Temperature control system

Abstract

When using RFID tags to manage temperature, this method suppresses variations in detected temperatures without complicating the process. [Solution] A temperature management system that manages the temperature of items stored in a storage box 10 by reading temperature information detected by RFID tags attached to the items via an antenna, comprising a reader / writer 40 that reads temperature information from RFID tags while changing the output of radio waves emitted from the antenna within a predetermined time, and a control PC 50 that manages the temperature corresponding to the temperature of the item to which the RFID tag is attached, based on the temperature value that is most frequently read from a single RFID tag within a predetermined time by the reader / writer 40.

Description

Technical Field

[0001] The present invention relates to a temperature management system.

Background Art

[0002] It is known to attach an RFID tag capable of detecting temperature information to an article stored in a storage body and manage the temperature of the article stored in the storage body. When managing the temperature using such an RFID tag, if the intensity of the radio wave radiated from the antenna is too weak to read the temperature information, the temperature information cannot be read. On the other hand, conversely, if the intensity of the radio wave is too strong, variations occur in the temperature based on the temperature information read from the RFID tag due to, for example, the radio wave being diffusely reflected within the storage body.

[0003] Here, a tag reader device that specifies the minimum output value by gradually changing the output value of the output signal for reading information from the RFID tag until the minimum output value at which information can be read from the RFID tag is disclosed in, for example, Patent Document 1.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the technology disclosed in Patent Document 1, the minimum output value is determined by gradually changing the output value of the output signal used to read information from the RFID tag until the minimum output value is reached that allows information to be read from the RFID tag. Therefore, when applying this technology to a system that uses RFID tags to manage temperature, as described above, it becomes necessary to change the output of the radio waves emitted from the antenna and process the radio wave output value required to detect the temperature accurately, which results in a complicated process.

[0006] This invention has been made in view of the problems of the conventional technology described above, and aims to provide a temperature management system that can suppress variations in detected temperature without complicating the processing when managing temperature using RFID tags. [Means for solving the problem]

[0007] To achieve the above objective, the present invention provides: A temperature management system that manages the temperature of items stored in a storage container by reading temperature information detected by an RFID tag attached to the item via an antenna, A reading means for reading the temperature information from the RFID tag while changing the output of the radio waves emitted from the antenna within a predetermined time period in order to read the temperature information, The system includes a temperature management means that manages the temperature corresponding to the most frequently read temperature information value among the temperature information values ​​read from a single RFID tag within a predetermined time period by the reading means, as the temperature of the article to which the RFID tag is attached.

[0008] In the present invention configured as described above, the reading means reads temperature information from an RFID tag attached to an article by changing the output of radio waves emitted from the antenna within a predetermined time period. The temperature management means manages the temperature corresponding to the most frequently read value among the temperature information values ​​read within the predetermined time period as the temperature of the article to which the RFID tag is attached. As a result, processing to identify the output of radio waves that can accurately detect the temperature is unnecessary, and when managing temperature using an RFID tag, variations in detected temperature can be suppressed without complicating the processing.

[0009] Alternatively, the reading means may be configured to read the temperature information while changing the frequency of the radio waves radiated from the antenna within a predetermined time period in order to read the temperature information.

[0010] In this configuration, the area within the storage container where items are kept where temperature information cannot be read from the RFID tag changes by changing the frequency, thereby improving the accuracy of temperature information reading.

[0011] Furthermore, the temperature control means may be configured to exclude values ​​of temperature information read within the predetermined time that fall outside a predetermined range from being considered as the temperature of the item.

[0012] In this configuration, the amount of processing required to determine the most frequently read temperature information value within a predetermined time is reduced.

[0013] Alternatively, the reading means may read the temperature information multiple times within the predetermined time, and the temperature management means may register the temperature corresponding to the value read most frequently within the predetermined time as a history of the item's temperature in the database at predetermined intervals.

[0014] In this configuration, it becomes easier to manage temperature changes in the items.

[0015] Furthermore, in the configuration described above, the predetermined time may be set to be changeable.

[0016] In such a configuration, temperature variations can be suppressed to control the desired temperature changes over time. [Effects of the Invention]

[0017] According to the present invention, it is unnecessary to perform processing to identify the output of radio waves emitted from the antenna that can accurately detect temperature. This makes it possible to suppress variations in detected temperature without complicating the processing when managing temperature using RFID tags.

[0018] Furthermore, in a reading device that reads temperature information by changing the frequency of radio waves emitted from an antenna within a predetermined time, the area within the storage container in which the item is stored where temperature information cannot be read from the RFID tag changes by changing the frequency, thereby improving the accuracy of temperature information reading.

[0019] Furthermore, if the temperature control means excludes values ​​outside a predetermined range from the temperature information read within a predetermined time from being considered as the temperature of the item, the amount of processing required to determine the most frequently read value among the temperature information read within the predetermined time can be reduced.

[0020] Furthermore, in a system where the reading means reads temperature information multiple times within a predetermined time, and the temperature management means registers the temperature corresponding to the most frequently read value within that time into a database as a history of the item's temperature at predetermined intervals, it becomes easier to manage changes in the item's temperature.

