JP2007158974A - Electronic tag device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electronic tag device useful for stable communication, by reducing the influences due to inclination of product items as object of management, multi-path generated in the radio signal and height in the product items as the object of management. <P>SOLUTION: The electronic tag device 10 forms storage units 10a, 10b for storing at least one of electronic tags 12, 13 having the function to hold an individual identifying information, previously assigned to own station and to transmit a radio signal that contains individual body identifying information. In this case, a support mechanism is provided, wherein a fulcrum 11 as an axis or a point supported by a product item, such as knapsack, is formed at the position deviated from the gravity center 14 so as to permit free swinging thereof around the fulcrum 11 and also to permit free swinging of the electronic tag devices 12, 13 stored in the storing units 10a, 10b for the product item. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an electronic tag device that stores at least one electronic tag having a function of holding individual identification information assigned in advance to a local station and transmitting a radio signal including the individual identification information.

  For example, an electronic tag is used for individually managing articles such as various commodities or for the purpose of individually managing the passage of people or animals. One typical example of such an electronic tag is a tag that communicates individual identification information using electromagnetic waves, and is called RFID (Radio Frequency Identification). The RFID has a function of holding individual identification information assigned individually and transmitting a radio signal including the individual identification information.

  As types of RFID, there are an active tag incorporating a battery as a power source, for example, and a passive tag that does not require a battery as a power source. The passive tag is a power source necessary for the electronic tag itself to operate by converting the magnetic field energy of an electromagnetic wave transmitted from a reader or reader / writer (hereinafter simply referred to as a reader / writer) that is a device that reads the passive tag into electric power. To get the power.

  In general, both circularly polarized waves and linearly polarized waves are used for the polarization of electromagnetic waves used by the passive tag type RFID for wireless communication. In the case of using circularly polarized waves, as shown in FIG. 4, the electric field and magnetic field of the electromagnetic wave transmitted from the circularly polarized RFID antenna 100a propagate while rotating so as to draw a circle. Therefore, even when the orientation of the antenna 101 of the electronic tag changes in the polarization rotation direction, communication can be performed without any problem. However, with circularly polarized waves, the degree of attenuation of the electromagnetic wave with respect to the electromagnetic wave propagation distance is large. Therefore, the use of passive tag type RFID is limited to communication at a relatively short distance.

  In the case of linear polarization, as shown in FIG. 5, the electromagnetic wave transmitted from the linearly polarized RFID antenna 100b propagates without changing the direction of the electric field and magnetic field of the electromagnetic wave. With linearly polarized waves, the degree of attenuation of electromagnetic waves with respect to distance is small, and communication with a longer propagation distance than circularly polarized waves is possible. However, in the case of linear polarization, in order to be able to communicate in an optimum state, it is necessary to arrange the RFID antenna 100b so that the direction of the RFID tag antenna 100b and the direction of the antenna 101 of the electronic tag are the same.

For example, Patent Document 1 discloses a related art related to the present invention.
JP 2004-86394 A

  As described above, when communication is performed using linearly polarized waves as shown in FIG. 5, the antenna direction of the electronic tag must be matched with the antenna direction of the reader / writer that is the communication partner station. Communication performance decreases and communication becomes difficult. However, various articles and people that are actually managed with electronic tags attached thereto, such as various products and school bags used by school children, do not always have a fixed orientation when moving. Therefore, when the article is tilted and the electronic tag is tilted, the communication performance deteriorates due to the mismatch between the antenna polarization planes on the transmission side and the reception side, and information on the electronic tag cannot be read.

  In an actual use environment, for example, as shown in FIG. 6, there are various reflectors 102 a and 102 b such as a wall of a building around the electronic tag. Therefore, the reader / writer antenna 100 and the electronic tag antenna 101 A radio signal transmitted between the signals propagates through a plurality of propagation paths P1 and P2. Therefore, the effect of so-called multipath appears in which electromagnetic waves propagating through the respective propagation paths interfere with each other. Specifically, as shown in FIG. 7, local attenuation and fluctuation appear due to the multipath of the propagation paths P1 and P2 in the magnetic field intensity distribution according to the distance from the reader / writer transmission antenna. That is, at each null point (received electromagnetic field strength, for example, within a specific range in the x, y, and z directions where the magnetic field strength is below a predetermined reception limit threshold value), the magnetic field strength is significantly reduced. Therefore, for example, when a passive tag type electronic tag exists within the range of the null point, the electronic tag cannot obtain the power required for its own operation and cannot communicate.

