Differential pair structure, flat differential cable and interconnection architecture

Abstract

The invention relates to a differential pair structure, a flat differential cable and an interconnection architecture, the differential pair structure comprises a pair of conductors arranged side by side, and the pair of conductors are randomly bent in the same plane along the length direction and are arranged at equal intervals. The flat differential cable comprises at least one differential pair arranged in the same plane, an insulating layer and a shielding layer, the differential pair is of a differential pair structure, the insulating layer wraps the outer side of the differential pair to fix the differential pair, an air gap extending in the bending direction is formed between each pair of conductors, and the shielding layer is arranged on the outer side of the insulating layer. The interconnection framework comprises the flat differential cable and golden fingers which are respectively connected with two ends of the flat differential cable. According to the scheme, the differential pairs are bent at will, the transmission performance is not affected by spatial layout, air gaps are reserved between the differential pairs, and the effective dielectric constant of the insulating layer is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of cable transmission, and specifically relates to a differential pair structure, a flat differential cable, and an interconnection architecture. Background Art

[0002] Flexible flat cables are widely used in the internal wiring of electronic devices and information devices due to their space-saving and easy connection characteristics. Their common structure mainly consists of at least two rectangular conductors and an insulating layer, or a structure with a shielding layer added according to the frequency requirements of the device, as Figure 1 shown. In the application field of high-speed differential signal transmission, the existing flat cable structure cannot meet the demanding requirements of insertion loss indicators. A common improvement method is to introduce air gaps between the insulating layers of the conductors. However, the cable often needs to be bent left and right and then up and down, and this multi-bending form will make its structure and transmission performance unstable. Summary of the Invention

[0003] To solve the above technical problems, the present invention provides a differential pair structure, a flat differential cable, and an interconnection architecture, enabling the differential pair to be bent arbitrarily, satisfying that the spatial layout does not affect the transmission performance, leaving an air gap between the differential pairs, and reducing the equivalent dielectric constant of the insulating layer.

[0004] To achieve the above technical purpose, the technical solution adopted is: a differential pair structure, including a pair of conductors arranged side by side, and the pair of conductors are bent arbitrarily in the same plane along the length direction and arranged at equal intervals.

[0005] The beneficial effect of the present invention is: it meets the connection spatial layout, the cable does not need to be bent as a whole, but realizes the bending in the plane direction through the conductor bending design, makes full use of the space, reduces the amount of bending, and has stable transmission performance.

[0006] The conductor described in the present invention is a single-core conductor.

[0007] The beneficial effect of the present invention is: all the core wires in the cable adopt single-core conductors, do not need to be stranded, and can be integrally formed for transmitting high-speed signals with a transmission rate of 25 Gbps and above.

[0008] The cross-section of the conductor described in the present invention is polygonal.

[0009] The beneficial effect of the present invention is: compared with the circular conductor structure, under the condition of equal cross-sectional area, that is, equal consumption of materials, the cross-sectional perimeter of the polygonal conductor is longer, making the current distribution on the outer surface layer of the conductor more uniform during signal transmission, the effective cross-sectional area of the conductor larger, thereby weakening the skin effect, reducing the power loss, and reducing the impedance of the cable.

[0010] The cross-section of the conductor described in the present invention is an axisymmetric shape.

[0011] The beneficial effects of the present invention are as follows: Making the single-core conductor into an axisymmetric shape is not only convenient for formation but also convenient for position alignment when making a multi-core wire structure cable.

[0012] A flat differential cable includes at least a pair of differential pairs arranged in the same plane, an insulating layer, and a shielding layer. The differential pair has a differential pair structure. The insulating layer is coated on the outside of the differential pair to fix the differential pair, so that an air gap extending in the bending direction is formed between each pair of conductors. A shielding layer is provided outside the insulating layer.

[0013] The beneficial effects of the present invention are as follows: When forming the flat differential cable, the differential pair structure is bent on the same plane, which can reduce the bending amount of the cable or eliminate the need for bending. Moreover, the introduction of an air gap between the differential pair structures reduces the equivalent dielectric constant of the insulating material, thereby reducing the insertion loss of the cable.

[0014] The insulating layer described in the present invention is composed of an upper insulating layer and a lower insulating layer. The upper insulating layer and the lower insulating layer are respectively arranged on the upper and lower sides of the differential pair. An adhesive layer is adhered to the lower surface of the upper insulating layer and / or the upper surface of the lower insulating layer. The upper insulating layer and the lower insulating layer are bonded through the adhesive layer to sandwich the differential pair.

[0015] The beneficial effects of the present invention are as follows: The insulating layer can be quickly formed by using the upper insulating layer and the lower insulating layer, which is convenient for production and is not affected by the bending angle of the differential pair structure. Moreover, the differential pair can be positioned first by using the adhesive layer to prevent the differential pair from shifting during the forming process.

