Abstract:
The present invention realizes a small thickness and a low price while maintaining the sensitivity of an RFID antenna when setting a non-contact IC card function in a cellular phone. An RFID antenna is mounted on a battery pack of a cellular phone. In this case, by maintaining a predetermined clearance (1 to 2 mm) between the antenna and a battery cell, bad influence of a metallic plate of the battery cell is eliminated. Moreover, in the case of electrical connection with an RFID-function circuit portion, it is unnecessary to prepare a special connector by using a battery connection connector.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The present invention relates to a cellular phone, a battery pack used for the cellular phone, and a connection connector, particularly to a cellular phone including a non-contact IC card function, a battery pack used for the cellular phone, and a connection connector.  
         [0003]     2. Description of Related Art  
         [0004]     In the field of IC cards, a non-contact IC card is rapidly spread and application of the card to various fields is widened like an IC card for automatic examination of tickets in means of transportation because of convenience of non-contact communication with no battery. Because this type of the non-contact IC card transmits and receives data in accordance with a non-contact communication system, it is not necessary to insert a card into a card reader/writer. Therefore, a technique for using a cellular phone by mounting the non-contact IC card function (RFID function: Radio Frequency Identification function) is also proposed (refer to Patent Documents 1 and 2).  
         [0005]     [Patent Document 1] Japanese Patent Laid-Open No. 2002-218031.  
         [0006]     [Patent Document 2] Japanese Patent Laid-Open No. 2003-37861.  
       SUMMARY OF THE INVENTION  
       [0007]     How to set a RFID antenna becomes a problem when mounting the above-mentioned RFID function on a cellular phone. The RFID antenna is a loop antenna. According to the characteristic of the loop antenna, the antenna sensitivity is further improved as the antenna opening becomes larger and the communication distance is increased. Moreover, when a metal is put nearby the antenna, the antenna sensitivity is extremely deteriorated even if the opening is large and a problem occurs that an expected communication distance cannot be obtained. Therefore, in the case of a cellular phone for which decrease in thickness and cost is requested, it is necessary to decrease the cellular phone in thickness and cost while securing the RFID antenna characteristic.  
         [0008]     When referring to Patent Document 1, the technique for setting the RFID function (both RFID antenna and IC card) in the body of a cellular phone is only disclosed but a configuration for decreasing the cellular phone in thickness and cost while securing the above RFID antenna characteristic is not disclosed.  
         [0009]     Moreover, when referring to Patent Document 2, a structure is disclosed in which the whole RFID function is set in the cover of the battery portion of a cellular phone. In the case of this structure, an RFID antenna is also set in the cover of the battery portion. As the setting method, a technique is shown in which an RFID antenna is embedded in the molded portion of the cover and resin-sealed. In the case of this technique, the manufacturing processes of the cover of the battery portion is increased, the manufacturing cost is increased, and the wall thickness of the cover is also increased.  
         [0010]     Therefore it is an object of the present invention to provide a cellular phone without spoiling a small thickness and low cost while keeping the antenna characteristic, a battery pack used for the cellular phone, and a connector.  
         [0011]     A cellular phone of the present invention has a feature of including a non-contact IC card function and a battery pack having a built-in antenna for the non-contact IC card function. Moreover, the cellular phone has a feature of including a connection connector for the battery pack so as to connect the antenna with an electric circuit portion for the non-contact IC card function via the connection connector.  
         [0012]     Furthermore, the cellular phone has a feature of including the reader/writer function of the non-contact IC card and setting an antenna for the reader/writer function in the battery pack. Furthermore, the cellular phone has a feature of connecting the antenna for the reader/writer function with its electric circuit portion via the connection connector of the battery pack.  
         [0013]     A battery pack of the present invention is a battery pack of a cellular phone having a non-contact IC card function and has a feature in which an antenna for the non-contact IC card is set in the body of the battery pack.  
         [0014]     Another battery pack of the present invention is a battery pack of a cellular phone having a non-contact IC card function and the reader/writer function of a non-contact IC card and has a feature of setting an antenna for the non-contact IC card and an antenna for the reader/writer function in the body of the pack.  
         [0015]     A battery connection connector of the present invention is a battery connection connector of a cellular phone including a non-contact IC card function and a battery pack having an antenna for the non-contact IC card function and has a feature of having a terminal for connecting the antenna with an electric circuit portion for the non-contact IC card function.  
         [0016]     Moreover, the battery connection connector has a feature in which the reader/writer function of a non-contact IC card is provided to the cellular phone, an antenna for the reader/writer function is set in the battery pack, and a terminal for connecting the antenna for the reader/writer function with its electric circuit portion is included.  
