Abstract:
A handheld electronic device and display method for a handheld electronic device provide for an initialization screen to be displayed by a display unit, in response to user input, to display symbols reflecting an intent of the user. The handheld electronic device includes a user input unit having a first key to which a symbol of a first type is allocated and a symbol of a second type is not allocated, and a second key to which a symbol of the first type and a symbol of the second type are both allocated; a display unit that, upon input via the user input unit, displays a symbol of the first type and/or a symbol of the second type; and a control unit that controls what the display unit displays.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is the National Stage of International Application No. PCT/JP2010/064585, filed Aug. 27, 2010, which claims the benefit of Japanese Application No. 2009-196571, filed Aug. 27, 2009, the entire contents of both of which are incorporated by reference herein. 
     FIELD OF THE INVENTION 
     The present invention relates to a portable electronic device and a display method for the portable electronic device, in which the portable electronic device includes: operation keys assigned with nonnumeric characters but not numeric characters; and operation keys assigned with the nonnumeric characters and the numeric characters. 
     BACKGROUND OF THE INVENTION 
     Some portable electronic devices such as cellular telephone devices and the like include: an operation unit that is configured to include first keys assigned with nonnumeric characters but not numeric characters, and second keys assigned with the nonnumeric characters and the numeric characters; a display unit that displays at least one of the nonnumeric characters and the numeric characters in accordance with an operation of the operation unit; and a control unit that controls content displayed on the display unit (for example, see Patent Document 1).
     Patent Document 1: Japanese Unexamined Patent Application, Publication No. 2006-293965   

     SUMMARY OF THE INVENTION 
     Problems to be Solved by the Invention  
     In a cellular telephone device, a display unit displays an initial screen while waiting for an incoming call, and while waiting for activation of an application. However, in the cellular telephone device, in a case in which any one of first keys is operated while the initial screen is displayed on the display unit, the display unit has not been capable of displaying a character corresponding to the first key thus operated. Moreover, in the cellular telephone device, in a case in which any one of second keys is operated while the initial screen is displayed on the display unit, although the display unit has been capable of displaying a numeric character corresponding to the second key thus operated, the display unit has not been capable of displaying a nonnumeric character corresponding to the second key thus operated. 
     An object of the present invention is to provide a portable electronic device and a display method for the portable electronic device, which are capable of displaying characters reflecting a user&#39;s intention, in accordance with characters assigned to the operated keys while the initial screen is displayed on the display unit. 
     Means for Solving the Problems 
     A portable electronic device according to the present invention includes: an operation unit that includes first keys assigned with first type characters but not assigned with second type characters, and second keys assigned with the first type characters and the second type characters; a display unit that displays at least one of the first type characters and the second type characters in accordance with an operation of the operation unit; and a control unit that controls content displayed on the display unit; in which, in a state where an initial screen is displayed on the display unit, in a case in which any one of the first keys is operated, the control unit displays the first type character assigned to the first key thus operated on the display unit, and in a case in which any one of the second keys is operated, the control unit displays the first type character and the second type character assigned to the second key thus operated on the display unit. 
     Moreover, in a state where the first type character and second type character are displayed on the display unit as a result of operating the second key, in a case in which any one of the first keys is operated, the control unit preferably cancels displaying the second type character displayed on the display unit. 
     In addition, the operation unit preferably includes a plurality of the first keys, and the control unit preferably cancels displaying the second type character in a case in which the plurality of first keys are operated more than a predetermined number of times. 
     Furthermore, the portable electronic device preferably further includes a communication unit, wherein the second type characters are preferably numeric characters, the operation unit preferably includes a calling key assigned with none of the first type characters and the second type characters, and in a state where the numeric characters are displayed on the display unit as a result of operating the second keys, when the calling key is operated, the control unit preferably controls the communication unit to make a call to a communication party represented by the numeric characters displayed on the display unit. 
     Moreover, in the portable electronic device, the first type characters are preferably alphabetic characters, and the second type characters are preferably numeric characters, and in a state where the alphabetic characters and the numeric characters are displayed on the display unit as a result of operating the second keys, in a case in which the alphabetic characters cannot be converted into Japanese kana characters, the control unit preferably cancels displaying the alphabetic characters displayed on the display unit. 
     In addition, the operation unit preferably further includes: a first body in which the display unit is disposed; and a second body in which the operation unit is disposed, the second body configuring an opened state by moving in relation to the first body, or configuring a closed state by being disposed so as to be superimposed on the first body, and in the opened state of the first body and the second body, in a state where the first type characters and second type characters are displayed on the display unit as a result of operating the second keys, in a case in which the control unit detects transition from the opened state to the closed state, the control unit preferably cancels displaying the first type characters displayed on the display unit. 
     Furthermore, in a case of detecting transition to the opened state within a predetermined period of time after detecting transition from the opened state to the closed state, the control unit preferably displays the first type characters, whose display has been cancelled, on the display unit again. 
     Moreover, a portable electronic device according to the present invention includes a first body and a second body, in which the first body including a first operation unit and the second body including a second operation unit are connected so as to be openable and closable; the second operation unit is covered with the first body in a closed state, and is exposed to the outside in an opened state; the first operation unit is exposed to the outside in both the closed state and the opened state; the portable electronic device comprising: a display unit that displays at least one of first type characters and second type characters in accordance with an operation of the first operation unit or the second operation unit; and a control unit that controls content displayed on the display unit; in which the first operation unit includes first keys assigned with the first type characters and the second type characters; the second operation unit includes second keys assigned with the first type characters but not assigned with the second type characters; and third keys assigned with the first type characters and the second type characters; and in a state where an initial screen is displayed on the display unit, in a case in which any one of the first keys is operated, the control unit displays the second type character assigned to the first key thus operated on the display unit, and in a case in which any one of the second keys or the third keys is operated, the control unit displays the first type character assigned to the second key or the third key thus operated on the display unit. 
