Sensor array

• US 4,795,998 A
• Filed: 12/03/1986
• Issued: 01/03/1989
• Est. Priority Date: 05/04/1984
• Status: Expired due to Fees

• Current Assignee: Raychem Limited (TE Connectivity Limited)
• Original Assignee: Raychem Limited (TE Connectivity Limited)
• Inventors: Dunbar, John H., Atkinson, Edward B.
• Primary Examiner(s): Goldberg, E. A.
• Assistant Examiner(s): LATEEF, MARVIN M
• Application Number:
  US06/938,346
• Time in Patent Office: 762 Days
• Field of Search: 338/5, 338/6, 338/208, 338/259, 338/270, 338/47, 174/117 M, 340/665, 340/666
• US Class Current: 338/5
• CPC Class Codes: G01L 1/205 using distributed sensing elements
• CPC Class Codes: G01L 9/0002 using variations in ohmic resistance G01L9/0051 takes precedence
• CPC Class Codes: G01L 9/02 by making use of variations in ohmic resistance, e.g. of potentiometers , electric circuits therefor, e.g. bridges, amplifiers or signal conditioning
• CPC Class Codes: H01H 13/785 characterised by the material of the contacts, e.g. conductive polymers
• CPC Class Codes: H01H 2201/036 Variable resistance
• CPC Class Codes: H01H 2203/0085 Layered switches integrated into garment, clothes or textile
• CPC Class Codes: H01H 2203/01 Woven wire screen

Abstract

A sensor array, usually a sensor matrix for sensing pressure, comprising a grid of conductors in a woven fabric, the row conductors crossing over the column conductors to form a matrix array of crossover points. The rows are separated from the columns by individually coating the conductors of one or both series with an electrically partially resistive fibrous material, so that when the conductors at any crossover point in the array are pressed closer together, the resistance between the two conductors at that crossover point decreases. By connecting the conductors to suitable electrical circuitry, the force applied at any crossover point and the location of that crossover point within the array can be determined.

Claims

1. A sensor matrix comprising first and second sets of conductors, the first set crossing over the second set to form a matrix of one or more crossover points, and being separated from the second set at least at one crossover point by an electrical transducer material, at least one of the sets being incorporated in a fabric.

2. A sensor according to claim 1 wherein each conductor in the first set and/or each conductor in the second set is individually surrounded by the electrical transducer material.

3. A sensor according to claim 1, wherein the transducer layer comprises electrically partially resistive material.

4. A sensor according to claim 3, wherein the partially resistive material has a resistivity at least 1000 times greater than that of the conductor with which it is associated and, if it is associated with two or more conductors of different resistivities, then it has a resistivity at least 1000 times greater than that of the conductor of the higher or highest resistivity.

5. A sensor according to claim 3, wherein the partially resistive material has a resistivity of at most 10¹⁰ ohm cm.

6. A sensor according to claim 1, wherein the first and second sets of conductors are in the form of a grid, the first set being a series of row conductors and the second set being a series of column conductors.

7. A sensor according to claim 1, wherein the fabric is a woven fabric.

8. A sensor according to claim 1, wherein the conductors are incorporated so that they project from one surface of the fabric.

9. A sensor according to claim 1, wherein the first set and the second set are both incorporated in a single fabric.

25. A sensor according to claim 1 arranged to provide a separately readable electrical change at any one or more cross-over points of conductors in the array when the condition to be sensed occurs at that or those point(s).

26. A sensor according to claim 1 wherein at least some of the conductors cross over in the array and the conductors are arranged so that application of pressure to any one crossover point in use will not cause significant movement at any adjacent crossover point.

10. A sensor matrix comprising first and second sets of conductors, the first set crossing over the second set to form a matrix of one or more crossover points, at least some of the conductors being at least partially surrounded individually by a transducer layer of fibres which are helically wound around the conductors, the layer being capable of acting to produce a detectable change in electrical properties in response to a condition to be sensed by the sensor.

11. A sensor according to claim 10, wherein each conductor in the first set and/or each conductor in the second set is individually surrounded by a layer of the fibres.

12. A sensor according to claim 10, wherein the transducer layer comprises two or more layers of the fibres.

13. A sensor according to claim 10, wherein the transducer layer comprises electrically partially resistive material.

14. A sensor according to claim 10, wherein the first and second sets of conductors are in the form of a grid, the first set being a series of row conductors and the second set being a series of column conductors.

15. A sensor according to claim 10, wherein at least one of the first set and the second set of conductors is incorporated in a single fabric.

16. A sensor according to claim 10, wherein, in addition to the electrical transducer layer, the conductors are surrounded by a layer of continuous or discontinuous electrically partially resistive or conductive material.

17. A sensor matrix comprising first and second sets of conductors, the first set crossing over the second set to form a matrix of crossover points, the conductors being substantially uniformly and individually surrounded by a layer of electrical transducer material capable of acting to provide a detectable change in electrical properties in response to a condition to be sensed by the sensor.

18. A sensor according to claim 17 wherein the electrical transducer material is a continuous, particulate or fibrous layer.

19. A sensor according to claim 17, wherein the electrical transducer material is a continuous layer and at least some of the conductors have been pre-coated with the continuous layer before incorporation in the sensor.

20. A sensor according to claim 17, wherein the transducer layer comprises electrically partially resistive material.

21. A sensor according to claim 17, wherein the first and second sets of conductors are in the form of a grid, the first set being a series of row conductors and the second set being a series of column conductors.

22. A sensor matrix comprising first and second sets of conductors, the first set crossing over the second set to form a matrix of one or more crossover points, the first set being separated from the second set by a hard elastic electrical transducer material.

23. A sensor matrix comprising first and second sets of conductors, the first set crossing over the second set to form a matrix of one or more crossover points, the first set being separated from the second set by a cross-linked polymeric electrical transducer material.

24. A sensor according to claim 23, wherein the polymer is an elastomer.