RFID material tracking method and apparatus

• US 6,714,121 B1
• Filed: 08/09/1999
• Issued: 03/30/2004
• Est. Priority Date: 08/09/1999
• Status: Expired due to Fees

• Current Assignee: Round Rock Research LLC
• Original Assignee: Micron Technology, Inc.
• Inventors: Moore, Scott E.
• Primary Examiner(s): Horabik, Michael
• Assistant Examiner(s): Nguyen, Nam V
• Application Number:
  US09/371,717
• Time in Patent Office: 1,695 Days
• Field of Search: 340/10.1, 340/10.2, 340/10.3, 340/10.4, 340/10.32, 340/10.33, 340/10.42, 340/825.73, 340/825.49, 340/10.51, 340/568--56, 341/33
• US Class Current: 340/10.3
• CPC Class Codes: G06K 17/00 Methods or arrangements for effecting co-operative working between equipments covered by two or more of main groups G06K1/00 - G06K15/00, e.g. automatic card files incorporating conveying and reading operations
• CPC Class Codes: G06K 7/10336 the antenna being of the near field type, inductive coil
• CPC Class Codes: G08B 13/2462 Asset location systems combined with EAS inventory, tracking, logistic G06Q10/00; entrance control systems G07C9/00

Abstract

A method and apparatus for tracking items automatically is described. A passive RFID (Radio Frequency IDentification) tag is used with a material tracking system capable of real-time pinpoint location and identification of thousands of items in production and storage areas. Passive RFID tags are attached to the item to be tracked, remote sensing antennas are placed at each remote location to be monitored, interrogators with several antenna inputs are connected to the sensing antennas to multiplex the antenna signals, and a host computer communicates with the interrogators to determine item locations to an exacting measure.

Claims

1. An identification system, comprising:

a plurality of identification tags each attachable to an item to be identified;

a plurality of sensing antennas embedded within or upon one or more nesting stations that provide an identification tag location for each of the sensing antennas, the plurality of sensing antennas separate from the plurality of identification tags, each sensing antenna configured as a coil antenna coupled to a capacitor to form a tank circuit, each sensing antenna and its capacitor that forms a tank circuit in close proximity to each other; and

an interrogator having drive electronics and detection circuitry, the interrogator operatively attached to the sensing antennas to excite a single sensing antenna at a time, each sensing antenna polling its respective identification tag location to obtain information from an identification tag at the respective identification tag location through the sensing antenna when the sensing antenna is within a predetermined range of the identification tag.

2. The identification system of claim 1, wherein the identification tag is a radio frequency identification tag.

3. The identification system of claim 2, wherein the identification tag is a passive radio frequency identification tag.

4. The identification system of claim 1, wherein the identification tag is an active tag.

5. The identification system of claim 1, wherein the identification tag is a read only tag.

6. The identification system of claim 1, wherein the identification tag is a read/write tag.

7. The identification system of claim 1, wherein each sensing antenna is connected to the interrogator by a connection line comprising a cable, the cable having at each end a connection jack.

8. The identification system of claim 7, wherein the cable is a flat telephone cable.

9. The identification system of claim 7, wherein the connection jack is a telephone connection jack.

10. The identification system of claim 1, wherein each sensing antenna and its coupled capacitor are remote to the interrogator.

11. An identification system, comprising:

a plurality of sensing antennas embedded within or upon one or more nesting stations that provide an identification tag location for each of the sensing antennas, each sensing antenna configured as a coil antenna coupled to a capacitor to form a tank circuit, each sensing antenna and its capacitor that forms a tank circuit in close proximity to each other;

an interrogator having drive electronics and detection circuitry, the interrogator operatively attached to the sensing antennas to excite a single sensing antenna at a time, each sensing antenna polling a respective identification tag at its identification tag location when the tag is within a predetermined range of the sensing antenna, to obtain information from the identification tag through the sensing antenna, the sensing antenna separate from the identification tag; and

a plurality of telephone cable connection lines connecting the sensing antennas to the interrogator, each of the connection lines terminating in a line connection jack.

