Abstract:
A communication device includes a proximity wireless communication antenna for contactless proximity wireless communication with a counterpart instrument antenna in proximity, a first wireless communication processing unit to conduct contactless proximity wireless communication using the proximity wireless communication antenna, a second wireless communication processing unit to conduct wireless communication in a wireless communication format different from that of the first processing unit, a ground potential to be disposed in a surrounding area of the proximity wireless communication antenna and to be connected to a counterpart instrument ground potential when the instrument is in proximity, a detection unit to detect that the counterpart instrument is connected while allowing contactless proximity wireless communication, and a control unit to restrict wireless communication with the second processing unit when the detection unit detects connection and to remove the restriction after connected to the counterpart instrument ground potential with the ground potential during the restriction.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to a communication device carrying out contactless wireless communication in proximity to an antenna of a counterpart device and a communication method that communicates with the communication device. 
         [0003]    2. Description of the Related Art 
         [0004]    In recent years, a variety of devices carrying out contactless wireless communication, by moving a fixed device and a portable device in proximity, between both devices has been put into practical use. For example, such devices are widespread that wirelessly communicates by preparing an instrument, such as a contactless IC card or a wireless tag, as a portable device in proximity to a reader, which is a fixed device. 
         [0005]    In a case of applications for contactless IC cards, wireless tags, and the like, a reader antenna is configured relatively largely and a card or a tag is moved in proximity to a range in which wireless communication with the reader antenna is allowed, thereby enabling wireless communication. Such a range allowing wireless communication may be considered to be within several centimeters from the reader antenna, for example. The configuration of carrying out contactless wireless communication enables to eliminate a restriction of plug and unplug frequencies in such a case of mounting a portable device, such as an IC card having a terminal in the past, to the fixed device via a connector and to improve usability of the portable device. 
         [0006]    Meanwhile, in a case of considering such contactless wireless communication efficiently at high speed of, for example, several or more Gbps, it is considered that a plurality of antennas is respectively disposed in each device and contactless wireless communication is carried out between respective antennas separately to communicate in parallel between the plurality of wireless communication systems. Such high speed contactless proximity wireless communication is applied to data transmission between a variety of information processing devices and peripheral devices thereof, thereby enabling system construction that is free from a restriction of plug and unplug frequencies, such as in a case of connecting peripheral devices with a connector or the like, and allows frequent attachment and removal. 
         [0007]    In addition, such devices are put into practical use that can communicate wirelessly even in a situation distant to some extent or can transmit data with another instrument by building a wireless communication unit, such as a wireless LAN, in respective devices separate from the process of contactless wireless communication by moving two devices in proximity. Normally, in a case of loading a plurality of wireless communication functions in one instrument, respective wireless communication functions are activated independently and there is no relationship with conditions of activating other wireless communication functions. 
         [0008]    Japanese Unexamined Patent Application Publication No. 2005-115511 discloses an example of carrying out contactless wireless communication between instruments in proximity. Japanese Unexamined Patent Application Publication No. 2007-149475 discloses a technique for hot plugging in a case of high speed transmission on a wired transmission channel between a plurality of instruments. 
       SUMMARY OF THE INVENTION 
       [0009]    However, when a plurality of wireless communication functions is loaded in one instrument, a wireless communication behavior in one of them may affect a wireless communication behavior in another. In particular, in a case of a configuration for high speed contactless proximity wireless communication, signals transmitted by the contactless proximity wireless communication turn out to be high frequency signals. Meanwhile, wireless LANs are also prone to have a transmission bandwidth for use of higher in frequency and there is a higher possibility of mutual interference by overlapping the bandwidths to be used for two wireless communication functions. In a case of interference between two wireless communication functions, there has been a problem of a false behavior. 
         [0010]    In the past, as described in Japanese Unexamined Patent Application Publication No. 2007-149475, for example, in a case of connecting a plurality of instruments on a wired transmission channel, it is proposed to take measures not to generate a communication error even in a case of so-called hot plugging where an instrument is removed during data transmission. However, interference between contactless proximity wireless communication and other wireless communication has not been considered in the past. 
         [0011]    It is desirable not to interfere with other wireless communication in a case of carrying out high speed contactless proximity wireless communication. 
         [0012]    An embodiment of the present invention is applied to a device that carries out: a first wireless communication process to carry out contactless proximity wireless communication with a counterpart instrument in proximity using an antenna for proximity wireless communication disposed in a predetermined position; and a second wireless communication process to carry out wireless communication in a wireless communication format different from that of the first wireless communication process. 
