JP2011186840A - Embedded ic tag - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve a communication distance in the case of embedding an IC tag in a cement composition, and in the case of reading/writing the ID or various information of the IC tag by using an external reading device so that the ID or various information of the IC tag can be easily read before or after the hardening of the cement composition. <P>SOLUTION: This IC tag including an IC tag LSI, an antenna, and a circular sphere-shaped or ellipse sphere-shaped coating body incorporating them is characterized in that the direction of the directivity of the antenna connected to the IC tag LSI is matched with the short axial or long axial direction of the ellipse sphere. The IC tag can be embedded in a concrete, mortar, and cement harding body. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

The present invention relates to an embedded IC tag that is embedded and managed in concrete, mortar, cement admixture or the like.

IC tags are used in quality control and physical distribution management of cement compositions such as concrete, mortar, and cement admixtures.

The IC tag is used for electronic money, entrance / exit management, or attached to an object for traceability and quality control in physical distribution. The IC tag is used for exchanging individual IDs and various information between the IC tag and an external reading device by wireless communication. However, an antenna is required in the IC tag because radio waves are used. Antenna characteristics in wireless communication have directivity and polarization planes in any direction in a three-dimensional space, and are affected by the frequency of radio waves as the high-frequency power supplied to the antenna, the antenna shape, and the surrounding environment. The When directivity is given in a specific direction, gain is obtained in a specific direction, which is advantageous in communication between two points, and the communication distance can be extended. If the gain or the radiation in a direction other than a specific direction is reduced by having the communication distance, the communication distance becomes short and communication becomes difficult.

  In order to deal with such problems, it is usual to increase the efficiency of the antenna, as well as to use the antenna directivity or increase the directivity according to the usage, and to change the antenna according to the directivity. To ensure stable communication.

As for the IC tag, the built-in antenna usually has directivity, so that stable communication is possible in a specific direction. On the other hand, communication may be difficult depending on the direction. Therefore, when using the IC tag, the IC tag is usually held or attached so that the direction of the antenna of the external reading apparatus is directed to the direction of the directivity of the IC tag.
On the other hand, when using an IC tag for concrete quality control, an IC tag having a wide directivity is known (Patent Document 1).

JP 2009-282688 A

When using IC tags that are directional to the cement composition for maintenance, quality control and traceability of concrete, mortar, cement admixture, etc., the cement composition is fluid before curing. If the direction of the IC tag is not fixed, and the IC tag is randomly arranged after curing, it is possible to read and write from a specific direction, but it is expected that communication will be impossible in other directions Is done.

Furthermore, it is possible to suppress the directivity as much as possible by the antenna design, but by making it non-directional in this way, radio waves are radiated in all directions and energy is dispersed, so the communication distance is reduced overall. There is a problem such as.

The present invention solves these problems, and in the case of using an IC tag mixed in a cement composition, it secures a communication distance by using an IC tag having directivity and enables stable communication. is there. The IC tag is embedded in the cement composition, and the reading distance of the IC tag ID and various information is read and written using an external reading device, the communication distance is improved, and the external reading device before or after the cement composition is cured. The problem was to make it easier to read.

An IC tag including an IC tag LSI, an antenna, and a spherical or elliptical spherical covering with these incorporated therein, and the directionality of the antenna connected to the IC tag LSI is made to coincide with the minor axis or major axis direction of the elliptical sphere There are provided an IC tag for embedding concrete, mortar, and hardened cement body.

Provided is the above IC tag, wherein the elliptical sphere has a minor axis / major axis ratio of 0.5 to 1.0.

Provided is an IC tag of the previous period, characterized in that the material of the oval spherical covering material is resin or cement kneaded material, and the position of the center of gravity is on the short axis or long axis of the oval sphere but not in the center To do.

Thus, it is possible to provide an IC tag that includes an antenna having directivity and in which the IC tag faces a specific direction in the cement composition.

