Patent Publication Number: US-2007103434-A1

Title: Portable communication device and power saving method used therein

Description:
TECHNICAL FIELD  
      The present invention relates to portable communication devices and power saving methods thereof, and particularly to a portable communication device having two displays and power saving method used therein.  
     GENERAL BACKGROUND  
      With the fast development in electronic technologies, many different models of portable communication devices have been introduced in the electronics consumer market, products such as cell phones, personal digital assistants (PDA), etc., readily satisfying a business requirement or a personal convenience requirement. Particularly, cell phones have become ubiquitous in modern society. Cell phones enable individuals to be easily contacted when they are out shopping, commuting, or at any other locations where land line communications are not possible.  
      One of the greatest limitations regarding the cell phones is their inability to remain powered for extended periods of time. Since cell phones receive power from built-in batteries, power conservation is important for cell phones. The less power the cell phones consume, the longer the cell phone is operable without interruptions.  
      With respect to the cell phone, display(s) is a relatively larger component thereof. Accordingly, the display of a cell phone consumes relatively more power than other components of the cell phone. Furthermore, the display is required to be kept in a power on state to display real-time information such as time, battery energy level, incoming calls information, etc. As a result, more power consumption is consumed by the display. Therefore, in order to reduce power consumption by the cell phone as a whole, limiting power consumption of the display of a cell phone may be an effective method.  
      Accordingly, cell phones with two displays are introduced. These cell phones display real-time information on a small display instead of a large display, resulting in less power consumption since the small display needs less power than the large display. However, regarding these cell phones, the large display thereof is also powered on during a communication call, nevertheless, the large display may not be in use by users since the users often do not view the displays during the communication calls. In other words, these cell phones are still not capable of effectively limiting power consumption of the displays thereof.  
      What is needed, therefore, is a portable communication device with two displays and power saving method used therein, which can relatively effectively manage power consumption of the displays, thereby saving power consumption on the battery of the portable communication device, and thus to extending an operation time of the portable communication device.  
     SUMMARY  
      A portable communication device is provided. The device has a primary display, a secondary display, and a processing unit. The processing unit is programmed for controlling the primary display and the secondary display according to a current state of the device. The processing unit has the primary display in a power off state if the current state is selected from the group of consisting of a standby state, an incoming call state, a dialing state, and a communication call state.  
      A power saving method used in a portable communication device is also provided, wherein the portable communication device has a primary display and a secondary display. The method includes the steps of: (a) detecting a current state of the portable communication device; and (b) controlling the primary display to be in a power off state, if the current state is selected from the group consisting of a standby state, an incoming call sate, a dialing state, and a communication call state.  
      Other advantages and novel features will be drawn from the following detailed description with reference to the attached drawing, in which: 
    
    
     BRIEF DESCRIPTION OF DRAWINGS  
       FIG. 1  is a schematic diagram of a hardware infrastructure of a portable communication device in accordance with a preferred embodiment of the present invention;  
       FIG. 2  is a flowchart of a preferred display method used in the portable communication device of  FIG. 1 ; and  
       FIG. 3  is a flowchart of a preferred method of implementing one step of  FIG. 2 , namely controlling a primary display and a secondary display of the portable communication device. 
    
