RFID reader and RFID reading method

Abstract

This technology provides efficient reading of information from multiple RF tags. [Solution] The reading unit reads the information contained in the RF tag (hereinafter referred to as tag information) via the antenna unit during a set reading period. The confirmation unit confirms the status of the tag information reading by the reading unit. If the reading status confirmed by the confirmation unit does not satisfy the predetermined reading completion conditions even after the reading period has ended, the re-reading unit causes the reading unit to re-execute the reading of the tag information after the interval period has elapsed.

Description

Technical Field

[0001] This disclosure relates to a technique for non-contact reading of RFID.

Background Art

[0002] An RFID reader that non-contact reads identification information from RF tags attached to each of a large number of articles is known. RFID is an abbreviation for Radio Frequency Identification. When reading identification information from a large number of RF tags, collisions occur due to multiple RF tags responding at approximately the same timing, and interference between RF tags occurs because the RF tags interfere with each other's radiation. Such interference between RF tags causes reading omissions.

[0003] In order to read identification information from a large number of RF tags, Patent Document 1 discloses a technique for devising the arrangement of a plurality of antennas arranged within a gate, and Patent Document 2 discloses a technique for performing reading while moving an antenna.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] As the number of RF tags that need to be read at one time increases, the frequency of interference between RF tags also increases. Also, the change in the reading rate with respect to the reading time follows a saturation curve. Therefore, there has been a problem that it is difficult to achieve reading without omission in a short time only with the conventional techniques.

[0006] In particular, when it is necessary to read not only the EPC area of ​​an RF tag but also the TID area and USER area, the time required to read each RF tag increases, interference between RF tags due to collisions etc. becomes more likely, and the difficulty increases. The EPC is the area that stores code information for identifying the RF tag. The TID is the area written by the manufacturer when the RF tag is manufactured. The USER area is an area where the user can freely read and write data.

[0007] One aspect of this disclosure is the provision of a technology for efficiently reading information from multiple RF tags. [Means for solving the problem]

[0008] One aspect of the present disclosure is an RFID reader comprising an antenna unit, a reading unit, a verification unit, and a re-reading unit. The antenna unit is configured to transmit and receive radio waves for reading tags. The reading unit is configured to read information contained in an RF tag (hereinafter referred to as tag information) via the antenna unit for a set reading period. The verification unit is configured to verify the status of tag information reading by the reading unit. The re-reading unit is configured to cause the reading unit to re-execute the reading of tag information after an interval period has elapsed, if the reading status confirmed by the verification unit does not satisfy the predetermined reading completion conditions even after the reading period has ended.

[0009] With this configuration, if the condition for completion of reading the tag information is met, the reading process is immediately terminated, and if the condition for completion is not met, the reading process is restarted, thus enabling efficient reading of tag information.

[0010] In one aspect of this disclosure, the interval period may be set to the length required for an RF tag that has responded to a tag-reading radio wave to become capable of responding again after the irradiation of the tag-reading radio wave is interrupted. In this case, even if the reading-related states between the RFID reader and the RF tag differ due to an error during reading, the internal state of the RF tag is reset during the interval period. Therefore, during re-reading, reading can be performed on all RF tags, and the reading rate can be improved.

[0011] In one aspect of this disclosure, the re-reading unit may use a read completion condition set to include the read rate, which is the percentage of RF tags to be read in which tag information has been successfully read, being equal to or greater than a threshold. In this case, the method of terminating the read process can be flexibly changed depending on the purpose of reading the tag information.

[0012] In one aspect of this disclosure, the re-reading unit may terminate the reading of tag information when the number of re-reads, which is the number of times the reading unit has been made to re-execute the reading, reaches a predetermined number. In this case, it is possible to prevent the tag reading processing time from being unnecessarily prolonged.

[0013] In one aspect of this disclosure, the antenna unit may include a plurality of antenna units, each independently controlled for transmitting and receiving radio waves for tag reading. In this case, since the reading environment differs for each antenna unit, the reading rate can be improved compared to when reading is performed with a single antenna unit.

[0014] In one aspect of this disclosure, multiple antenna units may be mixed together, each transmitting and receiving with different polarizations. In this case, the reading environment for each antenna unit can be further varied.

[0015] In one aspect of this disclosure, at least one of the multiple antenna units may be arranged such that the direction of radio wave irradiation differs from that of the other antenna units. In this case, the number of RF tags that are blocked by articles and whose radio waves for tag reading cannot reach can be reduced.

[0016] In one aspect of this disclosure, the reading unit may change the combination of antenna units used with each re-read. In this case, the variations in the reading environment that differ with each re-read can be increased.

