A data transmission cable with multiple groups of differential signal transmission units sharing a common ground

Abstract

The present invention discloses a data transmission cable with multiple groups of differential signal transmission units sharing a common ground, comprising: a plurality of groups of differential signal transmission units and a plurality of ground wires arranged according to a set combination and bonded by transparent insulating hot-melt Mylar and single-sided conductive aluminum foil Mylar; the differential signal transmission unit comprises a hot-melt copper foil Mylar and a pair of differential signal wires wrapped by the hot-melt copper foil Mylar; the outer side of the hot-melt copper foil Mylar is a conductive side bonded to the conductive side of the single-sided conductive aluminum foil Mylar; the ground wire is connected by bonding to the conductive side of the single-sided conductive aluminum foil Mylar. The data transmission cable with multiple groups of differential signal transmission units sharing a common ground provided by the present invention avoids the disadvantage of characteristic impedance change caused by two metal foils not being able to bond tightly together, improves the bandwidth of data transmission, reduces insertion loss and has a higher density at the same time.

Description

Technical Field

[0001] The present invention relates to the technical field of data transmission cables, and in particular to a data transmission cable with a plurality of groups of differential signal transmission units sharing a common ground. Background Art

[0002] At present, there are mainly three types of common data transmission cables: the first type is to wrap a group of differential signal transmission units by laminating two pieces of aluminum foil Mylar on the upper and lower sides, and the aluminum foil Mylar is used as a reference layer to connect the ground wire to the ground; the second type is to wrap a group of differential signal conductors together with the ground wire through aluminum foil Mylar as a group of differential signal transmission units, and the ground wire is on one side of the center line connecting the two conductors and is no longer on the same plane; the third type is to wrap a group of differential signal conductors together with two ground wires through aluminum foil Mylar as a group of differential signal transmission units, and the ground wire is on the left and right sides of the center line connecting the two conductors and is on the same plane;

[0003] However, all three solutions have their own shortcomings. In Solution 1, the two aluminum foil Mylars are attached together and close to the left and right places of the insulation, which cannot fit tightly, resulting in changes in the impedance at that location, affecting the integrity of signal transmission; in Solution 2, after peeling off the aluminum foil and insulation, the position of the ground wire must be manually adjusted before it can be welded to the pad, and a ground wire grounding pad must be assigned to each pair to make it work normally, affecting production efficiency and quality; in Solution 3: the total width of the cable is too large and the density is low; the processing efficiency is low during welding; the ground wire and the transmission unit in the same plane are wrapped, the structure is unstable, and it is easy to twist and deform, which affects the consistency and causes changes in the characteristic impedance, thereby affecting the integrity of signal transmission. Summary of the invention

[0004] In view of the problems existing in the prior art, the present invention provides a data transmission cable with a plurality of groups of differential signal transmission units sharing a common ground, thereby avoiding the disadvantage of characteristic impedance change caused by two metal foils not being able to fit tightly together, improving the bandwidth of data transmission, reducing insertion loss and having a higher density at the same time.

[0005] To achieve the above object, the present invention provides a data transmission cable with a plurality of groups of differential signal transmission units sharing a common ground, comprising:

[0006] Arrange according to the set combination, and use a number of groups of differential signal transmission units and a number of ground wires bonded by transparent insulating hot-melt Mylar and single-sided conductive aluminum foil Mylar;

[0007] The differential signal transmission unit comprises a hot-melt copper foil Mylar and a pair of differential signal lines wrapped by the hot-melt copper foil Mylar;

[0008] The outer side of the hot-melt copper foil Mylar is a conductive side, which is bonded to the conductive side of the single-sided conductive aluminum foil Mylar; the ground wire is connected by bonding to the conductive side of the single-sided conductive aluminum foil Mylar.

[0009] Preferably, the insulating side material of the single-sided conductive aluminum foil Mylar is insulating plastic Mylar, and the conductive side material is aluminum-based conductive metal foil.