12. The identification system of claim 11, wherein each sensing antenna and its coupled capacitor are remote to the interrogator.

13. An RFID material tracking system, comprising:

an identification system comprising;

a plurality of RFID tags attachable to items to be tracked;

a plurality of sensing antennas embedded within or upon one or more nesting stations that provide an identification tag location for each of the sensing antennas, the plurality of sensing antennas separate from the plurality of RFID tags, each sensing antenna configured as a coil antenna coupled to a capacitor to form a tank circuit, each sensing antenna and its capacitor that forms a tank circuit in close proximity to each other; and

a plurality of interrogators, each interrogator having detection circuitry, drive electronics, and a plurality of antenna inputs, each of the plurality of antenna inputs operatively connected to one of the plurality of sensing antennas, wherein each sensing antenna obtains information from a tagged item when the tagged item is at the identification tag location of the sensing antenna within a predetermined range of the interrogator; and

a control system to control the driving of the sensing antennas such that only a single sensing antenna is driven at any one time.

14. The RFID system of claim 13, wherein the control system is a logic control system.

15. The RFID material tracking system of claim 13, wherein the control system is integrated into the interrogator.

16. The RFID material tracking system of claim 13, wherein the control system is external to the interrogator.

17. The RFID material tracking system of claim 13, wherein the control system comprises:

a computer operatively connected to each interrogator, the computer receiving tag location information from each interrogator to log tag location data.

18. The RFID material tracking system of claim 13, wherein the control system comprises:

an auxiliary processor board operatively connected to the interrogator to control operation of the interrogator, and to receive and store tag information from each interrogator.

19. The RFID material tracking system of claim 13, wherein the one or more nesting stations have a plurality of connection jacks to operatively connect the interrogator to the antennas via the jacks and a connection line to the interrogator.

20. The RFID material tracking system of claim 13, and further comprising:

a plurality of cable connection lines connecting the sensing antennas to the interrogator, each of the connection lines terminating in a connection jack.

21. The RFID material tracking system of claim 13, wherein each sensing antenna and its coupled capacitor are remote from its associated interrogator.

22. A material tracking system, comprising:

a plurality of RFID tags attachable to items to be tracked;

a plurality of sensing antennas embedded within or upon one or more nesting stations that provide an identification tag location for each of the sensing antennas, the plurality of sensing antennas separate from the plurality of RFID tags, each sensing antenna configured as a coil antenna coupled to a capacitor to form a tank circuit, each sensing antenna and its capacitor that forms a tank circuit in close proximity to each other; and

a plurality of interrogators, each interrogator having detection circuitry, drive electronics, and a plurality of antenna inputs, each of the plurality of antenna inputs operatively connected to one of the plurality of sensing antennas, wherein each sensing antenna obtains information from a tagged item when the tagged item is passed at the identification tag location of the sensing antenna within a predetermined range of the interrogator.

23. The material tracking system of claim 22, wherein each sensing antenna and its coupled capacitor are remote from its associated interrogator.

24. A material tracking system, comprising:

a plurality of RFID tags attachable to items to be tracked;

a plurality of sensing antennas embedded within or upon one or more nesting stations that provide an identification tag location for each of the sensing antennas, the plurality of sensing antennas separate from the plurality of RFID tags, each sensing antenna configured as a coil antenna coupled to a capacitor to form a tank circuit, each sensing antenna and its capacitor that forms a tank circuit in close proximity to each other; and

an interrogator having detection circuitry, drive electronics, and a plurality of antenna inputs, each of the plurality of antenna inputs operatively connected to one of the plurality of sensing antennas, wherein each sensing antenna obtains information from a tagged item when the tagged item is passed at the identification tag location of the sensing antenna within a predetermined range of the interrogator.

