Abstract:
According to one aspect of the invention, there is provided a mobile apparatus including: a plurality of input sections each configured to display at least one image that corresponds to an input value assigned thereto; a plurality of label areas provided correspondingly to the plurality of input sections, each of the label areas labeled with at least one characters associated with the input value that is assigned to a corresponding one of the plurality of input sections; a photosensor configured to measure ambient illuminance; and a display controller configured to control turn-off and turn-on of image-display at the plurality of input sections based on the ambient illuminance.

Description:
The entire disclosure of Japanese Patent Application No. 2008-187750 filed on Jul. 18, 2008, including specification, claims, drawings and abstract is incorporated herein by reference in its entirety. 
     BACKGROUND 
     1. Field of the Invention 
     One aspect of the present invention relates to a mobile apparatus including input sections capable of displaying images. 
     2. Description of the Related Art 
     In general, a mobile apparatus, such as a mobile phone or a mobile information terminal, includes a main display that displays text information or image information, and an input device that has input sections, such as a plurality of push-button switches. 
     Typically, the push-button switches are configured such that the input values individually assigned to the push-button switches can be identified by labels, such as engraved marks or prints, on the keytops thereof. 
     To further increase visual effect, there is a technology which provides a light-emitting diode in each push-button switch. As the switch is switched, the light-emitting diode is switched between an emission state and a non-emission state or changes colors. 
     A mobile apparatus described in JP-A-2003-303526 includes push-button switches having keytops without prefixed labels, but images can be displayed on the keytops. 
     In the mobile apparatus, the images are displayed on the keytops of the push-button switches, such that the input values assigned to the push-button switches can be identified. That is, in order to identify the input values assigned to the push-button switches, it is necessary to continuously display the images on the keytops. 
     In the mobile apparatus, however, the images are displayed on the keytops, and accordingly power is constantly consumed. 
     The mobile apparatus includes a battery serving as a power supply section, and the battery has limited discharge capacity. For this reason, in the mobile apparatus that continuously displays the images on the keytops, the battery is discharged within a short time, and an available time is shortened. 
     SUMMARY 
     According to one aspect of the invention, there is provided a mobile apparatus including: a plurality of input sections each configured to display at least one image that corresponds to an input value assigned thereto; a plurality of label areas provided correspondingly to the plurality of input sections, each of the label areas labeled with at least one characters associated with the input value that is assigned to a corresponding one of the plurality of input sections; a photosensor configured to measure ambient illuminance; and a display controller configured to control turn-off and turn-on of image-display at the plurality of input sections based on the ambient illuminance. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Embodiment may be described in detail with reference to the accompanying drawings, in which: 
         FIGS. 1A to 1D  are exemplary exterior views of a foldable mobile phone which is an example of a mobile apparatus according to the invention; 
         FIG. 2  shows an exemplary change in state of the foldable mobile phone; 
         FIG. 3  is an exemplary partial sectional view of a display function-equipped operation input section in the foldable mobile phone; 
         FIG. 4  is an exemplary block diagram showing the foldable mobile phone; 
         FIG. 5  is an exemplary front view showing states where the foldable mobile phone is unfolded, wherein examples of a display state of the display function-equipped operation input section are shown; 
         FIG. 6  is an exemplary flowchart showing display control of the display function-equipped operation input section in the foldable mobile phone; 
         FIG. 7  is a flowchart showing another example of display control of the display function-equipped operation input section in the foldable mobile phone; 
         FIG. 8  is an exemplary front view showing states where the foldable mobile phone is unfolded, wherein examples of a display state of the display function-equipped operation input section are shown; 
         FIG. 9  is a flowchart showing yet another example of display control of the display function-equipped operation input section in the foldable mobile phone; 
         FIG. 10  is a flowchart showing yet another example of display control of the display function-equipped operation input section in the foldable mobile phone; 
         FIG. 11  is a flowchart showing yet another example of display control of the display function-equipped operation input section in the foldable mobile phone; and 
         FIG. 12  is a flowchart showing yet another example of display control of the display function-equipped operation input section in the foldable mobile phone. 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     A mobile apparatus according to an embodiment of the invention will be described with reference to  FIGS. 1A to 12 .  FIGS. 1A to 1D  are exterior views of a foldable mobile phone which is an example of the mobile apparatus according to the invention. Specifically,  FIG. 1A  is a front view showing a state where the mobile phone is unfolded, and  FIG. 1B  is a side view showing a state where the foldable mobile phone which is an example of the mobile apparatus according to the invention is unfolded.  FIG. 1C  is a front view showing a state where the mobile phone is folded, and  FIG. 1D  is a side view showing a state where the foldable mobile phone which is an example of the mobile apparatus according to the invention is folded. 
     As shown in  FIGS. 1A to 1D , the mobile phone  1  includes a hinge  11 , a first casing  12 , and a second casing  13 . The first casing  12  and the second casing  13  are hinged by the hinge  11  at its central portion. The mobile phone  1  is formed to be foldable in directions of arrows X and Y through the hinge  11 . As shown in  FIGS. 1C and 1D , the mobile phone  1  is folded by rotating the first casing  12  and the second casing  13  around the hinge  11 . In this case, the first casing  12  and the second casing  13  substantially overlap each other. 
     At a front of the first casing  12 , a display function-equipped operation input section  15 , label areas  16 , and a microphone  18  are provided. 
     The display function-equipped operation input section  15  has a plurality of keytops  19  (input sections) without prefixed picture thereon, but arbitrary characters or symbols can be displayed on the keytops  19 . The display function-equipped operation input section  15  accepts an operation input of the mobile phone  1 . Each keytop  19  is assigned with a plurality of input values. Each time an operation is performed, each of the keytops  19  is sequentially switched between the input values. Thus, a plurality of input values can be input for each keytop  19 . In this case, an image to be displayed on the keytop  19  may include all available input values, or may be changed according to input values each time an operation is performed. 
     If the mobile phone  1  is unfolded in the direction of the arrow X, a rotation axis Rx is located upward, and images are displayed on the keytops  19  in the display function-equipped operation input section  15 . In the display function-equipped operation input section  15 , at least one of character types, such as numerals from “0” to “9”, alphabetic characters from “a” to “z”, alphabetic characters from “A” to “Z”, and symbols, such as “@”, “/”, and the like, and an arbitrary image can be displayed. As occasion demands, the display function-equipped input section  15  may be in a non-display state. The keytops  19  are individually assigned to a send key  20 , an end key  21 , a power key  22 , a character type selection key  23 , and a character input operation key  24 . If one of the send key  20 , the end key  21 , the power key  22 , the character type selection key  23 , and the character input operation key  24  is pressed, an input value corresponding to the key is input to the mobile phone  1 . 
