Flexible flat conductive member

Abstract

The utility model discloses a flexible flat conductive member comprising a signal lead and a grounding lead which are arranged in parallel. The insulating layer covers the upper and lower sides of the signal lead and the grounding lead, and the insulating layer is provided with through holes located in the upper and lower sides of the grounding lead; a shielding layer covering the upper and lower sides of the insulating layer; the conductive adhesive is located in the through hole and connected with the grounding lead and the shielding layer at the same time; the signal wire and the grounding wire extend along the extending direction of the signal wire and the grounding wire and exceed the front edge of the insulating layer on at least one side to correspondingly form a signal contact pad and a grounding contact pad; the grounding wire is characterized in that the length of the conductive adhesive is greater than that of the grounding contact pad in the extension direction of the grounding wire. Through actual measurement analysis, in the extension direction of the grounding lead, the length of the conductive adhesive is larger than that of the grounding contact pad of the flexible flat conductive piece, and the crosstalk value can be reduced to meet the PCIe 5.0 requirement.

Description

[Technical field]

[0001] The utility model relates to a flexible flat conductive part, in particular to a flexible flat conductive part for improving crosstalk. [Background technology]

[0002] As the frequency of signal transmission increases, electronic components face increasingly significant electromagnetic interference problems. For flexible flat cables and flexible printed circuit boards, which generally contain multiple wires, crosstalk between different signal wires is prone to occur when transmitting high-frequency signals. Providing conductive glue on the flexible flat cable and connecting the conductive glue to the ground wire and the shielding layer at the same time can solve the crosstalk problem to a certain extent, but such a simple setting alone still cannot meet the PCIe 5.0 requirements. [Contents of the utility model]

[0003] With respect to the background technology, the applicant has found that by making the length of the conductive glue greater than the length of the ground contact pad in the extension direction of the ground wire of the flexible flat conductive member, the crosstalk value can be reduced to meet the requirements of PCIe 5.0.

[0004] In order to achieve the above purpose, the utility model adopts the following technical means:

[0005] A flexible flat conductive member comprises: a signal conductor and a ground conductor arranged in parallel with each other; an insulating layer covering the upper and lower sides of the signal conductor and the ground conductor, the insulating layer having through holes located at the upper and lower sides of the ground conductor; a shielding layer covering the upper and lower sides of the insulating layer; a conductive adhesive located in the through holes and connecting the ground conductor and the shielding layer at the same time; the signal conductor and the ground conductor extend along their own extension direction and exceed the front edge of the insulating layer on at least one side, correspondingly forming a signal contact pad and a ground contact pad; in the extension direction of the ground conductor, the length of the conductive adhesive is greater than the length of the ground contact pad.

[0006] Further, in the extending direction of the grounding wire, the distance between the conductive glue and the front edge of the insulating layer on the same side with respect to the grounding wire is smaller than the length of the conductive glue.

[0007] Furthermore, the insulating layer includes an upper insulating layer located on the upper side of the grounding wire and a lower insulating layer located on the lower side of the grounding wire, the signal wire and the grounding wire extend along their own extension direction and exceed the front edge of the upper insulating layer and do not exceed the front edge of the lower insulating layer, and a portion of the conductive glue located on the lower side of the grounding wire is located below the grounding contact pad.

[0008] Furthermore, the conductive glue located on the upper insulating layer and the conductive glue located on the lower insulating layer partially overlap each other.

[0009] Furthermore, the width of the conductive adhesive is greater than or equal to the width of the grounding wire.

[0010] Further, in the extending direction of the grounding wire, the distance between the conductive glue and the front edge of the insulating layer located on the same side with respect to the grounding wire is smaller than the length of the grounding contact pad.

[0011] Furthermore, the signal wire and the ground wire are both flat conductors whose width is greater than their thickness, and a plurality of the signal wires and the ground wires are arranged along the width direction. The flexible flat conductive part also includes a reinforcing sheet, which is located above or below the signal contact pad and the ground contact pad and between the insulating layer and the shielding layer. The reinforcing sheet has a through hole connected to the through hole, and the conductive glue extends into the through hole.

[0012] Furthermore, the length of the conductive adhesive is at least five times the center distance between the adjacent signal wires and the ground wires.

