RF tag, RF tag attitude detection apparatus, and RF tag attitude detection system

• US 20050225451A1
• Filed: 04/06/2005
• Published: 10/13/2005
• Est. Priority Date: 04/07/2004
• Status: Active Grant

• Current Assignee: Fujifilm Corporation (Fujifilm Holdings Corporation)
• Original Assignee: Fuji Photo Film Co Limited (Fujifilm Holdings Corporation)
• Inventors: Inui, Fuyuki
• Granted Patent: US 7,310,045 B2
• Time in Patent Office: Days
• US Class Current: 340/686.100
• CPC Class Codes: G01S 13/74 Systems using reradiation of radio waves, e.g. secondary radar systems; Analogous systems
• CPC Class Codes: G01S 5/0247 Determining attitude
• CPC Class Codes: G06K 7/10079 the collision being resolved in the spatial domain, e.g. temporary shields for blindfolding the interrogator in specific directions

Abstract

According to the present invention, the attitude of the article with the RF tag can be automatically detected by detecting the attitude of the directional antenna of the RF tag relative to that of the directional antenna of the RF tag attitude detection apparatus based on the signal intensity of the radio signal received from the RF tag.

Claims

1. An RF tag attitude detection apparatus, comprising:

a directional antenna which receives/transmits a radio signal from/to an RF tag;

an interrogator which measures the signal intensity of the radio signal received from the RF tag via the directional antenna; and

a detection section which detects the attitude of the RF tag based on the signal intensity measured by the interrogator.

2. The RF tag attitude detection apparatus according to claim 1, further comprising a plurality of the directional antennas having a directivity direction or polarization plane direction different from each other,

wherein the detection section compares the signal intensities obtained via the plurality of the directional antennas to detect the attitude of the RF tag.

3. The RF tag attitude detection apparatus according to claim 1, further comprising a direction changing section which causes a relative change in the directivity direction and/or polarization plane direction of the directional antenna and the attitude of the RF tag,

wherein the detection section detects the attitude of the RF tag based on the change of the signal intensity associated with the operation of the direction changing section.

4. The RF tag attitude detection apparatus according to claim 2, further comprising a direction changing section which causes a relative change in the directivity direction and/or polarization plane direction of the directional antenna and the attitude of the RF tag,

wherein the detection section detects the attitude of the RF tag based on the change of the signal intensity associated with the operation of the direction changing section.

5. The RF tag attitude detection apparatus according to claim 3, wherein the direction changing section changes electronically or mechanically the directivity direction and/or polarization plane direction of the directional antenna.

6. The RF tag attitude detection apparatus according to claim 4, wherein the direction changing section changes electronically or mechanically the directivity direction and/or polarization plane direction of the directional antenna.

7. The RF tag attitude detection apparatus according to claim 1, further comprising an antenna having a directivity broader than that of the directional antenna.

8. The RF tag attitude detection apparatus according to claim 6, further comprising an antenna having a directivity broader than that of the directional antenna.

9. The RF tag attitude detection apparatus according to claim 1, the interrogator writes into the RF tag the attitude information on the attitude of the RF tag detected by the detection section.

10. The RF tag attitude detection apparatus according to claim 6, the interrogator writes into the RF tag the attitude information on the attitude of the RF tag detected by the detection section.

11. The RF tag attitude detection apparatus according to claim 9, wherein the interrogator reads out the attitude information from the RF tag, whereby a process with respect to the RF tag is changed based on the attitude information.

12. The RF tag attitude detection apparatus according to claim 10, wherein the interrogator reads out the attitude information from the RF tag, whereby a process with respect to the RF tag is changed based on the attitude information.

17. An RF tag attitude detection system comprising the RF tag attitude detection apparatus of claim 1, and the RF tag of claim 13.

18. An RF tag attitude detection system comprising the RF tag attitude detection apparatus of claim 12, and the RF tag of claim 16.

13. An RF tag comprising a unidirectional antenna.

14. The RF tag according to claim 13, further comprising a display section which allows the directivity direction of the antenna to be visually determined from the outside.

15. The RF tag according to claim 13, wherein the antenna is a logperiodic antenna.

16. The RF tag according to claim 14, wherein the antenna is a logperiodic antenna.