[0016] The shielding layer described in the present invention includes an upper shielding layer and a lower shielding layer respectively located on the upper and lower sides of the insulating layer.

[0017] The beneficial effects of the present invention are as follows: The shielding layer is used to shield electromagnetic signals, improving the stability of the transmitted signal, and the double-layer shielding effect is more excellent.

[0018] The shielding layer described in the present invention is a single shielding layer provided on the upper side or the lower side of the insulating layer.

[0019] The beneficial effects of the present invention are as follows: Compared with the double-layer shielding layer, the single shielding layer can play a certain role in shielding electromagnetic signals and can save costs.

[0020] The shielding layer described in the present invention is adhered to the outside of the insulating layer through an adhesive layer.

[0021] The beneficial effects of the present invention are as follows: The adhesive layer is used to fix the shielding layer and the insulating layer, which is convenient and rapid for forming. The adhesive layer also participates in signal transmission as a medium like the insulating layer. The adhesive layer formed by a material with a low dielectric constant is beneficial to improving the signal transmission performance.

[0022] An interconnection architecture includes the flat differential cable described above, and the gold fingers respectively connected to both ends of the flat differential cable.

[0023] The beneficial effects of the present invention are as follows: An air gap is filled between each differential conductor. The introduction of the air gap reduces the equivalent dielectric constant of the insulating material, thereby reducing the insertion loss of the cable. To meet the connection space layout requirements, the cable does not need to be bent as a whole, but is achieved through the conductor bending design. The head and tail of the cable can be combined and connected with other connectors or components through the gold fingers, forming an interconnection architecture with better transmission performance and more flexible layout. Brief Description of the Drawings

[0024] Figure 1 is a schematic structural diagram of the prior art; Figure 2 is a schematic structural diagram of a differential pair; Figure 3 is Figure 2 A-A cross-sectional view of Figure 4 is Figure 2 an enlarged view of part I in Figure 5 is a schematic structural diagram of the conductor; Figure 6 is a first schematic structural diagram of a flat differential cable; Figure 7 is a second schematic structural diagram of a flat differential cable; Figure 8 is a third schematic structural diagram of a flat differential cable; Figure 9 is a fourth schematic structural diagram of a flat differential cable; Figure 10 is a cross-sectional view of the interconnection architecture; Figure 11 is a schematic diagram of the interconnection architecture; Figure 12 is a schematic diagram of the application of Example 1 of the interconnection architecture; Figure 13 is a schematic diagram of the application of Example 2 of the interconnection architecture; Figure 14 is a schematic diagram of the application of Example 3 of the interconnection architecture; In the figure: 1. Flat differential cable, 2. Gold finger; 11. Differential pair, 12. Insulating layer, 13. Shielding layer, 14. Air gap; 111. Conductor, 121. Upper insulating layer, 122. Lower insulating layer, 123. Adhesive layer, 131. Upper shielding layer, 132. Lower shielding layer. Detailed Implementation Manner

[0025] In order to make the objectives, technical solutions and advantages of the present application more clear and understandable, the present application will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0026] It should be noted that the illustrations provided in this embodiment only schematically illustrate the basic concept of the present invention. Therefore, only the components related to the present invention are shown in the drawings, rather than being drawn according to the number, shape and size of the components in actual implementation. The types, quantities and proportions of the components in actual implementation can be arbitrarily changed, and the component layout type may also be more complex.

[0027] The structures, proportions, sizes, etc. shown in the drawings of this specification are only used to cooperate with the content disclosed in the specification for those familiar with this technology to understand and read, and are not used to limit the conditions under which the present invention can be implemented. Therefore, they do not have technical substance. Any modification of the structure, change of the proportional relationship or adjustment of the size, without affecting the effects that the present invention can produce and the objectives that can be achieved, should still fall within the scope that can be covered by the technical content disclosed in the present invention.

[0028] The orientation or positional relationship indicated by terms such as "upper", "lower", "left", "right", "middle", "longitudinal", "transverse", "horizontal", "inner", "outer", "radial", "circumferential", etc. cited in this specification is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of the present invention.

[0029] As Figure 2 、 Figure 3 、 Figure 5 shown, a differential pair structure includes a pair of conductors 111 arranged side by side. The cross-sectional shapes and sizes of the conductors 111 are the same, and the same core wires will not introduce common-mode signals. The pair of conductors 111 are arbitrarily bent and arranged at equal intervals in the same plane along the length direction. This arrangement form saves space layout. The cable does not need to be bent as a whole, but the conductors are bent for layout, so that the relative positions of the conductors and the air gaps in the insulating layer are fixed, and the structure is stable and the layout is flexible.