         [0013]    Then, the second wireless communication process is restricted in a case that the counterpart instrument with which the antenna for proximity wireless communication wirelessly communicates is connected in a condition of allowing contactless proximity wireless communication is detected. Further, the restriction is removed after a ground potential disposed in a surrounding area of the antenna for proximity wireless communication is connected to a ground potential of the counterpart instrument during the restriction. 
         [0014]    In a case of connected to the counterpart instrument, when the connecting condition is complete, the ground potential in a surrounding area of the antenna for proximity wireless communication is connected to the ground potential of the counterpart instrument and the surrounding area of the antenna for proximity wireless communication becomes shielded, and thus contactless proximity wireless communication can be carried out stably. In contrast, until the connecting condition is stabilized, there is a possibility that the second wireless communication process interferes with the first wireless communication process, which is contactless proximity wireless communication. Therefore, until the connecting condition is stabilized, the second wireless communication process is temporarily restricted and the restriction is removed after connecting the ground potential in the surrounding area of the antenna for proximity wireless communication to the ground potential of the counterpart instrument, thereby not interfering with the first wireless communication process. 
         [0015]    According to an embodiment of the present invention, in a case of carrying out the first wireless communication process as a contactless proximity wireless communication function and the second wireless communication process, which is different from the first process, the second wireless communication process is temporarily restricted when the counterpart instrument is in proximity for contactless proximity wireless communication. The restriction is removed after completing the shielding in the surrounding area of the antenna for a contactless proximity wireless communication function, and contactless proximity wireless communication can be securely carried out without interference from other wireless communication. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0016]      FIG. 1  is a block diagram illustrating a system configuration example according to an embodiment of the present invention; 
           [0017]      FIG. 2  is a perspective view illustrating a configuration example of a portable device according to the embodiment of the present invention; 
           [0018]      FIG. 3  is a perspective view illustrating a configuration example of a base device according to the embodiment of the present invention; 
           [0019]      FIG. 4  is a configuration diagram illustrating a pattern example of an antenna disposition area according to the embodiment of the present invention; 
           [0020]      FIG. 5  illustrates an example of an antenna configuration according to the embodiment of the present invention; 
           [0021]      FIG. 6  is a flowchart showing a communication process example (Example 1) according to the embodiment of the present invention; 
           [0022]      FIG. 7  is a flowchart showing a communication process example (Example 2) according to the embodiment of the present invention; 
           [0023]      FIG. 8  is a flowchart showing a communication process example (Example 3) according to the embodiment of the present invention; 
           [0024]      FIGS. 9A through 9D  are timing charts illustrating a behavioral example (Example 1) while connecting; 
           [0025]      FIGS. 10A through 10E  are timing charts illustrating a behavioral example (Example 2) while connecting; and 
           [0026]      FIGS. 11A through 11G  are timing charts illustrating a behavioral example (Example 3) while connecting. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0027]    A description is given to examples of an embodiment of the present invention in the following order. 
       1. Configuration of Entire System (FIG. 1) 
     2. Configuration of Portable Device (FIG. 2) 
     3. Configuration of Base Device (FIG. 3) 
     4. Example of Antenna Configuration (FIGS. 4,  5 ) 
       [0028]    5. Communication Control Process Example ( FIGS. 6 through 8 )
 
6. Behavioral Examples ( FIGS. 9A through 11G )
 
       7. Description of Modifications of the Embodiment 
     1. Configuration of Entire System 
       [0029]      FIG. 1  illustrates a configuration of the entire communication system. In the present embodiment, this is shown as a system configured with a portable device  100  and a base device  200 . 
         [0030]    The portable device  100  is provided with a main storage unit  154  configured with a memory mechanism, such as a hard disk drive (HDD). The main storage unit  154  may also be a memory mechanism using a semiconductor memory called as a solid state drive (SSD) alternative to an HDD. In the main storage unit  154 , relatively large scale data, such as image data and audio data, is memorized (stored). The portable device  100  is also provided with an index storage unit  155  to memorize index information of the data memorized in the main storage unit  154 . The index storage unit  155  is configured with, for example, a nonvolatile memory. 
