JP2017054175A - Mobile terminal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mobile terminal that can save power for radio communication depending on processing capability of information processing means.SOLUTION: A mobile terminal detects the readout number N of RFID tags 60 processed per certain time by using a control unit 21 (S105), and adjusts radio wave strength of an electromagnetic wave transmitted by a non-contact communication unit 30 so as to be lower (S109) if it determines that the detected readout number N is equal to or more than a limit readout number N1 stored in a memory 22 (Yes at S107).SELECTED DRAWING: Figure 4

Description

  The present invention relates to a portable terminal that reads information stored in an RFID tag by wirelessly communicating with the RFID tag.

  Conventionally, for example, an RFID reader disclosed in Patent Document 1 below is known as a technique related to a portable terminal that reads information stored in an RFID tag by wirelessly communicating with the RFID tag. In this RFID reader, a first electromagnetic wave for detecting an RFID tag and a second electromagnetic wave for reading data from the RFID tag are prepared, and transmitted from the RFID tag during repeated transmission of the first electromagnetic wave. When a second electromagnetic wave is received, a second electromagnetic wave is transmitted. Then, during the transmission of the second electromagnetic wave, the power consumption of the RFID reader is reduced by controlling the transmission output of the second electromagnetic wave according to the transmission / reception sensitivity of the electromagnetic wave between the RFID reader and the RFID tag. Yes.

JP 2011-081745 A

  Incidentally, in recent years, there has been a demand for further performance such as reducing the power consumption while improving the reading speed for wireless communication. If the emphasis is simply on improving the reading speed in order to satisfy this requirement, the number of RFID tags read increases, but power is greatly consumed to process the increased RFID tags. Also, if too much importance is placed on reducing power consumption, the performance capability of the mobile terminal will be reduced, making it difficult to improve the reading speed. This problem is particularly noticeable in portable terminals that read a large number of dense RFID tags, such as inventory work using RFID tags.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a portable terminal capable of saving power related to wireless communication according to the processing capability of the information processing means. is there.

In order to achieve the above object, the invention according to claim 1 is a portable terminal (10) that reads information stored in an RFID tag by wirelessly communicating with the RFID tag (60). Electromagnetic wave transmitting means (30) for transmitting electromagnetic waves to the RFID tag, electromagnetic wave receiving means (30) for receiving electromagnetic waves transmitted from the RFID tag in response to transmission of electromagnetic waves by the electromagnetic wave transmitting means, Information processing means (21) for performing processing for reading information stored in the RFID tag according to the electromagnetic wave received by the electromagnetic wave receiving means, and the RFID tag being processed per fixed time by the information processing means Detection means (21) for detecting the number of readings (N), and the RFID tag that can be processed per fixed time by the information processing means Storage means (22) for storing the number of readings as a limit reading number (N1), and determining whether or not the number of readings detected by the detection means is equal to or greater than the limit reading number stored in the storage means. A determination means (21) and a radio wave intensity adjustment means (21) for adjusting the radio wave intensity of the electromagnetic wave transmitted by the electromagnetic wave transmission means, wherein the radio wave intensity adjustment means detects the reading detected by the detection means. If the determination means determines that the number is equal to or greater than the limit reading number stored in the storage means, the radio wave intensity of the electromagnetic wave transmitted by the electromagnetic wave transmission means is reduced.
In addition, the code | symbol in each said parenthesis shows the correspondence with the specific means as described in embodiment mentioned later.

  According to the first aspect of the present invention, the reading number of the RFID tag processed per fixed time by the information processing means is detected by the detecting means, and the reading number detected by the detecting means is stored in the storage means. If the determination means determines that the number is greater than or equal to the number, the radio wave intensity of the electromagnetic wave transmitted by the electromagnetic wave transmission means is adjusted to be small by the radio wave intensity adjustment means.

  There is a limit to the number of RFID tags that can be processed by the information processing means per fixed time, and even if electromagnetic waves with high radio field intensity are transmitted so that more RFID tags can be read than this limit reading number. The number of RFID tags read by the information processing means per fixed time does not increase, and the RFID tag reading speed does not increase. In particular, when reading a large number of dense RFID tags, electromagnetic waves are often transmitted unnecessarily with high radio wave intensity.

