JP2008191734A - Non-contact communication medium reader/writer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a non-contact communication medium reader/writer eliminating an out-of-service area for a non-contact communication medium in a wide communication area, and shortening an average time required to end the communication. <P>SOLUTION: A communication area where a non-contact communication medium is located is logically divided into several small regions. Then, the antenna of a non-contact communication medium reader/writer is successively moved through a predetermined standard moving path to each region (S34), and communication with the non-contact communication medium is tried in each region (S38). The detection frequency of the non-contact communication medium in each region is calculated based on the result, and the moving path of the antenna is changed so that the antenna can be successively moved from the region whose detection frequency is the highest to each region to detect the non-contact communication medium (S36), and the antenna is moved in the sequence afterwards (S37), and the non-contact communication medium is detected. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a non-contact communication medium reader / writer that has a function of supplying power for driving to an IC tag that is a non-contact communication medium in a non-contact manner and exchanging data with the IC tag. .

  The non-contact communication medium reader / writer transmits / receives information to / from the non-contact communication medium by radio waves by bringing the non-contact communication medium close to the antenna unit, and performs non-contact read (data read) and write (data write) operations. It is a device that performs. As such a non-contact communication medium reader / writer, generally, a system that operates at a carrier frequency of 13.56 MHz is often used. In the communication at 13.56 MHz, an electromagnetic induction method is mainly used. The electromagnetic induction method is a method particularly suitable for non-contact communication with a communication distance in the near field, and uses a magnetic field generated near the antenna of the transmission / reception apparatus as a transmission medium. Since an induced electromotive force is induced on the non-contact communication medium side, it can be used as a power source. Therefore, the non-contact communication medium has a feature that a power source is unnecessary.

  In electromagnetic induction communication, a proximity type reader / writer compliant with ISO / IEC 14443, which is an international standard, or a proximity type reader / writer compliant with ISO / IEC 15693, is often used. The communication distance to be covered is about 10 cm at maximum for the proximity type and about 70 cm at maximum for the proximity type.

  Among such non-contact communication medium readers / writers, in a stationary reader / writer used for article management, checkout in a cafeteria, etc., a circular or square loop coil type provided in the non-contact communication medium reader / writer A general method is to arrange a plurality of articles, tableware, and the like with a non-contact communication medium to be communicated on the top surface of the antenna and read information transmitted by each non-contact communication medium with the antenna. In this case, in order to collectively communicate with a large number of articles and tableware, the area of the region that can be communicated at a time increases as the loop coil of the antenna becomes larger in diameter.

  However, in principle, a large-diameter loop coil antenna has a strong magnetic field strength in the vicinity of the loop coil of the antenna, and weak in the vicinity of the center of the antenna. For this reason, the non-contact communication medium placed near the center of the antenna may not be sufficiently supplied with the applied magnetic field. In this case, an area where the non-contact communication medium cannot be communicated near the center of the antenna. Is known to occur. The situation will be described with reference to FIGS. FIG. 5A is a perspective view of a general large-diameter loop coil antenna, and FIG. 5B is a graph showing magnetic field strength on a straight line passing through points A to C in FIG. 5A. It is a representation. In FIG. 5A, a one-turn loop coil 52 is provided on the upper surface of the antenna unit casing 51, and data is supplied to a non-contact communication medium (not shown) supplied with current from an external signal transmitting / receiving unit. A magnetic field is generated for replacement and power supply. The magnetic field distribution at this time is as shown in FIG.

  A point A and a point C in FIG. 5B are points on the loop coil 52 around the antenna unit housing 51 as shown in FIG. 5A, and the point B is at the center of the loop coil 52. It is a point to be located. In FIG. 5B, the magnetic field strength formed by the loop coil 52 is locally small in the vicinity of the point B, and sufficient electric power cannot be supplied to the non-contact communication medium in this region. For this reason, the central portion of the loop coil 52 becomes an area incapable of communicating with the non-contact communication medium.