[0021] Furthermore, in systems where the predetermined time is adjustable, it is possible to manage the temperature change at desired intervals using a temperature with suppressed variation. [Brief explanation of the drawing]

[0022] [Figure 1] It is a diagram showing an embodiment of the temperature management system of the present invention. [Figure 2] It is a diagram showing the configuration of the storage box shown in FIG. 1. [Figure 3] It is a diagram showing a state in which an article to be managed is stored in the storage box shown in FIG. 2, (a) is a view seen from above, and (b) is a perspective view seen from the side. [Figure 4] It is a diagram showing the configuration of the RFID tag shown in FIG. 3(b), (a) is a diagram showing the laminated state, and (b) is a diagram showing the configuration of the surface of the inlet. [Figure 5] It is a block diagram showing the configuration of the reader / writer shown in FIG. 1. [Figure 6] It is a block diagram showing the configuration of the control personal computer shown in FIG. 1. [Figure 7] It is a flowchart for explaining the process when managing the temperature of an article stored in a storage box in the article management system shown in FIG. 1. [Figure 8] It is a diagram showing an example of a screen for performing various settings in the temperature management system shown in FIG. 1. [Figure 9] It is a diagram showing an example of information stored in the memory of the control personal computer. [Figure 10] It is a diagram showing an example of information regarding one RFID tag stored in the memory of the control personal computer. [Figure 11] It is a diagram showing an example of information registered in the measurement information database. [Figure 12] It is a diagram showing an example of a temperature management screen displayed on the output unit of the control personal computer. [Figure 13] It is a diagram showing the result of verifying the effect when managing the temperature information read from the RFID tag by obtaining the most frequent value. (a) is a diagram showing the temperature fluctuation over time when the algorithm is not adopted, and (b) is a diagram showing the temperature fluctuation when the algorithm is adopted. [Figure 14]This figure shows the maximum difference between the temperature information measured by a temperature sensor attached to an item and the temperature information read from an RFID tag attached to the item. [Figure 15] This block diagram shows another example of the reader / writer configuration shown in Figure 1. [Figure 16] This block diagram shows other configuration examples of the control PC shown in Figure 1. [Figure 17] This flowchart illustrates the process for managing the temperature of items stored in a storage box using the reader / writer shown in Figure 15 and the control PC shown in Figure 16. [Modes for carrying out the invention]

[0023] Embodiments of the present invention will be described below with reference to the drawings.

[0024] <Overall structure> Figure 1 shows one embodiment of the temperature control system of the present invention. Figure 2 shows the configuration of the storage box 10 shown in Figure 1, and is a view from above. Figure 3 shows the storage box 10 shown in Figure 2 with the items to be controlled stored inside, where (a) is a view from above and (b) is a perspective view from the side.

[0025] As shown in Figure 1, this embodiment includes a storage box 10, a reader / writer 40, a control PC 50, a setting information database 61, and a measurement information database 62, and manages the temperature of an item 2 (see Figure 3) using an RFID tag 20 (see Figure 3) attached to the item 2.

[0026] Storage box 10 is an example of a storage body in the present invention. As shown in Figure 2, storage box 10 has a bottom plate 11 with side plates 12a to 12d arranged upright on all four sides, and a lid 13 is rotatably attached to the side plate 12d opposite to the bottom plate 11. By rotating the lid 13 around the connection point with the side plate 11d, the space enclosed by the bottom plate 11 and the side plates 12a to 12d can be opened or closed. The bottom plate 11, side plates 12a to 12d and the lid 13 have a structure that reflects or absorbs radio waves. For example, the bottom plate 11, side plates 12a to 12d and the lid 13 may be made of a material that reflects radio waves, such as metal, or a material that reflects or absorbs radio waves may be attached to the bottom plate 11, side plates 12a to 12d and the lid 13. Furthermore, the bottom plate 11, side plates 12a to 12d, and lid 13 have a heat-insulating structure. For example, they may be made of a material that has a heat-insulating effect, such as expanded polystyrene, or a material with a heat-insulating effect may be attached to the bottom plate 11, side plates 12a to 12d, and lid 13.

[0027] Furthermore, the storage box 10 has an antenna 31 attached to the bottom plate 11 and an antenna 32 attached to the side plate 12b. Note that the antennas may be attached to only one of the bottom plate 11 or the side plate 12b, or they may also be attached to the inner surfaces of the side plates 12a, 12c, 12d and the lid 13. Increasing the number of antennas makes it easier to read information from RFID tags present inside the storage box 10.

[0028] As shown in Figure 3, an item 2 is stored in the storage box 10 configured in this way. An RFID tag 20 is attached to the item 2. Examples of items 2 include pharmaceuticals and beverages stored in bottles. In this embodiment, the temperature of the item 2, which requires strict temperature control, can be accurately managed.

[0029] The reader / writer 40, together with the antennas 31 and 32, constitutes an example of the reading means in the present invention. The reader / writer 40 is located outside the storage box 10 and is electrically connected to the antennas 31 and 32 via a cable (not shown). The reader / writer 40 emits radio waves from the antennas 31 and 32, thereby reading information from the RFID tags inside the storage box 10 in a non-contact manner via the antennas 31 and 32.

[0030] The control PC 50 is an example of a temperature control means in the present invention. The control PC 50 is electrically connected to the reader / writer 40 via a cable and manages the temperature of the items 2 stored in the storage box 10 by reading information from the RFID tags 20 attached to the items 2 stored in the storage box 10 via antennas 31 and 32 to the reader / writer 40.

[0031] <Configuration of RFID Tag 20> Figure 4 shows the configuration of the RFID tag 20 shown in Figure 3(b), where (a) shows the stacked state and (b) shows the surface configuration of the inlet 24. Note that the configuration of the RFID tag 20 shown in Figure 4 is merely an example, and other configurations are also acceptable as long as they have a temperature detection function and allow information to be read by the reader / writer 40 via antennas 31 and 32.

[0032] The RFID tag 20 is used to manage the temperature of the items 2 stored in the storage box 10. As shown in Figure 4, the RFID tag 20 is constructed by laminating adhesive layers 27a and 27b on the front and back of a strip-shaped inlet 24, and attaching a surface sheet 25 to the surface of the inlet 24 via the adhesive layer 27a.

