JP2011133943A - Wireless tag communication device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wireless tag communication device effectively performing wireless communication with a wireless tag according to a movement distance of the wireless tag communication device even when an operator grasps the wireless tag communication device and moves in a wide range. <P>SOLUTION: The wireless tag communication device including an antenna capable of transmitting/receiving a signal for performing the communication with the wireless tag includes a reference point setting means setting a reference point of a movement start of the wireless tag communication device; a position detection means detecting present position coordinates of the wireless tag communication device; a movement distance detection means detecting the movement distance by which the wireless tag communication device moves by a difference in the position coordinates between the position coordinates detected by the position detection means and the reference point; a movement distance decision means deciding whether the movement distance detected by the movement distance detection means exceeds a prescribed movement distance; and a directivity control means performing control to change communication directivity about the antenna according to a result detected by the movement distance decision means. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a wireless tag communication apparatus that performs wireless communication with an RFID tag via an antenna.

  Conventionally, information is read and written in a contactless manner between a wireless tag having a wireless tag circuit portion having an IC circuit portion and a tag antenna connected to the IC circuit portion for transmitting and receiving information, and the wireless tag communication device. A Radio Frequency Identification (hereinafter referred to as RFID) system is known.

  This RFID system has been put into practical use in various fields, and in industries such as sales / distribution, it may be used for article management such as inventory work of goods that is regularly performed in order to check the stock of products.

  For example, in Patent Document 1, when an operator performs reading work of a wireless tag using a portable wireless tag information reading device, the wireless tag is used to prevent repeated communication with the same wireless tag. A folding operation when the information reader is shaken and reciprocated is detected, and communication is performed by controlling directivity, polarization plane direction, and the like based on the detection result. Thereby, information can be efficiently transmitted and received with a plurality of wireless tags.

JP 2009-53917 A

  By the way, when performing the above inventory work, a plurality of shelves such as a factory and a warehouse are provided, and an operator may perform the inventory work over a wide range. In such a case, when the movement range of the operator is widened, it is not known where the reading operation is performed as a base point, and reading omission may occur.

  The present invention is effective in accordance with the moving distance from the movement start reference point even when the operator holds the RFID tag communication device and moves in a wide range, for example, for inventory work. An object of the present invention is to provide a wireless tag communication apparatus capable of performing wireless communication with a wireless tag.

  In order to achieve the above object, a wireless tag communication device according to a first aspect of the present invention is a wireless tag communication device including an antenna capable of transmitting and receiving a signal for communicating with a wireless tag, and the movement of the wireless tag communication device is started. A reference point setting means for setting a reference point of the wireless tag, a position detection means for detecting a current position of the RFID tag communication device, and a difference between the position detected by the position detection means and the reference point. A moving distance detecting means for detecting a moving distance moved by the communication device; a moving distance determining means for determining whether the moving distance detected by the moving distance detecting means exceeds a predetermined moving distance; and the moving distance The antenna further comprises directivity control means for performing control to change communication directivity for the antenna according to a determination result by the determination means.

  In addition to the configuration of the first invention, the RFID tag communication apparatus of the second invention is characterized in that the directivity control is performed when the moving distance determining means determines that the moving distance exceeds a predetermined moving distance. The means is characterized in that the antenna is controlled to change to a wider communication directivity than the current communication directivity.

  According to a third aspect of the present invention, in addition to the first aspect, the wireless tag communication apparatus includes a movement speed detection means for detecting a movement speed in a predetermined section to the current position of the RFID tag communication apparatus, and the movement speed detection means. A moving speed determining means for determining whether or not the detected moving speed is equal to or less than a predetermined moving speed, and the moving distance determining means determines that the moving distance is equal to or less than a predetermined moving distance; In addition, the directivity control means performs control to change communication directivity for the antenna in accordance with a determination result of the moving speed determination means.

  In addition to the third invention, the RFID tag communication apparatus according to a fourth aspect of the present invention is configured so that, when the moving speed determining unit determines that the moving speed is equal to or lower than a predetermined moving speed, the directivity control unit includes: The antenna is controlled to change to a communication directivity narrower than the current communication directivity.

