JP5289908B2 - Communication equipment - Google Patents

Description

  The present invention relates to a communication device that communicates with an external device.

  Currently, there is known a communication device having a communication means for performing magnetic field communication with an external device using the principle of electromagnetic induction. This communication means is configured by, for example, RFID (Radio Frequency Identification) which is a non-contact IC (Integrated Circuit) chip.

  The communication means is configured by a magnetic field antenna or the like, and a resonance (tuning) frequency (frequency at which the external device resonates) for performing magnetic field communication with the external device is determined. This resonance frequency is determined to be within a certain range (spec-in).

  Here, the adjustment operation of the resonance frequency will be described. The resonance frequency is mainly determined by the inductance value of the magnetic field antenna, the resonance capacitor, the terminal capacitance of the RFID IC chip, and the like.

  For example, in a communication device assembly process, a technique has been proposed in which a conductive member is applied to a magnetic field antenna for RFID to change the inductance value of the magnetic field antenna and adjust the resonance frequency (for example, Patent Document 1). See).

In addition, for example, a function for adjusting the resonance frequency using a trimmer capacitor or the like is mounted on the circuit board, and a hole or the like is formed in the housing so that the trimmer capacitor can be adjusted from the outside of the portable terminal device. In the resonance frequency adjustment process before shipment, a technique for adjusting the resonance frequency has been proposed (see, for example, Patent Document 2).
JP 2003-188765 A JP 2005-229474 A

  By the way, strictly speaking, the communication means has different resonance frequencies for performing magnetic field communication with external devices. Therefore, it is necessary to individually adjust the resonance frequency as described above, and there is a problem that a useless adjustment process occurs.

  Therefore, in order to solve the above-described problems, the present invention is to provide a communication device that can suitably adjust the resonance frequency of the communication means without requiring an adjustment process in factory shipment.

In order to solve the above problems, a communication device according to the present invention is configured to perform magnetic field communication with an external device at a predetermined resonance frequency, and the external device connected to the magnetic field antenna unit and performed by the magnetic field antenna unit. A frequency at which the predetermined resonance frequency is changed when a communication voltage generated in association with the magnetic field communication with the device is equal to or higher than a predetermined value, and the predetermined resonance frequency is not changed when the communication voltage is lower than the predetermined value. A change unit, wherein the predetermined value changes according to a type of the external device .

  According to the present invention, the efficiency of the adjustment process can be improved.

  Embodiments of the present invention will be described below.

  FIG. 1 is an external perspective view of a mobile phone device 1 which is an example of a communication device according to the present invention. 1 shows a form of a so-called foldable mobile phone device, the form of the mobile phone device according to the present invention is not particularly limited to this. For example, a sliding type in which one casing is slid in one direction from a state in which both casings are overlapped, or a rotary type in which one casing is rotated around an axis along the overlapping direction ( Turn type), or a type (straight type) in which the operation unit and the display unit are arranged in one housing and does not have a connecting unit.

  The mobile phone device 1 includes an operation unit side body unit 2 and a display unit side body unit 3. The operation unit side body unit 2 includes an operation button group 11 and a voice input unit 12 into which a voice uttered by a user of the mobile phone device 1 is input on the surface unit 10. The operation button group 11 includes a function setting operation button 13 for operating various functions such as various settings, a telephone book function, a mail function, and the like, and an input operation button 14 for inputting a telephone number and characters such as mail. And a determination operation button 15 for performing determination and scrolling in various operations.

  Further, the display unit side body unit 3 is configured to include a display 21 for displaying various types of information on the surface unit 20 and a sound output unit 22 for outputting the voice of the other party of the call.

  Further, the operation button group 11, the voice input unit 12, the display 21, and the voice output unit 22 described above constitute a part of the processing unit 62 described later.