     The label areas  16  are provided near the keytops  19 . The label areas  16  are respectively provided to a corresponding keytop  19 . The label areas  16  have characters or symbols engraved or printed on the first casing  12 . Specifically, in each of the label areas  16 , at least one of character types, such as the numerals from “0” to “9”, alphabetic characters from “a” to “z”, alphabetic characters from “A” to “Z”, and symbols, such as “@”, “/”, and the like, is labeled. Each of the label areas  16  is labeled associated with at least one of the input values of a corresponding keytop  19 . For example, when the input values assigned to a keytop  19  is “1”, alphabetic characters “a” to “c”, and alphabetic characters “A” to “C”, at least one of “1”, alphabetic characters “abc”, and alphabetic characters “ABC” is labeled in the label area  16 . The label areas  16  may be a plate-shaped member that covers the face of the first casing  12 . 
     The microphone  18  is provided at the other end of the first casing  12  opposite to one end of the first casing  12  at which the hinge  11  is formed. The microphone  18  collects a user&#39;s voice during calling, and converts the collected voice into an electrical signal. 
     A battery pack (not shown) is provided at a rear of the first casing  12 . If the power key  22  is operated, the mobile phone  1  starts to be operable by power supplied from the battery pack. 
     At a front of the second casing  13 , a main display device  27 , a speaker  28 , and a photosensor  29  are provided. 
     The main display device  27  is formed by a Liquid Crystal Display (LCD), an organic Electro Luminescence Display (EL display), an Inorganic Electro Luminescence Display (inorganic EL display), a Surface-conduction Electron-emitter Display (SED), or the like. 
     The main display device  27  displays a reception state of an electric wave, a residual battery charge, the name or telephone number of a person to call registered in the directory, a transmission history, the content of an electronic mail, a simplified homepage, and contents received from an external contents server (not shown). 
     The speaker  28  is provided at the other end of the second casing  13  opposite to one end of the second casing  13  at which the hinge  11  is formed. The speaker  28  outputs a voice from a received signal which is acquired from the person to call during calling. A user can perform a voice call by using the microphone  18  and the speaker  28  of the first casing  12 . 
     A speaker (not shown), other than the speaker  28 , serving as a speech output section, is provided at a position of the mobile phone  1 . 
     The photosensor  29  is an illuminance sensor which detects illuminance of an environment to which the mobile phone  1  is exposed. The photosensor  29  is disposed at a position sufficiently away from the main display device  27  on the front of the second casing  13  so as to detect illuminance without being disturbed by light emitted from the main display device  27 . Magnetic measuring sections  30   a ,  30   b , and  30   c  are provided at positions inside the first casing  12  and the second casing  13  to detect the folded/unfolded state of the mobile phone  1 . 
       FIG. 2  is a diagram showing states that the foldable mobile phone which is an example of the mobile apparatus according to the invention can take. Specifically, in  FIG. 2 , section (A) is a diagram showing a state where the foldable mobile phone is unfolded, like the state of  FIG. 1A , and section (B) is a diagram showing a state where the first casing  12  and the second casing  13  are rotated around the hinge  11  from the state shown in  FIG. 2 , section (A) and folded. Section (C) is a diagram showing a state where the mobile phone  1  is unfolded in the direction of the arrow Y from the folded state shown in  FIG. 2 , section (B) through the hinge  11 . In this case, in the display function-equipped operation input section  15 , a rotation axis Ry is located upward, and the images are displayed on the keytops  19 . Section (D) is a diagram showing a state where no images are displayed on the keytops  19  of the display function-equipped operation input section  15  in the state of section (A). Similarly, section (E) is a diagram showing a state where no images are displayed on the keytops  19  of the display function-equipped operation input section  15  in the state of section (C). 
     A case in which the mobile phone  1  is unfolded in the direction of the arrow X through the hinge  11  ( FIG. 2 , section (A)) is called a “vertically unfolded state”, and a case in which the mobile phone  1  is unfolded in the direction of the arrow Y through the hinge  11  ( FIG. 2 , section (C)) is called a “horizontally unfolded state”. Based on the detection results of the magnetic measuring sections  30   a ,  30   b , and  30   c , it is determined whether the mobile phone  1  is in the vertically unfolded state, the horizontally unfolded state, or the folded state. 
       FIG. 3  is a partial sectional view of the display function-equipped input section of the foldable mobile phone which is an example of the mobile apparatus according to the invention. As shown in  FIG. 3 , the display function-equipped operation input section  15  includes a plurality of keytops  19 , a switch circuit board  33 , and an input section display device  34 . 
     Each of the keytops  19  is formed of a transparent member, through which the input section display device  34  disposed at the rear of the keytop  19  can be viewed. At a side of the keytop  19 , a protrusion  35  is formed. The protrusion  35  is formed at a position where there is no influence on observation of an image to be displayed on the input section display device  34 . 
     The protrusion  35  is sandwiched between the first casing  12  and the switch circuit board  33 , and thus the keytop  19  is held. 
     The switch circuit board  33  has a plurality of contacts  36  corresponding to the keytops  19 , wirings (not shown) for connecting the contacts  36 , and a switch circuit having an insulating layer. The switch circuit board  33  has openings  37 , through which display light L from the input section display device  34  transmits, directly below the keytops  19 . The user views images displayed on the input section display device  34  through the openings  37  of the switch circuit board  33  and the keytops  19 . 
     The images displayed on the input section display device  34  and viewed by the user through the keytops  19  are called “keytop display images”. 
     The input section display device  34  is disposed at the rear of the switch circuit board  33 . The input section display device  34  is formed by a display that is thin, lightweight, and realizes low power consumption. Specifically, the input section display device  34  is a Liquid Crystal Display (LCD), an Electro Luminescence Display (organic EL display), an Inorganic Electro Luminescence Display (inorganic EL display), a Surface-conduction Electron-emitter Display (SED), or the like. 
     The display function-equipped operation input section  15  may include the input section display device  34  and a touch panel through which an image displayed on the input section display device  34  transmits. 
       FIG. 4  is a block diagram showing the foldable mobile phone which is an example of the mobile apparatus according to the invention. As shown in  FIG. 4 , the mobile phone  1  includes a main controller  40 , a power supply circuit section  41 , an input controller  42 , a display controller  43 , a memory  44 , a audio controller  45 , a communication controller  46 , a timer  47 , an illuminance measuring section  48 , and magnetic measuring sections  30   a ,  30   b , and  30   c , all of which are communicably connected to each other through a bus. 
     The main controller  40  includes a Central Processing Unit (CPU). The main controller  40  generates various control signals and supplies the control signals to the individual sections to thereby overall control the mobile phone  1 . The main controller  40  performs, for example, an input control process for the input controller  42 , and various arithmetic processes or control processes. 
