Apparatus for detecting theft by a radio wave

• US 6,304,182 B1
• Filed: 12/24/1998
• Issued: 10/16/2001
• Est. Priority Date: 12/25/1997
• Status: Expired due to Fees

• Current Assignee: Mitsubishi Materials Corporation
• Original Assignee: Mitsubishi Materials Corporation
• Inventors: Yonezawa, Tadashi, Miyake, Masami, Mori, Tomohiro, Ishiyama, Kouichi, Endo, Takanori, Osawa, Shigeyuki, Yahata, Seiro
• Primary Examiner(s): TONG, NINA C
• Application Number:
  US09/220,443
• Time in Patent Office: 1,027 Days
• Field of Search: 340/572.1, 340/570, 340/569, 340/571, 340/572.2, 340/572.4, 340/572.5, 340/572.6, 340/572.7, 340/572.8, 340/568.1, 340/568.6, 340/568.7, 340/568.8, 340/545.6
• US Class Current: 340/572.1
• CPC Class Codes: G08B 13/2414 using inductive tags
• CPC Class Codes: G08B 13/2477 Antenna or antenna activator circuit
• CPC Class Codes: G08B 13/248 EAS system combined with another detection technology, e.g. dual EAS and video or other presence detection system

Abstract

A burglar detection apparatus has a tag 11 that includes a resonance circuit. The tag is preferably contained with an object 15 whose theft is desired to be detected. The tagged object may be placed in a drawer 14 which is contained in a box 13. A tag detection sensor 16 is installed in the box and detects whether the tag 11 is present in the drawer 14. Also, a drawer sensor 17 detects whether the drawer is opened. Based on respective detection outputs of the tag detection sensor 16 and the drawer sensor 17, a control circuit 19 controls an alarm 18. Advantageously, the apparatus can be installed in a comparatively small space, does not malfunction even if subjected to large amounts of electrical noise, and reliably detects the presence or absence of a tag even if the tag is located near a metal object.

Claims

1. A burglar detection apparatus for detecting theft of an object contained in a box having a drawer, the apparatus comprising:

a tag including a resonance circuit, adapted to be associated with the object;

a tag detection sensor configured to detect whether the tag is in the drawer, and to provide a tag detection output;

a drawer sensor configured to detect whether the drawer is open, and to provide a drawer sensor output; and

a control circuit configured to control an alarm based on the tag detection output and the drawer sensor output.

2. The apparatus of claim 1, wherein the tag and the object are configured as one piece in the drawer.

3. The apparatus of claim 1, wherein the drawer is made of metal and the apparatus further comprises:

a soft magnetic member sandwiched between the tag and the drawer.

4. The apparatus of claim 3, wherein the soft magnetic member is made of a material selected from the group consisting of:

a sintered ferrite,

a compact of ferrite powder or binder, and

a composite material of soft magnetic metal powder.

5. The apparatus of claim 1, wherein the tag detection sensor includes:

a loop antenna having a surface, not facing the tag, that is covered by at least one of a wave absorber and an electromagnetic wave shielding member.

6. The apparatus of claim 1, wherein the tag detection sensor includes:

a ferrite core,

a coil that is wound around the ferrite core, and

at least one of a wave absorber and an electromagnetic wave shielding member configured to cover at least a part of the core that does not face the tag.

7. The apparatus of claim 6, further comprising:

a pair of ferrite arms provided at respective ends of the core and protruding toward the tag.

8. The apparatus of claim 1, further comprising:

a self-operation management circuit configured to detect abnormal operation of at least one of the tag, the tag detection sensor, and the drawer sensor.

9. A burglar detection apparatus for detecting theft of an object from a box that has a lid, the apparatus comprising:

a tag including a resonance circuit, adapted to be associated with the object;

a tag detection sensor configured to detect whether the tag is in the box, and to provide a tag detection output;

a lid sensor configured to detect whether the lid is open, and to provide a lid sensor output; and

a control circuit configured to control an alarm based on the tag detection output and the lid sensor output.

10. The apparatus of claim 9, wherein the tag and the object are configured as one piece in the box.

11. The apparatus of claim 9, wherein the box is made of metal, and the apparatus further comprises:

a soft magnetic member sandwiched between the tag and the box.

12. The apparatus of claim 11, wherein the soft magnetic member is made of a material selected from the group consisting of:

a sintered ferrite,

a compact of ferrite powder or binder, and

a composite material of soft magnetic metal powder.

13. The apparatus of claim 9, wherein the tag detection sensor includes:

a loop antenna having a surface, not facing the tag, that is covered by at least one of a wave absorber and an electromagnetic wave shielding member.

14. The apparatus of claim 9, wherein the tag detection sensor includes:

a ferrite core,

a coil that is wound around the ferrite core, and

at least one of a wave absorber and an electromagnetic wave shielding member configured to cover at least a part of the core that does not face the tag.

15. The apparatus of claim 14, further comprising:

a pair of ferrite arms provided at respective ends of the core and protruding toward the tag.

16. The apparatus of claim 9, further comprising:

a self-operation management circuit configured to detect abnormal operation of at least one of the tag, the tag detection sensor, and the lid sensor.

17. A burglar detection apparatus for detecting theft of an object, the apparatus comprising:

a) a tag including a resonance circuit, adapted to be associated with the object;

b) a tag detection sensor configured to detect whether the tag is in a vicinity of the object, and to provide a tag detection output, wherein the tag detection sensor includes;

1) a ferrite core,

2) a coil that is wound around the ferrite core, and

3) at least one of a wave absorber and an electromagnetic wave shielding member configured to cover at least a part of the core that does not face the tag; and

c) a control circuit configured to control an alarm based on the tag detection output.

18. The apparatus of claim 17, further comprising:

a pair of ferrite arms provided at respective ends of the core and protruding toward the tag.

19. The apparatus of claim 18, further comprising:

a self-operation management circuit configured to detect abnormal operation of at least one of the tag and the tag detection sensor.

20. The apparatus of claim 17, further comprising:

a self-operation management circuit configured to detect abnormal operation of at least one of the tag and the tag detection sensor.

21. A burglar detection apparatus for detecting theft of an object, the apparatus comprising:

a) a tag including a resonance circuit, adapted to be associated with the object;

b) a tag detection sensor configured to detect whether the tag is in a vicinity of the object, and to provide a tag detection output, wherein the tag detection sensor includes;

1) a loop antenna having a surface, not facing the tag, that is covered by at least one of a wave absorber and an electromagnetic wave shielding member; and

c) a control circuit configured to control an alarm based on the tag detection output.

22. The apparatus of claim 21, further comprising:

a self-operation management circuit configured to detect abnormal operation of at least one of the tag and the tag detection sensor.