Patent Publication Number: US-2006020887-A1

Title: Portable radio terminal

Description:
BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      The present invention relates to a portable radio terminal having a display section, such as a portable telephone, and more particularly to a technique of controlling lightness of a display screen of the display section.  
      2. Description of the Related Art  
      Generally, a portable radio terminal such as a portable telephone has a liquid crystal display. The liquid crystal display includes a display screen and a backlight for illuminating the display screen. When the portable radio terminal is used, the backlight automatically lights up to clearly display characters and images on the display screen. A battery (secondary battery) built into the portable radio terminal supplies power to the backlight. Thus, lighting of the backlight shortens the usable period of the portable radio terminal.  
      In order to solve this problem, JP 2002-94656 A discloses a technique in which illuminating a display screen is suspended during voice communication to reduce the power consumption of the wireless communication terminal. In addition, JP 2002-123231 A discloses a technique in which, in a portable telephone, lighting time of a backlight is determined according to the number of characters contained in an e-mail to be displayed or a scroll operation.  
      The display screens of recent portable telephones display various images, such as still images of photographs or the like, moving images, and game images, in addition to characters. The display screens need to have a certain brightness level or more to clearly display those color images. However, high brightness of the display screen consumes large electric power.  
     SUMMARY OF THE INVENTION  
      A portable radio terminal according to an aspect of the present invention includes a display section, a determination section, and a control section. The display section includes a display screen. The determination section determines whether data to be displayed on the display screen is text data or not. The control section sets lightness of the display screen according to each of text data and data other than the text data, to be displayed on the display screen.  
      A portable radio terminal according to another aspect of the present invention includes a display section that has a display screen, and a control section that sets the lightness of the display screen according to each function of the portable radio terminal.  
      In the portable radio terminal, the control section can include a key input section from which the lightness of the display screen is set according to an input. The portable radio terminal can include a storage section that stores the set lightness.  
      With a portable radio terminal according to the present invention, a user can determine the lightness of the display screen according to the type of data to be displayed on the display screen or a function of the portable radio terminal to reduce the power consumption of the display section. 
    