     In addition, a display method for a portable electronic device according to the present invention is a display method applied to a portable electronic device that includes: an operation unit that is configured to include first keys assigned with first type characters but not assigned with second type characters, and second keys assigned with the first type characters and the second type characters; and a display unit that displays at least one of the first type characters and the second type characters in accordance with an operation of the operation unit; in which, in a state where an initial screen is displayed on the display unit, in a case in which any one of the first keys is operated, the method displays the first type character assigned to the first key thus operated on the display unit, and in a case in which any one of the second keys is operated, the method displays the first type character and the second type character assigned to the second key thus operated on the display unit. 
     Effects of the Invention 
     According to the present invention, in a case in which an initial screen is displayed on a display unit, it is possible to display characters reflecting the user&#39;s intention in accordance with an operation. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an external perspective view of a cellular telephone device as a first embodiment of a portable electronic device; 
         FIG. 2  is a block diagram showing a functional configuration of the cellular telephone device as the first embodiment of the portable electronic device; 
         FIG. 3  is a diagram illustrating a first transition of a display mode of a display unit; 
         FIG. 4  is a flowchart showing a first operation of the cellular telephone device; 
         FIG. 5  is a diagram illustrating a second transition of the display mode of the display unit; 
         FIG. 6  is a flowchart showing a second operation of the cellular telephone device; 
         FIG. 7  is a diagram illustrating a third transition of the display mode of the display unit; 
         FIG. 8  is a flowchart showing a third operation of the cellular telephone device; 
         FIG. 9  is a diagram illustrating a fourth transition of the display mode of the display unit; 
         FIG. 10  is a flowchart showing a fourth operation of the cellular telephone device; 
         FIG. 11  is an external perspective view of the cellular telephone device as a second embodiment of the portable electronic device; and 
         FIG. 12  is a block diagram showing a functional configuration of the cellular telephone device as the second embodiment of the portable electronic device. 
     
    
    
     EXPLANATION OF REFERENCE NUMERALS 
     
         
         
           
               1  cellular telephone device (portable electronic device) 
               2  cellular telephone device (portable electronic device) 
               10  first body 
               12  display unit 
               20  second body 
               22  operation unit 
               35  control unit 
               40  initial screen 
               41  first type character display area 
               42  second type character display area 
               50  first operation unit 
               51  second operation unit 
               221  first key 
               222  second key 
               501  first key 
               511  second key 
               512  third key 
           
         
       
    
     DETAILED DESCRIPTION OF THE INVENTION 
     First Embodiment 
     Descriptions are provided hereinafter regarding preferred embodiments for carrying out the present invention with reference to the drawings. First, with reference to  FIG. 1 , descriptions are provided regarding a basic structure of a cellular telephone device  1  as a first embodiment of the portable electronic device of the present invention. 
       FIG. 1  is an external perspective view of the cellular telephone device  1  as the first embodiment of the portable electronic device. 
     The cellular telephone device  1  includes a first body  10  and a second body  20 . 
     A display unit  12  is disposed on a front face  11  of the first body  10 . The display unit  12  displays at least one of first type characters and second type characters in accordance with an operation of an operation unit  22  that will be described later. Moreover, the display unit  12  displays various types of information (nonnumeric character information, numeric character information, and image information) such as telephone numbers, email addresses of communication parties, and email content. 
     In addition, a microphone  13  and a receiver  14  are disposed on the front face  11  of the first body  10 . The microphone  13  is used for inputting sound produced by a user of the cellular telephone device  1  during a telephone call. The receiver  14  outputs sound of communication parties. 
     Furthermore, a speaker  15  (see  FIG. 2 ) is disposed on a side face of the first body  10 . The speaker  15  outputs sound or the like giving notification of an incoming call to the cellular telephone device  1 . 
     An operation unit  22  is disposed on a front face  21  of the second body  20 . The front face  21  of the second body  20  is a face opposing a rear face of the first body  10  (a face opposite to the front face  11  of the first body  10 ) 
     The second body  20  configures an opened state by moving in relation to the first body  10 , or configures a closed state by being disposed so as to be superimposed on the first body  10 . In other words, the cellular telephone device  1  configures the closed state when the first body  10  and the second body  20  are disposed so as to be superimposed on each other in a planar view. Moreover, as shown in  FIG. 1 , the cellular telephone device  1  configures the opened state when the second body  20  is pulled out laterally in relation to the first body (or when the first body  10  is pushed out laterally in relation to the second body  20 ). 
     The operation unit  22  is operational when the first body  10  and the second body  20  are moved in relation to each other to transition to the opened state. The operation unit  22  includes first keys  221  assigned with the first type characters, and second keys  222  assigned with the first type characters and the second type characters. 
     Next, descriptions are provided regarding a functional configuration of the cellular telephone device  1  with reference to  FIG. 2 . 
       FIG. 2  is a block diagram showing a functional configuration of the cellular telephone device  1 . The cellular telephone device  1  includes the operation unit  22 , the microphone  13 , the display unit  12 , the receiver  14 , the speaker  15 , a driver IC  30 , a communication unit  31 , an image processing unit  32 , a sound processing unit  33 , a storage unit  34 , and a control unit  35 . 
     The communication unit  31  is configured to include a main antenna  311  and an RF circuit unit  312 , and performs communication with predetermined communication parties. Examples of the communication parties with which the communication unit  31  performs communication include an outside terminal device that makes a telephone call or transmission/reception of email with the cellular telephone device  1 , or an external device such as an outside web server with which the cellular telephone device  1  establishes an Internet connection. 
     The main antenna  311  performs communication with an external device with a predetermined usable frequency band. 
     The RF circuit unit  312  executes demodulation processing on a signal received via the main antenna  311 , and transmits the signal thus processed to the control unit  35 . Moreover, the RF circuit unit  312  executes modulation processing on the signal transmitted from the control unit  35 , and transmits the signal to external devices (base stations) via the main antenna  311 . 
     The image processing unit  32  executes predetermined image processing, and outputs the processed image data to the driver IC  30 , according to control by the control unit  35 . When the image data is transmitted from the image processing unit  32 , the driver IC  30  stores the image data in frame memory (not illustrated), and outputs the image data to the display unit  12  at predetermined timing. 
     The sound processing unit  33  executes predetermined sound processing on a signal transmitted from the RF circuit unit  312  according to control by the control unit  35 , and outputs the signal thus processed to the receiver  14  or the speaker  15 . The receiver  14  or the speaker  15  externally outputs the signal transmitted from the sound processing unit  33 . 