Here, the spherical or oval spherical covering may not be a geometrically perfect sphere or ellipsoid. For example, even for a covering including a portion that can be approximated by an actual polyhedron, the maximum length of a line segment obtained by cutting the covering is measured, and is set to a, and the line segment is vertically divided into two equal parts. By measuring the cross-sectional area and the contour line of the covering cut off by the surface and setting them as S and L, respectively, the allowable range can be obtained.

That is, if L is the area S _{0 of} the circle having the circumference, 1 ≧ S / S ₀ ≧ 0.8, and if the diameter of the circle having the area S ₀ is b, 1 ≧ b / a ≧ 0.5 . Such a geometric deformation can be sufficiently used as the covering of the present invention.

Here, the directivity of the antenna indicates the relationship between the radiation direction of radio waves and the radiation intensity, and changes depending on the shape of the antenna and the frequency band used. Usually, as the relationship between the radiation angle and the radiation intensity, for example, if the directivity of the transmitting antenna is used, the direction of the transmitting antenna is changed up and down, left and right, and the decibel (dB) ) As a directivity diagram.

Since the radiation of radio waves is spatial, it usually shows directivity with three-dimensional radiation. However, for example, a case where radio waves are radiated at an angle of 360 ° with respect to a specific surface, such as a dipole antenna, may be non-directional, and an IC tag transmits using received radio wave energy. Therefore, when the directivity of the antenna is shown as radiation intensity, it may not match the actual communicable distance, which is not practical, and there is also a problem that the polarization plane of the radio wave affects.

For these reasons, “directivity” means that “the radio wave generated from the antenna is expressed as a vector with the radiation intensity and direction of the radio wave as a vector, and the source of the radio wave is the starting point of the vector. The curved surface formed at the end point should not be a sphere ”.

In addition, when the “directional antenna” is defined using the maximum reading communication distance between the IC tag and the external reading device with the IC tag connected as an index, the “maximum reading communication with the external reading device in the three-dimensional space” is defined. This is an IC tag antenna whose distance is not uniform, and in the present invention, it is an “IC tag antenna whose ratio between the shortest read communication distance and the longest read communication distance is twice or more”.

Furthermore, the main direction of directivity refers to the direction with the longest reading communication distance.

In the present invention, since the antenna built in the IC tag has directivity in a specific direction, the antenna has a directivity that does not become a non-directional sphere as a whole.

It is installed so that the main direction of the antenna directivity is the axial direction of the elliptic sphere. The antenna itself or an extension line in the main direction of the directivity is arranged so as to pass through the center of the elliptical sphere, and is covered with the elliptical IC tag coating material.

The elliptical sphere has a minor axis / major axis ratio of 0.5 to 1.0 (when the minor axis / major axis ratio is 1.0, it becomes a sphere). When the IC tag is divided into two by a plane passing through the center and including the axis, one semi-elliptical sphere may have a specific gravity difference from the other semi-elliptical sphere. The overall shape is spherical or elliptical. This makes it easy for the IC tag to face the specific direction and the main direction of the antenna directivity to the short axis direction due to the specific gravity difference in the vertical direction easily in the cement composition having fluidity. If the minor axis / major axis ratio is not in the range of 0.5 to 1.0, it becomes difficult for the elliptical sphere to be oriented uniformly by vibration even if the position of the center of gravity is shifted from the center of the elliptical sphere. In this way, the IC tag itself is easily rotated by the vibration of the concrete compaction.

The material of the covering material is resin or cement kneaded material. A metal having a large specific gravity such as stainless steel or a ceramic such as alumina or zirconia may be formed into a semi-elliptical sphere shape in the lower layer portion, and a resin or cement kneaded material may be used in the upper layer. Further, in the lower layer portion, for example, metal particles such as lead particles and stainless particles, ceramic particles such as alumina particles and zirconia particles having a particle diameter of 0.1 mm or more are put in a mold to be molded in advance, or are relatively fluid. An IC tag having a specific gravity difference between the upper and lower layers may be obtained by utilizing the fact that it is mixed with the upper layer material having the property and gathered in the lower layer by its own weight.

