SINGLE LAYER FORCE SENSOR

• US 20140076063A1
• Filed: 09/17/2013
• Published: 03/20/2014
• Est. Priority Date: 09/17/2012
• Status: Active Grant

• Current Assignee: Joyson Safety Systems Acquisition, LLC
• Original Assignee: TK Holdings Incorporated (Ningbo Junsheng Investment Group Co., Ltd.)
• Inventors: Lisseman, Jason, Andrews, David
• Granted Patent: US 9,696,223 B2
• Time in Patent Office: Days
• US Class Current: 73/862.68
• CPC Class Codes: B82Y 20/00 Nanooptics, e.g. quantum optics or photonic crystals
• CPC Class Codes: G01L 1/142 using capacitors
• 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

Abstract

A sensor for sensing an application of pressure is disclosed. The sensor includes a substrate, conductive elements and an electroactive layer. First and second conductive elements are supported on the substrate and have elongate edges spaced apart from each other. The electroactive layer has a common surface adhered against the conductive elements. The electroactive layer defines at least one electrical property in a portion of the layer between the conductive elements. The electrical property is configured to vary in relation to a magnitude of the pressure.

Claims

1. A sensor for sensing an application of pressure, the sensor comprising:

a substrate;

at least first and second conductive elements supported on the substrate and having elongate edges spaced apart from each other; and

an electroactive layer having a common surface adhered against the first and second conductive elements, the electroactive layer defining at least one electrical property in a portion of the electroactive layer between the first and second conductive elements, the electrical property configured to vary in relation to a magnitude of the pressure.

2. A sensor of claim 1, wherein the electrical property is a resistance.

3. A sensor of claim 1, further comprising a logic device connected to the first and second conductive elements and configured to determine the electrical property.

4. A sensor of claim 3, further comprising a power source connected to the first and second conductive elements and wherein the electrical property is a resistance generating a voltage difference between the first and second conductive elements and wherein the voltage difference varies in proportion to the magnitude of the pressure.

5. A sensor of claim 4, wherein the logic device includes a calibrator configured to determine the magnitude of the pressure using the voltage difference.

6. A sensor of claim 1, wherein the electroactive layer comprises at least one of a quantum tunneling composite, a nanotube doped ink or a doped carbon ink.

8. A sensor of claim 1, wherein the first and second conductive elements have a spiral pattern.

10. A sensor of claim 1, wherein the first conductive element includes a plurality of first fingers and the second conductive element includes a plurality of second fingers.

11. A sensor of claim 10, wherein the first fingers extend between the second fingers.

12. A sensor of claim 11, wherein the first fingers are in a parallel spaced array and wherein the second fingers are in a parallel spaced array.

13. A sensor of claim 12, wherein the first and second fingers alternate across the common surface to form a plurality of adjacent edges spaced apart from each other.

14. A sensor of claim 13, wherein the first and second fingers extend in different directions.

15. A sensor of claim 14, wherein the first fingers extend from a first trunk trace and wherein the second fingers extend from a second trunk trace.

16. A sensor of claim 15, wherein the first trunk trace has a first concavity and the second trunk trace has a second concavity and wherein the first and second concavities face each other.

17. A sensor of claim 16, wherein the first fingers extend into the first concavity in a direction opposite the second fingers extending into the second concavity.

18. A sensor of claim 17, wherein the fingers and trunks define a circular pressure sensitive region.

19. A sensor of claim 10, wherein at least one pair of first and second fingers has a closer spacing than another pair of first and second fingers.

20. A sensor of claim 19, wherein the closer spacing defines an area of higher sensitivity to the pressure.

21. A sensor of claim 10, wherein the electroactive layer has a varied resistance between different pairs of first and second fingers.

22. A sensor of claim 21, wherein the varied resistance is higher between at least one pair of first and second fingers or the varied resistance is lower between at least one pair of first and second fingers.

24. A sensor of claim 1, wherein the electrical property exhibits a characteristic curve.

25. A sensor of claim 24, wherein the characteristic curve at least partially varies as a function of a distance between the elongate edges.

26. A sensor of claim 25, wherein an increase of the distance increases a threshold for detection of the application of pressure.

27. A sensor of claim 26, wherein an increase of a width of the conductive elements increases the threshold for detection of the application of pressure.

28. A sensor of claim 27, wherein the increase of at least one of the distance or the width increases a radius of curvature of the characteristic curve.

35. A sensor of claim 1, wherein the electroactive layer is adhered against the conductive elements using an adhesive layer.

38. A sensor of claim 1, further comprising a coating deposited on the electroactive layer, wherein the coating is impermeable to water or the coating is configured to adjust a characteristic curve of the sensor.

45. A sensor of claim 38, wherein the coating adjusts the characteristic curve using at least one of a hardness, stiffness, thickness, material composition or shape.

47. A sensor of claim 1, wherein a portion of the electroactive layer includes an at least partially compliant molding, the compliant molding including a conductive polymer or a conductive elastomer.

52. A sensor of claim 1, further comprising a force-deflection element coupled to a side of the electroactive layer opposite the substrate.

53. A sensor of claim 52, wherein the force-deflection element includes a detent.

54. A sensor of claim 53, wherein the force-deflection element includes a secondary feature that decreases a contact area of the force-deflection element.

7. (canceled)

9. (canceled)

23. (canceled)

29-34. -34. (canceled)

36. (canceled)

37. (canceled)

39-44. -44. (canceled)

46. (canceled)

48-51. -51. (canceled)

55-64. -64. (canceled)