     In addition, when a signal is input from the microphone  13 , the sound processing unit  33  processes the signal, and outputs the signal thus processed to the RF circuit unit  312 , according to control by the control unit  35 . The RF circuit unit  312  executes predetermined processing on the signal transmitted from the sound processing unit  33 , and transmits the signal thus processed to the main antenna  311  that externally outputs the signal as radio waves. 
     The storage unit  34  includes, for example, working memory, and is utilized for arithmetic processing by the control unit  35 . Furthermore, the storage unit  34  stores data, tables and the like, which are utilized by various applications running on the cellular telephone device  1 . It should be noted that the memory  34  may be a detachable external memory. 
     The control unit  35  controls the entirety of the cellular telephone device  1 , and performs predetermined control of the display unit  12 , the communication unit  31 , the image processing unit  32 , and the sound processing unit  33 . Specific operations of the control unit  35  will be described later. 
     The cellular telephone device  1  that is configured as above has a function such that, in a case in which an initial screen is displayed on the display unit  12 , characters reflecting the user&#39;s intention are displayed in accordance with the characters assigned to the operated keys. 
     Descriptions are hereinafter provided regarding a configuration and operations for achieving the abovementioned function according to the cellular telephone device  1 . 
     First, descriptions are provided regarding a configuration for achieving the abovementioned function of the cellular telephone device  1  according to the present embodiment. 
     The cellular telephone device  1  includes the operation unit  22  and the display unit  12 . 
     As shown in  FIG. 1 , the operation unit  22  includes the first keys  221  assigned with the first type characters but not second type characters, and the second keys  222  assigned with the first type characters and the second type characters. The first keys  221  and the second keys  222  are, for example, keys in a QWERTY keyboard as shown in  FIG. 1 . It should be noted that the keys assigned with the first type characters and second type characters are not limited to the example shown in  FIG. 1 . 
     The display unit  12  displays at least one of the first type characters and the second type characters in accordance with an operation of the operation unit  22 , and includes at least one of a first type character display area  41  that displays the first type characters, and a second type character display area  42  that displays the second type characters. When an initial screen  40  is displayed on the display unit  12  (see  FIG. 3A ), in a case in which any one of the second keys  222  is depressed, the display area of the display unit  12  is divided into the first type character display area  41  that displays the first type characters, and the second type character display area  42  that displays the second type characters (see  FIG. 3B ). 
     The character string of the second type characters displayed in the second type character display area  42  serves as a telephone number. Therefore, in a case in which a calling key  223  is depressed in a state where the telephone number is displayed in the second type character display area  42 , the cellular telephone device  1  can make an outgoing telephone call. 
     It should be noted that the first type characters are nonnumeric characters such as alphabetic characters, hiragana characters, katakana characters and kanji characters. Moreover, the second type characters are numeric characters and, for example, symbols utilized for an outgoing telephone call, such as “# (hash mark)”, “* (asterisk)”, “- (hyphen)”, “P (pause)” and the like. 
     The control unit  35  controls content displayed on the display unit  12 . 
     In a state where the initial screen  40  is displayed on the display unit  12 , in a case in which any one of the first keys  221  is operated, the control unit  35  displays the first type character assigned to the operated first key  221  on the display unit  12 , and in a case in which any one of the second keys  222  is operated, the control unit  35  displays the first type character and the second type character assigned to the operated second key  222  on the display unit  12 . Here, the initial screen  40  is a so-called wallpaper screen on standby for communication, in which neither the email application nor the memo pad application is activated. 
     In other words, in a case in which any one of the first keys  221  is operated, the control unit  35  displays the first type character in the first type character display area  41  of the display unit  12 . In addition, in a case in which any one of the second keys  222  is operated, the control unit  35  displays the first type character in the first type character display area  41  of the display unit  12 , and displays the second type character in the second type character display area  42  of the display unit  12 . For example, as shown in  FIG. 3B , in a case in which a second key  222  assigned with an alphabetic character “A” and a numeric character “4” is depressed, the control unit  35  displays a hiragana character with the pronunciation “a” in the first type character display area  41  of the display unit  12 , and displays the numeric character “4” in the second type character display area  42  of the display unit  12 . It should be noted that since the control unit  35  is set to perform Japanese kana conversion in the present example, even in a case in which the second key  222  assigned with the alphabetic character “A” is depressed, the control unit  35  displays the hiragana character with the pronunciation “a” on the display unit  12 . 
     Therefore, in a case in which the initial screen  40  is displayed on the display unit  12 , the cellular telephone device  1  can display characters reflecting the user&#39;s intention in accordance with the characters assigned to the operated keys. 
     In other words, in a case in which any one of the first keys  221  assigned with the first type character (nonnumeric character) is operated, the cellular telephone device  1  displays a character corresponding to the first key  221 . Furthermore, in a case in which any one of the second keys  222  assigned with the first type character (nonnumeric character) and the second type character (numeric character) is operated, the cellular telephone device  1  parallely displays the first type character (nonnumeric character) and the second type character (numeric character) corresponding to the second key  222  on the display unit  12 . As a result, the cellular telephone device  1  can make a display that reflects the user&#39;s intention. 
     Moreover, in a state where the first type character and second type character are displayed on the display unit  12  as a result of operating any one of the second keys  222 , in a case in which any one of the first keys  221  is operated, the control unit  35  cancels displaying the second type character displayed on the display unit  12 . 
     In other words, in a state where the first type character is displayed in the first type character display area  41 , and the second type character is displayed in the second type character display area  42  as a result of depressing any one of the second keys  222 , in a case in which any one of the first keys  221  is depressed, the control unit  35  cancels displaying the second type character display area  42  from the display unit  12 , and displays only the first type character display area  41  on the display unit  12  (see  FIG. 3C ). 
     Therefore, in a state where the first type character (nonnumeric character) and the second type character (numeric character) corresponding to the second key  222  are parallely displayed on the display unit  12  as a result of operating the second key  222  assigned with the first type character (nonnumeric character) and the second type character (numeric character), in a case in which any one of the first keys  221  assigned with the first type character (nonnumeric character) is operated, a switch is made to display only the first type characters (nonnumeric characters); accordingly, it is possible to make a display that reflects the user&#39;s intention. 
