Signal transmission cable

Abstract

To provide a signal transmission cable capable of restraining a deterioration of transmission characteristics and an increase of internal skews.SOLUTION: A signal transmission cable 1 includes: two aligned insulation core wires 3A, 3B; a coating layer 11 integrally coating the two aligned insulation core wires; and a protective layer 13 disposed on an outer periphery of the coating layer. Each of the insulation core wires includes: an internal conductor 5; an insulator 7 disposed on an outer periphery of the internal conductor; and a conductor layer 9 disposed on an outer periphery of the insulator. The conductor layer is, for instance, a plating layer. The signal transmission cable further includes, for instance, a metal layer 15 between the protective layer and the coating layer.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to a cable for signal transmission. [Background technology]

[0002] Patent Documents 1 and 2 disclose signal transmission cables. A conventional signal transmission cable is a twin-ax cable 101 shown in Fig. 4. The twin-ax cable 101 includes two insulated core wires 103A and 103B arranged side by side, a metal tape 115, and a jacket 113.

[0003] Each of the two insulated core wires 103A and 103B includes an inner conductor 105 and an insulator 107. The insulator 107 is provided on the outer periphery of the inner conductor 105. The two insulated core wires 103A and 103B are integrated together by a metal tape 115. A jacket 113 is provided on the outer periphery of the metal tape 115. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2002-358841 A [Patent Document 2] JP 2010-73463 A Summary of the Invention [Problem to be solved by the invention]

[0005] The twinax cable 101 transmits signals through the central conductor 105 and the metal tape 115. In the twinax cable 101, an air layer 121 exists between the central conductor 105 and the metal tape 115. The air layer 121 is an area occupied by air. Due to slackness of the metal tape 115, etc., an imbalance in size of the air layer 121 occurs inside the twinax cable 101. When an imbalance in size of the air layer 121 occurs, the transmission characteristics of the twinax cable 101 deteriorate.

[0006] Furthermore, one of the two insulated core wires 103A, 103B may move in the longitudinal direction relative to the other, increasing the in-pair skew of the twin-ax cable 101. In one aspect of the present disclosure, it is preferable to provide a signal transmission cable capable of suppressing deterioration of transmission characteristics and increase in intra-pair skew. [Means for solving the problem]

[0007] One aspect of the present disclosure is a signal transmission cable including two aligned insulated core wires, a coating layer collectively coating the two insulated core wires, and a protective layer provided on the outer periphery of the coating layer. Each of the two insulated core wires includes an inner conductor, an insulator provided on the outer periphery of the inner conductor, and a conductor layer provided on the outer periphery of the insulator.

[0008] A signal transmission cable according to one aspect of the present disclosure can suppress degradation of transmission characteristics and increase in intra-pair skew. [Brief description of the drawings]

[0009] [Figure 1] 1 is a cross-sectional view illustrating a configuration of a signal transmission cable according to a first embodiment. [Diagram 2] 6 is a cross-sectional view illustrating a configuration of a signal transmission cable according to a second embodiment. FIG. [Diagram 3] 1 is a cross-sectional view showing a configuration of a signal transmission cable having an air layer. [Figure 4] 1 is a cross-sectional view showing the configuration of a conventional twin-ax cable. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Exemplary embodiments of the present disclosure will now be described with reference to the drawings. First Embodiment 1. Structure of signal transmission cable 1 The configuration of signal transmission cable 1 will be described with reference to Fig. 1. Signal transmission cable 1 is a long linear member. Signal transmission cable 1 has the shape shown in Fig. 1 in any cross section (hereinafter referred to as a transverse cross section) perpendicular to the longitudinal direction of signal transmission cable 1.

[0011] The signal transmission cable 1 includes two insulated core wires 3A, 3B. Each of the two insulated core wires 3A, 3B is a linear member extending straight along the longitudinal direction of the signal transmission cable 1. The two insulated core wires 3A, 3B are arranged side by side. The two insulated core wires 3A, 3B are in contact with each other at their outer circumferential surfaces.

