FABRIC AND YARN STRUCTURES FOR IMPROVING SIGNAL INTEGRITY IN FABRIC-BASED ELECTRICAL CIRCUITS

• US 20080287022A1
• Filed: 03/24/2008
• Published: 11/20/2008
• Est. Priority Date: 06/28/2002
• Status: Abandoned Application

• Current Assignee: North Carolina State University (University of North Carolina System)
• Original Assignee: North Carolina State University (University of North Carolina System)
• Inventors: Ghosh, Tushar K., Dhawan, Anuj, Muth, John, Seyam, Abdelfattah M.
• Application Number:
  US12/053,889
• Publication Number:
  US 20080287022A1
• Time in Patent Office: Days
• US Class Current: 442/229
• CPC Class Codes: D02G 3/38 Threads in which fibres, filaments, or yarns are wound with other yarns or filaments, e.g. wrap yarns, i.e. strands of filaments or staple fibres are wrapped by a helically wound binder yarn; D02G3/32 takes precedence; covering endless core threads with fibres by using open-end spinning techniques D01H4/00
• CPC Class Codes: D02G 3/441 Yarns or threads with antistatic, conductive or radiation-shielding properties electroconductive, anti-static or radiation-shielding filaments D01F1/09, D01F1/106; anti-static fabrics D03D15/533; conducting, insulating or anti-static layers for floor coverings D06N7/0042
• CPC Class Codes: H05K 2201/029 Woven fibrous reinforcement or textile
• CPC Class Codes: H05K 2201/09809 Coaxial layout
• CPC Class Codes: H05K 3/10 in which conductive material is applied to the insulating support in such a manner as to form the desired conductive pattern
• CPC Class Codes: Y10T 442/105 Comprising a composite fiber
• CPC Class Codes: Y10T 442/109 Metal or metal-coated fiber-containing scrim
• CPC Class Codes: Y10T 442/3065 Including strand which is of specific structural definition
• CPC Class Codes: Y10T 442/3382 Including a free metal or alloy constituent
• CPC Class Codes: Y10T 442/339 Metal or metal-coated strand
• CPC Class Codes: Y10T 442/3976 Including strand which is stated to have specific attributes [e.g., heat or fire resistance, chemical or solvent resistance, high absorption for aqueous composition, water solubility, heat shrinkability, etc.]
• CPC Class Codes: Y10T 442/655 Metal or metal-coated strand or fiber material

Abstract

Coaxial and twisted pair conductive yarn structures reduce signal crosstalk between adjacent lines in woven electrical networks. A coaxial conductive yarn structure includes an inner conductive yarn having a plurality of conductive strands twisted together. An outer conductive yarn is wrapped around the inner conductive yarn. An insulating layer separates the inner and outer yarns. A twisted pair conductive yarn structure includes first and second conductive yarns, each including a plurality of conductive strands being twisted together. The first and second conductive yarns are twisted together to form a helical structure. In a woven electrical network, at least one conductor of adjacent conductive yarn structures is connected to ground to reduce signal crosstalk. Coaxial and twisted pair yarn structures may also be formed simultaneously with weaving or knitting the threads that make up the structures into a fabric.

Claims

1. A twisted pair conductive yarn structure comprising:

(a) a first conductive yarn having a plurality of conductive strands being twisted together;

(b) a second conductive yarn having a plurality of conductive strands being twisted together, the second conductive yarn being twisted together with the first conductive yarn to form a helical structure; and

(c) at least one insulating layer surrounding at least one of the conductive yarns for electrically isolating the first and second conductive yarns from each other.

2. The twisted pair conductive yarn structure of claim 1 wherein the conductive strands comprise a conductive material selected from a group including metals, alloys, and conductive polymers.

3. The twisted pair conductive yarn structure of claim 1 wherein the insulating layer comprises an electrically insulating material selected from a group including polyvinylchloride;

rubber;

rubber forming polymers, including polyisoprene, polybutadiene, polychloroprene, and polyisobutylene;

polyesters;

polyolefins; and

polyamides.

4. The twisted pair conductive yarn structure of claim 1 wherein the insulating layer is substantially uniform in thickness.

