JP2006211551A - Mobile terminal - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mobile terminal such as a mobile phone incorporated with an IC card function section the communication performance of which can simply be enhanced. <P>SOLUTION: The mobile terminal is configured such that first and second antennas 11, 12 for short distance wireless communication are arranged on a front side and a rear side of a case, the first antenna 11 or the second antenna 12 is selected and connected to a short distance wireless communication means 19 depending on a state of the case discriminated by discrimination means 21 to 27, and the selected antenna is used to carry out the short distance wireless communication with a reader/writer. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a portable telephone terminal such as a wireless telephone terminal having a built-in short-range wireless communication function called a non-contact type IC card.

  In recent years, the use of non-contact type IC cards is rapidly spreading as transportation tickets, membership cards, employee cards, cards for payment methods at stores, and the like. Non-contact type IC card performs authentication processing by performing wireless communication with a nearby reader / writer, so it can be used in a wallet, pass case, etc., and is easier to use than a magnetic card. Is good.

  On the other hand, such a non-contact type IC card (or a circuit component having the same function as the IC card) is built in a portable electronic device such as a mobile phone terminal, and these devices are used in the same manner. Proposals have been made to enable authentication and settlement. When an IC card function unit is incorporated in a portable terminal, the IC card function unit is configured by a circuit component such as a semiconductor chip and an antenna connected to the circuit component, and the card shape is obtained. However, in the following description, when referred to as an IC card, unless otherwise specified, it includes portions of various shapes corresponding to the IC card function. In addition, this type of non-contact type IC card is also referred to as RFID (Radio Frequency Identification) or a wireless IC tag. Even when used alone, there are various types such as a label type, a coin type, and a stick type in addition to the card type. In this case, it is referred to as an IC card for convenience.

  FIG. 4 shows a configuration example of a general IC card. One end and the other end of a loop antenna 91 for performing wireless communication with a reader / writer are connected to an RFID block 94 formed of a semiconductor chip, and a tuning capacitor 92 is connected in parallel to the loop antenna 91. Furthermore, a rectifying diode 93 is connected to one end of the loop antenna 91.

  In such a configuration, when performing wireless communication with a reader / writer, the RFID block 94 is operated by electromagnetic induction from the reader / writer. That is, the signal received by the loop antenna 91 is tuned to the carrier wave of a predetermined frequency output from the reader / writer by the tuning capacitor 92, and the RFID block 94 demodulates the tuned signal. Get the received data. Further, the detected carrier wave is modulated by ASK (Amplitude shift keying) modulation or the like in the RFID block 94 to generate a signal to be transmitted to the reader / writer side, and transmitted from the loop antenna 91.

  The circuit shown in FIG. 4 shows only the circuit corresponding to the IC card function unit. When the card is a single IC card, only the circuit shown in FIG. 4 is necessary. If it is built in, a radio telephone function unit is prepared separately.

Patent Document 1 discloses a non-contact type IC card.
JP 2003-323595 A (FIG. 1)

  By the way, when the IC card function unit performs wireless communication with the reader / writer, the IC card function unit is operated by electromagnetic induction from the reader / writer. The reader / writer needs to be as close as possible. Here, when configured as a single IC card, the card body is usually formed into a plate shape with a synthetic resin, and only one loop antenna is arranged on the card body. -Near-field wireless communication with the reader / writer is possible under almost the same conditions regardless of whether the card is close to the writer or the back side of the card is close to the reader / writer.

  On the other hand, when the IC card function unit is built in the mobile phone terminal, parts and substrates for performing various processes are built in the terminal, and a metal plate for shielding is also arranged. It is difficult to perform wireless communication with the reader / writer on both sides of the terminal with a configuration having only one loop antenna. That is, for example, in the current product, when a loop antenna is built in the back side of the casing constituting the terminal and the back side is brought close to the reader / writer, wireless communication can be performed satisfactorily. When the front side is brought close to a reader / writer, the wireless communication performance is greatly deteriorated.

  In order to avoid this problem, for example, it is conceivable to arrange loop antennas on both the front and back surfaces of the casing constituting the terminal. However, the two antennas are simply connected to the RFID block shown in FIG. 94, there is a problem that the reception sensitivity is lowered, and in the case of diversity reception that simultaneously receives signals from two antennas, a complex system having two reception systems as RFID blocks is provided. There is a problem with the configuration, and a general-purpose RFID chip cannot be used.

