Embeddable device for contactless interrogation of sensors for smart structures

• US 5,581,248 A
• Filed: 06/14/1993
• Issued: 12/03/1996
• Est. Priority Date: 06/14/1993
• Status: Expired due to Term

• Current Assignee: Simmonds Precision Products, Inc. (Rtx Corporation)
• Original Assignee: Simmonds Precision Products, Inc. (Rtx Corporation)
• Inventors: Spillman, William B. Jr., Durkee, Scott R.
• Primary Examiner(s): Peng, John K.
• Assistant Examiner(s): Wu, Daniel J.
• Application Number:
  US08/076,322
• Time in Patent Office: 1,268 Days
• Field of Search: 340/870.31, 340/870.32, 340/870.38, 340/825.54, 340/539, 340/568, 340/573, 340/870.37, 455/41, 342/50, 342/51, 73/763, 73/768, 73/769, 73/773
• US Class Current: 340/870.31
• CPC Class Codes: G01D 5/48 using wave or particle radiation means G01D5/26 takes precedence

Abstract

Sensing device for a sensor embeddable in a structure comprising: an insulative substrate, a circuit pattern disposed on the substrate for interconnecting a plurality of electronic components, the circuit pattern comprising an inductive coil, the circuit pattern including pads for disposing components on the substrate and coupling the device to the sensor.

Claims

1. Sensing device for a sensor embeddable in a structure, said sensing device comprising:

an insulative substrate, a circuit pattern disposed on said substrate for interconnecting a number of electronic components, said circuit pattern comprising an inductive coil, said coil comprising a plurality of windings disposed on one surface of said substrate and a plurality of windings disposed on another surface of said substrate, said substrate having pads for disposing said number of electronic components on said substrate and coupling the device to the sensor.

2. The sensing device of claim 1 wherein said substrate comprises a thin flexible piece of KAPTON insulator embeddable in the structure.

3. The sensing device of claim 2 wherein the structure comprises a non-magnetic composite material.

4. The sensing device of claim 1 wherein said device comprises surface mounted components including a capacitance connected to said coil as a resonant LC circuit.

5. The sensing device of claim 4 wherein said resonant circuit exhibits a resonant frequency greater than one megahertz.

6. The sensing device of claim 5 wherein the sensor is a resistive strain gauge.

7. The sensing device of claim 1 wherein said coil comprises a plurality of circularly spiraled windings such that said coil generates a doughnut shaped magnetic field perpendicular to the substrate surface.

8. The sensing device of claim 1 wherein said circuit pattern and coil are formed by etched conductive laminations on said substrate.

9. Sensing device for a sensor embeddable in a structure, said sensing device comprising:

first and second insulative substrates, a circuit pattern disposed on said first substrate for interconnecting a number of electronic components, said circuit pattern comprising an inductive coil, said first substrate having pads for disposing said number of electronic components on said substrate and coupling the device to the sensor, said second substrate having a second coil disposed thereon that is magnetically alignable with said first coil by overlaying said first and second substrates.

10. The sensing device of claim 9 wherein said first and second coils comprise etched copper traces on said substrates.

11. The sensing device of claim 9 wherein said second coil is connected to a high frequency energy source.

12. The sensing device of claim 11 wherein current produced in said first coil corresponds to a parameter of the sensor and induces a current in said second coil that is detected by a circuit connected to said second coil.

13. Apparatus for contactless interrogation of a sensor embeddable in a structure comprising a pair of substrates, circuit patterns respectively disposed on said substrates, each of said circuit patterns comprising a multiturn coil, said coils being of substantially identical configuration and concentrically overlayed during use to magnetically couple said coils, at least one of said substrates including surface mounted components comprising a resonant circuit connected to the sensor, said sensor connectable circuit substrate being embeddable in the structure.

14. The apparatus of claim 13 wherein said substrates comprise thin flexible pieces of nonmagnetic material.

15. The apparatus of claim 14 wherein said material comprises KAPTON insulator.

16. The apparatus of claim 13 wherein said coils comprise a coreless transformer.

17. The apparatus of claim 16 wherein during interrogation the sensor affects current flowing through said embeddable coil, said embeddable coil current inducing current through said other coil that can be detected and corresponds to a parameter of the sensor.

18. The apparatus of claim 17 wherein said sensor affects amplitude of current in said embeddable coil at a resonant frequency of said resonant circuit.

19. The apparatus of claim 18 embedded in a structure formed of composite material.

20. The apparatus of claim 19 wherein the sensor comprises a resistive strain gauge.

21. The apparatus of claim 20 wherein at least one of said substrates includes surface mounted components on both substrate surfaces.

22. The apparatus of claim 21 wherein said coils are etched laminations on said substrates.

23. The apparatus of claim 22 wherein said coils are etched on both substrate surfaces.