JP2005229474A - Information terminal device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an information terminal device which is capable of matching a resonant frequency of an antenna with a desired frequency even after a housing of the information terminal device is closed. <P>SOLUTION: The information terminal device 1 comprises a trimmer capacitor 52 which functions as a frequency adjustment means for adjusting a resonant frequency of the antenna 5 under control from the outside of the housing of the information terminal device 1. The antenna 5 comprises a coil 51 which forms a resonance circuit together with the trimmer capacitor 52, and a resonant frequency of the resonance circuit is adjusted into desired frequency by increasing/decreasing capacitance of the trimmer capacitor 52 from the outside of the housing after the housing of the information terminal device 1 is closed. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an information terminal device that includes an antenna that transmits and receives predetermined radio waves and performs non-contact information reading processing or information writing processing on an external information medium.

  Conventionally, an RFID (Radio Frequency Identification) system has been developed as one of radio communication systems. The RFID system includes an RFID tag that stores identification information and the like, and an information terminal device that performs information reading processing and information writing processing on the RFID tag by performing wireless communication with the RFID tag.

  The RFID tag includes a small integrated circuit and an antenna for wireless communication. The RFID tag is attached to a management target, receives an operating power source by receiving a radio wave of a predetermined frequency transmitted from the information terminal device, and starts wireless communication with the information terminal device. In addition, the information terminal device includes an antenna that transmits and receives radio waves of a predetermined frequency in order to supply power to the RFID tag and transmit and receive information, and a control unit that controls wireless communication (see Patent Document 1). Then, the information terminal device identifies the target to which the RFID tag is attached by receiving a transmission radio wave from the RFID tag or by whether or not the RFID tag antenna resonates with a radio wave of a specific frequency. I manage.

  An antenna of an information terminal device includes, for example, a coil that transmits and receives radio waves of a predetermined frequency, and a capacitor that forms a resonance circuit with the coil. The resonance frequency of the resonance circuit, that is, the frequency of the radio wave transmitted by the coil is set to a desired frequency by adjusting the inductance of the coil and the capacitance of the capacitor. Since the resonance circuit is also affected by the parasitic capacitance generated in the antenna, the capacitance of the capacitor and the inductance of the coil are set in consideration of the parasitic capacitance. Further, in order to efficiently transmit signals between the control unit and the antenna, it is necessary to match the impedances of the antenna and the control unit. In addition, the antenna may include a matching circuit including a predetermined resistance that takes into account the capacitance of the capacitor and the inductance of the coil and the like in order to match the impedance of the antenna and the control unit.

JP 2001-34725 A (FIG. 6)

  However, in the conventional information terminal device, after the housing of the information terminal device including the antenna and the control unit is closed, the frequency of the transmission radio wave, that is, the resonance frequency fluctuates with respect to the desired frequency, and is desired from the antenna. There was a case where radio waves of the frequency of could not be transmitted. In this case, there is a problem that transmission power from the information terminal device is reduced and stable supply of power to the RFID tag cannot be performed, and information reading processing or information writing processing cannot be accurately performed on the RFID tag. .

  Such fluctuations in the resonance frequency are caused by fluctuations in the inductance and parasitic capacitance of the coil caused by the influence of the surrounding environment. Inductance and parasitic capacitance fluctuate even when substances having different magnetic permeability and dielectric constant are installed in the vicinity. For example, when the antenna is attached to the casing of the information terminal device, the positional relationship between the antenna and components around the antenna may be shifted from the initial setting. Due to such positional deviation, parasitic capacitance and inductance change, and the resonance frequency in the resonance circuit formed by the coil and conductance changes. However, conventionally, it has been difficult to adjust the resonance frequency after closing the casing of the information terminal device. In addition, fluctuations in the inductance and parasitic capacitance of the coil cause fluctuations in the impedance of the antenna. As a result, the impedance between the antenna and the control unit does not match and reflection occurs, which may deteriorate the signal transmission efficiency.

  The present invention has been made in view of the above-described drawbacks of the prior art, and is an information terminal capable of matching the resonance frequency of an antenna with a desired frequency even after the housing of the information terminal apparatus is closed. An object is to provide an apparatus.

  An information terminal device according to claim 1 includes an antenna that transmits and receives a predetermined radio wave, and performs an information reading process or an information writing process in a non-contact manner with respect to an external information medium. A frequency adjusting means for adjusting the frequency is provided inside the casing, and an adjustment space from a hole provided in the casing to the frequency adjusting means is provided.

  According to the information terminal device of the present invention, the frequency adjusting means for adjusting the resonance frequency of the antenna is provided inside the casing, and the adjustment space from the hole provided in the casing to the frequency adjusting means is provided. Even after the casing of the terminal device is closed, the resonance frequency of the antenna can be adjusted from the hole provided in the casing through the adjustment space.

  The information terminal device according to claim 2 is characterized in that the frequency adjusting means is a variable capacitor forming a resonance circuit of the antenna.

