Detection system

• US 7,504,834 B2
• Filed: 12/20/2006
• Issued: 03/17/2009
• Est. Priority Date: 12/20/2006
• Status: Expired due to Fees

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Wang, Ding, Yu, Steven Y.
• Primary Examiner(s): Dole; Timothy J
• Assistant Examiner(s): Baldridge; Benjamin M
• Application Number:
  US11/613,670
• Publication Number:
  US 20080150555A1
• Time in Patent Office: 818 Days
• Field of Search: 324/693, 324/700, 324/71.2, 73/86, 202/404
• US Class Current: 324/693
• CPC Class Codes: G01D 5/35383 using multiple sensor devices using multiplexing techniques
• CPC Class Codes: G01M 11/085 the optical fiber being on or near the surface of the DUT
• CPC Class Codes: G01N 17/02 Electrochemical measuring systems for weathering, corrosion or corrosion-protection measurement

Abstract

A detection system for monitoring an engineered structure includes an array of sensors disposable in a predetermined pattern on the engineered structure and disposable between a surface of the engineered structure and a protective coating substantially covering the surface. The detection system also includes a controller in communication with the array of sensors for retrieving data from the sensors. The controller communicates with the sensor array via an optical fiber backbone. The array of sensors can remotely provide data corresponding to at least one of a degree of cure of the protective coating, a health of the cured protective coating, and a corrosion rate of the engineered structure at each of the sensors.

Claims

1. A detection system for monitoring a physical condition of an engineered structure, comprising:

an array of sensors disposable in a predetermined pattern on the engineered structure and disposable between a surface of the engineered structure and a protective coating substantially covering the surface, wherein at least one sensor of the array comprises a sensing portion configured to detect at least one of an impedance, current, and voltage, the sensing portion disposed on a flexible substrate, and an optoelectronic interface to receive the optical signal generated by the controller

a controller for retrieving data from the sensors, wherein the controller comprises a data acquisition system, a light source to generate the optical signal, an optical circulator, and an optical spectrum analyzer to receive returning optical signals from one or more of the sensors of the sensor array; and

one or more optical fibers coupling an optical signal generated by the controller to the array of sensors, wherein the array of sensors provides data corresponding to at least one of a degree of cure of the protective coating, a health of the cured protective coating, and a corrosion rate of the engineered structure at each of the sensors.

2. The detection system of claim 1, wherein the light source comprises at least one of a continuous broadband source, a tunable laser source, and a series of narrowband light sources.

3. The detection system of claim 1, further comprising a tap-off device coupled to an optical fiber of the one or more optical fibers to distribute a portion of the optical signal to a sensor of the sensor array, wherein a remaining portion of the optical signal is distributed to other sensors of the sensor array.

4. The detection system of claim 3, wherein the optoelectronic interface of the sensor comprises an optical signal demultiplexer to select a predetermined optical channel and to send the selected optical signal along a first optical path and a remaining portion of the optical signal along a second path.

5. The detection system of claim 4, wherein the optoelectronic interface of the sensor further comprises an electro-chromic switch disposed on the first optical path and a diode array disposed on the second optical path.

6. The detection system of claim 5, wherein the diode array comprises a PIN diode array that converts the remaining portion of the optical signal along the second path into an electrical signal that provides a power source for the electro-chromic switch.

7. The detection system of claim 6, wherein the electro-chromic switch includes at least first and second optically transmissive materials having a voltage-sensitive material disposed therebetween, wherein at least one of the optically transmissive materials further includes a high reflective coating disposed on a surface thereof.

8. The detection system of claim 7, wherein the electro-chromic switch reflects a portion of the selected optical signal back along a first optical path and that is received by the controller, wherein the amount of the reflected optical signal corresponds to a condition of the protective coating.

9. The detection system of claim 6, wherein an amount of power available to power the electro-chromic switch corresponds to an impedance due to the sensing portion.

10. The detection system of claim 4, wherein the demultiplexer comprises a thin-film channel selector.

11. The detection system of claim 1, wherein the sensing portion is disposable on a non-flat surface of the engineered structure.

12. The detection system of claim 1, wherein the sensing portion comprises a conductive element patterned as at least two electrodes on the flexible substrate.

13. The detection system of claim 1, wherein the engineered structure comprises one of a metal, a composite material, a ceramic material, and fiberglass material.

14. The detection system of claim 1, wherein at least one sensor in the array comprises a sensing portion configured to corrode when exposed to a corrosive environment.

15. The detection system of claim 1, wherein at least one sensor in the array comprises a sensing portion having a thickness of from about 13 μ

m to about 75 μ

m.

16. The detection system of claim 1, wherein a first optical signal received by the optical spectrum analyzer has a first wavelength and corresponds to a first sensor of the array and wherein a second optical signal received by the optical spectrum analyzer has a second wavelength, different from the first wavelength, and corresponds to a second sensor of the array.