[0017] In one aspect of this disclosure, at least one of the multiple antenna units may be a movable antenna whose position or orientation changes according to instructions from the reading unit. The reading unit may change the position or orientation of the movable antenna during reading or with each subsequent reading. In this case, the variations in the reading environment that differ with each subsequent reading can be further increased.

[0018] In one aspect of this disclosure, at least one of the multiple antenna units may be a handheld antenna. In this case, by using a handheld antenna, the operator can emit radio waves for tag reading from any distance or angle.

[0019] One aspect of this disclosure may further include a structure that forms a storage space for accommodating articles to which RF tags are attached, and has an opening for inserting and removing articles from the storage space. At least one of a plurality of antenna units may be provided on the structure to transmit radio waves toward the storage space and receive radio waves arriving from the storage space. In this case, tag information can be read within the storage space of the structure.

[0020] In one aspect of this disclosure, at least a portion of the surface of an opening or closing body provided in a structure and an opening to open and close the opening, on the side facing the storage space, may be provided with a reflective layer that reflects radio waves. In this case, leakage of tag-reading radio waves to the outside of the storage space can be suppressed, and the reflection of tag-reading radio waves within the storage space allows the RF tag to be irradiated with tag-reading radio waves from a wider variety of directions.

[0021] One aspect of the present disclosure is an RFID reading method. The RFID reading method includes a step of reading information (hereinafter referred to as tag information) possessed by an RF tag through an antenna unit configured to transmit and receive radio waves for tag reading during a set reading period. The RFID reading method also includes a step of checking the reading status of the read tag information. Further, the RFID reading method includes a step of re-executing the reading of tag information through the antenna unit after the elapse of an interval period when the confirmed reading status does not satisfy the determined reading completion condition even after the reading period ends.

[0022] By executing such a method, if the tag information reading completion condition is satisfied, the reading is immediately terminated, and if the reading completion condition is not satisfied, the reading is re-executed, so that the tag information can be efficiently read.

Brief Description of the Drawings

[0023] [Figure 1] It is a perspective view showing the appearance of an RFID reading device. [Figure 2] It is a functional configuration diagram of an RFID reading device. [Figure 3] It is an explanatory diagram showing the arrangement of each part on the left side wall and the arrangement of unit antennas in the side antenna unit. [Figure 4] It is an explanatory diagram showing the arrangement of unit antennas in the right side antenna unit. [Figure 5] It is an explanatory diagram showing the arrangement of unit antennas in the top surface antenna unit. [Figure 6] It is a perspective view showing the appearance of a racket antenna. [Figure 7] It is a flowchart of a reading process executed by a reader / writer. [Figure 8] It is a list showing the combination of antenna units used in each reading phase, etc. [Figure 9] It is a graph showing the relationship between the reading time in the first phase and the average number of readings alone in the first phase. [Figure 10]This graph shows the relationship between the operating time of the second phase and the average number of pages read during the second phase alone. [Figure 11] This graph shows the relationship between the downtime in the second phase and the average number of pages read during the second phase alone. [Figure 12] This graph shows the relationship between the interval time between Phase 1 and Phase 2 and the average number of pages read during Phase 2 alone. [Figure 13] This graph shows the relationship between the interval time between Phase 1 and Phase 2 and the average number of pages read in total for both Phase 1 and Phase 2. [Modes for carrying out the invention]

[0024] Embodiments of this disclosure will be described below with reference to the drawings.

[0025] [1. Structure] The RFID reader 1 shown in Figure 1 includes a gate-shaped structure (hereinafter referred to as "gate") 10 that forms a storage space for storing articles. The RFID reader 1 communicates with RF tags attached to articles stored in the storage space and reads tag information (i.e., RFID) from the RF tags. The RF tag is a passive tag equipped with a semiconductor chip and an antenna. The RFID and a flag are stored in the semiconductor chip of the RF tag. The RFID is information for individually identifying an article to which an RF tag is attached (hereinafter referred to as "target article"). The flag is information indicating whether the RFID has already been read (hereinafter referred to as "flag A") or has not yet been read (hereinafter referred to as "flag B").

[0026] Gate 10 is a tunnel-type gate having a rectangular tubular wall with openings at both ends and a hollow interior. The containment space formed by gate 10 is large enough for a worker to enter and exit, for example, while standing, along with a cart loaded with goods. The rectangular tubular wall of gate 10 comprises two opposing side walls 11 and 12, a ceiling 13, and a floor 14 opposite the ceiling 13.

[0027] Here, the direction perpendicular to the opening surface of the gate 10, that is, the direction in which articles are inserted into and removed from the gate-like structure, is defined as the front-to-back direction. The direction perpendicular to the ceiling 13 and floor 14 is defined as the up-and-down direction, and the direction perpendicular to the side walls 11 and 12 is defined as the left-to-right direction. However, the left-to-right direction is defined as viewed from the front, with side wall 11 also referred to as the left-side wall and side wall 12 as the right-side wall.