  On the other hand, FIG. 6 corresponds to the case where the diameter of the loop coil in FIG. 5 is reduced, and the exclusive area of the loop coil is narrowed to a quarter of that in FIG. FIG. 6A is a perspective view of such a small-diameter loop coil type antenna. A loop coil 62 of one turn is provided on the upper surface of the antenna section housing 61. FIG. 6B is a graph showing the magnetic field intensity on a straight line passing through the points A ′ to C ′ in FIG. When a current having the same strength as in FIG. 5 is supplied from an external signal transmission / reception unit, the magnetic field strengths at points A ′ and C ′, which are points on the loop coil 62, are the same as in FIG. However, at point B ′, unlike the case of FIG. 5, the decrease in magnetic field strength is not so great. This is a feature of a small-diameter loop coil antenna, and good bidirectional communication with a non-contact communication medium can be successfully achieved in any region in the loop coil 62 including the central portion.

  As described above, it is inappropriate to configure the antenna of the non-contact communication medium reader / writer with only the large-diameter loop coil antenna because of the existence of an incommunicable region. However, when a single small-diameter loop coil antenna is used, a wide communicable area cannot be obtained. Therefore, a technique of using a combination of a large-diameter loop antenna and a small-diameter loop coil antenna (Patent Document 1) and sequentially moving the small-diameter loop coil antenna to a communicable area with a non-contact communication medium (Patent Document 2). Has been developed. These conventional techniques will be described below.

  Conventional examples disclosed in Patent Document 1 and Patent Document 2 will be described with reference to FIGS. 7 shows a conventional example in Patent Document 1. FIG. 7 (a) is a top view of an antenna portion of a non-contact communication medium reader / writer, and FIG. 7 (b) is an A-line in FIG. 7 (a). It is sectional drawing in A '. 7A and 7B, the antenna section includes a first loop coil antenna 72 having a large outer diameter on a substrate 71 and a second loop coil antenna 73 having a small outer diameter on the inside thereof. Both are provided. For communication with a non-contact communication medium placed in the vicinity of the center of the antenna unit, the use of the second loop coil antenna 73 having a small outer diameter provides an effect of eliminating an area where communication is not possible. In FIG. 7, the input / output signals to and from the two antennas are connected to terminals 72a, 72b, 73a, 73b provided at the ends of the substrate 71 via jumper wires 74 and conductor patterns 75, 76, and the antenna externals. Has been led to.

  On the other hand, FIG. 8 shows a conventional example in Patent Document 2, in which an antenna 81, which is a loop coil type single antenna with a small outer diameter, is mounted on an antenna carrier 82 and driven on a rail 84 by driving a motor 83. Move freely. The rail 84 is also fixed to the rail carrier 85 and can be similarly moved on the rail 87 by driving the motor 86. Therefore, the antenna 81 can be freely moved within the range of the rail 84 and the rail 87 to a position where communication with the non-contact communication medium can be performed by a command from the host device.

Japanese Patent Laid-Open No. 2004-70648 JP 2006-260036 A

  However, in the method disclosed in Patent Document 1, a non-contact communication medium reader / writer requires a plurality of large-diameter and small-diameter antennas. Therefore, a circuit for switching high-frequency power supplied to the plurality of antennas, and There was a problem that the control method was complicated. On the other hand, in the method disclosed in Patent Document 2, the antenna is moved along the same route every time communication is successful regardless of the position of the non-contact communication medium. The average time required for successful communication becomes longer. Moreover, there is a problem that the required time cannot be shortened even if the number of communications is repeated.

  Therefore, the present invention secures a wide planar communication area, eliminates an area where communication with a non-contact communication medium is impossible, and can reduce the average time required for the end of communication. An object of the present invention is to provide a non-contact communication medium reader / writer with a simple configuration and control method.

  In order to solve the above-described problems, the present invention provides a non-contact communication medium reader / writer in which a single small-diameter loop coil antenna disclosed in Patent Document 2 is used to move the antenna in a plane. The procedure for moving the antenna to a position where communication with the non-contact communication medium can be performed is changed using the above configuration, and the time required until the communication of the non-contact communication medium is completed is shortened.

  In a specific application of a non-contact communication medium reader / writer, such as article management or settlement at a restaurant, the position where the non-contact communication medium is placed is not random and often has a certain degree of bias. For example, let us consider a case where a small baggage is packed in a container according to a destination, and it is necessary to display a handling precaution label on the container only when the small baggage contains handling precautions. When a special IC tag is attached to a handling precaution product, if any special tag is found, the container must display a handling precaution label. It is assumed that whether there is any small package packed with a special IC tag is detected by communication with a movable antenna of a non-contact communication medium reader / writer.