  The information terminal device according to claim 3 is characterized in that the frequency adjusting means is a variable coil forming a resonance circuit of the antenna.

  The information terminal device according to claim 4 is characterized in that the frequency adjusting means is a variable coil and a variable capacitor forming a resonance circuit of the antenna.

  The information terminal device according to claim 5, wherein the housing includes a lid portion that closes a recessed space formed in the housing itself, and the hole is provided on the housing side of the recessed space. To do.

  The information terminal device according to claim 6 is characterized in that the hole is sealed with a sealing member after the resonance frequency is adjusted.

  The information terminal device according to a seventh aspect is characterized in that the lid portion includes a waterproof mechanism for waterproofing the recessed space.

  The information terminal device according to claim 8 includes a control unit that performs the information reading process or the information writing process, an input unit that inputs instruction information of the information reading process or the information writing process, and the information reading process. Display means for displaying information read from the information medium or information written to the information medium by the information writing process, and the control means includes an RFID processing unit for controlling the driving of the antenna; And a control unit that performs processing control of the information reading process or the information writing process on the RFID processing unit based on the instruction information input from the input unit.

  An information terminal device according to a ninth aspect includes optical information reading means for optically reading information on the information medium, and the input means receives instruction information for processing in which the optical information reading means optically reads the information. The control unit controls the optical information reading unit to control the processing of the optical reading unit.

  According to the information terminal device of the present invention, the frequency adjusting means for adjusting the resonance frequency of the antenna is provided inside the casing, and the adjustment space from the hole provided in the casing to the frequency adjusting means is provided. Even after the casing of the terminal device is closed, the resonance frequency of the antenna can be adjusted from the hole provided in the casing through the adjustment space. For this reason, the information terminal device according to the present invention can match the resonance frequency of the antenna to a desired frequency even after the housing of the information terminal device is closed, and is non-contact with an external information medium. It is possible to accurately perform the information reading process or information writing process.

  Hereinafter, an information terminal device that performs non-contact information reading processing or information writing processing on an RFID tag will be described as an example of an information terminal device according to an embodiment of the present invention with reference to the drawings. Note that the present invention is not limited to the embodiments. In the description of the drawings, the same parts are denoted by the same reference numerals.

(Embodiment)
First, an information terminal device according to an embodiment will be described. The information terminal device according to the present embodiment is provided with frequency adjusting means for adjusting the resonance frequency of the antenna inside the casing and an adjustment space from the hole provided in the casing to the frequency adjusting means. . FIG. 1 is a block diagram showing a schematic configuration of the information terminal device 1 according to the present embodiment.

  In FIG. 1, an information terminal device 1 includes an input unit 2, an external communication unit 3, a storage device 4, a wireless communication antenna 5, an RFID processing unit 6, an optical information reading unit 7, and a display unit 8. A voice input / output unit 9, a control unit 10, and a storage unit 10a. The input unit 2, the external communication unit 3, the storage device 4, the RFID processing unit 6, the optical information reading unit 7, the display unit 8, the voice input / output unit 9, and the storage unit 10a are electrically connected to the control unit 10, The antenna 5 is electrically connected to the RFID processing unit 6. The control unit 10 also controls the input unit 2, the external communication unit 3, the storage device 4, the RFID processing unit 6, the optical information reading unit 7, the display unit 8, the voice input / output unit 9, and the storage unit 10a.

  The input unit 2 includes instruction information (read instruction information) for instructing processing (information reading processing) for reading information stored in the RFID tag, information (write information) to be written to the RFID tag, and write information to the RFID tag. Instruction information including instruction information for instructing processing for writing (information writing processing), or instruction information for instructing processing for reading information on an external optical information recording medium (optical information reading processing) (optical reading instruction information) ) And a plurality of input keys, etc., are arranged in the device casing of the information terminal device 1. For example, when the operator performs a key operation or the like for inputting the read instruction information using the input key or the like of the input unit 2, the input unit 2 receives the input of the read instruction information and the received read instruction information. Is sent to the control unit 10. In addition, when the operator performs a key operation or the like for inputting the write instruction information using the input key or the like of the input unit 2, the input unit 2 receives the input of the write instruction information and the received document. Information is sent to the control unit 10. When the operator performs a key operation or the like for inputting the optical reading instruction information using the input key or the like of the input unit 2, the input unit 2 receives the input of the optical reading instruction information and the received optical Read instruction information is sent to the control unit 10.

  The external communication unit 3 is realized using an external communication interface such as RS232C, USB, or IEEE1394, or an infrared communication interface conforming to the IrDA standard, and performs information communication with an external host computer (not shown) or the like. . When the information read by the information reading process is input from the control unit 10, the external communication unit 3 transmits the information input from the control unit 10 to an external host computer or the like under the control of the control unit 10. Send it out. Further, when various information for controlling the processing operation of the control unit 10 is input from an external host computer, the external communication unit 3 sends the information input from the external host computer to the control unit 10.