  Further, the upper end of the operation unit side body 2 and the lower end of the display unit side body 3 are connected via a hinge mechanism 4. In addition, the cellular phone device 1 relatively rotates the operation unit side body 2 and the display unit side body 3 connected via the hinge mechanism 4, thereby Relative movement is possible between a state in which the display unit side body 3 is open (open state) and a state in which the operation unit side body 2 and the display unit side body 3 are folded (folded state). Configured.

  FIG. 2 is an exploded perspective view of a part of the operation unit side body 2. As shown in FIG. 2, the operation unit side body unit 2 includes a substrate 40, an RFID unit 41, a rear case unit 42, a rechargeable battery 43, and a rechargeable battery cover 44.

  The substrate 40 is mounted with an element such as a CPU that performs predetermined arithmetic processing, and a predetermined signal is supplied to the CPU when the user operates the operation button group 11 on the surface portion 10.

  The RFID unit 41 includes a magnetic field antenna unit 50 that performs magnetic field communication with an external device using a first frequency band, an RFID chip 51 that performs predetermined processing on information that is magnetically communicated by the magnetic field antenna unit 50, and will be described later And a reactance variable section 52. Note that the RFID chip 51 is disposed on the substrate 40 facing the RFID unit 41 as shown in FIG. Details of the RFID unit 41 will be described later.

  The rear case portion 42 houses a main antenna 70 that communicates with a hinge mechanism fixing portion 42A that fixes the hinge mechanism 4 and a second use frequency band that is a higher frequency band than the first use frequency band. A storage unit 42B, a rechargeable battery storage unit 42C for storing the rechargeable battery 43, and an RFID unit fixing unit 42D for fixing the RFID unit 41 are provided. Details of the main antenna 70 will be described later.

  FIG. 3 is a functional block diagram showing functions of the mobile phone device 1. As shown in FIG. 3, the cellular phone device 1 processes information communicated by the RFID unit 41 (communication means), which is the first communication unit, the second communication unit 61, and the second communication unit 61. And a processing unit 62.

  As described above, the RFID unit 41 includes the magnetic field antenna unit 50 that performs magnetic field communication with an external device in the first use frequency band (for example, 13.56 MHz), the RFID chip 51, and the reactance variable unit 52 (frequency change unit). And).

  The magnetic field antenna unit 50 is, for example, a magnetic field antenna including a coil wound in a plurality of times on a sheet made of a PET (polyethylene terephthalate) material, and a first use frequency band with an external device. Send and receive signals.

  The RFID chip 51 includes a power supply circuit 53 that generates a predetermined power supply voltage, an RF circuit 54 that performs signal processing such as modulation processing or demodulation processing on a signal communicated by the magnetic field antenna unit 50, and predetermined arithmetic processing. A CPU 55 is provided, and a memory 56 in which predetermined data is stored. The power supply circuit 53 is configured by, for example, a DC-DC converter.

  Here, the operation of the RFID unit 41 will be described.

  When the magnetic field antenna unit 50 approaches a predetermined distance from an external reader / writer device (external device), the magnetic field antenna unit 50 transmits an electromagnetic wave (carrier in the first used frequency band). Receives a frequency (eg, modulated by 13.56 MHz). The reactance variable unit 52 performs a predetermined adjustment (tuning) so that the electromagnetic wave in the first use frequency band is supplied to the RF circuit 54 via the magnetic field antenna unit 50.

  The power supply circuit 53 generates a predetermined power supply voltage based on the power supply voltage supplied from the rechargeable battery 43, and supplies it to the RF circuit 54, the CPU 55, and the memory 56. Further, the RF circuit 54, the CPU 55, and the memory 56 shift from the stopped state to the activated state when a predetermined power supply voltage is supplied from the power supply circuit 53.

  The RF circuit 54 performs signal processing such as demodulation on the signal in the first used frequency band supplied via the magnetic field antenna unit 50, and supplies the processed signal to the CPU 55.

  The CPU 55 writes data in the memory 56 or reads data from the memory 56 based on the signal supplied from the RF circuit 54. When the CPU 55 reads data from the memory 56, the CPU 55 supplies the data to the RF circuit 54. The RF circuit 54 performs signal processing such as modulation on the data read from the memory 56 and transmits the modulated signal to the external device via the magnetic field antenna unit 50.

