Abstract:
A screen control method and apparatus for a mobile terminal including multiple touch screens are provided. The screen control method includes displaying at least one application screen on the touch screens, detecting touch gestures made on the touch screens, identifying the detected touch gestures made on the touch screens, and changing at least one of application screens on the touch screens according to the identified touch gestures. Hence, multiple touch screens can be controlled and a display screen can be changed by simple touch gestures.

Description:
PRIORITY 
       [0001]    This application claims the benefit under 35 U.S.C. §119(a) of a Korean patent application filed on Feb. 10, 2010 in the Korean Intellectual Property Office and assigned Serial No. 10-2010-0012477, the entire disclosure of which is hereby incorporated by reference. 
       BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to a mobile terminal including multiple touch screens. More particularly, the present invention relates to a screen control method and apparatus for a mobile terminal including multiple touch screens for controlling a screen display according to touch inputs. 
         [0004]    2. Description of the Related Art 
         [0005]    As a result of recent developments of mobile terminals, a mobile terminal has become a necessity of modern life. Mobile terminals have evolved into multimedia communication devices that can provide not only voice call services but also data transfer services and other supplementary services. More particularly, many users favor touch-enabled mobile terminals employing touch screen technology. 
         [0006]    A standard touch-enabled mobile terminal includes a single touch screen. However, an ever increasing number of applications running on a mobile terminal has aggravated a problem of screen size restrictions. To solve this problem, a mobile terminal having two touch screens has been developed. Currently, User Interface (UI) features for controlling a display on the two touch screens have not been established. 
         [0007]    Therefore, a need exists for a user interface feature for conveniently controlling two touch screens in a mobile terminal. 
       SUMMARY OF THE INVENTION 
       [0008]    An aspect of the present invention is to address at least the above-mentioned problems and/or disadvantages and to provide at least the advantages described below. Accordingly, an aspect of the present invention is to provide a method and apparatus for controlling a screen display of a mobile terminal including multiple touch screens in a manner enhancing user convenience. 
         [0009]    In accordance with an aspect of the present invention, a screen control method for a mobile terminal including multiple touch screens is provided. The method includes, displaying at least one application screen on the touch screens, detecting touch gestures made on the touch screens, identifying the detected touch gestures made on the touch screens, and changing at least one of application screens on the touch screens according to the identified touch gestures. 
         [0010]    In accordance with another aspect of the present invention, a mobile terminal is provided. The terminal includes multiple touch screens for detecting touch gestures and for displaying application screens, and a control unit for controlling the multiple touch screens to detect touch gestures, for identifying the detected touch gestures, and for changing at least one of the application screens on the touch screens according to the identified touch gestures. 
         [0011]    In an exemplary embodiment of the present invention, multiple touch screens may be controlled to change a screen display by simple touch gestures. The touch gestures are associated with intuitive actions of a user, thereby appealing to emotional sensitivity in the use of a mobile terminal. 
         [0012]    Other aspects, advantages, and salient features of the invention will become apparent to those skilled in the art from the following detailed description, which, taken in conjunction with the annexed drawings, discloses exemplary embodiments of the invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]    The above and other aspects, features, and advantages of certain exemplary embodiments of the present invention will be more apparent from the following description taken in conjunction with the accompanying drawings, in which: 
           [0014]      FIG. 1  illustrates a mobile terminal including two touch screens according to an exemplary embodiment of the present invention; 
           [0015]      FIG. 2  is a block diagram of a mobile terminal including two touch screens according to an exemplary embodiment of the present invention; 
           [0016]      FIG. 3  is a flowchart illustrating a screen control method for a mobile terminal including multiple touch screens according to an exemplary embodiment of the present invention; 
           [0017]      FIG. 4  is a flowchart illustrating a screen control method for a mobile terminal including multiple touch screens according to an exemplary embodiment of the present invention; 
           [0018]      FIG. 5A  depicts a screen display change on a first touch screen and a second touch screen in response to downward touch-point move gestures according to an exemplary embodiment of the present invention; 
           [0019]      FIG. 5B  depicts a screen display change on a first touch screen and a second touch screen in response to upward touch-point move gestures according to an exemplary embodiment of the present invention; 
           [0020]      FIG. 6  is a flowchart illustrating a screen control method for a mobile terminal including multiple touch screens according to an exemplary embodiment of the present invention; 
           [0021]      FIG. 7A  depicts a screen display change on a first touch screen and a second touch screen in response to upward touch-point move gestures according to an exemplary embodiment of the present invention; 
           [0022]      FIG. 7B  depicts a screen display change on a first touch screen and a second touch screen in response to downward touch-point move gestures according to an exemplary embodiment of the present invention; 
           [0023]      FIG. 8  is a flowchart illustrating a screen control method for a mobile terminal including multiple touch screens according to an exemplary embodiment of the present invention; 
           [0024]      FIG. 9A  depicts a screen display change on a first touch screen and a second touch screen in response to upward touch-point move gestures according to an exemplary embodiment of the present invention; 
           [0025]      FIG. 9B  depicts a screen display change on a first touch screen and a second touch screen in response to downward touch-point move gestures according to an exemplary embodiment of the present invention; 
           [0026]      FIG. 10  is a flowchart illustrating a screen control method for a mobile terminal including multiple touch screens according to an exemplary embodiment of the present invention; 
           [0027]      FIG. 11A  depicts a screen display change on a first touch screen and a second touch screen in response to upward touch-point move gestures according to an exemplary embodiment of the present invention; 
           [0028]      FIG. 11B  depicts a screen display change on a first touch screen and a second touch screen in response to downward touch-point move gestures according to an exemplary embodiment of the present invention; 
           [0029]      FIG. 12  is a flowchart illustrating a screen control method for a mobile terminal including multiple touch screens according to an exemplary embodiment of the present invention; 
           [0030]      FIG. 13A  depicts a screen display change on a first touch screen and a second touch screen in response to a downward touch-point move gesture made on a first touch screen and an upward touch-point move gesture made on a second touch screen according to an exemplary embodiment of the present invention; 
           [0031]      FIG. 13B  depicts a screen display change on a first touch screen and a second touch screen in response to an upward touch-point move gesture made on a first touch screen and a downward touch-point move gesture made on a second touch screen according to an exemplary embodiment of the present invention; 
           [0032]      FIG. 14  is a flowchart illustrating a screen control method for a mobile terminal including multiple touch screens according to an exemplary embodiment of the present invention; and 
           [0033]      FIGS. 15A and 15B  depict a screen display change on a first touch screen and a second touch screen according to an exemplary embodiment of the present invention. 
