JP2009230491A - Spherical ic tag - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that radio communication characteristics fluctuate depending on an angle formed with a reader/writer, in a spherical IC tag housing at least an IC tag provided with a semiconductor chip and a looped antenna within a hollow spherical container. <P>SOLUTION: The spherical IC tag 10 is provided with a mechanism to rotate a face of the looped antenna 11 in a hollow container 17 so as to form a constant angle with respect to the direction of gravity. In the rotary mechanism, the IC tag having a weight on the bottom face floats at a liquid level of fluid 18 housed in the hollow container 17, and the effect that the liquid level becomes perpendicular to the direction of gravity is used, or a gyro mechanism is used. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an IC tag capable of highly reliable wireless communication, and more particularly to a spherical IC tag.

  An article management system using an RFID (Radio Frequency identification) system that performs identification management of articles using an electromagnetic induction effect based on an alternating magnetic field component of an electromagnetic field is used in many fields. Compared to bar code management that has been frequently used in the past, the amount of data that can be stored is large, and this is superior in that data can be rewritten and added. In this RFID management system, a transponder called an IC tag and a reader / writer that forms a functional pair with the transponder are basic components. The IC tag itself is composed of a semiconductor chip and a loop antenna connected to the semiconductor chip. It is configured.

  The semiconductor chip is responsible for wireless communication control between the reader / writer and data management in the memory. On the other hand, for the loop antenna, the role and information of supplying power induced to the antenna by the alternating magnetic field from the reader / writer to the semiconductor chip. There is a function to send and receive.

  The IC tag having the above basic configuration is used by being embedded in an object of various shapes depending on the application to be used. For example, a planar shape such as a sheet shape, a card shape, a coin shape, or a spherical shape, a key ring There are even three-dimensional shapes such as shapes.

  In particular, a spherical IC tag is housed in a container together with a large number of articles, and is used to record the origin identification and distribution management information of the articles in the container. It is housed and used. By tracing the trajectory of the ball using the wireless communication function of the IC tag, it is used to electronically determine the progress management or victory or defeat of the ball game. In particular, the ball game is rich in diversity. This is a suitable field of application for tags (see, for example, Patent Document 1).

For example, in a plastic golf ball, as shown in FIG. 2 (a), an IC tag including a semiconductor chip 12 at the center and a loop-shaped antenna 11 electrically connected to the center is accommodated. By wirelessly communicating with the reader / writer, for example, the position information of the golf ball and the information of falling into the hole can be acquired via the reader / writer. In addition to golf balls, this method is widely applied to various games such as bowling games and billiard games.
Japanese Patent No. 3925354

  However, in the conventional spherical IC tag shown in FIG. 2A, the loop-shaped antenna 11 is planar mainly for manufacturing reasons, and the wireless communication performance with the reader / writer is not stable. There's a problem. This is because the characteristics of wireless communication with a reader / writer are determined by the amount of magnetic flux through which the alternating magnetic field component of the electromagnetic field radiated from the reader / writer passes through the loop of the loop antenna, which is the distance between the loop antenna and the reader / writer and the antenna. This is because it depends on the angle between the surfaces. When the angle formed varies with time, such as when the ball rotates, the power induced in the loop antenna also varies, and the wireless communication characteristics also vary accordingly.

As a countermeasure against this change in angle, a technique has been disclosed in which the planar loop antenna 11 is made into a three-dimensional antenna twisted like an 8-shape as shown in FIG. 2B (see Patent Document 1). By adopting such a shape, a certain finite angle is guaranteed for the direction of the alternating magnetic field from the reader / writer and the intersection angle of the loop antenna. By this method, there is no troublesomeness of arranging a plurality of antennas inside the spherical body, and a certain improvement has been made regarding the problem of blind spots in wireless communication. There remains a problem that the wireless communication characteristics vary depending on the angle formed.

  The present invention has been made in view of this situation, and the invention of claim 1 is a spherical IC tag in which an IC tag including at least a semiconductor chip and a loop antenna is accommodated inside a hollow spherical container. The tag is a spherical IC tag comprising a mechanism that rotates in the hollow container so that the loop antenna surface of the IC tag is perpendicular to the direction of gravity.