[0030] The single-core conductor 111 is integrally formed, not formed by twisting multiple cores. The advantages are that it can transmit high-speed signals, is more convenient to form, is not affected by twisting deformation, and when the cross-section of the conductor 111 is polygonal, the position of the center line of the single-core conductor can be clearly defined during the formation of the external insulating layer, and the shape is stable and the consistency is higher.

[0031] The cross-section of the conductor 111 is axisymmetric, and the axisymmetric shape is convenient for forming, including a circle (a special polygon form), an isosceles triangle, an equilateral triangle, an isosceles trapezoid, a quadrilateral, a hexagon, an octagon, etc. For polygons with the number of sides ≤ 18, the perimeter is significantly increased (>1%) compared to a circle with the same cross-sectional area. As the number of sides increases, the perimeters of the two become closer and closer. For example, Figure 2 the rectangular conductor shown, Figure 6 the circular conductor shown, Figure 7 the regular hexagon conductor shown.

[0032] As Figure 6 , Figure 7 shown, a flat differential cable includes at least a pair of differential pairs 11 arranged in the same plane, an insulating layer 12, and a shielding layer 13. The differential pair 11 has the above-mentioned differential pair structure. The arrangement form of the differential pair 11 is in a "one" shape arrangement in the direction shown in the figure. The axes of the conductors of all differential pairs are in the same plane. The insulating layer 12 is coated on the outside of the differential pair 11 to fix the differential pair 11, so that an air gap 14 extending in the bending direction is formed between each pair of conductors 111. A shielding layer is provided outside the insulating layer 12. An air gap is filled between the conductors of each pair of differential pairs of the cable. The introduction of the air gap reduces the equivalent dielectric constant of the insulating material, thereby reducing the insertion loss of the cable. When the flat differential cable is used in multiple layers, it can utilize a smaller space. By setting differential pairs with different bending forms, it can connect devices or connectors at various positions. For the connection of components under the plane, the cable does not need to be bent, which will not affect the air gap. For bending at other positions, it can basically be bent along the cable plane, which will not have too much impact on the air gap and will not cause unstable transmission. Bending along the cable plane means that the entire plane can be bent in a swinging manner up and down, and bending in the left and right directions can be achieved by bending the conductors in the same plane.

[0033] As Figure 8 , Figure 9As shown, the insulating layer 12 can be integrally formed or formed by bonding with an adhesive layer. The insulating layer 12 is composed of an upper insulating layer 121 and a lower insulating layer 122. The upper insulating layer 121 and the lower insulating layer 122 are respectively disposed on the upper and lower sides of the differential pair 11. An adhesive layer 123 is adhered to the lower surface of the upper insulating layer 121 and / or the upper surface of the lower insulating layer 122. The upper insulating layer 121 and the lower insulating layer 122 are bonded together by the adhesive layer 123 to sandwich the differential pair 11. Adhesive layers are adhered to both the upper insulating layer 121 and the lower insulating layer 122. Alternatively, there is only one adhesive layer on either the upper insulating layer 121 or the lower insulating layer 122. The bonding of the upper and lower insulating layers is performed by hot pressing with a jig or an automated device. First, the differential pair is adhered, and the position of the differential pair is fixed to prevent rotation, so that the differential pair 11 in the upper insulating layer 121 and the lower insulating layer 122 is precisely maintained in a state of a fixed spacing and is pressed and adhered therein. Moreover, the dielectric constant of the adhesive layer is lower than that of the insulating layer 12, further reducing the equivalent dielectric constant between the differential pair and the insulating layer, reducing the dielectric loss, and thus reducing the cable insertion loss.

[0034] The shielding layer 13 includes an upper shielding layer 131 and a lower shielding layer 132 respectively located on the upper and lower sides of the insulating layer 12. The shielding layer 13 can be disposed on the surface of the insulating layer 12 in a pressing form for electromagnetic shielding. The shielding layer 13 is an aluminum foil layer or a copper foil layer. The shielding effect of the full shielding of the upper and lower layers is the best, and there is no need to shield the differential pair separately, and it can also achieve a sufficient shielding effect.

[0035] The shielding layer 13 can also be a single shielding layer disposed on the upper side or the lower side of the insulating layer 12, such as Figure 6 、 Figure 7 、 Figure 8 、 Figure 9 As shown, there is only the upper shielding layer 131 or the lower shielding layer 132, and the direction of single-sided shielding can be selected according to the electromagnetic influence at the location to reduce costs.