       
    
    
       [0034]    Throughout the drawings, it should be noted that like reference numbers are used to depict the same or similar elements, features, and structures. 
       DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS 
       [0035]    The following description with reference to the accompanying drawings is provided to assist in a comprehensive understanding of exemplary embodiments of the invention as defined by the claims and their equivalents. It includes various specific details to assist in that understanding but these are to be regarded as merely exemplary. Accordingly, those of ordinary skill in the art will recognize that various changes and modifications of the embodiments described herein can be made without departing from the scope and spirit of the invention. In addition, descriptions of well-known functions and constructions may be omitted for clarity and conciseness. 
         [0036]    The terms and words used in the following description and claims are not limited to the bibliographical meanings, but, are merely used by the inventor to enable a clear and consistent understanding of the invention. Accordingly, it should be apparent to those skilled in the art that the following description of exemplary embodiments of the present invention is provided for illustration purpose only and not for the purpose of limiting the invention as defined by the appended claims and their equivalents. 
         [0037]    It is to be understood that the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to “a component surface” includes reference to one or more of such surfaces. 
         [0038]    Exemplary embodiments of the present invention provide a mobile terminal. However, the present invention is not limited thereto, and is applicable to any touch-enabled device. The mobile terminal according to an exemplary embodiment of the present invention is a touch-enabled terminal and may include any information and communication device, such as a mobile communication terminal, a Portable Multimedia Player (PMP), a Personal Digital Assistant (PDA), a smart phone, a Moving Picture Expert Group (MPEG)-1 or 2 Audio Layer 3 (MP3) player, and the like. 
         [0039]      FIG. 1  illustrates a mobile terminal including two touch screens according to an exemplary embodiment of the present invention. 
         [0040]    The mobile terminal according to an exemplary embodiment of the present invention provides a folder type mobile terminal with two touch screens that are exposed to the outside when opened. However, the present invention is not limited thereto, and may be applied to other types of mobile terminals. For example, the present invention may be applied to a slide type mobile terminal, which exposes one touch screen to the outside when closed and exposes two touch screens when opened. 
         [0041]    Referring to  FIG. 1 , reference symbol [a] depicts an external appearance of the mobile terminal  100  in a closed state, and reference symbol [b] depicts the external appearance of the mobile terminal  100  in an opened state. The mobile terminal  100  is composed of a first body  101  and a second body  102 . The first body  101  includes a first touch screen  120  at one side, and the second body  102  includes a second touch screen  130  at one side. In an exemplary implementation, the mobile terminal  100  may have more than two display units. That is, an additional display unit may be installed on the other side of the first body  101 , and an additional display unit may be installed on the other side of the second body  102 . As indicated by reference symbol [b], the mobile terminal  100  may output a web browser screen on the first touch screen  120  and second touch screen  130 . The web browser screen corresponds to a case in which a single application screen is displayed on the two touch screens  120  and  130 . Internal components of the mobile terminal  100  will be described below. 
         [0042]      FIG. 2  is a block diagram of a mobile terminal including two touch screens according to an exemplary embodiment of the present invention. 
         [0043]    Referring to  FIG. 2 , the mobile terminal  100  includes a wireless communication unit  110 , a first touch screen  120 , a second touch screen  130 , an audio processing unit  140 , a key input unit  150 , a storage unit  160 , and a control unit  170 . 
         [0044]    The wireless communication unit  110  transmits and receives data for wireless communication of the mobile terminal  100 . The wireless communication unit  110  may include a radio frequency transmitter for upconverting the frequency of a signal to be transmitted and for amplifying the signal, and a radio frequency receiver for low-noise amplifying a received signal and for downconverting the frequency of the signal. The wireless communication unit  110  may receive data through a wireless channel and forward the received data to the control unit  170 , and may transmit data from the control unit  170  through the wireless channel. 
         [0045]    The first touch screen  120  includes a first touch sensor  121  and a first display  122 . The first touch sensor  121  recognizes a user&#39;s touch, and may be implemented using a capacitive sensor, a resistive sensor, an infrared sensor or a pressure sensor. In an exemplary implementation, any sensor capable of detecting contact or pressure may be utilized as the first touch sensor  121 . The first touch sensor  121  generates a touch signal corresponding to a user touch and transmits the touch signal to the control unit  170 . The touch signal includes coordinate data of the touch point. When the user makes a touch-point move gesture, the first touch sensor  121  generates a touch signal including coordinate data describing the path of the touch-point move and forwards the generated touch signal to the control unit  170 . In an exemplary implementation, a “touch-point move” gesture may correspond to a “flick” action in which a corresponding touch point moves at a speed greater than a preset threshold or to a “drag” action in which the corresponding touch point moves at a speed less than the preset threshold. 
         [0046]    The first display  122  may be implemented using Liquid Crystal Display (LCD) devices, Organic Light Emitting Diodes (OLED), or Active Matrix Organic Light Emitting Diodes (AMOLED). The first display  122  visually provides various information such as menus, input data and function-setting data to the user. The first display  122  may output a boot screen, an idle screen, a menu screen, a call handling screen, and other application screens for the mobile terminal  100 . 