[0012] The insulated core wire 3A and the insulated core wire 3B have the same configuration. Here, the configuration of the insulated core wire 3A will be described. The insulated core wire 3A includes an inner conductor 5, an insulator 7, and a conductor layer 9. The inner conductor 5 is, for example, a linear member made of a metal. Examples of metals include copper, copper alloys, aluminum, and aluminum alloys. The shape of the inner conductor 5 in cross section is, for example, circular or elliptical. The inner conductor 5 is, for example, a plain wire or a stranded wire. The inner conductor 5 may be a plated wire. The inner conductor 5 transmits, for example, a signal.

[0013] The insulator 7 is provided on the outer periphery of the internal conductor 5. The insulator 7 covers the outer periphery of the internal conductor 5. The cross-sectional shape of the insulator 7 is, for example, circular or elliptical. Examples of the material for the insulator 7 include polyethylene, polypropylene, fluorine-based resin, and polyimide. The material for the insulator 7 is preferably a material with a low dielectric constant. The insulator 7 may be made of one layer or two or more layers.

[0014] The conductor layer 9 is provided on the outer periphery of the insulator 7. The conductor layer 9 covers the outer periphery of the insulator 7. The conductor layer 9 is made of, for example, a metal. Examples of the metal include copper, copper alloy, aluminum, and aluminum alloy. The thickness of the conductor layer 9 is, for example, 1 μm or more and 10 μm or less.

[0015] The conductor layer 9 is, for example, a plating layer. The conductor layer 9 may also be, for example, a sputtered layer, a vapor deposition layer, or the like. The conductor layer 9 may also be, for example, a metal tape attached to the outer circumferential surface of the insulator 7. The conductor layer 9 transmits, for example, a signal. The conductor layer 9 is grounded.

[0016] The signal transmission cable 1 includes a covering layer 11. The covering layer 11 covers the two insulated core wires 3A, 3B together. The covering layer 11 covers, for example, the entire outer circumferential surfaces of the two insulated core wires 3A, 3B. The material of the covering layer 11 is, for example, an insulator. Examples of the insulator include resin. Examples of the resin include polyethylene, polypropylene, fluorine-based resin, polyimide, polyurethane, etc. The shape of the covering layer 11 in cross section is, for example, an ellipse as shown in FIG. 1. The major axis direction of the ellipse is the direction in which the two insulated core wires 3A, 3B are arranged side by side. The covering layer 11 can be molded in one lump by, for example, extrusion.

[0017] The signal transmission cable 1 includes a protective layer 13. The protective layer 13 covers the outer peripheral surface of the covering layer 11. The protective layer 13 is, for example, a tape member. The tape member is wound around the outer peripheral surface of the covering layer 11. The tape member may be wound in a spiral manner or vertically. Examples of the material of the protective layer 13 include resins, etc. Examples of resins include polyester and polyimide. The signal transmission cable 1 is, for example, a differential signal transmission cable.

[0018] 2.Effects of Signal Transmission Cable 1 (1A) The space between the internal conductor 5 and the conductor layer 9 is filled with the insulator 7. Therefore, it is difficult for an air gap to exist between the internal conductor 5 and the conductor layer 9. As a result, it is possible to suppress a deterioration in transmission characteristics caused by an imbalance in the size of the air gap.

[0019] (1B) The covering layer 11 covers the two insulated core wires 3A and 3B together. This makes it possible to prevent one of the two insulated core wires 3A and 3B from moving in the longitudinal direction relative to the other. As a result, it is possible to prevent in-pair skew.