[0033] The inlet 24 includes a base substrate 23, two antennas 22, and an IC chip 21.

[0034] The base substrate 23 is made of a non-conductive material such as a film.

[0035] The two antennas 22 are formed on one surface of the base substrate 23, with two isosceles triangular conductors arranged side by side with an air gap between them. However, the shape of the antennas 22 is not limited to this; various other shapes are conceivable, such as two strip-shaped conductors arranged in a straight line with an air gap between them, or those composed of a single conductor.

[0036] The IC chip 21 has two antenna terminals (not shown), and the side with the antenna terminals is the mounting surface. It is mounted on the side of the base substrate 23 where the antenna 22 is formed and fixed with anisotropic conductive paste (not shown). The two antenna terminals of the IC chip 21 are connected to the two antennas 22, respectively, and the anisotropic conductive paste ensures electrical conductivity between the antenna terminals and the antennas 22. The IC chip 21 operates using power obtained through contactless communication via the antennas 22. The IC chip 21 has an EPC (Electronic Product Code), which serves as the tag ID, written to it. The IC chip 21 also has a temperature detection function, and is provided with a Reserved area where the detected temperature is written and a User area where a correction value for correcting the detected temperature is written. The correction value written in the User area is for correcting the temperature detected by the IC chip 21 to the accurate temperature, and is pre-set and written during the manufacturing of the RFID tag 20 based on the temperature detected by the IC chip 21 and the accurate temperature at that time.

[0037] The RFID tag 20 configured as described above is attached to the item 2 stored in the storage box 10 by the adhesive layer 27b, as shown in Figure 3(b). The temperature information, consisting of the temperature written in the Reserved area and the correction value written in the User area, is then read by the reader / writer 40 via antennas 31 and 32, along with the EPC. Alternatively, a so-called metal-compatible tag may be used, in which a metal layer is laminated on the side of the base substrate 23 opposite to the side on which the antenna 22 is formed, so as to cover the antenna 22 in a plan view. Using a metal-compatible tag helps to suppress the reduction in the communication distance during contactless communication via antennas 31 and 32, even if the item 2 to which the RFID tag 20 is attached is made of metal.

[0038] <Configuration of Reader / Writer 40> Figure 5 is a block diagram showing the configuration of the reader / writer 40 shown in Figure 1.

[0039] As shown in Figure 1, the reader / writer 40 includes a shared unit 41, a tag data transmission processing unit 42, a digital signal conversion unit 43, a communication unit 44, a transmission level adjustment unit 45, an RF transmission unit 46, an RF reception unit 47, and a tag data reception processing unit 48.

[0040] The shared unit 41 transmits the signal output from the RF transmitter 46 as a radio signal via antennas 31 and 32, and also outputs the radio signal received by antennas 31 and 32 to the RF receiver 47.

[0041] The tag data transmission processing unit 42 outputs a signal for detecting RFID tags during polling, and also outputs a signal for reading information from the RFID tag via contactless communication.

[0042] The digital signal conversion unit 43 converts the signal output from the tag data transmission processing unit 42 into an analog signal and outputs it to the transmission level adjustment unit 45. It also converts the signal received by the RF reception unit 47 into a digital signal and outputs it to the tag data reception processing unit 48.

[0043] The communications unit 44 transmits and receives information with the control computer 50.

[0044] The transmission level adjustment unit 45 switches the output of radio waves radiated from antennas 31 and 32 via the RF transmission unit 46 for signals converted to analog signals by the digital signal conversion unit 43, by adjusting them in accordance with commands output from the control PC 50 via the communication unit 44.

[0045] The RF transmitter 46 transmits a signal whose radio wave output has been adjusted by the transmission level adjustment unit 45, on a carrier wave, via the combiner 41 and antennas 31 and 32.

[0046] The RF receiver 47 receives response signals from the RFID tag to the signal transmitted from the RF transmitter 46 via the antennas 31, 32 and the combiner 41.

[0047] The tag data receiving processing unit 48 transmits the signal, which has been converted into a digital signal by the digital signal conversion unit 43, to the control PC 50 via the communication unit 44 as information read from the RFID tag.

[0048] <Configuration of the control PC 50> Figure 6 is a block diagram showing the configuration of the control PC 50 shown in Figure 1. Note that in Figure 6, the illustration and explanation of components of the control PC 50 that are not directly related to the present invention have been omitted.

[0049] As shown in Figure 1, the control PC 50 includes a communication unit 51, a transmission level switching unit 52, a read control unit 53, a temperature control unit 54, and an output unit 55, as shown in Figure 6.

[0050] The communication unit 51 transmits and receives information with the reader / writer 40.

[0051] The transmission level switching unit 52 switches the output of the radio waves radiated from the antennas 31 and 32 by the reader / writer 40 by transmitting a command to the reader / writer 40 via the reading control unit 53 and the communication unit 51.

[0052] The reading control unit 53 transmits a command to the reader / writer 40 via the communication unit 51 to read information from the RFID tag, and also receives the information read from the RFID tag by the reader / writer 40 via the communication unit 51. Furthermore, if a command to switch the output of radio waves radiated from antennas 31 and 32 by the reader / writer 40 is output from the transmission level switching unit 52, this command is included in the command to read information from the RFID tag and transmitted to the reader / writer 40 via the communication unit 51.

[0053] The temperature control unit 54 manages the temperature of the items 2 stored in the storage box 10 based on the information received from the reader / writer 40 via the communication unit 51 by the reading control unit 53. The specific management method will be described later.

[0054] The output unit 55 consists of a display and other components, and displays and outputs the temperature and history of the item 2 managed by the temperature control unit 54.