         [0047]    The second touch screen  130  includes a second touch sensor  131  and a second display  132 . The second touch sensor  131  may be implemented using the same detecting means as the first touch sensor  121 . Similar to the first display  122 , the second display  132  may be implemented using LCD devices, OLEDs, or AMOLEDs, and may output an idle screen, a menu screen and other application screens for the mobile terminal  100 . 
         [0048]    In the following description, it is assumed that the first touch screen  120  is placed above the second touch screen  130  when the folder is open as indicated by reference symbol [b] of  FIG. 1 . 
         [0049]    The audio processing unit  140  may include a coder/decoder (i.e., a codec). The codec includes a data codec for processing packet data, and an audio codec for processing an audio signal such as a voice signal. The audio processing unit  140  converts a digital audio signal into an analog audio signal through the audio codec to reproduce the analog audio signal through a speaker, and also converts an analog audio signal from a microphone into a digital audio signal through the audio codec. 
         [0050]    The key input unit  150  generates a key signal corresponding to user manipulation and transmits the key signal to the control unit  170 . The key input unit  150  may include a keypad including alphanumeric keys, direction keys and function keys. When the mobile terminal  100  is fully manipulated through the first touch screen  120  and second touch screen  130 , the key input unit  150  may be removed from the mobile terminal  100 . 
         [0051]    The storage unit  160  stores programs and data necessary for the operation of the mobile terminal  100 . More particularly, the storage unit  160  stores information on touch gestures made on the first touch screen  120  and the second touch screen  130 , and information on screen changes related to the touch gestures. In an exemplary implementation, touch gestures may include a touch action composed of one or more tap operations, and a touch-point move action composed of a touch-and-move operation such as a flick and a drag. 
         [0052]    The control unit  170  controls overall operation of the mobile terminal  100 . More particularly, the control unit  170  includes a touch screen controller  171 . The touch screen controller  171  controls the first touch screen  120  and the second touch screen  130  to display at least one application screen. For example, the touch screen controller  171  may display a single application screen on both the first touch screen  120  and the second touch screen  130 , and may display different application screens on the first touch screen  120  and the second touch screen  130 . The touch screen controller  171  detects touch gestures made by the user on the first touch screen  120  and the second touch screen  130 , identifies a pattern of the touch gestures, and controls the first touch screen  120  and the second touch screen  130  to change at least one application screen according to the touch gesture pattern. For example, an application screen on only the first touch screen  120  may be changed, an application screen on only the second touch screen  130  may be changed, or application screens on both the first touch screen  120  and the second touch screen  130  may be changed. 
         [0053]    For identification of a touch gesture pattern, the touch screen controller  171  may determine the directions of touch-point move gestures made on the first touch screen  120  and the second touch screen  130 . For example, the touch screen controller  171  may determine that the touch-point move gestures made respectively on the first touch screen  120  and the second touch screen  130  are in the same direction. The touch screen controller  171  may determine that a touch-point move gesture made on the first touch screen  120  is in a direction toward the second touch screen  130  and another touch-point move gesture made on the second touch screen  130  is in a direction toward the first touch screen  120 . The touch screen controller  171  may determine that a touch-point move gesture made on the first touch screen  120  is in an opposite direction to the second touch screen  130  and another touch-point move gesture made on the second touch screen  130  is in an opposite direction to the first touch screen  120 . 
         [0054]    When the touch-point move gestures made respectively on the first touch screen  120  and the second touch screen  130  are in the same direction, the touch screen controller  171  may enlarge a first application screen displayed on the first touch screen  120  so that the first application screen is displayed on both the first touch screen  120  and the second touch screen  130 , or may enlarge a second application screen displayed on the second touch screen  130  so that the second application screen is displayed on both the first touch screen  120  and the second touch screen  130 . 
         [0055]    When the touch-point move gesture made on the first touch screen  120  is in a direction toward the second touch screen  130  and another touch-point move gesture made on the second touch screen  130  is in a direction toward the first touch screen  120 , the touch screen controller  171  may perform an application screen exchange so that a first application screen displayed on the first touch screen  120  is displayed on the second touch screen  130  and a second application screen displayed on the second touch screen  130  is displayed on the first touch screen  120 . 
         [0056]    When a touch-point move gesture made on the first touch screen  120  is in an opposite direction to the second touch screen  130  and another touch-point move gesture made on the second touch screen  130  is in an opposite direction to the first touch screen  120 , the touch screen controller  171  may display idle screens respectively on the first touch screen  120  and the second touch screen  130 . 
         [0057]      FIG. 3  is a flowchart illustrating a screen control method for a mobile terminal including multiple touch screens according to an exemplary embodiment of the present invention. 
         [0058]    Referring to  FIG. 3 , the touch screen controller  171  controls the first touch screen  120  and the second touch screen  130  to display one or more application screens in step  301 . An “application” refers to an executable program controlling a function supported by the mobile terminal  100 . For example, applications may be associated with functions for music playback, moving image playback, photography, web browsing, idle screen display, menu display, and the like. Application screens may include a music playback screen, a moving image playback screen, a web browsing screen, a message composition screen, an idle screen, a menu screen, and the like. 
         [0059]    The touch screen controller  171  may display a single application screen on both the first touch screen  120  and the second touch screen  130 , or may display different application screens on the first touch screen  120  and the second touch screen  130 . 