  Therefore, if it is determined that the number of readings detected by the detecting means is equal to or greater than the limit reading number, the information processing means having a low processing capability is obtained by reducing the radio wave intensity of the electromagnetic waves transmitted by the electromagnetic wave transmitting means. In addition, it is possible to suppress electromagnetic waves from being transmitted with a uselessly large radio wave intensity. Therefore, it is possible to save power related to wireless communication according to the processing capability of the information processing means.

  In the invention of claim 2, when the determination means determines that the number of readings detected by the detection means is less than the limit reading number stored in the storage means, the radio wave intensity of the electromagnetic wave transmitted by the electromagnetic wave transmission means is It is greatly adjusted by the strength adjusting means.

  When the number of readings detected by the detection means is less than the limit reading number, the information processing means is in a processing load state with a margin for reading the RFID tag, so even if the radio wave intensity of the transmitted electromagnetic wave is increased. Electromagnetic waves are not transmitted with an unnecessarily large radio field intensity. For this reason, it is possible to increase the reading speed of the RFID tag while saving power related to wireless communication according to the processing capability of the information processing means.

  In the invention of claim 3, the number of readings detected by the detecting means is stored in the storage means after the radio wave intensity of the electromagnetic wave transmitted by the electromagnetic wave transmitting means is greatly adjusted by the radio wave intensity adjusting means to a predetermined maximum value. If it is determined by the determining means that the number is less than the limit reading number, the notification means prompts the mobile terminal to move.

  If the number of readings detected by the detection means is less than the limit reading number when the radio wave intensity of the transmitted electromagnetic wave is a predetermined maximum value, the RFID tag that can be read at the position of the portable terminal is almost read. There is a high possibility. That is, even when there are almost no readable RFID tags, electromagnetic waves are transmitted with a uselessly large radio wave intensity. In such a case, the notification means urges the mobile terminal to move, so that the remaining RFID tag that could not be read at the position of the mobile terminal can be read, and the radio wave having a large radio wave intensity wasted. Can be suppressed to save power related to wireless communication.

  In the invention of claim 4, the number of readings detected by the detection means is stored in the storage means after the radio wave intensity adjustment means has greatly adjusted the radio wave intensity of the electromagnetic wave transmitted by the electromagnetic wave transmission means to a predetermined maximum value. If it is determined by the determining means that the number is less than the limit reading number, the electromagnetic wave intensity of the electromagnetic wave transmitted by the electromagnetic wave transmitting means is adjusted to a predetermined minimum value.

  As described above, in the case where the notification means prompts the mobile terminal to move, it is unlikely that the RFID tag can be read until the mobile terminal moves. In such a case, by adjusting the radio wave intensity of the electromagnetic wave to a predetermined minimum value, it is possible to suppress the transmission of the electromagnetic wave with an unnecessarily large radio wave intensity and to save power related to wireless communication. .

  In the invention of claim 5, when the movement of the portable terminal is detected by the movement detection means after the notification for prompting the movement of the portable terminal is made by the notification means, the radio wave intensity of the electromagnetic wave transmitted by the electromagnetic wave transmission means is increased. It is greatly adjusted by the radio wave intensity adjusting means.

  As a result, it is estimated that the mobile terminal that has moved can read the remaining RFID tags. Therefore, the remaining RFID tags can be read by increasing the radio wave intensity of the electromagnetic waves that have been adjusted to a predetermined minimum value. It is possible to quickly shift to an easy state.

  In the invention of claim 6, the limit reading number stored in the storage means can be updated by the updating means in accordance with the detection result by the detecting means. For this reason, even when the information processing means performs not only the process of reading the RFID tag but also other processes, it is possible to set the limit number of readings according to the processing status, and electromagnetic waves are transmitted with a uselessly large radio wave intensity. It can be surely suppressed.

