Method and apparatus for detecting environmental conditions utilizing micro-electrical mechanical devices

• US 6,561,040 B1
• Filed: 01/14/1999
• Issued: 05/13/2003
• Est. Priority Date: 01/14/1999
• Status: Expired due to Fees

• Current Assignee: Lockheed Martin Corporation (Martin Marietta Corporation)
• Original Assignee: Lockheed Martin Corporation (Martin Marietta Corporation)
• Inventors: Kellogg, David L., Henderson, J. Kirston
• Primary Examiner(s): NOORI, MAX H
• Application Number:
  US09/231,472
• Time in Patent Office: 1,580 Days
• Field of Search: 737/63, 736/59, 735/143.8, 735/05, 735/141.5, 737/77, 737/75, 340/825.14, 340/10.1, 340/10.42, 340/10.6, 310/309, 136/244
• US Class Current: 73/763
• CPC Class Codes: G01D 3/022 having an ideal characteristic, map or correction data stored in a digital memory
• CPC Class Codes: G08C 17/00 Arrangements for transmitting signals characterised by the use of a wireless electrical link

Abstract

A system and method to measure physical conditions at an object under test. This system comprises at least one micro-electro mechanical die module placed proximate to the object under test. The micro-electro mechanical die module is formed on a substrate and consists of at least one micro-mechanical transducer to monitor physical conditions, a series of integrated circuits electrically connected to the micro-mechanical transducer in order to read the output of the transducer, an internal photo voltaic device located on the substrate, and a transmitter internal to the micro-electro mechanical die module connected to the integrated circuits and a first antenna. A second antenna gathers signals transmitted by the micro-electro mechanical die module. The micro-electro mechanical die module transmits a signal when the photo voltaic device is scanned by a coherent light source. A receiver electrically connected to the second antenna receives and amplifies the signals transmitted by the micro-electro mechanical die module. The signals transmitted by at least one micro-electro mechanical die module are received by the receiver and processed to obtain data representative of the physical conditions at the object under test from the signals.

Claims

1. A micro-electro mechanical device comprising:

a substrate;

at least one micro-mechanical transducer fabricated on the substrate;

a plurality of integrated circuits fabricated on the substrate electrically connected to at least one micro-mechanical transducer, and wherein the plurality of integrated circuits on the substrate contain a read only memory in which has been encoded an identification code unique to an individual micro-electro mechanical device, and wherein the unique identification code is included with an electromagnetic signal representing at least one parameter monitored by the micro-mechanical transducer;

an electrical power supply fabricated on the substrate electrically connected to the integrated circuits on the substrate;

a transmitter fabricated on the substrate electrically connected to the integrated circuits; and

an antenna fabricated on the substrate connected to the transmitter.

2. The micro-electro mechanical device of claim 1, wherein the electrical power supply is a photovoltaic device formed on the substrate.

3. The micro-electro mechanical device of claim 2, wherein the photovoltaic device is excited by a coherent light source external to the micro-electro mechanical device.

4. The micro-electro mechanical device of claim 3, wherein the coherent light source is a laser with a beam size no greater than the micro-electro mechanical device.

5. The micro-electro mechanical device of claim 1, wherein the micro-mechanical transducer monitors at least one of a group of characteristics consisting of temperature, pressure, vibrations, and acceleration on which the micro-electro mechanical device is placed.

6. The micro-electro mechanical device of claim 5, wherein the electrical power supply is at least one photo voltaic device, and wherein at least on photo voltaic device generates an electrical potential when illuminated by coherent light.

7. The micro-electro mechanical device of claim 6, further comprising.

a memory location in the integrated circuits on the substrate containing identification code unique to an individual micro-electro mechanical device, and wherein the unique identification code is included with an electromagnetic signal from the transmitter representing characteristics monitored by the micro-mechanical transducer.

8. A micro-electro mechanical device, comprising:

a substrate;

at least one micro-mechanical transducer fabricated on the substrate;

a plurality of integrated circuits fabricated on the substrate electrically connected to the micro mechanical transducer wherein the integrated circuits on the substrate contain a read only memory in which is encoded an identification code unique to the individual micro-electro mechanical device wherein the unique identification code is included with an electromagnetic signal representing at least one parameter monitored by the micro-mechanical transducer;

a power supply comprising at least one photovoltaic device electrically connected to the integrated circuits on the substrate;

a transmitter on the substrate electrically connected to the integrated circuits; and

an antenna on the substrate connected to the transmitter.

9. The micro-electro mechanical device of claim 8, wherein at least one photo voltaic device generates an electrical potential when illuminated by a coherent light source.

10. The micro-electro mechanical device of claim 9, wherein the coherent light source is a laser with a beam with a size no greater than the size of the micro-electro mechanical device and wherein the transmitter transmits an electromagnetic signal to an external receiver only when the photo voltaic device is illuminated by the coherent light source.

11. The micro-electro mechanical device of claim 10, wherein the micro-mechanical transducer monitors at least one of a group of characteristics consisting of temperature, pressure, vibrations, and acceleration on which the micro-electro mechanical device is places.

12. A method of monitoring physical parameters about a structure comprising the steps of:

providing at least one micro-electro mechanical device at a location proximate to the structure;

providing power to the micro-electro mechanical device from a source contained on or in the micro-electro mechanical device;

converting physical conditions to an output signal, at least one micro-mechanical transducer in the micro-electro mechanical device performing the conversion;

amplifying the output signal, a plurality of integrated circuits electrically connected to at least one micro-mechanical transducer in the micro-electro mechanical device performing the amplification;

encoding an identification code unique to an individual micro-electro mechanical device wherein the unique identification code is transmitted with an electro magnetic signal representing parameters monitored by the micro-mechanical transducer;

transmitting the electromagnetic signal to an external receiver;

receiving the electromagnetic signal, the external receiver; and

processing the electromagnetic signal to obtain data representative of the physical parameters monitored at the location of the micro-electro mechanical device.