  In addition, when an article or the like is managed using an electronic tag and a reader / writer, it is often assumed that the electronic tag and the reader / writer exist at the same height, that is, in the same horizontal plane. However, in the actual use environment, the position of the articles to be managed changes as necessary. For example, as shown in FIG. 8, the electronic tag (passive tag 12 and active tag 13) and the passive tag antenna 100c of the reader / writer are used. It is also assumed that the active tag antenna 100d and the active tag antenna 100d are arranged at positions with greatly different heights.

  The influence of the difference in height between the electronic tag and the reader / writer appears as a change in magnetic field strength as shown in FIG. That is, the magnetic field strength decreases as the difference in height increases. In particular, in the case of a passive tag type electronic tag, the magnetic field strength is significantly reduced as compared with the active tag. Generally, the frequency (for example, 900 MHz) of the electromagnetic wave used for the passive tag is higher than the frequency (for example, 400 MHz) of the electromagnetic wave used for the active tag. Therefore, the electromagnetic wave of the passive tag increases as the height (distance) increases. One factor is that it is more easily attenuated than electromagnetic waves of active tags. Therefore, particularly when a passive tag type electronic tag is used, there is a high possibility that communication is not possible if an article or the like to which the electronic tag is attached is at a low position.

  It is an object of the present invention to provide an electronic tag device that is useful for stable communication by reducing the influence of the inclination of an article to be managed, the influence of multipath generated in a radio signal, and the influence of the height of the article to be managed. Objective.

  The present invention is an electronic tag device that stores at least one electronic tag that stores pre-assigned individual identification information and transmits a wireless signal including the individual identification information, and is biased from the center of gravity of the electronic tag device. At the shifted position, there is a fulcrum supported by an external member, and when the center of gravity is below the fulcrum, the electronic tag is placed above the center of gravity, and the fulcrum swings around the fulcrum. It is possible to move.

  In the present invention, the electronic tag device is supported by the article to be managed in a swingable manner around a fulcrum formed at a position shifted from the center of gravity. Therefore, if the article is stationary, the position of the center of gravity of the electronic tag device is always located below the fulcrum. Therefore, even if the article is inclined with respect to the reference state, the orientation of the electronic tag device with respect to the horizontal plane Is held constant. Accordingly, the orientation of the electronic tag stored in the storage portion of the electronic tag storage case with respect to the horizontal plane is also constant. Therefore, the polarization plane of the reader / writer antenna and the polarization plane of the electronic tag antenna can be matched regardless of the inclination of the article, and a good communication state can be maintained.

  In addition, the electronic device over a range exceeding the distance range on the transmission path, which is caused by mutual interference between the external signal having an electronic tag reading function and the radio signal passing through a plurality of transmission paths, is impossible. The tag can be configured to have a distance between the fulcrum and the electronic tag that can swing.

  As described above, when an electronic tag is present within the range of the null point caused by the multipath effect, the magnetic field strength is significantly reduced, making communication difficult. Here, it is assumed that acceleration is applied to a member or the like to which the electronic tag device is attached by movement or the like. Due to the influence of the acceleration, the electronic tag storage case and the stored electronic tag swing around the fulcrum. In the present invention, the range in which the electronic tag moves due to this swinging is determined to exceed the distance (Δx) corresponding to the null point range. Therefore, even if an electronic tag exists within the null point range, the oscillation occurs when acceleration is applied, and the electronic tag temporarily goes out of the null point range, so communication is performed at that timing. Is possible.

  When the first electronic tag and the second electronic tag having a weight greater than that of the first electronic tag have the center of gravity below the fulcrum, the first electronic tag is provided with at least two electronic tags. The electronic tag device may be configured such that the electronic tag is disposed above the second electronic tag.

  That is, here, it is assumed that a plurality of different types of electronic tags are stored in one electronic tag storage case. For example, in a certain management system, in order to manage one article, a first electronic tag with a narrow communication range (short distance) and a second electronic tag with a relatively wide communication range are required at the same time. And Therefore, as described above, the first electronic tag that is light in weight is disposed above, and the second electronic tag that is heavy in weight is disposed below as a weight.