[0028] Of the openings of the gate 10, a shield curtain 15 is installed in the front opening, and a double-opening shield door 16, which is configured to open and close freely, is installed in the rear opening. The shield curtain 15 is attached to a curtain rail 131 provided above the front opening of the gate 10. The shield door 16 is equipped with a window 161 that allows the interior to be seen from the outside when the shield door 16 is closed. The shield curtain 15 and the shield door 16 are equipped with a reflective layer made of a material that reflects electromagnetic waves. The window 161 is made of a transparent material such as acrylic or glass, and a transparent film is attached to the surface of the window 161 to suppress the leakage of electromagnetic waves to the outside through the window 161. This film may have any of the following functions: reflecting electromagnetic waves, absorbing electromagnetic waves, or shielding electromagnetic waves.

[0029] The side walls 11, 12 and the ceiling 13 are constructed by assembling an outer wall material that forms the outer surface of the gate 10 and an inner wall material that faces the containment space formed by the gate 10 onto a framework made of a metal frame. A space is formed between the outer wall material and the inner wall material, and the antenna section 2, etc., which will be described later, is arranged in this space.

[0030] Exterior wall materials are made of materials that have the function of blocking radio waves (for example, metal). Interior wall materials are made of materials that have the function of transmitting radio waves and materials that have the function of reflecting radio waves.

[0031] For example, the floor 14 may be made of the same material as the exterior wall material described above.

[0032] The metal frame and exterior wall material that make up the gate 10 are assembled so that they are electrically conductive to each other.

[0033] As shown in Figure 2, the RFID reader 1 comprises an antenna unit 2, an antenna drive unit 3, a reader / writer 4, and a terminal device 5. The RFID reader 1 may also include an antenna hub 6 and a switch hub 7.

[0034] The antenna unit 2 transmits and receives radio waves for tag reading according to instructions from the reader / writer 4. The antenna unit 2 comprises a left-side antenna unit 21, a right-side antenna unit 22, a top-side antenna unit 23, and a racket antenna 24. Hereafter, each part of the antenna unit 2 will also be referred to as antenna units 21 to 24. Antenna units 21 to 24 are configured to independently control the transmission and reception of radio waves for tag reading.

[0035] As shown in Figure 3, the left side antenna unit 21 is positioned in the space between the outer wall material and the inner wall material of the left side wall 11. Figure 3 shows the left side wall 11 with the inner wall material removed.

[0036] The left side antenna unit 21 comprises four unit antennas 211 to 214. Each of the unit antennas 211 to 214 is a rectangular planar antenna configured to transmit and receive right-hand circularly polarized waves. The unit antennas 211 to 214 are formed on a metal plate 215 that is mounted on the left side wall 11 so as to be movable in the vertical direction. That is, by moving the metal plate 215, the four unit antennas 211 to 214 are configured to move vertically while maintaining their arrangement.

[0037] Unit antenna 211 is positioned near the center of the metal plate 215. Unit antenna 212 is positioned above unit antenna 211. Unit antennas 213 and 214 are positioned below unit antenna 211, aligned in the front-to-back direction.

[0038] The right-side antenna unit 22 is positioned in the space between the outer and inner wall materials of the right-side wall 12 of the gate 10. As shown in Figure 4, the right-side antenna unit 22 comprises two unit antennas 221 and 222. Both unit antennas 221 and 222 are rectangular planar antennas configured to transmit and receive horizontally polarized waves. The unit antennas 221 and 222 are positioned side by side in the front-to-back direction below the right-side wall 12, i.e., near the floor 14. The metal frame structure is not shown in Figure 4.

[0039] The top antenna unit 23 is positioned on the ceiling 13 of the gate 10. As shown in Figure 5, the top antenna unit 23 comprises four unit antennas 231 to 234. Unit antennas 231 to 234 are all rectangular planar antennas configured to transmit and receive right-hand circular polarization. Unit antennas 231 and 232 are positioned in the front-to-back direction, with the center of the ceiling 13 in between. Unit antennas 233 and 234 are positioned in the left-to-right direction, with the center of the ceiling 13 in between. In Figure 5, as in Figure 4, the metal frame structure is not shown.

[0040] The left side antenna unit 21, the right side antenna unit 22, and the top antenna unit 23 are configured to transmit radio waves to the entire housing space and to receive radio waves arriving from the housing space.