[0013] Furthermore, the signal wire and the ground wire extend beyond the rear edge of the insulating layer on at least one side to form a signal contact pad and a ground contact pad respectively.

[0014] A flexible flat conductive member, comprising: a signal wire and a ground wire arranged in parallel with each other; an insulating layer, which covers the upper and lower sides of the signal wire and the ground wire, the insulating layer having through holes located on the upper and lower sides of the ground wire, and the insulating layer on at least one side is provided with a plurality of separated through holes corresponding to the same ground wire; a shielding layer, which covers the upper and lower sides of the insulating layer; a conductive glue, which is located in the through holes and connects the ground wire and the shielding layer at the same time; at the butt end of the flexible flat conductive member, the signal wire and the ground wire extend along their own extension direction and exceed the front edge of at least one side of the insulating layer, correspondingly forming a signal contact pad and a ground contact pad; in the extension direction of the ground wire, the ground wire is simultaneously connected to a plurality of separated conductive glues located on its upper side and / or a plurality of separated conductive glues located on its lower side, the total length of the conductive glue on the upper side is greater than the length of the ground contact pad, and the total length of the conductive glue on the lower side is greater than the length of the ground contact pad; for a single ground wire, the closest distance between the conductive glue located on the same side and the front edge of the insulating layer is less than the total length of the plurality of conductive glues on the same side.

[0015] The above technical means have the following technical effects: after actual measurement and analysis, by making the length of the conductive glue in the extension direction of the grounding wire greater than the length of the grounding contact pad of the flexible flat conductive part, the crosstalk value can be reduced to meet the requirements of PCIe 5.0.

Brief Description of the Drawings

[0016] Figure 1 It is an exploded schematic diagram of a first embodiment of the flexible flat conductive member of the utility model;

[0017] Figure 2 It is an exploded schematic diagram of another perspective of the first embodiment of the flexible flat conductive element of the utility model;

[0018] Figure 3 It is a partial top view of the first embodiment of the flexible flat conductive member of the utility model;

[0019] Figure 4 for Figure 3 Section view along line AA;

[0020] Figure 5 is a near-end crosstalk curve diagram of the first embodiment;

[0021] Figure 6 is a cross-sectional view of a second embodiment;

[0022] Figure 7 The near-end crosstalk curve is a comparative diagram of a flexible flat conductive member in which the length of the conductive adhesive is shorter than the length of the ground contact pad.

[0023] Description of Figure Numbers:

[0024] Flexible flat conductive member 1 Signal conductor 11 Signal contact pad 110

[0025] Ground conductor 12 Ground contact pad 120 Insulation layer 20

[0026] Upper insulating layer 20' Lower insulating layer 20" Through hole 21

[0027] Front edge 22 Shielding layer 30 Reinforcement plate 40

[0028] Perforation 41 Conductive adhesive 50 [Specific implementation method]

[0029] In order to facilitate a better understanding of the purpose, structure, characteristics and functions of the present invention, the present invention is further described in conjunction with the accompanying drawings and specific implementation methods.

[0030] Figures 1 to 4The flexible flat conductive member 1 shown is the first embodiment of the present invention, which includes a plurality of signal conductors 11 and a plurality of ground conductors 12 arranged in parallel with each other, an insulating layer 20 covering the upper and lower sides of the signal conductors 11 and the ground conductors 12, a shielding layer 30 covering the upper and lower sides of the insulating layer 20, and a reinforcing sheet 40 located between the insulating layer 20 and the shielding layer 30 on the lower side. In the subsequent description including other embodiments, the size of the arrangement direction of the plurality of signal conductors 11 and the plurality of ground conductors 12 is taken as the width, the size of the extension direction of the signal conductors 11 and the ground conductors 12 is taken as the length, and the size of the stacking direction of the ground conductor, the insulating layer 20, and the shielding layer 30 is taken as the thickness. In addition, the directional words such as "upper", "lower", "front", "back", "left", and "right" appearing in the present invention are for the convenience of explaining and understanding the relative position relationship of each component in the present invention, and are not intended to limit the position relationship in actual use.