  Moreover, since the position of the fulcrum is disposed between the electronic tag and the center of gravity, the electronic tag is disposed above the fulcrum, so that a reduction in communication capability due to the influence of height can be reduced.

  Further, by arranging the position of the fulcrum between the first electronic tag and the second electronic tag, the first electronic tag is arranged above the fulcrum and the center of gravity, so A decrease in communication capability of the first electronic tag due to the influence can be reduced.

The first electronic tag is connected to power supply means for accumulating or generating electric charges as a power supply for the first electronic tag,
The second electronic tag can be configured not to be connected to power supply means for accumulating or generating a charge as a power source for the second electronic tag. Connected to power supply means for accumulating or generating charge as a power supply,
The electronic tag device, wherein the second electronic tag is not connected to power supply means for accumulating or generating a charge as a power supply for the second electronic tag. . That is, since the passive tag that is easily affected by the height is disposed above the active tag, it is possible to reduce a decrease in the communication capability of the passive tag due to the height.

  According to the present invention, it is possible to reduce the influence of the inclination of the article to be managed, the influence of the multipath generated in the radio signal, and the influence of the height of the article to be managed in a realistic use state. Stable communication is possible under certain conditions.

(First embodiment)
One embodiment of the electronic tag device of the present invention will be described below with reference to FIGS. 1 to 3 and FIG.

  FIG. 1 is a perspective view showing an external appearance of the electronic tag device according to the first embodiment. FIG. 2 is a front view showing a stationary state of the electronic tag device shown in FIG. FIG. 3 is a schematic diagram showing the relationship between the swinging state of the electronic tag device shown in FIG. 1 and the magnetic field strength distribution. FIG. 10A is a perspective view showing the mounting structure of the electronic tag in the first embodiment, and FIG. 10B is a front view of the electronic tag device shown in FIG. FIG. 10C is a cross-sectional view taken along line II of the electronic tag device shown in FIG.

  Various items can be managed individually by using an electronic tag and a reader / writer. Here, as a specific example of the monitoring target, the use of monitoring the passage of school children attending school Is assumed. Actually, schoolchildren such as elementary school students who go to and from school often have school bags at all times, so it is possible to monitor the passage of schoolchildren by attaching an electronic tag to each school bag. Of course, it is also conceivable to attach an electronic tag to an article other than the school bag.

  In order to actually attach an electronic tag to an article such as a school bag, the electronic tag device 10 shown in FIG. 1 is used in this example. As shown in FIGS. 1 and 10, an electronic tag storage case 10 c constituting the main body of the electronic tag device 10 is formed in a rectangular shape and is formed in a thin plate shape. The electronic tag storage case 10c is made of an electrically insulating material such as plastic.

  Near the center of the electronic tag device 10, that is, near the center of the electronic tag storage case 10c, a fulcrum 11 is provided. This fulcrum 11 is a portion that supports the electronic tag device 10 itself, and as a specific example, it is a through hole that penetrates the electronic tag storage case 10c in the thickness direction. When the electronic tag device 10 is attached to an article such as a school bag, a pin is provided on a base fixed to the article, and the electronic tag device 10 is attached so that the pin penetrates the fulcrum 11 of the electronic tag device 10. do it. However, the diameter of the fulcrum 11 needs to have a margin so that the electronic tag device 10 can swing around the fulcrum 11 with the pin inserted in the fulcrum 11. The base and pins are preferably made of an electrically insulating material such as plastic so as not to affect communication. Of course, the member for swingably attaching the electronic tag device is not limited to a member such as a combination of a base and a pin, and the electronic tag device is attached on an arbitrary member that can swing around its fulcrum. be able to.

  As shown in FIGS. 1 and 10, the electronic tag storage case 10c constituting the main body of the electronic tag device 10 has two storage portions 10a and 10b formed at different positions. The storage unit 10a and the storage unit 10b may be anything that can hold the tag, such as a recess formed on the surface. In this embodiment, a storage portion 10 a is formed above the fulcrum 11, and a storage portion 10 b is formed below the fulcrum 11. That is, the fulcrum 11 is disposed between the storage unit 10a and the storage unit 10b (between a passive tag and an active tag described later).