  In addition to the third invention, the wireless tag communication device of the fifth invention is an operation information acquisition means for acquiring operation information indicating that the wireless tag communication device is transmitting and receiving a signal for communicating with the wireless tag. And an operation information determining unit that determines whether or not the operation information has been acquired by the operation information acquiring unit, and the moving speed determining unit determines that the moving speed exceeds a predetermined moving speed. And when the operation information determination unit determines that the operation information has been acquired, the directivity control unit performs communication with the antenna that is narrower than the current communication directivity. It is characterized by performing control to change to directivity.

  In addition to the second invention described above, the RFID tag communication apparatus of the sixth invention, when the directivity control means performs control to change the antenna to a communication directivity wider than the current communication directivity, The reference point setting means resets the reference point.

  According to the wireless tag communication device of the invention of claim 1, for example, when the operator moves while holding the wireless tag communication device, the movement distance of the current wireless tag communication device from the reference point for starting movement Control is performed to change the communication directivity of the antenna depending on whether or not exceeds a predetermined moving distance. Therefore, when the wireless tag communication apparatus moves, signals can be efficiently transmitted and received with the wireless tag according to the movement distance from the movement start reference point.

  According to the wireless tag communication device of the invention according to claim 2, in addition to the effect of claim 1, the moving distance of the wireless tag communication device at the current position from the reference point for starting movement exceeds a predetermined moving distance. In this case, control is performed to widen the communication directivity of the antenna. Therefore, reading omissions can be reduced and signals can be efficiently transmitted and received with the wireless tag.

  According to the wireless tag communication device of the invention of claim 3, in addition to the effect of claim 1, when the movement distance of the wireless tag communication device at the current position from the movement start reference point is equal to or less than a predetermined movement distance In addition, control is performed to change the communication directivity of the antenna according to whether or not the moving speed of the RFID tag communication apparatus in a predetermined section up to the current position coordinates is equal to or lower than the predetermined moving speed. Thereby, according to the movement state of a wireless tag communication apparatus, the signal transmission / reception with a wireless tag can be performed effectively.

  According to the wireless tag communication device of the invention of claim 4, in addition to the effect of claim 3, when the movement distance of the wireless tag communication device at the current position from the movement start reference point is equal to or less than a predetermined movement distance In addition, when the moving speed of the wireless tag communication apparatus is equal to or lower than the predetermined moving speed in a predetermined section up to the current position coordinates, control for narrowing the communication directivity of the antenna is performed. In the case of such movement of the RFID tag communication apparatus, it is assumed that the RFID tag communication apparatus hardly moves or moves in a relatively narrow range. Therefore, the sensitivity in the front direction of the antenna can be increased, and signals can be efficiently transmitted and received with the wireless tag to be read.

  According to the wireless tag communication device of the invention according to claim 5, in addition to the effect of the invention according to claim 3, the movement distance of the wireless tag communication device at the current position from the movement start reference point is equal to or less than a predetermined movement distance. An operation that indicates that when the moving speed of the RFID tag communication device exceeds the predetermined moving speed in a predetermined section up to the current position coordinates, signal transmission / reception with the wireless tag is being performed. When information is acquired, the communication directivity of the antenna is narrowed. In the case of such movement of the RFID tag communication apparatus, it is assumed that the RFID tag communication apparatus is moving while performing a reading operation. Therefore, the sensitivity in the front direction of the antenna can be increased, and signals can be efficiently transmitted and received with the wireless tag to be read.

  According to the wireless tag communication device of the invention of claim 6, in addition to the effect of the invention of claim 2, when control for widening the communication directivity of the antenna is performed, the reference point for starting movement is reset. Is done. Therefore, the communication directivity of the antenna can be controlled according to the moving distance from the point, so that signals can be effectively transmitted and received with the wireless tag.

It is a conceptual diagram showing the example which performs article management using the wireless tag communication apparatus of this embodiment. It is a functional block diagram showing the structure of a wireless tag communication apparatus. It is a table | surface which shows an example of the phase delay amount of the electric power feeding to the front element with respect to the back element memorize | stored in flash ROM. It is a table | surface which shows the relationship between the phase delay amount of the electric power feeding to the front element with respect to the back element of the antenna of this embodiment, a front gain, and a half value width of electric power. It is a table | surface which shows an example of the memory content memorize | stored in flash ROM. It is a table | surface which shows an example of the relationship between the position coordinate of a radio | wireless tag communication apparatus for every predetermined time, the movement distance from a reference point, the movement speed of a predetermined area, and the communication directivity of an antenna. It is a flowchart showing the control procedure performed by CPU of a wireless tag communication apparatus.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In FIG. 1, an example in which the operator M performs article management using the RFID tag communication apparatus 100 of the present embodiment will be described. Books B are stored in a plurality of storage shelves S, and a radio tag 200 for identifying the book B is attached to the spine of each book B.