[0031] like Figures 1 to 4 As shown, the plurality of signal conductors 11 and the plurality of ground conductors 12 are arranged in the form of "ground-signal-signal-ground-ground-signal-signal-ground...", and two adjacent signal conductors 11 are used to transmit a set of differential signals. The signal conductors 11 and the ground conductors 12 are both flat conductors with a width greater than a thickness, and the plurality of signal conductors 11 and the ground conductors 12 are arranged along the width direction. At the front and rear ends of the flexible flat conductive member 1, the signal conductors 11 and the ground conductors 12 extend along their own extension direction and exceed the front edge 22 of the insulating layer 20 on one side (the upper side is shown in the figure, but the utility model is not limited to this) (the front and rear ends of the flexible flat conductive member 1 in this embodiment are the same, so only the front end is shown in the figure), correspondingly forming signal contact pads 110 and ground contact pads 120 and together forming the docking end of the flexible flat conductive member 1, which is used to contact the corresponding docking terminal on the docking connector (not shown). The center distance P between the adjacent signal conductors 11 and the ground conductors 12 generally depends on the system requirements. In this embodiment, the center distance P is 0.4mm.

[0032] like Figures 1 to 4As shown, at the butt end and its vicinity, the insulating layer 20 includes an upper insulating layer 20' and a lower insulating layer 20", the upper insulating layer 20' covers the upper surfaces of the signal wire 11 and the grounding wire 12, and the lower insulating layer 20" covers the lower surfaces of the signal wire 11 and the grounding wire 12, and the upper insulating layer 20' and the lower insulating layer 20" both have through holes 21 corresponding to the grounding wire 12, so that a plurality of through holes 21 are located on the upper and lower sides of the grounding wire 12, the through holes 21 located on the upper side of the grounding wire 12 penetrate the upper insulating layer 20', and the through holes 21 located on the lower side of the grounding wire 12 penetrate the lower insulating layer 20", and the through holes 21 directly pass through the upper and lower surfaces of the grounding wire 12.

[0033] like Figure 3 As shown, the width of the through hole 21 is equal to the width of the grounding wire 12, and the through hole 21 extends in the same direction as the grounding wire 12. In the extending direction of the grounding wire 12, the length of the through hole 21 is greater than the length L2 of the grounding contact pad 120. The distance between the through hole 21 and the front edge 22 of the insulating layer 20 located on the same side of the grounding wire 12 is less than the length of the through hole 21, and also less than the length L2 of the grounding contact pad 120. The through hole 21 located on the lower side of the grounding wire 12 (i.e., located on the lower insulating layer 20") is partially located below the grounding contact pad 120. The through holes 21 on the upper and lower sides of the same grounding wire 12 partially overlap each other.

[0034] like Figure 1 , Figure 2 and Figure 4 As shown, the through hole 21 is filled with a conductive glue 50, and a plurality of the conductive glues 50 are located on the upper and lower sides of the grounding wire 12, and the conductive glue 50 simultaneously connects the grounding wire 12 and the inner surface of the shielding layer 30. The utility model does not limit the specific composition of the conductive glue 50, and technicians can select suitable conductive glue 50 on the market according to the specific manufacturing process, use environment and other requirements of the flexible flat conductive member 1.

[0035] like Figure 3 and Figure 4As shown, in the present invention, the conductive glue 50 fills the through hole 21, so the size of the conductive glue 50 is slightly smaller than the size of the through hole 21. The width of the conductive glue 50 is equal to the width of the grounding wire 12. In other embodiments, if the spacing between the grounding wire 12 and the signal wire 11 is sufficient, the width of the conductive glue 50 can be made greater than the width of the grounding wire 12, which is more conducive to reducing crosstalk. The conductive glue 50 extends in the same direction as the grounding wire 12. In the extending direction of the grounding wire 12, the length L1 of the conductive glue 50 is greater than the length L2 of the grounding contact pad 120. The distance D between the conductive glue 50 and the front edge 22 of the insulating layer 20 on the same side relative to the grounding wire 12 is less than the length L1 of the conductive glue 50 and also less than the length L2 of the grounding contact pad 120. A portion of the conductive glue 50 located at the lower side of the grounding conductor 12 (i.e., located at the lower insulating layer 20″) is located below the grounding contact pad 120. A portion of the conductive glue 50 on the upper and lower sides of the same grounding conductor 12 overlaps with each other, i.e., the conductive glue 50 located at the upper insulating layer 20′ and the conductive glue 50 located at the lower insulating layer 20″ corresponding to the same grounding conductor 12 overlap with each other. The length of the conductive glue 50 is at least five times the center distance P between the adjacent signal conductor 11 and the grounding conductor 12.

