Article management system

• US 9,721,130 B2
• Filed: 03/14/2013
• Issued: 08/01/2017
• Est. Priority Date: 09/14/2012
• Status: Active Grant

• Current Assignee: NEC Corporation
• Original Assignee: NEC Corporation
• Inventors: Ohashi, Keishi, Hattori, Wataru
• Primary Examiner(s): Nguyen, Nam V
• Application Number:
  US14/427,367
• Publication Number:
  US 20150235066A1
• Time in Patent Office: 1,601 Days
• Field of Search: 3405721, 3405727, 340 101- 105, 340 1326, 705 22, 705 28, 235492, 235493, 235435
• CPC Class Codes: B65G 2203/046 RFID
• CPC Class Codes: G06K 7/10128 the step consisting of detection of the presence of one or more record carriers in the vicinity of the interrogation device
• CPC Class Codes: G06K 7/10316 using at least one antenna particularly designed for interrogating the wireless record carriers antennas in general H01Q1/22
• CPC Class Codes: G06K 7/10415 the interrogation device being fixed in its position, such as an access control device for reading wireless access cards, or a wireless ATM banking machines in general G07F19/00
• CPC Class Codes: G06Q 10/0833 Tracking
• CPC Class Codes: G06Q 10/0875 Itemisation or classification of parts, supplies or services, e.g. bill of materials

Abstract

An article management system according to the present invention includes: a reader antenna (102) including an open-type transmission line terminated in an impedance matched state; an RF tag (104) that is placed at a location that is electromagnetically coupled to the reader antenna (102) and is visible from the reader antenna (102) in a state where a management target article (105) is placed in the vicinity of the RF tag; a management target article arrangement region in which the management target article (105) is placed, the management target article arrangement region being set in a location where the management target article (105) is electromagnetically coupled to a tag antenna of the RF tag (104); and an RFID reader (103) that sends a transmitted signal to the reader antenna (102) and receives a response signal output from the tag antenna via the reader antenna (102).

Claims

1. An article management system comprising:

a reader antenna that comprises an open-type transmission line and transmits and receives a radio signal, the open-type transmission line being terminated in an impedance matched state;

an RF tag that is placed at a location that is electromagnetically coupled to the reader antenna and is visible from the reader antenna in a state where a management target article is placed in the vicinity of the RF tag, the RF tag being placed in such a manner that a positional relationship between the RF tag and the reader antenna is fixed regardless of the presence or absence of the management target article;

a management target article arrangement region in which the management target article is placed, the management target article arrangement region being set in a location where the management target article is electromagnetically coupled to a tag antenna of the RF tag; and

an RFID reader that sends a transmitted signal to the reader antenna and receives a response signal output from the tag antenna via the reader antenna,

wherein the RFID reader detects the presence or absence of the management target article by detecting a change in operating characteristics of the tag antenna due to the presence of the management target article based on a change in intensity or phase of a reflected signal from the RF tag; and

a coupling coefficient k1 between the reader antenna and the tag antenna is a value represented by 10^(−

5)≦

k1≦

10^(−

2).

2. The article management system according to claim 1, wherein

the management target article arrangement region is set in a location where a relationship of L1≦

λ

is satisfied, wherein λ

represents a wavelength of a signal used for communication between the RFID reader and the RF tag, and L1 represents a first distance between the management target article and the tag antenna, and

the RF tag is placed at a location where a relationship of L2≦

λ

is satisfied, wherein L2 represents a second distance that is a line-of-sight distance between the reader antenna and the tag antenna.

3. The article management system according to claim 2, wherein the first distance satisfies a relationship of L1≦

λ

/2π

, wherein π

represents a circular constant.

4. The article management system according to claim 2, wherein the second distance satisfies a relationship of L2≦

λ

/2π

, wherein π

represents a circular constant.

5. The article management system according to claim 2, wherein the first distance and the second distance satisfy a relationship of L2>

L1.

6. The article management system according to claim 1, wherein a coupling coefficient k1 between the reader antenna and the tag antenna is smaller than a coupling coefficient k2 between the management target article and the tag antenna.

7. The article management system according to claim 1, wherein

the reader antenna includes:

a dielectric layer;

a strip conductor formed in a mesh-like manner on a front surface side of the dielectric layer; and

a ground conductor that is formed on a back surface side of the dielectric layer and is connected to the strip conductor via a matched termination resistor, and

an article management plate is provided in such a manner that the RF tag is arranged above the front surface side and the management target article arrangement region is set above the RF tag.

8. The article management system according to claim 1, wherein

the reader antenna includes a dielectric layer, a strip conductor, and a ground conductor connected to the strip conductor via a matched termination resistor,

the strip conductor and the ground conductor are alternately arranged so as to be spaced apart from each other on a front surface side of the dielectric layer, and the ground conductor is arranged on a back surface side of the dielectric layer, and

an article management plate is provided in such a manner that the RF tag is arranged above the strip conductor and the management target article arrangement region is set above the RF tag.

9. The article management system according to claim 1, wherein an article management shelf is provided in such a manner that the reader antenna is arranged on a lateral side of the RF tag;

the RF tag is arranged on the front surface side; and

the management target article arrangement region is set above the RF tag.

10. The article management system according to claim 1, wherein the RFID reader communicates with the RF tag by using a radio signal in a UHF band or a microwave band.