Radio frequency IC tag and bolt with an IC tag

• US 20060022056A1
• Filed: 12/14/2004
• Published: 02/02/2006
• Est. Priority Date: 07/28/2004
• Status: Active Grant

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Sakama, Isao, Ashizawa, Minoru
• Granted Patent: US 7,256,697 B2
• Time in Patent Office: Days
• US Class Current: 235/492
• CPC Class Codes: G06K 19/04 characterised by the shape
• 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 19/07771 the record carrier comprising means for minimising adverse effects on the data communication capability of the record carrier, e.g. minimising Eddy currents induced in a proximate metal or otherwise electromagnetically interfering object

Abstract

A radio frequency IC tag includes an antenna substrate accommodated on a bottom portion of an outer casing and an antenna radiation portion mounted on a surface of the antenna substrate. These parts are encapsulated by a sealing agent. An IC chip is disposed at a substantial center on a backside of the antenna substrate. A ground pattern connected to an electrode terminal of the IC chip is formed in an area, on which the IC chip is not mounted. A through electrode passes through the antenna substrate from its back surface to above its front surface at a position slightly offset from the center thereof. The through electrode is connected to the antenna radiation portion on the front surface and to the electrode terminal of the IC chip on the back surface.

Claims

1. A radio frequency IC tag including an IC chip for storing information and an antenna for transmitting wirelessly the information stored on the IC chip, the radio frequency IC tag comprising:

an antenna substrate, on a first surface of which the IC chip is mounted at a substantial center of the first surface, and which has a ground pattern formed over a remainder of the first surface and electrically connected to a first electrode terminal of the IC chip, the antenna substrate having a predetermined dielectric constant;

an antenna radiation portion mounted on a second surface of the antenna substrate and electrically connected to a second electrode terminal of the IC chip; and

an outer casing accommodating therein the antenna substrate and the antenna radiation portion.

2. The radio frequency IC tag according to claim 1,

wherein the outer casing has an cylindrical outer surface or a threaded outer surface.

3. The radio frequency IC tag according to claim 2,

wherein the antenna radiation portion is formed into a cylindrical column having a diameter set to λ

/2 when a wavelength of a radio wave to be used on the antenna substrate is λ and

a head of the cylindrical column of the antenna radiation portion is substantially flush with an upper edge of the outer casing.

4. The radio frequency IC tag according to claim 3,

wherein the diameter of the antenna radiation portion is established based on the dielectric constant of the antenna substrate.

5. The radio frequency IC tag according to claim 3,

wherein a height of the antenna radiation portion is set according to a machining margin of a controlled material on which the radio frequency IC tag is mounted.

8. The radio frequency IC tag according to claim 1,

wherein a through electrode penetrates through the antenna substrate, extending from the first surface to above the second surface of the antenna substrate, the second electrode terminal of the IC chip being connected to the antenna radiation portion by the through electrode.

9. The radio frequency IC tag according to claim 8,

wherein the through electrode is disposed offset from a center of the antenna radiation portion to achieve impedance matching.

6. A bolt with an IC tag including an IC chip for storing information and an antenna for transmitting wirelessly the information stored on the IC chip,

wherein a hole adapted to receive the radio frequency IC tag is formed in a head of the bolt and the radio frequency IC tag is received in the hole.

7. The bolt with an IC tag according to claim 6,

wherein the antenna includes a disk disposed at a position corresponding to a surface of the head of the bolt, a connection wire is extended from a center of the disk and connected to an electrode terminal of the IC chip, a distance between the disk and the electrode terminal of the IC chip is set to λ

/4 when a wavelength of a radio wave to be used on an antenna substrate is λ

, and the antenna constitutes a monopole antenna.

10. A radio frequency IC tag including an IC chip for storing information and an antenna for transmitting wirelessly the information stored on the IC chip, the radio frequency IC tag comprising:

an antenna substrate having a predetermined dielectric constant, said substrate having the IC chip mounted on a first surface thereof, and having a ground pattern formed over a portion of the first surface, said ground pattern being electrically connected to a first electrode terminal of the IC chip;

an antenna radiation portion mounted on a second surface of the antenna substrate and electrically connected to a second electrode terminal of the IC chip; and

an outer casing accommodating therein the antenna substrate and the antenna radiation portion.

11. The radio frequency IC tag according to claim 10,

wherein the outer casing has an cylindrical outer surface or a threaded outer surface.

12. The radio frequency IC tag according to claim 11,

wherein the antenna radiation portion is formed into a cylindrical column having a diameter set to λ

/2 when a wavelength of a radio wave to be used on the antenna substrate is λ and

a head of the cylindrical column of the antenna radiation portion is substantially flush with an upper edge of the outer casing.

13. The radio frequency IC tag according to claim 12,

wherein the diameter of the antenna radiation portion is established based on the dielectric constant of the antenna substrate.

14. The radio frequency IC tag according to claim 12,

wherein a height of the antenna radiation portion is set according to a machining margin of a controlled material on which the radio frequency IC tag is mounted.

15. The radio frequency IC tag according to claim 10,

wherein a sealing agent is injected into the casing for sealing the radio frequency IC tag.

16. The radio frequency IC tag according to claim 10,

wherein support members are included for controlling a height of the antenna substrate relative to a bottom portion of the outer casing.

17. The radio frequency IC tag according to claim 10,

wherein a through electrode penetrates through the antenna substrate, extending from the first surface to above the second surface of the antenna substrate, the second electrode terminal of the IC chip being connected to the antenna radiation portion by the through electrode.

18. The radio frequency IC tag according to claim 17,

wherein the through electrode is disposed offset from a center of the antenna radiation portion to achieve impedance matching.