     In addition, the cellular telephone device  1  has the plurality of first keys  221 . Furthermore, in a state where the first type character and second type character are displayed on the display unit  12  as a result of operating any one of the second keys  222 , in a case in which the first keys  221  are operated more than a predetermined number of times, the control unit  35  cancels displaying the second type character displayed on the display unit  12 . 
     In other words, in a state where the first type character display area  41  and the second type character display area  42  are displayed on the display unit  12 , in a case in which the plurality of first keys  221  are operated more than a predetermined number of times, the control unit  35  cancels displaying the second type character display area  42  from the display unit  12 , and displays only the first type character display area  41  on the display unit  12 . It should be noted that the predetermined number of times may be appropriately set by the user. 
     Therefore, in a state where the first type character (nonnumeric character) and the second type character (numeric character) corresponding to the second key  222  are parallely displayed on the display unit  12  as a result of operating the second key  222  assigned with the first type character (nonnumeric character) and the second type character (numeric character), in a case in which the first keys  221  assigned with the first type character (nonnumeric character) are operated more than a predetermined number of times, the cellular telephone device  1  displays only the first type character (nonnumeric character); accordingly, it is possible to prevent an incorrect display due to incorrect input, and to make a display that reflects the user&#39;s intention. 
     Moreover, in the cellular telephone device  1 , the plurality of first keys  221  compose a first key group  221   a . In addition, in a case in which the first keys  221  composing the first key group  221   a  are operated more than a predetermined number of times, the control unit  35  cancels displaying the second type characters. 
     In other words, in a state where the first type character display area  41  and the second type character display area  42  are displayed on the display unit  12 , in a case in which the first keys  221  composing the first key group  221   a  are operated more than a predetermined number of times, the control unit  35  cancels displaying the second type character display area  42  from the display unit  12 , and displays only the first type character display area  41  on the display unit  12 . 
     Therefore, in a state where the first type character (nonnumeric character) and the second type character (numeric character) corresponding to the second key  222  are parallely displayed on the display unit  12  as a result of operating the second key  222  assigned with the first type character (nonnumeric character) and the second type character (numeric character), in a case in which the first keys  221  in the first key group  221   a  assigned with the first type characters (nonnumeric characters) are operated more than a predetermined number of times, the cellular telephone device  1  displays only the first type characters (nonnumeric characters); accordingly, it is possible to prevent an incorrect display due to incorrect input, and to make a display that reflects the user&#39;s intention. 
     The cellular telephone device  1  further includes the communication unit  31 . Furthermore, the first type characters are alphabetic characters, and the second type characters are numeric characters. 
     Moreover, the operation unit  22  has the calling key  223  (see  FIG. 1 ), to which none of alphabetic characters and numeric characters are assigned. It should be noted that the position for disposing the calling key  223  is not limited to the position shown in  FIG. 1 , and may be another position. In other words, a telephone calling function may be assigned to any one of the plurality of keys that compose the operation unit  22 . In addition, the calling key  223  is not limited to being disposed in the first body  10 , and may be disposed in the second body  20 . 
     Furthermore, in a state where numeric characters are displayed on the display unit  12  as a result of operating the second keys  222 , when the calling key  223  is operated, the control unit  35  controls the communication unit  31  to make a call by using the numeric characters displayed on the display unit  12  as a telephone number of a communication party. 
     In other words, in a state where alphabetic characters are displayed in the first type character display area  41 , and numeric characters are displayed in the second type character display area  42 , in a case in which the calling key  223  is operated, the control unit  35  uses the numeric characters displayed in the second type character display area  42  as a telephone number, and makes a call to the telephone number. It should be noted that Japanese kana characters (hiragana characters and katakana characters) converted from alphabetic characters that were input based on an operation of the second keys  222 , or other characters (kanji characters) further converted from the converted kana characters may be displayed in the first type character display area  41 . 
     Therefore, even in a case in which an alphabetic character string and a numeric character string are parallely displayed on the display unit  12 , the cellular telephone device  1  can make a telephone call to a telephone number (the numeric character string) displayed on the display unit  12 , based on an operation of the calling key  223 . 
     Moreover, the first type characters are alphabetic characters, and the second type characters are numeric characters. In addition, in a state where alphabetic characters and numeric characters are displayed on the display unit  12  as a result of operating the second keys  222 , in a case in which the alphabetic characters cannot be converted into Japanese kana characters, the control unit  35  cancels displaying the alphabetic characters displayed on the display unit  12 . 
     Here, descriptions are provided regarding Japanese kana conversion. In a case of performing Japanese kana conversion, the storage unit  34  of the cellular telephone device  1  stores a conversion table that is utilized for converting alphabetic characters into Japanese kana characters. The conversion table contains Japanese kana characters each corresponding to a consonant and a vowel. For example, in the conversion table, a hiragana character with the pronunciation “sa” is associated with a consonant “s” and a vowel “a”; and a hiragana character with the pronunciation “yo” is associated with a consonant “y” and a vowel “o”. Furthermore, in a case in which alphabetic characters are input by depressing the second keys  222 , the control unit  35  refers to the conversion table to distinguish a Japanese kana character that is associated with a consonant and a vowel of the alphabetic characters. 
     Incidentally, in a case in which, for example, consonants are consecutively input (for example, in a case in which an alphabetic character string “rcrsd” is input), such a character string cannot be converted into Japanese kana characters. In this way, in a case in which alphabetic characters were input by depressing the second keys  222 , and the input alphabetic characters cannot be converted into Japanese kana characters, the control unit  35  cancels displaying the first type character display area  41  from the display unit  12 , and displays only the second type character display area  42  on the display unit  12 . 
     It should be noted that in a case in which more than a predetermined number of consonant characters are consecutively input, the control unit  35  can cancel displaying the first type character display area  41  from the display unit  12 , and display only the second type character display area  42  on the display unit  12 . 
