Differential signal transmission cable

Patent metadata

Field	Value
Publication number	US-12250802-B2
Application number	US-202017792492-A
Country	US
Kind code	B2
Filing date	Jan 30, 2020
Priority date	Jan 30, 2020
Publication date	Mar 11, 2025
Grant date	Mar 11, 2025

Abstract

A differential signal transmission cable includes an insulation layer extending in a longitudinal direction of the differential signal transmission cable, a pair of signal lines extending in the longitudinal direction and buried inside the insulation layer, an intermediate layer covering an outer circumferential surface of the insulation layer, a shield, and catalyst particles. The shield includes an electroless plating layer covering an outer circumferential surface of the intermediate layer. The catalyst particles are dispersed between the intermediate layer and the electroless plating layer.

First claim

The invention claimed is:

1. A differential signal transmission cable comprising:
an insulation layer extending in a longitudinal direction of the differential signal transmission cable;
a pair of signal lines extending in the longitudinal direction and buried inside the insulation layer;
an intermediate layer covering an outer circumferential surface of the insulation layer;
a shield covering an outer circumferential surface of the intermediate layer; and
catalyst particles,
wherein
the shield includes an electroless plating layer covering the outer circumferential surface of the intermediate layer, and
the catalyst particles are dispersed between the intermediate layer and the electroless plating layer such that the catalyst particles are not in the form of a layer, and an area of the outer circumferential surface of the intermediate layer in which catalyst particles are not placed is not less than 90% of the area of the entire outer circumferential surface of the intermediate layer.

2. The differential signal transmission cable according to claim 1 , wherein an amount of the catalyst particles contained in the differential signal transmission cable is not less than 0.1 μg and not greater than 10 μg per centimeter in the longitudinal direction.

3. The differential signal transmission cable according to claim 1 , wherein an arithmetic average roughness on the outer circumferential surface of the insulation layer is not greater than 2.0 μm.

4. The differential signal transmission cable according to claim 1 , wherein an arithmetic average roughness on the outer circumferential surface of the insulation layer is less than 0.6 μm.

5. The differential signal transmission cable according to claim 1 , wherein a bonding strength between the intermediate layer and the electroless plating layer is not less than 0.1 N/cm and not greater than 6 N/cm.

6. The differential signal transmission cable according to claim 1 , wherein a thickness of the electroless plating layer is not less than 0.05 μm and not greater than 0.5 μm.

7. The differential signal transmission cable according to claim 1 , wherein the shield further includes an electroplating layer covering an outer circumferential surface of the electroless plating layer.

8. The differential signal transmission cable according to claim 7 , wherein
the electroplating layer is a copper electroplating layer, and
an average grain size of copper grains of the electroplating layer is not less than 0.5 μm.

9. The differential signal transmission cable according to claim 7 , wherein a sum of a thickness of the electroless plating layer and a thickness of the electroplating layer is not greater than 6 μm.

10. The differential signal transmission cable according to claim 1 , wherein the catalyst particles contain palladium.

11. The differential signal transmission cable according to claim 1 , wherein the insulation layer includes polyolefin having a melting point of not less than 140° C.

12. The differential signal transmission cable according to claim 1 , wherein the insulation layer includes at least any of polypropylene, cyclic olefin polymer, and polymethylpentene.

13. The differential signal transmission cable according to claim 1 , wherein
the insulation layer includes polypropylene grains, and
the polypropylene grains have a crystallinity X c of not less than 0.3, the crystallinity X c being calculated by an equation (1),

X
c

=

I
c

I
c

+

I
a

(
1
)

where I c denotes an X-ray diffraction intensity of a crystalline component, and I a denotes an X-ray diffraction intensity of a non-crystalline component.

14. The differential signal transmission cable according to claim 1 , wherein
the insulation layer includes polypropylene grains,
the polypropylene grains have a crystal structure of monoclinic crystal, a crystal structure of hexagonal crystal, or a coexisting state of at least one of these crystal structures, and the polypropylene grains are oriented along two or less specific crystallographic axes, and
in the insulation layer, a degree of crystalline orientation O 110 calculated by an equation (2) is not greater than 0.65,

O
110

=

I
110

I
110

+

I
040

(
2
)

where I 110 denotes an integrated intensity of X-ray diffraction with an index 110, and I 040 denotes an integrated intensity of X-ray diffraction with an index 040.

15. A differential signal transmission cable comprising:
an insulation layer extending in a longitudinal direction of the differential signal transmission cable;
a pair of signal lines extending in the longitudinal direction and buried inside the insulation layer;
an intermediate layer covering an outer circumferential surface of the insulation layer;
a shield covering an outer circumferential surface of the intermediate layer; and
catalyst particles,
wherein
the shield includes an electroless plating layer covering the outer circumferential surface of the intermediate layer,
the catalyst particles are dispersed between the intermediate layer and the electroless plating layer such that the catalyst particles are not in the form of a layer, and an area of the outer circumferential surface of the intermediate layer in which catalyst particles are not placed is not less than 90% of the area of the entire outer circumferential surface of the intermediate layer, and
a thickness of the intermediate layer is not greater than 1 μm.

Assignees

• Sumitomo Electric Industries

Inventors

• Goto Kengo
• Hosoe Akihisa
• KOBAYASHI Yuto
• Ochi Yuji

Classifications

• H05K9/0088

  comprising a plurality of shielding layers; combining different shielding material structure · CPC title

• H01B13/222

  by electro-plating · CPC title

• H01B11/002

  Pair constructions · CPC title

• H01B3/441 Primary

  from alkenes · CPC title

• H01B7/18

  Protection against damage caused} by wear, mechanical force or pressure; {Sheaths; Armouring · CPC title