[0010] Preferably, the outer side of the hot-melt copper foil Mylar is a conductive side, which is bonded to the conductive side of the single-sided conductive aluminum foil Mylar, including:

[0011] The conductive side of the hot-melt copper foil Mylar is directly bonded to the conductive side of the single-sided conductive aluminum foil Mylar, or is bonded by conductive hot-melt adhesive.

[0012] Preferably, the ground wire is connected by laminating with the conductive side of the single-sided conductive aluminum foil Mylar, including:

[0013] The ground wire is connected to the conductive side of the single-sided conductive aluminum foil Mylar by direct bonding or by conductive hot melt adhesive bonding.

[0014] Preferably, the pair of differential signal lines wrapped by the hot-melt copper foil Mylar is specifically: the hot-melt copper foil Mylar wraps the pair of differential signal lines by hot-melt method.

[0015] Preferably, the transparent insulating hot-melt Mylar is made of polyester resin.

[0016] Preferably, the differential signal line comprises a conductor and an insulating layer wrapped around the outside of the conductor, and the material of the insulating layer is any one of polyethylene, polypropylene, polytetrafluoroethylene and poly(perfluoroethylene-propylene) copolymer.

[0017] Preferably, the material of the conductor and the ground wire is any one of silver-plated copper, tin-plated copper and bare copper.

[0018] Preferably, the sizes of the conductor and the ground wire are any one of 22 American Wire Gauge to 36 American Wire Gauge.

[0019] Compared with the prior art, the high-speed data transmission cable with multiple groups of differential signal transmission units sharing a common ground provided by the embodiment of the present invention has at least the following beneficial effects:

[0020] 1) The method of integrally forming two conductors of each differential signal transmission unit improves the accuracy of the relative position of the two conductors; the design of the relative position of the two conductors is more flexible; in subsequent production tests, as well as twisting and bending during use, the design structure can be better maintained without causing changes in electrical performance parameters;

[0021] 2) Each group of differential signal transmission units is independently shielded, which avoids the disadvantage of the characteristic impedance change caused by the gap between two metal foils being opened, thereby improving the bandwidth of data transmission;

[0022] 3) The ground wire in the unit is removed and connected to the ground wire through aluminum foil, making the structure in the unit simpler and more compact, reducing the total width when multiple thick arrangements are made; at the same time, it is easier to strip and weld the wires during the subsequent production of cable assemblies, improving production efficiency and quality;

[0023] 4) The outermost layer of one side is made of single-sided aluminum foil, which reduces the cost, reduces the thickness of the cable, and makes the cable softer;

[0024] 5) The difference in appearance of the two outermost layers of film makes it easier to identify the direction during subsequent assembly and to trace the order of each unit group in the cable when bending and wiring. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a cross-sectional schematic diagram of a data transmission cable with a group of differential signal transmission units sharing a common ground provided by an embodiment of the present invention;

[0026] Figure 2 It is a structural schematic diagram of a data transmission cable with a plurality of groups of differential signal transmission units sharing a common ground provided by an embodiment of the present invention;

[0027] Figure 3 is a cross-sectional schematic diagram of a data transmission cable with a plurality of groups of differential signal transmission units sharing a common ground provided by an embodiment of the present invention;

[0028] Figure 4 is a cross-sectional schematic diagram of a data transmission cable with a plurality of groups of differential signal transmission units sharing a common ground provided by an embodiment of the present invention;

[0029] Figure 5 is a cross-sectional schematic diagram of a data transmission cable with a plurality of groups of differential signal transmission units sharing a common ground provided by an embodiment of the present invention;

[0030] Figure 6 is a cross-sectional schematic diagram of a data transmission cable with a plurality of groups of differential signal transmission units sharing a common ground provided by an embodiment of the present invention;

[0031] Figure 7 It is a cross-sectional schematic diagram of a data transmission cable with a plurality of groups of differential signal transmission units sharing a common ground provided by an embodiment of the present invention.