     Therefore, in a state where the first type characters (nonnumeric characters) and the second type characters (numeric characters) corresponding to the operated second keys  222  are parallely displayed on the display unit  12  as a result of operating the first keys  221  assigned with the first type characters (nonnumeric characters) or the second keys  222  assigned with the first type characters (nonnumeric characters) and the second type characters (numeric characters), in a case in which the first type characters (alphabetic characters) displayed in the first type character display area  41  of the display unit  12  cannot be converted into Japanese kana characters, the cellular telephone device  1  displays only the second type character display area  42  on the display unit  12 ; accordingly, it is possible to make a display that reflects the user&#39;s intention. 
     The cellular telephone device  1  further includes the first body  10  and the second body  20 . 
     The display unit  12  is disposed to the first body  10 . 
     The operation unit  22  is disposed in the second body  20 . In addition, the second body  20  configures the opened state by moving in relation to the first body  10 , or configures the closed state by being disposed so as to be superimposed on the first body  10 . 
     In other words, the cellular telephone device  1  is a slider type cellular telephone device or a turning type cellular telephone device, in which the first body  10  and the second body  20  are moved in relation to each other. 
     In the opened state of the first body  10  and the second body  20 , in a state where the first type characters and second type characters are displayed on the display unit  12  as a result of operating the second keys  222 , in a case in which the control unit  35  detects transition from the opened state to the closed state, the control unit  35  cancels displaying the first type characters displayed on the display unit  12 . 
     In other words, when the first body  10  and the second body  20  are moved in relation to each other to transition to the opened state, and the first type character display area  41  and the second type character display area  42  are displayed on the display unit  12 , in a case in which the first body  10  and the second body  20  are moved relatively to transition from the opened state to the closed state, the control unit  35  determines that a telephone call will be made, cancels displaying the first type character display area  41  from the display unit  12 , and displays only the second type character display area  42  on the display unit  12 . 
     It should be noted that transition from the opened state to the closed state of the first body  10  and the second body  20  may be detected, and display control according to the control unit  35  may be performed, for example, as follows. In other words, a detecting unit (not illustrated), which detects the closed state in which the first body  10  and the second body  20  are superimposed on each other, is provided to at least one of the first body  10  and the second body  20 . When the detecting unit detects the closed state of the first body  10  and the second body  20 , the detecting unit transmits a trigger signal indicating a detection result to the control unit  35 . When the control unit  35  receives the trigger signal from the detecting unit, the control unit  35  cancels displaying the first type character display area  41  from the display unit  12 , and displays only the second type character display area  42  on the display unit  12 . 
     Therefore, in a state where the first type characters (nonnumeric characters) and the second type characters (numeric characters) corresponding to the second keys  222  are parallely displayed on the display unit  12  as a result of operating the second keys  222  assigned with the first type characters (nonnumeric characters) and the second type characters (numeric characters) in the opened state of the first body  10  and the second body  20 , in a case in which the first body  10  and the second body  20  transitions from the opened state to the closed state, the cellular telephone device  1  determines that the display of the first type characters (nonnumeric characters) is unnecessary, and thus switches to display only the second type characters (numeric characters); accordingly, it is possible to make a display that reflects the user&#39;s intention. 
     Furthermore, in a case of detecting a transition to the opened state within a predetermined period of time after detecting a transition from the opened state to the closed state of the first body  10  and the second body  20 , the control unit  35  displays the first type characters, whose display has been cancelled, on the display unit  12  again. 
     In other words, in a case in which the first body  10  and the second body  20  transition to the closed state, and as a result, only the second type character display area  42  is displayed on the display unit  12 , the control unit  35  stores the first type characters displayed in the first type character display area  41  to the storage unit  34 . In addition, in a case in which the first body  10  and the second body  20  transition to the opened state again within a predetermined period of time after the first body  10  and the second body  20  have transitioned to the closed state, the detecting unit (not illustrated) detects that the first body  10  and the second body  20  are not in the closed state (i.e. transitioned to the opened state), and transmits the detection result as a trigger signal to the control unit  35 . When the control unit  35  receives the trigger signal from the detecting unit, the control unit  35  displays the first type character display area  41  and the second type character display area  42  on the display unit  12 , further reads the first type characters stored in the storage unit  34 , and displays the first type characters in the first type character display area  41 . 
     Therefore, in a case in which the first body  10  and the second body  20  transition to the opened state again within a predetermined period of time after the first body  10  and the second body  20  transitioned from the opened state to the closed state, the cellular telephone device  1  displays the first type characters, whose display has been cancelled when the first body  10  and the second body  20  transitioned from the opened state to the closed state, again in the first type character display area  41  of the display unit  12 ; accordingly, it is possible to prevent an incorrect display due to erroneous opening and closing of the first body  10  and the second body  20 , and it is possible to make a display that reflects the user&#39;s intention. 
     Here, in the aforementioned embodiment, descriptions have been provided regarding conversion of alphabetic characters into Japanese kana characters in a case in which any one of the first keys  221  and the second keys  222  is operated once or a plurality of times. However, the present invention is not limited to this example, and it is also possible for alphabetic characters not to be converted into Japanese kana characters. 
     In this modified example, in a case in which, for example, a second key  222  assigned with an alphabetic character “A” and a numeric character “4” is operated in a state where the initial screen  40  is displayed on the display unit  12 , the control unit  35  displays the first type character display area  41  where the alphabetic character “A” is input, and the second type character display area  42  where the numeric character “4” is input, on the display unit  12 . Furthermore, the control unit  35  displays one or a plurality of words beginning with “A” (for example, “ARIZONA”, “ALABAMA” and the like) as a predictive conversion candidate(s) in the first type character display area  41 . In a case in which one word is selected from among words of the predictive conversion candidates, the control unit  35  performs displaying by replacing “A” displayed in the first type character display area  41  with the selected word. 
     It should be noted that, in a case in which another second key  222  (for example, a second key  222  assigned with an alphabetic character “R” and a numeric character “0”) is further operated after operating the second key  222  assigned with the alphabetic character “A” and the numeric character “4”, the control unit  35  inputs and displays the alphabetic character “R” after the alphabetic character “A” that is displayed in the first type character display area  41 , and inputs and displays the numeric character “0” after the numeric character “4” that is displayed in the second type character display area  42 . In this case, the control unit  35  displays one or a plurality of words beginning with “AR” (for example, “ARIZONA”, “ARRIVE” and the like) as a predictive conversion candidate(s) in the first type character display area  41 . 