It is explanatory drawing which shows the structure outline | summary of the portable terminal which concerns on 1st Embodiment, FIG. 1 (A) shows a top view and FIG. 1 (B) shows a side view. 2A is a block diagram illustrating the electrical configuration of the mobile terminal in FIG. 1, and FIG. 2B is a block diagram schematically illustrating the non-contact communication unit in FIG. 2A. FIG. 2C is a block diagram schematically illustrating the information code reading unit in FIG. 2 is a block diagram schematically illustrating an electrical configuration of an RFID tag. FIG. It is a flowchart which illustrates the flow of the tag reading process by the control part which concerns on 1st Embodiment.

[First Embodiment]
Hereinafter, a first embodiment in which a portable terminal according to the present invention is embodied will be described with reference to the drawings.
The portable terminal 10 according to the present embodiment is configured as a portable information terminal that is carried by a user and used in various places, and is stored in the RFID tag 60 through an electromagnetic wave transmitted and received via an antenna. In addition to the function as an RFID tag reader / writer for reading and writing information, it also has a function as an information code reader for reading an information code such as a bar code or a two-dimensional code, and can be read in two ways.

  As shown in FIGS. 1 (A) and 1 (B), a portable terminal 10 is a longitudinal casing 11 formed by assembling an upper case 11a and a lower case 11b formed of a synthetic resin material such as ABS resin. The outer shell is formed by. The upper case 11a is provided with a key operation unit 25 such as function keys and numeric keys operated when inputting predetermined information, a display unit 24 for displaying predetermined information, and the like. The lower case 11b has a reading port 12 that opens downward.

  As shown in FIG. 2A, a control unit 21 that controls the entire mobile terminal 10 is provided in the housing 11 of the mobile terminal 10. The control unit 21 is composed mainly of a microcomputer, has a CPU, a system bus, an input / output interface, and the like, and constitutes an information processing apparatus together with the memory 22. A predetermined program or the like for executing a tag reading process, which will be described later, is stored in the memory 22 in advance so as to be executable by the control unit 21. The control unit 21 is connected to an LED 23, a display unit 24, a key operation unit 25, a vibrator 26, a buzzer 27, an acceleration sensor 28, an external interface 29, and the like.

  The key operation unit 25 is configured to give an operation signal to the control unit 21, and the control unit 21 receives the operation signal and performs an operation according to the content of the operation signal. Further, the LED 23, the display unit 24, the vibrator 26 and the buzzer 27 are configured to be controlled by the control unit 21, and each operate in response to a command from the control unit 21.

  The acceleration sensor 28 is a known three-axis acceleration sensor (three-axis motion sensor) capable of detecting acceleration in the three-axis direction, and detects acceleration in each of the X-axis direction, the Y-axis direction, and the Z-axis direction. The acceleration signal corresponding to the detection result is output to the control unit 21. This acceleration sensor 28 detects (calculates) the position and movement state of the mobile terminal 10 in the three-axis directions by detecting acceleration in the three-axis directions (X-axis direction, Y-axis direction, and Z-axis direction). can do.

  The external interface 29 is configured as an interface for performing data communication with an external device or the like, and is configured to perform communication processing in cooperation with the control unit 21. In addition, a power supply unit (not shown) is provided in the housing 11, and power is supplied to the control unit 21 and various electric components by the power supply unit, a battery, and the like.

The non-contact communication unit 30 and the information code reading unit 40 are connected to the control unit 21.
First, the non-contact communication unit 30 will be described with reference to FIG.
The non-contact communication unit 30 performs communication by electromagnetic waves with the RFID tag 60 in cooperation with the antenna 34 and the control unit 21, reads data stored in the RFID tag 60, or writes data to the RFID tag 60. It functions to perform. The non-contact communication unit 30 is configured as a circuit that performs transmission by a known radio wave system. As schematically illustrated in FIG. 2B, the non-contact communication unit 30 includes a transmission circuit 31, a reception circuit 32, a matching circuit 33, and the like. Have.

