Reading device, and program

Abstract

To reduce power consumption of an RFID reader under various states.SOLUTION: A reading device includes: a communication unit which transmits and receives a wireless signal to and from a wireless device, emits an electromagnetic wave into a reading range, and reads information returned from the wireless device by using energy of the electromagnetic wave; a measurement unit; a battery; a power supply unit; and a control unit which is capable of controlling the power supply unit so as to become a first state in which power consumed in the communication unit is a first power, and a second state i which the power is a second power smaller than the first power. In the reading device, when a charging control unit detects that the battery is in a charging state, the control unit controls, on the basis of the measurement result of the measurement unit, the power supply unit so that a period of time in the first state is shorter than a period of time in the second state.SELECTED DRAWING: Figure 7

Description

[Technical field]

[0001] The present invention relates to a reading device and a program. [Background technology]

[0002] RFID (Radio Frequency Identification) is a technology that enables information embedded in small devices, also known as tags, to be read by an external reader via short-range wireless communication. Passive RFID tags transmit information using the energy of electromagnetic waves emitted from a reader, and are widely used in a variety of situations, such as for managing and visualizing the location of items, because they do not require batteries and are therefore inexpensive to manufacture and can function semi-permanently.

[0003] Patent Document 1 describes a method in which a reader is carried, and the reader detects RFID tags at the destination and reads information. Patent Document 1 also describes a method in which the reader detects the position where the RFID tag is read, associates the position information with the ID information of the RFID tag and stores it, and executes a process of reading information from an RFID tag at a position where information has not been read before. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2007-266936 A Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention aims to further improve the technology for reducing the power consumption of a reader. [Means for solving the problem]

[0006] A reader device according to one embodiment of the present invention is a reading device comprising a communication unit that transmits and receives wireless signals with a wireless device, the communication unit emitting electromagnetic waves within a reading range and reading information returned from the wireless device using the energy of the electromagnetic waves, a measurement unit that measures at least one of the posture or amount of movement of the reading device, a battery that can be charged with power input from an external source, a power supply unit that controls the power supplied from the battery to the communication unit, a control unit that can control the power supply unit to a first state in which the power consumed by the communication unit is a first power, and a second state in which the power consumed by the communication unit is a second power less than the first power, and a charging control unit configured to detect whether the battery is charging, wherein when the charging control unit detects that the battery is charging, the control unit controls the power supply unit so that the period of the first state is shorter than the period of the second state based on the measurement result by the measurement unit. Effect of the Invention

[0007] According to the present invention, it is possible to reduce the power consumption of a reading device in various situations. [Brief description of the drawings]

[0008] [Figure 1] FIG. 2 is a diagram illustrating an example of the configuration of an RFID reader. [Diagram 2] FIG. 1 is a diagram illustrating an example of a moving object carrying an RFID reader. [Diagram 3] FIG. 2 is an explanatory diagram of the appearance of an RFID reader. [Figure 4] FIG. 1 is a diagram illustrating a position detection system of an RFID reader. [Diagram 5] FIG. 11 is a diagram showing an example of a flow of processing executed in an RFID reader. [Figure 6] 1 is a diagram illustrating an example of a connection between an RFID reader and an external power supply. [Figure 7] FIG. 11 is a diagram showing an example of a flow of processing executed in an RFID reader. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, the embodiments will be described in detail with reference to the attached drawings. Note that the following embodiments do not limit the invention according to the claims. Although the embodiments describe a number of features, not all of these features are essential to the invention, and the features may be combined in any manner. Furthermore, in the attached drawings, the same reference numbers are used for the same or similar configurations, and duplicated descriptions are omitted.

[0010] In this embodiment, a system in which an RFID reader, which is a portable reading device, detects RFID tags that are placed over a wide area will be described. This RFID reader suppresses power consumption by reducing power consumption according to the situation. In particular, in this embodiment, the RFID reader sets the length of the period during which it should operate at low power consumption according to changes in its own position and attitude and whether it is supplied with power from an external source. For example, when the amount of change in the situation of the RFID reader is small, the operation period at low power consumption is extended so as not to consume power unnecessarily, and when the amount of change in the situation of the RFID reader is large, the operation period at low power consumption is shortened. Also, when power is supplied from an external source and the battery, which is the operating power source within the RFID reader, is in a charged state, there is little change in position and attitude, and the RFID reader operates at low power consumption so as not to consume power unnecessarily even when it is stationary. The following will focus on the configuration and operation of such an RFID reader.