[0032] Description of main components and symbols:

[0033] Data transmission cable 100, ground wire 10, hot-melt copper foil Mylar 20, differential signal line 30, conductor 301, insulating layer 302, transparent insulating hot-melt Mylar 40, single-sided conductive aluminum foil Mylar 50, differential signal transmission unit 60 DETAILED DESCRIPTION

[0034] The specific embodiments of the present invention are further described in detail below in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in the field without creative work belong to the scope of protection of the present invention.

[0035] See also Figure 1 According to an embodiment of the present invention, a data transmission cable having a plurality of groups of differential signal transmission units sharing a common ground is provided, comprising:

[0036] Arrange according to the set combination, and use a number of groups of differential signal transmission units and a number of ground wires bonded by transparent insulating hot-melt Mylar and single-sided conductive aluminum foil Mylar;

[0037] The differential signal transmission unit comprises a hot-melt copper foil Mylar and a pair of differential signal lines wrapped by the hot-melt copper foil Mylar;

[0038] The outer side of the hot-melt copper foil Mylar is a conductive side, which is bonded to the conductive side of the single-sided conductive aluminum foil Mylar; the ground wire is connected by bonding to the conductive side of the single-sided conductive aluminum foil Mylar.

[0039] In this embodiment, it should be noted that a differential signal transmission unit is composed of a hot-melt copper foil Mylar and a pair of differential signal lines wrapped by the hot-melt copper foil Mylar, wherein the hot-melt copper foil Mylar is also called copper foil Mylar polyester tape, which has a golden appearance, uniform color, and is odorless. It utilizes the high tensile strength and electrical properties of the biaxially oriented polyester material to provide insulation for the internal structure of the cable, and is suitable for insulation purposes of composite wires with multi-strand structures such as signal transmission lines and control lines, and other wires. In this embodiment, the ground wire and the differential signal transmission unit are arranged in a certain combination and then bonded together by transparent insulating hot-melt Mylar and single-sided conductive aluminum foil Mylar. The copper foil layer serves as the reference surface of the differential signal line, and is electrically connected to the single-sided conductive aluminum foil Mylar, and the ground wire is also electrically connected to the single-sided conductive aluminum foil Mylar, thereby realizing the grounding of the reference surface of the differential signal unit. In addition, the outermost layer on one side is made of single-sided aluminum foil, which reduces the cost and thickness of the cable, making it softer; the outermost layer on the other side is made of transparent hot-melt Mylar, so that the true color of the copper foil Mylar can be seen from the outside, making the appearance better and more technological. And because the appearance of the two outermost layers of film is different, it is convenient to identify the direction during subsequent assembly, and it is easy to trace the order of each unit group in the cable when bending and wiring.

[0040] In a certain embodiment of the present invention, the insulating side material of the single-sided conductive aluminum foil Mylar is insulating plastic Mylar, and the conductive side material is aluminum-based conductive metal foil.

[0041] In this embodiment, the single-sided conductive aluminum foil has single-sided conductivity, and the conductive side material is aluminum-based conductive metal foil, which is a thin, continuous metal foil, usually used as a conductor of a circuit board, and has good ductility; the insulating plastic Mylar is a Mylar sheet, and the Mylar sheet has a variety of color classifications such as milky white, black, natural color, and transparent color. Mylar sheets are divided into various materials, such as PET Mylar sheets, PVC Mylar sheets, PC Mylar sheets, and fireproof Mylar sheets. Common applications are divided into: insulating type, buffer type, wear-resistant type, sealing type, and appearance decorative type Mylar, and insulating plastic Mylar is used here.

[0042] In one embodiment of the present invention, the outer side of the hot-melt copper foil Mylar is a conductive side, which is bonded to the conductive side of the single-sided conductive aluminum foil Mylar, including:

[0043] The conductive side of the hot-melt copper foil Mylar is directly bonded to the conductive side of the single-sided conductive aluminum foil Mylar, or is bonded by conductive hot-melt adhesive.