         [0017]     Functions of the present invention are described below. An RFID antenna is mounted on the battery pack of a cellular phone. In this case, by keeping a predetermined clearance between the antenna and a battery cell, bad influences by the metallic plate of the battery cell are eliminated. Moreover, for the electrical connection of the battery pack with the circuit portion for an RFID function, it is not necessary to prepare a special connector by using a battery connection connector. Furthermore, by using a configuration of mounting the antenna on the battery pack, it is possible to form a loop antenna having a large opening and the characteristic also becomes preferable.  
         [0018]     According to the present invention, by setting an RFID antenna in a battery cell and connecting the antenna with an RFID-function circuit portion by a battery connection connector, special assembly is unnecessary and it is possible to set the function of a non-contact IC card in a cellular phone with a simple configuration. Thus, there is an advantage that a low price can be maintained.  
         [0019]     Moreover, the influence of the battery pack in the battery cell on the RFID antenna is eliminated by securing a very small (1 to 2 mm) clearance between the battery pack and the antenna. Therefore, there is an advantage that the non-contact IC card function can be built in a cellular phone without spoiling the small thickness of the cellular phone. Furthermore, by forming the antenna on the flat plate portion of the battery pack like a loop, advantages are obtained that the opening becomes large and the antenna characteristic can be also preferably maintained. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0020]      FIGS. 1A and 1B  are illustrations showing an example of a battery back of an embodiment of the present invention, in which  FIG. 1A  is a top view and  FIG. 1B  is a side view;  
         [0021]      FIG. 2  is an illustration showing a relation between distances (clearances) between a metallic plate and an RFID antenna and card-side induced voltages;  
         [0022]      FIG. 3  is an equivalent-function block diagram of an embodiment of the present invention;  
         [0023]      FIGS. 4A and 4B  are illustrations showing the battery connection connector in  FIG. 3 , in which  FIG. 4A  is a top view and  FIG. 4B  is a side view;  
         [0024]      FIGS. 5A and 5B  are illustrations showing an example of the battery pack of another embodiment of the present invention, in which  FIG. 5A  is a top view and  FIG. 5B  is a side view;  
         [0025]      FIGS. 6A and 6B  are illustrations showing an example of the battery connection connector in  FIG. 5 , in which  FIG. 6A  is a top view and  FIG. 6B  is a side view;  
         [0026]      FIG. 7  is a back view of a general cellular phone;  
         [0027]      FIGS. 8A and 8B  are illustrations showing an example of a battery pack used for a general cellular phone, in which  FIG. 8A  is a top view and  FIG. 8B  is a side view;  
         [0028]      FIGS. 9A and 9B  are illustrations showing an example of the battery connection connector in  FIG. 8 , in which  FIG. 9A  is a top view and  FIG. 9B  is a side view;  
         [0029]      FIG. 10  is an equivalent function block diagram of the general cellular phone in  FIG. 7 ;  
         [0030]      FIG. 11  is an equivalent circuit diagram of an RFID-function non-contact IC card and a reader/writer; and  
         [0031]      FIG. 12  is an illustration for explaining operations of the circuit in  FIG. 11 . 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0032]     Embodiments of the present invention are described below by referring to the accompanying drawings. Before describing the embodiments, a general cellular phone and a non-contact IC card having an RFID function are described.  
         [0033]     First,  FIG. 7  is a back view of a general cellular phone, in which a back LCD portion  13  and a battery pack  2  are set to the cellular phone body  1  and the battery pack  2  is removably set to the cellular phone body  1  and therefore, a battery connection connector  4  is set to the cellular phone body  1 .  
         [0034]      FIGS. 8A and 8B  show a structure of the battery pack  2 , in which  FIG. 8A  is a top view and  FIG. 8B  is a side view. A battery cell  21  is built in the body of the battery pack  2  and not only a positive terminal  31  and a negative terminal  33  but also a sens terminal  32  are set to the battery cell  21 . When mounting the battery pack  2  on the cellular phone body  1  shown in  FIG. 7 , these terminals  31  to  33  are connected to the battery connection connector  4 . The sens terminal  32  serves as an output terminal for a temperature sensor.  
         [0035]      FIGS. 9A and 9B  show a structure of the battery connection connector  4 .  FIG. 9A  is a top view of the structure and  FIG. 9B  is a side view of the structure, and a reference numeral  41  denotes a battery cell connection terminal.  
         [0036]      FIG. 10  is an equivalent function block diagram showing a relation between the cellular phone body  1  and the battery pack  2 , in which an equivalent portion as that in FIGS.  7  to  9  is shown by the same symbol. The terminals  31  to  33  of the battery cell  21  are connected to a power supply circuit  11  in the cellular phone body  1  through the battery connection connector  4  to supply power.  
         [0037]      FIG. 11  is an equivalent circuit diagram for explaining the communication principle of a general RFID function. In  FIG. 11 , a R/W (reader/writer) block  6  and a card block  5  are used for a general RFID function. In the R/W block  6 , a 13.56 MHz AC signal generated by an oscillating section  63  is amplified by a transmission amplifier  62  and supplied to a R/W transmission antenna  64  as a current. Because the 13.56 MHz AC current passes through the R/W transmission antenna  64 , a magnetic flux  60  proportional to the current is generated around the antenna.  