[0011] (Device configuration) FIG. 1 shows a configuration example of an RFID reader 100. The RFID reader 100 is configured to be carried by a moving object such as a person, an animal, or a machine, and to detect an RFID tag 150 present in a wide range as the moving object moves. The RFID tag 150 operates using radio waves emitted from an antenna 115 of the RFID reader 100 as a power supply source. That is, the RFID reader 100 supplies UHF electromagnetic waves to the RFID tag 150, and the electromagnetic waves operate an IC chip (not shown) inside the RFID tag 150 to read out ID information stored in a memory unit of the RFID tag 150. The RFID reader 100 can detect the RFID tag 150 by approaching the RFID tag 150 sufficiently (within a reading range of several meters) and perform such wireless communication with the RFID tag 150. In one example, the RFID reader 100 can be carried by being worn by a person (animal) as shown in FIG. 2(A). The RFID reader 100 may also be transported by being attached to a mobile machine such as a drone 201 or an automated guided vehicle 202 as shown in FIGS. 2(B) and 2(C).

[0012] The RFID reader 100 includes, for example, a calculation unit 101 which is a control unit, a storage unit 102, an external communication unit 103, a movement tilt amount detection sensor 104, a power supply unit 105, a battery 106, and a charging control unit 107 for the battery 106. Furthermore, the RFID reader 100 is configured so that an external power source 200 can be connected to the charging control unit 107 to charge the battery 106.

[0013] The calculation unit 101 controls the overall operation of the RFID reader 100. For example, the calculation unit 101 executes a computer program stored in the storage unit 102, thereby causing the RFID reader 100 to perform each operation described below and an operation as a general RFID reader. The calculation unit 101 includes one or more processors and processing circuits, such as a central processing unit (CPU), a microprocessor, an application specific integrated circuit (ASIC), and a field programmable gate array (FPGA). The storage unit 102 stores programs and data for executing these operations. The storage unit 102 includes at least one memory, such as a read only memory (ROM) or a random access memory (RAM) that temporarily stores information, or another storage medium, such as a hard disk. The calculation unit 101 and the storage unit 102 may be integrated together, and for example, a one-chip microcomputer may be used.

[0014] The external communication unit 103 communicates with an external device other than the RFID reader 100 by a communication method other than that of RFID, for example. For example, the external communication unit 103 can be configured to be capable of communicating using a cellular communication system or a wireless LAN communication system.

[0015] The measurement section includes a movement / tilt amount detection sensor 104 that detects at least one of the movement amount and tilt amount of the RFID reader 100, and is configured to include, for example, a three-axis acceleration sensor, a gyro sensor, or a geomagnetic sensor.

[0016] The power supply unit 105 is connected to a battery 106 such as a rechargeable and reusable secondary battery, and supplies power provided by the battery 106 to each functional unit of the RFID reader 100. The power supply unit 105 is configured by a circuit including, for example, a DC-DC converter, and is configured to be capable of executing power supply control based on the control of the calculation unit 101, for example.

[0017] The charging control unit 107 is configured to charge the battery 106 by supplying power to the battery 106 and the calculation unit 101 from the battery and the external power supply 200, and the calculation unit 101 detects the charging state of the battery 106.

[0018] The RFID communication unit 120 is controlled by the calculation unit 101 and performs detection processing of the RFID tag 150. The RFID communication unit 120 has, for example, an RF control unit 110, a power amplifier 111, a low-pass filter 112, a first coupler 113, a second coupler 114, an antenna 115, and an RF power detection unit 116. The RF control unit 110 outputs a UHF band RF (radio frequency) waveform from a Tx terminal. The RF waveform is amplified by the power amplifier 111, and then unnecessary frequency band components are cut from the amplified waveform by the low-pass filter 112. The waveform from which unnecessary frequency band components have been cut is input to the first coupler 113. Note that the power of the RF waveform is variable and can be set by the calculation unit 101. The RF power detection unit 116 monitors the first coupler 113 and detects the power of the RF waveform at the first coupler 113. The RF power detection unit 116 inputs the power detection result to the calculation unit 101 as an RF_Detect signal, and the calculation unit 101 can detect that the power of the RF waveform has been input to the first coupler 113 by this RF_Detect signal. The second coupler 114 outputs an RF waveform to the antenna 115. The second coupler 114 also receives an RF signal received from the outside by the antenna 115, and inputs the input signal to the RF control unit 110. For example, the RF control unit 110 can acquire ID information from the RFID tag 150 via the antenna 115 and the second coupler 114. The antenna 115 outputs electromagnetic waves in the UHF band and supplies power by irradiating the electromagnetic waves to the RFID tag 150. The antenna 115 then transmits and receives signals by electromagnetic waves between the RFID tag 150 that is the target of the electromagnetic waves. Incidentally, irradiating the RFID tag 150 with electromagnetic waves may be referred to as radio wave irradiation hereinafter.