[0036] like Figure 3 and Figure 4 As shown, the shielding layer 30 also covers the conductive adhesive 50, and the shielding layer 30 extends over the conductive adhesive 50 to the front and rear edges of the insulating layer 20. The shielding layer 30 can be a conventional flexible flat conductive member 1, such as a general aluminum foil shielding layer 30.

[0037] like Figure 2 and Figure 4 As shown, the reinforcing sheet 40 is arranged at the front and rear ends of the flexible flat conductive member 1, and the hardness of the reinforcing sheet 40 is greater than the hardness of the insulating layer 20, so as to appropriately increase the mechanical strength of the front and rear ends of the flexible flat conductive member 1, so as to facilitate the flexible flat conductive member 1 to be connected to the docking connector. In this embodiment, the reinforcing sheet 40 is located below the signal contact pad 110 and the ground contact pad 120, and between the lower insulating layer 20" and the shielding layer 30. The reinforcing sheet 40 has a through hole 41 connected to the through hole 21, and the conductive glue 50 extends into the through hole 41. In other embodiments, the reinforcing sheet 40 can be arranged above the signal contact pad 110 and the ground contact pad 120.

[0038] Specifically, in this embodiment, the total length of the flexible flat conductive member 1 is 6 inches, the ground contact pad 120 and the signal contact pad 110 are of equal length and 1.5 mm in length, the length of the conductive adhesive 50 and the through hole 21 is 4 mm, and the distance D between the conductive adhesive 50 and the through hole 21 and the edge of the insulating layer 20 on the same side is 0.5 mm. The ground contact pad 120 and the signal contact pad 110 with a length of 1.5 mm are sufficient to stably connect to the docking terminal of the docking connector. For this embodiment, the measured near-end crosstalk curve is referenced Figure 5 , Figure 5 The horizontal axis is the frequency in GHz, and the vertical axis is the near-end crosstalk amplitude in dB. Figure 5 The two curves in are the near-end crosstalk curves of the two signal conductors 11 in this embodiment, and the black straight line is the upper limit of the near-end crosstalk amplitude required when the product transmits PCIe 5.0 signals. The ccICN (component contribution Integrated Crosstalk Noise) obtained from the two near-end crosstalk curves are 0.31mV and 0.34mV respectively, both of which are less than the 0.5mV required by the product when transmitting PCIe 5.0 signals. For the calculation method of ccICN, please refer to the paper "Generalized ccICN (component contribution Integrated Crosstalk Noise) for PAM-N" published by the Institute of Electrical and Electronics Engineers (IEEE).

[0039] Figure 7 The near-end crosstalk curve of the comparative example is that the ground contact pad 120 and the signal contact pad 110 are of equal length and 1.5 mm, the length of the conductive adhesive 50 and the through hole 21 is 1 mm, and the other conditions are the same. Figure 5 and Figure 7 , in the range of 0 to 10 GHz, Figure 7 The curve goes beyond the black straight line. Figure 5 The curve is lower than the black straight line, obviously within the above range. Figure 7 The maximum near-end crosstalk amplitude is greater than Figure 5 The maximum near-end crosstalk amplitude is calculated. Figure 7 The ccICN of the curve is 0.59mV, which is greater than the 0.5mV required by the product when transmitting PCIe 5.0 signals. By comparison, it can be seen that in the extension direction of the ground wire 12, the length L1 of the conductive glue 50 is greater than the length L2 of the ground contact pad 120, which can reduce the ccICN value of the near-end crosstalk and also reduce the amplitude of the near-end crosstalk in some frequency bands.

[0040] In other embodiments, technicians can adjust the size of the conductive adhesive 50 by adjusting the size of the through hole 21 and the through hole 41 .

