Conductive pressure sensitive textile

• US 7,365,031 B2
• Filed: 04/02/2001
• Issued: 04/29/2008
• Est. Priority Date: 04/03/2000
• Status: Expired due to Fees

• Current Assignee: Intelligent Textiles Limited
• Original Assignee: Intelligent Textiles Limited
• Inventors: Peta-Thomson, Asha, Swallow, Stanley Shigezo
• Primary Examiner(s): Piziali; Andrew T
• Assistant Examiner(s): Choi; Peter Y
• Application Number:
  US10/240,567
• Publication Number:
  US 20030119391A1
• Time in Patent Office: 2,584 Days
• Field of Search: 442/228, 442/229, 442/192, 442/193, 442/195, 442/196, 442/301, 442/181, 442/203, 442/217, 442/197, 428/400, 428/402, 428/372, 428/376, 428/364, 428/365, 428/377, 174/68.1, 174/124.R, 738/620.46, 290/2, 345/173, 345/174, 178/18.05
• US Class Current: 442/181
• 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: G01L 1/20 by measuring variations in ohmic resistance of solid materials or of electrically-conductive fluids of piezo-resistive materials G01L1/18; by making use of electrokinetic cells, i.e. liquid-containing cells wherein an electrical potential is produced or varied upon the application of stress
• CPC Class Codes: G06F 3/045 using resistive elements, e.g. a single continuous surface or two parallel surfaces put in contact
• CPC Class Codes: H01H 2203/0085 Layered switches integrated into garment, clothes or textile
• CPC Class Codes: H01H 2203/01 Woven wire screen
• CPC Class Codes: Y10S 2/902 Antistatic
• CPC Class Codes: Y10T 428/2913 Rod, strand, filament or fiber
• CPC Class Codes: Y10T 428/2915 including textile, cloth or fabric
• CPC Class Codes: Y10T 428/2936 Wound or wrapped core or coating [i.e., spiral or helical]
• CPC Class Codes: Y10T 442/109 Metal or metal-coated fiber-containing scrim
• CPC Class Codes: Y10T 442/162 Including a natural or synthetic rubber layer
• CPC Class Codes: Y10T 442/30 Woven fabric [i.e., woven strand or strip material]
• CPC Class Codes: Y10T 442/3089 Cross-sectional configuration of strand material is specified
• CPC Class Codes: Y10T 442/3098 Cross-sectional configuration varies longitudinaly along the strand
• CPC Class Codes: Y10T 442/3114 Cross-sectional configuration of the strand material is other than circular
• CPC Class Codes: Y10T 442/3122 Cross-sectional configuration is multi-lobal
• CPC Class Codes: Y10T 442/313 Strand material formed of individual filaments having different chemical compositions
• CPC Class Codes: Y10T 442/3179 Woven fabric is characterized by a particular or differential weave other than fabric in which the strand denier or warp/weft pick count is specified
• CPC Class Codes: Y10T 442/3293 Warp and weft are identical and contain at least two chemically different strand materials
• 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 442/641 : Sheath-core multicomponent strand or fiber material
• CPC Class Codes: Y10T 442/642 : Strand or fiber material is a blend of polymeric material and a filler material
• CPC Class Codes: Y10T 442/649 : Plural foamed layers
• CPC Class Codes: Y10T 442/654 : Including a free metal or alloy constituent
• CPC Class Codes: Y10T 442/68 : Melt-blown nonwoven fabric
• CPC Class Codes: Y10T 442/682 : Needled nonwoven fabric

Abstract

A fabric including within its construction a first elongated electrical conductor crossed by a second elongated electrical conductor, the conductors being normally biased apart at a crossover point of said fibres with an air gap between them, whereby application of pressure in a direction substantially normal to a plane of the fabric causes the conductors to make contact. The fabric may be woven, knitted, non-woven or plaited. The fabric can be used as a pressure sensor, switch or other sensor.

Claims

1. A pressure sensor fabric provided with a single layer including warp and weft filaments within said single layer, wherein:

a. the warp filaments include at least one first elongated electrical conductor and the weft filaments include at least one second elongated electrical conductor,

b. the warp and weft filaments extend across and within a common plane within the layer, wherein the warp and weft fibers both include portions resting on opposite sides of the plane,

said first conductor or conductors being crossed by said second conductor or conductors, said conductors being normally biased apart at a crossover point of said conductors with an air gap between them resulting from insulating fibers or filaments which bias the first and second conductors apart at the crossover point wherein application of pressure in a direction substantially normal to a plane of the fabric is required to cause the conductors to make direct conductive contact wherein the air gap between them is closed with the conductors touching, with such contact changing the conductive properties of the fabric and thereby allowing sensing of the pressure.

2. A fabric according to claim 1, including a plurality of spaced first conductors and/or a plurality of spaced second conductors, forming a plurality of said crossover points.

