurality of cables are electrically connected and ground electrodes to which the outer conductors of the plurality of cables are electrically connected; a hot melt material disposed on the paddle card substrate so as to cover at least the solder joints at the ends of the exposed portions of the internal conductors and the exposed portions of the internal conductors; A cable assembly comprising:

2. 2. The cable assembly of claim 1, wherein a thickness of hot melt material at a solder joint prior to the exposed portion of the inner conductor is less than a thickness of hot melt material disposed on the exposed portion of the inner conductor.

3. a ground cover covering the internal conductor on the paddle card substrate; The hot melt material is disposed on the paddle card substrate so as to cover at least the exposed portion of the inner conductor inside the ground cover.

2. The cable assembly according to claim 1.

4. a ground cover covering the internal conductor on the paddle card substrate; 4. The cable assembly of claim 3, wherein the hot melt material is disposed on the paddle card substrate so as to cover at least the ground cover and at least the exposed portion of the inner conductor inside the ground cover.

5. A ground cover covering the internal conductor on the paddle card substrate is provided for each channel, and the ground covers are arranged alternately on the front and back of the paddle card substrate; The hot melt material is disposed on the paddle card substrate so as to cover at least the exposed portion of the inner conductor inside the ground cover.

4. The cable assembly according to claim 3.

6. The hot melt material is disposed on the paddle card substrate so as to cover at least the ground cover and at least an exposed portion of the inner conductor inside the ground cover.

6. The cable assembly of claim 5, further comprising:

7. A cable assembly disposed between a first connector disposed near a control device on a substrate and a second connector disposed away from the control device on the substrate, a cable row including a plurality of cables arranged side by side, each of the cables transmitting a differential signal; a paddle card substrate provided with signal electrodes to which the inner conductors of the plurality of cables are electrically connected and ground electrodes to which the outer conductors of the plurality of cables are electrically connected; a plastic member disposed on the paddle card substrate, the plastic member having an outer frame portion and a plurality of inner frame portions arranged at an inner edge of the outer frame portion with slight gaps therebetween; A ground cover arranged to cover a part or all of the plurality of inner frame portions; a potting material disposed within the inner frame so as to cover at least an exposed portion of the internal conductor; A cable assembly comprising:

8. The ground covers are arranged for each channel, and are arranged alternately on the front and back of the paddle card substrate.

8. The cable assembly according to claim 7.

9. A cable assembly disposed between a first connector disposed near a control device on a substrate and a second connector disposed away from the control device on the substrate, a cable row including a plurality of cables arranged side by side, each of the cables transmitting a differential signal; A paddle card substrate including: a signal electrode to which the inner conductors of the plurality of cables are electrically connected; and ground electrodes disposed at a position where an outer conductor of the cable is attached and at positions on both sides of the signal electrode that are connected to a contact portion with the first connector, A cable assembly, characterized in that the ground electrode to which the outer conductor of the cable is attached is disposed at a position on the board that is thinner than the board on which the signal electrodes are disposed.

10. 10. The cable assembly of claim 9, wherein the ground electrode has a cable side contact portion that contacts the cable and a connector side contact portion that contacts the first connector, and the cable side contact portion and the connector side contact portion are connected via inner layer wiring of the paddle card substrate.

11. a hot melt material disposed on the paddle card substrate so as to cover at least the solder joints at the ends of the exposed portions of the internal conductors and the exposed portions of the internal conductors; The cable assembly of claim 9 comprising:

12. a hot melt material disposed on the paddle card substrate so as to cover at least the solder joints at the ends of the exposed portions of the internal conductors and the exposed portions of the internal conductors; a ground cover covering the internal conductor on the paddle card substrate, the ground covers being arranged for each channel and being arranged alternately on the front and back of the paddle card substrate; 10. The cable assembly of claim 9, comprising:

13. 10. The cable assembly according to claim 9, further comprising: ground electrodes arranged on both sides of the signal electrode at positions that connect to the contact portion with the first connector, and a ground cover arranged to cover the inner conductor.

14. The cable assembly of claim 13, further comprising a ground cover covering the inner conductor on the paddle card substrate, the ground covers being arranged for each channel and being arranged alternately on the front and back of the paddle card substrate.

15. Solder the exposed tip of the inner conductor onto the paddle card board. a plastic member having an outer frame portion and a plurality of inner frame portions arranged at an inner edge of the outer frame portion with a small gap therebetween, the plastic member being attached to a paddle card substrate; a ground cover having a press fit is disposed so as to cover a part or all of the plurality of inner frame portions and is inserted into the hole of the paddle card substrate and attached; A potting material is injected into the inner frame so as to cover the exposed portion of the internal conductor, and then hardened. A method for manufacturing a cable assembly comprising the steps of:

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