  If the storage shelf S is invented, the operator M performs transmission and reception of information with respect to the wireless tags 100 of the books B in all the storage shelves S while holding and moving the wireless tag communication device 100. Is called. Note that the storage shelf S is omitted as appropriate, and there are many other storage shelves S. Hereinafter, each configuration will be described in order.

  The configuration of the wireless tag communication device 100 will be described with reference to FIGS. 1 and 2. The wireless tag communication device 100 transmits and receives signals to and from the wireless tag 200 via an antenna 150. The wireless tag communication device 100 includes a main body 110 and an antenna 150. The wireless tag communication device 100 includes a RAM 112, a flash ROM 113, a display unit 114, a CPU 115, an RFID chip set 116, a transmission / reception separating unit 117, an acceleration sensor 118, and an input unit 119. These are electrically connected by a bus.

  The antenna 150 is connected to the main body 110 and functions as a transmission / reception antenna for the wireless communication. In the present embodiment, the antenna 150 is a so-called array dipole antenna.

  The accelerometer 118 may be a known sensor and will not be described in detail. In this embodiment, the acceleration sensor 118 is a biaxial type, and the main body 110 of the wireless tag communication device 100 has a width direction (x-axis direction in FIG. 1) and a longitudinal direction. The movement acceleration in the direction corresponding to each direction (y-axis direction in FIG. 1) is individually detected. Further, the movement acceleration in the z-axis direction in FIG. 1 may be detected, or a speed sensor may be used in place of the acceleration sensor 118. In the case of movement of the RFID tag communication apparatus 100, in the present embodiment, acceleration detection values with signs corresponding to the x-axis and y-axis directions from the acceleration sensor 118 are obtained by a known method every predetermined time from the start of movement. Accumulated. Thereby, the position coordinates of the RFID tag communication apparatus 100 and the moving speed are calculated.

  The CPU 115 is a central processing unit, and executes various controls including communication control with the wireless tag 200 by the wireless tag communication device 100. The RFID tag communication apparatus 100 also includes a flash ROM 113 as storage means and a RAM 112 that is a write / read memory as needed. In parallel with the use of the temporary storage function of the RAM 112, the CPU 115 controls the entire RFID tag communication apparatus 100 by performing signal processing in accordance with a program stored in advance in the flash ROM 113.

  Further, the CPU 115 transmits a predetermined transmission signal to the wireless tag 200 via the RFID chip set 116 and demodulates a reply signal returned from the wireless tag 200 according to the transmission signal. The tag communication device 100 performs communication control with the wireless tag 200.

  Further, the CPU 115 controls the phase shifter 152 described later, that is, controls the phase delay amount when the transmission signal supplied from the distributor 151 is supplied to the front element 156 via the phase shifter 152. The communication directivity of the antenna 150 is controlled by controlling the phase delay amount of the front element 156 with respect to the rear element 155. A detailed control method will be described later.

  The RFID chip set 116 executes signal processing such as outputting the transmission signal in response to a command from the CPU 115 and demodulating a reply signal from the wireless tag 200.

  The transmission / reception separating unit 117 supplies the transmission signal output from the RFID chip set 116 to the distributor 151 and also supplies the reception signal input via the distributor 151 to the RFID chip set 116. As the transmission / reception separating unit 117, a directional coupler, a circulator, or the like is preferably used.

  The input unit 119 is a numeric keypad, a trigger switch, or the like for inputting instructions and information from the operator. The operator M starts the reading operation of the wireless tag communication device 100 by operating the input unit 119. Therefore, as described later, the CPU 115 determines whether or not the wireless tag communication device 100 is transmitting / receiving a signal to / from the wireless tag 200 based on whether or not predetermined operation information is acquired from the input unit 119. The display unit 114 includes, for example, a liquid crystal display and displays various information and messages.