         [0031]    Writing in and reading out of the main storage unit  154  and writing and reading the index information in and out of the index storage unit  155  are executed by control of a central processing unit (CPU)  151 . The index information may be memorized directly in the index storage unit  155  when the index information is obtained from outside, while the index information may also be generated by the CPU  151 . 
         [0032]    The portable device  100  is also provided with a wireless communication unit  152 . The wireless communication unit  152  is connected to an antenna  153 , and carries out wireless communication for a wireless LAN defined by, for example, IEEE 802.11 standard. The wireless communication unit  152  carries out relatively close distant wireless communication in a distance of from several meters to approximately 100 meters at most with a counterpart instrument. Wireless communication with the wireless communication unit  152  is activated by a power source from a battery  156 , which is a secondary cell built in the portable device  100 , and the portable device  100  alone (that is, in a condition not to be connected to the base device described later) can wirelessly communicate. 
         [0033]    The wireless communication with the wireless communication unit  152  is executed by control of the CPU  151 , and the index information memorized in the index storage unit  155 , for example, is exchanged with the counterpart instrument. In the present embodiment, there is a case in which wireless communication with the wireless communication unit  152  is temporarily restricted by control of the CPU  151 . Details of processes to restrict the wireless communication and processes to remove the restriction of the wireless communication are described later. 
         [0034]    The main storage unit  154  is also connected to a contactless communication unit  161  and the index storage unit  155  is also connected to a contactless communication unit  162  to carry out contactless wireless communication, respectively, with a base device in proximity to the extent of almost making contact. 
         [0035]    To the respective contactless communication units  161 ,  162 , a plurality of antennas  111  for contactless wireless communication is connected. Although the antennas  111  are connected to the contactless communication unit  161 ,  162  one by one in  FIG. 1 , they are configured with a large number of antennas in practice as described later and are configured to wirelessly transmit data by scattering among the plurality of antennas. A specific example of a configuration of the antennas  111  is described later with  FIGS. 4 and 5 . 
         [0036]    The portable device  100  is also provided with a power detection unit  163  to detect a case of obtaining power at a predetermined voltage in power source terminals  121 ,  122 . In a case of detecting power by the power detection unit  163 , a power detection signal is provided to the CPU  151 . The power detection signal is a signal outputted by detecting that the voltage is stabilized in the power detection unit  163  and the signal is outputted after passing a certain period of time since the power source terminals  121 ,  122  are connected to the base device. 
         [0037]    The portable device  100  is activated by the power obtained by the power source terminals  121 ,  122  other than some units, such as the wireless communication unit  152  and the CPU  151  driven by the battery  156  described previously. The main storage unit  154  and the contactless communication units  161 ,  162  at least are activated by the power obtained by the power source terminals  121 ,  122 . 
         [0038]    The portable device  100  is also provided with connection detection terminals  123 ,  124 , and is configured to output a power output of the battery  156  from the connection detection terminal  124  via a resistor  157 . The connection detection terminal  123  is connected to the CPU  151 , and is configured to detect the voltage obtained by the connection detection terminal  123  as a plugging and unplugging detection signal in the CPU  151 . As illustrated in  FIG. 1 , in a condition of connecting the portable device  100  to the base device  200 , the connection detection terminals  123 ,  124  are conducted via connection detection terminals  252 ,  253  of the base device  200 , and thus the CPU  151  detects connection. The plugging and unplugging detection signal thus detected is a signal that is immediately switched when connecting the portable device  100  to connection units  210  through  240  of the base device  200  described later by placing thereon. 
         [0039]    Next, a description is given to an internal configuration of the base device  200 . 
         [0040]    The base device  200  is provided with a wireless communication unit  262 . The wireless communication unit  262  is connected to an antenna  263 , and is a processing unit carrying out wireless communication in a wireless communication format same as the wireless communication unit  152  of the portable device  100 . That is, the communication unit  262  carries out wireless communication for a wireless LAN defined by, for example, IEEE 802.11 standard. Wireless communication with the wireless communication unit  262  is executed by control of a CPU  261 , and there is no relationship with contactless proximity wireless communication with contactless communication units  264 ,  265  described later. 
         [0041]    By wirelessly communicating with the wireless communication unit  262 , the index information is read out that is memorized in all portable devices  100  existing in the vicinity of the base device  200  to carry out a process of, for example, searching for the portable device  100  in which the desired data is memorized (stored). 