         [0060]    The touch screen controller  171  controls the first touch screen  120  and the second touch screen  130  to detect touch gestures made by the user in step  302 . In an exemplary implementation, it is assumed that the user makes a touch-point move gesture on the first touch screen  120  or the second touch screen  130  by touching and moving the touch point while maintaining contact. It is also assumed that the user makes touch gestures simultaneously on the first touch screen  120  and the second touch screen  130  at the same time. A threshold time for determining simultaneity of touch gestures is stored in the storage unit  160 . When the user makes a touch gesture on the second touch screen  130  within the threshold time after making a touch gesture on the first touch screen  120  or the user makes a touch gesture on the first touch screen  120  within the threshold time after making a touch gesture on the second touch screen  130 , the touch screen controller  171  considers the two touch gestures as gestures occurring simultaneously on the first touch screen  120  and the second touch screen  130 . Each of the first touch screen  120  and the second touch screen  130  generates a detecting signal corresponding to a touch gesture made by the user and transmits the detecting signal to the touch screen controller  171 . Here, the detecting signal includes coordinate data of the touch point. When the user makes a touch-point move gesture after a touch, each of the first touch screen  120  and the second touch screen  130  generates a detecting signal including coordinate data describing a path of the touch-point move and forwards the generated detecting signal to the touch screen controller  171 . The touch screen controller  171  receives detecting signals from the first touch screen  120  and the second touch screen  130  and obtains touch coordinates included in the detecting signals. 
         [0061]    The touch screen controller  171  identifies a pattern of touch gestures in step  303 . When the user makes touch-point move gestures while sustaining contact after touching the first touch screen  120  and the second touch screen  130 , the touch screen controller  171  receives detecting signals from the first touch screen  120  and the second touch screen  130 , obtains coordinate data describing the paths of the touch-point moves included in the detecting signals, and identifies the pattern of touch gesture based on the obtained coordinate data. The storage unit  160  stores information regarding touch gestures, and the touch screen controller  171  uses this information to identify the gesture made by the user. 
         [0062]    For identification of a touch gesture, the touch screen controller  171  may determine the directions of the touch-point move gestures made on the first touch screen  120  and the second touch screen  130 . For example, the touch screen controller  171  may determine that the touch-point move gestures made respectively on the first touch screen  120  and the second touch screen  130  are in the same direction. More specifically, the touch-point move gestures made on the first touch screen  120  and the second touch screen  130  may be an upward touch-point move gesture or a downward touch-point move gesture. 
         [0063]    The touch screen controller  171  may determine that a touch-point move gesture made on the first touch screen  120  is in a direction toward the second touch screen  130  and another touch-point move gesture made on the second touch screen  130  is in a direction toward the first touch screen  120 . More specifically, assuming that the first touch screen  120  is placed above the second touch screen  130  as indicated by reference symbol [b] of  FIG. 1 , a downward touch-point move gesture may be input to the first touch screen  120  and an upward touch-point move gesture may be input to the second touch screen  130 . 
         [0064]    The touch screen controller  171  may determine that a touch-point move gesture made on the first touch screen  120  is in an opposite direction to the second touch screen  130  and another touch-point move gesture made on the second touch screen  130  is in an opposite direction to the first touch screen  120 . More specifically, assuming that the first touch screen  120  is placed above the second touch screen  130  as indicated by reference symbol [b] of  FIG. 1 , an upward touch-point move gesture may be input to the first touch screen  120  and a downward touch-point move gesture may be input to the second touch screen  130 . 
         [0065]    The touch screen controller  171  controls the first touch screen  120  and the second touch screen  130  to change at least one of the displayed application screens according to the identified touch gesture pattern in step  304 . That is, an application screen on only the first touch screen  120  may be changed, an application screen on only the second touch screen  130  may be changed, or application screens on both the first touch screen  120  and the second touch screen  130  may be changed. 
         [0066]    More specifically, when the touch-point move gestures made respectively on the first touch screen  120  and the second touch screen  130  are in the same direction, the touch screen controller  171  may enlarge a first application screen displayed on the first touch screen  120  so that the first application screen is displayed on both the first touch screen  120  and the second touch screen  130 , or may enlarge a second application screen displayed on the second touch screen  130  so that the second application screen is displayed on both the first touch screen  120  and the second touch screen  130 . 
         [0067]    When a touch-point move gesture made on the first touch screen  120  is in a direction toward the second touch screen  130  and another touch-point move gesture made on the second touch screen  130  is in a direction toward the first touch screen  120 , the touch screen controller  171  may perform application screen exchange so that a first application screen displayed on the first touch screen  120  is displayed on the second touch screen  130  and a second application screen displayed on the second touch screen  130  is displayed on the first touch screen  120 . 
         [0068]    When a touch-point move gesture made on the first touch screen  120  is in an opposite direction to the second touch screen  130  and another touch-point move gesture made on the second touch screen  130  is in an opposite direction to the first touch screen  120 , the touch screen controller  171  may display idle screens respectively on the first touch screen  120  and the second touch screen  130 . 
         [0069]    A screen control method of the first touch screen and the second touch screen of the mobile terminal will be described below. 
         [0070]      FIG. 4  is a flowchart illustrating a screen control method for a mobile terminal including multiple touch screens according to an exemplary embodiment of the present invention. 
         [0071]    Referring to  FIG. 4 , the touch screen controller  171  controls the first touch screen  120  to display an application A screen, and controls the second touch screen  130  to display an application B screen in step  401 . The application A screen and the application B screen may correspond to one of a music playback screen, a moving image playback screen, a web browsing screen, a message composition screen, an idle screen, a menu screen, and the like. The user may execute the application A and the application B concurrently, and direct the touch screen controller  171  to display the application A screen and the application B screen respectively on the first touch screen  120  and the second touch screen  130 . 