  The distributor 151 supplies the transmission signal supplied from the RFID chip set 116 to the front element 156 via the rear element 155 and the phase shifter 152. At this time, a transmission signal that is a high-frequency signal is transmitted from the rear element 155 toward the front element 156. In the present embodiment, the length La of the front element 156 is about a half wavelength, and the front element 156 and the rear element 155 are connected to each other with a distance of about 1/16 wavelength. The length Lb of the rear element 155 is longer than the length of the front element 156 by several% in the left-right direction in FIG.

  Next, control of communication directivity of the antenna 150 according to the present embodiment will be described with reference to FIG. In the table of FIG. 3, when the communication directivity of the antenna 150 is controlled, the degree of communication directivity and the phase delay amount of power feeding of the front element 156 and the rear element 155 are stored in association with each other. In the present embodiment, the communication directivity of the antenna can be controlled in three stages: “wide”, “medium”, and “narrow”.

  Note that the communication directivity of the antenna 150 increases as the phase delay amount between the front element 156 and the rear element 155 decreases, and the communication directivity decreases as the phase delay amount increases.

  In FIG. 3, the communication directivity is wider when the phase delay amount is 90 deg than when the phase delay amount of the power feeding of the front element 156 and the rear element 155 is 5 deg. Further, the communication directivity is wider when the phase delay amount is 180 deg than when the phase delay amount is 90 deg.

  In FIG. 4, the relationship among the phase delay amount (deg) of power feeding to the front element 156 with respect to the rear element 155 of the antenna 150, the front gain (dBi), and the power half width (deg) will be described. In addition, this numerical value is an example and does not show an absolute value.

  As the phase delay amount of the power feeding to the front element 156 with respect to the rear element 155 increases, the front gain of the antenna 150 increases and the power half-value width decreases. This indicates that the larger the feed phase delay amount to the front element 156 relative to the rear element 155, the narrower and sharper the communication directivity of the antenna 150 becomes, and the stronger the radio wave is emitted in a specific direction.

  On the other hand, the smaller the phase delay amount of power feeding to the front element 156 with respect to the rear element 155, the smaller the front gain of the antenna 150 and the wider the half value width of the power. This is because, as the amount of phase delay in feeding to the front element 156 relative to the rear element 155 becomes smaller, the width of communication directivity of the antenna 150 becomes wider and the radiation direction of radio waves becomes wider, but the degree of radio wave radiation is relatively weak. It shows that it becomes.

  Next, an example of stored contents stored in the flash ROM 113 of the wireless tag communication device 100 will be described with reference to FIG. The flash ROM 113 stores a predetermined moving distance and a predetermined moving speed. In this embodiment, as shown in FIG. 5, “5 m” is stored as a predetermined moving distance and “0.5 m / s” is stored as a predetermined moving speed.

  This predetermined movement distance is determined in consideration of the communicable range of the RFID tag communication apparatus 100, for example. As a result, when moving beyond a predetermined movement distance from the movement start reference point, there is a wireless tag that is newly included in the communication range regardless of whether or not communication is initially performed. Therefore, in order to communicate with the wireless tag as efficiently as possible and eliminate reading omission, reading is performed with a wide communication directivity range.

  In addition, for example, a speed that is assumed when the operator moves while holding the RFID tag communication apparatus 100 is set as the predetermined movement speed. When the movement speed in a predetermined section to the current position coordinates is equal to or lower than the predetermined movement speed, the operator who holds the RFID tag communication device is stationary or stays within a relatively short movement distance. It ’s like that. In such a case, in order to effectively communicate with the wireless tag 200, the communication directivity of the antenna is narrowed to increase the sensitivity in the front direction of the antenna.

  Here, as the predetermined section, in this embodiment, as described later, the time interval of 0.5 seconds immediately before the current position is set as the predetermined section, but in addition, the movement from the reference point to the current position is performed. The distance may be a predetermined section.

  As described above, when the RFID tag communication apparatus 100 is not moving or is in a relatively narrow range even if it is moving, the communication directivity of the antenna is controlled to be “narrow” in the present embodiment. Regarding the determination of whether the RFID tag communication apparatus 100 is not moving or is within a relatively narrow range even if it is moving, the movement speed in a predetermined section up to the current position of the RFID tag communication apparatus 100 is a predetermined speed. Judgment is made based on whether or not:

  In addition, when the movement speed in the predetermined section to the current position exceeds the predetermined movement speed and operation information for performing wireless communication with the wireless tag 200 is acquired, the wireless tag communication apparatus 100 is changed. It is assumed that the grasped operator is performing a wireless tag reading operation while moving. In this case, the communication range moves with the movement of the RFID tag communication apparatus 100 (in the x-axis direction in FIG. 1), and it is not necessary to increase the communication directivity more than necessary, and it is preferable to increase the sensitivity of the antenna. Therefore, the communication directivity of the antenna of the RFID tag communication apparatus 100 is narrowed. In this embodiment, the communication directivity of the antenna is controlled to “medium”.