[0041] As shown in Figure 6, the racket antenna 24 has a rectangular planar antenna 241 configured to transmit and receive right-hand circularly polarized waves, with a handle 242 attached. The racket antenna 24 is positioned at any location within or outside the housing space so that it can be picked up and used by an operator. For example, as shown in Figures 1 and 3, a holder 17 may be attached to the left side wall 11 in the area where the inner wall material has been removed, and the racket antenna 24 may be held in this holder 17.

[0042] Thus, the racket antenna 24 is configured to have a mixture of antennas with different polarizations for transmission and reception.

[0043] As shown in Figure 3, the antenna drive unit 3, reader / writer 4, terminal device 5, and antenna hub 6 are housed in the space formed between the outer and inner wall materials of the left side wall 11, similar to the left side antenna unit 21.

[0044] The antenna drive unit 3 is an electric actuator that moves the metal plate 215 of the left side antenna unit 21 vertically according to instructions from the reader / writer 4.

[0045] The reader / writer 4 consists of a microcomputer including a CPU, ROM, RAM, etc. The reader / writer 4 also features four antenna connection ports P1-P4, a general-purpose input / output port P5 (GPIO), and a communication port P6. GPIO stands for General Purpose input / output.

[0046] Antenna ports P1 to P4 are connected to the antenna hub 6, two unit antennas 221 and 222 belonging to the right-side antenna unit 22, and the racket antenna 24.

[0047] The antenna hub 6 has 8 ports. Each port of the antenna hub 6 is connected to one of the four unit antennas 211-214 belonging to the left side antenna unit 21, and one of the four unit antennas 231-234 belonging to the top antenna unit 23.

[0048] The antenna drive unit 3 is connected to the general-purpose input / output port P5.

[0049] The communication port P6 is connected to a switch hub 7 located outside the RFID reader 1. The switch hub 7 may be integrated with the RFID reader 1. The reader / writer 4 is connected to the terminal device 5 and the management server 8 via the switch hub 7, forming a local area network with the terminal device 5 and the management server 8.

[0050] The reader / writer 4 performs at least the tag reading process and the main process. The tag reading process is the reader / writer 4's primary process, which involves extracting the RFID from the signal received via the antenna unit 2 and comparing it with information about the target item stored in the management server 8 (hereinafter referred to as the target item list). The main process is the process of starting and stopping the tag reading process in conjunction with the control of the antenna unit 2 and the antenna drive unit 3.

[0051] The RAM of the reader / writer 4 is provided with at least an area for storing the detection history of each target item by the reader / writer 4.

[0052] The terminal device 5 has a function for inputting instructions to the reader / writer 4 and a function for displaying the processing results from the reader / writer 4, and a portable terminal such as a tablet may be used. The part of the inner wall material facing the terminal device 5, which is located in the left wall 11, may have a hole for operating the screen of the terminal device 5 and checking the information displayed on the screen. In addition, the terminal device 5 may be positioned so that it can be picked up and used by an operator, similar to the racket antenna 24.

[0053] [2. Tag reading process] The tag reading process is started and stopped by instructions from the main process, which will be described later.

[0054] In the tag reading process, only RF tags with flag A perform RFID reading in an operating mode that responds to the tag reading radio waves. Furthermore, after changing to flag B, the RF tag is configured to maintain flag B while receiving the tag reading radio waves, and if reception of the tag reading radio waves is interrupted, it maintains flag B for more than 2 seconds before changing to flag A.

[0055] Since the tag reading process is an existing process, further explanation will be omitted here.

[0056] [3. Main Processing] The main processing performed by the reader / writer 4 will be explained using the flowchart in Figure 7.

[0057] When an operator uses the RFID reader 1 to perform a task, they first place the item to be stored, which is the item to which the RF tag is attached, into the storage space, cover the front opening with the shield curtain 15, and close the rear opening with the shield door 16. Next, the operator operates the terminal device 5 to input a command to start reading. When the reader / writer 4 receives the command to start reading from the terminal device 5, it starts the main processing.

[0058] When the main processing starts, in S110, the reader / writer 4 performs initialization processing. Specifically, the reader / writer 4 moves the metal plate 215 of the left side antenna unit 21 to its initial position (for example, the lower end of the movable range). It also initializes the parameter i, which identifies the measurement phase, to 1.

[0059] In this embodiment, the measurement phase consists of three phases (i.e., phase number N=3). The combination and method of use of the antenna units 21-24 differ for each measurement phase. In other words, the irradiation environment for the radio waves used for tag reading is changed for each measurement phase, and RFID reading is repeated.

[0060] As shown in Figure 8, in the first phase, reading is performed using the top antenna unit 23, the right side antenna unit 22, and the left side antenna unit 21 simultaneously. However, the left side antenna unit 21 is stationary in its initial position, i.e., at the lower end of the movable range, while the measurement is performed. The first phase also consists of a single reading period (e.g., 30 seconds) during which the tag reading process is executed. The completion of this reading period is the condition for the end of the first phase. The number of phase repetitions for the first phase is set to 1.

