JP2006270212A - Radio tag - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a radio tag having a satisfactory communication state even if the environment of use is changed. <P>SOLUTION: An antenna 3 having a first form directly joined to the I/O terminal of an IC chip 2 can be separated from an antenna 6 having a second form that cannot be directly joined to the I/O terminal of the IC chip, thus achieving the radio tag that can be managed at the same communication frequency even if the environment is changed. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a wireless tag that has at least one IC chip and an antenna therein and can wirelessly communicate data.

  A wireless tag including an IC chip and an antenna capable of storing information can transmit and receive data to and from a wireless device called an interrogator or a reader via radio waves. Such a wireless tag is disclosed in Patent Document 1, for example. In particular, wireless tags that use 300 MHz or higher as the frequency of radio waves and do not have an internal power source have a long communicable distance with the reader / writer and are relatively inexpensive. Use is being considered. Such a wireless tag having no internal power supply is disclosed in Patent Document 2, for example.

  When the wireless tag does not have a power source for driving the IC, a method of obtaining a voltage by converting a radio wave from the reader / writer into a direct current using a diode or a capacitor inside the IC is used. In addition, when the wireless tag has the above power source, a button-type battery, a film-like battery, a large-capacity capacitor, or the like is used as an IC driving power source.

  Radio waves used for communication between a wireless tag and a reader generally have a smaller propagation loss in the air as the transmission power increases, the communication distance between the wireless tag and the reader increases, and the frequency decreases. Therefore, the communication distance becomes long. However, with regard to the frequency of radio waves that can be used and their output levels, there are regulatory values set for each country, and the frequency and transmission power that provide the maximum effect among the regulatory values set for each country. Is selected, and a communication system between the wireless tag and the reader / writer is designed.

  FIG. 11 is a perspective view showing an example of a conventional wireless tag. A wireless tag 11 is configured by providing a base material 4 formed by forming the antenna 3 and the IC chip 2 on the base material 5 via an adhesive layer 7. This wireless tag 11 communicates using the antenna 3 before the substrate 5 is peeled off, and manages or records the wireless tag 11 by recording or reproducing information on the IC chip 2. 5 parts were peeled and removed, and the adhesive layer 7 was used to affix only the 4 part of the base material to an article to be managed, and used for management of the article.

  In general, a wireless tag is designed as a standard product by designing an antenna so that optimum characteristics can be obtained in a wireless tag alone, that is, in a free space. Therefore, the conventional wireless tag 11 shown in FIG. 11 is designed such that the antenna 3 and the IC chip 2 are impedance matched before the base material 5 is removed. When the base material 5 is peeled off from the wireless tag 11 and the base material 4 portion is pasted and used on an article to be managed formed of a resin having a high dielectric constant, for example, the article is configured. When the impedance of the antenna 3 changes due to the dielectric constant of the resin, impedance mismatching with the IC chip 2 occurs, which may lead to deterioration in reading performance and in some cases such as communication failure.

  Further, even in an article in which a metal is disposed in the vicinity of the pasting location, there is a problem in that interference occurs similarly, the impedance of the antenna 3 changes, and the reading performance is deteriorated.

  Therefore, considering the material of the article to be managed and the usage environment, that is, for example, considering the influence of the dielectric constant of the article and the metal material arranged around it in advance, the wireless tag with the optimized antenna shape is designed. There was also a case. In the case of such a design, in FIG. 11, the wireless tag 11 from which the base material 5 is removed is able to communicate and has good communication performance after being attached to the article to be managed. In the state of the wireless tag 11 provided with the base material 5 before the operation, the impedance of the antenna 3 and the impedance of the IC chip 2 are not matched, and the communication performance is deteriorated.

Japanese Patent No. 2555361 JP 2002-298106 A

  A technical problem of the present invention is to provide a wireless tag having a good communication state even when a use environment changes.

  According to the present invention, there is provided a wireless tag having one or more IC chips and two or more antennas, wherein the antenna is directly joined to an input / output terminal of the IC chip; A wireless tag comprising a second form antenna that is not directly joined to an input / output terminal of an IC chip, wherein the first form antenna and the second form antenna are configured to be separable. It is done.