  The present invention has been made in view of this point, and an object of the present invention is to improve communication performance with a simple configuration when an IC card function unit is built in a terminal device.

  According to the present invention, first and second antennas for short-range wireless communication are arranged on the front surface side and the back surface side of the housing, and the first antenna or the second antenna is selected according to the state of the housing determined by the determining means. The second antenna is selected and connected to the short-range wireless communication means, and the selected antenna is configured to perform short-range wireless communication with the reader / writer.

  By doing so, only the antennas that are likely to communicate with the reader / writer among the two antennas arranged on the front and back sides of the housing are connected to the short-range wireless communication means. Short-range wireless communication is performed using the selected antenna.

  According to the present invention, of the two antennas arranged on the front surface side and the back surface side of the housing, only the antenna that is likely to communicate with the reader / writer is connected to the short-range wireless communication means. Since short-range wireless communication is performed using the selected antenna, short-range wireless communication can be performed satisfactorily even when either the front side or the back side is brought close to the reader / writer.

  In this case, the determination unit compares the reception strengths of the first and second antennas, determines that the higher reception strength is the side closer to the reader / writer, and causes the selection unit to select, The antenna placed on the surface close to the reader / writer will be connected with strong reception of electromagnetic waves from the reader / writer, and only the antenna that can communicate well with the reader / writer will be automatically connected. become.

  In addition, by selecting the antenna located on the surface where it was determined that the housing was facing downward by detecting acceleration, the surface that was approached by facing the reader / writer facing upward was automatically selected. Connected and can communicate well.

  Furthermore, by combining the process of selecting the antenna disposed on the surface determined that the housing is directed downward from the detection of the acceleration and the process of selecting the antenna in which the reception intensity of a predetermined level or more is detected, An antenna is optimally selected in various cases, and communication can be performed satisfactorily.

  Hereinafter, a first embodiment of the present invention will be described with reference to FIGS.

  In this example, a non-contact type IC card function is incorporated in a mobile phone terminal device. The configuration shown in FIG. 1 will be described. First and second loop antennas 11 and 12 for performing short-range wireless communication with a reader / writer are provided and arranged in a casing constituting a mobile phone terminal device. . The frequency for performing short-range wireless communication with the reader / writer is, for example, 13.56 MHz.

  An example of the arrangement of the two loop antennas 11 and 12 will be described with reference to FIG. 2. Here, for example, a first casing 1 a and a second casing 1 b are used as a casing 1 constituting a mobile phone terminal main body. It is assumed that the hinge portion can be folded. At this time, the first loop antenna 11 is disposed near the front surface (upper side) of the first housing 1a, and the second loop antenna 12 is disposed near the back surface (lower side) of the second housing 1b. Further, an acceleration sensor 21 described later is disposed in one of the cases.

  Returning to FIG. 1, a circuit connected to each of the loop antennas 11 and 12 will be described. A tuning capacitor 13 is connected to one end and the other end of the first loop antenna 11, and the second loop antenna 11 and 12 are connected to each other. A tuning capacitor 14 is connected to one end and the other end of the antenna 12, and a rectifying diode 17 is connected to the other end of the first loop antenna 11. A rectifying diode 18 is connected to the end. The first loop antenna 11 and the second loop antenna 12 are configured to be selectively connected to the RFID circuit block 19 via the changeover switches 15 and 16. Selection of the antenna connected to the RFID circuit block 19 by the changeover switches 15 and 16 is performed under the control of the control unit 23, and control is performed to connect only one of the loop antennas to the RFID circuit block 19. Only one rectifier diode 17 and 18 may be connected between the RFID circuit block 19 and the switch 16.

  In the RFID circuit block 19, reception processing and transmission processing are performed using the connected loop antenna 11 or 12. In other words, it performs a process of demodulating the received data transmitted by ASK modulation with a 212 kHz subcarrier from the reader / writer and transmits it to the reader / writer while receiving electromagnetic waves from the reader / writer. Data to be transmitted is processed by ASK modulation or the like. An RFID circuit block 19 is also provided for an MPU (Micro Processing Unit) system, a clock extraction circuit, a nonvolatile memory, and the like that realize an upper layer of a wireless communication protocol with a reader / writer. The RFID circuit block 19 is composed of, for example, an integrated circuit, data necessary for functioning as an RFID is stored in a memory, and a unique ID is also registered.