  Whether or not the wireless tag communication device 100 is performing a reading operation is determined based on whether or not operation information for transmitting and receiving signals to and from the wireless tag 200 has been acquired, as will be described later.

  Next, the relationship between the position coordinates of the RFID tag communication device every predetermined time, the movement distance from the reference point, the movement speed of the predetermined section, and the communication directivity of the antenna will be described with reference to FIG.

  First, acceleration is detected every predetermined time from a reference point for starting the movement of the RFID tag communication apparatus 100, and the position coordinates, movement distance, and coordinates of the RFID tag communication apparatus 100 for each predetermined time calculated by a known method. The moving speed in between is stored in the flash ROM 113.

  In the present embodiment, the acceleration of the RFID tag communication apparatus 100 is detected every 0.5 seconds, and the movement distance (m) from the reference point of the movement start of the RFID tag communication apparatus 100 and 0. The moving speed (m / s) for 5 seconds is calculated. In the present embodiment, the reference point is automatically set when the RFID tag communication apparatus 100 is turned on and an application is started.

  Here, regarding the resetting of the reference point for starting movement, as will be described later, the communication directionality of the antenna 150 is controlled to be wider than the current communication directionality. When the operation information for performing transmission / reception of the wireless tag communication apparatus 100 is acquired, the reference point for starting the movement of the RFID tag communication apparatus 100 may be reset. By doing in this way, the communication directivity of the antenna 150 can be controlled according to the moving distance of the RFID tag communication apparatus 100 from the reset reference point.

  Specifically, an example of antenna directivity control when the RFID tag communication apparatus 100 moves from the movement start reference point will be described with reference to FIG. Here, as shown in FIG. 1, a case where the operator M holds the wireless tag communication device 100 and moves linearly in the positive direction of the x axis will be described. It is assumed that the communication directivity of the antenna 150 is set to “wide” as an initial setting.

  The wireless tag communication device 100 starts moving from the coordinates (0, 0) as the reference point for starting the movement, and the current position coordinates of the wireless tag communication device 100 0.5 seconds later are (0.6, 0), the moving distance after 0.5 seconds from the reference point is 0.6 m, and the moving speed for 0.5 seconds immediately before the current position is 1.2 m / s.

  Similarly, the movement distance from the reference point of the RFID tag communication apparatus 100 and the movement speed for 0.5 seconds immediately before the current position are calculated at intervals of 0.5 seconds. Assume that operation information for transmitting and receiving signals via the antenna 150 of the RFID tag communication apparatus 100 is acquired 1.5 seconds after the start of movement. At this time, the moving speed is 1.0 m / s, which exceeds the predetermined moving speed 0.5 m / s, and operation information for transmitting and receiving signals via the antenna is acquired. The communication directivity of the antenna 150 of the communication apparatus 100 is controlled to “medium”.

  Thereafter, until 4 seconds after the RFID tag communication apparatus 100 starts moving, the moving speed for 0.5 seconds immediately before the current position exceeds 0.5 m / s, and a signal is transmitted via the antenna 150. Assuming that operation information for transmission / reception is acquired, the communication directivity of the antenna is maintained at “medium”.

  Next, after 4.5 seconds from the reference point, the moving speed for 0.5 seconds immediately before reaching the current position becomes 0.4 m / s, which is a predetermined moving speed of 0.5 m / s or less. The communication directivity of the antenna 150 is controlled to be “narrow”. Since the moving speed is 0.5 m / s or less, which is a predetermined moving speed, continuously until 5.5 seconds later, the communication directivity of the antenna 150 is kept “narrow”.

  After 6.0 seconds from the start of movement, the movement distance becomes 5.3 m, and the movement distance from the movement start reference point exceeds the predetermined movement distance of 5 m. To be controlled.