  According to the present invention, it is possible to obtain a wireless tag characterized in that the antenna of the first form and the antenna of the second form are formed on different base materials.

  The wireless tag of the present invention includes a first form antenna directly joined to an input / output terminal of at least one IC chip and a second form antenna not joined directly to the input / output terminal of the IC chip. The antenna of the first form and the antenna of the second form are each made of a conductive material formed on a base material, and the antenna of the first form and the antenna of the second form are configured to be separable.

  The antenna of the first form and the antenna of the second form may be formed on the same surface or front and back of the same base material, or may be formed on different base materials. When the antenna of the first form and the antenna of the second form are formed on the same base material, it is preferable to provide in advance means that can be easily cut, such as a notch or a perforation, in the base material. In the case where the antenna of the first form and the antenna of the second form are formed on different base materials, an adhesive means such as providing an adhesive layer, or a joining means using a fitting means or separate members between substrates It is preferable to provide a structure that can be easily peeled off or separated as necessary while being configured integrally.

  The IC chip and the antenna of the first form are optimized so that the best characteristics can be obtained when they are attached to the article to be managed, that is, considering the material and conditions of the article to be managed. When the wireless tag is attached to the article, the antenna of the first form is used by separating the antenna of the second form from the wireless tag.

  On the other hand, when configured as described above, the antenna of the first form is not necessarily impedance-matched with the IC chip at the optimum value before being attached to the article to be managed, and the communication performance may not be good. Arise. Therefore, in such a case, the antenna of the second form is formed in the vicinity of the antenna of the first form, and the impedance matching between the IC chip and the whole antenna is the optimum value even when not attached to the managed article. To do. By configuring in this way, the IC chip, the antenna of the first form, and the antenna of the second form cooperate in a state where it is not attached to the article to be managed, and the communication state at a certain distance is improved. A wireless tag that can maintain a good communication state at a fixed distance by removing the antenna of the second form and changing the antenna impedance even in a state of being attached to an article to be managed can get.

  According to the present invention, it is possible to provide a wireless tag that has good communication performance in the same frequency band in any state before and after being attached to an article to be managed.

  The wireless tag according to the present invention has an IC chip, an antenna of a first form electrically connected to the IC chip, and an antenna of a second form not electrically connected to the IC chip. Since the antenna of the first form and the IC chip are attached to the finally managed article and used together, the impedance of the antenna of the first form and the IC chip is matched in the state of being attached to the managed article. To be configured. That is, instead of simply performing impedance matching between the antenna of the first form and the IC chip, the antenna of the first form is configured so as to match impedance with the IC chip in consideration of radio wave interference caused by an article to be managed. To do. Also, for example, at the time of factory shipment or distribution, since it is necessary to maintain a good communication state without being attached to the article to be managed, the composite antenna of the first and second antennas is configured to be impedance matched with the IC chip. .

  The first and second antennas are etched using a conductive material such as copper, aluminum or silver on a substrate made of resin or paper such as glass epoxy substrate, PET (polyethylene terephthalate), polyimide, etc. It is formed by general antenna forming means such as printing. The antenna of the first form is electrically connected to the IC chip by a general mounting technique such as wire bonding or flip chip mounting technique.

  In the case where the antenna of the first form and the antenna of the second form are formed on different base materials, for example, an adhesive or a pressure sensitive adhesive is applied between the base materials to form a single body. It is preferable to provide a pressure-sensitive adhesive layer that can be separated and has an adhesive strength or adhesive strength that can be easily re-adhered to an article such as resin, metal, or paper. Alternatively, the base members may be provided with a concave-convex or hook-like fitting structure, or may be temporarily integrated using a coupling means using another member that does not affect the antenna characteristics such as clips and pins.

  In the case where the antenna of the first form and the antenna of the second form are formed on the same base material, for example, in order to easily separate the antennas of the two forms, a cut, a groove, and a perforation are previously provided. It is preferable to provide it. In addition, the base material on which the antenna of the first form is formed is generally attached to an article to be managed by punching a hole, through a string, provided with an adhesive layer in advance, using a double-sided tape, using an adhesive, etc. It is preferable to affix or attach to articles managed by conventional means.