  The transmission circuit 31 includes a carrier oscillator, an encoding unit, an amplifier, a transmission unit filter, a modulation unit, and the like, and is configured to output a carrier (carrier wave) having a predetermined frequency from the carrier oscillator. The encoding unit is connected to the control unit 21, encodes transmission data output from the control unit 21, and outputs the transmission data to the modulation unit. The modulation unit is a part to which the carrier (carrier wave) from the carrier oscillator and the transmission data from the encoding unit are input. The carrier (carrier wave) output from the carrier oscillator is encoded at the time of command transmission to the communication target. A modulated signal that is ASK (Amplitude Shift Keying) modulated by the encoded transmission code (modulated signal) output from the encoding unit is generated and output to the amplifier. The amplifier amplifies the input signal (the modulated signal modulated by the modulation unit) with a predetermined gain, and outputs the amplified signal to the transmission unit filter. The transmission unit filter filters the amplified signal from the amplifier. The transmission signal is output to the antenna 34 via the matching circuit 33. When a transmission signal is output to the antenna 34 in this way, the transmission signal is radiated to the outside from the antenna 34 as an electromagnetic wave. The non-contact communication unit 30 that transmits electromagnetic waves in this way can correspond to an example of “electromagnetic wave transmission means”.

  On the other hand, the electromagnetic wave received as a response signal by the antenna 34 is input to the receiving circuit 32 via the matching circuit 33. The receiving circuit 32 includes a receiving unit filter, an amplifier, a demodulating unit, a binarization processing unit, a decoding unit, and the like. After the response signal received through the antenna 34 is filtered by the receiving unit filter, The signal is amplified by an amplifier, and the amplified signal is demodulated by a demodulator. The demodulated signal waveform is binarized by the binarization processing unit, decoded by the decoding unit, and then the decoded signal is output to the control unit 21 as received data. The non-contact communication unit 30 that receives electromagnetic waves in this way corresponds to an example of “electromagnetic wave receiving means”, and the control unit 21 can correspond to an example of “information processing means”.

Here, the electrical configuration of the RFID tag 60 to be read by the mobile terminal 10 will be described with reference to FIG.
As shown in FIG. 3, the RFID tag 60 includes an antenna 61, a power supply circuit 62, a demodulation circuit 63, a control circuit 64, a memory 65, a modulation circuit 66, and the like. The power supply circuit 62 rectifies and smoothes a transmission signal (carrier signal) received from the portable terminal 10 received via the antenna 61 to generate an operation power supply. The operation power supply includes the control circuit 64 and the like. Is supplied to each component.

  The demodulating circuit 63 demodulates data superimposed on the transmission signal (carrier signal) and outputs the demodulated data to the control circuit 64. The memory 65 is configured by various semiconductor memories such as ROM and EEPROM, and stores control information, identification information (tag ID) for identifying the RFID tag 60, data corresponding to the use of the RFID tag 60, and the like. ing. The control circuit 64 is configured to read the information and data from the memory 65 and output it as transmission data to the modulation circuit 66. The modulation circuit 66 performs load modulation on the response signal (carrier signal) with the transmission data. Then, the antenna 61 is configured to transmit as a reflected wave (electromagnetic wave).

Next, the information code reading unit 40 will be described with reference to FIG.
The information code reading unit 40 functions to optically read the information code. As shown in FIG. 2C, the information code reading unit 40 includes a light receiving sensor 43 including a CCD area sensor, an imaging lens 42, a plurality of LEDs, It has a configuration including an illumination unit 41 composed of a lens or the like, and reads an information code C (bar code, two-dimensional code, etc.) attached to the reading object R in cooperation with the control unit 21. Function.

  When reading is performed by the information code reading unit 40, first, the illumination light Lf is emitted from the illumination unit 41 that has been instructed by the control unit 21, and the illumination light Lf is irradiated to the reading object R through the reading port 12. The Then, the reflected light Lr reflected by the information code C from the illumination light Lf is taken into the apparatus through the reading port 12 and is received by the light receiving sensor 43 through the imaging lens 42. The imaging lens 42 disposed between the reading port 12 and the light receiving sensor 43 is configured to form an image of the information code C on the light receiving sensor 43, and the light receiving sensor 43 is an image of the information code C. The light reception signal corresponding to the is output. The light receiving signal output from the light receiving sensor 43 is stored as image data in the memory 22 (FIG. 2A) and used for decoding processing for acquiring information included in the information code C. The information code reading unit 40 is provided with an amplifying circuit for amplifying the signal from the light receiving sensor 43 and an AD converting circuit for converting the amplified signal into a digital signal. Is omitted.