         [0072]    The touch screen controller  171  controls the first touch screen  120  and the second touch screen  130  to detect touch gestures made by a user in step  402 . Each of the first touch screen  120  and the second touch screen  130  generates a detecting signal corresponding to a touch gesture made by the user and transmits the detecting signal including coordinate data of the touch point to the touch screen controller  171 . Upon reception of the detecting signal, the touch screen controller  171  obtains coordinate data of the touch point included in the detecting signal. In an exemplary implementation, it is assumed that the user makes touch-point move gestures in the same direction, for example, either an upwards direction or a downwards direction, while sustaining contact after touching the first touch screen  120  and the second touch screen  130 . 
         [0073]    The touch screen controller  171  identifies a pattern of touch gestures based on the obtained coordinate data, and determines whether the touch-point move gestures made on the first touch screen  120  and the second touch screen  130  are both in the downward direction in step  403 . If it is determined that the touch-point move gestures made on the first touch screen  120  and the second touch screen  130  are both in the downward direction, the touch screen controller  171  enlarges the application A screen displayed on the first touch screen  120  so that the application A screen is displayed on both the first touch screen  120  and the second touch screen  130  in step  404 . Here, on the second touch screen  130 , the application A screen is placed above the application B screen. The control unit  170  may run the application A and the application B in the foreground and in the background, respectively. 
         [0074]      FIG. 5A  depicts a screen display change on a first touch screen and a second touch screen in response to downward touch-point move gestures according to an exemplary embodiment of the present invention. 
         [0075]    Referring to  FIG. 5A , reference symbol [a] depicts a situation in which a user makes downward touch-point move gestures respectively on the first touch screen  120  and the second touch screen  130  while the application A screen is displayed on the first touch screen  120  and the application B screen is displayed on the second touch screen  130 . Reference symbol [b] of  FIG. 5A  depicts a screen display change after making the downward touch-point move gestures, in response to which the application A screen is displayed on both the first touch screen  120  and the second touch screen  130 . On the second touch screen  130 , the application B screen is placed below the application A screen. 
         [0076]    Referring back to  FIG. 4 , when the touch-point move gestures made on the first touch screen  120  and the second touch screen  130  are both not in the downward direction in step  403 , the touch screen controller  171  determines whether the touch-point move gestures made on the first touch screen  120  and the second touch screen  130  are both in the upward direction in step  405 . If it is determined that the touch-point move gestures made on the first touch screen  120  and the second touch screen  130  are both in the upward direction, the touch screen controller  171  enlarges the application B screen displayed on the second touch screen  130  so that the application B screen is displayed on both the first touch screen  120  and the second touch screen  130  in step  406 . Here, on the first touch screen  120 , the application B screen is placed above the application A screen. The control unit  170  may run the application B and the application A in the foreground and in the background, respectively. 
         [0077]      FIG. 5B  depicts a screen display change on a first touch screen and a second touch screen in response to upward touch-point move gestures according to an exemplary embodiment of the present invention. 
         [0078]    Referring to  FIG. 5B , reference symbol [a] depicts a situation in which the user makes upward touch-point move gestures respectively on the first touch screen  120  and the second touch screen  130  while the application A screen is displayed on the first touch screen  120  and the application B screen is displayed on the second touch screen  130 . Reference symbol [b] of  FIG. 5B  depicts a screen display change after making the upward touch-point move gestures, in response to which the application B screen is displayed on both the first touch screen  120  and the second touch screen  130 . On the first touch screen  130 , the application A screen is placed below the application B screen. 
         [0079]      FIG. 6  is a flowchart illustrating a screen control method for a mobile terminal including multiple touch screens according to an exemplary embodiment of the present invention. 
         [0080]    Referring to  FIG. 6 , the touch screen controller  171  controls the first touch screen  120  to display an application A screen above an application B screen, and controls the second touch screen  130  to display the application A screen in step  601 . Here, the control unit  170  may run the application A in the foreground using the first touch screen  120  and the second touch screen  130 , and run the application B in the background using the first touch screen  120 . Alternatively, the touch screen controller  171  may control the first touch screen  120  to display an application A screen, and control the second touch screen  130  to display the application A screen above an application B screen. 
         [0081]    The touch screen controller  171  controls the first touch screen  120  and the second touch screen  130  to detect touch gestures made by a user in step  602 . Each of the first touch screen  120  and the second touch screen  130  generates a detecting signal corresponding to a touch gesture made by the user and transmits the detecting signal including coordinate data of the touch point to the touch screen controller  171 . Upon reception of the detecting signal, the touch screen controller  171  obtains coordinate data of the touch point included in the detecting signal. In an exemplary implementation, it is assumed that the user makes touch-point move gestures in the same direction, for example, either an upwards direction or a downwards direction, while sustaining contact after touching the first touch screen  120  and the second touch screen  130 . 
         [0082]    The touch screen controller  171  identifies a pattern of touch gestures based on the obtained coordinate data, and determines whether the touch-point move gestures made on the first touch screen  120  and the second touch screen  130  are both in the upward direction in step  603 . If it is determined that the touch-point move gestures made on the first touch screen  120  and the second touch screen  130  are both in the upward direction, the touch screen controller  171  reduces the application A screen and moves the application B screen placed below the application A screen so that the application A screen is displayed on the first touch screen  120  and the application B screen is displayed on the second touch screen  130  in step  604 . Alternatively, in response to entering upward touch-point move gestures while the application A screen is displayed on both the first touch screen  120  and the second touch screen  130  and the application B screen is placed below the application A screen on the second touch screen  130 , the touch screen controller  171  may reduce the application A screen so that the application A screen is displayed on the first touch screen  120  and the application B screen is displayed on the second touch screen  130 . 
         [0083]      FIG. 7A  depicts a screen display change on a first touch screen and a second touch screen in response to upward touch-point move gestures according to an exemplary embodiment of the present invention. 
