Abstract:
There is provided a control method for driving backlight parts to provide backlight to a display and a keypad in a mobile terminal. The display backlight part and the keypad backlight part are controlled to be selectively driven, according to the state of the cover and the presence or absence of key input data. Therefore, power dissipation caused by unnecessary operation of the backlights can be prevented.

Description:
PRIORITY 
     This application claims priority to an application entitled “Control Method for Driving Backlight Parts in Mobile Phone” filed in the Korean Industrial Property Office on Aug. 19, 2000 and assigned Serial No. 2000-48159, the contents of which are hereby incorporated by reference. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to a mobile phone, and in particular, to a control method for driving backlight parts to provide a backlight to a display and a keypad. 
     2. Description of the Related Art 
     In general, a mobile phone has a backlight function that allows a user to identify information on a display and keys on a keypad. Thus, the mobile phone includes a display backlight part for providing backlight to a display, such as an LCD (Liquid Crystal Display), and a keypad backlight part for providing backlight to the keypad. Typically, an EL (Electroluminescence Element) is used to display the backlight part and an LED (Light Emitting Diode) is used to display the keypad backlight part. The display backlight part and the keypad backlight part are driven, according to the state of the mobile phone. 
     FIG. 1 is a block diagram of a mobile phone, mainly illustrating parts related with driving backlight parts. Referring to FIG. 1, an RF (Radio Frequency) module  100  processes an RF signal and transmits/receives the RF signal under the control of a controller  106 . A keypad  102  is provided with a plurality of digit keys and function keys and transmits data corresponding to key input to the controller  106 . A cover monitor  104  senses the closing and opening of a flip cover or a folder cover and notifies the controller  106  of the cover state. The controller  106  turns ON or turns OFF a display backlight part  108  and a keypad backlight part  110 , according to the key data received from the keypad  102 , depending on the cover state data received from the cover monitor  104 . 
     The method for driving the display backlight part  108  and the keypad backlight part  110  will be described in FIG.  2 . 
     In step  200 , the controller  106  determines whether key input data has been received or, if the cover is opened. Upon receipt of the key input data from the keypad  102 , or upon receipt of information indicating that the cover has been opened from the cover monitor  104 , the controller  106  turns ON both the display backlight part  108  and the keypad backlight part  110  in step  202 . Hence, backlight is provided to a display (not shown) and the keypad  102 . In this state, the controller  106  checks whether a predetermined time has elapsed in step  204 . When the predetermined time has elapsed, the controller  106  turns OFF both the display backlight part  108  and the keypad backlight part  110  in step  206 , thereby preventing power dissipation caused by the long ON-state of the display backlight part  108  and the keypad backlight part  110 . 
     In the conventional control method, as described above, the display backlight part and the keypad backlight part are turned ON at the same time when a user presses a key or opens a flip or folder cover. However, in the case that the user intends to view an RSSI (Received Signal Strength Indicator) or time on the display, he often turns ON the display backlight part just by manipulating an external key like a volume key without opening the cover. In this case, due to the mechanism of simultaneously turning ON/OFF the display backlight part and the keypad backlight part, a backlight is unnecessarily provided to the keypad when the cover is closed. 
     In the case of a so-called dual folder-type mobile phone having two displays, one of them is disposed on the outer surface of its folder cover to allow a user to view the display, even if the folder cover is closed, and the other display is disposed in such a way that it can be seen only when the folder cover is opened. An RSSI or time is displayed on the outer display. However, a user sometimes manipulates an external key when he wants to view the RSSI or time without opening the folder cover in the dual folder-type mobile phone, as in a flip-type mobile phone and a folder-type mobile phone, having a single display. According to the above conventional method, both backlight parts for the outer display and the inner display are turned ON even though it is not necessary to turn ON the backlight part for the inner display. 
     Therefore, a backlight part that is unnecessarily turned ON increases power dissipation, and as a result the life of a battery decreases. 
     A need exists for a method and an apparatus that enables a folder or flip-type mobile communication terminal to decide if a backlight part or a keypad backlight part should be turned ON, so the power, of the mobile communication terminal, will not be dissipated. 
     SUMMARY OF THE INVENTION 
     It is, therefore, an object of the present invention to provide a method for driving backlight parts to prevent power dissipation caused by unnecessary operation of a display backlight part and a keypad backlight part in a mobile phone. 
     To achieve the above object, there is provided a method for driving backlight parts to provide a backlight to a display and a keypad in a mobile terminal. The display backlight part and the keypad backlight part are controlled to be selectively driven, according to the state of the cover and the presence or absence of key input data. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The above and other objects, features and advantages of the present invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings in which: 
     FIG. 1 is a block diagram of a conventional mobile phone, mainly illustrating components related to driving backlight parts; 
     FIG. 2 is a flowchart illustrating a control operation for driving the backlight parts in the conventional mobile phone; 
     FIG. 3 is a block diagram of a mobile phone, mainly illustrating components related with control of driving backlight parts, according to an embodiment of the present invention; 
     FIG. 4 is a flowchart illustrating a control operation for driving the backlight parts in the mobile phone, according to the embodiment of the present invention; 
     FIG. 5 is a block diagram of a mobile phone, mainly illustrating components related with control of driving backlight parts, according to another embodiment of the present invention; and 
     FIG. 6 is a flowchart illustrating a control operation for driving the backlight parts in the mobile phone, according to the second embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     A preferred embodiment of the present invention will be described hereinbelow with reference to the accompanying drawings. In the following description, well-known functions or constructions are not described in detail since they would obscure the invention in unnecessary detail. 