Next, a tag reading process executed by the control unit 21 at the time of inventory work using the mobile terminal 10 will be described.
In the inventory work, it is necessary to read a large number of RFID tags 60 each attached to a dense product. On the other hand, there is a limit to the number of RFID tags 60 that can be read by the control unit 21 per certain time (unit time), and the number of readings that is the limit (hereinafter also referred to as the limit reading number N1). Is mainly determined by the performance of the control unit 21. For this reason, even if a large number of RFID tags 60 are detected by the non-contact communication unit 30 transmitting an electromagnetic wave having a large radio wave intensity so that a larger number of RFID tags 60 than the limit reading number N1 are targeted for reading. The number of RFID tags 60 read by the control unit 21 is not increased per time, and the reading speed of the RFID tags 60 is not increased. In other words, if the number of readings is equal to or greater than the limit reading number N1, there is a high possibility that electromagnetic waves are transmitted with an unnecessarily large radio wave intensity.

  Therefore, in the present embodiment, in order to save power by suppressing transmission of electromagnetic waves with an unnecessarily large radio wave intensity, a limit reading number N1 per predetermined time according to the performance of the control unit 21 is set in advance. Stored in the memory 22. Then, in accordance with the comparison result between the limit reading number N1 and the number of RFID tags 60 that are actually read by the control unit 21 per certain period of time (hereinafter also referred to as the reading number N), contactlessness is achieved. The radio wave intensity of the electromagnetic wave transmitted by the communication unit 30 is adjusted. In particular, in the present embodiment, when a large number of RFID tags 60 are detected, the maximum number of readings per fixed time by the reading process of the control unit 21 is measured, and this actually measured maximum reading number is the limit reading. The number N1 is stored in the memory 22. For example, if 500 RFID tags 60 are read when the predetermined time is 10 seconds, the limit reading number N1 is set to a value equal to or slightly smaller than the reading number 500 and stored in the memory 22. Remembered. The memory 22 may correspond to an example of “storage means”.

Hereinafter, a tag reading process for reading the RFID tag 60 in a state where the radio wave intensity of the electromagnetic wave transmitted from the non-contact communication unit 30 is adjusted based on the reading number N and the limit reading number N1 will be described in detail with reference to the flowchart of FIG. Describe.
When the tag reading process is started by the control unit 21 by performing a predetermined operation on the key operation unit 25, the electromagnetic wave transmitted by the non-contact communication unit 30 in the process shown in step S101 of FIG. Is adjusted to a predetermined maximum value in consideration of the reading environment and the like. Subsequently, a process for detecting the RFID tag 60 is performed in step S103, and a large amount of data of the RFID tag 60 is detected and collected using the electromagnetic wave having the adjusted radio wave intensity.

  Next, in the process shown in step S105, the number of readings N of the RFID tags 60 that are read by the control unit 21 for a certain time with respect to the large number of RFID tags 60 detected as described above is detected. The control unit 21 that performs the process of step S105 may correspond to an example of a “detection unit”.

  Subsequently, in the determination process shown in step S <b> 107, it is determined whether or not the detected reading number N of the RFID tag 60 is equal to or greater than the limit reading number N <b> 1 stored in the memory 22. Here, if the reading number N is equal to or greater than the limit reading number N1 (Yes in S107), it is determined that electromagnetic waves are transmitted with a uselessly large radio wave intensity, and non-contact communication is performed in the process shown in step S109. The radio wave intensity of the electromagnetic wave transmitted by the unit 30 is adjusted to be lowered by one step. The control unit 21 that performs the determination process in step S107 corresponds to an example of a “determination unit”, and the control unit 21 that performs the process in step S109 and the process in step S115 described later is “a radio wave intensity adjustment unit”. It may correspond to an example.