  A passive tag (first electronic tag) 12 is mounted on the storage portion 10a of the electronic tag storage case 10c, and an active tag (second electronic tag) 13 is mounted on the storage portion 10b. The passive tag 12 and the active tag 13 are constituted by so-called “electronic tags”, and have a function of holding individual identification information assigned in advance and at least transmitting a radio signal including the individual identification information. With this individual identification information, the reader / writer can specify an article, an individual, or the like to which the electronic tag is attached.

  The passive tag 12 is an electronic tag that obtains necessary power by converting the energy of a magnetic field coming from the outside into electric energy, and a battery or the like is not connected as a power source. On the other hand, the active tag 13 is an electronic tag that incorporates, for example, a battery as a power source and is connected to the battery in order to obtain power necessary for its own operation. The active tag 13 is heavier than the passive tag 12 due to structural differences such as the presence or absence of a battery. Therefore, in this embodiment, the active tag 13 is also used as a weight.

  Since the weight of the active tag 13 is large, the center of gravity 14 of the electronic tag device 10 with the passive tag 12 and the active tag 13 attached is positioned below the fulcrum 11 in the vertical direction in the standard state orientation shown in FIG. ing. That is, the state where the center of gravity 14 is located below the fulcrum 11 is the standard state due to the weight balance relationship. However, when acceleration is applied from the outside, the center of gravity 14 is at a position displaced from the fulcrum 11, so that the electronic tag device 10 swings around the fulcrum 11 (around the dotted line in FIG. 1) in the direction of arrow A1 and in the opposite direction A2. Will move.

  In general applications, it is not necessary to attach a plurality of electronic tags to one article. However, for example, when monitoring the passage of school children when going to and from school, the distance from the reader / writer is relatively small. Since both the passive tag 12 that operates only within the range and the active tag 13 that operates within a relatively wide range may be required at the same time, the electronic tag device 10 shown in FIG. is there. In particular, when taking images of schoolchildren at the time of attending school with an IP camera or the like installed on the school road, taking pictures based only on detection of the active tag 13 makes it possible to accurately identify schoolchildren due to the wide communication range. You may not be able to shoot. Therefore, by using the passive tag 12 having a narrower communication range together and using the detection by the passive tag 12 as a trigger for photographing by the IP camera, the possibility of photographing the schoolchild accurately can be increased.

  In the state where acceleration is not applied to the electronic tag device 10 as in the case where the article attached with the electronic tag device 10 does not move, the orientation of the electronic tag device 10 is not changed even if the school bag itself is tilted. It is held stationary in the standard orientation as shown in In this state, the passive tag 12 and the active tag 13 each face a predetermined direction (in this example, the horizontal direction), for example, as shown in FIG.

  Accordingly, it is easy to align the polarization planes of the reader / writer antenna provided for reading information from the electronic tag and the antennas of the passive tag 12 and the active tag 13. For this reason, linearly polarized waves can be used, and the communicable distance of the passive tag 12 can be increased.

  Further, when no acceleration is applied to the electronic tag device 10, the electronic tag device 10 is stationary in a standard state orientation as shown in FIGS. 1 and 2, so that the passive tag is compared with the height h 2 at the position where the active tag 13 is disposed. The height h1 of the position where 12 is disposed is relatively high.

  As described above, generally, the frequency (for example, 900 MHz) of electromagnetic waves used for passive tags is higher than the frequency (for example, 400 MHz) of electromagnetic waves used for active tags, so that the height (distance) increases. The electromagnetic wave of the passive tag is more easily attenuated than the electromagnetic wave of the active tag. Therefore, as shown in FIG. 9, particularly in the case of the passive tag 12, the magnetic field strength is significantly lowered due to the influence of the height, and when the magnetic field strength falls below the threshold value, the operation is stopped. . On the other hand, since the active tag 13 is hardly affected by the height, the performance is not easily deteriorated even if it is disposed below. Therefore, by arranging the passive tag 12 so that the height h1 of the passive tag 12 is larger than the height h2 of the active tag 13 in the standard state as shown in FIG. As shown in FIG. 8, it is assumed that the passive tag antenna 100c and the active tag antenna 100d of the reader / writer are installed at higher positions than the normal height of various articles.