         [0042]    The base device  200  is also provided with the contactless communication units  264 ,  265 , and they are connected respectively to a plurality of antennas  251  for contactless wireless communication. The antennas  251  are connected to the contactless communication units  264 ,  265  one by one in  FIG. 1 , while they are configured with a large number of antennas in practice similar to the portable device  100  and are configured to wirelessly transmit data by scattering among the plurality of antennas. 
         [0043]    The base device  200  is also provided with a power source unit  266  to provide power obtained by converting commercial alternating current power or the like to each unit in the base device  200 . The power source unit  266  is also provided with power source terminals  254 ,  255  and is configured to provide power to the power source terminals  121 ,  122  of the portable device  100  upon connecting to the portable device  100 . 
         [0044]    Although a data process configuration of the base device  200  is omitted in  FIG. 1 , the device can be provided with a variety of processing units, such as a data input unit, a data output unit, an image data processing unit, and a display unit, for example, to be configured to enable data obtained from the portable device  100  to be processed. 
       2. Configuration of Portable Device 
       [0045]      FIG. 2  is an example of a shape of the portable device  100 . 
         [0046]    The portable device  100  is, as illustrated in  FIG. 2 , configured as a housing  101  of a box shape. The housing  101  is configured with, for example, a synthetic resin. 
         [0047]    The housing  101  is made in a thin shape, and has a bottom face  104  with an antenna substrate  110  disposed thereon. The antenna substrate  110  has a surface with a plurality of antennas disposed thereon in parallel. Although details of the configuration and the disposition condition of the antennas are described later, the respective antennas are configured as differential antennas having two straight line conductive areas  303 ,  304  disposed on each surface. 
         [0048]    As illustrated in  FIG. 2 , the straight line conductive areas  303 ,  304  are disposed to extend across the thickness of the housing  101  (in the x direction in  FIG. 2 ). The plurality of antennas are aligned at constant intervals in a direction orthogonal (in the y direction in  FIG. 2 ) to the direction of extending the straight line conductive areas  303 ,  304  (longitudinal direction). A surrounding area of the straight line conductive areas  303 ,  304  configuring the antennas is defined as a ground conductive area  301  ( FIG. 4 ). 
         [0049]    Further, one and the other ends of the housing  101  in a direction orthogonal to the longitudinal direction of the straight line conductive areas  303 ,  304  of each antenna (that is, in the y direction) are tapered slope faces  102  and  103 . The tapered slope faces  102  and  103  are flat surfaces in this example, and are in a shape of narrowing the bottom face  104 , which is a disposition surface of the antenna substrate  110 . In addition, inside the tapered slope faces  102  and  103 , a plate (shield plate) having a shielding action is disposed. 
         [0050]    In a predetermined position of the antenna substrate  110  disposed on the bottom face  104 , the power source terminals  121 ,  122  and the connection detection terminals  123 ,  124  are disposed. These terminals  121  through  124  are disposed in a condition of not connected to the ground conductive area  301 . 
       3. Configuration of Base Device 
       [0051]    Then, with reference to  FIG. 3 , a description is given to a configuration of the base device  200  to which the portable device  100  is connected. 
         [0052]    The base device  200  is provided with, as illustrated in  FIG. 3 , portable device connection units  210 ,  220 ,  230 ,  240 , and portable devices  100  can be connected to the respective connection units  210  through  240  one by one. The example of  FIG. 3  illustrates a condition in which only the connection unit  210  is not connected to the portable device  100  and a condition in which the portable devices  100  are disposed in the three connection units  220 ,  230 ,  240 . Each of the connection units  210  through  240  has a same configuration. 
         [0053]    As illustrated in  FIG. 3 , the portable device connection unit  210  is in a shape of a slot having an elongated indentation formed therein and has tapered slope faces  202 ,  203 , and an antenna disposition surface  204  is provided between both tapered slope faces  202 ,  203 . The disposed distance between the tapered slope faces  202 ,  203  is exactly the same as the disposed distance of the tapered slope faces  102 ,  103  of the portable device  100 , and the slope angle is also the same. Inside the tapered slope faces  202  and  203 , a plate (shield plate) having a shielding action is disposed. 
         [0054]    The antennas disposed on the antenna disposition surface  204  are also disposed in a condition similar to the antennas disposed on the antenna substrate  110  of the portable device  100 . That is, the antenna disposition surface  204  has a plurality of antennas, aligned thereon, respectively having straight line conductive areas  303 ,  304 , and the intervals to align the plurality of antennas and the like are also equal to those of the antenna substrate  110  of the portable device  100 . 