  The storage device 4 functions to record information input from the control unit 10 under the control of the control unit 10 on a storage medium detachably inserted into the storage device 4 by an operator. The storage device 4 functions to read information stored in the recording medium under the control of the control unit 10. Various storage media such as a compact flash (registered trademark) card, a smart media, a memory stick, a multimedia card, and an SD memory card are used as a storage medium that is detachably inserted into the storage device 4.

  The antenna 5 functions to transmit and receive radio waves of a predetermined frequency with an RFID tag existing in a predetermined communication area under the control of the RFID processing unit 6. In this case, the antenna 5 transmits a radio wave having a predetermined frequency corresponding to the electrical signal input from the RFID processing unit 6 or receives a predetermined radio wave transmitted from the RFID tag and receives the received predetermined radio wave. The electric signal corresponding to is sent to the RFID processing unit 6. As will be described later, the information terminal device 1 according to the present embodiment is provided with frequency adjusting means for adjusting the resonance frequency of the antenna 5, and the resonance frequency of the antenna 5 closes the casing of the information terminal device 1. Even after, adjustment is performed by the frequency adjusting means.

  The RFID processing unit 6 demodulates a signal received via the antenna 5 and a function of transmitting an electric signal to the antenna 5 to transmit a radio wave of a predetermined frequency from the antenna 5 under the control of the control unit 10. With functions. In this case, the RFID processing unit 6 controls an electrical signal transmitted to the antenna 5 to transmit a radio wave of a predetermined frequency from the antenna 5 and receive a radio wave of a predetermined frequency via the antenna 5 to the RFID tag. Then, non-contact information reading processing or information writing processing is performed. The RFID processing unit 6 functions to perform an information reading process or an information writing process on the RFID tag via a predetermined radio wave transmitted and received between the antenna 5 and the RFID tag.

  For example, when the reading instruction information input from the input unit 2 is sent to the RFID processing unit 6 via the control unit 10, the RFID processing unit 6 converts the reading instruction information under the control of the control unit 10. Modulate as necessary. Thereafter, an electric signal corresponding to the reading instruction information is transmitted to the antenna 5 and a control for transmitting a predetermined radio wave corresponding to the electric signal to the antenna 5 is performed. In this case, the antenna 5 transmits a predetermined radio wave corresponding to the electric signal to the RFID tag under the control of the RFID processing unit 6. Next, the antenna 5 receives a predetermined radio wave output from the RFID tag based on the instruction of the reading instruction information, and sends an electrical signal corresponding to the received predetermined radio wave to the RFID processing unit 6. Here, the predetermined radio wave received from the RFID tag corresponds to information stored in the RFID tag. Therefore, the RFID processing unit 6 receives an electrical signal corresponding to the information stored in the RFID tag from the antenna 5. Thereafter, the RFID processing unit 6 demodulates the electric signal input from the antenna 5 as necessary, and uses the information obtained based on the electric signal as information stored in the RFID tag. To send. Thereby, the RFID processing unit 6 achieves information reading processing for the RFID tag.

  On the other hand, when the write instruction information input from the input unit 2 is sent to the RFID processing unit 6 through the control unit 10, the RFID processing unit 6 controls the write instruction under the control of the control unit 10. The electrical signal corresponding to the information is modulated as necessary. Thereafter, the RFID processing unit 6 transmits the electric signal to the antenna 5 and controls the antenna 5 to transmit a predetermined radio wave corresponding to the electric signal. The antenna 5 transmits a predetermined radio wave corresponding to the electric signal to the RFID tag under the control of the RFID processing unit 6. In this case, the RFID tag receives the write instruction information via a predetermined radio wave transmitted to and received from the antenna 5, and the write instruction information is received under the instruction of the received write instruction information. Write information corresponding to is stored or overwritten. Thus, the RFID processing unit 6 achieves information writing processing on the RFID tag.

  When the control unit 10 receives the optical reading instruction information from the input unit 2, the optical information reading unit 7 performs an optical information reading process on the optical information recording medium under the control of the control unit 10. The optical information reading unit 7 performs an imaging process on the optical information recording medium, decodes image information obtained by the imaging process, reads information on the optical information recording medium, and sends the read information to the control unit 10. An optical information reading process is achieved. The optical information reading unit 7 is realized by using a CCD (Charge Coupled Diode), a CMOS (Complementary Metal Oxide Semiconductor), etc., and a photoelectric conversion unit that converts the formed input light into an electric signal, and an incident from the photoelectric conversion unit And an optical system for imaging light. The optical information reading unit includes a light source such as a semiconductor laser element or a light emitting diode that projects infrared light or visible light on the optical information recording medium, and an image sensor that receives reflected light from the optical information recording medium. Or it can implement | achieve using light receiving elements, such as a photosensor. In this case, the optical information reading unit 7 projects infrared light or visible light onto the optical information recording medium, receives reflected light from the optical information recording medium, and uses the reflected light as the optical information recording medium. The information on the recording medium is read, and the read information is sent to the control unit 10.