[0044] In this embodiment, the hot melt copper foil Mylar is a single-sided conductive Mylar, and its conductive side is directly bonded to the conductive side of the single-sided conductive aluminum foil Mylar, or bonded through conductive hot melt adhesive. The hot melt adhesive has the characteristics of no odor and high melting point, so it is excellent in environmental protection and washing resistance. At the same time, the hot melt adhesive mesh has good air permeability, and the products with high air permeability requirements can use the hot melt adhesive mesh as the raw material. The use of hot melt adhesive bonding has the following advantages: 1) fast bonding speed, convenient for continuous, automatic high-speed operation, low cost; 2) no solvent pollution, no combustion; 3) no drying process is required, and the bonding process is simple; 4) the product itself is solid, easy to pack, transport, and store, small footprint, and convenient to store; 5) has good bonding strength and flexibility; 6) can bond a wide range of objects, that is, bonding and sealing; 6) good gloss and gloss retention, good shielding. Of course, the use of hot melt adhesive bonding also has corresponding disadvantages, such as: limited performance, insufficient heat resistance, low bonding strength, poor chemical resistance; the need to be equipped with special hot melt equipment for construction, such as hot melt glue machines and hot melt glue guns; the bonding will be affected by the climate and seasons, etc. Therefore, in order to avoid this disadvantage, direct bonding can be used.

[0045] In one embodiment of the present invention, the ground wire is connected by laminating with the conductive side of the single-sided conductive aluminum foil Mylar, including:

[0046] The ground wire is connected to the conductive side of the single-sided conductive aluminum foil Mylar by direct bonding or by conductive hot melt adhesive bonding.

[0047] In a certain embodiment of the present invention, the pair of differential signal lines wrapped by the hot-melt copper foil Mylar is specifically: the hot-melt copper foil Mylar wraps the pair of differential signal lines by hot-melt method.

[0048] In a certain embodiment of the present invention, the transparent insulating hot-melt Mylar is made of polyester resin, which has the following characteristics: good mechanical properties, impact strength is 3-5 times that of other films, good folding resistance, oil resistance, fat resistance, olefin acid resistance, dilute alkali resistance, and resistance to most solvents; excellent high and low temperature resistance, can be used for a long time in the temperature range of 120°C, can withstand high temperatures of 150°C for short-term use, can withstand low temperatures of -70°C, and has little effect on its mechanical properties at high and low temperatures; low gas and water vapor permeability, excellent gas, water, oil and odor resistance; high transparency, can block ultraviolet rays, good gloss; non-toxic, tasteless, hygienic and safe, and can be directly used for food packaging. Polyester resin is the most important variety of thermoplastic polyester.

[0049] In one embodiment of the present invention, the differential signal line includes a conductor and an insulating layer wrapped around the outside of the conductor, and the material of the insulating layer is any one of polyethylene, polypropylene, polytetrafluoroethylene and polytetrafluoroethylene copolymer.