25. The material tracking system of claim 24, and further comprising:

a multiplexor operatively connected to each of the plurality of antenna inputs and to the drive electronics and to the detection circuitry; and

a processor operatively connected to the multiplexor to select one of the plurality of antennas to drive at any given time.

26. The material tracking system of claim 25, wherein the multiplexor and the processor are integrated with the interrogator.

27. The material tracking system of claim 25, wherein the processor is external to the interrogator.

28. The material tracking system of claim 24, and further comprising:

a plurality of cable connection lines connecting the sensing antennas to the interrogator, each of the connection lines terminating in a connection jack.

29. The material tracking system of claim 24, wherein each sensing antenna and its coupled capacitor are remote from the interrogator.

30. An RFID material tracking system, comprising:

a plurality of RFID tags, each tag attachable to an item to be tracked;

a plurality of sensing antennas separate from the plurality of RFID tags, each antenna placeable within or upon one or more nesting stations that provide at least a temporary holding location for the item to be tracked at a location to be monitored, each sensing antenna configured as a coil antenna coupled to a capacitor to form a tank circuit, each sensing antenna and its capacitor that forms a tank circuit in close proximity to each other;

a plurality of interrogators, each interrogator having a plurality of antenna inputs, each of the plurality of sensing antennas connected to an interrogator; and

a computer operatively connected to each of the interrogators and receiving tag location information therefrom to log tag location data.

31. The RFID material tracking system of claim 30, and further comprising a plurality of connection lines connecting the plurality of interrogators and the plurality of sensing antennas.

32. The RFID material tracking system of claim 30, wherein the connection lines are telephone cable.

33. The RFID material tracking system of claim 32, wherein the telephone connection lines are terminated at each end with a telephone connection jack.

34. The RFID material tracking system of claim 30, wherein each sensing antenna and its coupled capacitor are remote from its associated interrogator.

35. An identification system for tracking the location of a plurality of objects which may be at multiple locations, the identification system comprising:

a plurality of identification tags, each identification tag having a unique identification, and each identification tag attachable to an object;

a control module;

a plurality of interrogators, each interrogator placeable at a location at which objects are desired to be located, each interrogator operatively connected to a control module which initiates operations of the interrogator, and receives information gathered by the interrogator;

wherein each interrogator comprises drive electronics, detection circuitry, and an antenna for obtaining information from an identification tag when the interrogator and the identification tag are within a predetermined physical distance of one another, the antenna embedded within or upon a nesting station for holding one or more objects having an attached identification tag and configured as a coil antenna coupled to a capacitor to form a tank circuit, the antenna and its capacitor that forms a tank circuit are in close proximity to each other.

36. An identification system for tracking the location of a plurality of objects which may be at multiple locations, the identification system comprising:

a plurality of identification tags, each identification tag having a unique identification, and each identification tag attachable to an object;

a control module;

an interrogator placeable at a location at which objects are desired to be located, the interrogator operatively connected to a control module which initiates operations of the interrogator, and receives information gathered by the interrogator;

wherein the interrogator comprises drive electronics, detection circuitry, and an antenna for obtaining information from an identification tag when the interrogator and the identification tag are within a predetermined physical distance of one another, the antenna embedded within or upon a nesting station for holding one or more objects having an attached identification tag and configured as a coil antenna coupled to a capacitor to form a tank circuit, the antenna and its capacitor that forms a tank circuit are in close proximity to each other.

37. An interrogator for an RFID tracking system, comprising:

detection circuitry;

drive electronics; and

a plurality of antenna inputs each connectable to an antenna embedded within or upon a nesting station for holding one or more objects and configured as a coil antenna coupled to a capacitor to form a tank circuit, the antenna and its capacitor that forms a tank circuit are in close proximity to each other.

38. The interrogator of claim 37, and further comprising:

a processor; and

a multiplexor, the multiplexor operatively connected to the processor, the processor controlling the multiplexor selection of a single antenna input to drive at any given time.

39. The interrogator of claim 37, wherein each antenna to which the interrogator is coupled by one of the antenna inputs and its coupled capacitor are remote from the drive electronics.