     The power key  22  and the battery pack are connected to the power supply circuit section  41 . If the user presses the power key  22 , the power key  22  outputs an operation signal. If the operation signal is input, the power supply circuit section  41  generates a signal indicative of the input of the operation signal and outputs the signal to the main controller  40 , and simultaneously switches the mobile phone  1  between an operation state and a stop state. If the mobile phone  1  is in the operation state, the power supply circuit section  41  supplies power to the individual sections from the battery pack. 
     The input controller  42  is connected to the display function-equipped operation input section  15 . If a keytop  19  of the display function-equipped operation input section  15  is pressed, an operation signal corresponding to the pressed keytop  19  is generated and output to the main controller  40 . 
     The display controller  43  is connected to the main display device  27  and the input section display device  34 . The display controller  43  invalidates or validates display of the main display device  27  and the input section display device  34  under the control of the main controller  40 . The display controller  43  also controls the main display device  27  to display document data or image data under the control of the main controller  40 . The display controller  43  controls the input section display device  34  to display a keytop display image under the control of the main controller  40 . 
     The audio controller  45  is connected to the microphone  18 . The audio controller  45  converts an analog speech signal output from the microphone  18  into a digital speech signal, and outputs the digital speech signal to the communication controller  46  under the control of the main controller  40 . The audio controller  45  also converts a digital speech signal from among received signals output from the communication controller  46  into an analog speech signal, and outputs the analog speech signal to the speaker  28  under the control of the main controller  40 . The speaker  28  converts the analog speech signal and outputs a voice. 
     The communication controller  46  performs spectrum de-spreading on an electric wave received from a base station through an antenna  51  to restore a received signal under the control of the main controller  40 . The received signal is input to the audio controller  45  and output from the speaker  28 , is input to the display controller  43  and displayed on the main display device  27 , or is recorded in the memory  44  according to a command from the main controller  40 . The communication controller  46  also acquires the digital speech signal output from the audio controller  45 , the operation signal output from the input controller  42 , and the information signal stored in the memory  44  under the control of the main controller  40 , performs spectrum spreading on the signals, and transmits the signals from the antenna  51  to the base station. 
     With respect to the process to be performed by the main controller  40 , the memory  44  stores processing programs or information signals required for the process. The memory  44  includes a Read Only Memory (ROM) or hard disk, a nonvolatile memory, a Random Access Memory (RAM) which temporarily stores data to be used when the main controller  40  performs the process, and the like. 
     The timer  47  generates a reference time signal which is referred to by the individual sections of the mobile phone  1 . The photosensor  29  is connected to the illuminance measuring section  48 . When the illuminance detected by the photosensor  29  is bright so as to be equal to more than a threshold value, the illuminance measuring section  48  outputs a display stop signal of the input section display device  34  to the display controller  43 . When the illuminance detected by the photosensor  29  is dark so as to be less than the threshold value, the illuminance measuring section  48  outputs a display start signal of the input section display device  34  to the display controller  43 . 
     The illuminance measuring section  48  may convert the illuminance detected by the photosensor  29  into stepwise illuminance level signals corresponding to a plurality of threshold values and may output the illumination level signals. In this case, the display controller  43  can control the brightness of the input section display device  34  in a stepwise manner according to the illuminance level signals output from the illuminance measuring section  48 . Specifically, when the illuminance of an environment to which the mobile phone  1  is exposed is bright so as to be equal to or more than the threshold value, the display controller  43  turns off the input section display device  34 . When the illuminance of the environment to which the mobile phone  1  is exposed is dark so as to be less than the threshold value, as the illuminance of the environment to which the mobile phone  1  is exposed is darker, the display controller  43  turns on the input section display device  34  with dark brightness. As the illuminance of the environment to which the mobile phone  1  is exposed is brighter, the input section display device  34  is lighted up brighter. 
     The magnetic measuring sections  30   a ,  30   b , and  30   c  determine based on a combination of magnetic detection and non-magnetic detection whether the mobile phone  1  is unfolded in the X direction, is unfolded in the Y direction, or the closed direction, and outputs the determination result to the main controller  40 . 
     Next, a display operation of the display function-equipped operation input section  15  of the mobile phone  1  according to this embodiment will be described. Here, a keytop display image to be displayed in the display function-equipped operation input section  15  is illustrated. 
       FIG. 5  shows front views of the foldable mobile phone which is an example of the mobile apparatus according to the invention is unfolded. In  FIG. 5 , sections (A) to (C) are diagrams showing an example of a display state of the display function-equipped operation input section. 
     As shown in section (A), for example, numerals from “0” to “9”, alphabetic characters from “a” to “z”, alphabetic characters from “A” to “Z”, or symbols, such as “@” and the like, are labeled in the label areas  16  of the mobile phone  1 . In contrast, alphabetic characters from “a” to “z” are displayed on the keytops  19  as the keytop display images. 
     As shown in section (B), for example, numerals from “0” to “9”, alphabetic characters from “a” to “z”, alphabetic characters from “A” to “Z”, or symbols, such as “@” and the like, are labeled in the label area  16  of the mobile phone  1 . In contrast, numerals from “0” to “9” and symbols, such as “.”, “.”, and the like, are displayed on the keytops  19  as the keytop display images. 
     As shown in section (C), for example, numerals from “0” to “9”, alphabetic characters from “a” to “z”, alphabetic characters from “A” to “Z”, or symbols, such as “@” and the like, are labeled in the label areas  16  of the mobile phone  1 . In contrast, alphabetic characters from “A” to “Z” are displayed on the keytops  19  as the keytop display images. In  FIG. 5 , sections (A) to (C), if the character type selection key  23  is pressed, an input character type when a keytop  19  or a label area  16  is pressed varies. For example, in the state of  FIG. 5 , section (A), an alphabet (lower case) input mode is performed. In this state, if the character type selection key  23  is pressed once, the state of  FIG. 5 , section (B) arises, and a numeral input mode is performed. In the state of  FIG. 5 , section (B), if the character type selection key  23  is pressed again, the state of  FIG. 5 , section (C) arises and an alphabet (uppercase) input mode is performed. In the state of  FIG. 5 , section (C), if the character type selection key  23  is pressed again, the state of  FIG. 5 , section (A) is returned and the alphabet (lower case) input mode is performed. 
       FIG. 6  is a flowchart showing display control of the display function-equipped operation input section in the foldable mobile phone which is an example of the mobile apparatus according to the invention. 
     As shown in  FIG. 6 , when the mobile phone  1  is supplied with power and activated, first, in Step S 1 , the illuminance measuring section  48  compares the illuminance detected by the photosensor  29  with the threshold value. When the illuminance detected by the photosensor  29  is equal to or more than the threshold value, the illuminance measuring section  48  determines that the environment to which the mobile phone  1  is exposed is bright and outputs the display stop signal. Next, the process progresses to Step S 2 . Otherwise, the illuminance measuring section  48  determines that the environment to which the mobile phone  1  is exposed is dark and outputs the display start signal. Next, the process progresses to Step S 3 . 