  If the state in which the RFID tag 60 is detected is continued even if the radio field intensity is lowered by one step, it is determined Yes in step S111, and the processing from step S103 is performed. That is, while the state where the reading number N is equal to the limit reading number N1 is continued (Yes in S107), the radio wave intensity of the electromagnetic wave transmitted by the non-contact communication unit 30 is adjusted to be lowered stepwise. When the reading number N becomes less than the limit reading number N1, the adjustment for reducing the radio field intensity is stopped (No in S107). The electromagnetic wave at the radio wave intensity when the read number N is less than the limit read number N1 is not a useless high radio wave intensity, but a radio wave intensity suitable for the reading environment and the like in order to save power. .

  When the reading number N becomes less than the limit reading number N1 in a state where the electromagnetic wave intensity is gradually reduced from the maximum value (No in S107), the electromagnetic wave intensity of the electromagnetic wave is determined in the determination process shown in step S113. Is not the above maximum value, it is determined No. In this case, since the control unit 21 is in a processing load state with a margin for reading the RFID tag 60, even if the radio wave intensity of the transmitted electromagnetic wave is increased, the electromagnetic wave is transmitted unnecessarily with a high radio wave intensity. Nor. For this reason, for the purpose of improving the reading speed, in the process shown in step S115, the radio wave intensity of the electromagnetic wave transmitted by the non-contact communication unit 30 is adjusted to be increased by one step. If the state in which the RFID tag 60 is detected is continued, “Yes” is determined in step S111, and the processing from step S103 is repeated.

  If the number of readings N is less than the limit reading number N1 during the repetitive processing from step S103 and the radio wave intensity that has been increased stepwise reaches the maximum value, it is determined Yes in step S113. When the read number N detected when the radio wave intensity of the transmitted electromagnetic wave is the above maximum value is less than the limit read number N1, the RFID tag 60 that can be read at the position of the mobile terminal 10 is almost read. There is a high possibility. That is, even when there is almost no readable RFID tag 60, electromagnetic waves are transmitted with a uselessly large radio wave intensity. On the other hand, if all the RFID tags 60 that can be read at the position of the mobile terminal 10 are read during the iterative processing from step S103, it is determined No in step S111.

  As described above, when it is determined Yes in step S113 or No in step S111, a notification process shown in step S117 is performed. In this process, information indicating that there is no detectable RFID tag 60 in the surroundings and information for prompting movement to read another unread RFID tag 60 are displayed on the display unit 24 to be notified. This notification may be performed using not only the display 24 but also the lighting state of the LED 23, the vibration of the vibrator 26, the sound of the buzzer 27, and the like. The display unit 24, the LED 23, the vibrator 26, the buzzer 27, and the like may correspond to an example of “notification unit”.

  After such notification, in the process shown in step S119, the radio wave intensity of the electromagnetic wave transmitted by the non-contact communication unit 30 is adjusted to a predetermined minimum value considering the reading environment and the like. This is because in the state where there is almost no readable RFID tag 60, it is highly possible that electromagnetic wave transmission itself is wasted. In the process shown in step S119, the transmission of electromagnetic waves by the non-contact communication unit 30 can be stopped.

  Then, in the determination process shown in step S121, it is determined whether or not the mobile terminal 10 is moving based on the detection result of the acceleration sensor 28. Here, when the movement of the mobile terminal 10 is not detected, the determination of No is repeated in step S121, and the radio wave intensity of the electromagnetic wave transmitted by the non-contact communication unit 30 is adjusted to the minimum value. Will continue. The control unit 21 and the acceleration sensor 28 that perform the determination process in step S121 may correspond to an example of “movement detection unit”.

  Thereafter, when the user who has received the notification moves the mobile terminal 10, the movement of the mobile terminal 10 is detected based on the detection result of the acceleration sensor 28, and “Yes” is determined in step S <b> 121. If all the RFID tags 60 have not been read (No in S123), the processing from Step S101 is performed, and the radio wave intensity of the electromagnetic wave transmitted by the non-contact communication unit 30 is adjusted to the maximum value. In this state, the process for reading the remaining RFID tag 60 at the destination is continued.