[0061] In the second phase, reading is performed using only the left-side antenna unit 21. The second phase consists of an upward period, a stop period, and a downward period. The upward period is the period during which the tag reading process is performed while the metal plate 215 moves from the lower end to the upper end of the movable range. The stop period is the period during which the transmission of radio waves for tag reading, and consequently the tag reading process, is stopped. The downward period is the period during which the tag reading process is performed while the metal plate 215 moves from the upper end to the lower end of the movable range. In other words, in the second phase, the vertical position of the left-side antenna unit 21 is changed while the tag reading process is being performed. The length of the upward period and the downward period are set to, for example, 11 seconds each, and the length of the stop period is set to, for example, 2 seconds. The completion of the upward period, stop period, and downward period constitutes the phase termination condition for the second phase. The number of phase repetitions for the second phase is set to 1.

[0062] In the third phase, only the racket antenna 24 is used, and the operator holds the racket antenna 24 in their hand and moves it freely to perform the reading. The third phase consists of one work period (for example, 60 seconds) in which the tag reading process is executed. The completion of this work period is the condition for the end of the third phase. The number of repetitions for the third phase is 1.

[0063] Returning to Figure 7, in S120, the reader / writer 4 drives the antenna unit 2 and starts the tag reading process in the i-th phase setting. During the tag reading process, the reader / writer 4 stores the information contained in the response from the RF tag (hereinafter referred to as the read information) in memory.

[0064] In S130, the reader / writer 4 checks the RFID reading status for the target item by comparing the reading information stored in memory with the list of target items stored in the management server 8.

[0065] In S140, the reader / writer 4 determines whether the RFID reading completion condition is satisfied for all the articles shown in the target article list. If the reading completion condition is satisfied, the process proceeds to S150; if not, the process proceeds to S160. The reading completion condition uses the fact that the reading rate, which is the ratio of successfully read RF tags (i.e., target articles) among the tags to be read, is equal to or higher than a threshold value. Here, 100% is used as the threshold value. However, the threshold value may be set to less than 100%.

[0066] In S150, the reader / writer 4 stops the tag reading process and advances the process to S220.

[0067] In S160, the reader / writer 4 determines whether the phase end condition for the i-th phase is satisfied. If the reader / writer 4 determines that the phase end condition is satisfied, the process proceeds to S170; if it determines that the phase end condition is not satisfied, the process returns to S130 to continue the tag reading process in the i-th phase.

[0068] In S170, the reader / writer 4 stops the tag reading process.

[0069] In S180, the reader / writer 4 determines whether the number of executions of the tag reading process in the i-th phase has reached the set number of phase repetitions. If it has reached the number of repetitions, the process proceeds to S190; if not, the process proceeds to S210.

[0070] In S190, the reader / writer 4 determines whether the parameter i is the same as the prepared number of phases N. If i = N, the process proceeds to S220; if i < N, the process proceeds to S200.

[0071] In S200, the reader / writer 4 increments the parameter i that identifies the measurement phase by 1 and advances the process to S210.

[0072] In S210, the reader / writer 4 waits for a predetermined interval period and then returns to processing in S120. In other words, after the interval period has elapsed, the tag reading process is re-executed.

[0073] In S220, the reader / writer 4 notifies the terminal device 5 of the result of the tag reading process and terminates the main process. If via S150, it notifies that the RFID was successfully read from the RF tag for all items; if via S200, it notifies that there were items for which reading failed.

[0074] [4. Setting the period] The length of the measurement period used as the termination condition for the first phase, the lengths of the rising period, stopping period, and falling period used as the termination condition for the second phase, the length of the work period used as the termination condition for the third phase, and the length of the interval period inserted at the transition between each phase may be determined experimentally.

[0075] Figure 9 is a graph showing the relationship between the length of the reading period (hereinafter referred to as reading time) and the average number of items read when only the tag reading process in Phase 1 is performed. The number of target items was set to 2000. The same applies to the following measurements. In this case, the graph forms a saturation curve, and the number of items read reaches approximately its upper limit at a reading time of about 30 seconds. Even if the reading time is extended further, the average number of items read does not change significantly. From the results in Figure 9, the measurement period for Phase 1 can be set to, for example, 30 seconds.

[0076] Figure 10 is a graph showing the relationship between operational time and the average number of tags read when only the tag reading process in Phase 2 is performed. Operational time is the length of the rising and falling periods, and the rising and falling periods were set to the same length. In Figure 10, the number of tags read is highest when the operational time is set to 11-12 seconds.