  The display unit 8 is realized using, for example, a liquid crystal display (LCD), and under the control of the control unit 10, the information read by the information reading process and the writing included in the write instruction information Information or information read by the optical information reading process is displayed and output. Further, the display unit 8 displays and outputs the image information captured by the optical information reading unit 7 when the optical information reading unit 7 functions to image the optical information recording medium. In addition, the display part 8 may display and output the predetermined | prescribed error display which alert | reports this error under control of the control part 10, when the error regarding processing operation generate | occur | produces in the information terminal device 1. FIG.

  The voice input / output unit 9 is realized using a microphone and a speaker. Under the control of the control unit 10, the audio input / output unit 9 inputs external audio information and sends the input audio information to the control unit 10. Further, the voice input / output unit 9 outputs the voice information input from the control unit 10 to the outside under the control of the control unit 10. The voice input / output unit 9 outputs a predetermined notification sound for notifying the start or completion of processing by each component under the control of the control unit 10, or there is an error related to processing operation in the information terminal device 1. When this occurs, a predetermined error sound for notifying this error may be output under the control of the control unit 10. In this case, the voice input / output unit 9 outputs an error sound corresponding to the error display in synchronization with the output of the error display by the display unit 8 described above.

  The control unit 10 includes a storage unit 10a. The storage unit 10a includes a ROM (Read Only Memory) in which various data such as processing programs are stored in advance, various processing parameters, various information read from an RFID tag or an optical information recording medium, writing information, or audio. This is realized using a RAM (Random Access Memory) that stores information and the like. The control unit 10 is realized using a CPU (Central Processing Unit) that executes a processing program stored in the storage unit 10a. As described above, the input unit 2, the external communication unit 3, the storage device 4, and the RFID processing unit. 6. Control each process or operation of the optical information reading unit 7, the display unit 8, the voice input / output unit 9, and the storage unit 10a. In this case, the control unit 10 performs predetermined input / output control on information input / output to / from each of these components and performs predetermined information processing on this information. The control unit 10 sends information input from the RFID processing unit 6 or the optical information reading unit 7 to an external host computer via the external communication unit 3, and then information processing is performed by the host computer. Information may be received.

  Next, the configuration of the antenna 5 will be described in detail. FIG. 2 is a block diagram showing the configuration of the antenna 5. As shown in FIG. 2, the antenna 5 includes a coil 51, a trimmer capacitor 52 connected to the coil 51, and a terminal unit 58 electrically connected to the RFID processing unit 6. The coil 51 functions as an antenna element that transmits and receives radio waves of a predetermined frequency, and is formed by, for example, winding a conductor in a loop shape.

  The trimmer capacitor 52 functions as a frequency adjusting unit that adjusts the resonance frequency of the antenna 5. The trimmer capacitor 52 has two electrodes facing each other and a dielectric provided between these electrodes, and the capacitance can be increased or decreased by increasing or decreasing the area (effective area) where the two electrodes overlap. It is a capacitor. For example, one of the two electrodes included in the trimmer capacitor 52 is a fixed electrode that is fixed, and the other is a movable electrode that is movable. The movable electrode is provided with an adjustment member that moves the movable electrode. By adjusting the adjustment member, the movable electrode is moved to increase or decrease the effective area.

  The trimmer capacitor 52 and the coil 51 form a resonance circuit, and the antenna 5 transmits radio waves at the resonance frequency of the resonance circuit. This resonance frequency is determined by the inductance L of the coil 51 and the capacitance C of the trimmer capacitor 52 that forms a resonance circuit with the coil 51. The relationship between the resonance frequency fc of the resonance circuit, the inductance L of the coil 51, and the capacitance C of the trimmer capacitor 52 is shown in the following equation (1).

  The inductance L of the coil 51 and the capacitance C of the trimmer capacitor 52 are attached to the casing of the information terminal device 1 in a state where the resonance frequency fc is set to a desired frequency in consideration of the parasitic capacitance generated in the antenna 5.

  In the present embodiment, the resonance circuit is formed by a trimmer capacitor 52 that can increase or decrease the capacitance C. For this reason, the resonance frequency fc can be changed by increasing or decreasing the capacitance C of the trimmer capacitor 52. In the present embodiment, even if the resonance frequency fc fluctuates after the casing of the information terminal device 1 including the antenna 5 is closed, the capacitance of the trimmer capacitor 52 is adjusted from the outside of the casing by using an adjustment method described later. By increasing or decreasing C, the resonance frequency fc is matched with a desired frequency.

  Next, a specific configuration of the information terminal device 1 will be described. FIG. 3 is an exploded perspective view showing the overall configuration of the information terminal device 1 according to the present embodiment. The information terminal device 1 according to the present embodiment is configured by combining the members shown in FIG.