  Next, the configuration in which the control unit 23 selects the two loop antennas 11 and 12 will be described. In this example, the acceleration sensor 21 is built in the casing constituting the mobile phone terminal main body, It is configured to be able to detect which surface is facing upward. That is, as shown in FIG. 2, the acceleration sensor 21 is built in the casing 1, and the first casing 1a faces upward from the gravitational acceleration detected by the acceleration sensor 21 (shown in FIG. 2). State) or a state in which the second housing 1b faces upward (a state opposite to the state shown in FIG. 2).

  Specifically, as shown in FIG. 1, the output of the acceleration sensor 21 is sampled by an analog / digital converter 22, and the sampled acceleration data is supplied to the control unit 23. The control unit 23 compares the stored data as the comparison table stored in the memory 24 with the acceleration data to determine which surface is the lower side. Then, the connection of the changeover switches 15 and 16 is controlled so that the loop antenna 11 or 12 arranged on the surface determined to be the lower side by the determination is connected to the RFID circuit block 19. The control unit 23 that performs such control may be incorporated in an integrated circuit that constitutes the RFID circuit block 19.

  Note that the control unit 23 monitors the communication status of the RFID circuit block 19 with the reader / writer. When the RFID circuit block 19 is communicating with the reader / writer, the changeover switch is used regardless of the output state of the acceleration sensor 21. The antenna switching at 15 and 16 may be prohibited to prevent the occurrence of a communication error due to the switching during the communication. In addition, antenna switching is not performed simply by detecting the gravitational acceleration corresponding to the orientation of the housing, but a certain time constant is given to the switching to prevent frequent switching in a short cycle. May be.

  Next, the configuration of the telephone terminal will be briefly described. The RFID circuit block 19 is configured to be able to transfer data with the radio telephone circuit block 31. The radio telephone circuit block 31 is connected to an antenna 32 for radio telephone communication, and performs radio telephone communication for transmission of calls, mail data, etc., access to the Internet, and the like. Display as a telephone is performed on the display unit 33, and operations such as outgoing and incoming calls can be performed with the operation unit 34. You may make it display regarding the communication state (authentication state, charge state, etc.) in the RFID circuit block 34 on the display unit 33.

  The RFID circuit block 19 may use a power source that accumulates electromagnetic waves from the reader / writer and is rectified by the diodes 17 and 18 as an operating power source. It may be operated with. However, regarding the configuration from the acceleration sensor 21 to the control unit 23, it is preferable that the antenna is always operated by the power supplied from the power circuit on the radio telephone side so that the optimum antenna switching is always performed.

  According to the mobile phone terminal device of the present example configured as described above, the housing constituting the terminal device is used when performing wireless communication with the reader / writer using the contactless IC card function built in the terminal device. Wireless communication with the reader / writer can be satisfactorily performed with the body facing up. That is, for example, as shown in FIG. 2, when performing short-distance wireless communication close to a reader / writer 2 installed near a ticket gate of a station or a store cash register, it is installed facing upward. The mobile phone terminal device 1 is brought close to the contact portion 2a to perform communication. When the housing 1b is directed downward as shown in FIG. 2, the direction is detected and the second loop antenna is detected. 12 is connected to the RFID circuit block 19 to perform wireless communication, wireless communication is performed with the contact portion 2a of the reader / writer 2 and the loop antenna 12 facing each other, and wireless communication can be performed satisfactorily.

  Further, when the housing 1a is directed downward, which is the state opposite to the state shown in FIG. 2, the direction is detected, and the first loop antenna 11 is connected to the RFID circuit block 19 for wireless communication. Wireless communication is performed in a state where the contact portion 2a of the reader / writer 2 and the loop antenna 11 face each other, and wireless communication can be performed satisfactorily.

  Next, a second embodiment of the present invention will be described with reference to FIG. This embodiment is also an example in which a non-contact type IC card function is incorporated in a mobile phone terminal device, and the same members as those in FIG. 1 described in the first embodiment are denoted by the same reference numerals. It is. Here, the frequency for performing short-range wireless communication with the reader / writer is 13.56 MHz, as in the first embodiment.