  With this configuration, the loop antenna surface can be rotated inside the spherical container, so that the loop antenna surface can maintain the same posture with respect to the direction of gravity.

  The invention according to claim 2 utilizes the effect that the rotating mechanism is such that an IC tag having a weight on the bottom surface floats on the liquid surface of the liquid contained in the hollow container, and the liquid surface is perpendicular to the direction of gravity. The spherical IC tag according to claim 1, wherein

  The invention according to claim 3 is a spherical IC tag characterized in that the rotating mechanism is a gyro mechanism.

  In the above two inventions, two types of methods for maintaining the posture of the IC tag are selected.

  According to the present invention, the loop antenna surface of the IC tag always takes a constant posture with respect to the direction of gravity due to the action of gravity. By installing a reader / writer in a range suitable for wireless communication in that position, the antenna surface forms the same angle as the reader / writer regardless of how the spherical IC tag is tilted. It becomes possible.

  Hereinafter, an example of an embodiment of the invention will be described with reference to FIGS.

  FIG. 1 (a) schematically shows an example of the internal configuration of a spherical IC tag according to the present invention. The spherical body 17 forms a sealed space made of a plastic molded body or rubber, and about half of its volume is filled with the insulating liquid 18. The semiconductor chip 12 is held near the center of the liquid surface and the loop antenna 11 ( Hereinafter, an IC tag (substrate) on which an antenna is simply formed is shown floating. The insulating liquid 18 is selected from petroleum-based oil, silicone oil, etc. In consideration of the weight and volume of the IC tag, the IC tag can obtain sufficient buoyancy and can move quickly and easily in the sphere. The optimum liquid is determined from the density and viscosity. A weight (not shown) is fixed to the back surface of the IC tag (substrate), and this defines the direction of gravity.

  Since the liquid surface is always perpendicular to the direction of gravity even when the spherical body rotates, the IC tag floats with the surface of the antenna 11 parallel to the liquid surface with the weight facing downward. Become. Therefore, since the antenna surface always maintains a finite intersection angle with the reader / writer, the wireless communication performance does not vary greatly due to rotation.

  A gyro mechanism was adopted as another attitude control method. An example of a gyro mechanism suitable for an IC tag is shown in FIG. This is a combination of two rings that can rotate around the diameter direction as a rotation axis, and is fixed inside the sphere (not shown). It is an angle. The inner first ring 15 is rotatable about the center of the second ring 15 because the ring support bar 16 is movable along the outer ring 14 with the outer second ring 14 as a guide. Further, the first ring 15 can also be rotated about the ring support rod 16 as an axis.

  With this configuration, no matter how the sphere tilts, the IC tag is connected to the weight 19 so that it always acts in the direction of gravity. The surface of the antenna 11 takes the same posture with respect to the direction of gravity. Therefore, the angle of intersection between the antenna 11 surface and the reader / writer is always the same. The angle between the antenna surface and the gravitational direction is generally 90 degrees, but it is not necessarily limited to this.

The cross-sectional perspective view which illustrates typically the internal structure of the spherical IC tag which becomes this invention. (A) A type in which an IC tag is suspended on the liquid surface. (B) An example in which a gyro mechanism is employed. The cross-sectional perspective view which illustrates typically the structure of the conventional spherical IC tag. (A) Planar loop antenna, (b) 8-shaped antenna.

Explanation of symbols

10 ... Spherical IC tag 11... (Loop) antenna 12... Semiconductor chip 13... 8 loop antenna 14. The first ring 16 ... the support rod 17 ... the spherical body 18 ... the liquid 19 ... the weight

Claims (3)

  In a spherical IC tag in which an IC tag including at least a semiconductor chip and a loop antenna is accommodated in a hollow spherical container, the spherical IC tag is configured such that the loop antenna surface of the IC tag forms a certain angle with respect to the direction of gravity. A spherical IC tag comprising a mechanism for rotating in the hollow container.   The rotating mechanism utilizes the effect that an IC tag having a weight on the bottom surface floats on the liquid surface of the liquid contained in the hollow container, and the liquid surface is perpendicular to the direction of gravity. The spherical IC tag according to claim 1.   The spherical IC tag according to claim 1, wherein the rotating mechanism is a gyro mechanism.

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