  In the information terminal device 1 according to the present embodiment, a housing is formed by an upper housing 11, a lower housing 12, and a gasket member 13. The gasket member 13 is formed in an annular shape using an elastic member. When the upper housing 11 and the lower housing 12 are engaged with each other, the gasket member 13 is inserted into a groove provided in each engaging portion and elastically deformed. A gap generated between the upper housing 11 and the lower housing 12 is filled. As shown in FIG. 3, the gasket member 13 has a structure including an opening 15 corresponding to the hole 14 formed in the lower housing 12, and is provided between an operation switch 22 and a hole 14 described later. The gaps that occur are also filled.

  The upper housing 11 has a structure in which a display window 81 for displaying an image is formed and a plurality of buttons 21 for inputting identification information and the like are provided. The display window 81 functions as the display unit 8 in combination with a liquid crystal module 82 described later, and the button 21 functions as the input unit 2 in conjunction with the input switch 25 described later.

  The lower housing 12 has a battery accommodating portion 16, an imaging window 71, and an illumination window 76 formed at the bottom, and the aforementioned hole portion 14 formed at a side surface portion. A loop-shaped coil 51 and a trimmer capacitor 52 constituting the antenna 5 are disposed on the bottom of the lower housing 12.

  The battery accommodating portion 16 is for accommodating a battery 17 that supplies driving power for each component of the information terminal device 1, and is a recessed space provided in the lower housing 12. The lid 18 is fitted into the opening of the battery housing 16, and the lid 18 is fitted into the opening in a state in which the battery 17 is housed to close the battery housing 16 and externally connect the battery 17. It has a function to protect from.

  Further, an adjustment hole 53 is provided on a side surface of the battery housing portion 16 and in a portion close to the trimmer capacitor 52. No other members are attached from the adjustment hole 53 to the trimmer capacitor 52, and a certain space is provided. As will be described later, the capacity C of the trimmer capacitor 52 is increased or decreased by adjusting the adjusting member of the trimmer capacitor 52 through the adjustment hole 53. The adjustment hole 53 is provided on the side surface of the battery housing portion 16 and is closed by the lid portion 18 after the battery 17 is housed in the battery housing portion 16. For this reason, the adjustment hole 53 is not exposed to the outside after the information terminal device 1 is assembled. In addition, the cover part 18 can waterproof the battery accommodating part 16 by providing a waterproof mechanism.

  The imaging window 71 is for fitting the imaging unit 72. The imaging unit 72 includes an optical system 73 including an optical lens, a CCD circuit 74 that photoelectrically converts input light imaged by the optical system 73, and an image processing circuit that processes data output from the CCD circuit 74. 75 for configuring the optical information reading unit 7. The illumination window 76 is for fitting the illumination unit 77. The illumination unit 77 incorporates a light emitting element such as an LED (Light Emitting Diode) and has a function of illuminating the optical information recording medium during an imaging operation by the imaging unit 72.

  The hole 14 is for fitting the operation switch 22. The operation switch 22 is for switching the operation mode of the information terminal device 1 between the information reading process or the information writing process for the RFID tag and the optical information reading process. Corresponding to the number of times the operator presses the operation switch 22, the changeover switch 24 provided at the bottom of the lower housing 12 is configured to be interlocked.

  A circuit board 61 formed of a printed wiring board or the like is disposed in a housing formed by the upper housing 11, the lower housing 12, and the gasket member 13. On the circuit board 61, the input switch 25 corresponding to the button 21 is disposed, and the liquid crystal module 82 is disposed at a position corresponding to the display window 81. The input unit 2 is configured by the button 21, the input switch 25, and the operation switch 22 and the changeover switch 24 described above. The display unit 8 is formed by the display window 81 and the liquid crystal module 82. An electronic circuit group such as a CPU and a memory is arranged on the circuit board 61, and the control unit 10 and the storage unit 10a are configured by the electronic circuit group. Although not shown, a microphone and a speaker are also connected to the circuit board 61, and the sound input / output unit 9 is formed by the microphone and the speaker and the electronic circuit group. Although not shown, the information terminal device 1 also includes an external communication unit 3 and a storage device 4.

  Next, a method for measuring the resonance frequency and a method for adjusting the resonance frequency fc by changing the capacitance C of the trimmer capacitor 52 will be described. The measurement of the resonance frequency and the adjustment of the capacitance C of the trimmer capacitor 52 are performed after the upper housing 11 and the lower housing 12 in which the respective constituent members are arranged at predetermined positions are engaged via the gasket member 13, and This is performed before attaching the battery 17 to 16.

  Here, as a method for measuring the resonance frequency, for example, there is a method of transmitting a radio wave of a desired frequency from an external device to the information terminal device 1 and measuring the reception intensity of the transmission radio wave in the information terminal device 1. When the reception intensity is maximum, the frequency of the transmitted radio wave substantially coincides with the resonance frequency of the resonance circuit of the information terminal device 1, and the resonance frequency is a desired frequency. In this case, since the fluctuation of the resonance frequency of the information terminal device 1 is not recognized, it is not necessary to adjust the resonance frequency by the trimmer capacitor 52. On the other hand, when the reception intensity is low, the frequency of the transmitted radio wave does not match the resonance frequency of the resonance circuit, and the resonance frequency of the resonance circuit becomes a desired frequency by assembling the casing of the information terminal device 1. It is thought that it is fluctuating. In addition to measuring the reception intensity, a radio wave of a desired frequency may be transmitted from the information terminal device 1 and received by an external device. In this case, the trimmer capacitor 52 is adjusted so that the reception intensity at the external device is maximized.

