RADIO FREQUENCY IDENTIFICATION TRANSPONDER

• US 20070132556A1
• Filed: 10/03/2006
• Published: 06/14/2007
• Est. Priority Date: 02/28/2000
• Status: Active Grant

• Current Assignee: SATO Holdings Corporation
• Original Assignee: Michael Stanton, Stuart Littlechild
• Inventors: Littlechild, Stuart, Stanton, Michael
• Granted Patent: US 8,159,332 B2
• Time in Patent Office: Days
• US Class Current: 340/10.500
• 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: G06K 7/0008 General problems related to the reading of electronic memory record carriers, independent of its reading method, e.g. power transfer
• CPC Class Codes: G06K 7/10029 the collision being resolved in the time domain, e.g. using binary tree search or RFID responses allocated to a random time slot
• CPC Class Codes: G06K 7/10435 the interrogation device being positioned close to a conveyor belt or the like on which moving record carriers are passing conveying in accordance with bodily destination marks, see B65G47/46, sorting of objects carrying identity markings, see B07C5/34

Abstract

A radio frequency identification transponder including a power supply and a dynamic memory array which stores data. When power from the power supply ceases, the data in the dynamic memory array is validly maintained for a predetermined period of time. The dynamic memory array is responsive to an interrogating signal for selectively updating the data. A signal processor extracts an identifier from the interrogation signal and is responsive to the identifier and the stored data to determine whether some or all of the identifier is stored in the dynamic memory array.

Claims

1. A radio-frequency identification (“

RFID”

) transponder for use with an RFID;

interrogator that provides a plurality of temporally spaced interrogating signals, wherein the signals include respective identifiers, the RFID transponder comprising;

a receiver for receiving the plurality of temporally spaced interrogating signals from the RFID interrogator;

a memory array for storing first data; and

a signal processor responsive to the receiver for identifier extraction and responsive to an extracted identifier and the first data for determining whether some or all of the extracted identifier is stored in the memory array.

2. The RFID transponder according to claim 1 wherein at least some of the identifier is stored in the memory array and the stored at least some of the identifier updates at least some of the first data.

3. The RFID transponder according to claim 1 wherein the signal processor determines that the identifier is stored in the memory array if the identifier is different than the first data.

4. The RFID transponder according to claim 1 wherein the signal processor determines that the identifier is stored in the memory array if a predetermined portion of the identifier is different than the first data.

5. The RFID transponder according to claim 1 wherein the identifier includes data selected from at least one of the following types:

second data indicative of the interrogator; and

third data that is not constant between respective interrogating signals.

6. The RFID transponder according to claim 5 wherein the third data is indicative of timing of a respective interrogating signal.

7. The RFID transponder according to claim 5 wherein the third data is selected from the group consisting of a pseudo random number and a character string.

8. The RFID transponder according to claim 5 wherein the second data includes a reference number for the interrogator that is the same for all interrogating signals provided by the RFID interrogator.

9. The RFID transponder according to claim 8 wherein the third data includes a date stamp that varies with the passage of time.

10. The RFID transponder according to claim 5 wherein the signal processor determines that the second data is stored in the memory array if the second data is different than the first data.

11. The RFID transponder according to claim 5 wherein the signal processor determines that the third data is stored in the memory array if the second data is different than the first data.

12. The RFID transponder according to claim 11 wherein the signal processor determines that the second data is also stored in the memory array if the second data is different than the first data.

13. The RFID transponder according to claim 5 wherein the signal processor determines that the identifier is stored in the memory array if the third data is sufficiently different than at least some of the first data.

14. The RFID transponder according to claim 13 wherein:

the third data includes a date stamp indicative of the time of a respective interrogating signal; and

the date stamp is compared with the first data to determine whether sufficient time has elapsed since a last store of the third data in the memory array.

15. The RFID transponder according to claim 5 wherein:

the RFID transponder includes a transmitter for transmitting a reply signal to the interrogator in response to an interrogating signal; and

the reply signal includes fourth data indicative of the transponder and fifth data derived from the first data.

16. The RFID transponder according to claim 15 wherein the fifth data includes at least one of the second data and the third data.

17. The RFID transponder according to claim 15 wherein the fifth data includes the second data.

19. The RFID transponder according to claim 15 wherein the fifth data includes the second data and the third data.

20. The RFID transponder according to claim 15 wherein the fourth data is a coded string for allowing discrimination between other RFID transponders used with the interrogator.

18. The RFID transponder according to claim 33 wherein the fifth data includes the third data.

21. A method of using a radio-frequency identification (“

RFID”

) transponder with an RFID interrogator that provides a plurality of temporally spaced interrogating signals, wherein the temporally spaced interrogating signals include respective identifiers and the method includes the steps of;

receiving the temporally spaced interrogating interrogating signals from the interrogator with a receiver;

storing first data in a memory array; and

being responsive to the receiver for extracting the identifier from the interrogating signal and being responsive to the identifier and the first data for determining whether at least some of the identifier is stored in the memory array.