  As described above, in the mobile terminal 10 according to this embodiment, the reading number N of the RFID tag 60 processed per certain time is detected by the control unit 21 (S105), and the detected reading number N Is determined to be equal to or greater than the limit reading number N1 stored in the memory 22 (Yes in S107), the radio wave intensity of the electromagnetic wave transmitted by the non-contact communication unit 30 is adjusted to be small (S109).

  As described above, when it is determined that the detected reading number N is equal to or greater than the limit reading number N1, the control unit 21 having low processing capability is obtained by reducing the radio wave intensity of the electromagnetic wave transmitted by the non-contact communication unit 30. Even so, it is possible to prevent electromagnetic waves from being transmitted with a uselessly large radio wave intensity. Therefore, it is possible to save power related to wireless communication according to the processing capability of the control unit 21.

  If it is determined that the detected reading number N is less than the limit reading number N1 stored in the memory 22 (No in S107), the radio wave intensity of the electromagnetic wave transmitted by the non-contact communication unit 30 is greatly adjusted. (S115). As described above, when the detected reading number N is less than the limit reading number N1, the control unit 21 is in a processing load state with a margin for reading the RFID tag 60, and thus the reading number N and the limit reading number N1. By appropriately increasing the radio wave intensity of the electromagnetic wave transmitted based on the comparison result, the reading speed of the RFID tag 60 can be increased while saving power related to wireless communication according to the processing capability of the control unit 21. Can do.

  Further, after the radio wave intensity of the electromagnetic wave transmitted by the non-contact communication unit 30 is largely adjusted to the maximum value, it is determined that the detected reading number N is less than the limit reading number N1 stored in the memory 22. Then (Yes in S113), notification for prompting the movement of the mobile terminal 10 is performed by display by the display unit 24 (S117).

  As described above, when the RFID tag 60 that can be read at the position of the mobile terminal 10 has been almost read, by notifying the mobile terminal 10 to move, the position of the mobile terminal 10 thus far Thus, the remaining RFID tag 60 that could not be read can be read, and transmission of radio waves with a large radio wave intensity can be suppressed to save power related to wireless communication.

  Furthermore, after the radio wave intensity of the electromagnetic wave transmitted by the non-contact communication unit 30 is largely adjusted to the maximum value, it is determined that the detected reading number N is less than the limit reading number N1 stored in the memory 22. If it is (Yes in S113), the radio wave intensity of the electromagnetic wave transmitted by the non-contact communication unit 30 is adjusted to the minimum value (S119).

  Thus, when the possibility that the RFID tag 60 can be read is low until the mobile terminal 10 moves, the electromagnetic wave intensity is unnecessarily increased by adjusting the radio wave intensity of the electromagnetic wave to the minimum value. Can be suppressed to save power related to wireless communication.

  In particular, the electromagnetic wave transmitted by the non-contact communication unit 30 when the movement of the mobile terminal 10 is detected after the notification for urging the mobile terminal 10 is made by the display of the display unit 24 or the like (Yes in S121). Is greatly adjusted (S101).

  As a result, it is presumed that the mobile terminal 10 that has moved can read the remaining RFID tag 60. Therefore, by increasing the radio wave intensity of the electromagnetic wave adjusted to the minimum value, the remaining RFID tag 60 can be read. It is possible to quickly shift to a state where it is easy to read.

[Other Embodiments]
In addition, this invention is not limited to the said embodiment, For example, you may actualize as follows.
(1) The limit reading number N1 stored in the memory 22 may be updatable. For example, in an environment where the control unit 21 performs another process such as a communication process different from the process of reading the RFID tag 60 in parallel, the processing load of the control unit 21 is likely to fluctuate. In such a case, for example, at the start of the reading operation, the maximum number of readings per a predetermined time by the reading process of the control unit 21 is actually measured, which is equal to or slightly smaller than the actually measured maximum number of readings. The limit reading number N1 stored in the memory 22 can be updated so as to be a small numerical value. Thereby, even when the control unit 21 performs not only the process of reading the RFID tag 60 but also other processes, the limit reading number N1 corresponding to the processing state can be set (updated), and electromagnetic waves are generated with a uselessly large radio wave intensity. It is possible to reliably suppress transmission. The control unit 21 that performs the update process may correspond to an example of “update means”.