[0050] In this embodiment, it should be pointed out that the most commonly used in practical applications is polyperfluoroethylene propylene copolymer; also known as FEP, which can be applied to soft plastics. Its tensile strength, wear resistance and creep resistance are lower than many engineering plastics. It is chemically inert and has a low dielectric constant over a wide temperature and frequency range. The material does not ignite and can prevent the spread of flames. It has excellent wear resistance and a low friction coefficient. The material can be made into granular products for extrusion and molding, used as a powder for fluidized beds and electrostatic coating, and can also be made into aqueous dispersions. Semi-finished products include membrane plates. Its main uses are for making linings for pipes and chemical equipment, surface layers of drums, and various wires and cables, such as aircraft hook lines, booster cables, alarm cables, flat cables, and oil well logging cables. FEP film is also often used as a thin coating for solar collectors; polytetrafluoroethylene is transparent to opaque, easy to bend and elastic; while polyethylene is translucent to transparent, hard, and can be made into a transparent film; from the characteristics, polytetrafluoroethylene can be widely used in various places that need to resist acids, alkalis and organic solvents. It itself is not toxic to the human body, but one of the raw materials used in the production process, PFOA, is considered to be carcinogenic. It can work for a long time at a temperature of +250℃ to -180℃, and can withstand all chemicals except molten metal sodium and liquid fluorine. Its high temperature resistance and low friction coefficient not only play a lubricating role, but also become an ideal coating for non-stick pans and water pipe inner layers. Polyethylene is a thermoplastic resin obtained by polymerization of ethylene. It has excellent low temperature resistance (the lowest operating temperature can reach -70℃ to -100℃), good chemical stability, and can withstand the erosion of various acids and alkalis (except acids with oxidizing properties). It is insoluble in general solvents at room temperature, has low water absorption, and has excellent electrical insulation properties. However, polyethylene is very sensitive to environmental stress (chemical and mechanical effects), has poor heat aging resistance, and the properties of polyethylene vary from variety to variety, mainly depending on the molecular structure and density.

[0051] In one embodiment of the present invention, the conductor and the ground wire are made of any one of silver-plated copper, tin-plated copper and bare copper. Copper will oxidize in the air to produce verdigris, which will greatly reduce the electrical conductivity of the cable. Therefore, some manufacturers use tin-plated, nickel-plated or high-end silver-plated copper wire to make cables. Tin-plated copper wire has better electrical conductivity than bare copper. Of course, the cost is also higher than that of bare copper. In addition, for some projects that require welding, tin-plated copper is more convenient to weld. Therefore, tin-plated copper is commonly used as a conductor.

[0052] In one embodiment of the present invention, the conductor and the ground wire are made of any one of silver-plated copper, tin-plated copper and bare copper. Copper will oxidize in the air to produce verdigris, which will greatly reduce the electrical conductivity of the cable. Therefore, some manufacturers use tin-plated, nickel-plated or high-end silver-plated copper wire to make cables. Tin-plated copper wire has better electrical conductivity than bare copper. Of course, the cost is also higher than that of bare copper. In addition, for some projects that require welding, tin-plated copper is more convenient to weld. Therefore, tin-plated copper is commonly used as a conductor.

[0053] In a certain embodiment of the present invention, the size of the conductor and the ground wire is any one of 22 American Wire Gauge to 36 American Wire Gauge, abbreviated as AWG in English, which is a standard for distinguishing wire diameters and is also called Brown & Sharpe wire gauge. The value in front of AWG (such as 24AWG, 26AWG) indicates the number of holes that the wire must pass through before forming the final diameter. The larger the value, the higher the level of the holes through which the wire passes, and the smaller the diameter of the wire. Thick wires have better physical strength and lower resistance, but the thicker the wire, the more copper is required to make the cable, which will make the cable heavier, more difficult to install, and more expensive. The challenge of cable design is to use wires with the smallest possible diameter (reducing costs and installation complexity) while ensuring the maximum capacity of the wire at the necessary voltage and frequency.

[0054] See also Figure 2 and Figure 3 In one embodiment of the present invention, a data transmission cable having a plurality of differential signal transmission units sharing a common ground is provided. Figure 2 The overall structure diagram of the cable is shown below. Figure 3 is a cross-sectional view of the cable; the cable consists of 12 groups of differential signal transmission units and 4 ground wires, which are arranged in an overall cycle with 1 ground wire and 4 groups of differential signal transmission units, and finally the ground wire is connected at the tail side of the differential signal transmission unit.

[0055] See also Figure 4 and Figure 5 In one embodiment of the present invention, a cross-sectional view of a data transmission cable with multiple groups of differential signal transmission units sharing a common ground is provided. The cable is composed of 12 groups of differential signal transmission units and 6 ground wires, the middle of which can be conveniently cut open and then divided into two for application. The cross-sectional view of the cable after being divided into two is shown in FIG. Figure 5 shown.

