Apparatus for identifying an article

• US 6,346,884 B1
• Filed: 03/23/2000
• Issued: 02/12/2002
• Est. Priority Date: 09/25/1998
• Status: Expired due to Fees

• Current Assignee: Mitsubishi Materials Corporation
• Original Assignee: Mitsubishi Materials Corporation
• Inventors: Ishihara, Osamu, Uozumi, Gakuji
• Primary Examiner(s): Hofsass, Jeffery
• Assistant Examiner(s): NGUYEN, HUNG T
• Application Number:
  US09/533,935
• Time in Patent Office: 691 Days
• Field of Search: 340/572, 340/825.3, 340/825.54, 340/988, 340/572.4, 340/572.5, 455/73, 455/106, 455/85, 455/86, 455/88
• US Class Current: 340/572.1
• CPC Class Codes: G06K 19/07796 arrangements on the record carrier to allow stacking of a plurality of similar record carriers, e.g. to avoid interference between the non-contact communication of the plurality of record carriers
• CPC Class Codes: G06K 7/0008 General problems related to the reading of electronic memory record carriers, independent of its reading method, e.g. power transfer

Abstract

An apparatus for identifying an article including an interrogator to enable a tag to be identified, even if the tag is overlapped with another tag or a metal plate. The tag is attached to the article, and a memory for storing data about the article is provided in an RFID element connected to an antenna coil of the tag. The tag is activated by transmitting a radio wave of a frequency with which the tag resonates from a transmitting/receiving antenna of the interrogator. Data is read from the memory in response to a reading command, and data is writing into the memory in response to a writing command from the interrogator. The interrogator also includes an oscillation circuit for sweeping a radio wave transmitted from the transmitting/receiving antenna over a predetermined frequency range. The predetermined frequency range is a frequency range which includes all resonance frequencies of a plurality of the tags that vary based on plurality of overlapped articles to which the tags are attached.

Claims

1. An apparatus for identifying an article, comprising:

at least one tag configured to be attached to the article and having an antenna coil and a RFID element connected to the antenna coil; and

an interrogator configured to activate the tag by transmitting a radio wave with which the at least one tag resonates from a transmitting/receiving antenna, and configured to read and write data about the article to and from a memory of the RFID element,

wherein the interrogator includes an oscillation circuit configured to sweep the radio wave transmitted from said transmitting/receiving antenna over a first predetermined frequency range including each resonant frequency of the at least one tag attached to a plurality of overlapped articles, and

wherein the first predetermined range of frequencies includes a resonance frequency of each tag which varies based on a mutual inductance occurring between the antenna coils of overlapped tags.

2. The apparatus according to claim 1, further comprising:

a metal object attached to the article,

wherein the oscillation circuit sweeps the radio wave over a second predetermined frequency range including each resonant frequency of the at least one tag attached to a plurality of overlapped articles having the metal object.

3. The apparatus according to claim 2, wherein the second predetermined range of frequencies includes a resonance frequency of each tag which varies based on a mutual inductance between the antenna coils of overlapped tags and the metal object.

4. A method of identifying an article, comprising:

attaching to the article a tag having an antenna coil and a RFID element connected to the antenna coil;

activating the tag by transmitting a radio wave with which the at least one tag resonates from a transmitting/receiving antenna;

reading and writing data about the article to and from a memory of the RFID element; and

sweeping the radio wave transmitted from said transmitting/receiving antenna over a first predetermined frequency range including each resonant frequency of the at least one tag attached to a plurality of overlapped articles, and

wherein the first predetermined range of frequencies includes a resonance frequency of each tag which varies based on a mutual inductance occurring between the antenna coils of overlapped tags.

5. The method according to claim 4, wherein the sweeping step sweeps the radio wave over a second predetermined frequency range including each resonant frequency of the at least one tag attached to a plurality of overlapped articles having at least one metal object.

6. The method according to claim 5, wherein the second predetermined range of frequencies includes a resonance frequency of each tag which varies based on a mutual inductance between the antenna coils of overlapped tags and the at least one metal object.

7. A system for identifying an article, comprising:

means for attaching to the article a tag having an antenna coil and a RFID element connected to the antenna coil;

means for activating the tag by transmitting a radio wave with which the at least one tag resonates from a transmitting/receiving antenna;

means for reading and writing data about the article to and from a memory of the RFID element; and

means for sweeping the radio wave transmitted from said transmitting/receiving antenna over a first predetermined frequency range including each resonant frequency of the at least one tag attached to a plurality of overlapped articles,

wherein the first predetermined range of frequencies includes a resonance frequency of each tag which varies based on a mutual inductance occurring between the antenna coils of overlapped tags.

8. The system according to claim 7, wherein the sweeping means sweeps the radio wave over a second predetermined frequency range including each resonant frequency of the at least one tag attached to a plurality of overlapped articles having at least one metal object.

9. The system according to claim 8, wherein the second predetermined range of frequencies includes a resonance frequency of each tag which varies based on a mutual inductance between the antenna coils of overlapped tags and the at least one metal object.