         [0084]    Referring to  FIG. 7A , reference symbol [a] depicts a situation in which a user makes upward touch-point move gestures respectively on the first touch screen  120  and the second touch screen  130  while the application A screen is displayed on the first touch screen  120  and the second touch screen  130  and the application B screen is placed below the application A screen on the first touch screen  120 . Reference symbol [b] of  FIG. 7A  depicts a screen display change after making the upward touch-point move gestures, in response to which the application A screen is displayed on the first touch screen  120  and the application B screen is displayed on the second touch screen  130 . 
         [0085]    Referring back to  FIG. 6 , when the touch-point move gestures made on the first touch screen  120  and the second touch screen  130  are both not in the upward direction in step  603 , the touch screen controller  171  determines whether the touch-point move gestures made on the first touch screen  120  and the second touch screen  130  are both in the downward direction in step  605 . If it is determined that the touch-point move gestures made on the first touch screen  120  and the second touch screen  130  are both in the downward direction, the touch screen controller  171  reduces the application A screen so that the application B screen is displayed on the first touch screen  120  and the application A screen is displayed on the second touch screen  130  in step  606 . Alternatively, in response to a downward touch-point move gestures while the application A screen is displayed on both the first touch screen  120  and the second touch screen  130  and the application B screen is placed below the application A screen on the second touch screen  130 , the touch screen controller  171  may reduce the application A screen and move the application B screen so that the application A screen is displayed on the second touch screen  130  and the application B screen is displayed on the first touch screen  120 . 
         [0086]      FIG. 7B  depicts a screen display change on the first touch screen and second touch screen in response to downward touch-point move gestures according to an exemplary embodiment of the present invention. 
         [0087]    Referring to  FIG. 7B , reference symbol [a] of  FIG. 7B  depicts a situation in which a user makes downward touch-point move gestures respectively on the first touch screen  120  and the second touch screen  130  while the application A screen is displayed on the first touch screen  120  and second touch screen  130  and the application B screen is placed below the application A screen on the first touch screen  120 . Reference symbol [b] of  FIG. 7B  depicts a screen display change after making the downward touch-point move gestures, in response to which the application A screen is displayed on the second touch screen  130  and the application B screen is displayed on the first touch screen  120 . 
         [0088]      FIG. 8  is a flowchart illustrating a screen control method for a mobile terminal including multiple touch screens according to an exemplary embodiment of the present invention. 
         [0089]    Referring to  FIG. 8 , the touch screen controller  171  controls the first touch screen  120  to display an application A screen above an application B screen, and controls the second touch screen  130  to display the application A screen above an application C screen in step  801 . Here, the control unit  170  may run the application A in the foreground using the first touch screen  120  and the second touch screen  130 , run the application B in the background using the first touch screen  120 , and run the application C in the background using the second touch screen  130 . 
         [0090]    The touch screen controller  171  controls the first touch screen  120  and the second touch screen  130  to detect touch gestures made by a user in step  802 . Each of the first touch screen  120  and the second touch screen  130  generates a detecting signal corresponding to a touch gesture made by the user and transmits the detecting signal including coordinate data of the touch point to the touch screen controller  171 . Upon reception of the detecting signal, the touch screen controller  171  obtains coordinate data of the touch point included in the detecting signal. In an exemplary implementation, it is assumed that the user makes touch-point move gestures in the same direction, for example, either an upwards direction or a downwards direction, while sustaining contact after touching the first touch screen  120  and the second touch screen  130 . 
         [0091]    The touch screen controller  171  identifies the pattern of touch gestures based on the obtained coordinate data, and determines whether the touch-point move gestures made on the first touch screen  120  and the second touch screen  130  are both in the upward direction in step  803 . If it is determined that the touch-point move gestures made on the first touch screen  120  and the second touch screen  130  are both in the upward direction, the touch screen controller  171  reduces the application A screen so that the application A screen is displayed on the first touch screen  120  and the application C screen below the application A screen is displayed on the second touch screen  130  in step  804 . Here, the control unit  170  may place the application C in the foreground on the second touch screen  130 . 
         [0092]      FIG. 9A  depicts a screen display change on a first touch screen and a second touch screen in response to upward touch-point move gestures according to an exemplary embodiment of the present invention. 
         [0093]    Referring to  FIG. 9A , reference symbol [a] depicts a situation in which a user makes upward touch-point move gestures respectively on the first touch screen  120  and the second touch screen  130  while the first touch screen  120  displays the application A screen above the application B screen and the second touch screen  130  displays the application A screen above the application C screen. Reference symbol [b] of  FIG. 9A  depicts a screen display change after making the upward touch-point move gestures, in response to which the application A screen is reduced and displayed on the first touch screen  120  and the application C screen is displayed on the second touch screen  130 . 
         [0094]    Referring back to  FIG. 8 , when the touch-point move gestures made on the first touch screen  120  and the second touch screen  130  are both not in the upward direction in step  803 , the touch screen controller  171  determines whether the touch-point move gestures made on the first touch screen  120  and the second touch screen  130  are both in the downward direction in step  805 . If it is determined that the touch-point move gestures made on the first touch screen  120  and the second touch screen  130  are both in the downward direction, the touch screen controller  171  reduces the application A screen so that the application B screen is displayed on the first touch screen  120  and the application A screen is displayed on the second touch screen  130  in step  806 . 
         [0095]      FIG. 9B  depicts a screen display change on a first touch screen and a second touch screen in response to downward touch-point move gestures according to an exemplary embodiment of the present invention. 
         [0096]    Referring to  FIG. 9B , reference symbol [a] of  FIG. 9B  depicts a situation in which a user makes downward touch-point move gestures respectively on the first touch screen  120  and the second touch screen  130  while the first touch screen  120  displays the application A screen above the application B screen and the second touch screen  130  displays the application A screen above an application C screen. Reference symbol [b] of  FIG. 9B  depicts a screen display change after making the downward touch-point move gestures, in response to which the application A screen is displayed on the second touch screen  130  and the application B screen is displayed on the first touch screen  120 . 