40. An interrogator, comprising:

a plurality of antennas embedded within or upon one or more nesting stations for holding one or more objects, each antenna configured as a coil antenna coupled to a capacitor to form a tank circuit, each antenna and its capacitor that forms a tank circuit in close proximity to each other;

a drive electronics circuit for driving each of the plurality of antennas;

a processor;

a multiplexor operatively connected to each of the plurality of antennas, multiplexor selector input connected to the processor, the processor selecting the specific antenna to drive at any given time; and

a detection circuit operatively connected to the plurality of antennas, the detection circuit detecting a voltage in the driven antenna.

41. The interrogator of claim 40, wherein each antenna and its coupled capacitor are remote from the drive electronics.

42. An interrogator for an RFID tracking system, comprising:

a detection circuit;

drive electronics;

a multiplexor;

a plurality of antenna inputs, each antenna input operatively connected to the multiplexor and to the drive electronics, each antenna input connectable to an antenna embedded within or upon a nesting station for holding one or more objects and configured as a coil antenna coupled to a capacitor to form a tank circuit, the antenna and its capacitor that forms a tank circuit are in close proximity to each other; and

a microprocessor operatively connected to the multiplexor, the microprocessor controlling the operation of the multiplexor to select one of the antenna inputs to energize with the drive electronics.

43. The interrogator of claim 42, wherein each antenna to which the interrogator is coupled by one of the antenna inputs and its coupled capacitor are remote from the drive electronics.

44. A method of tracking the location of lots having RF identification tags attached thereto, the method comprising:

activating a sensing antenna embedded within or upon a nesting station for holding one or more lots having RF identification tag attached thereto using an interrogator by driving a tank circuit having a capacitor coupled to and in close proximity to the sensing antenna configured as a coil antenna;

determining if there is a sensed voltage at the sensing antenna from an identification tag, the sensing antenna separate from the identification tag;

obtaining tag data from the identification tag; and

transferring the obtained information from the interrogator to a computer.

45. The method of claim 44, and further comprising:

determining whether a tag is present at the tracking location.

46. The method of claim 45, and further comprising:

turning the carrier off and re-activating the sensing antenna if it is determined that a tag is not present.

47. The method of claim 44, and further comprising:

polling the next tag location if it is determined that a tag is not present at the current location.

48. A machine readable medium comprising machine readable instructions for causing a computer to perform a method comprising:

activating an antenna of an interrogator by driving a tank circuit having a capacitor coupled to and in close proximity to the antenna embedded within or upon a nesting station for holding a part having a passive identification tag attached thereto and configured as a coil antenna;

determining if there is a voltage at the antenna; and

obtaining data from the passive identification tag attached separate from the antenna to the part in the range of the interrogator.

49. A machine readable medium comprising machine readable instructions for causing a computer to perform a method comprising:

activating one of a plurality of antennas to poll a specific tag location by driving a tank circuit having a capacitor coupled to and in close proximity to the one antenna embedded within or upon a nesting station for holding an item having an identification tag attached thereto configured as a coil antenna;

determining whether a voltage due to an excited tag is present at the active antenna;

reading tag information from any tag at the specific tag location, the tag separate from the plurality of antennas;

deactivating the active antenna;

activating another of the plurality of antennas to poll a different specific tag location;

determining whether a voltage due to a second excited tag is present at the newly active antenna;

reading tag information from any tag at the different specific tag location, the tag separate from the plurality of antennas; and

repeating deactivating through reading until each of the plurality of antennas has been active.

50. The machine readable medium of claim 49, wherein the method further comprises:

waiting a predetermined time to detect a voltage in the active antenna if no voltage is present in the active antenna;

reading tag data from the tag associated with the active antenna if there is a voltage;

turning the active antenna off if after the predetermined time there is no voltage present in the active antenna;

turning the antenna back on to repower the tag at the tag location; and

repeating the determining through the reading until a voltage is detected in the active antenna or until a certain second predetermined time has elapsed.