  Next, a process executed by the CPU 115 of the RFID tag communication apparatus 100 will be described with reference to FIG. This flow starts when the RFID tag communication apparatus 100 is turned on, and is repeated at predetermined time intervals until the power is turned off. In this embodiment, it is repeated at intervals of 0.5 seconds.

  In step S110, a reference point for starting movement of the RFID tag communication apparatus 100 is set. In this embodiment, the reference point is automatically set when the power is turned on.

  In step S120, the current position coordinates are detected from the acceleration sensor 118, and the moving distance from the reference point of the RFID tag communication apparatus 100 is calculated. Further, the moving speed of the RFID tag communication apparatus 100 in a predetermined section up to the current position is calculated. In the present embodiment, the predetermined section to the current position is 0.5 seconds immediately before the position coordinates of the current position are detected.

  In step S130, it is determined whether or not the movement distance of the RFID tag communication apparatus 100 exceeds the predetermined movement distance with reference to the value of the predetermined movement distance stored in the flash ROM 113. In the present embodiment, the predetermined moving distance is 5 m as described above. If the moving distance of the wireless tag communication device 100 exceeds the predetermined moving distance, the process proceeds to step S140. On the other hand, when the moving distance of the RFID tag communication apparatus 100 is not more than the predetermined moving distance, the process proceeds to step S150.

  In step S140, the communication directivity of the antenna 150 is widened. Specifically, control is performed so that the phase delay amount of power feeding to the front element 156 with respect to the rear element 155 is 5 deg.

  In step S145, it is determined whether operation information for transmitting / receiving a signal to / from the wireless tag 200 via the antenna 150 has been acquired. If operation information for transmitting / receiving a signal to / from the wireless tag is acquired, the process proceeds to step S146. On the other hand, if operation information for transmitting / receiving a signal to / from the wireless tag has not been acquired, the process proceeds to step S120.

  In step S146, the reference point for starting movement of the RFID tag communication apparatus 100 is reset.

  In step S150, with reference to a predetermined moving speed stored in the flash ROM 113, it is determined whether or not the moving speed of the RFID tag communication apparatus 100 is equal to or lower than the predetermined moving speed. In the present embodiment, the predetermined moving speed is 0.5 m / s as described above. If the moving speed of the wireless tag communication device 100 exceeds the predetermined moving speed, the process proceeds to step S160. On the other hand, when the moving speed of the RFID tag communication apparatus 100 is equal to or lower than the predetermined moving speed, the process proceeds to step S180.

  In step S160, it is determined whether operation information for transmitting / receiving a signal to / from the wireless tag 200 via the antenna 150 has been acquired. If operation information for transmitting / receiving a signal to / from the wireless tag is acquired, the process proceeds to step S170. On the other hand, if operation information for transmitting / receiving a signal to / from the wireless tag has not been acquired, the process proceeds to step S120.

  In step S170, the communication directivity of the antenna 150 is set to “medium”. Specifically, control is performed so that the phase delay amount of power feeding to the front element 156 with respect to the rear element 155 is 90 deg.

  In step S180, the communication directivity of the antenna 150 is set to “narrow”. Specifically, control is performed so that the phase delay amount of power feeding to the front element 156 with respect to the rear element 155 is 180 deg.

  In the above-described embodiment, the processing of step S110 and step S146 for setting the movement start reference point of the RFID tag communication apparatus 100 corresponds to the reference point setting means described in the claims. The position according to claim 6, wherein the current position coordinates are detected from the acceleration sensor 118, and the movement distance from the reference point of the RFID tag communication apparatus 100 and the movement speed of a predetermined section to the current position coordinates are calculated. It corresponds to detection means and movement distance detection means.

  The process of step S130 for determining whether or not the movement distance of the wireless tag communication device 100 exceeds a predetermined movement distance corresponds to the movement distance determination means. The processing of step S140, step S170, and step S180 for performing control to change the communication directivity of the antenna 150 corresponds to directivity control means.

  Moreover, the process of step S150 which judges whether the said moving speed of the RFID tag communication apparatus 100 is below a predetermined moving speed is equivalent to the moving speed judgment means as described in a claim. The process of step S160 for determining whether or not operation information for transmitting / receiving a signal to / from the wireless tag 200 via the antenna 150 corresponds to the operation information acquisition unit and the operation information determination unit described in the claims.

