Mechanical deformation amount sensor

• US 6,848,320 B2
• Filed: 05/29/2003
• Issued: 02/01/2005
• Est. Priority Date: 07/19/2002
• Status: Expired due to Fees

• Current Assignee: Panasonic Electric Works Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Asahi Matsushita Electric Works Ltd. (Panasonic Holdings Corporation)
• Inventors: Sakai, Jun, Yabuta, Akira, Arakawa, Masao, Miyajima, Hisakazu
• Primary Examiner(s): Williams, Hezron
• Assistant Examiner(s): Rogers, David A.
• Application Number:
  US10/446,789
• Publication Number:
  US 20040012062A1
• Time in Patent Office: 614 Days
• Field of Search: 738/623.1, 738/623.91, 738/624.51, 738/624.71, 738/624.74, 738/626.21, 738/626.25
• US Class Current: 73/763
• CPC Class Codes: B81B 2201/0235 Accelerometers
• CPC Class Codes: B81B 2201/0257 Microphones or microspeakers
• CPC Class Codes: B81B 2201/0264 Pressure sensors
• CPC Class Codes: B81B 2203/0118 Cantilevers
• CPC Class Codes: B81B 2203/0127 Diaphragms, i.e. structures separating two media that can control the passage from one medium to another; Membranes, i.e. diaphragms with filtering function
• CPC Class Codes: B81B 3/0021 Transducers for transforming electrical into mechanical energy or vice versa dynamo-electric machines H02K99/00; electrostatic machines H02N1/00; piezoelectric devices H10N30/00
• CPC Class Codes: B81B 3/0086 Electrical characteristics, e.g. reducing driving voltage, improving resistance to peak voltage
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: G01L 9/0055 bonded on a diaphragm
• CPC Class Codes: G01P 15/123 by piezo-resistive elements, e.g. semiconductor strain gauges
• CPC Class Codes: G01P 2015/0828 the mass being of the paddle type being suspended at one of its longitudinal ends
• CPC Class Codes: Y10S 977/956 Of mechanical property

Abstract

A mechanical deformation amount sensor includes a sensor structure which is formed by a semiconductor substrate or an insulating substrate and integrally includes a deformation portion deformable, when a physical quantity to be detected is applied to the sensor structure, due to the physical quantity and a support portion for supporting the deformation portion, a carbon nanotube resistance element which is provided on the deformation portion so as to be mechanically deformed in response to deformation of the deformation portion and a wiring pattern which is formed in a pattern on the sensor structure so as to be connected to the carbon nanotube resistance element. By applying a voltage to the carbon nanotube resistance element via the wiring pattern, a change of electrical conductivity of the carbon nanotube resistance element upon mechanical deformation of the carbon nanotube resistance element is fetched as an electrical signal.

Claims

1. A mechanical deformation amount sensor, comprising:

a sensor structure formed by one of a semiconductor substrate and an insulating substrate and integrally includes a deformation portion deformable, when a physical quantity to be detected is applied to the sensor structure, due to the physical quantity and a support portion for supporting the deformation portion;

a first carbon nanotube resistance element provided on deformation portion to be mechanically deformed when the physical quantity to be detected is applied to said sensor structure;

a second carbon nanotube resistance element provided on said support portion that is not deformed when the physical quantity to be detected is applied to said sensor structure; and

a wiring pattern which is formed in a pattern on said sensor structure to be connected to said first carbon nanotube resistance element and said second carbon nanotube resistance element,

wherein a voltage is applied to the first and second carbon nanotube resistance elements via said wiring pattern such that a change of electrical conductivity of said first carbon nanotube resistance element upon mechanical deformation of said first carbon nanotube resistance element is fetched as an electrical signal.

2. The mechanical deformation amount sensor of claim 1, wherein said deformation portion is formed to be thinner than said support portion and is deformed to be deflected elastically when the physical quantity is applied to said sensor structure.

3. The mechanical deformation amount sensor of claim 1, wherein said sensor structure comprises a micro-electro-mechanical systems (MEMS) sensor chip formed by a silicon substrate.

4. The mechanical deformation amount sensor of claim 3, wherein said first carbon nanotube resistance element is provided on said deformation portion through an insulating film.

5. The mechanical deformation amount sensor of claim 1, wherein said first carbon nanotube resistance element is disposed such that a longitudinal direction of said first carbon nanotube resistance element is orthogonal to a direction of deformation of said deformation portion.

6. The mechanical deformation amount sensor of claim 1, wherein said wiring pattern has, at an end portion connected to said first carbon nanotube resistance element, a metal electrode such that each of opposite end portions of said first carbon nanotube resistance element is covered by said metal electrode.