51. A material tracking system, comprising:

a plurality of passive radio frequency identification tags attachable to lots to be tracked;

a plurality of sensing antennas separate from the plurality of passive radio frequency identification tags, each antenna placeable within or upon a nesting station that provides at least a temporary holding location for a lot to be tracked at a location to be monitored, each sensing antenna configured as a coil antenna coupled to a capacitor to form a tank circuit, each sensing antenna and its capacitor that forms a tank circuit in close proximity to each other;

a plurality of interrogators, each interrogator having a plurality of antenna inputs operatively connected to a multiplexor, and drive electronics and detection circuitry operatively connected to the multiplexor, each of the plurality of sensing antennas connected to an interrogator through its multiplexor; and

a computer operatively connected to each of the interrogator multiplexors to sequentially activate each of the sensing antennas to poll its specific location, the processor receiving tag location information from the detection circuitry to log tag location data.

52. The material tracking system of claim 51, wherein each antenna and its coupled capacitor are remote from its associated interrogator.

53. An inventory system, comprising:

a plurality of sensing antennas positioned at a plurality of lot locations, each sensing antenna embedded within or upon a nesting station that provides a lot location for the specific sensing antenna and configured as a coil antenna coupled to a capacitor to form a tank circuit, each sensing antenna and its capacitor that forms a tank circuit in close proximity to each other;

an interrogator operatively connected to each of the plurality of sensing antennas through a multiplexor, the interrogator comprising drive electronics, a detector circuit, and a processor, the processor operatively connected to the multiplexor to selectively drive one of the antennas at a time, the detector circuit detecting information of any identification tag at the lot location of the specific driven antenna, the identification tag separate from the plurality of sensing antennas.

54. The inventory system of claim 53, wherein each antenna and its coupled capacitor remote from the interrogator.

55. A lot tracking system, comprising:

a control module;

a plurality of interrogators each having a plurality of sensing antennas embedded within or upon one or more nesting stations, each sensing antenna positioned at a polling location within a nesting station, each sensing antenna configured as a coil antenna coupled to a capacitor to form a tank circuit, each sensing antenna and its capacitor that forms a tank circuit in close proximity to each other, each of the plurality of sensing antennas operatively connected to its respective interrogator through a multiplexor, a common detector circuit operatively connected to the multiplexor to detect information from the active sensing antenna, the control module operatively connected to each of the plurality of interrogators to control the sequential activation of each of the plurality of sensing antennas.

56. The lot tracking system of claim 55, wherein each antenna and its coupled capacitor are remote from its associated interrogator.

57. A method of polling a plurality of polling locations having identification tags thereat, the method comprising:

driving each of a plurality of sensing antennas one at a time with a common drive circuit to drive a tank circuit having a capacitor for each sensing antenna coupled to and in close proximity to the antenna, the plurality of sensing antennas embedded within or upon one or more nesting stations and separate from the identification tags;

polling a polling location within a nesting station with its specific sensing antenna;

detecting returned information for the specific polling location with a common detection circuit; and

translating the detected information to tag information.

58. The method of claim 57, and further comprising:

storing the tag information in a database.

59. The method of claim 57, wherein driving each of the plurality of sensing antennas one at a time comprises:

multiplexing the plurality of antennas with a multiplexor operatively controlled by a control module.

60. A method of polling a plurality of polling locations, comprising:

activating one of a plurality of multiplexed sensing antennas to excite a passive identification tag at the antenna location by driving a tank circuit having a capacitor coupled to and in close proximity to the sensing antenna configured as a coil antenna, the plurality of multiplexed sensing antennas embedded within or upon one or more nesting stations and separate from the passive identification tag;

detecting the voltage induced in the active sensing antenna with a common detection circuit;

translating detected voltage into identification tag information; and

sequentially activating each of the plurality of sensing antennas one at a time to poll each antenna location.