[0077] Figure 11 is a graph showing the relationship between the stop time (i.e., the length of the stop period) and the average number of sheets read, with the operating time of the second phase set to 11 seconds. The stop time is the time from when the left side antenna unit 21 completes to when it starts to descend, during the driving of the left side antenna unit 21 via the metal plate 215 by the antenna drive unit 3. In Figure 11, the number of sheets read is highest when the stop time is set to 2 seconds.

[0078] Based on the results in Figures 10 and 11, the length of the upward and downward phases (i.e., the operating time) in the second phase may be set to, for example, 11 seconds, and the length of the stopping period may be set to, for example, 2 seconds.

[0079] Figure 12 is a graph showing the interval time (i.e., the length of the interval period) between the completion of the tag reading process in Phase 1 and the start of the tag reading process in Phase 2, and the results of measuring the average number of tags read in Phase 2 alone. Figure 13 is a graph showing the interval time and the results of measuring the average number of tags read combined in Phases 1 and 2. The lengths of the reading period, rising period, stop period, and falling period used in Phases 1 and 2 were set based on the results in Figures 9 to 11. Specifically, for Phase 1, the length of the measurement period was set to 30 seconds. For Phase 2, the lengths of the rising and falling periods were both set to 11 seconds, and the length of the stop period was set to 2 seconds. From the results in Figure 12, the length of the interval period may be set to, for example, 2 seconds.

[0080] The interval period should basically be set to the time required for the RF tag with flag B to return to flag A after the transmission of the tag reading radio waves is interrupted (hereinafter referred to as the recovery time), that is, the length of time required before it can respond again. However, only a lower limit is specified for the recovery time, and the actual length will vary depending on the RF tag product. Therefore, the interval period may be determined by experiments as described above to ensure that it is the minimum necessary time.

[0081] [5. Correspondence of Terms] In this embodiment, the tag reading process, which is started in S120 and stopped in S150 or S170, corresponds to the reading unit of the present disclosure. In this embodiment, S130 corresponds to the verification unit of the present disclosure, and S160 to S210 correspond to the re-reading unit of the present disclosure. In this embodiment, the left side antenna unit 21 corresponds to the movable antenna of the present disclosure, and the racket antenna 24 corresponds to the handheld antenna of the present disclosure. In this embodiment, the shield curtain 15 and shield door 16 correspond to the opening and closing bodies of the present disclosure. In this embodiment, the number of phases N corresponds to the specified number of re-readings of the present disclosure. In this embodiment, the combined period of the rising period, stopping period, and descending period in the second phase, and the work period in the third phase, correspond to the reading period of the present disclosure.

[0082] [6. Effects] The embodiments described in detail above produce the following effects.

[0083] (6a) The RFID reader 1 has multiple reading phases with different usage patterns for antenna units 21 to 24. If the phase termination condition is met without satisfying the reading completion condition, the reading phase is switched and the tag reading process is repeated. Furthermore, the polarization and irradiation direction of the radio waves for tag reading are set to be different for each of the antenna units 21 to 23, and the antenna unit (i.e., racket antenna) 24 is configured to irradiate RFID radio waves from any position and in any direction. Therefore, since the reading conditions such as the relative position between the antenna units 21 to 24 and the target item change with each measurement phase, the RFID reading rate can be improved.

[0084] (6b) When switching reading phases, RFID reader 1 inserts an interval period during which it does not emit radio waves for tag reading, so that the RF tag flag is reset during the interval period. Therefore, even if an RF tag is flag B in the target item list despite being marked as unreadable due to an error during reading in the previous reading phase, all RF tags can be made to respond in the next reading phase, thereby improving the reading rate.

[0085] (6c) RFID reader 1 is configured to terminate the process by notifying the reader that the reading failed if the tag reading process has not been completed in the three provided reading phases but the reading completion conditions have not been met. This prevents the tag reading process from being repeated unnecessarily.

[0086] (6d) When RFID reading is performed in the RFID reader 1, the opening of the gate 10, which is provided for putting the target item in and out of the storage space, is electrically sealed by a shield curtain 15 and a shield door 16 that reflect radio waves. Therefore, it is possible to prevent RFID from being read from RF tags located near the outside of the gate 10. In addition, the radio waves for tag reading emitted from the antenna units 21 to 24 are reflected within the storage space, so that the radio waves for tag reading can be irradiated onto the RF tags from a wider variety of directions. In other words, it is possible to reduce the number of RF tags that are blocked from receiving the radio waves for tag reading by other RF tags.

[0087] [7. Other Embodiments] Although embodiments of the present disclosure have been described above, the present disclosure is not limited to the embodiments described above and can be implemented in various modified forms.

