Communications system for an RFID tag having an inductive antenna device detachable or movable

• US 20070069858A1
• Filed: 09/25/2006
• Published: 03/29/2007
• Est. Priority Date: 09/29/2005
• Status: Active Grant

• Current Assignee: OKI Electric Industry Company Limited
• Original Assignee: OKI Electric Industry Company Limited
• Inventors: Kubo, Yuki
• Granted Patent: US 7,460,018 B2
• Time in Patent Office: Days
• US Class Current: 340/10.100
• CPC Class Codes: G06K 19/07749 the record carrier being capable of non-contact communication, e.g. constructional details of the antenna of a non-contact smart card
• CPC Class Codes: G06K 19/07756 the connection being non-galvanic, e.g. capacitive

Abstract

An inductive antenna device intervenes in communication between an RFID tag including an RFID chip and a tag antenna and an RFID access device for accessing the RFID tag. The inductive antenna device includes an access-device-side antenna that is electromagnetically coupled with the antenna of the RFID access device, and a tag-side antenna that is electromagnetically coupled with the tag antenna. The RFID chip and tag antenna in the RFID tag are in an electromagnetically shielded space. The inductive antenna device is attached to the RFID tag or the inductive antenna device is brought in a predetermined position to make communication possible between the RFID tag and RFID access device. An authorized access to the RFID tag is thereby permitted with easy operation with unlimited number of access times, and an illegal leak of the tag information is prevented with a low cost configuration.

Claims

1. An RFID (Radio Frequency IDentification) tag comprising:

an RFID chip;

a tag antenna connected to said RFID chip;

an electromagnetic shield for forming a space including said RFID chip and said tag antenna into an electromagnetically shielded space; and

a positional-relationship controller for providing a first positional relationship and a second positional relationship as a relative positional relationship between an inductive antenna device and said RFID tag, said inductive antenna device including an access-device-side antenna capable of being electromagnetically coupled with an antenna of an RFID access device, a tag-side antenna capable of being electromagnetically coupled with said tag antenna and a conductive line for electrically connecting said access-device-side antenna with said tag-side antenna,

said first positional relationship making possible electromagnetic coupling between said tag antenna and said tag-side antenna staying in said electromagnetically shielded space with said access-device-side antenna positioning outside said electromagnetically shielded space,

said second positional relationship making impossible electromagnetic coupling between said tag antenna and said tag-side antenna.

2. The RFID tag in accordance with claim 1, wherein

said first positional relationship controlled by said positional-relationship controller is a positional relationship in which said inductive antenna device is attached to said RFID tag, and

said second positional relationship is a positional relationship in which said inductive antenna device is spaced apart from said RFID tag.

3. The RFID tag in accordance with claim 1, wherein said inductive antenna device is attached to said RFID tag movably relative to each other between said first positional relationship and said second positional relationship.

4. The RFID tag in accordance with claim 1, further comprising an additional RFID chip and an additional tag antenna which are a same as said RFID chip and said tag antenna, respectively, to form a set,

said positional-relationship controller being operative to said inductive antenna devices.

5. An RFID (Radio Frequency IDentification) tag communications system comprising:

an RFID tag including an RFID chip and a tag antenna connected to said RFID chip;

an RFID access device for activating wireless communication for accessing said RFID tag; and

an inductive antenna device including an access-device-side antenna capable of being electromagnetically coupled with an antenna of said RFID access device, a tag-side antenna capable of being electromagnetically coupled with said tag antenna, and a conductive line for electrically connecting said access-device-side antenna and said tag-side antenna,

said RFID tag comprising;

an electromagnetic shield for forming a space including said RFID chip and said tag antenna into an electromagnetically shielded space; and

a positional-relationship controller for providing a first positional relationship and a second positional relationship as a relative positional relationship between said inductive antenna device and said RFID tag,

said first positional relationship making possible electromagnetic coupling between said tag antenna and said tag-side antenna staying in said electromagnetically shielded space with said access-device-side antenna positioning outside said electromagnetically shielded space,

said second positional relationship making impossible electromagnetic coupling between said tag antenna and said tag-side antenna.

6. The system in accordance with claim 5, wherein

said first positional relationship controlled by said positional-relationship controller is a positional relationship in which said inductive antenna device is attached to said RFID tag, and

said second positional relationship is a positional relationship in which said inductive antenna device is spaced apart from said RFID tag.

7. The system in accordance with claim 5, wherein said inductive antenna device is attached to said RFID tag movably relative to each other between said first positional relationship and said second positional relationship.

8. The system in accordance with claim 5, wherein said RFID tag further comprises an additional RFID chip and an additional tag antenna which are a same as said RFID chip and said tag antenna, respectively, to form a set, said positional-relationship controller being operative to said inductive antenna devices.

9. An inductive antenna device intervening in communication between an RFID (Radio Frequency IDentification) tag including an RFID-chip and a tag antenna connected to the RFID chip and an RFID access device for activating wireless communication for accessing the RFID tag, comprising:

an access-device-side antenna capable of being electromagnetically coupled with an antenna of the RFID access device;

a tag-side antenna capable of being electromagnetically coupled with the tag antenna; and

a conductive line for electrically connecting said access-device-side antenna and said tag-side antenna, a first positional relationship and a second positional relationship being provided as a relative positional relationship of said inductive antenna device to said RFID tag,

said first positional relationship making possible electromagnetic coupling between the tag antenna and said tag-side antenna staying in an electromagnetically shielded space provided in the RFID tag with said access-device-side antenna positioning outside the electromagnetically shielded space,

said second positional relationship making impossible electromagnetic coupling between the tag antenna and said tag-side antenna.