Automatic mode detection in a dual operating mode RFID tag

• US 20060267736A1
• Filed: 05/31/2005
• Published: 11/30/2006
• Est. Priority Date: 05/31/2005
• Status: Active Grant

• Current Assignee: Amtech Systems LLC (Roper Technologies, Inc.)
• Original Assignee: TC License Limited
• Inventors: Weytjens, Filip, Gravelle, Kelly, Burnett, Matthew K., Johnson, Charles A., Scott, Dale L., Tiernay, Robert W.
• Granted Patent: US 8,198,985 B2
• Time in Patent Office: Days
• US Class Current: 340/10.510
• CPC Class Codes: G06K 19/0707 the arrangement being capable of collecting energy from external energy sources, e.g. thermocouples, vibration, electromagnetic radiation G06K19/0702 takes precedence
• CPC Class Codes: G06K 19/0712 the arrangement being capable of triggering distinct operating modes or functions dependent on the strength of an energy or interrogation field in the proximity of the record carrier active means for hindering electromagnetic reading or writing G06K19/07336
• 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 7/10198 setting parameters for the interrogator, e.g. programming parameters and operating modes
• CPC Class Codes: H04Q 5/22 the subordinate centre not permitting interconnection of subscribers connected thereto

Abstract

A multi-mode, preferably dual mode, radio frequency identification (RFID) tag is adapted for automatic detection of whether a RFID reader located within communication range of the RFID tag is transmitting a continuous wave (CW) or modulated wave types of RF signal, and accordingly, mandating a response from the tag in read-only (RO) mode or read/write (R/W) mode, respectively. The tag includes means for designating one of the RO and R/W operating modes as a default mode of the tag, and for switching the tag from its default mode to its other operating mode, and vice versa, according to a rule for determining the frequency of occurrence of a selected event related to signal type of the reader. A device-implemented method of this automatic detection, and a method of fabricating the tag, are also disclosed.

Claims

1. A device-implemented method of automatic detection by a dual mode radio frequency identification (RFID) tag adapted to operate in either of a read-only (RO) mode or a read/write (R/W) mode, of the operating mode asserted by the RF signal from a RFID reader located within communication range of the dual mode RFID tag that transmits one of a continuous wave (CW) type signal or a modulated type signal, so as to evoke a response from the dual mode RFID tag in said asserted mode, said method comprising the steps of assuming a programmed dominant one of said RO and R/W operating modes, and if the dominant mode is not said asserted mode, switching to the other of said operating modes according to a rule implemented to detect a selected event related to the signal type of the reader.

2. The device-implemented method according to claim 1, wherein said detection rule is implemented at least in part to determine the frequency of occurrence of said selected event over a designated time interval.

3. The device-implemented method according to claim 2, wherein said selected event is a falling edge of a waveform derived from the RF signal from a reader detected by said dual mode RFID tag.

4. The device-implemented method according to claim 2, wherein said detection rule is implemented in further part to compare the level of the RF signal from a reader detected by said dual mode RFID tag to a threshold level.

5. The device-implemented method according to claim 3, wherein said detection rule is implemented in further part to compare the level of the RF signal from a reader detected by said dual mode RFID tag to a preset threshold level.

6. The device-implemented method according to claim 3, wherein said programmed dominant operating mode is said RO mode.

7. The device-implemented method according to claim 1, wherein said dominant operating mode is the default mode of said tag, and including the step of reverting to the default mode each time the RF signal from a reader that asserted said other operating mode is no longer detected by said tag according to said detection rule.

8. The device-implemented method according to claim 1, wherein said dominant operating mode is the default mode of said tag, and said detection rule is implemented with criteria to establish a degree of reluctance that must be overcome for said tag to switch from said default mode to said other operating mode when asserted by an RF signal from a reader.

9. The device-implemented method according to claim 8, wherein said detection rule is implemented to establish a degree of acceptance of said tag considerably less stringent than said degree of reluctance, to switch from said other operating mode back to said default mode when asserted by an RF signal from a reader.

10. The device-implemented method according to claim 1, wherein said steps of assuming and switching are performed by a logic circuit of said tag.

11. A dual mode radio frequency identification (RFID) tag adapted to operate in either of a read-only (RO) mode or a read/write (R/W) mode, for automatic detection of the operating mode asserted by the RF signal from a RFID reader located within communication range of the dual mode RFID tag that transmits one of a continuous wave (CW) type signal or a modulated type signal, so as to evoke a response from the dual mode RFID tag in said asserted mode, said tag comprising circuit means for causing said tag to assume a programmed dominant one of said RO and R/W operating modes, and if the dominant mode is not said asserted mode, switching said tag to the other of said operating modes according to a rule implemented at least in part to determine frequency of occurrence of a selected event related to signal type of the reader over a designated time interval.

12. The RFID tag according to claim 11, wherein said selected event is a falling edge of a waveform derived from the RF signal from a reader detected by said dual mode RFID tag.

13. The RFID tag according to claim 11, wherein said rule is implemented in further part to compare the level of the RF signal from a reader detected by said dual mode RFID tag to a threshold level.

14. The RFID tag according to claim 12, wherein said rule is implemented in further part to compare the level of the RF signal from a reader detected by said dual mode RFID tag to a preset threshold level.

15. The RFID tag according to claim 12, wherein said programmed dominant operating mode is said RO mode.

16. The RFID tag according to claim 11, wherein said dominant operating mode is the default mode of said tag, and said circuit means causes said tag to revert to the default mode each time the RF signal from a reader that asserted said other operating mode is no longer detected by said tag.

17. The RFID tag according to claim 11, wherein said dominant operating mode is the default mode of said tag, and said is implemented to establish a degree of reluctance that must be overcome for said tag to switch from said default mode to said other operating mode when asserted by an RF signal from a reader.

18. The RFID tag according to claim 17, wherein said rule is implemented to establish a degree of acceptance of said tag considerably less stringent than said degree of reluctance, to switch from said other operating mode back to said default mode when asserted by an RF signal from a reader.

19. A method of fabricating a multi-mode radio frequency identification (RFID) tag adapted to operate in either of a read-only (RO) mode or a read/write (R/W) mode, for automatically detecting the operating mode mandated by the RF signal from a RFID reader located within communication range of the RFID tag, wherein said RF signal is one of a continuous wave (CW) type signal or a modulated type signal, so as to evoke a response from the RFID tag in said mandated mode, said method comprising the steps of implementing circuit means to adopt one of said RO and R/W operating modes as a default mode of said tag, and if the default mode is not said mandated mode, to switch said tag to the other of said operating modes according to a rule that imposes criteria to designate an event related to signal type of the reader and to determine frequency of occurrence of said designated event.

20. A multi-mode radio frequency identification (RFID) tag adapted for automatic detection of whether a RFID reader located within communication range of the RFID tag is transmitting a continuous wave (CW) or modulated wave type of RF signal, and accordingly, mandating a response from said tag in read-only (RO) mode or read/write (R/W) mode, respectively, said tag comprising means for designating one of said RO and R/W operating modes as a default mode of said tag, and for switching said tag from its default mode to its other operating mode, and vice versa, according to a rule for determining the frequency of occurrence of a selected event related to signal type of the reader.