     On the other hand, in a case in which another first key  221  (for example, a first key  222  assigned with an alphabetic character “L”) is operated after operating the second key  222  assigned with the alphabetic character “A” and the numeric character “4”, the control unit  35  cancels displaying the second type character display area  42  from the display unit  12 , and displays only the first type character display area  41  on the display unit  12 . Furthermore, the control unit  35  inputs and displays the alphabetic character “L” after the alphabetic character “A” that is displayed in the first type character display area  41 . In this case, the control unit  35  displays one or a plurality of words beginning with “AL” (for example, “ALABAMA”, “ALASKA” and the like) as a predictive conversion candidate(s) in the first type character display area  41 . 
     Next, descriptions are provided regarding operations of the cellular telephone device  1  of the present embodiment. 
       FIG. 3  is a diagram illustrating a first transition of a display mode of the display unit  12 .  FIG. 4  is a flowchart showing a first operation of the cellular telephone device  1 .  FIG. 5  is a diagram illustrating a second transition of the display mode of the display unit  12 .  FIG. 6  is a flowchart showing a second operation of the cellular telephone device  1 .  FIG. 7  is a diagram illustrating a third transition of the display mode of the display unit  12 .  FIG. 8  is a flowchart showing a third operation of the cellular telephone device  1 .  FIG. 9  is a diagram illustrating a fourth transition of the display mode of the display unit  12 .  FIG. 10  is a flowchart showing a fourth operation of the cellular telephone device  1 . 
     First, descriptions are provided regarding the first transition of the display mode of display unit  12  with reference to  FIG. 3 . 
     In a state where the initial screen  40  on standby for an incoming telephone call is displayed on the display unit  12  (see  FIG. 3A ), in a case in which a second key  222  is depressed, the control unit  35  displays a first type character assigned to the depressed second key  222  in the first type character display area  41 , and displays a second type character assigned to the depressed second key  222  in the second type character display area  42 . For example, in a case in which a second key  222  assigned with an alphabetic character “A” and a numeric character “4” is depressed, as shown in  FIG. 3B , the control unit  35  displays the hiragana character with the pronunciation “a”, which is obtained through Japanese kana conversion of “A”, in the first type character display area  41 , and displays the numeric character “4” in the second type character display area  42 . It should be noted that Japanese character strings with the pronunciation “asu (tomorrow)”, “ano (that)”, “aru (certain)”, “asa (morning)” and “anata (you)” are displayed in the first type character display area  41  in order to perform predictive conversion of the displayed hiragana character with the pronunciation “a”. 
     Subsequently, in a case in which a first key  221  is depressed, the control unit  35  cancels displaying the second type character display area  42  from the display unit  12 , and displays only the first type character display area  41  on the display unit  12 . For example, in a case in which depressing the second key  222  assigned with “A” is followed by depressing the first keys  221  assigned with “K”, “I” and “T”, respectively, and the second key  222  assigned with “A”, as shown in  FIG. 3C , since the first keys  221  are depressed, the control unit  35  cancels displaying the numeric character “4” displayed on the display unit  12  and the second type character display area  42  from the display unit  12 , and displays a hiragana character string with the pronunciation “akita” in the first type character display area  41 . It should be noted that, in a case in which the first keys  221  are depressed more than a predetermined number of times (three times, for example), the control unit  35  may cancel displaying the second type character display area  42  from the display unit  12 , and may display only the first type character display area  41  on the display unit  12 . Moreover, in a case shown in  FIG. 3C , Japanese character strings with the pronunciation “akita (bored)”, “Akita ken (Akita prefecture)”, “Akita” and “Akita shi (Akita city)” are displayed in the first type character display area  41  in order to perform predictive conversion of the hiragana character string with the pronunciation “akita”. 
     Next, descriptions are provided regarding the first operation of the cellular telephone device  1  with reference to  FIG. 4 . 
     Firstly, in Step S 11 , the control unit  35  determines whether a second key  222  assigned with a first type character (nonnumeric character) and a second type character (numeric character) was operated. In a case in which the second key  222  was operated (Yes), the processing advances to Step S 12 . In a case in which the second key  222  was not operated (No), the determination of Step S 11  is performed again. 
     In Step S 12 , the control unit  35  displays the first type character (nonnumeric character) and the second type character (numeric character) assigned to the second key  222 , which was determined to have been operated in Step S 11 , in the first type character display area  41  and the second type character display area  42 , respectively, which are displayed on the display unit  12 . 
     In Step S 13 , the control unit  35  determines whether a first key  221  assigned with only a first type character (nonnumeric character) was operated. In a case in which the first key  221  was operated (Yes), the processing advances to Step S 14 . In a case in which the first key  221  was not operated (No), the determination of Step S 13  is performed again. 
     In Step S 14 , the control unit  35  displays only the first type character (nonnumeric character) on the display unit  12 . In other words, the control unit  35  cancels displaying the second type character display area  42  from the display unit  12 , and displays only the first type character display area  41  on the display unit  12 . 
     Here, the control unit  35  may display only the first type character display area  41  on the display unit  12  on condition that the first keys  221  were operated more than a predetermined number of times. It should be noted that the predetermined number of times may be appropriately set by the user. 
     Next, descriptions are provided regarding the second transition of the display mode of display unit  12  with reference to  FIG. 5 . 
     In a state where the initial screen  40  on standby for an incoming telephone call is displayed on the display unit  12  (see  FIG. 5A ), in a case in which a first key  221  is depressed, the control unit  35  displays a first type character assigned to the depressed first key  221  in the first type character display area  41 , and does not display the second type character display area  42  on the display unit  12 . For example, as shown in  FIG. 5B , in a case in which first keys  221  assigned with “K”, “Y”, “O” and “U”, respectively, are depressed, the control unit  35  displays a hiragana character string with the pronunciation “kyou (today)”, which is obtained through Japanese kana conversion of “KYOU”, in the first type character display area  41 . Japanese character strings with the pronunciation “kyou (today)”, “gyoukai (industry)”, “Kyoto” and “gyoumu (task)” are displayed in the first type character display area  41  in order to perform predictive conversion of the hiragana character string with the pronunciation “kyou”. 