  When packing a small package into a container, if the operator decides in advance to pack the item to be handled consciously into a specific place (for example, the left front corner of the container), a special IC tag is detected at that position. The probability of being intensively increased. In this case, if the detection of the IC tag performed by moving the antenna is set to start from the left front corner of the container, the average time until the detection can be shortened when a special IC tag exists. In this case, if even one special IC tag is detected, it is sufficient to determine whether or not to display a handling caution display, so that the special IC tag detection process ends at that point. When there is no special IC tag, it is necessary to move the detection antenna sequentially to all the areas in the container to detect the IC tag, and it takes a certain amount of time to obtain the result. Nevertheless, according to this method, it is possible to shorten the average time to determine whether or not it is necessary to display a display of handling precautions.

  As described above, when the position where the non-contact communication medium is placed is expected to be biased and it is desired to reduce the average time required for the detection and communication of the non-contact communication medium to be completed, the antenna described above is used. The transfer method is effective. However, if the location where the non-contact communication medium is likely to be placed is unknown, the process of calculating the effective path of the antenna by first calculating the probability of successful communication with the non-contact communication medium for each location is required. It is. When detecting and communicating with a non-contact communication medium according to this method, the process is performed as follows.

  First, the entire communication area where the non-contact communication medium is placed is logically divided into several small areas. Next, the antenna of the non-contact communication medium reader / writer is sequentially moved to each area by a predetermined standard movement path, and communication with the non-contact communication medium is attempted in each area. Even if the contactless communication medium is detected and communication is terminated at this time, the position of the antenna is not moved to the initial value, and at the start of the next communication, the movement path at the end of the previous communication The detection starts from the next antenna position.

  After detecting a predetermined number of non-contact communication media in this method, the antenna movement path is determined from the region with the highest detection frequency based on the detection frequency of the non-contact communication medium in each region. In order to detect the non-contact communication medium by moving to a region where the detection frequency is low in order, the detection is performed in that order thereafter. In the case of detection by a standard movement route, if the non-contact communication medium is detected for the first time and the detection is not finished and all the areas are moved each time, the non-contact in one trial is performed. Since the number of communication medium detections can be increased, the number of trials until a necessary amount of data is accumulated can be reduced. However, even if a non-contact communication medium is detected, the detection time required for one trial is considerably long because the trial is continued without ending.

  That is, the present invention provides an antenna moving means for moving the antenna in a non-contact communication medium reader / writer having a function of performing communication with the non-contact communication medium and supplying power to the non-contact communication medium. And storing means for storing at least one position information of the antenna when communication with the contactless communication medium is successful, and based on the position information of the one or more antennas, the contactless communication Determining one or more communication positions with a high frequency of successful communication with the medium, and determining a movement path for sequentially moving the antenna to the one or more communication positions, the antenna moving means The antenna has a function of sequentially moving the antenna to one or more of the communication positions according to the movement route determined by the route determination means. A non-contact communication medium writer.

  Further, according to the present invention, the travel route determined by the route determination means first moves to a communication position where the frequency of successful communication with the non-contact communication medium is highest, and then the frequency of successful communication is high. The non-contact communication medium reader / writer is characterized in that it goes through each communication position in order.

  Furthermore, the present invention is a contactless communication medium reader / writer, wherein the antenna is a single antenna.

  Furthermore, the present invention is a contactless communication medium reader / writer, wherein the antenna is a loop coil type antenna.

  Furthermore, the present invention is a non-contact communication medium reader / writer, wherein the antenna moving means is a stepping motor.

  Furthermore, the present invention is a non-contact communication medium reader / writer characterized in that the antenna is housed in a housing, and the antenna moves in a plane until the antenna reaches the communication position in the housing. .