[0088] (7a) In the above embodiment, a shield curtain 15 and a shield door 16 are provided at the opening of the gate 10, but a wall surface may be provided at either the opening of the gate 10 instead of the shield curtain 15 or the shield door 16. In other words, the gate 10 may have a structure in which people enter the accommodation space from one direction and exit from the same direction.

[0089] (7b) In the above embodiment, the left side antenna unit 21 is configured to be movable in the vertical direction, but the radiation direction may be changed by tilting the radiating surfaces of the unit antennas 211 to 214. Furthermore, not limited to the left side antenna unit 21, any one, any two, or all of the antenna units 21 to 23 may be configured to be movable. Also, the direction of movement of the movable antenna units is not limited to the vertical direction, but may be moved in any direction. In addition, for each antenna unit 21 to 23, the directivity of the antenna units 21 to 23 may be electrically controlled by controlling the phase difference of the signals supplied to the multiple unit antennas constituting the antenna unit 21 to 23.

[0090] (7c) In the above embodiment, three reading phases (i.e., the first to third phases) are provided, but the number of reading phases may be two or four or more. Also, although the number of phase repetitions for each reading phase is set to one, the number of phase repetitions may be set to two or more to repeat the same reading phase multiple times.

[0091] (7d) The usage patterns of antenna units 21 to 24 in each reading phase are not limited to the example shown in Figure 8, and should be set appropriately to shorten the reading time depending on the operating environment and the characteristics of the RF tag used.

[0092] (7e) Multiple functions of one component in the above embodiment may be realized by multiple components, or one function of one component may be realized by multiple components. Also, multiple functions of multiple components may be realized by one component, or one function realized by multiple components may be realized by one component. Furthermore, some of the configurations of the above embodiment may be omitted. Furthermore, at least some of the configurations of the above embodiment may be added to or replaced with the configurations of other above embodiments.

[0093] (7f) In addition to the RFID reader 1 described above, the disclosure can also be implemented in various forms, such as a system comprising the RFID reader 1, a program for causing a computer to function as a reader / writer 4 of the RFID reader 1, a non-transitional physical recording medium such as a semiconductor memory on which this program is recorded, and an RFID reading method.

[0094] [8. The technical concept disclosed herein] [Item 1] An antenna unit configured to transmit and receive radio waves for reading RF tags, A reading unit configured to read information contained in the RF tag (hereinafter referred to as tag information) via the antenna unit during a set reading period, A confirmation unit configured to confirm the status of the tag information reading by the reading unit, Even after the aforementioned reading period has ended, if the reading status confirmed by the confirmation unit does not satisfy the predetermined reading completion conditions, a re-reading unit is configured to cause the reading unit to re-execute the reading of the tag information after the interval period has elapsed. An RFID reader equipped with [a specific feature].

[0095] [Item 2] The RFID reader described in item 1, The interval period is set to the length of time required for the RF tag that has responded to the tag reading radio wave to become capable of responding again after the irradiation of the tag reading radio wave is interrupted. RFID reader.

[0096] [Item 3] An RFID reader as described in item 1 or item 2, The re-reading unit uses the read completion condition, which is set to include the fact that the read rate, which is the percentage of RF tags to be read in which the tag information has been successfully read, is equal to or greater than a threshold. RFID reader.

[0097] [Item 4] An RFID reader described in any one of items 1 to 3, The re-reading unit terminates reading the tag information when the number of re-reads, which is the number of times the reading unit has been prompted to re-execute the reading process, reaches a predetermined number. RFID reader.

[0098] [Item 5] An RFID reader described in any one of items 1 to 4, The antenna section comprises a plurality of antenna units, each independently controlled for transmitting and receiving the radio waves for tag reading. RFID reader. [Item 6] The RFID reader described in item 5, The aforementioned multiple antenna units include a mixture of units that transmit and receive with different polarizations. RFID reader. [Item 7] An RFID reader as described in item 5 or item 6, At least one of the plurality of antenna units is arranged such that the direction of radio wave irradiation is different from that of the other antenna units. RFID reader. [Item 8] An RFID reader described in any one of items 5 through 7, The reading unit changes the combination of antenna units used each time it re-reads. RFID reader. [Item 9] An RFID reader described in any one of items 5 through 8, At least one of the aforementioned multiple antenna units is a movable antenna whose position or orientation changes according to instructions from the reading unit. The reading unit changes the position or orientation of the movable antenna during reading or each time it is read again. RFID reader. [Item 10] An RFID reader described in any one of items 5 through 9, At least one of the aforementioned multiple antenna units is a handheld antenna. RFID reader. [Item 11] The RFID reader described in item 5, The structure further comprises a storage space for accommodating an article to which the RF tag is attached, and an opening for inserting and removing the article from the storage space. At least one of the plurality of antenna units is provided on the structure to transmit radio waves toward the accommodation space and to receive radio waves arriving from the accommodation space. RFID reader. [Item 12] The RFID reader described in item 11, At least a portion of the surface of the structure and the opening / closing body provided in the opening to open and close the opening is provided with a reflective layer that reflects radio waves. RFID reader. [Item 13] The process involves reading the information contained in the RF tag (hereinafter referred to as "tag information") for a set reading period via an antenna unit configured to transmit and receive radio waves for tag reading, and A step to confirm the reading status of the tag information that has been read, If, even after the aforementioned reading period has ended, the confirmed reading status does not satisfy the predetermined reading completion conditions, the process includes the step of re-executing the reading of the tag information via the antenna unit after the interval period has elapsed. RFID reading method including [Explanation of Symbols]