         [0097]      FIG. 10  is a flowchart illustrating a screen control method for a mobile terminal including multiple touch screens according to an exemplary embodiment of the present invention. 
         [0098]    Referring to  FIG. 10 , the touch screen controller  171  controls the first touch screen  120  and the second touch screen  130  to display an application A screen in step  1001 . In an exemplary implementation, no application screen is below the application A screen on the first touch screen  120  and the second touch screen  130 . Here, “application” screens do not include default screens, for example, an idle screen and a menu screen, provided in the mobile terminal  100  and may include screens (e.g., a music playback screen, a moving image playback screen, a web browsing screen, a message composition screen, and the like) related to applications explicitly run by the user. 
         [0099]    The touch screen controller  171  controls the first touch screen  120  and the second touch screen  130  to detect touch gestures made by the user in step  1002 . Each of the first touch screen  120  and the second touch screen  130  generates a detecting signal corresponding to a touch gesture made by the user and transmits the detecting signal including coordinate data of the touch point to the touch screen controller  171 . Upon reception of the detecting signal, the touch screen controller  171  obtains coordinate data of the touch point included in the detecting signal. In an exemplary implementation, it is assumed that the user makes touch-point move gestures in the same direction, for example, either an upwards direction or a downwards direction, while sustaining contact after touching the first touch screen  120  and the second touch screen  130 . 
         [0100]    The touch screen controller  171  identifies the pattern of touch gestures based on the obtained coordinate data, and determines whether the touch-point move gestures made on the first touch screen  120  and the second touch screen  130  are both in the upward direction in step  1003 . If it is determined that the touch-point move gestures made on the first touch screen  120  and the second touch screen  130  are both in the upward direction, the touch screen controller  171  reduces the application A screen so that the application A screen is displayed on the first touch screen  120  and an application menu screen is displayed on the second touch screen  130  in step  1004 . Here, the application menu screen refers to any default menu screen such as the main menu screen or a user settable menu screen set in the mobile terminal  100 . As described above, on the second touch screen  130 , no application screen is placed below the application A screen. When the application A screen reduces onto the first touch screen  120 , no application screen is displayed on the second touch screen  130 . In this case, the touch screen controller  171  displays the application menu screen on the second touch screen  130  to enable the user to run a desired application on the second touch screen  130 . When the user selects an application on the application menu screen, the touch screen controller  171  displays a screen related to the selected application on the second touch screen  130 . 
         [0101]      FIG. 11A  depicts a screen display change on a first touch screen and a second touch screen in response to upward touch-point move gestures according to an exemplary embodiment of the present invention. 
         [0102]    Referring to  FIG. 11A , reference symbol [a] depicts a situation in which the user makes upward touch-point move gestures respectively on the first touch screen  120  and the second touch screen  130  while both the first touch screen  120  and the second touch screen  130  display the application A screen. Reference symbol [b] of  FIG. 11A  depicts a screen display change after making the upward touch-point move gestures, in response to which the application A screen is reduced and displayed on the first touch screen  120  and the application menu screen is displayed on the second touch screen  130 . 
         [0103]    Referring back to  FIG. 10 , when the touch-point move gestures made on the first touch screen  120  and the second touch screen  130  are both not in the upward direction in step  1003 , the touch screen controller  171  determines whether the touch-point move gestures made on the first touch screen  120  and the second touch screen  130  are both in the downward direction in step  1005 . If it is determined that the touch-point move gestures made on the first touch screen  120  and the second touch screen  130  are both in the downward direction, the touch screen controller  171  reduces the application A screen so that the application A screen is displayed on the second touch screen  130  and the application menu screen is displayed on the first touch screen  120  in step  1006 . 
         [0104]      FIG. 11B  depicts a screen display change on a first touch screen and second touch screen in response to downward touch-point move gestures according to an exemplary embodiment of the present invention. 
         [0105]    Referring to  FIG. 11B , reference symbol [a] depicts a situation in which a user makes downward touch-point move gestures respectively on the first touch screen  120  and the second touch screen  130  while both the first touch screen  120  and the second touch screen  130  display the application A screen. Reference symbol [b] of  FIG. 11B  depicts a screen display change after making the downward touch-point move gestures, in response to which the application menu screen is displayed on the first touch screen  120  and the application A screen is displayed on the second touch screen  130 . 
         [0106]      FIG. 12  is a flowchart illustrating a screen control method for a mobile terminal including multiple touch screens according to an exemplary embodiment of the present invention. 
         [0107]    Referring to  FIG. 12 , the touch screen controller  171  controls the first touch screen  120  to display an application A screen, and controls the second touch screen  130  to display an application B screen in step  1201 . 
         [0108]    The touch screen controller  171  controls the first touch screen  120  and the second touch screen  130  to detect touch gestures made by a user in step  1202 . Each of the first touch screen  120  and the second touch screen  130  generates a detecting signal corresponding to a touch gesture made by a user and transmits the detecting signal including coordinate data of the touch point to the touch screen controller  171 . Upon reception of the detecting signal, the touch screen controller  171  obtains coordinate data of the touch point included in the detecting signal. In an exemplary implementation, it is assumed that the user makes touch-point move gestures in the opposite direction for example, either a downwards direction on the first touch screen  120  and an upwards on the second touch screen  130 , or an upwards direction on the first touch screen  120  and a downwards direction on the second touch screen  130 , while sustaining contact after touching the first touch screen  120  and the second touch screen  130 . 
         [0109]    The touch screen controller  171  identifies the pattern of touch gestures based on the obtained coordinate data, and determines whether the touch-point move gesture made on the first touch screen  120  is in the downward direction and the touch-point move gesture made on the second touch screen  130  is in the upward direction in step  1203 . If it is determined that the touch-point move gesture made on the first touch screen  120  is in the downward direction and the touch-point move gesture made on the second touch screen  130  is in the upward direction, the touch screen controller  171  switches the locations of the application A screen and the application B screen so that the application A screen is displayed on the second touch screen  130  and the application B screen is displayed on the first touch screen  120  in step  1204 . 