  According to the present invention, since the movable small-diameter antenna is used as the antenna of the non-contact communication medium reader / writer, a wide communication area can be obtained with the non-contact communication medium. There is no area where communication is impossible. Communication with a non-contact communication medium is a communication in which the success frequency of communication with the non-contact communication medium for each communication position in the communicable region is investigated in advance, and the communication success frequency decreases from the highest communication position. It is assumed that communication is sequentially attempted by moving the antenna in order to the position. With this method, the average time until successful communication with a non-contact communication medium can be shortened compared to the conventional method, and the average time required until the end of communication with a non-contact communication medium can be reduced. It becomes.

  Hereinafter, a non-contact communication medium reader / writer according to an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is an example of a block diagram of a contactless communication medium reader / writer according to the present invention. In order to transmit / receive data to / from a non-contact communication medium, the non-contact communication medium reader / writer includes an antenna 11, a transmission / reception unit 12, and a signal processing unit 13, and a stepping motor 14 for moving the antenna. It has. Furthermore, an antenna position information storage unit 15 for storing the position of the antenna and whether or not the communication with the non-contact communication medium has succeeded at the position, a host device interface 17 for exchanging data with the host device, and A control unit 16 for controlling these functions is provided. The antenna position information storage unit 15 is configured by a nonvolatile memory so that the stored antenna position information and communication success information are retained even when the power of the non-contact communication medium reader / writer is turned off.

  FIG. 2 is a perspective view showing an example of each area when the antenna surface 21 is logically divided according to the antenna position, which is the moving area of the antenna of the contactless communication medium reader / writer according to the present invention. The antenna surface 21 is a communicable region of the non-contact communication medium reader / writer due to the movement of the antenna, and FIG. 2 shows a case where the antenna surface 21 is logically divided into nine regions depending on the antenna position. Regions are defined as region A to region I in order. When the antenna moves and is positioned at the center of each area, it is determined that bidirectional communication is possible with the non-contact communication medium existing at an arbitrary position in each area. It has been.

  FIG. 3 is an example of an operation flow of the contactless communication medium reader / writer according to the present invention. An operation example of the non-contact communication medium reader / writer will be described below with reference to FIG. When the non-contact communication medium reader / writer is turned on or receives an operation start command from the host device, the non-contact communication medium reader / writer first determines the antenna movement path (S31). Specifically, it is determined whether the number of antenna movements up to that time is N or more. N is an initial value (positive integer) predetermined by the system, and is set to 1000 times, for example. Initially, the number of times the antenna moves is naturally zero. The determination here is for deciding whether or not to return the antenna position to the initial value of the moving path at that time, and when the number of times of antenna movement is N times or more (Yes), it returns to the initial value (S32), If it is less than N times (No), the process proceeds to the next step without returning to the initial value.

  Next, it is determined again whether or not the number of antenna movements has reached N or more (S33). Here, the determination of the number of times of antenna movement is performed again when the detection of the non-contact communication medium is not completed in the later-described determination of the movement of the antenna (S43), and the antenna position is returned to the initial value of the movement path every time. This is so that there is not. When the number of antenna movements is less than N (No), an antenna movement path determined as an initial value is selected (S34), and the antenna is moved based on the movement path.

  The antenna movement path determined as the initial value may be an arbitrary path. For example, in the case of the antenna surface shown in FIG. 2, it is preferable to set the nine areas to move in the following order.

  Area A → Area B → Area C → Area D → Area E → Area F → Area G → Area H → Area I → Area A (repeated thereafter, initial value is area A)

  After the movement of the antenna, the non-contact communication medium reader / writer performs communication with the non-contact communication medium using the antenna in the area (S38), and determines whether the communication is successful (S39). When the communication is successful (Yes), the position of the antenna at that time and the communication success information at that position are stored in the position information storage unit (S40, S41), and the end of the movement of the antenna is determined (S43). . If the communication is unsuccessful (No), only the position information of the antenna is stored in the position information storage unit (S42), and the end of the movement of the antenna is similarly determined (S43). In this end determination, it is determined whether or not the processing shown in the operation flow is to be ended by an instruction of the host device or a mechanical switch. If communication with a non-contact communication medium is performed in all areas of the antenna surface, or if communication with the non-contact communication medium is successful and communication with the non-contact communication medium is not necessary any more, the antenna End the move. If not, the process returns to the determination of the antenna movement path (S33) and the process is repeated.

