Carbon nanotube array based sensor

• US 6,946,851 B2
• Filed: 06/30/2003
• Issued: 09/20/2005
• Est. Priority Date: 07/03/2002
• Status: Expired due to Fees

• Current Assignee: Lawrence Livermore National Security LLC (Government of the United States of America)
• Original Assignee: Regents of the University of California (University of California)
• Inventors: Noy, Aleksandr, Swierkowski, Stephan P., Lee, Christopher L., Woods, Bruce W., Fisher, Karl A.
• Primary Examiner(s): Deb, Anjan
• Assistant Examiner(s): Nguyen, Hoai-An D.
• Application Number:
  US10/611,136
• Publication Number:
  US 20040004485A1
• Time in Patent Office: 813 Days
• Field of Search: 324/658, 324/649, 324/600, 324/515, 324/519, 324/548, 324/661, 324/686, 324/242, 324/243, 324/207.13, 324/207.22, 429/31, 429/140, 429/164, 429/166, 429/231.8, 422/105, 422/107, 422/108, 422/112, 257/24, 257/76, 257/254, 73/14.6, 73/14.8, 73/18.2, 73/405.A, 735/705, 731/701.3, 738/611.8, 738/612.3, 738/612.5, 738/612.6
• US Class Current: 324/658
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: G01R 15/16 using capacitive devices
• CPC Class Codes: Y10S 977/953 Detector using nanostructure

Abstract

A sensor system comprising a first electrode with an array of carbon nanotubes and a second electrode. The first electrode with an array of carbon nanotubes and the second electrode are positioned to produce an air gap between the first electrode with an array of carbon nanotubes and the second electrode. A measuring device is provided for sensing changes in electrical capacitance between the first electrode with an array of carbon nanotubes and the second electrode.

Claims

1. A sensor system, comprising:

a first electrode with

an array of carbon nanotubes, said array of carbon nanotubes including a multiplicity of individual carbon nanotubes,

a second electrode, said first electrode with an array of carbon nanotubes and said second electrode positioned to produce an air gap between said first electrode with an array of carbon nanotubes and said second electrode, and said first electrode with an array of carbon nanotubes and said second electrode positioned so that said individual carbon nanotubes do not contact said second electrode, and

means for sensing changes in electrical capacitance between said first electrode with an array of carbon nanotubes and said second electrode.

2. The sensor system of claim 1, wherein said means for sensing changes in electrical capacitance comprises means for measuring changes in the electrical capacitance across said air gap.

3. The sensor system of claim 1, wherein said means for sensing changes in electrical capacitance senses movement in said array of carbon nanotubes.

4. The sensor system of claim 1, wherein said means for sensing changes in electrical capacitance senses movement in said carbon nanotubes.

5. The sensor system of claim 1, wherein said sensor senses motion by said means for sensing changes in electrical capacitance sensing movement in said array of carbon nanotubes.

6. The sensor system of claim 1, wherein said sensor senses acceleration by said means for sensing changes in electrical capacitance sensing acceleration in said array of carbon nanotubes.

7. A sensor system, comprising:

a first electrode with

an array of carbon nanotubes,

a second electrode, said first electrode with an array of carbon nanotubes and said second electrode positioned to produce an air gap between said first electrode with an array of carbon nanotubes and said second electrode,

and

means for sensing changes in electrical capacitance between said first electrode with an array of carbon nanotubes and said second electrode, wherein said sensor senses sound by said means for sensing changes in electrical capacitance sensing movement in said array of carbon nanotubes caused by said sound.

8. A sensor system, comprising:

a first electrode with

an array of carbon nanotubes,

a second electrode, said first electrode with an array of carbon nanotubes and said second electrode positioned to produce an air gap between said first electrode with an array of carbon nanotubes and said second electrode,

and

means for sensing changes in electrical capacitance between said first electrode with an array of carbon nanotubes and said second electrode, wherein said sensor senses sound by said means for sensing changes in electrical capacitance sensing movement in said array of carbon nanotubes caused by sound waves.

9. The sensor system of claim 8, wherein said sensor senses flow by said means for sensing changes in electrical capacitance sensing movement in said array of carbon nanotubes caused by said flow.

10. The sensor system of claim 8, wherein said first electrode with an array of carbon nanotubes and said second electrode are positioned in an “

L”

shaped body.

11. A sensor system, comprising:

a first electrode with

an array of carbon nanotubes,

a second electrode, said first electrode with an array of carbon nanotubes and said second electrode positioned to produce an air gap between said first electrode with an array of carbon nanotubes and said second electrode,

and

means for sensing changes in electrical capacitance between said first electrode with an array of carbon nanotubes and said second electrode, wherein said first electrode with an array of carbon nanotubes and said second electrode are positioned in an “

L”

shaped body and wherein said “

L”

shaped body includes a base and a wall and wherein said first electrode with an array of carbon nanotubes is located in said base and said second electrode is positioned in said wall.

12. The sensor system of claim 11, wherein said first electrode with an array of carbon nanotubes and said second electrode are at a 90°

angle to each other.

13. The sensor system of claim 12, wherein said means for sensing changes in electrical capacitance measures movement of said base.

14. A sensor system, comprising:

a first electrode with

an array of carbon nanotubes,

a second electrode, said first electrode with an array of carbon nanotubes and said second electrode positioned to produce an air gap between said first electrode with an array of carbon nanotubes and said second electrode,

and

means for sensing changes in electrical capacitance between said first electrode with an array of carbon nanotubes and said second electrode, wherein said first electrode with an array of carbon nanotubes and said second electrode are positioned in concentric cylinders.