[0020] (1C) The covering layer 11 collectively covers the two insulated core wires 3A and 3B, which makes it easy to process the terminal of the signal transmission cable 1. (1D) The conductor layer 9 is, for example, a plating layer. When the conductor layer 9 is a plating layer, the adhesion between the conductor layer 9 and the insulator 7 is high. As a result, it is possible to suppress inter-mode skew. (1E) The covering layer 11 covers the entire outer circumferential surfaces of the two insulated core wires 3A, 3B at once. This further prevents one of the two insulated core wires 3A, 3B from moving in the longitudinal direction relative to the other. As a result, in-pair skew can be further suppressed. <Second embodiment> 1. Differences from the first embodiment The second embodiment has a basic configuration similar to that of the first embodiment, and therefore differences will be described below. Note that the same reference numerals as those in the first embodiment indicate the same configuration, and the preceding description will be referred to.

[0021] In the first embodiment described above, the protective layer 13 covers the outer peripheral surface of the covering layer 11. In contrast, in the second embodiment, as shown in FIG. 2, a metal layer 15 is further provided between the protective layer 13 and the covering layer 11. The metal layer 15 is, for example, a tape made of metal. The tape made of metal may be wound in a spiral shape or may be attached vertically. The metal constituting the metal layer 15 is not particularly limited, and examples thereof include copper, copper alloy, aluminum, aluminum alloy, and iron. The thickness of the metal layer 15 is, for example, 5 μm or more and 15 μm or less. The metal layer 15 is also grounded. 2, the covering layer 11 is interposed between the metal layer 15 and the conductor layer 9, but the metal layer 15 and the conductor layer 9 may be in direct contact with each other. In this case, the conductor layer 9 is grounded via the metal layer 15 by connecting the metal layer 15 to the ground.

[0022] 2.Effects of Signal Transmission Cable 1 According to the second embodiment described above in detail, in addition to the effects of the first embodiment described above, the following effects are also obtained.

[0023] (2A) The metal layer 15 has the effect of suppressing noise. <Other embodiments> Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the above-described embodiments and can be implemented in various modified forms.

[0024] (1) The signal transmission cable 1 of the first embodiment may have an air layer 21 as shown in FIG. 3. The air layer 21 exists near the contact 4 of the two insulated core wires 3A and 3B. The air layer 21 is a region surrounded by the outer circumferential surface of the insulated core wire 3A, the outer circumferential surface of the insulated core wire 3B, and the surface of the coating layer 11. The air layer 21 is filled with air. When the air layer 21 exists, one of the two insulated core wires 3A and 3B can move in the longitudinal direction relative to the other to an extent that does not excessively deteriorate the in-pair skew. This makes it easier to bend the signal transmission cable 1. The signal transmission cable 1 of the second embodiment may also have the air layer 21 shown in FIG. 3.

[0025] (2) The function of one component in each of the above embodiments may be shared by multiple components, or the functions of multiple components may be performed by one component. Also, part of the configuration of each of the above embodiments may be omitted. Also, at least part of the configuration of each of the above embodiments may be added to or substituted for the configuration of another of the above embodiments.

[0026] (3) In addition to the above-described signal transmission cable 1, the present disclosure can be realized in various forms, such as a system including the signal transmission cable 1 as a component, a method for manufacturing the signal transmission cable 1, and the like. [Explanation of symbols]

[0027] 1...signal transmission cable, 3A, 3B...insulated core wire, 4...contact, 5...inner conductor, 7...insulator, 9...conductor layer, 11...coating layer, 13...protective layer, 15...metal layer, 21...air layer

Claims

1. Two insulated core wires arranged side by side; a covering layer that covers the two insulated core wires together; A protective layer provided on the outer periphery of the coating layer; Equipped with The two insulated core wires each have An inner conductor; an insulator provided on an outer periphery of the internal conductor; A conductor layer provided on the outer periphery of the insulator; Equipped with Signal transmission cable.

2. 2. The signal transmission cable according to claim 1, The conductor layer is a plating layer. Signal transmission cable.

3. 3. The signal transmission cable according to claim 1, A metal layer is further provided between the protective layer and the coating layer. Signal transmission cable.

4. 3. The signal transmission cable according to claim 1, The coating layer collectively covers the entire outer circumferential surfaces of the two insulated core wires. Signal transmission cable.

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