[0019] In this embodiment, the RFID reader 100 detects the relative position information between the RFID tag and the RFID tag by the movement tilt amount detection sensor 104 while detecting the ID information of the RFID tag, as described later in relation to FIG. 4. Then, the RFID reader 100 uses the ID information of the RFID tags in association with the relative position information between the RFID tags. For this purpose, the calculation unit 101 stores the ID information of the RFID tag 150 detected by the RF control unit 110 and the movement amount information detected by the movement tilt amount detection sensor 104 in the storage unit 102, and performs necessary data processing. Thereafter, the calculation unit 101 communicates with the information terminal 401, which will be described later in relation to FIG. 4, via the external communication unit 103. In one example, the RFID reader 100 can be configured to communicate with the information terminal 401 via the external communication unit 103 after collecting a predetermined amount of each of the above-mentioned information in the storage unit 102. With such a configuration, it is possible to suppress the frequency of communication with the information terminal 401 and reduce the power consumption of the RFID reader 100. Furthermore, with this configuration, when the RFID reader 100 cannot communicate with the information terminal 401, the information can be temporarily stored in the storage unit .

[0020] In one example, the calculation unit 101 reads the RFID tag 150, performs calculation control described later in relation to Fig. 5, and controls switching of the RFID reader 100 to a power saving operation described later in relation to Fig. 6. The calculation unit 101 has a timer 121 that sets an operation period of the RFID reader 100, and the timer 121 can count multiple times in parallel, such as a time timer and a timer for determining the passage of a predetermined period. The calculation unit 101 also stores in the storage unit 102 the setting value of the timer 121 that sets the operation period of the RFID reader 100, and the position information and tilt (posture state) information of the RFID reader 100 as measurement results.

[0021] 3(A) and 3(B) are diagrams for explaining an example of the appearance of the RFID reader 100. FIG. 3(A) shows the front appearance of the RFID reader 100. Also, FIG. 3(B) shows the rear appearance of the RFID reader 100. In FIG. 3(A), the position of the antenna 115 of the RFID reader 100 is indicated by a dashed line. The movement and tilt amount of the RFID reader 100 is indicated by the movement amount in the XYZ axis directions and the rotation angle in the α-β-γ directions, and the movement and tilt amount detection sensor 104 detects these amounts. Here, α is the rotation angle around the Z axis, β is the rotation angle around the Y axis, and γ is the rotation angle around the X axis.

[0022] In one example, the movement direction of the RFID reader 100 is defined as a movement to the right when it moves in the direction of the X-axis arrow when viewed from the viewpoint of FIG. 3(A), and as a movement to the left when it moves in the opposite direction to the X-axis arrow. In addition, the movement in the direction of the Y-axis arrow in FIG. 3(A) is defined as a movement to the front, and as a movement to the opposite direction to the Y-axis arrow, as a movement to the rear. In addition, the movement in the direction of the Z-axis arrow in FIG. 3(A) is defined as a movement to the upward direction, and as a movement to the opposite direction to the Z-axis arrow, as a movement to the downward direction. In one example, the antenna 115 of the RFID reader 100 may have a characteristic of irradiating a strong electric wave in the forward direction of FIG. 3(A). In this case, the forward direction is called the direction of electric wave irradiation.

[0023] In one example, the inclination state of the RFID reader 100 is defined as a backward-facing state when the rotation angle α reaches 180° in the direction of the arrow (or the direction opposite to the arrow) when viewed from the viewpoint of FIG. 3(A). As an example, FIG. 3(B) shows a state in which the rotation angle α reaches 180° and the RFID reader 100 faces backward. In addition, a state in which the rotation angle β from the state of FIG. 3(A) has a value in the range up to 180° in the direction of the arrow is defined as a left-facing state, and a state in which the rotation angle β has a value in the range up to 180° in the opposite direction to the arrow is defined as a right-facing state. In addition, a state in which the rotation angle γ from the state of FIG. 3(A) has a value in the direction of the arrow from 90° is defined as an upward-facing state, and a state in which the rotation angle γ has a value in the opposite direction to the arrow is defined as a downward-facing state.