         [0110]      FIG. 13A  depicts a screen display change on a first touch screen and a second touch screen in response to a downward touch-point move gesture made on the first touch screen  120  and an upward touch-point move gesture made on the second touch screen  130  according to an exemplary embodiment of the present invention. 
         [0111]    Referring to  FIG. 13A , reference symbol [a] depicts a situation in which the user makes a downward touch-point move gesture on the first touch screen  120  and makes an upward touch-point move gesture on the second touch screen  130  while the first touch screen  120  displays the application A screen and the second touch screen  130  displays the application B screen. Reference symbol [b] of  FIG. 13A  depicts a screen display change after making the downward and upward touch-point move gestures, in response to which the application A screen is displayed on the second touch screen  130  and the application B screen is displayed on the first touch screen  120 . 
         [0112]    Referring back to  FIG. 12 , when the touch-point move gesture made on the first touch screen  120  is not in the downward direction or the touch-point move gesture made on the second touch screen  130  is not in the upward direction in step  1203 , the touch screen controller  171  determines whether the touch-point move gesture made on the first touch screen  120  is in the upward direction and the touch-point move gesture made on the second touch screen  130  is in the downward direction in step  1205 . If it is determined that the touch-point move gesture made on the first touch screen  120  is in the upward direction and the touch-point move gesture made on the second touch screen  130  is in the downward direction, the touch screen controller  171  displays idle screens on the first touch screen  120  and the second touch screen  130  in step  1206 . Here, the idle screen refers to a widget screen or a home screen. In response to the upward touch-point move gesture made on the first touch screen  120  and the downward touch-point move gesture made on the second touch screen  130 , the control unit  170  may terminate execution of the application A and the application B and enter the idle state, and the touch screen controller  171  displays idle screens on the first touch screen  120  and the second touch screen  130 . 
         [0113]      FIG. 13B  depicts a screen display change on a first touch screen and a second touch screen in response to an upward touch-point move gesture made on the first touch screen and a downward touch-point move gesture made on the second touch screen according to an exemplary embodiment of the present invention. 
         [0114]    Referring to  FIG. 13B , reference symbol [a] depicts a situation in which a user makes an upward touch-point move gesture on the first touch screen  120  and makes a downward touch-point move gesture on the second touch screen  130  while the first touch screen  120  displays the application A screen and the second touch screen  130  displays the application B screen. Reference symbol [b] of  FIG. 13B  depicts a screen display change after making the upward and downward touch-point move gestures, in response to which idle screens are displayed on the first touch screen  120  and the second touch screen  130 . 
         [0115]      FIG. 14  is a flowchart illustrating a screen control method for a mobile terminal including multiple touch screens according to an exemplary embodiment of the present invention. 
         [0116]    In an exemplary implementation, touch gestures are made on one of the first touch screen  120  and the second touch screen  130 . 
         [0117]    Referring to  FIG. 14 , the touch screen controller  171  controls a first touch screen  120  to display an application A screen above, and controls the second touch screen  130  to display the application B screen in step  1401 . 
         [0118]    The touch screen controller  171  determines whether a triple-tap gesture is made on the first touch screen  120  in step  1402 . Alternatively, the touch screen controller  171  may determine whether a triple-tap gesture is made on the second touch screen  130 , or determine whether more than one tap is entered on the first touch screen  120  or the second touch screen  130 . 
         [0119]    If it is determined that a triple-tap gesture is made on the first touch screen  120 , the touch screen controller  171  enlarges the application A screen so that the application A screen is displayed on both the first touch screen  120  and the second touch screen  130  in step  1403 . Here, on the second touch screen  130 , the application B screen is placed below the application A screen. 
         [0120]      FIGS. 15A and 15B  depict a screen display change on a first touch screen and a second touch screen according to an exemplary embodiment of the present invention. 
         [0121]    Referring to  FIG. 15A , reference symbol [a] depicts a situation in which a user makes a triple-tap gesture on the first touch screen  120  while the application A screen is displayed on the first touch screen  120  and the application B screen is displayed on the second touch screen  130 . Reference symbol [b] of  FIG. 15A  depicts a screen display change after making the triple-tap gesture, in response to which the application A screen is displayed on both the first touch screen  120  and the second touch screen  130 . On the second touch screen  130 , the application B screen is placed below the application A screen. 
         [0122]    Referring back to  FIG. 14 , the touch screen controller  171  determines whether a triple-tap gesture is made on the first touch screen  120  in step  1404 . If it is determined that a triple-tap gesture is made on the first touch screen  120 , the touch screen controller  171  reduces the application A screen so that the application A screen is displayed on the first touch screen  120  and the application B screen is displayed on the second touch screen  130  in step  1405 . 
         [0123]    Referring to  FIG. 15B , reference symbol [a] depicts a situation in which a user makes a triple-tap gesture on the first touch screen  120  while the first touch screen  120  displays the application A screen and the second touch screen  130  displays the application A screen above the application B screen. Reference symbol [b] of  FIG. 15B  depicts screen display change after making the triple-tap gesture, in response to which the application A screen is displayed on the first touch screen  120  and the application B screen is displayed on the second touch screen  130 . 
         [0124]    As apparent from the above description, exemplary embodiments of the present invention enable a user to control multiple touch screens and to change screen display by means of simple touch gestures. The touch gestures are associated with intuitive actions of the user, thereby appealing to emotional sensitivity in the use of a mobile terminal. 
         [0125]    While the invention has been shown and described with reference to certain exemplary embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined in the appended claims and their equivalents.