  The wireless tag according to the present invention is designed in consideration of the material, configuration, and surrounding environment of the article to be managed in advance, but even if it is the same article, depending on the configuration of the article to be managed and the surrounding environment, the radio wave interference condition Therefore, if necessary, it is preferable to specify a position where a part of the wireless tag is attached or attached to the article for use.

  Embodiments of the present invention will be described below with reference to the drawings.

Example 1
1, 2 and 3 are views showing a first embodiment of the present invention. FIG. 1 is a perspective view of the wireless tag of the present invention, FIG. 2 is a front view of the wireless tag 1 shown in FIG. 1, and FIG. 3 is an explanatory diagram of the wireless tag when it is attached to an article to be managed. On the base material 4 made of polyethylene terephthalate (hereinafter referred to as PET), an antenna 3 (hereinafter referred to as antenna 3) of the first form is formed by etching using aluminum as a conductor, and the antenna 3 and the IC chip 2 are formed. Were electrically connected by flip chip mounting means. The wireless tag 1 is delivered to a restaurant after shipment from the factory, and is affixed to an ABS resin tray, which is an article to be managed. The antenna 3 was adjusted and formed so as to match.

  Next, the antenna 6 of the second form (hereinafter referred to as the antenna 6) was formed on the surface of the base material 5 made of PET by etching using aluminum as a conductor as shown in FIG. 1 and FIG. At this time, the antenna 6 is formed so as to be impedance matched with the IC chip 2 when it functions as a composite antenna together with the antenna 3 in the state of the wireless tag 1 shown in FIGS.

  The base material 4 and the base material 5 are integrated with each other on the surfaces where the antenna 3 and the antenna 6 are not formed through an adhesive layer 7 that can be easily peeled off. Created.

  In the state shown in FIG. 1 and FIG. 2, the wireless tag 1 records and reproduces shipping / conveying data to manage delivery, and after the restaurant is delivered, the base material 5 is separated and removed as shown in FIG. Sales management was carried out by attaching to 8 items. In both delivery management and sales management, the communication frequency was 2.45 GHz, and the communication state was very good.

  FIG. 4 shows the impedance characteristics of the IC chip 2. 9a represents the real part of the impedance, and 9b represents the imaginary part of the impedance. The impedance of the IC chip 2 at the communication frequency f0 to be used is 20Ω for the real part 9a and −40Ω for the imaginary part 9b. The antenna of the wireless tag 1 is designed so as to be impedance matched with the IC chip 2. Here, the impedance matching condition is that the antenna impedance becomes a conjugate complex number of the impedance of the IC chip.

  FIG. 5 shows the state of the wireless tag 1, that is, the composite antenna impedance when the antenna 3 and the antenna 6 are combined. The impedance at the communication frequency f0 to be used is 20Ω for the real part 9a and 42Ω for the imaginary part 9b. Compared to the impedance of the IC chip 2 shown in FIG. 4, it can be seen that impedance matching is achieved at the communication frequency f0 used.

  FIG. 6 shows antenna impedance in a state where the wireless tag remaining portion 8 shown in FIG. 3 is affixed to an article to be managed. In this case, although the frequency characteristics are different from those in FIG. 5, the real part 9a is 18Ω and the imaginary part 9b is 45Ω at the communication frequency f0 to be used.

  As a comparative example, a wireless tag 1 having the configuration shown in FIG. The antenna 3 was adjusted so that the impedance matched with the IC chip 2 in a state where the base material 5 was removed from the wireless tag 1.

  FIG. 7 shows impedance characteristics in a state before being attached to an article managed by the wireless tag 11 of the comparative example. At the communication frequency f0 to be used, the real part 9a is 2Ω and the imaginary part 9b is −58Ω, which indicates that the impedance characteristics of the IC chip 2 shown in FIG. The mismatch loss in this case was calculated to be 18 dB, and the communication distance was shortened to 1/8 compared with the case where it was attached to a managed article and used, and a good communication state could not be maintained.