         [0055]    Although not illustrated in  FIG. 3 , the antenna disposition surface  204  has power source terminals  254 ,  255  and connection detection terminals  252 ,  253  corresponding to the power source terminals  121 ,  122  and the connection detection terminals  123 ,  124  of the portable device  100  disposed therein. 
         [0056]    Each of the connection units  210  through  240  of the base device  200  thus configured has a configuration of basically completing connection only by placing the portable device  100  thereon. 4. EXAMPLE OF ANTENNA CONFIGURATION 
         [0057]    Then, a description is given to a configuration of antennas disposed on the antenna substrate  110  of the portable device  100  and a peripheral configuration thereof with reference to  FIGS. 4 and 5 . The antennas themselves on the antenna substrate also have a configuration identical to the antennas disposed on the antenna disposition surface  204  of the base device  200 . 
         [0058]    The antenna substrate  110  is configured with a rigid wiring board. The antenna substrate  110  is in an elongated shape so as to enable disposition on the bottom face  104  of the portable device  100  illustrated in  FIGS. 1 and 2 . 
         [0059]    As illustrated in  FIG. 4 , the surface of the antenna substrate  110  is provided with the ground conductive area  301  across almost the entire surface, and an oval non-conductive area  302  is provided for each antenna disposition area. The non-conductive areas  302  are the portions where no ground conductive area  301  is formed. 
         [0060]    In the respective non-conductive areas  302 , the two straight line conductive areas  303 ,  304  are disposed. The two straight line conductive areas  303 ,  304  are disposed in parallel, where a direction of the thickness (the x direction in  FIG. 2 ) of the portable device  100  is defined as the longitudinal direction. A differential antenna is configured with these two straight line conductive areas  303 ,  304 . 
         [0061]    A length L of the straight line conductive areas  303 ,  304  is, for example, 25 mm and an interval width W between the two straight line conductive areas  303  and  304  is, for example, 6 mm. These values are for one example of a frequency of a signal carrying out wireless communication at a 7.5 GHz band and a transfer rate at 5 Gbps. The numerical values of these dimensions of the antennas of the portable device  100  are equal to these numerical values of the antennas of the base device. 
         [0062]      FIG. 5  illustrates details of one antenna. 
         [0063]    In the oval non-conductive areas  302  surrounded by the ground conductive area  301 , the two straight line conductive areas  303  and  304  having a same thickness are disposed in parallel, and one end of each of the straight line conductive areas  303 ,  304  is provided with feeding points  303   a ,  304   a . The feeding points  303   a ,  304   a  are connected to an antenna connecting conductive area of a communication board  130  via through holes provided in the antenna substrate  110 . A differential signal of an opposite phase to each other is provided to one and the other feeding points  303   a ,  304   a  of one antenna. 
         [0064]    As illustrated in  FIG. 5 , the other end of each of the straight line conductive areas  303 ,  304  is provided with resistor connection points  303   b ,  304   b , and a resistor  305  is connected between the resistor connection points  303   b  and  304   b . The resistor  305  is also disposed on the back side of the antenna substrate  110 . Although the example in  FIG. 5  illustrates an example of connecting with the resistor, they may also be connected with another element. 
         [0065]    The antenna illustrated in  FIG. 5  is disposed in plural and continuously in parallel as illustrated in  FIG. 4 . 
       5. Communication Control Process Example 
       [0066]    Then, a description is given to a controlling process of wireless communication with the wireless communication unit  152  of the portable device  100  with reference to the flowcharts in  FIGS. 6 through 8 . The control of wireless communication with the wireless communication unit  152  is executed by the CPU  151 . 
         [0067]      FIGS. 6 through 8  show different examples, respectively. 
         [0068]    Firstly, the example of  FIG. 6  is described. The CPU  151  is normally in an enabling condition in which wireless communication is allowed for the wireless communication unit  152  (step S 11 ). The enabling condition is a condition to allow wireless communication with the wireless communication unit  152  and wireless communication is carried out with another neighboring instrument (such as the base device) as desired (step S 12 ). That is, in response to a receiving signal in the wireless communication unit  152 , for example, the information memorized in the index storage unit  155  is read out and returned by wireless transmission from the wireless communication unit  152 . 
         [0069]    After that, the CPU  151  determines whether or not connection with the base device  200  is detected by the plugging and unplugging detection signal obtained by the terminal  123  (step S 13 ), and in a condition of not detecting the connection, the enabling condition in step S 11  is continued. 