  In the above description, the RFID unit 41 is described as an active type that is driven based on the power supply voltage supplied from the rechargeable battery 43. However, the RFID unit 41 is not limited to this, and the electromotive force is generated by electromagnetic induction. A so-called passive induction electromagnetic field method (electromagnetic induction method), a passive mutual induction method (electromagnetic coupling method), or a radiated electromagnetic field method (radio wave method) may be used. In addition, the access method of the RFID unit 41 has been described as being a read / write type, but is not limited thereto, and may be a read only type, a write once type, or the like.

  Further, as shown in FIG. 3, the second communication unit 61 includes a main antenna 70 that communicates with an external device in a second use frequency band that is a higher frequency band than the first use frequency band, and a modulation process. Or a communication processing unit 71 that performs signal processing such as demodulation processing. Further, the second communication unit 61 is supplied with power from the rechargeable battery 43.

  The main antenna 70 communicates with an external device in the second use frequency band (for example, 800 MHz). In the present embodiment, the second use frequency band is 800 MHz, but other frequency bands may be used. Further, the main antenna 70 may have a so-called dual band compatible type that can support a third use frequency band (for example, 2 GHz) in addition to the second use frequency band. It may be configured by a multi-band compatible type that can also support the used frequency band.

  The communication processing unit 71 demodulates the signal received by the main antenna 70, supplies the processed signal to the processing unit 62, modulates the signal supplied from the processing unit 62, and performs external processing via the main antenna 70. Send to device.

  Further, as shown in FIG. 3, the processing unit 62 includes an operation button group 11, a voice input unit 12, a display 21, a voice output unit 22, and a CPU 72 (1 of communication state monitoring means) that performs predetermined arithmetic processing. A memory 73 in which predetermined data is stored, an acoustic processing unit 74 that performs predetermined sound processing, an image processing unit 75 that performs predetermined image processing, a camera module 76 that captures a subject, and an incoming call And a speaker 77 for outputting sound and the like. Further, the processing unit 62 is supplied with power from the rechargeable battery 43. As shown in FIG. 3, in the mobile phone device 1, the CPU 55 and the CPU 72 are connected by a signal line S, and information processed by the RFID unit 41 via the signal line S is sent to the image processing unit 75. Information supplied and processed by the image processing unit 75 is displayed on the display 21.

Next, the resonance frequency f ₀ (predetermined resonance frequency) of the RFID unit 41 will be described.

As shown in FIG. 4, the resonance frequency f ₀ of the magnetic field antenna unit 50 constituting the RFID unit 41 has a predetermined range (specification pass range) determined in advance so that communication with an external device can be suitably performed. It needs to be adjusted to fit within the range. This is because when the resonance frequency f ₀ is lower than a certain range, the maximum communication distance between the magnetic field antenna unit 50 and the external device is shortened, which is not suitable for actual use. On the other hand, when the resonance frequency f ₀ is higher than a certain range, as shown in FIG. 5, the maximum communication distance becomes long, but communication is performed in a region where the communication distance between the magnetic field antenna unit 50 and the external device is short. There is a problem in that it is not suitable for actual use because an unusable area (area where communication with an external device cannot be performed) occurs.

Therefore, in the present invention, in view of the characteristics of the resonance frequency f ₀ as described above, the reactance is changed by the reactance variable unit 52 according to the communication state, and the resonance frequency f ₀ is changed so that communication with an external device can be performed appropriately. To do. For example, at the time of communication, the type of the external device is determined, the reactance of the reactance variable unit 52 is changed according to the type of the external device, and the resonance frequency f ₀ is adjusted to a value that enables suitable communication.