15. The sensor system of claim 14, wherein said concentric cylinders include an inner cylinder and an outer cylinder surrounding at least a portion of said inner cylinder.

16. The sensor system of claim 15, wherein said first electrode with an array of carbon nanotubes is located in inner cylinder and said second electrode is located in said outer cylinder.

17. The sensor system of claim 14, including a second array of carbon nanotubes on said second electrode.

18. The sensor system of claim 17, wherein said array of carbon nanotubes and said second array of carbon nanotubes are positioned adjacent and generally aligned with each other.

19. The sensor system of claim 18, wherein said sensor senses sound by said means for sensing changes in electrical capacitance senses relative movement in said array of carbon nanotubes and said second array of carbon nanotubes.

20. The sensor system of claim 19, wherein said sensor senses sound by said means for sensing changes in electrical capacitance senses relative movement in said array of carbon nanotubes and said second array of carbon nanotubes caused by said sound waves.

21. A method of producing a sensor, comprising the steps of:

providing a first electrode,

producing an array of carbon nanotubes that includes a multiplicity of individual nanotubes extending from said first electrode,

providing a second electrode,

positioning said first electrode with said array of carbon nanotubes and said second electrode in a position where there is an air gap between first electrode with said array of carbon nanotubes and said second electrode,

positioning said first electrode with said array of carbon nanotubes and said second electrode in a position where said individual carbon nanotubes will not contact said second electrode, and

providing a system for sensing changes in electrical capacitance between said first electrode with said array of carbon nanotubes and said second electrode.

22. The method of claim 21, wherein said means for sensing changes in electrical capacitance comprises means for measuring changes in the electrical capacitance across said air gap.

23. The method of claim 22, wherein said means for sensing changes in electrical capacitance senses movement in said array of carbon nanotubes.

24. The method of claim 21, wherein said means for sensing changes in electrical capacitance senses movement in said carbon nanotubes.

25. The method of claim 21, wherein said sensor senses motion by said means for sensing changes in electrical capacitance sensing movement in said array of carbon nanotubes.

26. The method of claim 21, wherein said sensor senses acceleration by said means for sensing changes in electrical capacitance sensing acceleration in said array of carbon nanotubes.

27. A method of producing a sensor, comprising the steps of:

providing a first electrode,

producing an array of carbon nanotubes extending from said first electrode;

providing a second electrode,

positioning said first electrode with said array of carbon nanotubes and said second electrode in a position where there is an air gap between first electrode with said array of carbon nanotubes and said second electrode, and

providing a system for sensing changes in electrical capacitance between said first electrode with said array of carbon nanotubes and said second electrode, wherein said sensor senses sound by said means for sensing changes in electrical capacitance sensing movement in said array of carbon nanotubes caused by said sound.

28. A method of producing a sensor, comprising the steps of:

providing a first electrode,

producing an array of carbon nanotubes extending from said first electrode,

providing a second electrode,

positioning said first electrode with said array of carbon nanotubes and said second electrode in a position where there is an air gap between first electrode with said array of carbon nanotubes and said second electrode, and

providing a system for sensing changes in electrical capacitance between said first electrode with said array of carbon nanotubes and said second electrode, wherein said sensor senses sound by said means for sensing changes in electrical capacitance sensing movement in said array of carbon nanotubes caused by sound waves.

29. The method of claim 28, wherein said sensor senses flow by said means for sensing changes in electrical capacitance sensing movement in said array of carbon nanotubes caused by said flow.

30. The method of claim 28, wherein said first electrode with an array of carbon nanotubes and said second electrode are positioned in an “

L”

shaped body.

31. A method of producing a sensor, comprising the steps of:

providing a first electrode,

producing an array of carbon nanotubes extending from said first electrode,

providing a second electrode,

positioning said first electrode with said array of carbon nanotubes and said second electrode in a position where there is an air gap between first electrode with said array of carbon nanotubes and said second electrode, and

providing a system for sensing changes in electrical capacitance between said first electrode with said array of carbon nanotubes and said second electrode, wherein said first electrode with an array of carbon nanotubes and said second electrode are positioned in an “

L”

shaped body and wherein said “

L”

shaped body includes a base and a wall and wherein said first electrode with an array of carbon nanotubes is located in said base and said second electrode is positioned in said wall.

32. The method of claim 31, wherein said first electrode with an array of carbon nanotubes and said second electrode are at a 90°

angle to each other.

33. The method of claim 32, wherein said means for sensing changes in electrical capacitance measures movement of said base.

34. The method of claim 31, wherein said first electrode with an array of carbon nanotubes and said second electrode are positioned in concentric cylinders.

35. The method of claim 34, wherein said concentric cylinders include an inner cylinder and an outer cylinder surrounding at least a portion of said inner cylinder.

36. The method of claim 35, wherein said first electrode with an array of carbon nanotubes is located in inner cylinder and said second electrode is located in said outer cylinder.

37. The method of claim 31, including a second array of carbon nanotubes on said second electrode.

38. The method of claim 37, wherein said array of carbon nanotubes and said second array of carbon nanotubes are positioned adjacent and generally aligned with each other.

39. The method of claim 38, wherein said sensor senses sound by said means for sensing changes in electrical capacitance senses relative movement in said array of carbon nanotubes and said second array of carbon nanotubes.

40. The method of claim 39, wherein said sensor senses sound by said means for sensing changes in electrical capacitance senses relative movement in said array of carbon nanotubes and said second array of carbon nanotubes caused by said sound waves.