METHOD AND STRUCTURE FOR LOCALIZING OBJECTS USING DAISY CHAINED RFID TAGS

• US 20070257799A1
• Filed: 03/20/2007
• Published: 11/08/2007
• Est. Priority Date: 04/12/2006
• Status: Abandoned Application

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Marmigere, Gerard, Clement, Jean-Yves, Bauchot, Frederic, Picon, Joaquin
• Application Number:
  US11/688,270
• Publication Number:
  US 20070257799A1
• Time in Patent Office: Days
• US Class Current: 340/572.100
• CPC Class Codes: G06K 19/07749 the record carrier being capable of non-contact communication, e.g. constructional details of the antenna of a non-contact smart card
• CPC Class Codes: G06K 19/07796 arrangements on the record carrier to allow stacking of a plurality of similar record carriers, e.g. to avoid interference between the non-contact communication of the plurality of record carriers

Abstract

A Radio Frequency Identification (RFID) structure. The RFID structures includes a tag stack of N essentially identical RFID tags and an object stack of N essentially identical objects. N is at least 2. Each tag is attached to a corresponding object and includes an electronic chip, an antenna, and at least one pair of electrical contacts. The N tags are daisy chained together in electrical contact via the at least one pair of electrical contacts in the tags. The tag stack is configured to receive power from an external power source located outside of the RFID structure. A method for localizing an object in the object stack includes receiving an external signal in each tag via the antenna, and enabling or not enabling a lighting of a lighting device in each tag in dependence upon data in the external signal.

Claims

1. A Radio Frequency Identification (RFID) structure comprising a tag stack of N essentially identical RFID tags and an object stack of N essentially identical objects:

wherein N is at least 2;

wherein each tag of the N tags is attached to a corresponding object of the N objects;

wherein the N tags are denoted as T₁, T₂, . . . , T_N;

wherein each tag comprises an electronic chip, an antenna, and at least one pair of electrical contacts, said at least one pair of electrical contacts of T₁, T₂, . . . , T_N respectively denoted as C₁, C₂, . . . , C_N;

wherein the N tags are daisy chained together such that C_i is in electrical contact with C_i+1 for i=1, 2, . . . , N−

1;

wherein in each tag, the antenna is configured to receive an external signal from outside the RFID structure and to transmit the external signal to the chip which is configured to receive the signal from the antenna via an electrical connection between the antenna and the chip; and

wherein the tag stack is configured to receive power from an external power source located outside of the RFID structure.

2. The RFID structure of claim 1,

wherein T₁ is the only tag of the N tags configured to be directly electrically connected to the external power source;

wherein T₁ is configured to have power from the external power source enter the tag stack at C₁ and be transmitted to the N tags by being conducted through C₁, C₂, . . . , C_N; and

wherein in each tag, the chip is configured to receive the power conducted through the at least one pair of electrical contacts via an electrical connection between the at least one pair of electrical contacts and the chip.

3. The RFID structure of claim 2, wherein each tag does not comprise an internal power source that is internal to said each tag.

4. The RFID structure of claim 1,

wherein each tag comprises a lighting device;

and

wherein in each tag, the chip is electrically connected to the lighting device and is configured to enable or not enable a lighting of the lighting device, in dependence upon data in the external signal received by the chip from the antenna.

5. The RFID structure of claim 1, wherein in each tag, the at least one pair of electrical contacts consist of one pair of electrical contacts.

6. The RFID structure of claim 1, wherein in each tag, the at least one pair of electrical contacts comprises two pairs of electrical contacts.

7. The RFID structure of claim 6, wherein a first pair of the two pairs comprised by C_i is in electrical contact with a second pair of the two pairs comprised by C_i+1 such that the first pair within C_i does not spatially correspond to the second pair within C_i+1, for i=1, 2, . . . , N−

1.

8. The RFID structure of claim 6,

wherein each tag comprises a power controller electrically connected to each pair of the two pairs of electrical contacts;

and

wherein in each tag, only one pair of the two pairs of electrical contacts can be powered at any given time and the power controller is configured to determine which pair of the two pairs is powered by the conducted electrical power and is further configured to power the chip with the conducted electrical power in accordance with a predetermined polarity.