13. The method of claim 12, wherein the step of providing power to the micro-electro mechanical device from a source contained on or in the micro-electro mechanical device further comprises:

illuminating the power supply of each of said at least one micro-electro mechanical devices individually with a coherent light source wherein the power supply comprises at least one photo voltaic device which generates an electrical potential when illuminated by the coherent light source and the power supply is electrically connected to the integrated circuits on the substrate.

14. The method of claim 13, wherein the step of transmitting the electromagnetic signal to an external receiver further comprises:

transmitting the electromagnetic signal to an external receiver only when at least one photovoltaic device is illuminated by the coherent light source.

15. The method of claim 12, wherein in the step of converting physical conditions to an output signal, the physical conditions converted are selected from the group consisting of pressure, temperature, vibrations, inertia and acceleration.

16. A system to measure physical conditions at an object under test comprising:

at least one micro-electro mechanical device placed proximate to the object under test, the micro-electro mechanical device comprising;

a substrate;

at least on micro-mechanical transducer fabricated on the substrate;

a plurality of integrated circuits fabricated on the substrate electrically connected to at least one micro-mechanical transducer;

an electrical power supply fabricated on the substrate electrically connected to the integrated circuits on the substrate;

a transmitter on the substrate electrically connected to the integrated circuits; and

a first antenna on the substrate connected to the transmitter;

a second antenna to gather signals transmitted by the micro-electro mechanical device;

a receiver electrically connected to the second antenna to receive and amplify the signals transmitted by the micro-electro mechanical device;

a processor, electrically connected to the receiver, that obtains data representative of the physical conditions at the object under test from the signals transmitted by the micro-electro mechanical device; and

a memory location in the integrated circuits on the substrate containing an identification code unique to an individual micro-electro mechanical device wherein the unique identification code is included with an electromagnetic signal from the transmitter representing acceleration date representative of an output signal generated by the micro-mechanical transducer.

17. The system of claim 16, wherein the electrical power supply is at least one photo voltaic device which generates an electrical potential when illuminated by coherent light, further comprising:

a coherent light source to emit a collimated beam of light having a path of propagation; and

a beam steering device placed in the path of propagation of the collimated beam of light to redirect the beam of light to individual micro-electro mechanical devices proximate to the object under test.

18. The system of claim 17, further comprising:

an array formed from a plurality of micro-electro mechanical devices placed proximate to the object under test.

19. The system of claim 18, wherein the beam steering device is commanded by a control signal to scan the array formed from a plurality of micro-electro mechanical devices wherein individual micro-electro mechanical devices are not simultaneously illuminated by the collimated beam of light.

20. The system of claim 17, further comprising:

an environmental chamber to isolate the object under test from a surrounding environment allowing controlled physical conditions of a test; and

a window transparent to the collimated beam of light allowing placement of the beam steering device external to the environmental chamber.

21. The system of claim 20, wherein the second antenna, the receiver and the processor are external to the environmental chamber.

22. The system of claim 20, wherein the environmental chamber is a wind tunnel.

23. The system of claim 18, further comprising:

a protective structure with an outer wall to protect the coherent light source, the beam steering device, the second antenna, the receiver and the processor from the physical conditions at the object under test; and

a window in the outer wall of the protective structure transparent to the collimated beam of light thus protecting the beam steering device from the physical conditions at the object under test.

24. The system of claim 23, wherein the outer wall of the protective structure comprises an exterior wall of a first vehicle and wherein the array is placed on the object under test.

25. The system of claim 24, wherein the object under test is a first aircraft on which is placed the array, and wherein at least one of the micro-electro mechanical devices is illuminated by the collimated beam of light originating from a second aircraft having the protective structure.

26. A method of sensing environmental data proximate to an object comprising the steps of:

providing at least one micro-electro mechanical device on an object, wherein the step of providing at least one micro-electro mechanical device on the object further comprises embedding or placing an array of micro-electro mechanical device in a surface of the object, and wherein the micro-electro mechanical device comprises;

a substrate;

at least one micro-mechanical transducer on the substrate;

a plurality of integrated circuits on the substrate electrically connected to the micromechanical transducer;

an electrical power supply located on the substrate electrically connected to the integrated circuits on the substrate, wherein the electrical power supply of the micro-electro mechanical device comprises a photo-voltaic device which generates an electrical potential to power the micro-electro mechanical device when illuminated by a beam of coherent light, and wherein the array of the micro-electro mechanical device on the object is scanned with a coherent light source wherein the coherent light source does not simultaneously illuminate multiple micro-electro mechanical devices in the array;

a transmitter on the substrate electrically connected to the integrated circuits; and

an antenna on the substrate connected to the transmitter, wherein said transmitter transmits the output signal from the micro-electro mechanical device to an external receiver;

converting environmental conditions at the object to an output signal representative of the environmental conditions, the micro-mechanical transducer on the micro-electro mechanical device performing the conversion;

transmitting the output signal from the micro-electro mechanical device to an external receiver;

receiving the output signal, the external receiver performing the reception; and

processing the output signal to obtain data representative of the environmental conditions at the micro-electro mechanical device on the object.

27. The method of claim 26, wherein in the step of providing at least one micro-electro mechanical device on an object, the electrical power supply of the micro-electro mechanical device comprises a photo-voltaic device which generates an electrical potential to power the micro-electro mechanical device when illuminated by a beam of coherent light.

28. The method of claim 26, wherein in the step of providing at least one micro-electro mechanical device on an object, the object is located inside a wind tunnel.