Systems and methods for verification of security tag detachment

• US 9,390,602 B2
• Filed: 03/11/2014
• Issued: 07/12/2016
• Est. Priority Date: 03/11/2013
• Status: Active Grant

• Current Assignee: Sensormatic Electronics LLC (Johnson Controls International plc)
• Original Assignee: Tyco Fire & Security GmbH (Johnson Controls International plc)
• Inventors: Patterson, Hubert A., Hall, Stewart E., Maitin, Steve
• Primary Examiner(s): Wang, Jack K
• Application Number:
  US14/204,302
• Publication Number:
  US 20140253333A1
• Time in Patent Office: 854 Days
• Field of Search: 340/572.4, 340/572.9, 340/572.7, 340/568.1
• US Class Current: 1/1
• CPC Class Codes: E05B 73/0017 Anti-theft devices, e.g. tags or monitors, fixed to articles, e.g. clothes, and to be removed at the check-out of shops
• CPC Class Codes: E05B 73/0064 of the mechanical type
• CPC Class Codes: G08B 13/2434 Tag housing and attachment details
• CPC Class Codes: G08B 13/2448 Tag with at least dual detection means, e.g. combined inductive and ferromagnetic tags, dual frequencies within a single technology, tampering detection or signalling means on the tag
• CPC Class Codes: G08B 13/246 Check out systems combined with EAS, e.g. price information stored on EAS tag anti-theft systems in point of sale systems G07G3/003
• CPC Class Codes: G08B 13/248 EAS system combined with another detection technology, e.g. dual EAS and video or other presence detection system
• CPC Class Codes: G08B 13/2482 EAS methods, e.g. description of flow chart of the detection procedure

Abstract

Systems (100) and methods (1400) for verifying a detachment of a security tag (108) from an article. The methods comprise: producing by a detaching unit (106) a first signal at a first frequency and a second signal at a second frequency when the security tag is in proximity thereto; generating, by a non-linear electrical circuit (504) of the security tag, a third signal from the first and second signals applied thereto; ceasing generation of the third signal by the non-linear electrical circuit when at least a first portion (306) of the security tag is moved a certain distance from the detaching unit; and determining by the detaching unit that the first portion of the security tag has been decoupled from a second portion (318) of the security tag when the third signal is no longer being generated by the non-linear electrical circuit.

Claims

1. A method for verifying a detachment of a security tag from an article, comprising:

concurrently producing, by a detaching unit, a first signal at a first frequency and a second signal at a second frequency when the security tag is in proximity to the detaching unit, the detaching unit operative to detach the security tag from the article;

performing operations by a non-linear frequency mixer circuit disposed within the security tag to generate a third signal from mixing the first and second signals applied thereto by the detaching unit, where the non-linear frequency mixer is exclusive of an Electronic Article Surveillance (“

EAS”

) element disposed within the security tag;

ceasing generation of the third signal by the non-linear frequency mixer circuit when a first portion of the security tag is moved a certain distance from the detaching unit; and

determining by the detaching unit that the first portion of the security tag has been decoupled from a second portion of the security tag when the third signal is no longer being generated by the non-linear frequency mixer circuit.

2. The method according to claim 1, wherein the first frequency falls within an Ultra-high frequency band and the second frequency falls within a low frequency band.

3. The method according to claim 1, wherein the first portion of the security tag comprises a pin or the second portion of the security tag comprises a tag body.

4. The method according to claim 1, wherein the second portion of the security tag is still in proximity to the detaching unit when generation of the third signal is ceased.

5. The method according to claim 1, wherein the non-linear frequency mixer circuit comprises a diode or a capacitor placed across two dipole antenna elements.

6. The method according to claim 1, wherein the non-linear frequency mixer circuit comprises a diode or capacitor arranged in parallel with a resonating capacitor of an antenna structure.

7. The method according to claim 1, further comprising verifying a validity of information obtained from the security tag prior to or subsequent to a determination that the first portion of the security tag has been decoupled from the second portion of the security tag.

8. The method according to claim 7, wherein the information comprises a unique identifier for the security tag which was obtained by the detaching unit via RFID communications with an RFID element of the security tag.

9. The method according to claim 7, further comprising completing a purchase transaction of the article when (1) a determination has been made that the first portion of the security tag has been decoupled from the second portion of the security tag, and (2) the validity of the information has been verified.

10. The method according to claim 1, further comprising detecting by the detaching unit when the security tag is in proximity thereto.

11. The method according to claim 10, wherein the first and second signals are generated in response to the detection that the security tag is in proximity to the detaching unit.

12. A system, comprising:

a security tag comprising a non-linear frequency mixer circuit generating a third signal from mixing first and second signals applied thereto by a detaching unit, the first signal having a first frequency and the second signal having a second frequency different from the first frequency; and

said detaching unit determining that a first portion of the security tag has been decoupled from a second portion of the security tag when the third signal is no longer being generated by the non-linear electrical circuit;

wherein the third signal is no longer generated by the non-linear electrical circuit when the first portion of the security tag is moved a certain distance from the detaching unit; and

wherein the non-linear frequency mixer circuit is exclusive of an Electronic Article Surveillance (“

EAS”

) element disposed within the security tag.

13. The system according to claim 12, wherein the first frequency falls within an Ultra-high frequency band and the second frequency falls within a low frequency band.

14. The system according to claim 12, wherein the first portion of the security tag comprises a pin or a tag body.

15. The system according to claim 12, wherein the non-linear frequency mixer circuit comprises a diode or a capacitor placed across two dipole antenna elements.

16. The system according to claim 12, wherein the non-linear frequency mixer circuit comprises a diode or capacitor arranged in parallel with a resonating capacitor of an antenna structure.

17. The system according to claim 12, wherein the detaching unit further performs operations to verify a validity of information obtained from the security tag prior to or subsequent to a determination that the first portion of the security tag has been decoupled from the second portion of the security tag.

18. The system according to claim 17, wherein the information comprises a unique identifier for the security tag which was obtained by the detaching unit via RFID communications with an RFID element of the security tag.

19. The system according to claim 16, wherein a purchase transaction of an article is completed when (1) a determination has been made that the first portion of the security tag has been decoupled from the second portion of the security tag, and (2) the validity of the information has been verified.

20. The system according to claim 12, wherein the first and second signals are applied to the security tag in response to a detection by the detaching unit that the security tag is in proximity thereto.