    
     BRIEF DESCRIPTION OF THE DRAWING  
      The above and other objects, features and advantages of the present invention will become apparent form the following detailed description when taken with the accompanying drawings in which:  
       FIG. 1  is a block diagram of a portable radio terminal according to an embodiment of the present invention;  
       FIG. 2  is a flow chart of an operation example of the portable radio terminal according to the embodiment of the present invention;  
       FIG. 3  shows examples of a display screen for setting lightness, of the portable radio terminal according to the embodiment of the present invention;  
       FIG. 4  is a flowchart of an operation example of a portable radio terminal according to another embodiment of the present invention;  
       FIG. 5  shows examples of a display screen for setting lightness, of the portable radio terminal according to the another embodiment of the present invention; and  
       FIG. 6  shows examples of a display screen for setting lightness, of a portable radio terminal according to still another embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
      Preferred embodiments of the present invention will be described below.  FIG. 1  shows a configuration example of a portable telephone as an example of a portable radio terminal of the present invention. The portable telephone includes an antenna  1 , a radio section  2 , a display section  3 , a lighting section  4 , a storage section  5 , a control section  7 , a speaker  8 , a microphone  9 , and a key input section  10 . The display section  3  includes a liquid crystal display, for example, and has a display screen. The display screen can display telephone numbers, e-mails, other text data, web contents, game images, still images, and moving images. The lighting section  4  includes a backlight or the like which illuminates the display screen. The storage section  5  stores or memorizes lightness set according to the type of data to be displayed and lightness set according to a function of the portable telephone. The storage section  5  includes a function table  6  of the portable telephone. The control section  7  controls the whole portable telephone. The control section  7  can identify a selected function of the portable telephone and the type of data to be displayed on the display screen. The control section  7  controls the display section  3  and the lighting section  4  based on data concerning the lightness stored in the storage section  5 . Further, the control section  7  can control the backlight to control the lightness of the display screen when the display section  3  displays text data. When the display section  3  displays, for example, color images or game images, the control section  7  can control the brightness of the color images or the game images. The key input section  10  includes a cursor key  11  and a confirmation key  12 . The portable telephone further includes a vibrator and a battery.  
       FIG. 2  shows an example in which the display screen is controlled at two lightness levels. The lightness of the display screen (for example, the amount of current to be supplied to the lighting section  4 ) is set according to data to be displayed (S 1 ). The manufacturer of the portable telephone or the user can set the lightness. The set lightness is stored or memorized in the storage section  5  (S 2 ). At the time of starting operation of the portable telephone, the control section  7  determines the type of data displayed on the display screen (S 3 ). When text data is displayed on the display screen (S 4 ), a small amount of current is supplied to the lighting section  4  (backlight) (S 5 ) and the lighting section  4  is set to be dark (S 6 ). On the other hand, when data other than text data is displayed on the display screen (S 4 ), a larger amount of current than the above current is supplied to the lighting section  4  (backlight) (S 7 ) and the lighting section  4  is set to be bright (S 8 ).  
       FIG. 3  shows examples of the display screen for the user to control the lightness, in the control example shown in  FIG. 2 . When the user displays an initial screen for the lighting control and selects “YES” in the screen, the contents of the current setting about the lightness of the display screen are displayed. When the user selects data other than text data, a screen for setting the lightness of the display screen for displaying data other than text data appears. The screen shows that the display screen is currently set to a dark state. When the user selects a bright state, a screen showing the changed setting contents of the display screen appears. The screen shows that data other than text data is to be displayed in the bright state. As a result of the above-mentioned operation, data (such as still images, moving images, and game images) other than text data is displayed in the bright state. On the other hand, text data (such as e-mails and telephone numbers) is displayed in the dark state so that the power consumption of the battery is suppressed.  
       FIG. 4  shows an example of a basic control in which the lighting section  4  is controlled at five lightness levels. First, the user determines whether the set lightness of the display screen is maintained or changed (S 10 ). When the user operates a predetermined key, a screen for setting the lightness of the display screen appears (S 11 ). The user changes the currently-set lightness of the display screen (S 12 ). If the user satisfies the lightness of the display screen after the change, the lightness control operation ends (YES in S 13 ). If the user desires to change again the lightness of the display screen, the above operation is repeated (NO in S 13 ).  
       FIG. 5  shows examples of the display screen for the user to control the lightness, in the control example shown in  FIG. 4 . When the user displays an initial screen for the lighting control and selects “YES” in the screen, the contents of the current setting of the display screen are displayed. In the current setting, when the display screen displays text data, the lightness of the display screen has been set to a second lightness level out of the five levels, and when the display screen displays data other than text data, the lightness of the display screen has been set to a fifth lightness level (brightest level) out of the five levels. If the user selects data other than text data, a screen for setting the lightness of the display screen for displaying data other than text data appears. On the screen, the user can select a desired lightness level from among the five lightness levels. In the example, the user selects a fourth lightness level from among the five lightness levels on the screen. Then, a screen showing the changed setting contents of the display screen appears again. The user can confirm the result selected by himself/herself, on the screen.  
       FIG. 6  shows an example in which the lighting section  4  is controlled at five lightness levels according to a function of the portable telephone.  FIG. 6  specifically shows examples of the display screen which appear during the control. When the user displays an initial screen for the lighting section control and selects “YES” in the screen; the contents of the current setting of the display screen are displayed. In the screen, lightness levels which are set according to respective functions of the portable telephone are displayed. In  FIG. 6 , four functions of game, image display, e-mail display, and “others” are illustrated as functions of the portable telephone. A fourth lightness level has been assigned to the function of game, a fifth lightness level, which is the brightest level, has been assigned to the function of image display, a second lightness level has been assigned to the function of e-mail display, and a first lightness level, which is the darkest level, has been assigned to the function of “others”. To change the lightness of the image display, the user selects “image” in the screen. Then, a screen for setting the lightness of the display screen concerning the image appears. In this example, the user selects the fourth lightness level from among the lightness levels. A screen showing the changed setting contents of the display screen appears. The user can confirm the result selected by himself/herself, on the screen. The user can set the lightness of the display screen for each function of the portable telephone to reduce the power consumption of the battery.  
      The number of lightness levels of the display screen is not limited to the two levels or the five levels. The control section can set the display screen to any lightness within a range of a predetermined lightness, and store the lightness in the storage section.  
      While the present invention has been described in connection with certain preferred embodiments, it is to be understood that the subject matter encompassed by the present invention is not limited to those specific embodiments. On the contrary, it is intended to include all alternatives, modifications, and equivalents as can be included within the spirit and scope of the following claims.  
      Further, it is the inventor&#39;s intent to refrain all equivalents of the claimed invention even if the claims are amended during prosecution.