         [0070]    In contrast, in a case of detecting a change into the connection in step S 13 , the CPU  151  immediately changes into a disenabling condition (step S 14 ) to restrict wireless communication with the wireless communication unit  152 . 
         [0071]    In a case of changing into the disenabling condition in step S 14 , the contactless communication units  161 ,  162  of the portable device  100  are determined whether or not communication with the base device  200  is allowed (step S 15 ). Here, in a case of determining as communication with the base device  200  is allowed, the procedure goes back to step S 11  to change into the enabling condition that allows wireless communication with the wireless communication unit  152  and remove the wireless communication restriction. To allow wireless communication with the contactless communication units  161 ,  162  of the portable device  100  is to be in a condition of supplying power from the power source unit  266  of the connected base device  200  and activating the contactless communication units  161 ,  162 . In a condition of supplying power to the contactless communication units  161 ,  162  for activation, the ground potentials  302  of the antenna substrate  110  of the portable device  100  are connected to ground potentials  211  of the base device  200 , and the shielding of the surrounding area of the antennas is completed. 
         [0072]    Although, in a process example of the flowchart in  FIG. 6 , wireless communication restriction is removed based on the behavioral condition in the contactless communication units  161 ,  162 , it may also be determined whether or not the shielding is completed directly from the condition of the ground potentials  302  of the antenna substrate  110 . 
         [0073]    The flowchart in  FIG. 7  is a process example in such a case. 
         [0074]    To describe the process in  FIG. 7 , the CPU  151  is normally in an enabling condition in which wireless communication is allowed for the wireless communication unit  152  (step S 21 ). In this enabling condition, the wireless communication unit  152  wirelessly communicates with another neighboring instrument as desired (step S 22 ). That is, in response to a receiving signal in the wireless communication unit  152 , for example, the information memorized in the index storage unit  155  is read out and returned by wireless transmission from the wireless communication unit  152 . 
         [0075]    After that, the CPU  151  determines whether or not connection with the base device  200  is detected by the plugging and unplugging detection signal obtained by the terminal  123  (step S 23 ), and in a condition of not detecting the connection, the enabling condition in step S 21  is continued. 
         [0076]    In contrast, in a case of detecting a change into the connection in step S 23 , the CPU  151  immediately changes into a disenabling condition (step S 24 ) to restrict wireless communication with the wireless communication unit  152 . 
         [0077]    In a case of changing into the disenabling condition in step S 24 , the CPU  151  determines whether or not the ground potentials  302  of the antenna substrate  110  are connected to the ground potentials  211  of the base device  200  and the shielding is completed (step S 25 ). Here, the procedure stands by in a case of not completing the shielding, and in a case of completing, the procedure goes back to step S 21  to change into the enabling condition that allows wireless communication with the wireless communication unit  152  and remove the wireless communication restriction. 
         [0078]    The flowchart in  FIG. 8  is to determine completion of shielding from detection of power supply. 
         [0079]    To describe the process in  FIG. 8 , the CPU  151  normally in an enabling condition in which wireless communication is allowed for the wireless communication unit  152  (step S 31 ). In this enabling condition, the wireless communication unit  152  wirelessly communicates with another neighboring instrument as desired (step S 32 ). That is, in response to a receiving signal in the wireless communication unit  152 , for example, the information memorized in the index storage unit  155  is read out and returned by wireless transmission from the wireless communication unit  152 . 
         [0080]    After that, the CPU  151  determines whether or not connection with the base device  200  is detected by the plugging and unplugging detection signal obtained by the terminal  123  (step S 33 ), and in a condition of not detecting the connection, the enabling condition in step S 31  is continued. 
         [0081]    In contrast, in a case of detecting a change into the connection in step S 33 , the CPU  151  immediately changes into a disenabling condition (step S 34 ) to restrict wireless communication with the wireless communication unit  152 . 
         [0082]    In a case of changing into the disenabling condition in step S 34 , the CPU  151  determines whether or not the power supply is started by the power detection signal provided from the power detection unit  163  (step S 35 ). Here, the procedure stands by in a case of not starting power supply, and in a case of starting, the procedure goes back to step S 31  to change into the enabling condition that allows wireless communication with the wireless communication unit  152  and remove the wireless communication restriction. 