[0036] Such as Figure 8 、 Figure 9 As shown, the shielding layer 13 is bonded to the outside of the insulating layer 12 through the adhesive layer 123. The adhesive layer is used to fix the shielding layer 13, which can not only reduce the forming difficulty of the flat differential cable, but also reduce the dielectric constant of the outermost layer of the insulating layer and reduce the dielectric loss. The adhesive layer 123 for connecting the shielding layer 13 and the insulating layer 12 can be formed on the shielding layer 13 or on the outside of the insulating layer 12.

[0037] Such as Figure 10 As shown, an interconnection architecture includes the flat differential cable 1 described above, and the gold fingers 2 respectively connected to both ends of the flat differential cable 1. Such as Figure 11 As shown is an interconnection solution with a three-dimensional curved single-layer layout. By the curved conductor, the docking position is adjusted, and there is no need to bend the flat differential cable.

[0038] Aiming at the problems of large losses in existing PCB boards, difficult wiring of cable assemblies, and large space occupation, as shown in Figure 11 , 12 , Figures 13 and 14. The solution for interconnection using an interconnection architecture mainly consists of a flexible flat cable (FFC), a gold finger, a connector, etc. The cable is flat and contains multiple differential pairs, as well as an insulating layer and a shielding layer covering the conductors. An air gap is arranged between each pair of differential conductors. The introduction of the air gap reduces the equivalent dielectric constant of the insulating material, thereby reducing the insertion loss of the cable. To meet the requirements of the connection space layout, the cable does not need to be bent as a whole, but is realized through the conductor bending design. The head and tail of the flat differential cable 1 can be combined and connected with other connectors or components (wafer components, PCB boards, chips) through the gold finger 2, forming an interconnection architecture with better transmission performance and more flexible layout. As shown in the schematic diagram of PCB board interconnection in Figure 12 , the connection between each PCB board is realized through the black interconnection architecture. As shown in Figure 13 , the connection between the chip and the connector is realized through the interconnection of the yellow interconnection architecture and the blue interconnection architecture, and the connection between the connectors is realized through the blue interconnection architecture. As shown in Figure 14 , the interconnection architecture has two layers. The upper-layer interconnection architecture connects the wafer modules on both sides of the upper layer (Layer A), and the lower-layer interconnection architecture connects the wafer modules on both sides of the lower layer (Layer B). For the multi-layer layout interconnection solution, various interconnection architectures are reasonably bent and laid out to connect each component according to the space conditions, and can be installed in multiple layers stacked.

[0039] The above are only the preferred examples of the present invention and are not used to limit or define the present invention. For those skilled in the art, various changes and modifications can be made to the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope claimed by the present invention.

Claims

1. A differential pair structure, comprising a pair of conductors (111) arranged side by side, characterized in that: A pair of conductors (111) are arbitrarily bent in the same plane along the length direction and arranged at equal intervals.

2. The differential pair structure according to claim 1, characterized in that: The conductor (111) is a single-core conductor.

3. The differential pair structure according to claim 1, wherein: The cross-section of the conductor (111) is polygonal.

4. A differential pair structure as claimed in claim 1, wherein: The cross-section of the conductor (111) is an axisymmetric shape.

5. A flat differential cable, comprising at least a pair of differential pairs (11) arranged in the same plane, an insulating layer (12) and a shielding layer (13), characterized in that: The differential pair (11) is the differential pair structure according to any one of claims 1-4. The insulating layer (12) is coated on the outside of the differential pair (11) to fix the differential pair (11), so that an air gap (14) extending in the bending direction is formed between each pair of conductors (111). A shielding layer is provided on the outside of the insulating layer (12).

6. A flat differential cable as claimed in claim 5, wherein: The insulating layer (12) is composed of an upper insulating layer (121) and a lower insulating layer (122). The upper insulating layer (121) and the lower insulating layer (122) are respectively arranged on the upper and lower sides of the differential pair (11). An adhesive layer (123) is adhered to the lower surface of the upper insulating layer (121) and / or the upper surface of the lower insulating layer (122). The upper insulating layer (121) and the lower insulating layer (122) are adhered through the adhesive layer (123) to sandwich the differential pair (11).

7. The flat differential cable according to claim 5, characterized in that: The shielding layer (13) includes an upper shielding layer (131) and a lower shielding layer (132) respectively located on the upper and lower sides of the insulating layer (12).

8. The flat differential cable according to claim 5, characterized in that: The shielding layer (13) is a single shielding layer provided on the upper side or the lower side of the insulating layer (12).

9. A flat differential cable as claimed in claim 5, wherein: The shielding layer (13) is adhered to the outside of the insulating layer (12) through the adhesive layer (123).

10. An interconnection architecture, characterized in that: It includes a flat differential cable (1) according to any one of claims 5-9, and a gold finger (2) respectively connected to both ends of the flat differential cable (1).

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