[0055] In this embodiment, the control PC 50 is used as an example for explanation, but any control device such as a computer capable of controlling the reader / writer 40, including portable terminals, can have the above-described configuration. Alternatively, the configuration of the control PC 50 described above may be mounted on the reader / writer 40.

[0056] <Processing in the inventory management system> The following describes the process for managing the temperature of items 2 stored in storage box 10 using the temperature management system configured as described above.

[0057] Figure 7 is a flowchart illustrating the process of managing the temperature of items 2 stored in storage box 10 using the temperature management system shown in Figure 1. Note that the explanation of the polling process performed prior to reading information from RFID tags 20 by the reader / writer 40 is omitted.

[0058] First, various settings are made to control the temperature of the items 2 stored in the storage box 10 (step S1).

[0059] Figure 8 shows an example of a screen for making various settings in the temperature management system shown in Figure 1.

[0060] To perform various settings, for example, the top page of the temperature management system is displayed on the output unit 55 of the control PC 50, and the settings are specified by clicking the setting button displayed on the top page. Then, a setting screen like the one shown in Figure 8 is displayed on the output unit 55 of the control PC 50.

[0061] As shown in Figure 8, the settings screen includes, for example, an IP address input area 91, radio wave output input areas 92a and 92b, a session specification area 93, a save interval specification area 94, and an alert threshold specification area 95.

[0062] The IP address input area 91 is used to input address information for connecting to the reader / writer 40. Multiple output values ​​of radio waves emitted from antenna 31 are input in the radio wave output input area 92a, and multiple output values ​​of radio waves emitted from antenna 32 are input in the radio wave output input area 92b. The radio wave output values ​​input in radio wave output input area 92a are selected based on prior verification to ensure that information can be easily read from the RFID tag 20 via antenna 31. Similarly, the radio wave output values ​​input in radio wave output input area 92b are selected based on prior verification to ensure that information can be easily read from the RFID tag 20 via antenna 32. Furthermore, if there are RFID tags 20 that can only be read with specific output values, those output values ​​should be included in the selection.

[0063] In the session specification area 93, specify the session that determines the interval between reading information from the RFID tag 20 and reading information from the RFID tag 20 again. In the storage interval specification area 94, specify the interval for determining the mode of the temperature, which will be described later. In the alert threshold specification area 95, specify the temperature that will be the threshold for outputting an alert, which will be described later.

[0064] In addition to the settings shown in Figure 8, the reading time (e.g., 300 milliseconds) and reading stop time (e.g., 100 milliseconds) for each radio wave output value, as well as the upper limit (outlier upper limit) and lower limit (outlier lower limit) of the temperature to be controlled, can also be set. These reading time, reading stop time, and upper and lower temperature limits do not need to be set using the settings screen shown in Figure 8, but may be set in advance.

[0065] These configuration details are registered in the configuration information database 61, and the control PC 50 refers to them to execute the temperature management process described below.

[0066] After the above settings are made, the transmission level switching unit 52 of the control PC 50 sets the output value of the radio waves radiated from the antennas 31 and 32 to one of the output values ​​input to the radio wave output input area 92a and 92b (step S2).

[0067] Subsequently, for example, when the start / stop reading button (not shown) displayed on the output unit 55 of the control PC 50 is clicked or otherwise specified, the reading of information from the RFID tag 20 attached to the item 2 begins (step S3).

[0068] When reading information from the RFID tag 20 attached to item 2 begins, the processes in steps S4 to S7 and steps S8 to S12 shown in Figure 7 proceed in parallel.

[0069] When reading information from the RFID tag 20 attached to item 2 begins, first, the reading control unit 53 of the control PC 50 includes the output value set by the transmission level switching unit 52 in the command to read information from the RFID tag 20 via antennas 31 and 32, and transmits it to the reader / writer 40 via the communication unit 51.

[0070] In the reader / writer 40, when a command transmitted from the reading control unit 53 via the communication unit 51 is received via the communication unit 44, a signal for reading information from the RFID tag 20 is output from the tag data transmission processing unit 42 according to the received command, and is converted into an analog signal by the digital signal conversion unit 43.

[0071] Furthermore, in the transmission level adjustment unit 45, the output value of the radio waves radiated from antennas 31 and 32 of the signal converted to an analog signal by the digital signal conversion unit 43 is adjusted according to the output value set in the transmission level switching unit 52, transmitted from the read control unit 53 via the communication unit 51, and received via the communication unit 44. At this time, since the output value for each of antennas 31 and 32 is set in the transmission level switching unit 52, radio waves will be radiated from antennas 31 and 32 at the output value set for each of antennas 31 and 32.

[0072] Subsequently, in the RF transmission unit 46, the signal whose radio wave output value has been adjusted by the transmission level adjustment unit 45 is mounted on a carrier wave and transmitted via the combiner 41 and antennas 31 and 32, thereby executing the process of reading information from the RFID tag 20.

[0073] When the signal transmitted from the RF transmitter 46 via the shared unit 41 and antennas 31 and 32 is received by the RFID tag 20, the RFID tag 20 transmits the EPC, which is the tag ID, the detected temperature written in the Reserved area, and the correction value written in the User area to the reader / writer 40. More precisely, the RFID tag 20 first transmits the EPC as a response signal to the reader / writer 40, and then the reader / writer 40 uses the EPC to access the RFID tag 20, and transmits the detected temperature written in the Reserved area and the correction value written in the User area to the reader / writer 40.

[0074] When the EPC, temperature, and correction value transmitted from the RFID tag 20 to the reader / writer 40 are received by the RF receiver 47 via the antennas 31, 32 and the sharer 41, they are converted into digital signals by the digital signal conversion unit 43. Subsequently, the tag data reception processing unit 48 transmits the EPC, temperature, and correction value of the RFID tag 20, converted into digital signals, to the control PC 50 via the communication unit 44.

