SPATIALLY DISTRIBUTED REMOTE SENSOR

• US 20080061965A1
• Filed: 09/06/2006
• Published: 03/13/2008
• Est. Priority Date: 09/06/2006
• Status: Active Grant

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Free, M. Benton, Kuhns, David W.
• Granted Patent: US 7,948,380 B2
• Time in Patent Office: Days
• US Class Current: 340/539.22
• CPC Class Codes: G06K 19/0672 with resonating marks
• CPC Class Codes: G06K 19/0717 the sensor being capable of sensing environmental conditions such as temperature history or pressure
• CPC Class Codes: G06K 19/0723 the record carrier comprising an arrangement for non-contact communication, e.g. wireless communication circuits on transponder cards, non-contact smart cards or RFIDs
• CPC Class Codes: H04B 5/0043 for taking measurements, e.g. using sensor coils
• CPC Class Codes: H04B 5/0056 for use in interrogation, identification or read/write systems record carriers G06K7/00, G06K19/00; for railways B61L3/12
• CPC Class Codes: H04B 5/0062 in RFID [Radio Frequency Identification] Systems
• CPC Class Codes: H04B 5/02 using transceiver
• CPC Class Codes: H04B 5/48 Transceivers
• CPC Class Codes: H04B 5/73 for taking measurements, e.g. using sensing coils
• CPC Class Codes: H04B 5/77 for interrogation

Abstract

A remote sensing device includes a plurality of components arranged to form a resonant electrical circuit. The plurality of components includes at least one sensing component having sensing elements distributed among regions of an area of interest. The sensing elements are arranged so that a resonant characteristic of the resonant circuit is modifiable by an external event affecting an element associated with a region. The sensing component may be a capacitor having spatially distributed capacitive elements or an inductor having spatially distributed inductive elements.

Claims

1. A remote sensing device comprising a plurality of components including at least an inductor and a capacitor arranged to form a resonant electrical circuit, at least one component of the plurality of components having elements distributed among regions of an area of interest, the elements arranged so that a resonant characteristic of the resonant circuit is modifiable by an external event affecting an element associated with a region.

2. The device of claim 1, wherein the at least one component comprises a capacitor and the elements comprise capacitive elements.

3. The device of claim 1, wherein the at least one component comprises an inductor and the elements comprise inductive elements.

4. The device of claim 1, wherein the external event comprises exposure of the element to an environmental condition.

5. The device of claim 1, wherein the external event comprises disconnection of the element from the resonant electrical circuit.

6. The device of claim 1, wherein the external event comprises short circuiting the element.

7. The device of claim 1, wherein:

the area of interest comprises a ticket object and one or more of the elements are associated with individual tickets of the ticket object; and

the external event comprises removal of an individual ticket from the ticket object.

8. The device of claim 1, wherein:

the area of interest comprises a medical dressing and the elements are distributed among the regions of the medical dressing; and

the external event comprises exposure of the medical dressing to a fluid.

9. The device of claim 1, wherein:

the area of interest comprises an object dispenser and the regions are associated with object containers of the object dispenser; and

the external event comprises removal of an object from an object container.

10. The device of claim 1, wherein the area of interest comprises a gauge having calibrated regions, the regions calibrated to measure the external event.

11. The device of claim 1, wherein the external event causes a change in an electrical parameter of the at least one component.

12. The device of claim 1, wherein:

the external event alters a material property associated with the element; and

the alteration of the material property causes a change in an electrical parameter of the at least one component.

13. The device of claim 1, wherein the resonant characteristic comprises a resonant frequency.

14. A method for sensing external events using a remote sensing device having components including at least an inductor and a capacitor forming a sensing circuit having a resonant frequency, at least one component of the remote sensing device comprising a number of sensing elements, the method comprising:

respectively associating the sensing elements with regions of an area of interest; and

modifying the resonant frequency of the circuit based on an external event affecting a sensing element associated with a region.

15. The method of claim 14, wherein respectively associating the sensing elements with the regions comprises positioning each sensing element relative to an associated region.

16. The method of claim 14, wherein modifying the resonant frequency based on the external event comprises modifying the resonant frequency based on exposure of the sensing element to an environmental condition.

17. The method of claim 14, further comprising:

detecting the modified resonant frequency; and

interpreting the modified resonant frequency as indicating an occurrence of the external event.

18. The method of claim 17, further comprising using a reference signal in the interpretation of the modified resonant frequency.

19. The method of claim 18, wherein using the reference signal comprises normalizing a signal produced by the sensing circuit based on the reference signal.

20. A remote sensing system, comprising:

a device comprising a plurality of components including at least an inductor and a capacitor arranged to form a sensing circuit having a resonant characteristic, at least one component of the plurality of components comprising elements respectively associated with regions of an area of interest, the elements arranged so that a resonant characteristic of the sensing circuit is modifiable by an external event affecting an element associated with a region; and

an interrogator configured to detect the resonant characteristic.

21. The system of claim 20, wherein the interrogator is configured to interpret the modification of the resonant characteristic as indicating an occurrence of the external event.

22. The system of claim 20, further comprising a reference circuit isolated from the external event and configured to produce a reference signal.

23. The system of claim 22, wherein the interrogator is configured to use the reference signal to interpret a modification of the resonant characteristic as indicating an occurrence of the external event.

24. The system of claim 22, wherein the interrogator is configured to use the reference signal to normalize a signal of the sensing circuit with respect to at least one of distance and orientation relative to the interrogator.

25. The system of claim 20, wherein the regions comprise ticket objects and the interrogator is disposed in a dispenser of the ticket objects.

26. The system of claim 20, wherein the regions comprise accessible sections of a blister pack and the interrogator is disposed in a blister pack dispenser.

27. A system for sensing external events affecting regions of an area of interest, comprising:

means for producing signal based on the resonant frequency of a resonant circuit having at least one component comprising elements distributed among the regions; and

means for modifying the signal responsive to an external event affecting an element associated with a region.

28. The system of claim 27, further comprising modifying the signal based on exposure of the element associated with the region to an environmental condition.

29. The system of claim 27, further comprising:

means for measuring the modified signal; and

means for interpreting the modified signal as indicating an occurrence of the external event.

30. The system of claim 27, further comprising:

means for producing a reference signal; and

means for using the reference signal in the interpretation of the modified signal.