  FIG. 6 is a circuit diagram for explaining the basic configuration and operation of the main part of the RFID unit 41. The reactance variable unit 52 includes an FET switch unit 52c (switch unit) whose drain side is connected in series to the adjustment capacitor 52b, an adjustment resistor 52a connected to the base side of the FET switch unit 52c, and a drain of the FET switch unit 52c. And a resistor 52d connected to the side. The FET switch unit 52c and the adjustment capacitor 52b are connected in parallel to the magnetic field antenna unit 50, and the power supply voltage Vcc is applied to the drain side of the FET switch unit 52c via the resistor 52d.

  In the circuit shown in FIG. 6, when the resistance value R1 of the adjustment resistor 52a is small, the FET switch section 52c is turned off, the lower end (drain side) of the adjustment capacitor 52b is OPEN, and the adjustment capacitor 52b is It becomes invalid. For this reason, even if a large AC voltage (voltage) greater than or equal to a predetermined value generated when performing magnetic field communication with an external device is applied to the magnetic field antenna unit 50, the FET switch unit 52c is turned off. On the other hand, when the resistance value R1 of the adjustment resistor 52a is large, when a large AC voltage equal to or greater than a predetermined value is applied to the magnetic field antenna unit 50, when the communication distance between the magnetic field antenna unit 50 and the external device is increased, from the drain side The electric charge leaking to the gate side does not flow to the GND, but is accumulated at the gate end and the drain-source state is turned on.

Here, when the FET switch section 52c is turned on, the adjustment capacitor 52b becomes effective. When the adjustment capacitor 52b becomes effective, the capacitance (C) value increases.
f ₀ = 1 / 2π√ (LC) (1)
It is possible to change the resonance frequency f ₀ to a value lower than the predetermined frequency fx.

In other words, by changing the resonance frequency f ₀ to a low value, it is possible to suppress the occurrence of the incommunicable area. On the other hand, by changing the resonance frequency f ₀ to a low value, the maximum communication distance is shortened, thus FET switch portion 52c from turning on is somewhat communication distance between the magnetic field antenna portion 50 and the external device Even if it becomes shorter, the communication between the magnetic field antenna unit 50 and the external device is favorably maintained.

Further, in this case, if a large AC voltage equal to or greater than a predetermined value is not applied to the magnetic field antenna unit 50 (if the communication distance between the magnetic field antenna unit 50 and the external device is long), the drain-source state is maintained. That is, the value of the resonant frequency f _0, (and thus not be changed to a low value) it become to be maintained. As a result, the maximum communication distance between the magnetic field antenna unit 50 and the external device can be increased, and the communication possibility between the magnetic field antenna unit 50 and the external device can be improved. On the other hand, since the value of the resonance frequency f ₀ is maintained, there is a possibility that the communication incompatibility region may occur as compared with the case where the value of the resonance frequency f ₀ is lowered. The state where a large AC voltage of a predetermined value or more is not applied assumes that the communication distance between the magnetic field antenna unit 50 and the external device is long in the first place. There is a low possibility that the communication between the magnetic field antenna unit 50 and the external device is hindered due to the influence of the non-communication area.
Note that the resonance frequency f ₀ can be adjusted by using the inductance (L) instead of the capacitance (C).

  FIG. 7 shows the relationship between the resistance value R1 of the adjusting resistor 52a in the circuit shown in FIG. 6 and the drain end voltage Vd at which the FET switch 52c is turned on. As shown in FIG. 4, even if the voltage (Vd) applied to the magnetic field antenna unit 50 is relatively small, in order to turn on the FET switch unit 52c, the adjustment resistor 52a has a relatively high resistance value (Ra). The above resistance may be selected. Therefore, by changing the resistance value Ra of the adjustment resistor 52a, it is possible to change the value of the voltage that serves as a threshold at which the FET switch section 52c is switched ON / OFF. By appropriately selecting Ra, the FET switch section 52c can be turned on / off at an arbitrary voltage.