[0099] 1...RFID reader, 2...Antenna unit, 3...Antenna drive unit, 4...Reader / writer, 5...Terminal device, 6...Antenna hub, 7...Switch hub, 8...Management server, 10...Gate-shaped structure (gate), 11...Left wall, 12...Right wall, 13...Ceiling, 14...Floor, 15...Shield curtain, 16...Shield door, 17...Holder, 21...Left side antenna unit, 22...Right side antenna unit, 23...Top antenna unit, 24...Racket antenna, 131...Curtain rail, 161...Window, 211~214, 221, 222, 231~234...Unit antenna, 215...Metal plate, 241...Planar antenna, 242...Handle, P1~P4...Antenna connection port, P5...General-purpose input / output port, P6...Communication port.

Claims

1. An antenna unit configured to transmit and receive radio waves for tag reading, A reading unit configured to read information contained in the RF tag (hereinafter referred to as tag information) via the antenna unit during a set reading period, A confirmation unit configured to confirm the status of the tag information reading by the reading unit, Even after the aforementioned reading period has ended, if the reading status confirmed by the confirmation unit does not satisfy the predetermined reading completion conditions, a re-reading unit is configured to cause the reading unit to re-execute the reading of the tag information after the interval period has elapsed. An RFID reader equipped with [a specific feature].

2. The RFID reader according to claim 1, The interval period is set to the length of time required for the RF tag, which has responded to the tag reading radio wave, to be able to respond again after the irradiation of the tag reading radio wave has been interrupted. RFID reader.

3. The RFID reader according to claim 1, The re-reading unit uses the read completion condition, which is set to include the fact that the read rate, which is the percentage of RF tags to be read in which the tag information has been successfully read, is equal to or greater than a threshold. RFID reader.

4. The RFID reader according to claim 1, The re-reading unit terminates reading the tag information when the number of re-reads, which is the number of times the reading unit has been prompted to re-execute the reading process, reaches a predetermined number. RFID reader.

5. The RFID reader according to claim 1, The antenna section comprises a plurality of antenna units, each independently controlled for transmitting and receiving the radio waves for tag reading. RFID reader.

6. The RFID reader according to claim 5, The aforementioned multiple antenna units include a mixture of units that transmit and receive with different polarizations. RFID reader.

7. The RFID reader according to claim 5, At least one of the plurality of antenna units is arranged such that the direction of radio wave irradiation is different from that of the other antenna units. RFID reader.

8. The RFID reader according to claim 5, The reading unit changes the combination of antenna units used each time it re-reads. RFID reader.

9. The RFID reader according to claim 5, At least one of the aforementioned multiple antenna units is a movable antenna whose position or orientation changes according to instructions from the reading unit. The reading unit changes the position or orientation of the movable antenna during reading or each time it is read again. RFID reader.

10. The RFID reader according to claim 5, At least one of the aforementioned multiple antenna units is a handheld antenna. RFID reader.

11. The RFID reader according to claim 5, The structure further comprises a storage space for accommodating an article to which the RF tag is attached, and an opening for inserting and removing the article from the storage space, At least one of the plurality of antennas is provided on the structure to transmit radio waves toward the accommodation space and to receive radio waves arriving from the accommodation space. RFID reader.

12. The RFID reader according to claim 11, At least a portion of the surface of the structure and the opening / closing body provided in the opening to open and close the opening is provided with a reflective layer that reflects radio waves. RFID reader.

13. The process involves reading the information contained in the RF tag (hereinafter referred to as "tag information") for a set reading period via an antenna unit configured to transmit and receive radio waves for tag reading, and A step to confirm the reading status of the tag information that has been read, If, even after the aforementioned reading period has ended, the confirmed reading status does not satisfy the predetermined reading completion conditions, the process includes the step of re-executing the reading of the tag information via the antenna unit after the interval period has elapsed. RFID reading method including

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