Patent Publication Number: US-2011065474-A1

Title: Mobile terminal

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     Pursuant to 35 U.S.C. §119(a), this application claims the benefit of earlier filing date and right of priority to Korean Application No. 10-2009-0086104, filed on Sep. 11, 2009, the contents of which is incorporated by reference herein in its entirety. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a mobile terminal having a solar cell. 
     2. Background of the Invention 
     Mobile devices are electronic devices which are portable and have at least one of voice and telephone call functions, information input and/or output functions, a data storage function and the like. 
     As it becomes multifunctional, the mobile device can be allowed to capture still images or moving images, play music or video files, play games, receive broadcast and the like, so as to be implemented as an integrated multimedia player. 
     Various attempts have been done for the multimedia device by hardware or software in order to implement such complicated functions. For example, a user interface environment is provided in order for users to easily and conveniently retrieve or select functions. 
     Conventionally, a power source to supply power to the mobile terminal has been a battery which is rechargeable via a home power source or the like. Consequently, when the battery is completely discharged, a burden to be in a home or office for charging is caused. As a recognition of pollution-free energy is raised, many attempts to mount a pollution-free power supply unit, such as a solar cell, to the mobile terminal are widely ongoing. 
     The solar cell generates electric energy in proportion to its size, so it may be difficult to be applied to a small mobile terminal. 
     SUMMARY OF THE INVENTION 
     Therefore, an object of the present invention is to provide a mobile terminal having solar cells, capable of allowing the solar cells to occupy a larger surface without lowering usability of the mobile terminal. 
     To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described herein, there is provided a mobile terminal including a terminal main body having a touch screen; and a flip cover foldably coupled to the terminal main body so as to have a closed state and an open state, and having a front surface and a rear surface, wherein the flip cover includes first and second solar cells disposed on the front surface and the rear surface respectively, wherein the flip cover comprises a display window configured to allow one region of the touch screen to be viewable in the closed state. 
     In accordance with one aspect of the present invention, the first solar cell may be formed on a first substrate and the second solar cell may be formed on a second substrate disposed in parallel to the first substrate. 
     In accordance with another aspect of the present invention, the first and second solar cells may be attached onto one surface of one substrate and the opposite surface thereto. 
     In accordance with another aspect of the present invention, the first and second solar cells may be integrally formed. 
     In accordance with another aspect of the present invention, the first and second solar cells may be connected to each other by being curved and extending from one end portion of the flip cover. 
     In accordance with another aspect of the present invention, the display window may be formed through the flip cover. 
     In accordance with another aspect of the present invention, the display window may further include a transparent panel. 
     In accordance with another aspect of the present invention, the flip cover may include a stopper for urging the terminal main body held at a preset angle with respect to a horizontal surface. 
     In accordance with another aspect of the present invention, the flip cover may have a size as large as being capable of obscuring the touch screen in the closed state. 
     In accordance with another aspect of the present invention, the mobile terminal may further include a receiver at one side of the flip cover. 
     In accordance with another aspect of the present invention, the flip cover may further include a housing formed to cover the first and second solar cells. 
     In accordance with another aspect of the present invention, the touch screen may be configured to output a charged state by the first and second solar cells. 
     In accordance with an embodiment of the present invention, a mobile terminal includes a terminal main body having a touch screen, and a flip cover foldably coupled to the terminal main body configured to have a closed state and an open state, the flip cover including a first solar cell disposed on a front surface, a second solar cell disposed on a rear surface, and a display window, where the display window allows one region of the touch screen to be viewable in the closed state. 
     In accordance with another embodiment of the present invention, a mobile terminal includes a terminal main body having a touch screen, and a flip cover foldably coupled to the terminal main body configured to have a closed state and an open state, the flip cover which includes a first solar cell disposed on a front surface, a second solar cell disposed on a rear surface, a display window formed through the flip cover configured to allow one region of the touch screen to be viewable in the closed state, a housing to configured to cover the first solar cell and the second solar cell, a stopper configured to control the terminal main body to be held at a preset angle with respect to a horizontal surface, and a receiver at one side of the flip cover. 
     The foregoing and other objects, features, aspects and advantages of the mobile terminal according to present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention. 
       In the drawings: 
         FIG. 1  is a block diagram of a mobile (portable) terminal in accordance with one embodiment of the present invention; 
         FIG. 2  is a front perspective view showing a closed configuration of a mobile terminal in accordance with the present invention; 
         FIG. 3  is a front perspective view showing an open configuration of the mobile terminal of  FIG. 2 ; 
         FIG. 4  is a perspective view showing another form of the mobile terminal in accordance with the present invention; 
         FIGS. 5A and 5B  are front views showing an operational state according to the present invention, wherein  FIG. 5A  shows a closed state of a flip cover, and  FIG. 5B  shows an open state of the flip cover; 
         FIG. 6A  is a view showing an operational state that a touch screen is viewable through a display window according to the present invention in the closed state of the flip cover; 
         FIG. 6B  is a view showing an operational state that numbers are output on the touch screen for dialing in the closed state of the flip cover; 
         FIG. 6C  is a view showing an operational state in one mode of the mobile terminal whose flip cover is open; 
         FIG. 7  is a sectional view of the flip cover according to the present invention; and 
         FIG. 8  is a sectional view showing another embodiment of the flip cover in accordance with the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Description will now be given in detail of preferred configurations of mobile devices according to the present invention, with reference to the accompanying drawings. Hereinafter, suffixes “module” and “unit or portion” for components used herein in description are merely provided only for facilitation of preparing this specification, and thus they are not granted a specific meaning or function. Hence, it should be noticed that “module” and “unit or portion” can be used together. 