  On the other hand, when a schoolchild goes to school with a school bag on his / her back, acceleration is periodically applied to the electronic tag device 10 with a change in the movement of the human body during walking. When acceleration is applied, the electronic tag device 10 swings around the fulcrum 11. By this swinging, the positions of the passive tag 12 and the active tag 13 attached to the electronic tag device 10 are also moved in the horizontal direction as shown in FIG.

  In general, there are reflectors 102a and 102b such as various buildings around a road or the like as shown in FIG. 6, and therefore in an environment where the electronic tag device 10 is actually used, a reader / writer, an electronic tag, The radio signal transmitted between the two propagates through a plurality of propagation paths P1, P2. Therefore, the multipath effect that the electromagnetic waves propagating through the respective propagation paths interfere with each other appears. Due to this influence, as shown in FIG. 7, null points indicating local attenuation and fluctuation are formed in the magnetic field intensity distribution according to the distance from the transmitting antenna 100 of the reader / writer. That is, when the electronic tag exists at a position where the distance from the reader / writer corresponds to the null point, the magnetic field intensity reaching the electronic tag is remarkably reduced, and the passive tag 12 becomes inoperable.

  Since the range of the null point (Δx0 in FIG. 3) is formed only in a relatively small local range, communication is possible if an electronic tag appears outside this range. The electronic tag device 10 shown in FIG. 1 is configured such that the electronic tag device 10 swings due to the acceleration applied to the fulcrum 11 by the movement of an article to be managed to which the electronic tag is attached. The distance (Δx1) by which the center of the electromagnetic field intensity of the antenna portion (not shown) of the passive tag 12 or the active tag 13 shown in FIG. 3 moves varies depending on the acceleration applied from the outside. Here, the dimensions and positional relationship of each part (particularly the distance between the fulcrum 11 and the passive tag 12 or the active tag 13) are determined so that Δx1 is larger than Δx0.

  The range of the null point (Δx0) is the number of multipath paths at the null point, the intensity of multipath vector synthesis, the wavelength of electromagnetic waves forming the multipath, and the reflections such as the reflectors 102a and 102b in FIG. It varies depending on the electromagnetic wave absorption rate of the object. Accordingly, as shown in FIGS. 3 and 6, the null point range (Δx0) and the depth (the degree of attenuation of the magnetic field strength) change for each occurrence location. In the example of FIGS. 3 and 6, the rightmost null point (farthest null point) has a wide range, but the depth is small, and the leftmost null point (farthest null point) has a range of Narrow but deep. Therefore, the distribution of the multipath and the null point is grasped in advance from the path of the multipath, the wavelength of the electromagnetic wave forming the multipath, the electromagnetic wave absorption rate of the reflector, and the like in the space using the reader / writer and the electronic tag device. Then, at each null point, Δx0 is obtained by, for example, averaging the null point range of the magnetic field strength h0 or less with which the reader / writer can communicate within a predetermined null point.

  On the other hand, Δx1 is attached to the electronic tag device in addition to the physical properties of the electronic tag device, such as the size, shape, weight, and dimensions of each part of the electronic tag storage case (the position of the fulcrum). It is obtained by taking into account the movement of the object to be detected, especially acceleration. Therefore, in consideration of the properties of the object to be mounted, the dimensions and positional relationships of the parts of the electronic tag device and the electronic tag are determined so that Δx1 larger than the maximum value of Δx0 is generated. .

  The specific attachment structure of the electronic tag with respect to the electronic tag apparatus 10 is shown in FIGS. 10 (a) to 10 (c). In this example, as shown in FIG. 10A, the storage portions 10a and 10b are formed as recesses provided on one surface of the electronic tag storage case 10c. Further, as shown in FIG. 10C, a predetermined interval d1 is provided between the storage portion 10a and the storage portion 10b. The reason for providing such an interval d1 is as follows.

  When the passive tag 12 is used, for example, as shown in FIG. 12, the magnetic field component of the radio signal emitted from the antenna 101 of the reader / writer 103 passes through the antenna coil 12 a inside the passive tag 12, thereby generating power. Since this is induced, this power is used as the power supply power of the passive tag 12 itself, specifically, the driving power of the IC chip built in the passive tag 12.