  FIG. 3 is a diagram showing a configuration in the present embodiment. Also in this example, the first and second loop antennas 11 and 12 for performing short-distance wireless communication with the reader / writer are provided and arranged in a casing constituting the mobile phone terminal device. As an arrangement example of the two loop antennas 11 and 12, for example, as shown in FIG. 2 described above, the first loop antenna 11 is arranged near the surface (upper side) of the first housing 1a, and the second The loop antenna 12 is arranged near the back surface (lower side) of the second housing 1b.

  The circuits connected to the loop antennas 11 and 12 are also the same as those described in the first embodiment. That is, a tuning capacitor 13 is connected to one end and the other end of the first loop antenna 11, and a tuning capacitor 14 is connected to one end and the other end of the second loop antenna 12. In addition, a rectifying diode 17 is connected to the other end of the first loop antenna 11, and a rectifying diode 18 is connected to the other end of the second loop antenna 12. The first loop antenna 11 and the second loop antenna 12 are configured to be selectively connected to the RFID circuit block 19 via the changeover switches 15 and 16. Selection of the antenna connected to the RFID circuit block 19 by the changeover switches 15 and 16 is performed under the control of the control unit 23 ′, and control is performed to connect only one of the loop antennas to the RFID circuit block 19. In the RFID circuit block 19, reception processing and transmission processing are performed using the connected loop antenna 11 or 12.

  In this example, the configuration in which the control unit 23 'selects the two loop antennas 11 and 12 is different from that of the first embodiment. Hereinafter, the configuration for selecting the antenna by the control unit 23 ′ will be described. In this example, the acceleration sensor 21 is built in the casing constituting the mobile phone terminal main body, and any surface of the casing faces upward. It is configured to detect whether it is suitable. That is, the output of the acceleration sensor 21 is sampled by the analog / digital converter 22 and the sampled acceleration data is supplied to the control unit 23 '. The control unit 23 ′ compares the stored data as the comparison table stored in the memory 24 with the acceleration data, and determines which surface is the lower side.

  In addition to the configuration for determining acceleration, a configuration for detecting which of the received strengths of the two loop antennas 11 and 12 is stronger is provided. That is, the received signal obtained at one end of each of the loop antennas 11 and 12 is supplied to different peak hold circuits 25 and 26, respectively. In the peak hold circuits 25 and 26, when a 13.56 MHz carrier wave from the reader / writer is received by the antenna 11 or 12, the received intensity is peak-held with a certain time constant. The peak values held by the respective peak hold circuits 25 and 26 are compared with the comparator 27, and control is performed on data indicating which antenna side has a strong reception strength when there is a certain level of reception strength. To the unit 23 '.

  In the control unit 23 ′, the antenna to be selected is determined by the change-over switches 15 and 16 by comprehensively judging the data relating to the received intensity and the data of the casing direction detected by the acceleration sensor 21. For example, when no carrier wave signal is received from the reader / writer from any of the antennas 11 and 12, the antenna facing the lower side of the housing is connected to the RFID circuit block 19 based on the output of the acceleration sensor 21. And wait. When a certain level of reception intensity is detected from both antennas 11 and 12 in such a switched state, the antenna having the higher reception intensity of antennas 11 and 12 according to the reception intensity at that time. Switch to. However, when there is not so much difference in received intensity between the two antennas 11 and 12 (when the difference is less than a predetermined level set in advance), the antenna connected to the lower side of the casing is connected. It may be maintained. In addition, after the wireless communication with the reader / writer is started in a state where any one of the antennas 11 and 12 is connected, the current communication is maintained until the communication is completed. It is also possible to prevent a communication error from occurring due to the switching.

  As described above, the antenna to be used for communication is switched according to the orientation of the housing constituting the mobile terminal device body and the reception levels of both antennas 11 and 12, so that the antenna can be selected satisfactorily. Yes. That is, most of the reader / writers that communicate with the IC card function built in the portable terminal device of this example are such that the contact portion 2a with the IC card faces upward as shown in FIG. Yes, it is always in a standby state in a state where it can communicate with most of the reader / writers satisfactorily, and when it approaches the reader / writer in this state, wireless communication with the reader / writer can be started quickly. For some readers / writers, the contact part with the IC card may be installed in a nearly vertical state. In such a positional relationship, the antenna facing the upper side of the housing Although there is a possibility that the communication can be performed better, in this example, since switching is performed based on the reception intensity, such a case can be dealt with.