  FIG. 8 is an explanatory diagram showing the effect of the present invention. FIG. 8A shows the communication distance 14 between the wireless tag 1 and the reader / writer 12 before the substrate 5 is removed according to the first embodiment. FIG. 8B shows the communication distance 15 in a state where the wireless tag remaining portion 8 after the substrate 5 is removed is attached to the article 10 to be managed. It can be seen that the communication distance 14 and the communication distance 15 are substantially equal. FIG. 9 is a diagram illustrating the communication distance by the wireless tag 11 of the comparative example. Since the wireless tag 11 optimizes the antenna in accordance with the article to be managed, as shown in FIG. 9, the communication distance 14 in FIG. The communication distance 16 is extremely short as compared with FIG.

(Example 2)
FIG. 10 is a perspective view showing a second embodiment of the present invention. On the substrate 4 made of glass epoxy, the first form of the antenna 3 (hereinafter referred to as the antenna 3) is formed by printing using copper paste as a conductor, and is electrically connected to the IC chip 2 by wire bonding. did. The wireless tag 1 is delivered to a musical instrument store after being shipped from the factory, and is attached to a music compact disc (hereinafter referred to as a CD) case, which is an article to be managed. The antenna 3 was adjusted and formed so that the impedance matched with the IC chip 2 even when radio wave interference was caused by a certain polystyrene resin and an aluminum thin film deposited on the CD surface.

  Next, an antenna 6 (hereinafter referred to as antenna 6) of a second form in which copper paste was printed as a conductor on the base material 4 was formed as shown in FIG. At this time, the antenna 6 was formed so as to be impedance-matched with the IC chip 2 when it functions as a composite antenna together with the antenna 3 in the state of the wireless tag 1 shown in FIG.

  In the state shown in FIG. 10, the wireless tag 1 records and reproduces shipping / conveying data and manages delivery, and forms the base material portion and the antenna 6 formed by forming the antenna 3 at the perforation 13 after delivery to the musical instrument store. The base material portion thus formed was separated, and only the base material portion formed with the antenna 3 was attached to a CD case using a double-sided tape for sales management. In both delivery management and sales management, the communication frequency was 950 MHz, and the communication state was very good.

  The embodiments of the present invention have been described above by way of examples. However, the present invention is not limited to these embodiments, and the present invention can be applied even if there is a design change without departing from the gist of the present invention. included. That is, for example, various modifications and corrections that would be obvious to those skilled in the art, such as printing a logo or a cautionary note with conductive ink and using it as an antenna of the second form, are also possible. Of course, it is included in the present invention.

  By using the wireless tag of the present invention, in the management of various articles represented by distribution management, sales management, inventory management, usage status management of goods, etc., a system suitable for the material and usage environment of the articles to be managed, etc. It can be constructed easily.

1 is a perspective view illustrating a wireless tag according to an embodiment of the present invention. 1 is a front view showing a wireless tag according to an embodiment of the present invention. It is explanatory drawing which shows the use condition of the wireless tag by the Example of this invention. It is a figure which shows the impedance characteristic of the IC chip used for the Example of this invention. It is a figure which shows the impedance characteristic of the antenna by the Example of this invention. It is a figure which shows the impedance characteristic of the antenna by the Example of this invention, and shows the characteristic of the state affixed on the articles | goods to manage. It is a figure which shows the impedance characteristic of the antenna of a comparative example. 8A and 8B are diagrams for explaining the effect of the embodiment of the present invention. FIG. 8A shows a state before being attached to an article, and FIG. 8B shows a state after being attached to the article. It is a figure explaining the communication distance of a comparative example, and shows the state before sticking to an article. 1 is a perspective view illustrating a wireless tag according to an embodiment of the present invention. It is a perspective view which shows the conventional wireless tag.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,11 Radio tag 2 IC chip 3 First form antenna 4,5 Base material 6 Second form antenna 7 Adhesive layer 8 Wireless tag remaining part 9a Impedance real part 9b Impedance imaginary part 10 Managed article 12 Reader Writer 13 Perforation 14, 15, 16 Communication distance

Claims (2)

  A wireless tag having one or more IC chips and two or more antennas, wherein the antenna includes a first-type antenna directly joined to an input / output terminal of the IC chip, and an input / output terminal of the IC chip A wireless tag comprising a second form antenna that is not directly joined to the antenna, wherein the first form antenna and the second form antenna are configured to be separable.   The wireless tag according to claim 1, wherein the antenna of the first form and the antenna of the second form are formed on different base materials.

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