  In the above-described embodiment, the case where the communication directivity of the antenna is changed in three stages has been shown. However, the width of the communication directivity of the antenna may be further finely controlled. Note that the relationship between the antenna communication directivity described in this embodiment is “wide”, “medium”, and “narrow” indicates a relative relationship. For example, the communication directivity of the antenna can be controlled. There may be a maximum value and a minimum value, and an intermediate value may be taken.

  Further, in the present embodiment, when the RFID tag communication apparatus 100 is not moving or is in a relatively narrow range even if it is moving, the communication directivity of the antenna is controlled to be “narrow”, and the RFID tag communication apparatus When 100 is moving and transmitting / receiving signals to / from the wireless tag 200, the communication directivity of the antenna is controlled to “medium”, but the present invention is not limited to this.

  In the two cases as described above, the communication directivity of the antenna 150 is not “medium” or “narrow”, but it is controlled to the same degree or the relative relationship of the width of the communication directivity is reversed. Good.

  Further, regarding the movement of the RFID tag communication apparatus 100 of the present embodiment, the movement in one direction in the x-axis direction in FIG. 1 has been described, but the movement in the reverse direction, the movement in the y-axis direction, and the z-axis direction (not shown). It may be. For example, the moving direction stores a code, a symbol, or the like that can distinguish which direction the moving direction is relative to the width direction of the main body 110 of the RFID tag communication apparatus 100. What is necessary is just to calculate each moving distance and moving speed with respect to the moving direction, and to compare the relationship between the predetermined moving distance and the predetermined moving speed.

  In addition, in the present embodiment, the moving speed of the current position coordinate is calculated from the position coordinate 0.5 seconds before as the moving speed in the predetermined section to the current position coordinate. Other time intervals such as 3 seconds may be used.

  In addition, although not illustrated, the present invention is implemented with various modifications within a range not departing from the gist thereof.

DESCRIPTION OF SYMBOLS 100 RFID tag communication apparatus 118 Acceleration sensor 150 Antenna 155 Rear element 156 Front element 200 Wireless tag

Claims (6)

A wireless tag communication device including an antenna capable of transmitting and receiving a signal for communicating with a wireless tag,
Reference point setting means for setting a reference point for starting movement of the wireless tag communication device;
Position detecting means for detecting a current position of the wireless tag communication device;
A moving distance detecting means for detecting a moving distance moved by the RFID tag communication device based on a difference between the position detected by the position detecting means and the reference point;
A movement distance determination means for determining whether or not the movement distance detected by the movement distance detection means exceeds a predetermined movement distance;
A wireless tag communication apparatus comprising: directivity control means for performing control to change communication directivity for the antenna according to a determination result by the moving distance determination means.   When the moving distance determining means determines that the moving distance exceeds a predetermined moving distance, the directivity control means changes the communication directionality of the antenna to be wider than the current communication directivity. The wireless tag communication device according to claim 1, wherein control is performed. A moving speed detecting means for detecting a moving speed in a predetermined section to the current position of the RFID tag communication device;
A moving speed determining means for determining whether the moving speed detected by the moving speed detecting means is equal to or lower than a predetermined moving speed;
When the moving distance determining unit determines that the moving distance is equal to or less than a predetermined moving distance, the directivity control unit performs communication directivity on the antenna according to the determination result of the moving speed determining unit. The wireless tag communication device according to claim 1, wherein control for changing the characteristics is performed.   When the moving speed determining means determines that the moving speed is equal to or lower than a predetermined moving speed, the directivity control means controls the antenna to change to a communication directivity narrower than the current communication directivity. The wireless tag communication device according to claim 3, wherein: Operation information acquisition means for acquiring operation information indicating that the wireless tag communication device is transmitting and receiving a signal for communicating with the wireless tag;
Operation information determination means for determining whether or not the operation information has been acquired by the operation information acquisition means,
When it is determined by the moving speed determining means that the moving speed exceeds a predetermined moving speed, and when the operation information determining means determines that the operation information has been acquired. The RFID tag communication apparatus according to claim 3, wherein the directivity control means performs control for changing the antenna to a communication directivity narrower than a current communication directivity.   The reference point setting means resets the reference point when the directivity control means controls the antenna to change to a communication directivity wider than the current communication directivity. The wireless tag communication device according to claim 2.