Disposable and trimmable wireless pressure sensor

• US 7,146,861 B1
• Filed: 10/18/2005
• Issued: 12/12/2006
• Est. Priority Date: 10/18/2005
• Status: Expired due to Fees

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Cook, James D., Liu, James ZT
• Primary Examiner(s): Lefkowitz, Edward
• Assistant Examiner(s): JENKINS, JERMAINE L
• Application Number:
  US11/253,530
• Time in Patent Office: 420 Days
• Field of Search: 73700-756
• US Class Current: 73/718
• CPC Class Codes: A61B 5/0215 by means inserted into the body catheters A61M25/00
• CPC Class Codes: G01D 21/00 Measuring or testing not otherwise provided for
• CPC Class Codes: G01D 5/185 using piezoelectric sensors
• CPC Class Codes: G01L 9/0025 with acoustic surface waves
• CPC Class Codes: G01L 9/007 using variations in inductance
• CPC Class Codes: G01L 9/0072 using variations in capacitance
• CPC Class Codes: G01L 9/008 using piezoelectric devices piezoelectric resonators G01L9/0022; surface acoustic waves G01L9/0025
• CPC Class Codes: G01L 9/08 by making use of piezoelectric devices , i.e. electric circuits therefor
• CPC Class Codes: G01L 9/10 by making use of variations in inductance , i.e. electric circuits therefor
• CPC Class Codes: G01L 9/12 by making use of variations in capacitance , i.e. electric circuits therefor

Abstract

A disposable pressure sensor includes a substrate and a pressure diaphragm formed upon the substrate. A sensor coil can be provided, comprising a capacitor and an inductor formed on the substrate and surrounded by the pressure diaphragm. The ferrite core is located proximate to the sensor coil, such that when the pressure diaphragm is exposed to a pressure, the diaphragm moves close to the inductor or the capacitor, thereby resulting in a change in the capacitor or the inductor and an indication of pressure. The capacitor can be implanted as an adjustable, trimmable or variable capacitor. The inductor may also be provided as an adjustable or variable inductor and can include the use of a variable capacitor and a PVDF based piezoelectric transducer. When the PVDF layer is under pressure, it can generate an electric field across the interdigital transducer and transmit a signal thereof through an antenna.

Claims

1. A disposable pressure sensor, comprising:

a substrate and a pressure diaphragm formed upon said substrate;

a sensor antenna connected to a capacitor formed on said substrate and surrounded by said pressure diaphragm; and

wherein said substrate is configured to include a gap in which a gel is located below a first bond layer and a PVDF layer formed thereon and wherein a second bond layer is formed above said PVDF layer followed by a layer of interdigital transducers, such that when said pressure diaphragm is exposed to a pressure, said diaphragm moves close to said PVDF layer or said capacitor, thereby resulting in an electric field change in said PVDF layer and at least one interdigital transducer among said layer of interdigital transducers to provide an indication of pressure.

2. The sensor of claim 1 wherein said capacitor comprises a variable capacitor.

3. The sensor of claim 1 wherein said capacitor is trimmed by a laser.

4. The sensor of claim 1 wherein said at least one interdigital transducer comprises a metal or a metal alloy.

5. The sensor of claim 4 wherein said metal comprises at least one of the following:

Cu, Al, Cr, Ag, Au, Pd, Ni, Cd, Zn, Mg, Fe, Sn, Pb, Ti, Ta, Sc, V, Mn, Co, W, Ir, or Pt.

6. The sensor of claim 4 wherein said metal alloy comprises binary, ternary or quadruple phase diagrams of metal or non-metal elements.

7. The sensor of claim 1 wherein said sensor antenna transmits a signal through RF radiation, wherein said signal comprises said indication of pressure.

8. The sensor of claim 7 further comprising a receiver that receives said signal transmitted wirelessly from said sensor antenna.

9. The sensor of claim 8 wherein said receiver collects frequency and signal strength data that is indicative of said pressure.

10. The sensor of claim 9 wherein the said at least one interdigital transducer collects energy from a piezoelectric effect associated with said PVDF layer.

11. The sensor of claim 9 further comprising a medical apparatus disposed proximate to said substrate and said sensor coil, wherein said medical apparatus comprises an interrogation system coil.

12. The sensor of claim 11 wherein said disposable pressure sensor is connected to a disposable cartridge.

13. The sensor of claim 11 wherein said disposable pressure sensor is connected to a tube set.

14. A disposable pressure sensor, comprising:

a substrate and a pressure diaphragm formed upon said substrate;

a sensor antenna connected to a variable capacitor formed on said substrate and surrounded by said pressure diaphragm, wherein said variable capacitor is trimmed by a laser; and

wherein said substrate is configured to include a gap in which a gel is located below a first bond layer and a PVDF layer formed thereon and wherein a second bond layer is formed above said PVDF layer followed by a layer of interdigital transducers, such that when said pressure diaphragm is exposed to a pressure, said diaphragm moves close to said PVDF layer or said variable capacitor, thereby resulting in an electric field change in said PVDF layer and at least one interdigital transducer among said layer of interdigital transducers to provide an indication of pressure, wherein said at least one interdigital transducer comprises a metal or a metal alloy.

15. The sensor of claim 14 wherein said metal comprises at least one of the following:

Cu, Al, Cr, Ag, Au, Pd, Ni, Cd, Zn, Mg, Fe, Sn, Pb, Ti, Ta, Sc, V, Mn, Co, W, Ir, or Pt.

16. The sensor of claim 14 wherein said metal alloy comprises binary, ternary or quadruple phase diagrams of metal or non-metal elements.

17. A disposable pressure sensor, comprising:

a substrate and a pressure diaphragm formed upon said substrate;

a sensor antenna connected to a capacitor formed on said substrate and surrounded by said pressure diaphragm;

a gap configured from said substrate, wherein a gel is located in said gap below a first bond layer and a PVDF layer formed thereon and wherein a second bond layer is formed above said PVDF layer followed by a layer of interdigital transducers, such that when said pressure diaphragm is exposed to a pressure, said diaphragm moves close to said PVDF layer or said capacitor, thereby resulting in an electric field change in said PVDF layer and at least one interdigital transducer among said layer of interdigital transducers to provide an indication of pressure; and

wherein said at least one interdigital transducer comprises a metal or a metal alloy, wherein said metal alloy comprises binary, ternary or quadruple phase diagrams of metal or non-metal elements, and wherein the said at least one interdigital transducer collects energy from a piezoelectric effect associated with said PVDF layer.

18. The sensor of claim 17 wherein said sensor antenna transmits a signal through RF radiation, wherein said signal comprises said indication of pressure.

19. The sensor of claim 18 further comprising a receiver that receives said signal transmitted wirelessly from said sensor antenna.

20. The sensor of claim 19 wherein said receiver collects frequency and signal strength data that is indicative of said pressure.