3. A fabric according to claim 1, wherein said biasing apart is effected locating an electrical conductor of relatively smaller cross-section between insulating filaments or fibers of relatively larger cross-section.

4. A fabric according to claim 1, wherein the weave includes warp and/or weft floats over more than one yarn to effect the biasing apart of first and second electrical conductors at the crossover point.

5. A fabric according to claim 1, wherein said biasing apart is effected by employing, as at least one of the electrical conductors, an electrical conductor including insulating filament or fiber wound around it to leave the surface of the conductor exposed at the crossover point.

6. A fabric according to claim 1, wherein said biasing apart is effected by twisting at least one of the electrical conductors together with insulating filament or fiber.

7. A fabric according to claim 1, wherein said biasing apart is effected by employing, as at least one of the electrical conductors, a fiber including an insulating yarn and a conductive yarn, the insulating yarn including portions extending beyond the conductive yarn.

8. A fabric according to claim 7, wherein there are provided two or more conductive yarns helically wound around the insulating yarn.

9. A fabric according to claim 1, wherein the electrical conductors have an electrical property which is proportional to the length of the conductor, whereby the length of a conductor or plurality of connecting conductors can be determined from measurement of that property.

10. A fabric according to claim 1, including at least one set of spaced electrical conductors, at least some of said set being electrically connected together to form at least one bus bar.

11. A fabric according to claim 10, wherein said set of spaced electrical conductors comprises electrically conductive filaments or fibers in the warp or weft of a woven construction and electrical connection between conductors of that set is provided by one or more electrically conducting filaments or fibers in the well or warp, respectively.

12. A fabric according to claim 10, wherein said set of spaced electrical conductors comprises electrically conductive filaments or fibers in the warp or weft of a woven construction and said electrical connection is made after the weaving process.

17. A fabric according to claim 1 wherein the first conductor, second conductor, and insulating fibers are interwoven within the common plane.

18. A fabric according to claim 1 wherein the first conductor weaves above and below a plane wherein the second conductor is situated.

19. A fabric according to claim 1 wherein sections of both the first conductor and the second conductor are exposed on both of the opposite sides of the layer.

13. A pressure sensor fabric comprising a sheet which includes therein:

a. an elongated first conductor, and

b. an elongated second conductor crossing the first conductor,

c. an insulator maintaining the first and second conductors in spaced relation with an air gap therebetween at the location within the fabric at which the first and second conductors cross, the insulator running alongside at least one of the first and second conductors over a major portion of its length,

wherein;

(1) the first conductor, second conductor, and insulator are all present within a single layer of the fabric, wherein the first conductor, second conductor, and insulator all extend across and within a common plane, with the first conductor, second conductor, and insulator all having portions resting on opposite sides of the plane;

(2) applying pressure to a portion of the plane of the fabric is required to displace the insulator and move the first and second conductors into conductive contact with the first and second conductors touching each other, thereby changing the electrical properties of the fabric and providing a sensor signal indicative of the pressure.

14. The fabric of claim 13 wherein the diameter of the insulator is greater than the diameter of at least one of the conductors.

20. The fabric of claim 13 wherein the first conductor, second conductor, and insulator are interwoven within the common plane.

21. The fabric of claim 13 wherein the first conductor weaves above and below a plane wherein the second conductor is situated.

22. A fabric according to claim 13 wherein sections of both the first conductor and the second conductor face outwardly from both of the opposite sides of the layer.

15. A sheet of pressure sensor fabric comprising:

a. several elongated first conductors oriented in at least substantially parallel relationship, and

b. several elongated second conductors oriented in at least substantially parallel relationship, the second conductors crossing the first conductors,

c. several elongated insulators, each

i) extending alongside at least one of the first and second conductors over a major portion of its length and

ii) maintaining the first and second conductors in spaced relation with an air gap therebetween at the locations at which the first and second conductors cross

wherein;

(1) the first conductors, second conductors, and insulators are all present within a single layer of the fabric, wherein the first conductors, second conductors, and insulators all extend about a common plane, with the first conductors, second conductors, and insulators all having portions extending between opposite sides of the plane, and

(2) applying pressure to a portion of the plane of the fabric is required to move the first and second conductors into direct conductive contact with the first conductor touching the second conductor, thereby altering the conduction of the fabric to allow sensing of the pressure.

16. The sheet of claim 15 wherein each insulator extends alongside and in contact with at least one of the first and second conductors over a major portion of its length.

23. The sheet of claim 15 wherein the first conductors, second conductors, and insulators are interwoven within the common plane.

24. The sheet of claim 15 wherein the first conductors weave above and below a plane wherein the second conductors are situated.

25. The sheet of claim 15 wherein sections of both the first conductors and the second conductors are situated at outermost portions of both of the opposite sides of the layer.