[0041] In other embodiments, in the extension direction of the grounding wire 12, each grounding wire 12 can be connected to multiple separated conductive adhesives 50 located on its upper side and / or multiple separated conductive adhesives 50 located on its lower side at the same time. For a single grounding wire 12, the closest distance between the conductive adhesive 50 located on the same side and the front edge 22 of the insulating layer 20 is less than the total length of the multiple conductive adhesives 50 on the same side. Figure 6 As shown, in the second embodiment, the total length of the flexible flat conductive member 1 is 6 inches, the center distance P between the adjacent signal wires 11 and the grounding wires 12 is 0.4 mm, the upper side of the grounding wire 12 is connected to the two separated through holes 21, and the upper surface of the grounding wire 12 is simultaneously connected to two separated conductive adhesives 50, each of which has a length of 1 mm, and the total length of the two conductive adhesives 50 is 2 mm, which is greater than the length of the grounding contact pad 120 of 1.5 mm, and the front edge 22 of the upper insulating layer 20' is closest to the upper insulating layer 20'. The distance between the conductive glue 50 is 0.5mm, which is less than 1.5mm of the ground contact pad 120 and less than the total length of the two conductive glues 50 of 2mm; the lower surface of the grounding wire 12 is connected to a single continuous conductive glue 50, and the length of the conductive glue 50 is 2mm, which is greater than 1.5mm of the ground contact pad 120; the front edge 22 of the lower insulating layer 20" is 0.5mm away from the conductive glue 50 in the lower insulating layer 20", which is less than 1.5mm of the length of the ground contact pad 120 and less than 2mm of the length of the conductive glue 50. For this embodiment, the measured ccICN value of the near-end crosstalk is 0.41mV, which is less than the 0.5mV required by PCIe 5.0. In other embodiments, the conductive glue 50 on the lower side can also be set to a number of separated smaller conductive glues 50 similar to the second embodiment.

[0042] In other embodiments, the signal wire 11 and the ground wire 12 may simultaneously protrude forward relative to the upper insulating layer 20' and the lower insulating layer 20" to form the suspended signal contact pad 110 and the ground contact pad 120 to facilitate welding with the docking element. In these embodiments, the length of the conductive adhesive 50 in the extension direction of the ground wire 12 may also be greater than the length of the ground contact pad 120 to reduce crosstalk.

[0043] The flexible flat conductive member 1 of the present invention can be applied as a flexible flat cable or a flexible printed circuit board, and the signal wire 11 and the ground wire 12 correspond to the core wires of the flexible flat cable or the etched wires of the flexible printed circuit board.

[0044] The flexible flat conductive member 1 of the utility model has the following beneficial effects:

[0045] (1) In the extension direction of the grounding wire 12, the length L1 of the single conductive glue 50 is made greater than the length L2 of the grounding contact pad 120 of the flexible flat conductive member 1, so that the ccICN value of the near-end crosstalk can be reduced to below 0.5mV, which meets the requirements of the product when transmitting PCIe 5.0 signals.

[0046] (2) In the extension direction of the grounding wire 12, the total length of the plurality of conductive adhesives 50 on the same side is made greater than the length L2 of the grounding contact pad 120 of the flexible flat conductive member 1, so that the ccICN value of the near-end crosstalk can be reduced to below 0.5 mV, which meets the requirements of the product when transmitting PCIe 5.0 signals.

[0047] (3) The conductive adhesive 50 is only arranged near the docking end, which can simplify the process and save the amount of the conductive adhesive 50. It can also reduce the ccICN value of the near-end crosstalk to below 0.5mV, which meets the requirements of the product when transmitting PCIe 5.0 signals.

[0048] (4) In the extending direction of the grounding wire 12, the distance D between the conductive glue 50 and the front edge 22 of the insulating layer 20 located on the same side relative to the grounding wire 12 is smaller than both the length L1 of the conductive glue 50 and the length L2 of the grounding contact pad 120. This can reduce the length of the grounding wire 12 and the shielding layer 30 protruding (open stub) toward the front edge 22 of the upper insulating layer 20' relative to the conductive glue 50, thereby reducing the antenna effect caused by the protruding portion A.

[0049] (5) A portion of the conductive adhesive 50 located at the lower side of the grounding wire 12 is located below the grounding contact pad 120 to fully utilize the space and reduce the length of the grounding wire 12 and the shielding layer 30 on the lower side protruding (open stub) relative to the conductive adhesive 50 on the lower side, thereby reducing the antenna effect caused by the protruding portion A.