[0075] When the EPC, temperature, and correction value of the RFID tag 20 transmitted from the reader / writer 40 are received by the reading control unit 53 via the communication unit 51 of the control PC 50, the temperature management unit 54 corrects the detected temperature written in the Reserved area of ​​the RFID tag 20 by the correction value written in the User area. In this invention, the temperature corrected by the correction value written in the User area of ​​the RFID tag 20 is defined as the temperature information read from the RFID tag 20. This temperature information value is then stored in memory (not shown) in association with the EPC, the date and time of reading, the antenna ID indicating whether the antenna that read the temperature was antenna 31 or 32, and the radio wave output value at that time. Here, the reader / writer 40 recognizes whether the antenna that read the temperature information from the RFID tag 20 was antenna 31 or antenna 32. Therefore, it transmits the antenna ID of that antenna along with the temperature information from the reader / writer 40 to the control PC 50. If the EPC, reading date and time, antenna ID, and radio wave output value mentioned above have not yet been registered in the measurement information database 62 in association with each other, the temperature information first read from the RFID tag 20 will be registered in the measurement information database 62 in association with the EPC and reading date and time of the RFID tag 20 (step S8).

[0076] This series of reading processes is performed for a reading time set in step S1 for each radio wave output value (for example, 300 milliseconds) (step S4).

[0077] Subsequently, the reading process described above is paused for a reading stop time (for example, 100 milliseconds) set in step S1 for each radio wave output value (step S5).

[0078] The timing of this reading process and stopping of reading is included in the command sent from the reading control unit 53 of the control PC 50 to the reader / writer 40 for reading information from the RFID tag 20. Therefore, the reader / writer 40 performs the reading process for the reading time set in step S2 without receiving another command from the control PC 50, and then the reading process described above stops for the reading stop time set in step S2.

[0079] If the reading process is stopped in step S5 and no termination of the reading process is specified (No. in step S6), the transmission level switching unit 52 of the control PC 50 sets the output value of the radio waves radiated from antennas 31 and 32 to the other output value input to the radio wave output input area 92a and 92b (step S7), and the series of processes described above are carried out in the same manner.

[0080] Figure 9 shows an example of information stored in the memory of the control computer 50.

[0081] As shown in Figure 9, the memory of the control PC 50 stores the temperature information read from the RFID tag 20, the EPC, the date and time of reading, the antenna ID indicating whether the antenna that read the temperature information was antenna 31 or 32, and the radio wave output value at that time, all associated with each other.

[0082] The end of the reading process can be specified, for example, by the operator clicking the start / stop reading button (not shown) on the screen displayed on the output unit 55 of the control PC 50.

[0083] Furthermore, the information initially read and registered in the measurement information database 62 can also be displayed on the output unit 55 of the control PC 50 (step S9).

[0084] Meanwhile, in the temperature management unit 54 of the control PC 50, the temperature information read from the RFID tag 20 is stored in memory from the time it was last registered in the measurement information database 62 until the interval specified in the storage interval specification area 94 in step S1 (the interval for finding the mode) has elapsed. When the interval specified in the storage interval specification area 94 in step S1 has elapsed, the mode of the temperature information values ​​that have been stored in the memory of the control PC 50 up to that point is obtained for each RFID tag 20 (step S10).

[0085] Figure 10 shows an example of information about one RFID tag 20 stored in the memory of the control PC 50. In Figure 10, the reading interval has been reduced for simplicity of explanation, but in reality, temperature information is read and stored from the RFID tag 20 at more time intervals than shown. Also, in the following example, it is assumed that in step S1, 5 minutes is specified as the interval for finding the mode in the storage interval specification area 94.

[0086] In the temperature management unit 54 of the control PC 50, the most frequent temperature value within the time interval specified in the storage interval specification area 94 in step S1 is obtained for the information of one RFID tag 20 stored in memory. For example, in the case shown in Figure 10, between 11:00 and 11:05, the temperature information values ​​for the RFID tag 20 with EPC "FFFF11AA2130" are stored as 25.2°C 9 times, 25.1°C 6 times, 25.3°C 3 times, 25.0°C 2 times, and 25.4°C 1 time.

[0087] Therefore, the temperature control unit 54 registers 25.2°C, the temperature most frequently read by the EPC for the RFID tag 20 labeled "FFFF11AA2130" between 11:00 and 11:05, in the measurement information database 62. As a result, the temperature control unit 54 manages the temperature of item 2 to which the RFID tag 20 labeled "FFFF11AA2130" is attached as 25.2°C between 11:00 and 11:05.

[0088] If there are multiple modes, the lowest temperature among them may be used to manage the temperature of item 2. This is because the temperature information read from RFID tag 20 often tends to fluctuate towards the higher end. Also, depending on the environment in which RFID tag 20 is used, the read temperature information may fluctuate towards the lower end. Therefore, if there are multiple modes, depending on the environment in which RFID tag 20 is used, the lowest or highest temperature among them may be used to manage the temperature of item 2.

[0089] Furthermore, when determining the mode of temperature information, values ​​outside the predetermined range of temperature information read from the RFID tag 20 may be excluded using the outlier upper and lower limits set in step S1. For example, if 35°C is set as the outlier upper limit and 5°C as the outlier lower limit, values ​​of temperature information read from the RFID tag 20 that are less than 5°C or more than 35°C may be excluded from the calculation of the mode of temperature information. This reduces the amount of processing required to determine the mode of temperature information read within a predetermined time.