    
     DETAILED DESCRIPTION  
       FIG. 1  is a schematic diagram of a hardware infrastructure of a portable communication device in accordance with a preferred embodiment of the present invention. The portable communication device enables users to be contactable while on the move. The portable communication device can be, without limitation, cell phones, personal digital assistants, and/or pagers. While the following discussion is couched in terms of a cell phone, it is equally applicable to other portable communication devices.  
      The portable communication device, i.e., the cell phone, has a primary display  10 , a secondary display  11 , a processing unit  12 , and a plurality of input devices  13  such as input keys.  
      The primary display  10  is relatively larger than the secondary display thereby able to display more information. Nevertheless, the primary display  10  consumes more power than the secondary display  11 . In other words, the cell phone consumes more power to display information on the primary display  10  than to display information on the secondary display  11 .  
      The input devices  13  are for operational inputs such as, for example answering an incoming call, dialing an outgoing call, editing text messages, viewing text messages, etc.  
      The cell phone further includes a memory, a transmitter/receiver (transceiver) assembly, an antenna, a data card reader for receiving a data card (e.g., a subscriber identification module (SIM) card, a user identification module (UIM) card), and the like. Since these components are not prime components that consume a significantly large amount of power on a battery of the cell phone, detailed explanations of these components will be omitted.  
      The processing unit  12  is programmed for controlling the components of the cell phone such as, for example, the primary display  10 , the secondary display  11 , and the input devices.  
      The processing unit  12  is capable of controlling the primary display  10  and the secondary display  11  according to a current state of the cell phone. Typically, if there is an incoming call to the cell phone, namely the current state of the cell phone is in an incoming call state, the processing unit  12  displays information of the incoming call on the secondary display  11  and leaves the primary display  10  in a power off state; if the cell phone is communicating with other cell phone(s), namely the current state of the cell phone is in a communication call state, the processing unit  12  still leaves the primary display  10  in the power off state; if there is a dialing operation (including a new dialing operation and a redialing operation) on the cell phone, namely the current state of the cell phone is in a dialing state, the processing unit  12  displays information of an outgoing call on the secondary display  11  and also leaves the primary display  10  in the power off state.  
      The states described above (i.e., incoming call state, communication call state, and dialing state) constitutes a procedure of call processing. Since a major function of the cell phone revolves around the procedure of call processing, limiting power consumption is most effective by retaining the primary display  10  to be in the power off state during those states.  
      Additionally, during the procedure of call processing, the processing unit  10  identifies each state based on inputs received by the processing unit  10 . For example, if the transmitter/receiver is receiving an incoming call to the cell phone, the processing unit  12  regards the current state of the cell phone as in the incoming call state; if receiving an operational input of answering the incoming call, the processing unit  12  regards the current state of the cell phone as in the communication call state; if receiving operational inputs of dialing an outgoing call, the processing unit  12  regards the current state of the cell phone as in the dialing state.  
      Furthermore, if receiving operational inputs for information operations such as, for example, editing text messages, viewing text messages, etc., the processing unit  12  regards the current state of the cell phone as in an information processing state. Consequently, an information display operation is required on the primary display  10 , that is, the processing unit  12  controls the primary display  10  to be in a power on state to display information in response to the operational inputs for information operations.  
      In addition, in each state, the processing unit  12  further displays system information (e.g., time, battery energy level, etc.,) on the secondary display  11 .  
       FIG. 2  is a flowchart of a preferred display method used in the portable communication device of  FIG. 1 . In step S 20 , namely the cell phone in a standby state, the processing unit  12  controls the primary display  10  to be in the power off state and displays system information, namely real-time information, on the secondary display  11 . In step S 21 , the processing unit  12  detects the current state of the cell phone in real-time. In step S 22 , the processing unit  12  controls the primary display  10  and the secondary display  11  according to the current state of the cell phone detected. That is, the processing unit  12  retains the primary display  10  in the power off state if the current state of the cell phone is in the procedure of call processing or the standby state, otherwise, the processing unit  12  controls the primary display  10  to be in the power on state for displaying information. Simultaneously, the processing unit  12  displays corresponding real-time information on the secondary display  11  according to the current state of the cell phone detected. For example, in the incoming call state or the dialing call state of the cell phone, the processing unit  12  displays information of the incoming call or the outgoing call on the secondary display  11 , otherwise, the processing unit  12  displays the system information on the secondary display  11 .  
       FIG. 3  is a flowchart of a preferred method of implementing step S 22  of  FIG. 2 . In step S 30 , the processing unit  12  detects whether the current state of the cell phone is in the incoming call state, that is, the processing unit  12  detects whether the cell phone receives the incoming call.  
      If the current state of the cell phone is in the incoming call state, in step S 31 , the processing unit  12  retains the primary display  10  to be in the power off state and displays the information of the incoming call on the secondary display  11 , and the procedure returns to step S 21 .  
      If the current state of the cell phone is not in the incoming call state, in step S 32 , the processing unit  12  detects whether the current state of the cell phone is in the communication call state, that is, the processing unit  12  detects whether the cell phone receives the operational input of answering the incoming call.  
      If the current state of the cell phone is the communication call state, in step S 33 , the processing unit  12  retains the primary display  10  to be in the power off state and continues to display the system information on the secondary display  11 , and the procedure returns to step S 21 .  
      If the current state of the cell phone is not in the communication call state, in step S 34 , the processing unit  12  detects whether the current state of the cell phone is in the dialing state, that is, the processing unit  12  detects whether the cell phone receives operational inputs of dialing an outgoing call.  
      If the current state of the cell phone is in the dialing state, in step S 35 , the processing unit  12  retains the primary display  10  to be in the power off state and displays the information of the outgoing call on the secondary display  11 , and the procedure returns to step S 21 .  
      If the current state of the cell phone is not in the dialing state, in step S 36 , the processing unit  12  detects whether the current state of the cell phone is in the information processing state, that is, the processing unit  12  detects whether the cell phone receives operational inputs for information operations.  
      If the current state of the cell phone is in the information processing state, in step S 37 , the processing unit  12  controls the primary display  10  to be in the power on state to display information in response to the operational inputs for information operations and continues to display the system information on the secondary display  11 , and the procedure returns to step S 21 .  
      If the current state of the cell phone is not in the information processing state, that is, the processing unit  12  does not receive any inputs, and the cell phone is in the standby state, thereupon the procedure returns to step S 20 .  
      Accordingly, in one aspect, the present invention relates to software stored on a computer readable medium for saving power of a portable communication device, wherein the portable communication device has a primary display and a secondary display, to perform functions including: (a) detecting a current state of the portable communication device; (b) retaining the primary display in a power off state, if the current state of a portable communication device is either in a standby state, an incoming call state, a dialing state, and a communication call state, otherwise, powering on the primary display to display information; (c) displaying information of an incoming call on the secondary display if the current state of a portable communication device is in the incoming call state; and (d) displaying information of an outgoing call on the secondary display if the current state of a portable communication device is in the dialing state. The software can be stored on a computer readable medium and read by a controller or processing unit  12  to perform corresponding functions.  
      Although the present invention has been specifically described on the basis of a preferred embodiment and preferred method thereof, the invention is not to be construed as being limited thereto. Various changes or modifications may be made to the embodiment and method without departing from the scope and spirit of the invention.