[0024] Next, the article position detection system according to the present embodiment will be described with reference to FIG. 4. In this system, as an example, the RFID tag 150 is classified into position RFID tags 430a, 430b, 430c, etc. that are used to detect the reference position, and article RFID tags 440a, 440b, etc. that are attached to the managed article. The RFID reader 100 transmits to the information terminal 401 information that associates ID information of the detected article RFID tag 440 and position RFID tag 430 with information on the relative positions (x, y, z) of the article RFID tag 440 and the position RFID tag 430. The RFID reader 100 may also transmit information on the time when the RFID tag 150 was detected to the information terminal 401. For example, the information terminal 401 may measure the time when the information was acquired from the RFID reader 100 using an internal clock, and hold the measured time. The RFID reader 100 transmits information to the information terminal 401 using, for example, the external communication unit 103 .

[0025] The information terminal 401 includes a database 411, a database 412, and a display unit 413. The information terminal 401 may be, for example, a smartphone or a PC. The database 411 holds data in which the ID information of the position RFID 430 is associated with a position name, and data in which the ID information of the item RFID 440 is associated with an item name. Here, the ID information of the RFID tag may be a complex character string, which is difficult for a user to recognize. For this reason, in the information terminal 401, for example, when displaying information on the display unit 413, the ID information is converted into a position and an item name based on the database 411, and these names are displayed. Note that the ID information of the RFID may be displayed directly on the display unit 413 without using the database 411. The database 412 stores data in which the ID information of the position RFID tag 430 and the item RFID tag 440, the relative positions of the position RFID tag 430 and the item RFID tag 440, and the time when the item RFID tag 440 is detected are associated with each other. As described above, the information terminal 401 receives these pieces of information from the RFID reader 100 and stores them in the database 412. The display unit 413 displays the location information of the item identified by referring to the database 412 based on a user instruction received via an interface (not shown) of the information terminal 401.

[0026] The configuration of the position detection system is an example, and for example, the RFID reader 100 may be included in the information terminal 401. In this case, the information terminal 401 can collect the above-mentioned information via the built-in RFID reader 100 and execute various processes such as presenting information notifying the user of the position of an article. Also, a system using an article RFID tag and a position RFID tag is an example, and for example, the RFID reader 100 may be a device capable of identifying the position of its own device, and notify the information terminal 401 of the information of the detected RFID tag 150 together with the position of its own device.

[0027] (Processing flow) Next, an example of the flow of processing executed by the RFID reader 100 will be described. Fig. 5 shows an example of the flow of processing in which the RFID reader 100 switches between a period in which the RFID reader 100 executes a detection process for the RFID tag 150 and a period in which the RFID reader 100 reduces power without executing such a detection process. This processing can be realized, for example, by the calculation unit 101 of the RFID reader 100 executing a program stored in the storage unit 102 in response to the power supply of the RFID reader 100 being turned on. Note that, although a case in which the calculation unit 101 executes processing using the timer 121 will be described below, this is merely an example, and the following processing may be executed by one or more arbitrary functional units included in the RFID reader 100.

[0028] In this process, the calculation unit 101 first sets the timer 121 to measure a period T1 during which the RFID tag 150 is detected (in a normal state in which a sufficiently large amount of power is consumed), and starts measuring the period T1 (S501).

[0029] The calculation unit 101 reads out a timer setting value for the period T1 from the storage unit 102, for example, and sets the timer 121. The timer 121, for example, constantly counts inside the calculation unit 101, and can execute timekeeping from the time when it is set until a predetermined period (here, the period T1) expires. Note that this is just an example, and the timer 121 may start timing in response to the period T1 being set, and may be any type of timer that can determine whether the set period has expired. Note that, for example, immediately after the power supply of the RFID reader 100 is turned on, the calculation unit 101 may set the timer 121 to an initial value of the period T1 stored in a ROM or the like (not shown) provided inside the calculation unit 101. Next, the calculation unit 101 performs settings for the RFID reader 100 to detect the RFID tag 150, and executes detection of the RFID tag 150 based on the settings (S502). Then, the calculation unit 101 determines whether the period T1 for detecting the RFID tag 150, for which timing was started in S501, has elapsed by checking the timer 121 (S503). While the period T1 has not elapsed (NO in S503), the calculation unit 101 repeatedly executes the detection process for the RFID tag 150 (S502), and when it is determined that the period T1 has elapsed (YES in S503), the calculation unit 101 advances the process to S504.