       6. Behavioral Examples 
       [0083]    Then, the timing charts in  FIGS. 9A through 11G  illustrates a signal condition in reality when control processing according to the flowcharts in  FIGS. 6 through 8 . 
         [0084]    The processes in  FIGS. 9A through 11G  are almost same from connecting the portable device  100  to the base device  200  until removing the disenabling condition. In  FIGS. 9A through 10E , conditions are illustrated in which the enabling condition driving the main storage unit  154  is limited by the disenabling condition, and in  FIGS. 11A through 11G , the enabling condition is illustrated in which wireless communication with the wireless communication unit  152  is allowed. 
         [0085]    Firstly, to describe the process in  FIGS. 9A through 9D ,  FIG. 9A  illustrates a shielding condition and  FIG. 9B  illustrates a connecting condition of the ground potentials. The condition of  FIG. 9B  being at a low level shows a condition in which the ground potentials are connected to each other and that being at a high level shows a condition in which they are not connected to the counterpart ground potentials. While the condition of  FIG. 9B  is at a low level, as illustrated in  FIG. 9A , a condition in which the ground potentials are connected to each other makes the shield available and a condition of not connected makes the shield unavailable. 
         [0086]      FIG. 9C  illustrates a power detection signal detected by the power detection unit  163 , in which the signal is turned on showing presence of power supply after passing a certain period of time since the shield becomes available. 
         [0087]      FIG. 9D  illustrates whether a driving condition of the main storage unit  154  is enabled or disenabled. In this timing chart of  FIG. 9D , the driving condition is disenabled already in the initial condition, and from such a condition, the power detection signal of  FIG. 9C  is changed from a turned off condition into a turned on condition, thereby becoming into an enabled condition. By becoming into the enabled condition, the main storage unit  154  is started driving to allow the memorized data to be read out and data to be written in. The condition of the main storage unit  154  being driven is also a condition in which contactless proximity wireless communication is carried out with the contactless communication units  161 ,  162 . 
         [0088]    In the example of  FIGS. 9A through 9D , after that, the portable device  100  is removed from the base device  200 , and at the same time of changing the power detection signal of  FIG. 9C  into the turned off condition, the main storage unit  154  is changed from the enabled condition into the disenabled condition as illustrated in  FIG. 9D  not to be activated. 
         [0089]    In the example of  FIGS. 10A through 10E , a removal signal is generated upon removing the portable device  100  is from the base device  200  to change the main storage unit  154  and the contactless communication units  161 ,  162  into a disenabled condition. 
         [0090]    That is, a shielding condition of  FIG. 10A , a connecting condition of the ground potentials of  FIG. 10B , and a power detection condition of  FIG. 10C  are same as each condition illustrated in  FIGS. 9A through 9C . 
         [0091]    In the example of  FIGS. 10A through 10E , upon removing, a removal allowance signal illustrated in  FIG. 10E  is generated by the base device  200 . The removal allowance signal is generated upon, for example, pressing a removal button provided in the base device  200 . The removal allowance signal is transmitted via, for example, contactless proximity wireless communication to the portable device  100 . 
         [0092]    As the removal allowance signal is provided to the CPU  151  of the portable device  100 , the CPU  151  is changed into a disenabled condition as illustrated in  FIG. 10D  to remove the portable device  100  in such a condition. After that, by removing the portable device  100 , the power source is turned off and the power detection condition of  FIG. 10C  becomes turned off and the shielding condition also becomes unavailable. 
         [0093]    An example of  FIGS. 11A through 11G  illustrates, from conditions of the plugging and unplugging signal and the power detection signal, an example of controlling the driving condition of the main storage unit  154  and the contactless communication units  161 ,  162  and the condition of wireless communication allowance for the wireless communication unit  152 . This example of  FIGS. 11A through 11G  is equivalent to the processes shown in the flowcharts of  FIGS. 6 through 8 . 
         [0094]      FIG. 11A  illustrates a condition of the plugging and unplugging signal obtained by the terminal  123  ( FIG. 1 ), which firstly changes when connecting the portable device  100  to the base device  200 . 
         [0095]    The change of the plugging and unplugging signal changes, as illustrated in  FIG. 11G , the condition of the wireless communication unit  152  from the enabled condition into the disenabled condition and temporarily restricts wireless communication. After that, as understood from the shielding condition of  FIG. 11B , the connecting condition of the ground potentials of  FIG. 11C , and the condition of the power detection signal of  FIG. 11D , the shield connection is completed and it becomes in a condition of supplying power to change into the enabled condition as illustrated in  FIG. 11G . Due to the change from the disenabled condition into the enabled condition, the restriction of wireless communication with the wireless communication unit  152  is removed. 