As a method for controlling the specific gravity of the material used for the upper and lower layer portions, the specific gravity can be adjusted by mixing aggregates having different specific gravities in a resin or cement kneaded material to obtain an upper layer portion and a lower layer portion. In particular, the cement kneaded material is an effective material because it has excellent adhesion to the cement composition. As the resin, a general resin such as an epoxy resin, an acrylic resin, a polyethylene resin, a polypropylene resin, or a polystyrene resin can be used.

The aggregate preferably has a particle diameter of 0.1 mm to 5 mm. Lightweight aggregate (specific gravity 2.0 or less, artificial lightweight aggregate obtained by artificially firing and foaming expanded shale etc. as raw material, or natural lightweight aggregate such as pumice and volcanic ejecta), Heavy aggregate (specific gravity of 2.5 or higher, desirably 2.8 or higher, naturally produced iron ore or other natural heavy aggregates crushed from rocks, etc., manufactured by melting dust or slag containing a lot of iron) Artificial weight aggregate, ceramic aggregate molded and fired such as alumina), iron powder, stainless steel powder, barium sulfate, tungsten powder, lead powder and lead particles can be used. When the aggregate is metallic, the communication distance of the IC tag may be reduced. Therefore, it is desirable to install the IC tag antenna several millimeters or more away from the metallic so as to reduce the influence.

Further, the specific gravity may be adjusted by adding bubbles such as granular foamed polystyrene and foam mortar to the cement kneaded product.
In addition, in order to manufacture the present invention with the specific gravity difference of the elliptical hemisphere by the present covering material, an IC tag substrate provided with an antenna is installed in an arbitrary direction, and the specific gravity difference is provided using the aggregate. Molded with 2 or more types of materials. Alternatively, in the case of a cement kneaded product, in the cement kneaded product containing heavy aggregate, cement, water, and a water reducing agent, the fluidity may be increased and the specific gravity difference may be adjusted by utilizing the fact that the heavy aggregate settles. . In this case, a thickener may be added to control the sedimentation of the heavy aggregate.

Thus, it is preferable that the specific gravity of the portion which becomes the upper layer portion of the product of the present invention obtained is 2.1 or less and the portion which becomes the lower layer portion exceeds the specific gravity 2.1. Further, the specific gravity difference between the two layer portions is preferably 0.2 or more, more preferably 0.6 or more.

As described above, according to the present invention, it is easy to read from an external reading device before or after the cement composition is cured.

The schematic diagram which shows the external appearance of this invention. The schematic diagram which shows the internal structure of this invention. The schematic diagram which shows the usage example of this invention.

Hereinafter, embodiments of the present invention will be specifically described.
The present invention is an IC tag antenna having directivity in a specific direction, resonates at a half wavelength formed by folding on a substrate, and the main direction of directivity is a donut shape perpendicular to the longitudinal direction of the antenna. A certain thing was used, and cement kneaded material and resin were used as IC tag coating | covering material from which specific gravity differs in an up-and-down part.

The combined shape of the upper layer portion and the lower layer portion was spherical or elliptical. In FIG. 1, the schematic diagram which shows the external appearance of this invention is shown. In the figure, a is the major axis (major axis) of the ellipse, and b is the length of the minor axis (minor axis). In the cement composition having fluidity, the IC tag faces a specific direction due to the specific gravity difference in the vertical direction. The ratio of the major axis to the minor axis was 0.5 to 1. Within this ratio range, the tag itself was easy to rotate, especially due to the vibration of the concrete compaction.