[0090] As described above, for each RFID tag 20, the most frequent temperature value within the time interval specified in the storage interval specification area 94 in step S1 is obtained and registered in the measurement information database 62 every hour. For example, as described above, if 5 minutes is specified in the storage interval specification area 94 in step S1, the most frequent temperature value is obtained every 5 minutes and registered in the measurement information database 62.

[0091] Figure 11 shows an example of information registered in the measurement information database 62.

[0092] As shown in Figure 11, for example, for an RFID tag 20 with EPC "FFFF11AA2130", the temperature based on the most frequent value within that time period will be registered in the measurement information database 62 at intervals (every 5 minutes) specified in the storage interval specification area 94. In this way, the reader / writer 40 reads temperature information multiple times within a predetermined time period, and the control PC 50 registers the temperature corresponding to the most frequently read value within that time period as a history of the temperature of item 2 in the measurement information database 62 at predetermined intervals, making it easier to manage changes in the temperature of item 2. Furthermore, if the interval for calculating the most frequent value of the temperature over a predetermined period is set to be changeable in the storage interval specification area 94, it is possible to manage temperature changes at desired intervals.

[0093] The information registered in the measurement information database 62 can also be displayed on the output unit 55 of the control PC 50 (step S11).

[0094] Subsequently, if the operator clicks the start / stop reading button (not shown) on the screen to indicate the end of the reading process (Yes in step S12), or if the end of the reading process is indicated after the reading process has stopped in step S5 (Yes in step S6), the control PC 50 outputs a command to the reader / writer 40 to terminate the reading process, the output of radio waves from antennas 31 and 32 stops, and the reading process from the RFID tag 20 ends (step S13).

[0095] On the other hand, if the end of the reading process is not specified by the read start / stop button on the screen (not shown) (No. in step S12), the process returns to step S10, and thereafter, at the time intervals specified in the save interval specification area 94 (every 5 minutes), the mode value of the temperature information within that time period is obtained, and the temperature with the obtained mode value is registered in the measurement information database 62.

[0096] After the reading process from the RFID tag 20 is completed, the information registered in the measurement information database 62 can be displayed on the output unit 55 of the control PC 50.

[0097] Figure 12 shows an example of a temperature management screen displayed on the output unit 55 of the control PC 50.

[0098] As described above, for each RFID tag 20, the most frequent temperature reading from the RFID tag 20 is determined at time intervals corresponding to the interval specified in the storage interval specification area 94 in step S1, and registered in the measurement information database 62.

[0099] Therefore, by specifying access to the measurement information database 62 or specifying that the temperature of the items 2 stored in the storage box 10 be displayed on the screen displayed on the output unit 55 of the control PC 50, for example, a temperature management screen like the one shown in Figure 12(a) can be displayed on the output unit 55 of the control PC 50.

[0100] The temperature management screen shown in Figure 12(a) displays the tag ID 71, which is the EPC of the RFID tag 20, and the read temperature 72, which is the latest temperature information value registered in the measurement information database 62 for each RFID tag 20, in correspondence with each other. In addition, alert information 73 indicating whether the latest temperature information value registered in the measurement information database 62 exceeds the threshold temperature specified in the storage interval specification area 94 in step S1 is displayed in correspondence with the tag ID 71. Note that the display area corresponding to the RFID tag 20 in which the latest temperature information value registered in the measurement information database 62 exceeds the threshold temperature specified in the storage interval specification area 94 in step S1 may be highlighted by changing the color.

[0101] Furthermore, the temperature management screen shown in Figure 12(a) may also be provided with a read start / stop button (not shown), a clear button (not shown), a CSV output button (not shown), and a setting button (not shown). The read start / stop button is used to start or stop reading information from the RFID tag 20 attached to item 2. If the read start / stop button is clicked or otherwise specified when no information is being read from the RFID tag 20 attached to item 2, reading will start. If the read start / stop button is clicked or otherwise specified when information is being read from the RFID tag 20 attached to item 2, reading will stop. The clear button is used to delete the temperature information registered in the measurement information database 62. Therefore, until the clear button is clicked or otherwise specified, the mode value obtained as described above will be registered as history for each RFID tag 20 at predetermined intervals in the measurement information database 62. Also, when the clear button is clicked or otherwise specified, the tag ID 71, read temperature 72, and alert information 73 that were displayed on the temperature management screen will no longer be displayed. The CSV output button is used to output the data of the read temperature 72 to the memory of the control PC 50, for purposes such as displaying the read temperature 72 as a graph on the output unit 55 of the control PC 50. The setting button is used to perform the settings in step S1. When the setting button is selected by clicking or other means, a screen like the one shown in Figure 8 is displayed on the output unit 55 of the control PC 50, allowing the user to perform the various settings in step S1. Note that even if information has been read from the RFID tag 20 and the temperature information of the RFID tag 20 has been registered in the measurement information database 62, the various settings in step S1 may also be performed by selecting the start / stop reading button to stop reading, and then selecting the setting button to select it.

[0102] Additionally, a history display button 74 is provided corresponding to tag ID 71. By clicking or otherwise selecting the history display button 74, it is possible to display history information 80, which is the most frequent value of the temperature information read from the RFID tag 20 with the corresponding tag ID 71, as shown in Figure 12(b).

[0103] In the history information 80, the temperature information 82 of the RFID tag 20 for which the history display button 74 was specified is displayed in association with the date and time information 81. For example, as described above, if 5 minutes is specified in the storage interval specification area 94 in step S1, the mode of the temperature information is obtained every 5 minutes, and the mode of each 5-minute interval is displayed as the temperature information 82. The date and time information 81 is the date and time of the period for which the mode was obtained. For example, for the temperature information 82 based on the mode between 11:00 and 11:05, 11:05 is associated with the date and time information 81.