  In the second embodiment, the two antennas 11 and 12 are selected by combining the detection of the housing direction by the acceleration sensor 21 and the detection of the stronger reception level by the comparator 27. Although the configuration is such that only the stronger reception level is detected by the peak hold circuits 25, 26 and the comparator 27, the antenna with the stronger reception level is always selected, and then the reception level is stronger than a predetermined level. Until that time, as a configuration for maintaining the connection, the configuration in which the orientation of the housing is detected by the acceleration sensor 21 may not be provided.

  Further, in the first and second embodiments, the direction of the housing is detected by detecting the gravitational acceleration by the acceleration sensor, and the two antennas are switched. It is good also as a structure which detects the direction of a housing | casing and connects the antenna arrange | positioned on the lower surface.

  In addition, although an example in which a loop antenna is used as an antenna for performing wireless communication with a reader / writer has been described, an antenna having another configuration may be used. For example, a chip antenna disposed on a circuit board may be used. In addition, the antennas arranged at two locations on the front and back sides of the casing constituting the terminal device are switched. However, three or more antennas are arranged on different planes of the casing, and sensors are used. You may make it connect the antenna arrange | positioned at the surface detected by the lower side. For example, in addition to the upper and lower surfaces of the housing shown in FIG. 2, loop antennas are also installed on the side surfaces, and when it is determined that the side surfaces face downward, the antennas on the side surfaces are connected. It may be.

  The present invention can also be applied to a case where a function of an IC card or an IC tag is incorporated in a mobile terminal device other than the mobile phone terminal device (for example, a portable information processing terminal such as PDA: Personal Digital Assistance).

It is a block diagram which shows the example by the 1st Embodiment of this invention. It is a perspective view which shows the example of antenna arrangement | positioning by the 1st Embodiment of this invention. It is a block diagram which shows the example by the 2nd Embodiment of this invention. It is a block diagram which shows the example of the conventional IC card.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Housing | casing, 1a ... 1st housing | casing, 1b ... 2nd housing | casing, 2 ... Reader / writer, 11 ... 1st loop antenna, 12 ... 2nd loop antenna, 13, 14 ... Capacitor for tuning, 15, 16 Reference switch, 17, 18 Rectifier diode, 19 RFID circuit block, 21 Acceleration sensor, 22 Analog / digital converter, 23, 23 'Control unit, 24 Memory, 25, 26 Peak hold circuit, 27: Comparator, 31: Circuit block for wireless telephone, 32 ... Antenna, 33 ... Display unit, 34 ... Operation unit

Claims (4)

In a portable terminal device including a short-range wireless communication function unit that detects a carrier wave of a predetermined frequency output from the reader / writer in the housing and performs short-range wireless communication with the reader / writer.
The first and second antennas for short-range wireless communication disposed on the front side and the back side of the housing;
Determining means for determining the state of the housing;
Selection means for selecting the first antenna or the second antenna according to the state of the casing determined by the determination means;
A portable terminal device comprising: a short-distance wireless communication unit that is connected to the antenna selected by the selection unit and performs short-distance wireless communication. The mobile terminal device according to claim 1,
The discrimination means compares the reception strengths of the first and second antennas, discriminates the higher reception strength as being closer to the reader / writer, and causes the selection means to select. A portable terminal device. The mobile terminal device according to claim 1,
The determination means includes an acceleration sensor and a comparison table for comparing with the output of the acceleration sensor,
A portable terminal device that causes the selection means to select an antenna disposed on a surface where the casing is determined to face downward from detection of acceleration. The mobile terminal device according to claim 1,
The discrimination means includes an acceleration sensor, a comparison table for comparing with the output of the acceleration sensor, and comparison means for comparing the reception strengths of the first and second antennas.
While the selection means selects an antenna disposed on the surface where it is determined that the casing is directed downward from the detection of acceleration, the selection is made for the antenna for which the reception intensity of a predetermined level or more is detected by the comparison means. A portable terminal device that is selected by means.

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