9. The RFID structure of claim 8, wherein in each tag, the power controller is configured to power a non-powered pair of the two pairs of electrical contacts that is not powered according to the predetermined polarity.

10. The RFID structure of claim 1, wherein T₁ is directly electrically connected to the external power source.

11. A method for localizing an object in a Radio Frequency Identification (RFID) structure that comprises a tag stack of N essentially identical RFID tags and an object stack of N essentially identical objects, said method comprising:

receiving by the N tags an external signal from outside the RFID structure,

wherein N is at least 2,

wherein each tag of the N tags is attached to a corresponding object of the N objects,

wherein the N tags are denoted as T₁, T₂, . . . , T_N,

wherein each tag comprises an electronic chip, an antenna, and at least one pair of electrical contacts, said at least one pair of electrical contacts of T₁, T₂, . . . , T_N respectively denoted as C₁, C₂, . . . , C_N,

wherein the N tags are daisy chained together such that C_i is in electrical contact with C_i+1 for i=1, 2, . . . , N−

1,

wherein the tag stack is receiving power from an external power source located outside of the RFID structure,

wherein each tag comprises a lighting device such that the chip in each tag is electrically connected to the lighting device in each tag,

wherein in each tag, the antenna receives the external signal; and

in each tag,

transmitting the external signal from the antenna to the chip via an electrical connection between the antenna and the chip,

receiving, by the chip, the external signal transmitted by the antenna,

extracting, by the chip, data in the external signal received by the chip, and

enabling or not enabling, by the chip, a lighting of the lighting device in dependence upon the extracted data.

12. The method of claim 11, wherein each tag stores a unique identifier of the object to which each tag is attached, wherein the data in the external signal comprises the unique identifier of one object of the N objects, and wherein the method further comprises:

in each chip,

ascertaining, by the chip, whether the unique identifier of the one object in the data in the external signal matches the stored unique identifier of the object to which the tag is attached;

enabling, by the chip, the lighting of the lighting device if said ascertaining has ascertained that the unique identifier of the one object in the data in the external signal matches the stored unique identifier of the object to which the tag is attached;

not enabling, by the chip, the lighting of the lighting device if said ascertaining has ascertained that the unique identifier of the one object in the data in the external signal does not match the stored unique identifier of the object to which the tag is attached.

13. The method of claim 11, wherein the lighting device is a light emitting diode (LED).

14. The method of claim 11,

wherein T₁ is the only tag of the N tags directly electrically connected to the external power source,

wherein power from the external power source enters the stack at C₁ and is transmitted to the N tags by being conducted through C₁, C₂, . . . , C_N, and

wherein in each tag, the chip receives the power conducted through the at least one pair of electrical contacts via an electrical connection between the at least one pair of electrical contacts and the chip.

15. The method of claim 11, wherein each tag does not comprise an internal power source that is internal to said each tag.

16. The method of claim 11, wherein in each tag, the at least one pair of electrical contacts consist of one pair of electrical contacts.

17. The method of claim 12, wherein in each tag, the at least one pair of electrical contacts comprises two pairs of electrical contacts.

18. The method of claim 17, wherein a first pair of the two pairs comprised by C_i is in electrical contact with a second pair of the two pairs comprised by C_i+1 such that the first pair within C_i does not spatially correspond to the second pair within C_i+1, for i=1, 2, . . . , N−

1.

19. The method of claim 17,

wherein each tag comprises a power controller electrically connected to each pair of the two pairs of electrical contacts in each tag;

wherein in each tag, only one pair of the two pairs of electrical contacts can be powered at any given time;

wherein the method further comprises;

in each tag,

determining, by the power controller, which pair of the two pairs is powered by the conducted power, and

powering the chip, by the power controller, with the conducted power in accordance with a predetermined polarity.

20. The method of claim 19, wherein the method further comprises:

in each tag, powering a non-powered pair of the two pairs of electrical contacts that is not powered according to the predetermined polarity.