Radio frequency identification device

• US 20040160310A1
• Filed: 02/14/2003
• Published: 08/19/2004
• Est. Priority Date: 02/14/2003
• Status: Active Grant

• Current Assignee: Winbond Electronics Corporation
• Original Assignee: Winbond Electronics Corporation
• Inventors: Ho, Chin-Te, Chen, Mao-Song
• Granted Patent: US 7,005,965 B2
• Time in Patent Office: Days
• US Class Current: 340/10.2
• 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 7/10039 interrogator driven, i.e. synchronous

Abstract

The present invention provides a radio frequency identification (RFID) device including a detector and several identification tags. The detector transmits time slot cycle signals, and each of the cycle signals is divided into several slots. The identification tags receive the time slot cycle signal, and each of the tags respectively contains a random generator to generate a random number. Individual identification tag responds to the detector in an assigned time slot corresponding to a random number generated by the random generator in each single time slot cycle.

Claims

1. A radio frequency identification (RFID) device, comprising:

a detector transmitting a time slot cycle signal, wherein each of said time slot cycle signal is divided into several time slots; and

a plurality of tags receiving said time slot cycle signal, and responding to said detector in different time slot in each of said time slot cycle signal.

2. The RFID device according to claim 1, wherein each of said plurality of tags respectively contains a random generator to generate a random number, and responds to said detector in assigned time slot corresponding to said random number in each said single time slot cycle signal, wherein the range of said random number cannot exceed the number of said time slots.

3. The RFID device according to claim 2, wherein said random generator is a resonance circuit.

4. The RFID device according to claim 2, wherein said random generator generates a new random number in each of said time slot cycle signal.

5. The RFID device according to claim 1, wherein said time slot cycle signal is a 13.56 MHz of electromagnetic wave.

6. The RFID device according to claim 1, wherein a mute signal is used as an interval between said time slots, and four continuous mute signals are used as an interval between said time slot cycles.

7. A radio frequency identification (RFID) device, comprising:

a detector transmitting a time slot cycle signal, wherein each of said time slot cycle signal is divided into several time slots; and

a plurality of tags receiving said time slot cycle signal, and each of said plurality of tags respectively containing a random generator to generate a random number, wherein individual of said plurality of tags responds to said detector in assigned time slot corresponding to said random number in each of said time slot cycle signal, and said tag generates different random number in different time slot cycle.

8. The RFID device according to claim 7, wherein the range of said random number cannot exceed the number of said time slots.

9. The RFID device according to claim 7, wherein the steps of said detector detecting said plurality of tags, comprising:

transmitting a continuous time slot cycle signal, wherein each of said time slot cycle is divided into several time slots;

detecting all responses form said tags in the detection range, wherein said responses are in different time slots; and

counting the number of responses from said tags and comparing with a predetermined threshold to confirm the existence of said tags.

10. The RFID device according to claim 7, wherein a mute signal is used as an interval between said time slots, and four continuous mute signals are used as an interval between said time slot cycles.

11. A method for a detector identifying tags with the same identification code in a radio frequency identification (RFID) device, comprising:

transmitting a continuous time slot cycle signal, wherein each of said time slot cycle is divided into several time slots;

detecting all responses form tags in the detection range, wherein said responses are in different time slots; and

counting the number of responses from said tags and comparing with a predetermined threshold to confirm the existence of said tags.

12. The method according to claim 11, wherein said tag uses a random generator to decide the time slot of said response.

13. The method according to claim 11, wherein said tag responds to said detector in different time slot in each time slot cycle.

14. The method according to claim 11, wherein said time slot cycle signal is a 13.56 MHz of electromagnetic wave.

15. The method according to claim 11, wherein a mute signal is used as an interval between said time slots, and four continuous mute signals are used as an interval between said time slot cycles.