     It should be noted that, in a state where the first type character display area  41  and the second type character display area  42  are displayed on the display unit  12 , in a case in which a first key  221  is depressed, the control unit  35  can display a first type character assigned to the depressed first key  221  in the first type character display area  41 , and cancel displaying the second type character display area  42  from the display unit  12 . 
     Next, descriptions are provided regarding the second operation of the cellular telephone device  1  with reference to  FIG. 6 . 
     Firstly, in Step S 21 , the control unit  35  determines whether a first key  221  assigned with only a first type character (nonnumeric character) was operated. In a case in which the first key  221  was operated (Yes), the processing advances to Step S 22 . In a case in which the first key  221  was not operated (No), determination in Step S 21  is performed again. 
     In Step S 22 , the control unit  35  displays only the first type character (nonnumeric character) on the display unit  12 . In other words, in a state where the initial screen  40  is displayed on the display unit  12 , in a case in which the first key  221  is operated, the control unit  35  displays only the first type character display area  41  on the display unit  12 , and does not display the second type character display area  42  on the display unit  12 . Moreover, in a state where the first type character display area  41  and the second type character display area  42  are displayed on the display unit  12 , in a case in which first key  221  is operated, the control unit  35  cancels displaying the second type character display area  42  from the display unit  12 , and displays only the first type character display area  41  on the display unit  12 . 
     Here, it is possible for the control unit  35  to display only the first type character display area  41  on the display unit  12  on condition that the first keys  221  were operated more than a predetermined number of times. It should be noted that the predetermined number of times may be appropriately set by the user. 
     Next, descriptions are provided regarding the third transition of the display mode of display unit  12  with reference to  FIG. 7 . 
     In a state where the initial screen  40  on standby for an incoming telephone call is displayed on the display unit  12  (see  FIG. 7A ), in a case in which a second key  222  is depressed, the control unit  35  displays a first type character assigned to the depressed second key  222  in the first type character display area  41 , and displays a second type character assigned to the depressed second key  222  in the second type character display area  42 . For example, as shown in  FIG. 7B , in a case in which second keys  222  assigned with “R, 0”, “Q, 1”, “W, 2”, “E, 3”, “A, 4”, “S, 5” and “D, 6”, respectively, were depressed, the control unit  35  displays a mixed character string of kana and alphabetic characters represented alphabetically as “r ku e a s d”, which is obtained through Japanese kana conversion of an alphabetic character string “RQWEASD”, in the first type character display area  41 , and displays a numeric character string “0123456” in the second type character display area  42 . 
     In a case in which a character(s) such as the mixed character string “r ku e a s d”, for which Japanese kana conversion cannot be performed, is displayed in the first type character display area  41 , the control unit  35  cancels displaying the first type character display area  41  and the first type characters (nonnumeric characters), for which Japanese kana conversion cannot be performed, and displays only the second type character display area  42  on the display unit  12 . For example, as shown in  FIG. 7C , the control unit  35  displays the numeric character string “0123456” in the second type character display area  42 . 
     Next, descriptions are provided regarding the third operation of the cellular telephone device  1  with reference to  FIG. 8 . 
     Firstly, in Step S 31 , the control unit  35  determines whether a second key  222  assigned with a first type character (nonnumeric character) and a second type character (numeric character) was operated. In a case in which the second key  222  was operated (Yes), the processing advances to Step S 32 . In a case in which the second key  222  was not operated (No), the determination of Step S 31  is performed again. 
     In Step S 32 , the control unit  35  displays the first type character (nonnumeric character) and the second type character (numeric character) assigned to the second key  222 , which was determined to have been operated in Step S 31 , in the first type character display area  41  and the second type character display area  42 , respectively, which are displayed on the display unit  12 . 
     In Step S 33 , the control unit  35  determines whether a character that cannot be recognized as a character string (an alphabetic character that cannot be converted into a Japanese character) is displayed in the first type character display area  41 . In other words, the control unit  35  determines whether a first type character (nonnumeric character) that cannot be converted into a Japanese character is displayed in the first type character display area  41 . In a case in which the first type character (nonnumeric character) that cannot be converted into a Japanese character is displayed (Yes), the processing advances in Step S 34 . In a case in which the first type character (nonnumeric character) that cannot be converted into a Japanese character is not displayed (No), the determination of Step S 33  is performed again. 
     In Step S 14 , the control unit  35  displays only the second type characters (numeric characters) on the display unit  12 . In other words, the control unit  35  cancels displaying the first type character display area  41  from the display unit  12 , and displays only the second type character display area  42  on the display unit  12 . 
     Next, descriptions are provided regarding the fourth transition of the display mode of display unit  12  with reference to  FIG. 9 . 
     In a state where the initial screen  40  on standby for an incoming telephone call is displayed on the display unit  12  (see  FIG. 9A ), in a case in which a second key  222  is depressed, the control unit  35  displays a first type character assigned to the depressed second key  222  in the first type character display area  41 , and displays a second type character assigned to the depressed second key  222  in the second type character display area  42 . 
     For example, as shown in  FIG. 9B , in a case in which predetermined second keys  222  are depressed, and Japanese kana conversion is performed, the control unit  35  displays a hiragana character string with the pronunciation “sa sa za wa” in the first type character display area  41 , and displays a numeric character string “54547424” in the second type character display area  42 . It should be noted that a kanji character string with the pronunciation “sasa zawa” and a katakana character string with the pronunciation “sa sa za wa” are displayed in the first type character display area  41  in order to perform predictive conversion of the hiragana character string with the pronunciation “sa sa za wa”. 
     Subsequently, in a case in which the second keys  222  are consecutively depressed more than a predetermined number of times, and as a result of which the number of digits of the second type characters (numeric characters) displayed in the second type character display area  42  exceeds a predetermined number of digits, the control unit  35  cancels displaying the second type character display area  42  from the display unit  12 , and displays only the first type character display area  41  on the display unit  12 . It should be noted that the predetermined number of digits may be appropriately set by the user. 