<Example 1>
FIG. 8 is a circuit diagram showing a part of the configuration of the RFID section in the first embodiment according to the present invention. The same members as those in the basic configuration shown in FIG. 6 or members having the same functions are denoted by the same reference numerals, and detailed description thereof is omitted. The circuit shown in FIG. 8 is a switch that switches between the case where the adjusting resistor 52a is connected to the base side of the FET switch portion 52c and the case where the adjusting resistor 52a is not connected in the reactance variable portion 52 shown in FIG. 52e is provided. The switch 52e is subjected to switching control by the CPU 55. In the default setting, the switch 52e selects the case where no resistor is connected. In other words, it is set higher resonance frequency f _0.

  Here, the switching control of the switch 52e will be described. First, when the magnetic field antenna unit 50 receives a radio signal from an external device, the RFID unit 41 extracts unique information (for example, a product number) of the external device that is a transmission destination from the received radio signal, and extracts the unique Information data is transmitted to the CPU 72.

Based on the signal transmitted from the RFID unit 41, the CPU 72 refers to a table stored in the memory 73 and determines which of the switches 52e is to be switched. The table shows the correspondence between the unique information and the switching state of the switch 52e. And the command which instruct | indicates whether the switch 52e is switched to the RFID part 41 is transmitted. Then, CPU 55 of the RFID unit 41 switches the switch 52e in accordance with a command from the CPU 72, to adjust the resonance frequency _{f 0.} As described above, after the resonance frequency f ₀ is adjusted, various types of data are transmitted and received between the mobile phone device 1 and the external device. Note that it is desirable to periodically update the table representing the correspondence between the unique information and the switching state of the switch 52e by using the wireless data communication function of the mobile phone device 1.

As described above, according to the first embodiment, it is possible to automatically adjust the resonance frequency f ₀ more suitable for communication according to the type of the external device. In addition, it is possible to adjust the resonance frequency f ₀ with a simple circuit configuration using the reactance variable unit 52 and the FET switch unit 52c and a resistor, and it is possible to reduce the cost by reducing the number of components and the number of components. It becomes possible.

In addition, since the cellular phone device 1 automatically adjusts the resonance frequency f ₀ according to the unique information of the external device, it is not necessary to adjust the resonance frequency f ₀ at the time of shipment. Alternatively, the adjustment can be simplified. As a result, it is possible to reduce the number of steps according to adjust the resonance frequency f _0, and accordingly, cost reduction can be achieved.

In the first embodiment described above, either the case where the adjustment resistor 52a is present or the case where it is absent is selected. However, the present invention is not limited to this, and the base side of the FET switch portion 52c is selected. A plurality of adjustment resistors 52a having different resistance values may be connected to each other, and one of them may be selected by the switch 52e. It goes without saying that the case where the resistance value is 0 [Ω], that is, the case where there is no adjustment resistor 52a may be included in the plurality of different adjustment resistors 52a. This resonance, which allows to shift the stepwise resonance frequency f ₀ depending on the received voltage generated by the detection of the magnetic field of the magnetic field antenna portion 50, corresponding to a plurality of types of external devices, more suitable for communication it is possible to adjust the frequency f _0. Further, by changing the resistance value of the adjustment resistor 52a, it is possible to easily adjust the voltage at which the FET switch unit 52c operates.

<Example 2>
FIG. 9 is a circuit diagram showing a part of the configuration of the RFID section in the second embodiment according to the present invention. The circuit shown in FIG. 9 is obtained by connecting a plurality of reactance varying units 52 shown in FIG. 6 to the magnetic field antenna unit 50 in parallel. Here, the reactance variable units 52 shown in FIG. 6 connected to the magnetic field antenna unit 50 have different resistance values of the adjustment resistors 52a. Note that unlike the first embodiment, the memory 73 does not store a table representing the correspondence between the unique information and the switching state of the switch 52e.