[0050] (6) The smaller the center distance P between the adjacent signal wires 11 and the ground wires 12 is, the more likely it is to cause crosstalk. Setting the length of the conductive glue 50 to at least 5 times the center distance P helps reduce crosstalk.

[0051] The above detailed description is only an explanation of the preferred embodiment of the present utility model, and does not limit the patent scope of the present utility model. Therefore, all equivalent technical changes made by using the description and illustrations of the present utility model are included in the patent scope of the present utility model.

Claims

1. A flexible flat conductive member, comprising: Signal conductors and ground conductors arranged parallel to each other; An insulating layer, which covers the upper and lower sides of the signal wire and the ground wire, and the insulating layer has through holes located at the upper and lower sides of the ground wire; A shielding layer covering the upper and lower sides of the insulating layer; Conductive glue, which is located in the through hole and connects the grounding wire and the shielding layer; The signal wire and the ground wire extend along their own extension direction and exceed the front edge of the insulating layer on at least one side to form a signal contact pad and a ground contact pad respectively; The invention is characterized in that, in the extending direction of the grounding wire, the length of the conductive glue is greater than the length of the grounding contact pad.

2. The flexible flat conductive member according to claim 1, characterized in that: In the extending direction of the grounding wire, the distance between the conductive glue and the front edge of the insulating layer on the same side with respect to the grounding wire is smaller than the length of the conductive glue.

3. The flexible flat conductive member according to claim 1, characterized in that: The insulating layer includes an upper insulating layer located on the upper side of the grounding wire and a lower insulating layer located on the lower side of the grounding wire. The signal wire and the grounding wire extend along their own extension directions and exceed the front edge of the upper insulating layer but do not exceed the front edge of the lower insulating layer. A portion of the conductive glue located on the lower side of the grounding wire is located below the grounding contact pad.

4. The flexible flat conductive member according to claim 3, characterized in that: The conductive glue located on the upper insulating layer and the conductive glue located on the lower insulating layer partially overlap each other.

5. The flexible flat conductive member according to claim 1, characterized in that: The width of the conductive adhesive is greater than or equal to the width of the grounding wire.

6. The flexible flat conductive member according to claim 1, characterized in that: In the extending direction of the grounding wire, the distance between the conductive glue and the front edge of the insulating layer located on the same side with respect to the grounding wire is smaller than the length of the grounding contact pad.

7. The flexible flat conductive member according to claim 1, characterized in that: The signal wire and the ground wire are both flat conductors with a width greater than a thickness, and a plurality of the signal wires and the ground wires are arranged along the width direction. The flexible flat conductive member also includes a reinforcing sheet, which is located above or below the signal contact pad and the ground contact pad and between the insulating layer and the shielding layer. The reinforcing sheet has a through hole connected to the through hole, and the conductive glue extends into the through hole.

8. The flexible flat conductive member according to claim 1, characterized in that: The length of the conductive adhesive is at least five times the center distance between the adjacent signal wires and the ground wires.

9. The flexible flat conductive member according to claim 1, characterized in that: The signal conductor and the ground conductor extend beyond the rear edge of the insulating layer on at least one side to form a signal contact pad and a ground contact pad respectively.

10. A flexible flat conductive member, comprising: Signal conductors and ground conductors arranged parallel to each other; An insulating layer, which covers the upper and lower sides of the signal wire and the ground wire, the insulating layer having through holes located at the upper and lower sides of the ground wire, and the insulating layer on at least one side is provided with a plurality of separated through holes corresponding to the same ground wire; A shielding layer covering the upper and lower sides of the insulating layer; Conductive glue, which is located in the plurality of through holes and connects the grounding wire and the shielding layer at the same time; At the butt end of the flexible flat conductive member, the signal wire and the ground wire extend along their own extension direction and exceed the front edge of the insulating layer on at least one side, forming a signal contact pad and a ground contact pad respectively; It is characterized in that, in the extension direction of the grounding wire, the single grounding wire is simultaneously connected to multiple separated conductive glues located on its upper side and / or multiple separated conductive glues located on its lower side, the total length of the conductive glues on the upper side is greater than the length of the grounding contact pad, and the total length of the conductive glues on the lower side is greater than the length of the grounding contact pad; for the single grounding wire, the closest distance between the conductive glue located on the same side and the front edge of the insulating layer is less than the total length of the multiple conductive glues on the same side.

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