     For example, in a case in which the predetermined number of digits is 11 digits, and second keys  222  assigned with “S, 5”, “A, 4”, “W, 2”, “A, 4” and “E, 3”, respectively, are further depressed, as shown in  FIG. 9C , since the numeric characters displayed in the second type character display area  42  are 13 digits, the control unit  35  displays the first type character display area  41  including a hiragana character string with the pronunciation “sa sa za wa sa wa e” on the display unit  12 , and cancels displaying the second type character display area  42  from the display unit  12 . 
     Next, descriptions are provided regarding the fourth operation of the cellular telephone device  1  with reference to  FIG. 10 . 
     Firstly, in Step S 41 , the control unit  35  determines whether a second key  222  assigned with a first type character (nonnumeric character) and a second type character (numeric character) was operated. In a case in which the second key  222  was operated (Yes), the processing advances to Step S 42 . In a case in which the second key  222  was not operated (No), the determination of Step S 41  is performed again. 
     In Step S 42 , the control unit  35  displays the first type character (nonnumeric character) and the second type character (numeric character) assigned to the second key  222 , which was determined to have been operated in Step S 41 , in the first type character display area  41  and the second type character display area  42 , respectively, which are displayed on the display unit  12 . 
     In Step S 43 , the control unit  35  determines whether the number of operations has exceeded a predetermined number of digits. In other words, the control unit  35  determines whether the number of the second type characters (numeric characters) displayed in the second type character display area  42  exceeds a predetermined number of digits as a result of depressing the second keys  222  more than a predetermined number of times. In a case in which the number of operations has exceeded the predetermined number of digits (Yes), the processing advances to Step S 44 . In a case in which the number of operations has not exceeded the predetermined number of digits (No), determination in Step S 43  is performed again. 
     In Step S 44 , the control unit  35  displays the first type characters (nonnumeric characters) on the display unit  12 . In other words, the control unit  35  cancels displaying the second type character display area  42  from the display unit  12 , and displays only the first type character display area  41  on the display unit  12 . 
     Second Embodiment 
     With reference to  FIG. 11 , descriptions are provided regarding a basic structure of a cellular telephone device as a second embodiment of the portable electronic device of the present invention. 
       FIG. 11  is an external perspective view of the cellular telephone device as the second embodiment of the portable electronic device. 
     A cellular telephone device  2  includes a first body  10  and a second body  20  that are connected so as to be openable and closable. 
     A display unit  12  and a first operation unit  50  are disposed on a front face  11  of the first body  10 . 
     The display unit  12  displays at least one of first type characters and second type characters in accordance with an operation of the first operation unit  50  or a second operation unit  51  that will be described later. In addition, the display unit  12  displays various types of information (character information, numeric character information, and image information) such as a telephone numbers, email addresses of communication parties, and email content. 
     The first operation unit  50  is configured to include first keys  501  assigned with the first type characters and the second type characters. Furthermore, the first operation unit  50  includes: function setting operation keys  502  for operating various functions such as respective setting functions, dictionary functions, email functions and the like; and a selection operation key  503  for executing selection in various operations, scrolling and the like. The first operation unit  50  is exposed to the outside of the cellular telephone device  2  in both the closed state and the opened state of the first body  10  and the second body  20 . 
     Moreover, a microphone  13  and a receiver  14  are disposed on the front face  11  of the first body  10 . In addition, a speaker  15  (see  FIG. 12 ) is disposed on a side face of the first body  10 . 
     The second operation unit  51  is disposed on a front face  21  of the second body  20 . The front face  21  of the second body  20  opposes a rear face of the first body  10  (a face opposite to the front face  11  of the first body  10 ). The second operation unit  51  is covered by the first body  10  when the first body  10  and second body  20  are in a closed state, and is exposed to the outside when the first body  10  and second body  20  are in an opened state. Therefore, the second operation unit  51  is operational when the first body  10  and the second body  20  slide in relation to each other to transition to the opened state. The second operation unit  51  is configured to include second keys  511  assigned with the first type characters but not second type characters, and third keys  512  assigned with the first type characters and the second type characters. 
     Next, descriptions are provided regarding a functional configuration of the cellular telephone device  2  with reference to  FIG. 12 . 
       FIG. 12  is a block diagram showing a functional configuration of the cellular telephone device  2 . The cellular telephone device  2  includes the first operation unit  50 , the second operation unit  51 , the microphone  13 , the display unit  12 , the receiver  14 , the speaker  15 , a driver IC  30 , a communication unit  31 , an image processing unit  32 , a sound processing unit  33 , a storage unit  34 , and a control unit  35 . 
     In a state where an initial screen is displayed on the display unit  12 , in a case in which any one of the first keys  501  is operated, the control unit  35  displays a second type character assigned to the operated first key  501  on the display unit  12 , and in a case in which any one of the second keys  511  or the third keys  512  is operated, the control unit  35  displays a first type character assigned to the second keys  511  or the third keys  512  thus operated on the display unit  12 . 
     Here, the first type characters are nonnumeric characters. Moreover, the second type characters are numeric characters. In addition, the numeric characters as the second type characters include, for example, symbols utilized for an outgoing telephone call such as “# (hash mark)”, “* (asterisk)”, “- (hyphen)”, “P (pause)” and the like. 
     Furthermore, the control unit  35  controls the entirety of the cellular telephone device  2 , and performs predetermined control of the display unit  12 , the communication unit  31 , the image processing unit  32 , and the sound processing unit  33 . 
     Since configurations of the driver IC  30 , the communication unit  31 , the image processing unit  32 , the sound processing unit  33  and the storage unit  34  are similar to the configurations described with reference to  FIG. 2 , a description thereof is omitted. 
     As described above, in the first operation unit  50 , in a case in which any one of the first keys  501  assigned with the first type characters (nonnumeric characters) and the second type characters (numeric characters) is operated, the cellular telephone device  2  displays a second type character corresponding to the first key  501  on the display unit  12 . Moreover, in the second operation unit  51 , in a case in which any one of the second keys  511  assigned with only the first type characters or any one of the third keys  512  assigned with the first type characters and the second type characters is operated, the cellular telephone device  2  displays a first type character corresponding to the second key  511  or the third key  512  on the display unit  12 . Therefore, the cellular telephone device  2  can make a display that reflects the user&#39;s intention.