  Further, depending on the application of the system, both the passive tag 12 and the active tag 13 may be required to monitor the same article. However, the frequency band used by the passive tag 12 for wireless communication and the active tag 13 By allocating frequencies so that they do not overlap with the frequency bands used for wireless communication, basically both can coexist.

  However, since the metal component which is a conductor is actually contained in the active tag 13, the influence of this metal component appears. Specifically, for example, as shown in FIG. 13, when the passive tag 12 and the active tag 13 are arranged close to each other, an eddy current is generated inside the metal included in the active tag 13, and this eddy current is generated. The magnetic field radiated from the antenna 101 of the reader / writer 103 is canceled by the influence of the magnetic flux generated by the current. Therefore, even when different frequency bands are used, if the passive tag 12 and the active tag 13 are close to each other, sufficient power is not induced in the passive tag 12 and the passive tag 12 cannot be operated. become.

  Therefore, for example, as shown in FIGS. 10 (a) to 10 (c), when the passive tag 12 and the active tag 13 are separated from each other and a space in which no metal exists (corresponding to d1) is provided, Even if the magnetic flux is generated by the eddy current inside the active tag 13, the magnitude of the magnetic field reaching the passive tag 12 does not change greatly. Therefore, the passive tag 12 and the active tag 13 can be used simultaneously.

(Second Embodiment)
Another embodiment relating to the electronic tag device of the present invention will be described below. This form is a modification of the first embodiment. Since this embodiment has a few different points from the first embodiment, the illustration is omitted, and the same drawing as that of the first embodiment is used for description.

  In this embodiment, a weight having a special equivalent weight is attached to the storage portion 10b of the electronic tag storage case 10c instead of the active tag 13 shown in FIG. The passive tag 12 is disposed above the fulcrum 11 as in FIG.

  That is, since it is sufficient to provide only one of the passive tag 12 and the active tag 13 for general use, the active tag 13 is omitted and the weight is replaced with a position different from the passive tag 12 (the original active tag 13 position). Therefore, the function is almost the same as that of the first embodiment. That is, since the center of gravity 14 is located at a position shifted from the fulcrum 11, the orientation of the electronic tag device 10 is constant in a steady state where no acceleration is applied, and the passive tag 12 swings when acceleration is applied.

(Third embodiment)
Another embodiment of the electronic tag device of the present invention will be described below with reference to FIGS. 11 (a) to 11 (c). FIG. 11A is a perspective view showing an appearance of the electronic tag device according to the third embodiment, and FIG. 11B is a front view of the electronic tag device shown in FIG. FIG. 11C is a cross-sectional view taken along line II-II of the electronic tag device shown in FIG.

  This form is a modification of the first embodiment. In this embodiment, as shown in FIGS. 11A to 11C, the attachment structure of the passive tag 12 and the active tag 13 is different from that of the first embodiment. The rest is the same as in the first embodiment.

  As shown in FIGS. 11A to 11C, in this embodiment, the passive tag 12 is attached to one surface in the thickness direction of the electronic tag storage case 10c, and the surface opposite to the electronic tag storage case 10c is mounted. The active tag 13 is attached, and the passive tag 12 and the active tag 13 are arranged in a state of facing each other in the thickness direction.

  Therefore, when the passive tag 12 and the active tag 13 are close to each other, there is a possibility that the influence of magnetic flux generated by the eddy current inside the active tag 13 appears as shown in FIG. Therefore, in this embodiment, as shown in FIG. 11C, the electronic tag device 10 is formed so that there is a sufficient distance d2 in the thickness direction between the position of the surface to which the passive tag 12 is attached and the surface to which the active tag 13 is attached. It is.

  For this reason, even if a magnetic flux is generated by an eddy current inside the active tag 13, the magnitude of the magnetic field reaching the passive tag 12 hardly changes. Therefore, the passive tag 12 and the active tag 13 can be used simultaneously.

  Further, when the active tag 13 is attached to the electronic tag storage case 10c, the battery is connected in such a direction that the battery connected to the active tag 13 is disposed on the lower side. Thereby, as in the case of the first embodiment, since the center of gravity of the electronic tag device 10 is arranged at a position sufficiently lower than the fulcrum, the electronic tag device 10 is likely to swing due to acceleration applied from the outside. .