(2) In the above embodiment, one limit reading number N1 is prepared in advance and stored in the memory 22. However, the present invention is not limited to this, and the limit reading number N1 of a plurality of patterns corresponding to the processing load of the control unit 21 is determined. It may be prepared in advance and stored in the memory 22. Thus, by selecting the optimum limit reading number N1 according to the processing load of the control unit 21 during the tag reading process, it is possible to adjust the radio wave intensity of the electromagnetic wave more realistically with respect to power saving.

(3) In step S119, the radio wave intensity of the electromagnetic wave transmitted by the non-contact communication unit 30 is not limited to the minimum value, and the same as in step S109 until the movement of the mobile terminal 10 is detected. The radio wave intensity may be adjusted so as to be lowered step by step.

10 ... mobile terminal 21 ... control unit (information processing means, detection means, determination means, radio wave intensity adjustment means, update means)
22 ... Memory (storage means)
24 ... Display section (notification means)
28 ... Acceleration sensor (movement detection means)
30 ... Non-contact communication part (electromagnetic wave transmission means, electromagnetic wave reception means)
60 ... RFID tag N ... Number of readings N1 ... Limit reading number

Claims (6)

A portable terminal that reads information stored in the RFID tag by wireless communication with the RFID tag,
Electromagnetic wave transmitting means for transmitting electromagnetic waves to the RFID tag;
An electromagnetic wave receiving means for receiving an electromagnetic wave transmitted from the RFID tag in response to transmission of the electromagnetic wave by the electromagnetic wave transmitting means;
Information processing means for performing processing for reading information stored in the RFID tag in accordance with electromagnetic waves received by the electromagnetic wave receiving means;
Detection means for detecting the number of read RFID tags being processed per a certain time by the information processing means;
Storage means for storing, as a limit reading number, the number of readings of the RFID tag that can be processed by the information processing means per fixed time;
Determination means for determining whether or not the number of readings detected by the detection means is equal to or greater than the limit reading number stored in the storage means;
Radio wave intensity adjusting means for adjusting the radio wave intensity of the electromagnetic wave transmitted by the electromagnetic wave transmitting means,
The radio wave intensity adjusting means transmits the electromagnetic wave transmitting means when the determining means determines that the read number detected by the detecting means is greater than or equal to the limit read number stored in the storage means. A portable terminal characterized by reducing the radio wave intensity of electromagnetic waves.   The radio wave intensity adjusting means transmits the electromagnetic wave transmitting means when the determining means determines that the read number detected by the detecting means is less than the limit read number stored in the storage means. The mobile terminal according to claim 1, wherein the radio wave intensity of the electromagnetic wave is increased.   The read number detected by the detecting means is stored in the storage means after the radio wave intensity of the electromagnetic wave transmitted by the electromagnetic wave transmitting means is greatly adjusted to a predetermined maximum value by the radio wave intensity adjusting means. The mobile terminal according to claim 2, further comprising a notification unit that performs notification that prompts the mobile terminal to move when the determination unit determines that the number is less than the limit reading number.   The radio wave intensity adjusting unit adjusts the radio wave intensity of the electromagnetic wave transmitted by the electromagnetic wave transmitting unit to the predetermined maximum value, and then stores the number of readings detected by the detecting unit in the storage unit. The radio wave intensity of the electromagnetic wave transmitted by the electromagnetic wave transmission unit is adjusted to a predetermined minimum value when the determination unit determines that the number is less than the limit reading number. Mobile device. Comprising a movement detecting means for detecting movement of the portable terminal;
The radio wave intensity adjusting means detects an electromagnetic wave transmitted by the electromagnetic wave transmitting means when the movement detecting means detects the movement of the portable terminal after the notifying means is instructed to urge the portable terminal to move. The portable terminal according to claim 4, wherein the radio wave intensity is increased.   The mobile terminal according to claim 1, further comprising an updating unit capable of updating the limit reading number stored in the storage unit according to a detection result by the detecting unit.

Images