[0104] Additionally, a CSV output button (not shown) may be provided in the history information 80. By clicking the CSV output button, the data of the history information 80 can be output to the memory of the control PC 50 for purposes such as displaying the history information 80 as a graph on the output unit 55 of the control PC 50.

[0105] <Verification Results> As described above, in this embodiment, the reader / writer 40 reads temperature information from the RFID tag 20 attached to the item 2 by changing the output value of the radio waves emitted from the antennas 31 and 32 within a predetermined time period. The control PC 50 manages the temperature corresponding to the temperature of the item 2 to which the RFID tag 20 is attached, which corresponds to the temperature value that was most frequently read from one RFID tag 20 within a predetermined time period by the reader / writer 40.

[0106] Therefore, we investigated the effects of adopting such an algorithm.

[0107] Figure 13 shows the results of verifying the effectiveness of managing temperature information read from RFID tags 20 by determining the mode. (a) shows the temperature fluctuation over time when no algorithm is used, and (b) shows the temperature fluctuation when the algorithm is used.

[0108] In this verification, 21 RFID tags 20 were attached to items 2 and placed inside a storage box 10. Temperature information was read four times every 10 minutes for three cases (Measurement 1-3), and the difference between the maximum and minimum values ​​was compared for each case. In the cases where an algorithm was used, the mode of the temperature information read from the RFID tags 20 over a 10-minute period was determined and used as the temperature information for each 10-minute interval.

[0109] In cases where the algorithm was not employed, as shown in Figure 13(a), the difference between the maximum and minimum values ​​was 0.4 to 0.5°C, or 1°C or more, in more than 50% of cases.

[0110] On the other hand, when the algorithm is used, as shown in Figure 13(b), the difference between the maximum and minimum values ​​is within 0 to 0.4°C in nearly 70% of cases.

[0111] Thus, using this algorithm resulted in a smaller difference between the maximum and minimum temperature values ​​across the four readings.

[0112] Figure 14 shows the maximum difference between the temperature information measured by the temperature sensor attached to item 2 and the temperature information read from the RFID tag 20 attached to item 2.

[0113] In this verification, a temperature sensor was attached to item 2 to which an RFID tag 20 was attached. The maximum difference within a predetermined time period between the temperature information measured by this temperature sensor and the temperature information read from the RFID tag 20 attached to item 2 was compared. In the cases where an algorithm was used, the mode of the temperature information read from the RFID tag 20 within the predetermined time period was calculated and used as the temperature information. In this verification, three items 2 were tested as measurements 1 to 3.

[0114] When the algorithm was not employed, the maximum difference between the temperature information measured by the temperature sensor attached to item 2 and the temperature information read from the RFID tag 20 was 0.6 to 0.9°C.

[0115] On the other hand, when the algorithm was used, the maximum difference between the temperature information measured by the temperature sensor attached to item 2 and the temperature information read from the RFID tag 20 was 0.3 to 0.4°C.

[0116] Thus, by employing this algorithm, the maximum difference between the temperature information measured by the temperature sensor attached to item 2 and the temperature information read from the RFID tag 20 was reduced.

[0117] As described above, this embodiment makes it possible to suppress variations in the detected temperature. In this case, it becomes unnecessary to process the radio waves emitted from the antenna to determine the output that will allow for accurate temperature detection, thus eliminating the need for complicated processing when managing temperature using RFID tags.

[0118] (Other embodiments) <Configuration of Reader / Writer 40> Figure 15 is a block diagram showing another configuration example of the reader / writer 40 shown in Figure 1.

[0119] The reader / writer 40 in this embodiment differs from the one shown in Figure 5 in that it has a transmission frequency adjustment unit 49, as shown in Figure 15.

[0120] The transmission frequency adjustment unit 49 switches the frequency of the radio waves from antennas 31 and 32 via the RF transmission unit 46, using the signal that has been converted to an analog signal by the digital signal conversion unit 43, by adjusting it in accordance with commands output from the control PC 50 in the communication unit 44.

[0121] The RF transmitter 46 transmits a signal whose radio wave output value has been adjusted by the transmission level adjustment unit 45, on a carrier wave at a frequency adjusted by the transmission frequency adjustment unit 49, via the combiner 41 and antennas 31 and 32.

[0122] Figure 16 is a block diagram showing another configuration example of the control PC 50 shown in Figure 1.

[0123] The control PC 50 in this embodiment differs from the one shown in Figure 6 in that it has a transmission frequency switching unit 56, as shown in Figure 16.

[0124] The transmission frequency switching unit 56 transmits a command to the reader / writer 40 via the reading control unit 53 and the communication unit 51 to switch the frequency of the radio waves radiated from the antennas 31 and 32, thereby switching the frequency of the radio waves radiated from the antennas 31 and 32 by the reader / writer 40.

[0125] When the reading control unit 53 receives a command from the transmission frequency switching unit 56 to switch the frequency of the radio waves radiated from the antennas 31 and 32 by the reader / writer 40, it includes this command in the command to read information from the RFID tag and transmits it to the reader / writer 40 via the communication unit 51.

[0126] Figure 17 is a flowchart illustrating the process for managing the temperature of items 2 stored in the storage box 10 in a configuration using the reader / writer 40 shown in Figure 15 and the control PC 50 shown in Figure 16.

[0127] In this embodiment, the process in step S22 is different from the flow shown in Figure 7, and the processes in steps S27 and S28 are added. Therefore, the processes in steps S22, S27, and S28 will be described below, and the descriptions of the other processes will be omitted.