  When the antenna movement path has already reached N times (Yes) in the determination of the antenna movement path after the power-on of the non-contact communication medium reader / writer or the operation start command by the operation start command from the host device (S31). First, the antenna position is moved to the initial position of the moving path (S32), the antenna moving path is determined again (S33), and then it is determined whether a new antenna moving path has already been determined by the system ( S35). If a new antenna movement path has already been determined (Yes), the antenna is moved based on the path (S37), and the antenna communicates with the non-contact communication medium in the destination area. Perform (S38).

  If a new antenna movement path has not yet been determined (No), the control unit stores the antenna position information and the communication success information at the position stored in the position information storage unit by moving the antenna N times. Based on the above, the communication success probability at each position is calculated, the antenna position information is rearranged in descending order of the probability, and the order is determined as a new antenna movement path (S36). Based on this result, the process returns to determining whether a new antenna moving path has already been determined (S35). Since the moving path is naturally determined, the antenna is moved based on the new path (S37). Then, communication with the non-contact communication medium is performed (S38). Thereafter, the end of the movement of the antenna is determined (S43) through the communication success determination (S39) and the storage of the antenna position information and communication success information (S40, S41, S42). If the communication is not successful and the antenna has not yet moved all nine areas after the start of operation, the process returns to the determination of the antenna movement path (S33) without terminating the movement of the antenna. If the entire area has been moved, the movement of the antenna is terminated.

  In the case of the antenna surface shown in FIG. 2, the movement of the antenna is completed at a maximum of nine times, but the non-contact communication medium detection process itself is repeatedly performed. For example, in the case where the above-mentioned parcels are packed in containers according to destinations, and when handling non-contact communication media attached to the handling precautions are detected when the precautions are mixed in the parcel, this detection is performed while changing the container. It must be done many times. The antenna position information stored in the position information storage unit and the communication success probability at each position after the total of N detections in this way are as shown in the graph of FIG. 4, for example. FIG. 4 is a bar graph showing an example of the communication success probability in each of the nine areas of the antenna position where N = 1000. In the graph, the communication success probability is highest in region E, followed by region G, region D,. Based on this, in the case of FIG. 4, when a route is determined so that the antenna moves in descending order of the communication success probability, the new antenna moving route is determined as follows, for example.

  Region E → region G → region D → region H → region I → region F → region A → region B → region C

  This moving path is determined by the control unit of the non-contact communication medium reader / writer based on the result of N times of non-contact communication medium communication operations. Since a series of communication operations with the non-contact communication medium is finished in the last area C, the loop path from the area C to the area E is not set.

  According to this method, the non-contact communication medium reader / writer itself reads out the antenna position information accumulated in the position information storage unit and the communication success information at the position by N trials, and determines a new antenna moving path. can do. As a result, the antenna can be moved in preference to the antenna position having a high probability of successful communication with the non-contact communication medium, so that the time required for successful communication when the non-contact communication medium exists is reduced. Thus, the average time until the end of communication with the non-contact communication medium can be improved.

  The above method is effective when, for example, detecting whether or not a handling precaution is included in a small package to be packed in a container, but is also effective in managing a checkout operation in a dining room or the like. For example, a system is assumed in which IC tags are attached to dishes with dishes, the dishes selected by customers are arranged in a tray, and the checkout office performs batch payment for each tray by detecting the IC tags. In this case, there is only one kind of tray shape, and it is considered that there is a certain degree of bias in the position where customers place dishes with dishes in the tray. Can be configured to move within this range.

  If the moving path of the antenna with respect to the tray is determined by the above-described system and the antenna is moved according to the path thereafter, the average time required to detect cooked dishes can be shortened. In this case, since the checkout operation is not completed unless all the dishes are detected, it is necessary to move the entire area in the tray every time, so the time required for each checkout cannot be shortened. However, since the average time until the first tableware is detected can be shortened, if the tableware detection information is displayed at that time, it is confirmed that the checkout work is being performed smoothly for customers and workers. Notification can be made at an early stage, and an anxiety such as whether or not a malfunction has occurred in the apparatus can be eliminated. Therefore, it is effective in terms of smooth implementation of a comprehensive settlement system including customers and workers.