5. A woven electrical network comprising:

(a) a first twisted pair conductive yarn structure being woven into a fabric in a first direction, the first twisted pair conductive yarn structure including first and second conductive yarns and at least one insulating layer for electrically isolating the first and second conductive yarns from each other, the first and second conductive yarns being twisted together to form a helical structure, the second conductive yarn being connected to ground;

(b) a second twisted pair conductive yarn structure being woven into the fabric in the first direction and being spaced from the first twisted pair yarn structure, the second twisted pair conductive yarn structure including first and second conductive yarns and at least one insulating layer for electrically isolating the first and second conductive yarns from each other, the first and second conductive yarns being twisted together to form a helical structure, the second conductive yarn being connected to ground; and

(c) an AC signal source being connected to the first conductive yarn of the first twisted pair conductive yarn structure for sending an AC signal over the first twisted pair conductive yarn structure, wherein the grounded second conductive yarns of the first and second twisted pair conductive yarn structures block electromagnetic fields emanating from the first conductive yarn of the first twisted pair conductive yarn structure and thereby reduce crosstalk between the first and second twisted pair conductive yarn structures.

6. The woven electrical network of claim 5 wherein conductive yarns of the first and second twisted pair conductive yarn structures each include a plurality of conductive strands being twisted together with each other.

7. The woven electrical network of claim 6 wherein the conductive strands comprise a conductive material selected from a group including metals, alloys, and conductive polymers.

8. The woven electrical network of claim 5 wherein the insulating layers comprise an electrically insulating material selected from a group including polyvinylchloride;

rubber;

rubber forming polymers, including polyisoprene, polybutadiene, polychloroprene, and polyisobutylene;

polyesters;

polyolefins; and

polyamides.

9. The woven electrical network of claim 5 wherein the insulating layers are substantially uniform in thickness.

10. The woven electrical network of claim 5 wherein the first and second twisted pair conductive yarn structures are spaced from each other in the fabric by a predetermined distance.

11. The woven electrical network of claim 10 wherein the predetermined distances ranges from about one hundredth of an inch to no more than about one inch.

12. The woven electrical network of claim 5 comprising a plurality of nonconductive yarns being woven in the fabric with the twisted pair conductive yarn structures.

13. The woven electrical network of claim 12 wherein the nonconductive yarns each comprise a material selected from a group including polyamides, including nylon;

polyurethane;

polyimides;

polyesters;

acrylics, acetate materials;

viscose materials; and

natural fibers, including wool, silk, and cotton.

14. The woven electrical network of claim 5 wherein the first and second twisted pair conductive yarn structures comprise warp yarns.

15. The woven electrical network of claim 5 wherein the first and second twisted pair conductive yarn structures comprise weft yarns.

16. A method for making a fabric-based signal transmission system, the method comprising:

(a) weaving a plurality of nonconductive threads together to form a fabric;

(b) twisting first and second insulated conductive threads together; and

(c) while twisting the first and second insulated conductive threads together, leno-weaving the first and second conductive threads into a first region of the fabric.

17. The method of claim 16 wherein performing steps (b) and (c) includes weaving the first and second conductive threads into the fabric in a first direction while simultaneously twisting the threads around adjacent nonconductive threads extending in a second direction in the fabric transverse to the first direction

18. The method of claim 16 wherein performing step (c) includes using a Jacquard loom equipped with leno headles.

19. The method of claim 16 wherein leno-weaving the first and second conductive threads into the fabric includes interlocking the first and second conductive threads with the nonconductive threads such that, in the first region, the first conductive thread is always on a first side of each of the nonconductive threads and the second conductive thread is always on a second side of each of the nonconductive threads, thereby forming a bottom doup leno weave.

20. The method of claim 16 wherein leno-weaving the first and second conductive threads into the fabric includes interlocking the first and second conductive threads with the nonconductive threads such that, in the first region, the first conductive thread alternates between first and second sides of adjacent nonconductive threads and the second conductive thread alternates between the second and first sides of the adjacent nonconductive threads.

21. The method of claim 16 comprising, in a second region of the fabric, ceasing steps (b) and (c) and weaving the first and second insulated conductive threads into the fabric.

22. The method of claim 21 wherein weaving the first and second insulated conductive threads into the fabric includes skipping at least one of the nonconductive threads and thereby creating a float to facilitate interconnection or disconnection with electrical devices.

23. The method of claim 16 wherein the first and second conductive threads form a twisted pair structure.

24. The method of claim 16 comprising, concurrently with step (c), leno weaving a third conductive thread into the fabric with the first and second conductive threads to form a coaxial structure.