[0030] In S504, the calculation unit 101 sets the timer 121 to measure a period T2 during which power consumption is reduced (hereinafter referred to as a "reduced power period"), and starts measuring the period T2. The calculation unit 101 reads out, for example, a timer setting value for the period T2 from the storage unit 102, and sets the timer 121. Next, the calculation unit 101 sets a state in which power is reduced (hereinafter referred to as a "reduced power state"), and executes an operation in the reduced power state based on the setting (S505). That is, in the reduced power state, the calculation unit 101 controls the power supply unit 105 to reduce consumption of power stored in the battery 106. The reduced power state is, for example, a state in which the RF control unit 110 reduces the amplitude of the RF waveform from the Tx terminal or reduces the amplification factor of the power amplifier 111 based on the control of the calculation unit 101, thereby reducing the intensity of the electromagnetic wave output from the RFID reader 100. Note that the RFID reader 100 may stop outputting radio waves in the reduced power state. In addition to this, for example, in the reduced power state, the operating clocks of the calculation unit 101 and the storage unit 102 may be slowed down or stopped, and these functional units may be put into a sleep mode, thereby further reducing power consumption. Furthermore, the power consumption can be further reduced by stopping the operation of the external communication unit 103 and the RF power detection unit 116. The normal state in which the period T1 is set is the first state. The reduced power state in which the period T2 is set is the second state. If the first power is consumed by the RFID communication unit 120 in the first state, the second power, which is less than the first power, is consumed by the RFID communication unit 120 in the second state. Here, the second power includes zero. That is, in the reduced power state, there are cases where at least the RFID communication unit 120 does not supply power.

[0031] The calculation unit 101 determines whether the period T2, whose timing was started in S504, has elapsed by checking the timer 121 (S506). The calculation unit 101 maintains the reduced power state (S505) while the period T2 has not elapsed (NO in S506), and ends the processing when it is determined that the period T2 has elapsed (YES in S506). The calculation unit 101 may repeatedly execute the processing of Fig. 5. That is, the calculation unit 101 may return the processing to S501 after the period T2 has elapsed, set the periods T1 and T2 again, and operate while alternately switching between a state in which the RFID tag 150 is detected and a reduced power state.

[0032] In this embodiment, the RFID reader 100 controls the time lengths of the periods T1 and T2 according to the amount of movement of the RFID reader 100. For example, when it is assumed that there is no change (or a sufficiently small change) in the position of the RFID reader 100 and there is no change in the detected RFID tag 150, the RFID reader 100 relatively lengthens the period T2 and relatively shortens the period T1 to sufficiently suppress power consumption. On the other hand, when there is a change in the position of the RFID reader 100 and there is a change in the detected RFID tag 150, the RFID reader 100 relatively lengthens the period T1 and relatively shortens the period T2 to prevent the surrounding RFID tag 150 from being overlooked. This allows the RFID reader 100 to reliably detect the RFID tag 150 while reducing power consumption.

[0033] The calculation unit 101 determines and sets the time lengths of the periods T1 and T2 by the procedure described below. The calculation unit 101 may update the periods T1 and T2 in response to detection of a change in the situation, such as an increase or decrease in the amount of movement of the device itself. This update may be performed only during the period T1, may be performed only during the period T2, or may be performed regardless of the period.

[0034] When the update is performed only during the period T1, the calculation unit 101 may newly set the length of the period T1 while the timer 121 is measuring the period T1 according to the length of the period T1 set in advance. In this case, the timer 121 may measure the period T1 with the updated length. In one example, when the calculation unit 101 newly sets the length t10 of the period T1, if the time t11 has elapsed since the start of measuring the period T1, the RFID reader 100 may transition to the period T2 after the period of length t10-t11 has elapsed. Also, when t11 is greater than t10, that is, when the length of the period T1 has elapsed at the time the length of the period T1 is updated, the RFID reader 100 may immediately transition to the period T2. Similarly, when the update is performed only during the period T2, the calculation unit 101 may newly set the length of the period T2 while the timer 121 is measuring the period T2 according to the length of the period T2 set in advance. In this case, the timer 121 may measure the period T2 with the updated length. In one example, when the calculation unit 101 newly sets the length t20 of the period T2, if a time t21 has elapsed since the start of timing the period T2, the RFID reader 100 may transition to the period T1 after the period of length t20-t21 has elapsed. Also, if t21 is greater than t20, that is, if the period of length T1 has elapsed when the length of the period T1 is updated, the RFID reader 100 may immediately transition to the period T2.