     Next, in Step S 2 , the main controller  40  inputs the display stop signal output from the illuminance measuring section  48  to the display controller  43 . The display controller  43  turns off the input section display device  34  or maintains a turning-off state of the input section display device  34  based on the display stop signal, and then the process returns to Step S 1 . In this case, since the environment to which the mobile phone  1  is exposed is bright, as shown in  FIG. 2 , section (D), the user can recognize the characters or symbols assigned to the keytops  19  from the indication of the label areas  16 . Therefore, when the environment to which the mobile phone  1  is exposed is bright, the mobile phone  1  controls the input section display device  34  so as not to emit light, and thus the amount of power consumption of the battery pack can be suppressed. 
     Next, in Step S 3 , the main controller  40  inputs the display start signal output from the illuminance measuring section  48  to the display controller  43 . The display controller  43  turns on the input section display device  34  or maintains a turning-on state of the input section display device  34  based on the display start signal, and then the process returns to Step S 1 . In this case, since the environment to which the mobile phone  1  is exposed is dark, as shown in  FIG. 2 , section (A), the user can recognize the characters or symbols assigned to the keytops  19  from the keytop display images. In addition, as shown in  FIG. 5 , sections (A) to (C), the display controller  43  may control the keytop display images to be displayed to correspond to character types to be input. 
     That is, the mobile phone  1  turns off the input section display device  34  when the environment to which the mobile phone  1  is exposed is bright, and turns on the input section display device  34  when the environment to which the mobile phone  1  is exposed is dark. The user can recognize the characters or symbols assigned to the keytops  19  from display of the label areas  16  when the environment to which the mobile phone  1  is exposed is bright, and recognize the characters or symbols assigned to the keytops  19  from the keytop display images when the environment to which the mobile phone  1  is exposed is dark. Therefore, the mobile phone  1  appropriately switches the turning-on state and the turning-off state of the input section display device  34  according to the use environment thereof, thereby suppressing power consumption. 
       FIG. 7  is a flowchart showing another example of display control of the display function-equipped operation input section in the foldable mobile phone which is an example of the mobile apparatus according to the invention. As shown in  FIG. 7 , the mobile phone  1  does not immediately switch the turning-on state and the turning-off state of the input section display device  34  according to the use environment thereof, but it is not until the user starts to operate the mobile phone  1  that the mobile phone  1  turns on the input section display device  34 . In addition, if a threshold time elapses after the input section display device  34  is turned on until the user next operates the mobile phone  1 , the mobile phone  1  turns off the input section display device  34 . 
     If the mobile phone  1  is supplied with power and activated, first, in Step S 11 , the illuminance measuring section  48  compares the illuminance detected by the photosensor  29  with the threshold value. When the illuminance detected by the photosensor  29  is equal to or more than the threshold value, the illuminance measuring section  48  determines that the environment to which the mobile phone  1  is exposed is bright and outputs the display stop signal. Next, the process progresses to Step S 12 . Otherwise, the illuminance measuring section  48  determines that the environment to which the mobile phone  1  is exposed is dark and outputs the display start signal. Next, the process progresses to Step S 13 . 
     Next, in Step S 12 , the main controller  40  inputs the display stop signal output from the illuminance measuring section  48  to the display controller  43 . The display controller  43  turns off the input section display device  34  or maintains the turning-off state of the input section display device  34  based on the display stop signal, and then the process returns to Step S 11 . In this case, since the environment to which the mobile phone  1  is exposed is bright, as shown in  FIG. 2 , section (D), the user can recognize the characters or symbols assigned to the keytops  19  from the label areas  16 . Therefore, when the environment to which the mobile phone  1  is exposed is bright, the mobile phone  1  controls the input section display device  34  so as not to emit light, thereby suppressing the amount of power consumption of the battery pack. 
     Next, in Step S 13 , the main controller  40  determines whether or not an arbitrary keytop  19  of the display function-equipped operation input section  15  is operated. Specifically, if an arbitrary keytop  19  of the display function-equipped operation input section  15  is operated, the input controller  42  outputs an arbitrary operation signal. The main controller  40  monitors presence/absence of the input of the arbitrary operation signal. When an arbitrary operation signal is input, the main controller  40  determines that an arbitrary keytop  19  of the display function-equipped operation input section  15  is operated, and then the process progresses to Step S 14 . Otherwise, the main controller  40  determines that an arbitrary keytop  19  of the display function-equipped operation input section  15  is not operated, and then the process returns to Step S 11 . 
     Next, in Step S 14 , the main controller  40  inputs the display start signal output from the illuminance measuring section  48  to the display controller  43 . The display controller  43  turns on the input section display device  34  or maintains the turning-on state of the input section display device  34  based on the display start signal. In this case, since the environment to which the mobile phone  1  is exposed is dark, as shown in  FIG. 2 , section (A), the user can recognize the characters or symbols assigned to the keytops  19  from the keytop display images. In addition, as shown in  FIG. 5 , sections (A) to (C), the display controller  43  may control the keytop display images to be displayed to correspond to character types to be input. 
     Next, in Step S 15 , the input controller  42  compares a threshold time with a time elapsed after an arbitrary keytop  19  of the display function-equipped operation input section  15 is operated. Specifically, the input controller  42  compares a threshold time with a time elapsed after an arbitrary operation signal is output. When the time elapsed after the arbitrary operation signal is output is equal to or more than the threshold time, the input controller  42  determines that no operation of the mobile phone  1  by the user is performed within the threshold time and outputs an operation stop signal. Next, the process progresses to Step S 17 . Otherwise, the input controller  42  determines that an operation of the mobile phone  1  by the user is performed within the threshold time and outputs an operation continuation signal. Next, the process progresses to Step S 16 . 
     Next, in Step S 16 , the illuminance measuring section  48  compares the illuminance detected by the photosensor  29  with the threshold value. When the illuminance detected by the photosensor  29  is equal to or more than the threshold value, the illuminance measuring section  48  determines that the environment to which the mobile phone  1  is exposed is bright and outputs the display stop signal. Next, the process progresses to Step S 17 . Otherwise, the illuminance measuring section  48  determines that the environment to which the mobile phone  1  is exposed is dark and outputs the display start signal. Next, the process progresses to Step S 15 . 
     Next, in Step S 17 , the main controller  40  inputs the display stop signal output from the illuminance measuring section  48  to the display controller  43 . The display controller  43  turns off the input section display device  34  based on the display stop signal, and then the process returns to Step S 11 . In this case, even if the environment to which the mobile phone  1  is exposed is dark, no operation of the mobile phone  1  by the user is performed within the threshold time. For this reason, it is determined that the need for perceiving the characters or symbols assigned to the keytops  19  is reduced. Therefore, even if the environment to which the mobile phone  1  is exposed is dark, the mobile phone  1  controls the input section display device  34  so as not to emit light, thereby suppressing the amount of power consumption of the battery pack. 