  In addition, as shown in the lower part of FIG. 3, an embodiment in which one of the active or passive electronic tags is housed in the housing portion of the electronic tag housing case is also included in the electronic tag device of the present invention. This is because, due to the weight of the electronic tag, the electronic tag device can swing around the fulcrum, and the electronic tag itself can swing relative to the external mounting member, and the effects of the present invention can be achieved.

  Although various embodiments of the present invention have been described above, the present invention is not limited to the matters shown in the above-described embodiments, and those skilled in the art can make modifications and applications based on the description and well-known techniques. This is also the scope of the present invention, and is included in the scope for which protection is sought.

  By using the electronic tag device of the present invention, for example, the influence of the inclination of the article to be managed such as a school bag, the influence of multipath generated in the radio signal, the influence of the height of the article to be managed, Since stable communication can be realized, it is useful for improving reliability by applying it to various management systems for crime prevention purposes.

The perspective view which shows the external appearance of the electronic tag apparatus of 1st Embodiment The front view which shows the stationary state of the electronic tag apparatus shown in FIG. The schematic diagram which shows the relationship between the rocking | fluctuation state of an electronic tag apparatus shown in FIG. 1, and magnetic field intensity distribution Schematic diagram showing the propagation state of electromagnetic waves in the case of circular polarization Schematic diagram showing the propagation state of electromagnetic waves in the case of linear polarization Schematic diagram showing the propagation state of electromagnetic waves when multipath occurs Graph showing the relationship between magnetic field strength and distance when multipath occurs Schematic diagram showing an example of the positional relationship in the height direction between the antenna of the reader / writer and the antenna of the electronic tag Graph showing an example of the relationship between antenna height and magnetic field strength of an electronic tag FIG. 10A is a perspective view showing the attachment structure of the electronic tag in the first embodiment, and FIG. 10B is a front view of the electronic tag device shown in FIG. 10 (c) is a sectional view taken along line II of the electronic tag device shown in FIG. 10 (b). FIG. 11A is a perspective view showing the appearance of the electronic tag in the third embodiment, and FIG. 11B is a front view of the electronic tag device shown in FIG. (C) is sectional drawing along the II-II line of the electronic tag apparatus shown in FIG.11 (b). Schematic diagram showing an example of the state of the magnetic field component of the electromagnetic wave transmitted from the reader / writer antenna and reaching the electronic tag Schematic diagram showing an example of the state of the magnetic field component of the electromagnetic wave transmitted from the reader / writer antenna and reaching the electronic tag

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Electronic tag apparatus 10a, 10b Storage part 10c Electronic tag storage case 11 Support point 12 Passive tag 13 Active tag 14 Center of gravity

Claims (6)

An electronic tag device comprising at least one electronic tag that stores pre-assigned individual identification information and transmits a radio signal including the individual identification information,
At a position shifted from the center of gravity of the electronic tag device, there is a fulcrum supported by an external member,
When the center of gravity is below the fulcrum, the electronic tag is disposed above the center of gravity,
An electronic tag device capable of swinging around the fulcrum as a rotation center. The electronic tag device according to claim 1,
The electronic tag is in a range exceeding the distance range on the transmission path, which is caused by mutual interference between the wireless signal passing through a plurality of transmission paths and an external device having an electronic tag reading function. An electronic tag device having a distance between the fulcrum and the electronic tag that can swing. The electronic tag device according to claim 1,
At least two electronic tags,
When the first electronic tag and the second electronic tag having a larger weight than the first electronic tag have the center of gravity below the fulcrum, the first electronic tag is the second electronic tag. An electronic tag device arranged above the device. The electronic tag device according to claim 1,
An electronic tag device in which the fulcrum is disposed between the electronic tag and the center of gravity. The electronic tag device according to claim 3,
An electronic tag device in which the fulcrum is disposed between the first electronic tag and the second electronic tag. The electronic tag device according to claim 3,
The first electronic tag is connected to power supply means for accumulating or generating electric charge as a power supply for the first electronic tag,
The electronic tag device, wherein the second electronic tag is not connected to power supply means for accumulating or generating a charge as a power supply for the second electronic tag.

Images