  In addition, in the above example such as the settlement of dishes on the tray in the cafeteria, even after N trials, the antenna moves through each of the divided areas every time. It is effective that the probability information continues to be accumulated after N trials. If the system is configured to review the antenna movement path at any time or periodically, the information after the N trials is added to the N communication success probability information and the old information is discarded in some cases. As the number of times increases, it is possible to continue to update the antenna movement path to a more optimal one. In such a system, especially when the number of divided areas where the antenna moves is very large, or the communication success probability for each area varies with the number of trials, it is sometimes necessary to review the optimal antenna movement path. This is particularly effective when

  In the above description, the antenna movement range of the contactless communication medium reader / writer according to the embodiment of the present invention is theoretically divided into a plurality of areas, and the antenna movement path between the areas is not It is for explaining the effect when it is set so as to move in order from the region where the communication success probability with the contact communication medium is high, thereby limiting the invention described in the claims or the claims It does not reduce. Moreover, each part structure of this invention is not restricted to the said embodiment, A various deformation | transformation is possible within the technical scope as described in a claim.

The example of the block diagram of the non-contact communication media reader / writer of this invention. The perspective view which shows the example of each area | region when the antenna surface is logically divided | segmented according to the antenna position in the non-contact communication media reader / writer of this invention. The example of the operation | movement flow of the non-contact communication medium reader / writer of this invention. The graph which shows the example of the communication success probability for every area | region of each antenna position of the non-contact communication media reader / writer of this invention. The figure which shows a general large diameter loop coil type | mold antenna. FIG. 5A is a perspective view of a loop coil antenna. FIG.5 (b) is a graph showing the magnetic field intensity on the straight line which passes the point A-point C of Fig.5 (a). The figure which shows the loop coil type antenna which made the aperture diameter of the antenna of FIG. 5 small. FIG. 6A is a perspective view of the loop coil antenna. FIG. 6B is a graph showing the magnetic field strength on a straight line passing through the points A ′ to C ′ in FIG. The figure which shows the structure of the antenna part of the conventional non-contact communication media reader / writer. FIG. 7A is a top view, and FIG. 7B is a cross-sectional view taken along line A-A ′ of FIG. The perspective view of the antenna part of the conventional non-contact communication medium reader / writer.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Antenna 12 Transmission / reception part 13 Signal processing part 14 Stepping motor 15 Antenna position information storage part 16 Control part 17 Host apparatus interface 21 Antenna surface 51, 61 Antenna part housing | casing 52, 62 Loop coil 71 Board | substrate 72 1st loop coil type antenna 73 Second loop coil antenna 72a, 72b, 73a, 73b Terminal 74 Jumper wire 75, 76 Conductor pattern 81 Antenna 82 Antenna carrier 85 Rail carrier 83, 86 Motor 84, 87 Rail

Claims (6)

In a non-contact communication medium reader / writer having an antenna and having a function of performing communication with a non-contact communication medium and supplying power to the non-contact communication medium,
An antenna moving means for moving the antenna;
Storage means for storing one or more pieces of position information of the antenna when communication with the non-contact communication medium is successful;
Based on the position information of the one or more antennas, determine one or more communication positions with high frequency of successful communication with the non-contact communication medium, and sequentially move the antennas to the one or more communication positions. Route determining means for determining a moving route to be
A non-contact communication medium reader / writer having a function of sequentially moving the antenna to the one or more communication positions according to the movement path determined by the path determination means by the antenna movement means. The movement route determined by the route determination means first moves to a communication position with the highest frequency of successful communication with the non-contact communication medium,
2. The non-contact communication medium reader / writer according to claim 1, wherein each of the communication positions passes through the communication in the descending order of frequency of successful communication.   The contactless communication medium reader / writer according to claim 1, wherein the antenna is a single antenna.   The contactless communication medium reader / writer according to claim 1, wherein the antenna is a loop coil antenna.   The non-contact communication medium reader / writer according to any one of claims 1 to 4, wherein the antenna moving means is a stepping motor.   6. The device according to claim 1, wherein the antenna is housed in a housing and moves in a plane until the antenna reaches the communication position in the housing. Contact communication media reader / writer.

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