         [0096]    After the power detection signal is turned on to be stabilized, as illustrated in  FIG. 11E , the driving conditions of the main storage unit  154  and the contactless communication units  161 ,  162  are changed into the enabled condition. The process for connection is up to here. 
         [0097]    Then, the process for removal is described. 
         [0098]    As illustrated in  FIG. 11F , as the removal allowance signal is provided to the CPU  151  of the portable device  100 , the CPU  151  changes the driving condition of the main storage unit  154  and the contactless communication units  161 ,  162  into a disenabled condition as illustrated in  FIG. 11D . 
         [0099]    Further, by turning off the power detection condition of  FIG. 11C , the condition of the wireless communication unit  152  is changed into a disenabled condition as illustrated in  FIG. 11G  and wireless communication is temporarily restricted. After that, as removal is detected by the plugging and unplugging signal illustrated in  FIG. 11A , the condition of the wireless communication unit  152  is changed into an enabled condition as illustrated in  FIG. 11G  and the restriction of wireless communication is removed. 
         [0100]    By changing as illustrated in  FIGS. 11A to 11G , wireless communication with the wireless communication unit  152  is temporarily restricted until completing the shielding of the surrounding area of the antennas for contactless proximity communication when connecting and the restriction is removed as the shielding is completed. Accordingly, in a condition of not completing the shielding of the surrounding area of the antennas for contactless proximity communication, wireless communication with the wireless communication unit  152  and contactless proximity communication with the contactless communication units  161 ,  162  are not carried out at the same time and does not interfere with the contactless communication units  161 ,  162 . Since, in a condition of completing the shielding, the shielding condition suppresses interference from outside, there is no problem to carry out wireless communication with the wireless communication unit  152  and contactless proximity communication with the contactless communication units  161 ,  162  at the same time. 
         [0101]    In addition, wireless communication is also temporarily restricted upon removal, thereby not carrying out wireless communication while the shielding of the surrounding area of the antennas for contactless proximity communication is removed, and thus from this perspective, respective communication is not carried out in a condition of interfering with the units  161 ,  162 . 
       7. Description of Modifications of the Embodiment 
       [0102]    While the disposition of the antennas illustrated in each drawing are illustrated relatively largely for the ease of understanding the configuration, a larger number of antennas smaller in size than those in drawings may also be disposed. Although the plurality of antennas is disposed in one array in the examples illustrated in  FIG. 4  and the like, the antennas may also be disposed in a plurality of arrays, such as in two or more arrays. 
         [0103]    Although the configuration of the antenna elements themselves are described as differential antennas in which two straight line conductive areas are disposed in parallel to provide a differential signal, it may also be antennas configured with one straight line conductor. It should be noted that, by configuring the antennas as the differential antennas illustrated in detail in  FIG. 5  for wireless transmission of a differential signal, contactless proximity wireless communication using a high frequency signal can be carried out at high transmission efficiency. 
         [0104]    Regarding separate usages of the antennas disposed in plural, although they are described only as simply being used in parallel, the antennas may also be used for more sophisticated separation, such as to be separated into a group of antennas used for transmission and a group of antennas used for reception, for example. 
         [0105]    In addition, the configurations of the portable device  100  and the base device  200  illustrated in  FIGS. 1 through 3  merely illustrates one preferred example and they may also be in another form. Further, although the portable device  100  illustrated as a configuration example in  FIG. 1  is described as a device for memorizing (storing) data, it may also be configured as a device for other process. 
         [0106]    In addition, regarding the configuration of antennas illustrated in  FIG. 4  and the like, the straight line conductive areas  303 ,  304  on the antenna substrate configuring the antennas are exposed. In contrast, it may also be in a configuration of not exposing the electrode members by disposing a protective member of some sort on the surface upon disposed in the portable device  100  or the base device  200 . 
         [0107]    The present application contains subject matter related to that disclosed in Japanese Priority Patent Application JP 2009-180902 filed in the Japan Patent Office on Aug. 3, 2009, the entire content of which is hereby incorporated by reference. 
         [0108]    It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and alterations may occur depending on design requirements and other factors insofar as they are within the scope of the appended claims or the equivalents thereof.