[0128] In this embodiment, when reading information from the RFID tag 20, the transmission level switching unit 52 of the control PC 50 sets the output value of the radio waves radiated from the antennas 31 and 32 to one of the output values ​​input to the radio wave output input area 92a and 92b, and the transmission frequency switching unit 56 of the control PC 50 sets the frequency of the radio waves radiated from the antennas 31 and 32 to one of a plurality of preset frequencies (step S22). Therefore, in this embodiment, the frequencies of the radio waves radiated from the antennas 31 and 32 are set when making various settings in step S21.

[0129] Then, when reading information from the RFID tag 20 attached to item 2 begins, the reading control unit 53 of the control PC 50 includes the output value set by the transmission level switching unit 52 and the frequency set by the transmission frequency switching unit 56 in the command to read information from the RFID tag 20 via antennas 31 and 32, and transmits it to the reader / writer 40 via the communication unit 51.

[0130] In the reader / writer 40, when a command transmitted from the reading control unit 53 via the communication unit 51 is received via the communication unit 44, a signal for reading information from the RFID tag 20 is output from the tag data transmission processing unit 42 according to the received command, and is converted into an analog signal by the digital signal conversion unit 43.

[0131] Furthermore, in the transmission level adjustment unit 45, the output value of the radio waves radiated from antennas 31 and 32 of the signal converted to an analog signal by the digital signal conversion unit 43 is adjusted according to the output value set in the transmission level switching unit 52, transmitted from the read control unit 53 via the communication unit 51, and received via the communication unit 44.

[0132] Furthermore, in the transmission frequency adjustment unit 49, the frequency of the radio waves radiated from antennas 31 and 32 of the signal converted to an analog signal by the digital signal conversion unit 43 is adjusted according to the frequency set in the transmission frequency switching unit 56, transmitted from the read control unit 53 via the communication unit 51, and received via the communication unit 44.

[0133] Subsequently, in the RF transmission unit 46, the signal whose radio wave output value has been adjusted by the transmission level adjustment unit 45 is carried on a carrier wave at a frequency adjusted by the transmission frequency adjustment unit 49 and transmitted via the combiner 41 and antennas 31 and 32, thereby executing the process of reading information from the RFID tag 20.

[0134] Then, when the output of radio waves using all the output values ​​input to the radio wave output input areas 92a and 92b for a single frequency has been completed (Yes in step S27), the transmission frequency switching unit 56 of the control PC 50 switches the frequency of the radio waves radiated from antennas 31 and 32 to another set frequency (step S28), and the series of processes described above are carried out in the same manner. For example, suppose that three outputs a to c are set to read information from the RFID tag 20, and three frequencies A to C are set to read information from the RFID tag 20. In that case, first, information is read from the RFID tag 20 using the radio wave output a at frequency A, then information is read from the RFID tag 20 using the radio wave output b at frequency A, and then information is read from the RFID tag 20 using the radio wave output c at frequency A. Next, information is read from the RFID tag 20 using radio waves of frequency B with output a, then information is read from the RFID tag 20 using radio waves of frequency B with output b, then information is read from the RFID tag 20 using radio waves of frequency B with output c. Finally, information is read from the RFID tag 20 using radio waves of frequency C with output a, then information is read from the RFID tag 20 using radio waves of frequency C with output b, then information is read from the RFID tag 20 using radio waves of frequency C with output c.

[0135] In this embodiment, the reader / writer 40 reads temperature information by changing the frequency of the radio waves emitted from antennas 31 and 32 within a predetermined time period. As a result, the area in the storage box 10 in which the item 2 is stored where temperature information cannot be read from the RFID tag 20 changes by changing the frequency, thereby improving the accuracy of reading the temperature information. [Explanation of Symbols]

[0136] 2 Goods 10 Storage Boxes 11 Bottom plate part 12a~12d Side plate part 13 Lid 20 RFID tags 21 IC chips 22, 31, 32 antennas 23 Base material 24 Inlets 25 Surface sheet 27a,27b Adhesive layer 40 Reader / Writer 41 Shared device 42 Tag data transmission processing unit 43 Digital signal conversion section 44, 51 Communications Department 45 Transmission level adjustment section 46 RF Transmitter 47 RF Receiver 48 Tag data receiving processing unit 49 Transmit frequency adjustment section 50 Control PC 52 Transmission level switching section 53 Reading control unit 54 Temperature control section 55 Output section 56 Transmission frequency switching section 61 Configuration Information Database 62 Measurement Information Database 71 Tag ID 72 Reading temperature 73 Alert Information 74. History display button 80 History Information 81 Date and Time Information 82 Temperature information 91 IP address input area 92a, 92b Radio wave output input area 93 Session designation area 94 Save interval specification area 95 Alert threshold specification area

Claims

1. A temperature management system that manages the temperature of items stored in a storage container by reading temperature information detected by RFID tags attached to the items via an antenna, A reading means for reading the temperature information from the RFID tag while changing the output of the radio waves emitted from the antenna within a predetermined time period in order to read the temperature information, A temperature management system comprising: a temperature management means that manages the temperature corresponding to the most frequently read temperature information value among the temperature information values ​​read from one RFID tag within a predetermined time period by the reading means as the temperature of the article to which the RFID tag is attached.

2. In the temperature control system according to claim 1, The reading means reads the temperature information while changing the frequency of the radio waves radiated from the antenna within a predetermined time period.

3. In the temperature control system according to claim 1, The temperature management means is a temperature management system that excludes values ​​of temperature information read within a predetermined time that fall outside a predetermined range from being considered as the temperature of the item.

4. In the temperature control system according to claim 1, The reading means reads the temperature information multiple times within the predetermined time period. The temperature management means is a temperature management system that registers the temperature corresponding to the most frequently read value within the predetermined time period as a history of the temperature of the item in a database at predetermined intervals.

5. In the temperature control system according to claim 4, The aforementioned predetermined time is set to be changeable in the temperature control system.

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