     That is, when the environment to which the mobile phone  1  is exposed is bright, the mobile phone  1  turns off the input section display device  34 . In contrast, when the environment to which the mobile phone  1  is exposed is dark, the mobile phone  1  turns on or off the input section display device  34  according to presence/absence of the operation of the mobile phone  1  by the user. When the environment to which the mobile phone  1  is exposed is bright, the user recognizes the characters or symbols assigned to the keytops  19  from the label areas  16 . When the environment to which the mobile phone  1  is exposed is dark, if the mobile phone  1  is operated, the user recognizes the characters or symbols assigned to the keytops  19  from the keytop display images. Therefore, the mobile phone  1  appropriately switches the turning-on state and the turning-off state of the input section display device  34  according to presence/absence of the user&#39;s operation, thereby suppressing power consumption. 
       FIG. 8 , sections (A) to (C) are front views showing a state where the foldable mobile phone which is an example of the mobile apparatus according to the invention is unfolded.  FIG. 8  shows examples of a display state of the display function-equipped operation input section. 
     In the mobile phone  1  shown in  FIG. 8 , no sufficient areas cannot be allocated for the label areas  16 , and only one character type from among the input values assigned to the keytops  19  is labeled in the label areas  16 . 
     As shown in  FIG. 8 , section (A), for example, numerals from “0” to “9”, “.”, and “.” are labeled in the label areas  16  of the mobile phone  1 . No keytop display images are displayed on the keytops  19 . 
     As shown in  FIG. 8 , section (B), for example, numerals from “0” to “9”, “.”, and “.” are labeled in the label areas  16  of the mobile phone  1 . In contrast, alphabetic characters from “a” to “z” are displayed on the keytops  19  as the keytop display images. 
     As shown in  FIG. 8 , section (C), for example, numerals from “0” to “9”, “.”, and “.” are labeled in the label areas  16  of the mobile phone  1 . In contrast, numerals from “0” to “9”, “.”, and “.” are displayed on the keytops  19  as the keytop display images. 
     With respect to the states of  FIG. 8 , sections (A) to (C), for example, the following display control is performed on the display content (or a non-display state).  FIG. 9  is a flowchart showing yet another example of display control of the display function-equipped operation input section in the foldable mobile phone which is an example of the mobile apparatus according to the invention. 
     As shown in  FIG. 9 , the mobile phone  1  turns on or off the input section display device  34  according to whether or not the character type labeled in the label areas  16  is same as the character type to be displayed by the input section display device  34 . 
     If the mobile phone  1  is supplied with power and activated, first, in Step S 21 , the display controller  43  compares the character type labeled in the label areas  16  and the character type to be displayed by the input section display device  34 . The character type labeled in the label areas  16  is recorded in the memory  44  in advance. In an early phase when the mobile phone  1  is supplied with power, the character type to be displayed by the input section display device  34  is determined as required in advance. Here, it is assumed that, for example, numerals from “0” to “9” are labeled in the label areas  16 , and indication is recorded in the memory  44 . 
     When the character type shown in the label areas  16  is different from the character type to be displayed by the input section display device  34 , the display controller  43  outputs a different character type display preparation signal, and then the process progresses to Step S 22 . Otherwise, the display controller  43  outputs a “same character type display preparation signal”, and then the process progresses to Step S 25 . 
     The fact that the character type labeled in the label areas  16  is different from the character type to be displayed by the input section display device  34 , for example, means that the character type labeled in the label areas  16  is different from the character type of the keytop display images on the keytops  19 , as shown in  FIG. 8 , section (B). Otherwise, as shown in  FIG. 8 , section (C), the character type labeled in the label area  16  is the same as the character type of the keytop display images on the keytops  19 . 
     As shown in  FIG. 2 , section (C), when the mobile phone  1  is horizontally unfolded, and the display direction of a character in each of the label areas  16  is different from the display direction of an image to be displayed by the input section display device  34 , it is considered that the character type labeled in the label areas  16  is different from the character type to be displayed by the input section display device  34 . 
     Next, in Step S 22 , the illuminance measuring section  48  compares the illuminance detected by the photosensor  29  with the threshold value. When the illuminance detected by the photosensor  29  is equal to or more than the threshold value, the illuminance measuring section  48  determines that the environment to which the mobile phone  1  is exposed is bright and outputs the display stop signal. Next, the process progresses to Step S 23 . Otherwise, the illuminance measuring section  48  determines that the environment to which the mobile phone  1  is exposed is dark and outputs the display start signal. Next, the process progresses to Step S 24 . 
     Next, in Step S 23 , the main controller  40  inputs the display stop signal output from the illuminance measuring section  48  to the display controller  43 . The display controller  43  turns off the input section display device  34  or maintains the turning-off state of the input section display device  34  based on the display stop signal, and then the process returns to Step S 1 . In this case, since the environment to which the mobile phone  1  is exposed is bright, as shown in  FIG. 8 , section (A), the user can recognize the characters or symbols assigned to the keytops  19  from display of the label areas  16 . Therefore, when the environment to which the mobile phone  1  is exposed is bright, the mobile phone  1  controls the input section display device  34  so as not to emit light, thereby suppressing the amount of power consumption of the battery pack. 
     Next, in Step S 24 , the main controller  40  inputs the display start signal output from the illuminance measuring section  48  to the display controller  43 . The display controller  43  turns on the input section display device  34  or maintains the turning-on state of the light section display device  34 , and then the process returns to Step S 22 . In this case, since the environment to which the mobile phone  1  is exposed is dark, as shown in  FIG. 8 , section (C), the user can recognize the characters or symbols assigned to the keytops  19  from the keytop display images. 
     Next, in Step S 25 , the main controller  40  inputs the display start signal to the display controller  43  based on the different character type display preparation signal output from the display controller  43 . The display controller  43  turns on the input section display device  34  based on the display start signal. In this case, even if the environment to which the mobile phone  1  is exposed is bright or dark, the user can recognize the characters or symbols assigned to the keytops  19  from display of the label areas  16 , and as shown in  FIG. 8 , section (B), can recognize the characters or symbols assigned to the keytops  19  from the keytop display images. 
     That is, when the character type labeled in the label areas  16  is the same as the character type of the keytop display images, the mobile phone  1  appropriately switches the turning-on state and the turning-off state of the input section display device  34  according to the use environment thereof, thereby suppressing power consumption. In addition, when the character type labeled in the label areas  16  is different from the character type of the keytop display images, the mobile phone  1  turns on the input section display device  34 , regardless of the use environment thereof. Therefore, the mobile phone  1  appropriately switches the turning-on state and the turning-off state of the input section display device  34  according to the use environment thereof and the character type labeled in the label areas  16 , thereby suppressing power consumption. 