In the material of IC tag covering material Table 1, foam glass beads, natural shirasu balloons, fly ash balloons and epoxy resins are selected as materials with a specific gravity of 2.1 or less of the upper layer part. An example in which zirconia beads, alumina beads, silica sand, and alumina powder were used as the aggregate material having a specific gravity of 2.1 was shown.

In order to control the specific gravity of the material used for the upper and lower layer portions, the specific gravity was adjusted by mixing aggregates having different specific gravities in the resin or cement kneaded material to obtain an upper layer portion and a lower layer portion.

The particle size of each aggregate, the amount of aggregate (parts by weight), the amount of water (parts by weight), the amount of high-performance water reducing agent (parts by weight), and the specific gravity (specific gravity of the molded product after curing) were shown.

The IC tag LSI and IC tag antenna installed in the IC tag were connected in advance, and the IC tag LSI used the 950 MHz band. The IC tag antenna has directivity in the direction perpendicular to the antenna, and it is difficult for radio waves to fly on the extended line of the antenna, making it difficult to communicate with an external reading device. The specific shape of the antenna is shown in FIG. FIG. 3 shows an IC tag in which the main direction of directivity of the IC tag antenna is matched with the major axis direction of the elliptic sphere.

The IC tag LSI and the IC tag antenna were previously thinly coated with a silicone resin in order to prevent damage when forming the upper layer portion and the lower layer portion.

Table 1 shows materials used for the upper layer portion and the lower layer portion. The upper layer portion and the lower layer portion were manufactured according to the formulation shown in Table 1, and the IC tag LSI and the IC tag antenna were embedded in the vertical direction. In this embodiment, the purpose is to read from the wall surface of the concrete as the cement composition, so that it was installed in the vertical direction. Embedded in the direction (Fig. 2).

For production, a resin ice tray for making spherical ice with a diameter of 4 cm was used. IC tag numbers I to X are set in the vertical direction of the IC tag LSI and IC tag antenna (total length: about 35 mm) that are pre-connected and silicone-coated. Half the amount was poured, and after about 2 hours, the lower layer portion having a different specific gravity was poured, and after curing, the frame was removed to produce a spherical IC tag.

IC tag numbers XI and XII are molded by placing alumina or stainless steel balls of one-third of the total volume in an ice tray and then pouring only the upper layer. At this time, vibration was applied so that the upper layer material could enter between the balls. IC tag number XIII is 1/3 the size of a sphere with a diameter of 4 cm, and the IC tag LSI and IC tag antenna were set using ceramics molded and sintered so that the IC tag antenna could be inserted into the center. Later, similarly, the upper layer part was poured using an ice tray.

Each of the five IC tags manufactured in this way is used, and it is kneaded into approximately 5 liters of normal concrete with a slump of 8 cm and a blended design strength of 24 N / mm ^{2 by using} a scoop and molded into a cylindrical test specimen with a concrete φ15 cm height of 30 cm. did. At the time of molding, it was placed in three layers using a rod-like vibrator, and was further subjected to vibration for about 3 minutes by a concrete form vibrator. After the concrete was cured, it was cured for one week, and the number of IC tags that could be read was counted from the side of the concrete specimen using an external reading device. The results are shown in Table-2. Table 2 shows the manufactured IC tag and the reading rate in concrete burial.

In the example, four or more of the five IC tags could be read, whereas in the comparative example, it was two to three.

Claims (3)

IC tag LSI, an antenna, and an IC tag including a spherical or elliptical spherical covering containing these, and the main direction of antenna directivity connected to the IC tag LSI coincides with the minor axis or major axis direction of the elliptical sphere IC tag for embedding concrete, mortar, cement hardened body, characterized by 2. The IC tag according to claim 1, wherein a short axis / long axis ratio of the circular sphere or the elliptic sphere is 0.5 to 1.0. The material of the circular sphere or elliptical spherical covering material is resin or cement kneaded material, and the position of the center of gravity is on the short axis or long axis of the circular sphere or elliptical sphere, and is not in the center thereof. IC tag from the previous term.