       FIG. 1  is a block diagram of a mobile (portable) terminal in accordance with one embodiment of the present invention. 
     The mobile terminal  100  may comprise components, such as a wireless communication unit  110 , an Audio/Video (A/V) input unit  120 , a user input unit  130 , a sensing unit  140 , an output unit  150 , a memory  160 , an interface unit  170 , a controller  180 , a power supply  190  and the like. 
       FIG. 1  shows the mobile terminal  100  having various components, but it is understood that implementing all of the illustrated components is not a requirement. Greater or fewer components may alternatively be implemented. 
     Hereinafter, each component is described in sequence. 
     The wireless communication unit  110  may typically include one or more modules which permit wireless communications between the mobile terminal  100  and a wireless communication system or between the mobile terminal  100  and a network within which the mobile terminal  100  is located. For example, the wireless communication unit  110  may include a broadcast receiving module  111 , a mobile communication module  112 , a wireless internet module  113 , a short-range communication module  114 , a position location module  115  and the like. 
     The broadcast receiving module  111  receives a broadcast signal and/or broadcast associated information from an external broadcast managing entity via a broadcast channel. The broadcast channel may include a satellite channel and a terrestrial channel. The broadcast managing entity may indicate a server which generates and transmits a broadcast signal and/or broadcast associated information or a server which receives a pre-generated broadcast signal and/or broadcast associated information and sends them to the mobile terminal. The broadcast signal may be implemented as a TV broadcast signal, a radio broadcast signal, and a data broadcast signal, among others. The broadcast signal may further include a data broadcast signal combined with a TV or radio broadcast signal. 
     Examples of broadcast associated information may include information associated with a broadcast channel, a broadcast program, a broadcast service provider, and the like. The broadcast associated information may be provided via a mobile communication network, and received by the mobile communication module  112 . 
     The broadcast associated information may be implemented in various formats. For instance, broadcast associated information may include Electronic Program Guide (EPG) of Digital Multimedia Broadcasting (DMB), Electronic Service Guide (ESG) of Digital Video Broadcast-Handheld (DVB-H), and the like. 
     The broadcast receiving module  111  may be configured to receive digital broadcast signals transmitted from various types of broadcast systems. Such broadcast systems may include Digital Multimedia Broadcasting-Terrestrial (DMB-T), Digital Multimedia Broadcasting-Satellite (DMB-S), Media Forward Link Only (MediaFLO), Digital Video Broadcast-Handheld (DVB-H), Integrated Services Digital Broadcast-Terrestrial (ISDB-T), and the like. The broadcast receiving module  111  may be configured to be suitable for every broadcast system transmitting broadcast signals as well as the digital broadcasting systems. 
     Broadcast signals and/or broadcast associated information received via the broadcast receiving module  111  may be stored in a suitable device, such as a memory  160 . 
     The mobile communication module  112  transmits/receives wireless signals to/from at least one of network entities (e.g., base station, an external mobile terminal, a server, etc.) on a mobile communication network. Here, the wireless signals may include audio call signal, video (telephony) call signal, or various formats of data according to transmission/reception of text/multimedia messages. 
     The wireless internet module  113  supports wireless Internet access for the mobile terminal. This module may be internally or externally coupled to the mobile terminal  100 . Examples of such wireless Internet access may include Wireless LAN (WLAN) (Wi-Fi), Wireless Broadband (Wibro), Worldwide Interoperability for Microwave Access (Wimax), High Speed Downlink Packet Access (HSDPA) and the like. 
     The short-range communication module  114  denotes a module for short-range communications. Suitable technologies for implementing this module may include BLUETOOTH, Radio Frequency IDentification (RFID), Infrared Data Association (IrDA), Ultra-WideBand (UWB), ZigBee, and the like. 
     The position location module  115  denotes a module for detecting or calculating a position of a mobile terminal. An example of the position location module  115  may include a Global Position System (GPS) module. The GPS module may receive position information in cooperation with associated multiple satellites. Here, the position information may include coordinates information represented by latitude and longitude. For example, the GPS module can measure accurate time and distance respectively from more than three satellites so as to accurately calculate a current position of the mobile terminal based on such three different distances according to a triangulation scheme. A scheme may be used to obtain time information and distance information from three satellites and correct error by one satellite. Specifically, the GPS module can further obtain three-dimensional speed information and an accurate time, as well as position on latitude, longitude and altitude, from the position information received from the satellites. Wi-Fi Positioning System and/or Hybrid Positioning System may be applied as the position location module  115 . 