         [0038]     Moreover, because the current and magnetic flux passing through the R/W transmission antenna  64  are changed as shown in  FIG. 12  in accordance with the current amplification rate of the transmission amplifier  62  to be switched correspondingly to the control by a modulation section  61 , ASK (Amplitude Shift Keying) modulation is performed.  
         [0039]     In the case of the card block  5 , a modulation signal is received by an RFID antenna  22  for a card being interlinked with the magnetic flux  60  generated by the R/W transmission antenna  64  and supplied to a demodulation section  51  to realize communication. Moreover, a capacitor  54  set in parallel with an antenna  55  constitutes a resonator together with the antenna  22  and is adjusted so that a resonant frequency becomes 13.56 MHz.  
         [0040]     Transmission signal from the card block  5  is received by a demodulation section  65  when a load  53  is switching-controlled through the control by a modulation section  52  to detect a change of magnetic fluxes generated by the R/W transmission antenna  64  being interlocked with an R/W reception antenna  66  in the R/W block  6 .  
         [0041]     When mounting the above card block  5  on a cellular phone, a method for mounting the RFID antenna (antenna for card)  22  for efficiently interlocking the magnetic flux  60  generated by the R/W transmission antenna  64  becomes a problem as described above. For example, when a metallic plate having the same size as the RFID antenna  22  is present on the same face as the antenna, it is hardly possible to induce electric power in the card block  5 .  
         [0042]     Therefore, in the case of the embodiment of the present invention, as shown in  FIGS. 1A and 1B , the influence of the metallic face of the battery cell  21  is eliminated by mounting the RFID antenna  22  on the battery pack  2  and securing necessary clearances a 1  and a 2  in the battery pack  2  between the battery cell  21  which is a metallic body and the RFID antenna  22 .  
         [0043]      FIG. 2  shows a relation between card-side induced voltages and distances between a metallic plate and an RFID antenna. As shown in  FIG. 2 , by separating the RFID antenna  22  from the battery cell  21  by 1 to 2 mm, it is found that sudden improvement of an induced voltage in the antenna  22  can be achieved.  
         [0044]     Thus, to mount an RFID function on a cellular phone, by securing a clearance of 1 to 2 mm between the RFID antenna  22  and the battery cell  21  and setting the antenna  22  in a battery pack, it is possible to mount the RFID antenna keeping the characteristic preferable without spoiling the small thickness and low price of the cellular phone.  
         [0045]     By forming the RFID antenna  22  like a loop on the flat portion of the battery pack  2 , the opening is increased in size and the antenna characteristic is preferably maintained.  
         [0046]     In  FIGS. 1A and 1B ,  FIG. 1A  is a top view and  FIG. 1B  is a side view, in which a structure of securing the above clearances a 1  and a 2  for the battery cell  21 , building the antenna  22  in the battery pack  2 , and setting positive and negative terminals (CP and CN terminals)  34  and  35  on the same face as three terminals  31  to  33  of the battery cell  21  of the battery pack  2  is used.  
         [0047]      FIG. 3  is an equivalent-function block diagram corresponding to the above described  FIG. 10  in the case of an embodiment of the present invention, in which the same portion as those in  FIGS. 1 and 2  and  FIG. 10  is shown by the same symbol. This embodiment uses a configuration in which the terminals  34  and  35  of the RFID antenna  22  are connected with an RFID communication circuit  12  in the cellular phone body  1  through the battery connection connector  4  in addition to the configuration of  FIG. 10 . In this case, the battery connection connector  4  has the structure shown in  FIGS. 4A and 4B . That is, two terminals (card positive terminal CP and card negative terminal CN) shown by reference numeral  42  serve as RFID antenna connection terminals.  
         [0048]      FIGS. 5A and 5B  are a top view ( FIG. 5A ) and a side view ( FIG. 5B ) of the battery pack  2  showing another embodiment of the present invention, in which the same portion as that in  FIG. 1  is shown by the same symbol. In the case of this embodiment, a cellular phone is provided with the reader/writer function of a non-contact IC card in addition to the non-contact IC card function. An RFID antenna  23  for reader/writer is mounted on the battery pack  2  together with the RFID antenna  22  for a card and connection connector terminals  36  and  37  for this are added.  FIGS. 6A and 6B  are a top view ( FIG. 6A ) and a side view ( FIG. 6B ) of the battery connection connector  4  used for this embodiment.  
         [0049]     By providing a reader/writer function for a cellular phone, it is possible to confirm the content of a non-contact IC card. However, when providing a writer function, a problem may occur because data can be freely written in the IC card. In this case, however, it is necessary to provide only a reader function. In short, also when an antenna is added, there is an advantage that correspondence is easily possible.