  If the resonance frequency fc of the resonance circuit formed by the coil 51 and the trimmer capacitor 52 does not coincide with the desired frequency, the capacitance C of the trimmer capacitor 52 is adjusted to set the resonance frequency fc to the desired frequency. And Since the resonance frequency fc is expressed by equation (1), the resonance frequency fc can be changed by increasing or decreasing the capacitance C of the trimmer capacitor 52. FIG. 4 is a diagram for specifically explaining the adjustment performed on the trimmer capacitor 52.

  As shown in FIG. 4, the trimmer capacitor 52 includes a groove 521, and the groove 521 functions as an adjustment member. By rotating the groove 521, the movable electrode of the trimmer capacitor 52 moves, the effective area of the trimmer capacitor 52 increases and decreases, and the capacitance C increases and decreases. In order to adjust the capacitance C of the trimmer capacitor 52, a tool 54 whose tip is fitted in the groove 521 is used as shown in FIG. First, the tool 54 is inserted from the adjustment hole 53. Here, from the adjustment hole 53 to the groove 521 of the trimmer capacitor 52, no other member is attached and a certain space is provided. For this reason, the tip of the tool 52 reaches the groove 521 smoothly. Then, the tip of the tool 54 is fitted into the groove 521 of the trimmer capacitor 52 and positioned. The groove 521 is rotated by rotating the tool 54 whose tip is fitted in the groove 521, and the capacitance C of the trimmer capacitor 52 is increased or decreased. Thereafter, the resonance formed by the trimmer capacitor 52 and the coil 51 by measuring the reception intensity of the radio wave transmitted from the external device at the information terminal apparatus 1 or the reception intensity of the radio wave transmitted from the information terminal apparatus 1 at the external device. The resonant frequency fc of the circuit is measured. The resonance frequency is adjusted by adjusting the capacitance C of the trimmer capacitor 52 through the adjustment hole 53 by the adjustment method described above until the resonance frequency fc of the resonance circuit matches the desired frequency.

  When the resonance frequency of the resonance circuit matches the desired frequency, the tool 54 is removed from the adjustment hole 53. And the battery 17 is accommodated in the battery accommodating part 16, and the opening part of the battery accommodating part 16 is closed by inserting the cover part 18, and the assembly of the information terminal device 1 is complete | finished.

  As described above, the fluctuation of the resonance frequency is caused by the coil inductance L and the parasitic capacitance generated in the antenna as a result of the positional relationship between the antenna and the components surrounding the antenna being shifted from the initial set position by assembling the information terminal device. Is caused by fluctuations. Conventionally, after the information terminal device is closed, it has been difficult to adjust the resonance frequency of the resonance circuit formed by the coil and the capacitor to a desired frequency. Processing or information writing processing could not be performed.

  On the other hand, in the present embodiment, after the casing of the information terminal device 1 is closed, the capacitance C of the trimmer capacitor 52 is adjusted from the outside of the casing through the adjustment hole 53. That is, after the casing of the information terminal device 1 is closed and the parasitic capacitance of the antenna 5 and the inductance L of the coil 51 fluctuate, the capacitance C of the trimmer capacitor 52 is increased or decreased by control from the outside of the casing. Then, by increasing / decreasing the capacitance C of the trimmer capacitor 52, the resonance frequency fc of the resonance circuit, that is, the frequency of the radio wave transmitted by the antenna 5 is matched with a desired frequency. For this reason, in the present embodiment, even when the parasitic capacitance of the antenna 5 and the inductance L of the coil 51 change after the housing of the information terminal device 1 is closed, the capacitance C of the trimmer capacitor 52 is increased or decreased from the outside. By doing this, the resonance frequency fc can be matched with a desired frequency for each information terminal device 1. As a result, the information terminal device 1 can stably supply power to the RFID tag, and can accurately perform information reading processing or information writing processing on the RFID tag. Further, the increase / decrease in the capacitance C of the trimmer capacitor 52 can be easily adjusted by the method described above in the assembly process of the information terminal device 1.

  Conventionally, after the information terminal device is assembled, the resonance frequency is measured and inspected for each information terminal device, and the information terminal device whose inspection result is out of the shipable range has to be discarded. In order to adjust the frequency of the transmission radio wave, it is necessary to adjust the coil or the like forming the resonance circuit of the antenna, but it is difficult to reopen the housing after the information terminal device is assembled. However, in the first embodiment, it is possible to adjust the resonance frequency of the antenna 5 from the outside of the casing without opening the casing even after the casing is closed. For this reason, even if the resonance frequency does not match the desired frequency in the inspection after closing the casing of the information terminal device 1, the resonance frequency can be adjusted and shipped to the market, and the yield can be improved. Can be realized.