In the circuit shown in FIG. 9, two reactance variable units 52 are connected in parallel to the magnetic field antenna unit 50. In one reactance variable unit 52, the resistance value of the adjustment resistor 52a is R1, and the capacitance of the adjustment capacitor 52b is the capacitance. Let C1. The resistance value of the adjustment resistor 52a in the other reactance variable unit 52 is R2, and the capacitance of the adjustment capacitor 52b is C2. If R1 <R2 is assumed, as the drain terminal voltage Vd increases, the FET switch unit 52c corresponding to R2 is turned ON first, and then the FET switch unit 52c corresponding to R1 is turned ON. . Note that the FET switch unit 52c corresponding to R1 does not turn ON first. Therefore, by switching the ON / OFF of the FET switch portion 52c, the drain terminal voltage Vd1, respectively drain end voltage Vd2 corresponding to R2 C1, C2 min stepwise shifting the resonance frequency _{f 0} of the equivalent to R1 It becomes possible to make it.

Thus, according to the second embodiment, it is possible to adjust to the resonance frequency f ₀ more suitable for communication according to the type of external device. Further, the variable reactance section 52, it is possible to adjust the resonance frequency f ₀ by a simple circuit configuration using the resistors and FET switch portion 52c, to reduce costs due to the low cost and component count small parts Is possible.

In addition, at the time of shipment, there is no need to adjust the f _0. Alternatively, the adjustment can be simplified. As a result, it is possible to reduce the number of steps according to adjust the resonance frequency f _0, and accordingly, cost reduction can be achieved.

In addition, by superposing the circuits of the reactance variable unit 52 in two stages and three stages, it becomes possible to shift the resonance frequency f ₀ stepwise in accordance with the reception voltage generated by the magnetic field detection of the magnetic field antenna unit 50. Therefore, it is possible to adjust the resonance frequency f ₀ to be compatible with a plurality of types of external devices and more suitable for communication. Further, since the resistance value of the adjustment resistor 52a can be selected by an application such as a reader / writer, it is possible to select a voltage that can detect a magnetic wave from an external device without changing the adjustment resistor 52a.

  In the second embodiment described above, two reactance variable sections 52 are connected, but may be three or more. Further, instead of the reactance variable section 52 of the second embodiment, a plurality of reactance variable sections 52 of the first embodiment may be connected in parallel. In this case, as in the first embodiment, the memory 73 stores a table representing the correspondence between the unique information and the switching state of the switch 52e.

It is a perspective view which shows the external appearance of the mobile telephone apparatus which concerns on this invention. It is a perspective view which shows the structure of the operation part side housing | casing part with which the mobile telephone apparatus which concerns on this invention is equipped. It is a block diagram which shows the function of the mobile telephone apparatus which concerns on this invention. It is a figure which shows the specification range of the resonant frequency of the magnetic field antenna part which concerns on this invention. It is a figure which shows the relationship between the communication distance with respect to the resonant frequency of the magnetic field antenna part which concerns on this invention, and a communication impossible area. It is a figure which shows the basic composition of the RFID part which concerns on this invention. It is a figure which shows the relationship between the resistance for adjustment in the circuit of FIG. 6, and the drain end voltage from which FET switch part turns ON. It is a figure which shows the structure of the RFID part which concerns on this invention. It is a figure which shows the structure of the RFID part which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cellular phone apparatus 2 Operation part side housing | casing part 3 Display part side housing | casing part 4 Hinge mechanism 40 Board | substrate 41 RFID part (communication means)
50 Magnetic field antenna section 51 RFID chip 52 Reactance variable section (frequency variable means)
52a Adjustment resistor (changing means)
52b Adjustment capacitor 52c FET switch section (changing means)
52d resistor 52e switch (switching means)
72 CPU (discriminating means)

Claims (1)

A magnetic field antenna unit that performs magnetic field communication with an external device at a predetermined resonance frequency;
When the communication voltage connected to the magnetic field antenna unit and generated by the magnetic field communication with the external device performed by the magnetic field antenna unit is equal to or higher than a predetermined value, the predetermined resonance frequency is changed, and the communication voltage is A frequency changing unit that does not change the predetermined resonance frequency when lower than the predetermined value ,
The predetermined value varies depending on the type of the external device.

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