     When the display direction of a character displayed in each of the label areas  16  is different from the display direction of a character to be displayed by the input section display device  34 , the mobile phone  1  turns on the input section display device  34 , regardless of the use environment thereof. 
       FIG. 10  is a flowchart showing yet another example of display control of the display function-equipped operation input section in the foldable mobile phone which is an example of the mobile apparatus according to the invention. 
     As shown in  FIG. 10 , the mobile phone  1  controls turning-on or turning-off of the input section display device  34  according to whether the character type labeled in the label areas  16  is the same as the character type to be displayed by the input section display device  34 . When the character type labeled in the label areas  16  is the same as the character type to be displayed by the input section display device  34 , the mobile phone  1  does not immediately switch the turning-on state and the turning-off state of the input section display device  34  according to the use environment thereof, but it is not until the user starts to operate the mobile phone  1  that the mobile phone  1  turns on the input section display device  34 . In addition, if a threshold time elapses after the input section display device  34  is turned on until the user next operates the mobile phone  1 , the mobile phone  1  turns off the input section display device  34 . 
     Step S 31  of  FIG. 10  is the same as Step S 21  of  FIG. 9 , and thus a redundant description will be omitted. 
     In Step S 32 , the illuminance measuring section  48  compares the illuminance detected by the photosensor  29  with the threshold value. When the illuminance detected by the photosensor  29  is equal to or more than the threshold value, the illuminance measuring section  48  determines that the environment to which the mobile phone  1  is exposed is bright and outputs the display stop signal. Next, the process progresses to Step S 33 . Otherwise, the illuminance measuring section  48  determines that the environment to which the mobile phone  1  is exposed is dark and outputs the display start signal. Next, the process progresses to Step S 34 . 
     Next, in Step S 33 , the main controller  40  inputs the display stop signal output from the illuminance measuring section  48  to the display controller  43 . The display controller  43  turns off the input section display device  34  or maintains the turning-off state of the input section display device  34  based on the display stop signal, and then the process returns to Step S 32 . In this case, since the environment to which the mobile phone  1  is exposed is bright, as shown in  FIG. 8 , section (A), the user can recognize the characters or symbols assigned to the keytops  19  from display of the label areas  16 . Therefore, when the environment to which the mobile phone  1  is exposed is bright, the mobile phone  1  controls the input section display device  34  so as not to emit light, thereby suppressing the amount of power consumption of the battery pack. 
     Next, in Step S 34 , the main controller  40  determines whether or not an arbitrary keytop  19  of the display function-equipped operation input section  15  is operated. Specifically, if an arbitrary keytop  19  of the display function-equipped operation input section  15  is operated, the input controller  42  outputs an arbitrary operation signal. The main controller  40  monitors presence/absence of the input of the arbitrary operation signal. When an arbitrary operation signal is input, the main controller  40  determines that an arbitrary keytop  19  of the display function-equipped operation input section  15  is operated, and then the process progresses to Step S 35 . Otherwise, the main controller  40  determines that an arbitrary keytop  19  of the display function-equipped operation input section  15  is not operated, and then the process returns to Step S 32 . 
     Next, in Step S 35 , the main controller  40  inputs the display start signal output from the illuminance measuring section  48  to the display controller  43 . The display controller  43  turns on the input section display device  34  or maintains the turning-on state of the light section display device  34  based on the display start signal. In this case, since the environment to which the mobile phone  1  is exposed is dark, as shown in  FIG. 8 , section (C), the user can recognize the characters or symbols assigned to the keytops  19  from the keytop display images. 
     Next, in Step S 36 , the input controller  42  compares a threshold time with a time elapsed after an arbitrary keytop  19  of the display function-equipped operation input section  15 is operated. Specifically, the input controller  42  compares a threshold time with a time elapsed after an arbitrary operation signal is output. When the time elapsed after the arbitrary operation signal is output is equal to or more than the threshold time, the input controller  42  determines that no operation of the mobile phone  1  by the user is performed within the threshold time and outputs the operation stop signal. Next, the process progresses to Step S 38 . Otherwise, the input controller  42  determines that an operation of the mobile phone  1  by the user is performed within the threshold time and outputs an operation continuation signal. Next, the process progresses to Step S 37 . 
     Next, in Step S 37 , the illuminance measuring section  48  compares the illuminance detected by the photosensor  29  with the threshold value. When the illuminance detected by the photosensor  29  is equal to or more than the threshold value, the illuminance measuring section  48  determines that the environment to which the mobile phone  1  is exposed is bright and outputs the display stop signal. Next, the process progresses to Step S 38 . Otherwise, the illuminance measuring section  48  determines that the environment to which the mobile phone  1  is exposed is dark and outputs the display start signal. Next, the process returns to Step S 36 . 
     Next, in Step S 38 , the main controller  40  inputs the display stop signal output from the illuminance measuring section  48  to the display controller  43 . The display controller  43  turns off the input section display device  34  based on the display stop signal, and then the process returns to Step S 32 . In this case, even if the environment to which the mobile phone  1  is exposed is dark, no operation of the mobile phone  1  by the user is performed within the threshold time. For this reason, it is determined that the need for perceiving the characters or symbols assigned to the keytops  19  is reduced. Therefore, even if the environment to which the mobile phone  1  is exposed is dark, the mobile phone  1  controls the input section display device  34  so as not to emit light, thereby suppressing the amount of power consumption of the battery pack. 
     Next, in Step S 39 , the main controller  40  inputs the display start signal to the display controller  43  based on the different character type display preparation signal output from the display controller  43 . The display controller  43  turns on the input section display device  34  based on the display start signal. In this case, even if the environment to which the mobile phone  1  is exposed is bright or dark, the user can recognize the characters or symbols assigned to the keytops  19  from display of the label areas  16 , as shown in  FIG. 8 , section (B), can recognize the characters or symbols assigned to the keytops  19  from the keytop display images. 
     Next, in Step S 40 , the input controller  42  compares a threshold time with a time elapsed after an arbitrary keytop  19  of the display function-equipped operation input section  15  is operated. Specifically, the input controller  42  compares a threshold time with a time elapsed after an arbitrary operation signal is output. When the time elapsed after the arbitrary operation signal is output is equal to or more than the threshold time, the input controller  42  determines that no operation of the mobile phone  1  by the user is performed within the threshold time and outputs the operation stop signal. Next, the process returns to Step S 41 . Otherwise, the input controller  42  determines that an operation of the mobile phone  1  by the user is performed within the threshold time and outputs the operation continuation signal. Next, the process returns to Step S 40 . 