[0056] See also Figure 6 In one embodiment of the present invention, a cross-sectional view of a data transmission cable with a plurality of groups of differential signal transmission units sharing a common ground is provided, wherein the cable is composed of 12 groups of differential signal transmission units and 7 ground wires.

[0057] See also Figure 7In one embodiment of the present invention, a cross-sectional view of a data transmission cable with a plurality of groups of differential signal transmission units sharing a common ground is provided, wherein the cable is composed of six groups of differential signal transmission units and four ground wires.

[0058] It should be noted that in actual applications, several groups of differential signal transmission units and several ground wires are bonded by transparent insulating hot-melt Mylar and single-sided conductive aluminum foil Mylar; the rules for arranging the combinations can be set according to specific needs. The above disclosure is only a preferred embodiment of the present invention, and of course it cannot be used to limit the scope of rights of the present invention. Ordinary technicians in this field can understand that all or part of the processes of the above embodiments and equivalent changes made according to the claims of the present invention still fall within the scope of the invention.

Claims

1. A data transmission cable with multiple groups of differential signal transmission units sharing a common ground, characterized in that: include: Arrange according to the set combination, and use a number of groups of differential signal transmission units and a number of ground wires bonded by transparent insulating hot-melt Mylar and single-sided conductive aluminum foil Mylar; The differential signal transmission unit comprises a hot-melt copper foil Mylar and a pair of differential signal lines wrapped by the hot-melt copper foil Mylar; The outer side of the hot-melt copper foil Mylar is the conductive side, which is bonded to the conductive side of the single-sided conductive aluminum foil Mylar; the ground wire is connected by bonding to the conductive side of the single-sided conductive aluminum foil Mylar; The insulating side material of the single-sided conductive aluminum foil Mylar is insulating plastic Mylar, and the conductive side material is aluminum-based conductive metal foil; The outer side of the hot-melt copper foil Mylar is a conductive side, which is bonded to the conductive side of the single-sided conductive aluminum foil Mylar, including: The conductive side of the hot-melt copper foil Mylar is directly bonded to the conductive side of the single-sided conductive aluminum foil Mylar, or is bonded by conductive hot-melt adhesive.

2. The data transmission cable with multiple groups of differential signal transmission units sharing a common ground according to claim 1, characterized in that: The ground wire is connected by laminating with the conductive side of the single-sided conductive aluminum foil Mylar, including: The ground wire is connected to the conductive side of the single-sided conductive aluminum foil Mylar by direct bonding or by conductive hot melt adhesive bonding.

3. The data transmission cable with multiple groups of differential signal transmission units sharing a common ground according to claim 1, characterized in that: The pair of differential signal lines wrapped by the hot-melt copper foil Mylar specifically includes: the hot-melt copper foil Mylar wraps the pair of differential signal lines by hot-melt method.

4. The data transmission cable with multiple groups of differential signal transmission units sharing a common ground according to claim 1, characterized in that: The material of the transparent insulating hot-melt Mylar is polyester resin.

5. The data transmission cable with multiple groups of differential signal transmission units sharing a common ground according to claim 1, characterized in that: The differential signal line comprises a conductor and an insulating layer wrapped around the outside of the conductor, and the material of the insulating layer is any one of polyethylene, polypropylene, polytetrafluoroethylene and polyperfluoroethylene-propylene copolymer.

6. The data transmission cable with multiple groups of differential signal transmission units sharing a common ground according to claim 5, characterized in that: The material of the conductor and the ground wire is any one of silver-plated copper, tin-plated copper and bare copper.

7. The data transmission cable with multiple groups of differential signal transmission units sharing a common ground according to claim 5, characterized in that: The sizes of the conductor and the ground wire are any one of 22 American wire gauge to 36 American wire gauge.

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