  Even if the impedance of the antenna 5 is not matched with the impedance of other transmission lines, control circuits, etc. due to variations in the parasitic capacitance and the inductance L of the coil 51, the variation of the characteristic impedance is induced. By adjusting the capacitance C, fluctuations in the impedance of the antenna 5 can be reduced. As a result, it is possible to correct the mismatch of characteristic impedance between the circuits and the like, and it is possible to prevent the transmission efficiency from deteriorating.

  The adjustment hole 53 is provided on the side surface of the battery accommodating portion 16 inside the information terminal device 1. The battery accommodating portion 16 accommodates the battery 17 after adjusting the trimmer capacitor 52, and the battery accommodating portion. The opening 16 is closed by the lid 18. Therefore, since the trimmer capacitor 52 cannot be contacted from the outside of the information terminal device 1 after the information terminal device 1 is assembled, the information terminal device 1 can be shipped to the market while maintaining the adjusted frequency. .

  In the present embodiment, the adjustment hole 53 is provided in the housing, and the trimmer capacitor 52 is adjusted from the outside of the housing through the adjustment hole 53. For this reason, it is not necessary to add a new component member, and the existing information terminal device can be diverted. When the lid 18 has a waterproof mechanism, the adjustment hole 53 is covered with the lid 18 having the waterproof mechanism after the casing of the information terminal device 1 is closed. It is not necessary to add a new waterproofing member in association with the provision of the waterproof member. That is, it is possible to divert the case of the existing information terminal device 1.

  In the present embodiment, the case where the adjustment hole 53 is provided in the battery housing 16 as shown in FIGS. 3 and 4 has been described. However, as shown in FIG. 5, the housing of the information terminal device 1 is provided. You may provide the adjustment hole 53a in the side surface of the body, for example, the side surface of the lower housing 12. In this case, after the opening of the battery accommodating portion 16 is closed by the lid portion 18, the tool 54 is inserted into the information terminal device 1 from the adjustment hole portion 53 a provided on the side surface of the lower housing 12. The tip of the tool 54 is fitted into the groove 521 of the trimmer capacitor 52 and the groove 521 is rotated to increase or decrease the capacity C of the trimmer capacitor. After the capacitance C of the trimmer capacitor 52 is increased / decreased to make the resonance frequency fc coincide with the desired frequency, as shown in FIG. 6, the seal 55a is affixed to the adjustment hole 53a, and the adjustment hole 53a is attached. Block it. In addition to sealing the adjustment hole 53 using the seal 55a, as shown in FIG. 7, the adjustment member 53b is fitted into the adjustment hole 53a by fitting a sealing member 55b corresponding to the size of the adjustment hole 53a. The hole 53a may be closed. Further, the seal 55a and the sealing member 55b may be waterproof members.

  In the present embodiment, the antenna 5 including the trimmer capacitor 52 that functions as a frequency adjusting unit has been described. However, the present invention is not limited thereto, and as illustrated in FIG. 8, a variable coil 57 that functions as a frequency adjusting unit is included. Another antenna 56 may be used. The variable coil 57 is a coil that can increase or decrease the inductance L. The variable coil 57 forms a resonance circuit with the capacitor 59. The resonance frequency fc of the resonance circuit is determined by the inductance L of the coil and the capacitance C of the capacitor as shown in the equation (1). Can be changed. The inductance L of the variable coil 57 is increased or decreased by adjusting the adjustment member to change the effective length of the conductor portion constituting the variable coil 57 or the effective permeability of the magnetic core member.

  Next, a method for adjusting the inductance L of the variable coil 57 will be described. FIG. 9 is a diagram specifically explaining the adjustment performed on the variable coil. As shown in FIG. 9, after closing the casing of the information terminal device 1, the tool 54 is inserted from the adjustment hole 53 provided in the battery housing 16. Here, the groove portion 571 of the variable coil 57 functions as an adjustment member of the variable coil 57, and the inductance L of the variable coil 57 increases or decreases as the groove portion 571 rotates. The tip of the tool 54 inserted from the adjustment hole 53 is fitted into the groove 571, and the groove 571 is rotated by rotating the tool 54 to increase or decrease the inductance L of the variable coil 57. After the resonance frequency fc is matched with a desired frequency by increasing / decreasing the inductance L of the variable coil 57, the battery 17 is accommodated in the battery accommodating portion 16, and the opening portion of the battery accommodating portion 16 is closed with the lid portion 18. The adjustment hole 53 into which the tool 54 is inserted may be provided on the side surface of the casing of the information terminal device 1 as shown in FIG. In this case, as shown in FIGS. 6 and 7, after adjusting the resonance frequency, it is necessary to seal the adjustment hole 53a with the seal 55a, the sealing member 55b, or the like.