     Next, in Step S 41 , the main controller  40  inputs the display stop signal to the display controller  43  based on the operation stop signal output from the input controller  42 . The display controller  43  turns off the input section display device  34  based on the display stop signal. In this case, even if the environment to which the mobile phone  1  is exposed is dark, no operation of the mobile phone  1  by the user is performed within the threshold time. For this reason, it is determined that the need for perceiving the characters or symbols assigned to the keytops  19  is reduced. Therefore, even if the environment to which the mobile phone  1  is exposed is dark, the mobile phone  1  controls the input section display device  34  so as not to emit light, thereby suppressing the amount of power consumption of the battery pack. 
     Next, in Step S 42 , the main controller  40  determines whether or not an arbitrary keytop  19  of the display function-equipped operation input section  15  is operated. Specifically, if an arbitrary keytop  19  of the display function-equipped operation input section  15  is operated, the input controller  42  outputs an arbitrary operation signal. The main controller  40  monitors presence/absence of the input of the arbitrary operation signal. When an arbitrary operation signal is input, the main controller  40  determines that an arbitrary keytop  19  of the display function-equipped operation input section  15  is operated, and then the process returns to Step S 39 . Otherwise, the main controller  40  determines that an arbitrary keytop  19  of the display function-equipped operation input section  15  is not operated, and then the process returns to Step S 42 . 
     That is, when the character type labeled in the label areas  16  is the same as the character type of the keytop display images, the mobile phone  1  appropriately switches the turning-on state and the turning-off state of the input section display device  34  according to the use environment thereof, thereby suppressing power consumption. In addition, when the character type labeled in the label areas  16  is different from the character type of the keytop display images, the mobile phone  1  turns on the input section display device  34 , regardless of the use environment thereof. Furthermore, the mobile phone  1  turns on or off the input section display device  34  according to presence/absence of the operation of the mobile phone  1  by the user. Therefore, the mobile phone  1  appropriately switches the turning-on state and the turning-off state of the input section display device  34  according to the use environment thereof, the character type labeled in the label areas  16 , and presence/absence of an operation by the user, thereby suppressing power consumption. 
     As shown in  FIG. 2 , section (C), when the display direction of a character displayed in each of the label areas  16  is different from the display direction of a character to be displayed by the input section display device  34 , the mobile phone  1  turns on the input section display device  34 , regardless of the use environment thereof. 
       FIG. 11  is a flowchart showing yet another example of display control of the display function-equipped operation input section in the foldable mobile phone which is an example of the mobile apparatus according to the invention. As shown in  FIG. 11 , the mobile phone  1  controls turning-on or turning-off of the input section display device  34  according to whether or not the character type labeled in the label areas  16  is the same as the character type to be displayed by the input section display device  34 . In addition, the mobile phone  1  switches the turning-on state and the turning-off state of the input section display device  34  according to the change of the character type to be input from the display function-equipped operation input section  15 . 
     Steps S 51 , S 52 , and S 56  of  FIG. 11  are the same as Steps S 21 , S 22 , and S 25  of  FIG. 9 , respectively, and thus redundant descriptions will be omitted. 
     In Step S 53 , the main controller  40  inputs the display stop signal output from the illuminance measuring section  48  to the display controller  43 . The display controller  43  turns off the input section display device  34  or maintains the turning-off state of the input section display device  34  based on the display stop signal, and then the process returns to Step S 55 . In this case, since the environment to which the mobile phone  1  is exposed is bright, as shown in  FIG. 8 , section (A), the user can recognize the characters or symbols assigned to the keytops  19  from display of the label areas  16 . Therefore, when the environment to which the mobile phone  1  is exposed is bright, the mobile phone  1  controls the input section display device  34  so as not to emit light, thereby suppressing the amount of power consumption of the battery pack. 
     Next, in Step S 54 , the main controller  40  inputs the display start signal output from the illuminance measuring section  48  to the display controller  43 . The display controller  43  turns on the input section display device  34  or maintains the turning-on state of the light section display device  34  based on the display start signal. In this case, since the environment to which the mobile phone  1  is exposed is dark, as shown in  FIG. 8 , section (C), the user can recognize the characters or symbols assigned to the keytops  19  from display of the keytop display images. 
     Next, in Step S 55 , the main controller  40  determines whether or not the character type selection key  23  of the display function-equipped operation input section  15  is operated. Specifically, if the character type selection key  23  of the display function-equipped operation input section  15  is operated, the input controller  42  outputs a character type signal indicative of a character type being selected. The main controller  40  monitors presence/absence of the input of the character type signal. When the character type signal is input, the main controller  40  determines that the character type selection key  23  of the display function-equipped operation input section  15  is operated, and then the process returns to Step S 51 . Otherwise, the main controller  40  determines that the character type selection key  23  of the display function-equipped operation input section  15  is not operated, and then the process returns to Step S 52 . 
     Next, in Step S 57 , the main controller  40  determines whether or not the character type selection key  23  of the display function-equipped operation input section  15  is operated. Specifically, if the character type selection key  23  of the display function-equipped operation input section  15  is operated, the input controller  42  outputs a character type signal indicative of a character type being selected. The main controller  40  monitors presence/absence of the input of the character type signal. When the character type signal is input, the main controller  40  determines that the character type selection key  23  of the display function-equipped operation input section  15  is operated, and then the process returns to Step S 51 . Otherwise, the main controller  40  determines the character type selection key  23  of the display function-equipped operation input section  15 is not operated, and then the process returns to Step S 57 . 
     That is, when the character type labeled in the label areas  16  is the same as the character type of the keytop display images, the mobile phone  1  appropriately switches the turning-on state and the turning-off state of the input section display device  34  according to the use environment thereof, thereby suppressing power consumption. In addition, when the character type labeled in the label areas  16  is different from the character type of the keytop display images, the mobile phone  1  turns on the input section display device  34 , regardless of the user environment thereof. Furthermore, if a character type that can be input from the display function-equipped operation input section  15  is changed, the character type to be displayed by the input section display device  34  is also appropriately changed. Therefore, the mobile phone  1  appropriately switches the turning-on state and the turning-off state of the input section display device  34  according to the use environment thereof, the character type labeled in the label areas  16 , and the change of the character type to be input from the display function-equipped operation input section  15 , thereby suppressing power consumption. 
     When the display direction of a character displayed in each of the label areas  16  is different from the display direction of a character to be displayed by the input section display device  34 , the mobile phone  1  turns on the input section display device  34 , regardless of the use environment thereof. 
       FIG. 12  is a flowchart showing another example of display control of the display function-equipped operation input section in the foldable mobile phone which is an example of the mobile apparatus according to the invention. 
     As shown in  FIG. 12 , the mobile phone  1  turns on or off the input section display device  34  according to whether or not the character type labeled in the label areas  16  is the same as the character type to be displayed by the input section display device  34 . When the character type labeled in the label areas  16  is the same as the character type to be displayed by the input section display device  34 , the mobile phone  1  does not immediately switch the turning-on state and the turning-off state of the input section display device  34  according to the use environment thereof, but stands by turning-on of the input section display device  34  until the user starts to operate the mobile phone  1 . In addition, the mobile phone  1  switches the turning-on state and the turning-off state of the input section display device  34  according to the change of the character type to be input from the display function-equipped operation input section  15 . Furthermore, if a threshold time elapses after the input section display device  34  is turned on until the user next operates the mobile phone  1 , the mobile phone  1  turns off the input section display device  34 . 