[0035] In another example, the length of the updated period T1 determined by the calculation unit 101 in the period T1 may not be applied to the period T1 at that time, but may be applied from the next period T1. Similarly, the length of the updated period T2 determined by the calculation unit 101 in the period T2 may not be applied to the period T2 at that time, but may be applied from the next period T2. Note that the setting for the other period is changed during the period in which the calculation unit 101 determines the lengths of the periods T1 and T2. As a result, the other period is measured with the updated length.

[0036] When an update is performed regardless of the period, the above-mentioned processing when an update is performed during period T1 and the above-mentioned processing when an update is performed during period T2 can be selectively executed depending on the timing of the update.

[0037] When the calculation unit 101 is shifted to a sleep mode in period T2 to stop the calculation process, it is assumed that the calculation unit 101 may not be able to process the detection result of the amount of movement, etc. (to determine the period T1 or period T2) immediately after the result is obtained. In this case, for example, information on the detected amount of movement, etc. may be stored in a memory (not shown) provided in the movement / tilt amount detection sensor 104, etc., and the calculation unit 101 may set the time lengths of the periods T1 and T2 in period T1 based on this information.

[0038] (External power connection) FIG. 6A shows a configuration in which the RFID reader 100 is connected to an external power source 200 and the battery 106 in the RFID reader 100 is charged via a charging control unit 107.

[0039] The RFID reader 100 is shown in a state where it is being charged, without moving or changing its posture, and is stationary on a member 300 such as a table or a storage location for the RFID reader 100, with the positive direction of the Y axis facing upward.

[0040] On the other hand, FIG. 6(B) shows a state in which the RFID reader 100 is standing still on the member 300, and shows a state in which the battery 106 in the RFID reader 100 is not being charged.

[0041] A connection point for connecting to an external power source 200 (not shown) is provided on the bottom surface of the RFID reader 100, which is in the opposite direction of the Z axis of the RFID reader 100, and a state in which connection to the external power source 200 is not possible is shown.

[0042] (Setting of periods T1 and T2 due to changes in external power supply connection status) A first example of a procedure flow for setting the periods T1 and T2 is shown in Fig. 7. Fig. 7 shows an example of a procedure for the RFID reader 100 to set the lengths of the periods T1 and T2 according to the amount of change in position (i.e., the amount of movement) and the amount of change in inclination (the amount of change in attitude).

[0043] In the procedure of FIG. 7, the calculation unit 101 first sets the timer 121 to operate as a time timer for timing to specify the timing of position measurement, and starts timing (S701). When the time timer reaches time t1, the calculation unit 101 causes the movement tilt amount detection sensor 104 to detect the position and tilt information of the RFID reader 100, and acquires the detection result (S702). The calculation unit 101 stores the position information and tilt information in the storage unit 102. After that, when a predetermined time has elapsed from time t1 by the timer 121 and the time timer reaches time t2 (YES in S703), the calculation unit 101 causes the movement tilt amount detection sensor 104 to detect the position and tilt information of the RFID reader 100 again, and acquires the detection result (S702). The calculation unit 101 stores the position information and tilt information in the storage unit 102. The position of the RFID reader 100 at the time of detection can be expressed by position information of the relative position with respect to the position RFID tag 430 detected at time t1, for example. For example, the position information at time t1 can be expressed as relative position coordinates (x1, y1, z1), and the position information at time t2 can be expressed as relative position coordinates (x2, y2, z2). These position coordinates may be expressed in a format other than the relative position with respect to the position RFID tag 430. The calculation unit 101 causes the movement tilt amount detection sensor 104 to detect the tilt amount of the RFID reader 100 at time t1 and time t2, and stores the detection result as tilt information in the storage unit 102. The tilt information at time t1 is expressed as (α1, β1, γ1), and the tilt information at time t2 is expressed as (α2, β2, γ2).

[0044] Then, the calculation unit 101 reads out the position information at time t1 and time t2 from the storage unit 102, and judges whether the amount of change in the position of the RFID reader 100 between time t1 and time t2 is less than a predetermined amount (S705).

[0045]

number

[0046] The amount of change in the position of the RFID reader 100 from time t1 to time t2 may be calculated as the absolute value of the difference for each coordinate axis as follows:

[0047]

number

[0048] The calculation unit 101 also reads out the tilt information at time t1 and time t2 from the storage unit 102, and determines whether the amount of change in tilt of the RFID reader 100 from time t1 to time t2 is less than a predetermined amount.

