Conductive strands for fabric-based items
Strands of material may be intertwined using weaving techniques, knitting techniques, non-woven or entanglement techniques, or braiding techniques. Fabric that is formed from the strands of material may be used in forming a fabric-based item. The fabric based item may include electrical components. The strands may include conductive strands that form signal paths. The signal paths can carry electrical signals associated with operation of the electrical components. Each strand may have an elongated core and a coating. Strands may also include intermediate layers between the cores and coatings. The cores, intermediate layers, and coatings may be formed from polymer without conductive filler, polymer with conductive filler, and/or metal. A polymer core may be provided with recesses to help retain subsequently deposited layers such as a metal coating layer. The recesses may be grooves that extend along the longitudinal axis of the core.
1. A conductive strand for carrying signals within a fabric, comprising:
an elongated polymer core with recesses;
a conductive layer on the elongated polymer core, wherein the conductive layer has first portions in the recesses and second portions that are interposed between the recesses and that are electrically connected to the first portions; and
an exterior insulating layer on the conductive layer.
2. The conductive strand defined in claim 1 , wherein the first portions of the conductive layer have a first thickness and the second portions of the conductive layer have a second thickness that is less than the first thickness.
3. The conductive strand defined in claim 1 , wherein the conductive layer comprises metal.
4. The conductive strand defined in claim 1 , wherein the recesses comprise grooves.
5. The conductive strand defined in claim 4 , wherein the elongated polymer core is elongated along a longitudinal axis and wherein the grooves run parallel to the longitudinal axis.
6. The conductive strand defined in claim 1 , wherein the recesses comprise a plurality of pits in an outer surface of the elongated polymer core.
7. The conductive strand defined in claim 1 , wherein each recess has a width and a depth that is between 0.1 and 1 times the width.
8. A conductive strand for carrying signals within a fabric, comprising:
an elongated conductive core;
an intermediate layer that covers the elongated conductive core, wherein the intermediate layer comprises a polymer layer with conductive filler; and
a conductive coating on the intermediate layer, wherein the conductive filler electrically connects the conductive coating to the conductive core.
9. The conductive strand defined in claim 8 , wherein the conductive core is formed from metal.
10. The conductive strand defined in claim 8 , wherein the conductive coating is a metal coating.
11. The conductive strand defined in claim 8 , wherein the conductive filler comprises metal particles.
12. The conductive strand defined in claim 8 , wherein the conductive filler comprises carbon nanotube material.
13. The conductive strand defined in claim 8 , wherein the conductive filler comprises graphene particles.
14. The conductive strand defined in claim 8 , wherein the conductive filler comprises fibrous carbon material.
15. The conductive strand defined in claim 8 , wherein the intermediate layer has a plurality of recesses and wherein the conductive coating is formed in the recesses.
16. The conductive strand defined in claim 15 , wherein the conductive coating has first portions in the recesses and second portions that are interposed between the recesses, wherein the first portions of the conductive coating have a first thickness, and wherein the second portions of the conductive coating have a second thickness that is less than the first thickness.
17. A multi-filament strand for carrying signals within a fabric, the multi-filament strand comprising:
a core strand;
a plurality of strands wrapped around the core strand; and
a coating formed over the plurality of strands.
18. The multi-filament strand defined in claim 17 , wherein the coating is a conductive coating.
19. The multi-filament strand defined in claim 17 , wherein the plurality of strands comprises a plurality of conductive strands.
20. The multi-filament strand defined in claim 17 , wherein the core strand is a polymer core strand.