     FIG. 3 is a block diagram of a mobile phone that utilizes a method to control driving backlight parts according to an embodiment of the present invention. For a folder or flip-type mobile phone having a single display, a controller  306  selectively drives a display backlight part  308  and a keypad backlight part  310 , as compared to the conventional mobile phone, shown in FIG.  1 . An RF module  300 , a keypad  302 , and a cover monitor  304  are the same as their counterparts in FIG.  1 . 
     A control operation of driving the display backlight part  308  and the keypad backlight part  310  in the controller  306  will be described with reference to FIG.  4 . 
     In step  400 , the controller  306  checks whether a cover is open. If the controller  306  senses that the cover is open, through the cover monitor  304 , it turns ON both the display backlight part  308  and the keypad backlight part  310  in step  404 . Thus, a backlight is provided to a display (not shown) and the keypad  302  so that when the user opens the cover he can view the display or manipulate the keypad  302 , conveniently, similarly to the conventional method. The controller  306  checks whether a predetermined time has elapsed in step  406 . If the predetermined time has elapsed, the controller  306  turns OFF both the display backlight part  308  and the keypad backlight part  310  in step  408 . 
     When the cover is not opened in step  400 , the controller  306  checks whether key input data has been received from the keypad  302  in step  402 . Upon receipt of the key input data, the controller  306  turns ON only the display backlight part  308  in step  410 . Therefore, when the user presses an external key without opening the cover to see an RSSI or time on the display, that is, when there is key input with the cover closed, a backlight is provide only to the display backlight part  308 , thereby saving power that is otherwise dissipated due to unnecessarily turning ON the keypad backlight part  310 , as compared to the conventional method. In step  412 , the controller  306  checks whether the predetermined time has elapsed. If the predetermined time has elapsed, the controller  306  turns OFF the display backlight part  308  in step  414 . 
     FIG. 5 is a block diagram of a mobile phone that is utilized to control driving backlight parts, according to another embodiment of the present invention. For a dual folder-type mobile phone having two displays, a controller  506  selectively drives a first display backlight part  508 , a second display backlight part  510 , and a keypad backlight part  512 . An outer display (not shown) installed on a folder cover is called “a first display” and an inner display (not shown) installed to be covered by the folder cover when the folder cover is closed is called “a second display.” The first display backlight part  508  provides backlight to the first display and the second display backlight part  510  provides backlight to the second display. An RF module  500 , a keypad  502 , and a cover monitor  504  are the same as their counterparts in FIG.  3 . 
     A control operation of driving the first and second display backlight parts  508  and  510  and the keypad backlight part  512  in the controller  506  will be described with reference to FIG.  6 . 
     In step  600 , the controller  506  checks whether the folder cover is open. If the controller  506  senses that the cover is open, through the cover monitor  504 , it turns on both the second display backlight part  510  and the keypad backlight part  512  in step  604 . Thus, a backlight is provided to the second display and the keypad  502  so that when the user opens the cover he can view the second display or manipulate the keypad  502 , conveniently. In this case, the first display is not turned ON unnecessarily. The controller  506  checks whether a predetermined time has elapsed in step  606 . If the predetermined time has elapsed, the controller  506  turns OFF both the second display backlight part  510  and the keypad backlight part  512  in step  608 . As an alternative embodiment, the controller controls all three separate backlight parts. Controller  506  can utilize a single control line to control first display backlight part  508 , and utilize separate control lines to control second display backlight part  510  and keypad backlight part  512 . For example, if first display backlight part  508  is turned ON, by controller  506 , then second display backlight part  510  or keypad backlight part  512  can be turned ON or OFF, depending on controller  506 . 
     When the cover is not opened in step  600 , the controller  506  checks whether key input data has been received from the keypad  502  in step  602 . Upon receipt of the key input data, the controller  506  turns ON only the first display backlight part  508  in step  610 . Therefore, when the user presses an external key without opening the cover to see an RSSI or time on the first display, the backlight is provided only to the first display, thereby saving power that is otherwise dissipated due to unnecessarily turning ON the second display and the keypad backlight part  512 . In step  612 , the controller  506  checks whether the predetermined time has elapsed. If the predetermined time has elapsed, the controller  506  turns OFF the first display backlight part  508  in step  614 . 
     In accordance with the embodiments of the present invention as described above, the display backlight parts and the keypad backlight part are selectively turned ON according to whether a cover is opened or closed and whether key input data has been received. Therefore, unnecessary power dissipation is prevented and the life of a battery can be increased. 
     While the invention has been shown and described with reference to certain preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.