[0049]

number

[0050] The amount of change in tilt of the RFID reader 100 from time t1 to time t2 may be calculated as the absolute value of the difference for each rotation axis as follows:

[0051]

number

[0052] When the amount of change in position or the amount of change in inclination is less than a predetermined amount (YES in S705), the calculation unit 101 determines that the movement speed or the change in attitude of the RFID reader 100 is slow. In this case, the calculation unit 101 determines via the charging control unit 107 whether the RFID reader 100 is supplied with power from the outside by the external power source 200 or the like. When the calculation unit 101 determines that power is being supplied from the outside (YES in S706), the movement speed or the change in attitude of the RFID reader 100 is also slow. In this case, even if the period T2 is lengthened, the calculation unit 101 sets the timer setting value of the period T1 for detecting the RFID tag 150 to a short period and stores the setting value in the storage unit 102 (S707), since the RFID tag 150 is unlikely to be missed even if the period T2 is lengthened. In addition, the calculation unit 101 sets the timer setting value of the period T2 for reducing the power of the RFID reader 100 to a long period and stores the setting value in the storage unit 102 (S708).

[0053] On the other hand, when the amount of change in position or inclination is equal to or greater than the predetermined amount (NO in S705), the calculation unit 101 determines that the movement speed or change in posture of the RFID reader 100 is fast. In this case, in order to avoid missing detection of the RFID tag 150 present around the RFID reader 100, the calculation unit 101 sets the timer setting value of the period T1 during which the RFID tag 150 is detected to a long period, and stores the setting value in the storage unit 102 (S709). In addition, the calculation unit 101 sets the timer setting value of the period T2 during which the power of the RFID reader 100 is reduced to a short period, and stores the setting value in the storage unit 102 (S710).

[0054] 6(B), when it is determined that power is not being supplied from the outside (NO in S706), the calculation unit 101 sets the timer setting value of the period T1 during which the RFID tag 150 is detected to a long period, and stores the setting value in the storage unit 102 (S709). Furthermore, the calculation unit 101 sets the timer setting value of the period T2 during which the power of the RFID reader 100 is reduced to a short period, and stores the setting value in the storage unit 102 (S710).

[0055] In addition, as shown in Figure 6 (B), while the RFID reader 100 is in a stationary state, depending on the posture of the RFID reader 100 that can be detected by the movement tilt detection sensor 104, the calculation unit 101 may set the timer setting value for period T1 to a longer period than when the RFID reader 100 is stationary, and set the timer setting value for period T2, in which the power of the RFID reader 100 is reduced, to a shorter period than when the RFID reader 100 is stationary, thereby controlling to avoid missing detection of RFID tags 150 present around the RFID reader 100.

[0056] 7, it is assumed that the RFID reader 100 is almost stopped when the amount of change in position (amount of movement) or amount of change in inclination (amount of change in attitude) is small. Furthermore, when the RFID reader 100 is supplied with power from the outside by the external power source 200 or the like, the battery 106 arranged inside the RFID reader 100 is also in a state of charging, and for example, the intensity of the output electromagnetic waves is reduced. This allows the RFID reader 100 to reduce the frequency of reading the RFID tag 150, and to sufficiently suppress power consumption.

[0057] On the other hand, if the amount of change in position or inclination is large even when power is being supplied from an external source such as the external power source 200, it is assumed that the RFID reader 100 is moving or changing its posture quickly. Therefore, in order to prevent RFID tags from being overlooked, the RFID reader 100 increases the intensity of the electromagnetic waves it outputs, for example. This enables the RFID reader 100 to read the RFID tags 150 more frequently and detect the RFID tags 150 present in the vicinity with high accuracy.

[0058] According to the control procedure in Fig. 7, even if the position of the RFID tag 150 detected in the past has changed, the power consumption can be reduced according to the state of the RFID reader 100 regardless of the change. Furthermore, according to the control procedure in Fig. 7, the position information of the RFID tag 150 detected in the past is not required, so there is no need to communicate with the information terminal 401 to inquire about the past position information of the RFID tag 150. Therefore, the RFID reader 100 can reduce the power consumption required for communication.

[0059] The calculation unit 101 repeatedly executes the process of Fig. 7. This allows the RFID reader 100 to properly detect the RFID tags 150 without omission depending on the state of the RFID reader 100, and can sufficiently reduce the power consumption of the RFID reader 100. Note that in each of the above-mentioned processes, the calculation unit 101 may use the position information and tilt information detected at time t2 in the previous process as the position information and tilt information at time t1 in the next process. This makes it possible to omit the information collection process at t1, and to continuously execute each process.