     Step S 61  of  FIG. 12  is the same as Step S 21  of  FIG. 9 , and Steps S 62 , S 65  to S 67 , S 70 , S 71 , S 74 , and S 75  of  FIG. 12  are the same as Steps S 32 , S 34  to S 36 , S 38 , S 39 , S 41 , and S 42  of  FIG. 10 , respectively. Thus, redundant descriptions will be omitted. 
     Next, in Step S 63 , the main controller  40  inputs the display stop signal output from the illuminance measuring section  48  to the display controller  43 . The display controller  43  turns off the input section display device  34  or maintains the turning-off state of the input section display device  34  based on the display stop signal. In this case, since the environment to which the mobile phone  1  is exposed is bright, as shown in  FIG. 8 , section (A), the user can recognize the characters or symbols assigned to the keytops  19  from display of the label areas  16 . Therefore, when the environment to which the mobile phone  1  is exposed is bright, the mobile phone  1  controls the input section display device  34  so as not to emit light, thereby suppressing the amount of power consumption of the battery pack. 
     Next, in Step S 64 , the main controller  40  determines whether or not the character type selection key  23  of the display function-equipped operation input section  15  is operated. Specifically, if the character type selection key  23  of the display function-equipped operation input section  15  is operated, the input controller  42  outputs a character type signal indicative of a character type being selected. The main controller  40  monitors presence/absence of the input of the character type. When the character type signal is input, the main controller  40  determines that the character type selection key  23  of the display function-equipped operation input section  15  is operated, and then the process returns to Step S 61 . Otherwise, the main controller  40  determines that the character type selection key  23  of the display function-equipped operation input section  15  is not operated, and then the process returns to Step S 62 . 
     Next, in Step S 68 , the illuminance measuring section  48  compares the illuminance detected by the photosensor  29  with the threshold value. When the illuminance detected by the photosensor  29  is equal to or more than the threshold value, the illuminance measuring section  48  determines that the environment to which the mobile phone  1  is exposed is bright and outputs the display stop signal. Next, the process returns to Step S 70 . Otherwise, the illuminance measuring section  48  determines that the environment to which the mobile phone  1  is exposed is dark and outputs the display start signal. Next, the process returns to Step S 69 . 
     Next, in Step S 69 , the main controller  40  determines whether or not the character type selection key  23  of the display function-equipped operation input section  15  is operated. Specifically, if the character type selection key  23  of the display function-equipped operation input section  15  is operated, the input controller  42  outputs a character type signal indicative of a character type being selected. The main controller  40  monitors presence/absence of the input of the character type signal. When the character type signal is input, the main controller  40  determines that the character type selection key  23  of the display function-equipped operation input section  15  is operated, and then the process returns to Step S 61 . Otherwise, the main controller  40  determines that the character type selection key  23  of the display function-equipped operation input section  15  is not operated, and then the process returns to Step S 67 . 
     Next, in Step S 72 , the input controller  42  compares a threshold time with a time elapsed after an arbitrary keytop  19  of the display function-equipped operation input section  15 is operated. Specifically, the input controller  42  compares a threshold time with a time elapsed after an arbitrary operation signal is output. When the time elapsed after the arbitrary operation signal is output is equal to or more than the threshold time, the input controller  42  determines that no operation of the mobile phone  1  by the user is performed within the threshold time and outputs the operation stop signal. Next, the process returns to Step S 74 . Otherwise, the input controller  42  determines that an operation of the mobile phone  1  by the user is performed and outputs the operation continuation signal. Next, the process returns to Step S 73 . 
     Next, in Step S 73 , the main controller  40  determines whether or not the character type selection key  23  of the display function-equipped operation input section  15  is operated. Specifically, if the character type selection key  23  of the display function-equipped operation input section  15  is operated, the input controller  42  outputs a character type signal indicative of a character type being selected. The main controller  40  monitors presence/absence of the input of the character type signal. When the character type signal is input, the main controller  40  determines that the character type selection key  23  of the display function-equipped operation input section  15  is operated, and then the process returns to Step S 61 . Otherwise, the main controller  40  determines that the character type selection key  23  of the display function-equipped operation input section  15  is not operated, and then the process returns to Step S 72 . 
     That is, when the environment to which the mobile phone  1  is exposed is bright, the mobile phone  1  turns off the input section display device  34 . In contrast, when the environment to which the mobile phone  1  is exposed is dark, the mobile phone  1  turns on or off the input section display device  34  according to presence/absence of the operation of the mobile phone  1  by the user. When the environment to which the mobile phone  1  is exposed is bright, the user recognizes the characters or symbols assigned to the keytops  19  from display of the label areas  16 . When the environment to which the mobile phone  1  is exposed is dark, if the mobile phone  1  is operated, the user recognizes the characters or symbols assigned to the keytops  19  from display of the keytop display images. In addition, when the character type labeled in the label areas  16  is the same as the character type of the keytop display images, the mobile phone  1  appropriately switches the turning-on state and the turning-off state of the input section display device  34  according to the use environment thereof, thereby suppressing power consumption. Furthermore, when the character type labeled in the label areas  16  is different from the character type of the keytop display images, the mobile phone  1  turns on the input section display device  34 , regardless of the use environment thereof. Furthermore, if a character type that can be input from the display function-equipped operation input section  15  is changed, the character type to be displayed by the input section display device  34  is also appropriately changed. Therefore, the mobile phone  1  appropriately switches the turning-on state and the turning-off state of the input section display device  34  according to the use environment thereof, the character type labeled in the label areas  16 , presence/absence of the user&#39;s operation, and the change of the character type to be input from the display function-equipped operation input section  15 , thereby suppressing power consumption. 
     When the display direction of a character displayed in each of the label areas  16  is different from the display direction of a character to be displayed by the input section display device  34 , the mobile phone  1  turns on the input section display device  34 , regardless of the use environment thereof. 
     As a result, the mobile apparatus according to this embodiment includes the keytops  19  on which arbitrary images can be displayed, can realize very low power consumption, and can be used over a long time. 
     The invention may be applied to, in addition to the mobile phone  1 , a Personal Digital Assistant (PDA), a personal computer, a portable game machine, a portable music player, a portable motion picture player, and other mobile apparatuses. 
     A series of processing described in the embodiment of the invention may be performed by software or may be performed by hardware. 
     Although in the embodiment of the invention, an example where the steps in the flowchart are performed in time series according to the described sequence has been described, the steps may be not necessarily performed in time series. For example, the steps maybe performed in parallel or individually.