7. The mechanical deformation amount sensor of claim 1, wherein a surface of said first carbon nanotube resistance element is covered by an insulating coating film.

8. The mechanical deformation amount sensor of claim 7, wherein said insulating coating film comprises a passivation film provided on a surface of said sensor structure.

9. The mechanical deformation amount sensor of claim 1, wherein the carbon nanotube resistance element is formed by a single-wall carbon nanotube.

10. The mechanical deformation amount sensor of claim 1, which acts as a pressure sensor having a fluid pressure as the physical quantity to be detected,

wherein in said sensor structure, said support portion is formed in a shape of a frame and said deformation portion is formed by a diaphragm occupying an inside space of said frame of said support portion such that said diaphragm bears the fluid pressure.

11. The mechanical deformation amount sensor of claim 10, wherein said carbon nanotube resistance element is provided at a peripheral edge portion of said diaphragm.

12. A mechanical deformation amount sensor, comprising:

a sensor structure formed by one of a semiconductor substrate or an insulating substrate and integrally including a deformation portion that is deformable, when a physical quantity to be detected is applied to said sensor structure, due to the physical quantity and a support portion for supporting said deformation portion;

a carbon nanotube resistance element provided on said deformation portion to be mechanically deformed in response to a deformation of said deformation portion; and

a wiring pattern formed in a pattern on said sensor structure to be connected to said carbon nanotube resistance element, wherein a voltage is applied to said carbon nanotube resistance element via said wiring pattern, such that a change of electrical conductivity of said carbon nanotube resistance element upon mechanical deformation of said carbon nanotube resistance element is fetched as an electrical signal, a reference resistance element being provided at a portion of said sensor structure other than said deformation portion, said reference resistance element and said carbon nanotube resistance element being connected to each other by said wiring pattern to form a bridge circuit.

13. The mechanical deformation amount sensor of claim 12, wherein said reference resistance element comprises a carbon nanotube.

14. A mechanical deformation amount sensor, comprising:

a sensor structure formed by one of a semiconductor substrate or an insulating substrate and integrally including a deformation portion that is deformable, when a physical quantity to be detected is applied to said sensor structure, due to the physical quantity and a support portion for supporting said deformation portion;

a carbon nanotube resistance element provided on said deformation portion to be mechanically deformed in response to a deformation of said deformation portion; and

a wiring pattern formed in a pattern on said sensor structure to be connected to said carbon nanotube resistance element, wherein a voltage is applied to said carbon nanotube resistance element via said wiring pattern, such that a change of electrical conductivity of said carbon nanotube resistance element upon mechanical deformation of said carbon nanotube resistance element is fetched as an electrical signal, a step portion being formed on said deformation portion, said carbon nanotube resistance element being provided on said deformation portion so as to stride over said step portion.

15. A mechanical deformation amount sensor, comprising:

a sensor structure formed by one of a semiconductor substrate or an insulating substrate and integrally including a deformation portion that is deformable, when a physical quantity to be detected is applied to said sensor structure, due to the physical quantity and a support portion for supporting said deformation portion;

a carbon nanotube resistance element provided on said deformation portion to be mechanically deformed in response to a deformation of said deformation portion; and

a wiring pattern formed in a pattern on said sensor structure to be connected to said carbon nanotube resistance element, wherein a voltage is applied to said carbon nanotube resistance element via said wiring pattern, such that a change of electrical conductivity of said carbon nanotube resistance element upon mechanical deformation of said carbon nanotube resistance element is fetched as an electrical signal, said carbon nanotube resistance element being formed by a single-wall carbon nanotube, wherein said carbon nanotube resistance element is formed by a plurality of single-wall carbon nanotubes which are arranged side by side and are electrically connected to each other in parallel.

16. A mechanical deformation amount sensor, comprising:

a sensor structure formed by one of a semiconductor substrate or an insulating substrate and integrally including a deformation portion that is deformable, when a physical quantity to be detected is applied to said sensor structure, due to the physical quantity and a support portion for supporting said deformation portion;

a carbon nanotube resistance element provided on said deformation portion to be mechanically deformed in response to a deformation of said deformation portion; and

a wiring pattern formed in a pattern on said sensor structure to be connected to said carbon nanotube resistance element, wherein a voltage is applied to said carbon nanotube resistance element via said wiring pattern, such that a change of electrical conductivity of said carbon nanotube resistance element upon mechanical deformation of said carbon nanotube resistance element is fetched as an electrical signal, said mechanical deformation amount sensor acting as an acceleration sensor having an acceleration as the physical quantity to be detected,

wherein said sensor structure further includes a weight portion integrally coupled with said support portion by said deformation portion.