[0060] In the above processing example, the set values ​​of the period T1 and the period T2 are set in two stages, but control may be performed so that the ratio of the period length of the period T1 to the period T2 increases in proportion to the amount of movement, the amount of change in the inclination, etc. For example, the set values ​​may be set in a plurality of stages, for example, three or more stages, such that the larger the amount of movement, the amount of change in the inclination, etc., the longer the period T1 and the shorter the period T2, and the smaller the amount of movement, the amount of change in the inclination, etc., the shorter the period T1 and the longer the period T2. Also, control may be performed so that the periods T1 and T2 are calculated each time using the magnitude of the amount of movement, the amount of change in the inclination, etc. as an argument, and the lengths of the periods T1 and T2 can be adjusted steplessly.

[0061] In the above processing example, the intensity of the electromagnetic waves output during each of the periods T1 and T2 has been described as a fixed value, but the intensity of the electromagnetic waves output may be controlled to be weakened in inverse proportion to the amount of change in the movement amount or the tilt. That is, a set value may be set across multiple steps, for example three or more steps, such that the intensity of the electromagnetic waves output is increased as the amount of change in the movement amount or the tilt increases, and decreased as the amount of change in the movement amount or the tilt decreases. The intensity of the electromagnetic waves may also be controlled to be steplessly adjustable.

[0062] As described above, by performing the above-mentioned processes, it is possible to reliably detect the RFID tag 150 while suppressing power consumption in response to changes in the state of the RFID reader 100.

[0063] In the above embodiment, an example in which an RFID tag is used as a wireless device is described, but the present invention is not limited to this. For example, the above process can be applied to any reader device that radiates minute power and receives responses from surrounding communication objects.

[0064] The present invention can also be realized by a process in which a program for implementing one or more of the functions of the above-described embodiments is supplied to a system or device via a network or a storage medium, and one or more processors in a computer of the system or device read and execute the program. The present invention can also be realized by a circuit (e.g., ASIC) that implements one or more of the functions.

[0065] The invention is not limited to the above-described embodiments, and various modifications and variations are possible without departing from the spirit and scope of the invention. Accordingly, the following claims are appended to apprise the public of the scope of the invention. [Explanation of symbols]

[0066] 100 RFID Readers 101 Control section 102 Storage section 105 Power supply section 106 Battery 107 Charging control unit 120 RFID communication unit 121 Timer 200 External power supply

Claims

1. A reading device, a communication unit for transmitting and receiving signals to and from a wireless device, the communication unit emitting electromagnetic waves within a reading range and reading information transmitted from the wireless device by utilizing the energy of the electromagnetic waves; A measurement unit that measures at least one of the posture or the amount of movement of the reading device; A battery that can be charged by power input from an external source; a power supply unit that controls power supplied from the battery to the communication unit; a control unit capable of controlling the power supply unit to a first state in which the power consumed by the communication unit is a first power and a second state in which the power consumed by the communication unit is a second power less than the first power; a charging control unit configured to detect whether the battery is being charged; Equipped with A reading device characterized in that, when the charging control unit detects that the battery is being charged, the control unit controls the power supply unit based on the measurement results by the measurement unit so that the period of the first state is shorter than the period of the second state.

2. 2. The reading device according to claim 1, wherein the control unit controls the power supply unit so as to alternately repeat the first state and the second state.

3. The reading device described in claim 2, characterized in that when the charging control unit detects that the battery is being charged and when the measurement result of the movement amount by the measurement unit is less than a predetermined amount, the control unit controls the power supply unit so that the period of the first state is shorter than the period of the second state, and when the measurement result of the movement amount by the measurement unit is equal to or greater than a predetermined amount, the control unit controls the power supply unit so that the period of the first state is longer than the period of the second state.

4. The reading device according to claim 3, characterized in that, when the charging control unit detects that the battery is not being charged, the control unit controls the power supply unit so that the period of the first state is longer than the period of the second state.

5. The reading device according to claim 1 , wherein the control unit does not cause the communication unit to emit electromagnetic waves in the second state.

6. 2. The reading device according to claim 1, further comprising an external communication unit that transmits information about the wireless device detected by the communication unit to a device other than the reading device.

7. 2. The reader of claim 1, wherein the wireless device is an RFID tag.

8. 2. The reading device according to claim 1, wherein the measurement unit measures both the attitude and the amount of movement of the reading device.

9. A program for causing a computer to function as the reading device according to any one of claims 1 to 8.

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