  Although the case where the frequency adjusting means is a coil or a capacitor that forms a resonance circuit of the antennas 5 and 56 has been described, the present invention is not limited to this, and the frequency adjusting means is a variable coil and a trimmer capacitor that form an antenna resonance circuit. May be. In this case, the resonance frequency fc is matched with a desired frequency by adjusting the capacitance C of the trimmer capacitor and the inductance L of the variable coil. In order to adjust the capacitance C of the trimmer capacitor and the inductance L of the variable coil, an adjustment hole 53 or an adjustment hole 53a corresponding to each of the trimmer capacitor and the variable coil is formed in the housing.

  The antennas 5 and 56 may further include a resistor or the like as a matching circuit that matches the impedance of the antenna 5 to a predetermined value. The resistance of the antennas 5 and 56 is determined in consideration of the inductance L of the coil 51 and the variable coil 57, the capacitance C of the trimmer capacitor 52 and the capacitor 59, and the parasitic capacitance generated in the antennas 5 and 56.

  In the present embodiment, the information terminal device in which the optical information reading unit for reading the information on the optical information medium is described. However, the present invention is not limited to this, and the information communication device with an external information medium has a predetermined frequency. You may apply to the information terminal device provided only with the RFID function which performs the reading process or the writing process of information using an electromagnetic wave. Further, the present invention is not limited to an information terminal device having an RFID function, and may be applied to an information terminal device that performs radio communication with an information medium or another communication device using radio waves of a predetermined frequency.

It is a block diagram which shows schematic structure of the information terminal device concerning embodiment. It is a block diagram which shows the structure of the antenna in embodiment. It is a disassembled perspective view which shows the specific structure of the information terminal device concerning embodiment. It is a figure explaining the adjustment performed with respect to a trimmer capacitor concretely. It is a figure explaining the adjustment performed with respect to a trimmer capacitor concretely. It is a figure which illustrates concretely the assembly of the information terminal device concerning an embodiment. It is a figure which illustrates concretely the assembly of the information terminal device concerning an embodiment. It is a block diagram which shows the other example of a structure of the antenna in embodiment. FIG. 9 is a diagram specifically illustrating adjustment performed on the variable coil shown in FIG. 8.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Information terminal device 2 Input part 3 External communication part 4 Storage device 5 Antenna 6 RFID processing part 7 Optical information reading part 8 Display part 9 Audio | voice input / output part 10 Control part 10a Memory | storage part 11 Upper housing 12 Lower housing 13 Gasket member 14 Hole Part 15 Opening part 16 Battery housing part 17 Battery 18 Lid part 21 Button 22 Operation switch 24 Changeover switch 25 Coil switch 51 Coil 52 Trimmer capacitor 53, 53a Adjustment hole part 54 Tool 55a Seal 55b Sealing member 56 Antenna 57 Variable coil 58 Terminal portion 59 Capacitor 61 Circuit board 71 Imaging window 72 Imaging unit 73 Optical system 74 CCD circuit 75 Image processing circuit 76 Illumination window 77 Illumination unit 81 Display window 82 Liquid crystal module 521, 571 Groove

Claims (9)

In an information terminal device that includes an antenna for transmitting and receiving a predetermined radio wave and performs an information reading process or an information writing process in a non-contact manner with respect to an external information medium
An information terminal device characterized in that frequency adjustment means for adjusting the resonance frequency of the antenna is provided inside the casing, and an adjustment space from a hole provided in the casing to the frequency adjustment means is provided. .   2. The information terminal device according to claim 1, wherein the frequency adjusting means is a variable capacitor that forms a resonance circuit of the antenna.   The information terminal apparatus according to claim 1, wherein the frequency adjusting means is a variable coil that forms a resonance circuit of the antenna.   2. The information terminal device according to claim 1, wherein the frequency adjusting means is a variable coil and a variable capacitor that form a resonance circuit of the antenna. The housing includes a lid portion that closes a recessed space formed in the housing itself,
The information terminal device according to claim 1, wherein the hole is provided on the housing side of the recessed space.   The information terminal device according to claim 1, wherein the hole is sealed with a sealing member after the resonance frequency is adjusted.   The information terminal device according to claim 5, wherein the lid portion includes a waterproof mechanism that waterproofs the recessed space. Control means for performing the information reading process or the information writing process;
Input means for inputting instruction information of the information reading process or the information writing process;
Display means for displaying information read from the information medium by the information reading process or information to be written to the information medium by the information writing process;
With
The control means includes
An RFID processing unit for controlling the driving of the antenna;
A control unit that performs processing control of the information reading process or the information writing process for the RFID processing unit based on the instruction information input from the input unit;
The information terminal device according to any one of claims 1 to 7, further comprising: Optical information reading means for optically reading information of the information medium,
The input means inputs processing instruction information for optically reading the information by the optical information reading means,
9. The information terminal device according to claim 8, wherein the control unit controls the optical information reading unit to perform processing control of the optically reading processing unit.

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