     The A/V input unit  120  is configured to provide audio or video signal input to the mobile terminal. The A/V input unit  120  may include a camera  121  and a microphone  122 . The camera  121  receives and processes image frames of still pictures or video obtained by image sensors in a video call mode or a capturing mode. The processed image frames may be displayed on a display unit  151 . 
     The image frames processed by the camera  121  may be stored in the memory  160  or transmitted to the exterior via the wireless communication unit  110 . Two or more cameras  121  may be provided according to the configuration of the mobile terminal. 
     The microphone  122  may receive an external audio signal while the mobile terminal is in a particular mode, such as a phone call mode, a recording mode, a voice recognition mode, or the like. This audio signal is processed into digital data. The processed digital data is converted for output into a format transmittable to a mobile communication base station via the mobile communication module  112  in case of the phone call mode. The microphone  122  may include assorted noise removing algorithms to remove noise generated in the course of receiving the external audio signal. 
     The user input unit  130  may generate input data input by a user to control the operation of the mobile terminal. The user input unit  130  may include a keypad, a dome switch, a touchpad (e.g., static pressure/capacitance), a jog wheel, a jog switch and the like. Especially, if a touch pad is layered with the display module  151  to be explained later, it is called as a touch screen. 
     The sensing unit  140  provides status measurements of various aspects of the mobile terminal. For instance, the sensing unit  140  may detect an open/close status of the mobile terminal, a change in a location of the mobile terminal  100 , a presence or absence of user contact with the mobile terminal  100 , the location of the mobile terminal  100 , acceleration/deceleration of the mobile terminal  100 , and the like, so as to generate a sensing signal for controlling the operation of the mobile terminal  100 . For example, regarding a slide-type mobile terminal, the sensing unit  140  may sense whether a sliding portion of the mobile terminal is open or closed. Other examples include sensing functions, such as the sensing unit  140  sensing the presence or absence of power provided by the power supply  190 , the presence or absence of a coupling or other connection between the interface unit  170  and an external device. Meanwhile, the sensing unit  140  may include a proximity sensor  141 , which will be explained later in relation to a touch screen. 
     The interface unit  170  may generally be implemented to interface the mobile terminal with external devices. The interface unit  170  may include, for example, wired/wireless headset ports, external charger ports, wired/wireless data ports, memory card ports, ports for coupling devices having an identification module, audio Input/Output (I/O) ports, video I/O ports, earphone ports, and the like. 
     The identification module may be configured as a chip for storing various information required to authenticate an authority to use the mobile terminal  100 , which may include a User Identity Module (UIM), a Subscriber Identity Module (SIM), and the like. Also, the device having the identification module (hereinafter, referred to as ‘identification device’) may be implemented in a type of smart card. Hence, the identification device can be coupled to the mobile terminal  100  via a port. The interface unit  170  may be configured to receive data or power from an external device to transmit it to each component inside the mobile terminal  100 , or may be configured to transmit data inside the mobile terminal  100  to an external device. 
     Also, the interface unit  170  may serve as a path for power to be supplied from an external cradle to the mobile terminal  100  when the mobile terminal  100  is connected to the external cradle or as a path for transferring various command signals input from the cradle by a user to the mobile terminal  100 . Such various command signals or power input from the cradle may operate as signals for recognizing that the mobile terminal  100  has accurately been mounted to the cradle. 
     The output unit  150  is configured to output an audio signal, a video signal or a tactile signal. The output unit  150  may include a display unit  151 , an audio output module  152 , an alarm  153  and the like. 
     The display unit  151  may output information processed in the mobile terminal  100 . For example, when the mobile terminal is operating in a phone call mode, the display unit  151  will provide a User Interface (UI) or a Graphic User Interface (GUI) which includes information associated with the call. As another example, if the mobile terminal is in a video call mode or a capturing mode, the display unit  151  may additionally or alternatively display images captured and/or received, UT, or GUI. 
     Meanwhile, as aforesaid, if the display unit  151  and a touch pad are layered with each other to configure a touch screen, the display unit  151  may be used as an input device as well as an output device. The display unit  151  may be implemented using, for example, at least one of a Liquid Crystal Display (LCD), a Thin Film Transistor-Liquid Crystal Display (TFT-LCD), an Organic Light-Emitting Diode (OLED), a flexible display, a three-dimensional (3D) display, or the like. 
     Some of such displays  151  may be implemented as a transparent type or an optical transparent type through which the exterior is visible, which is referred to as ‘transparent display’. A representative example of the transparent display may include a Transparent OLED (TOLED), and the like. The display unit  151  may be implemented in two or more in number according to a configured aspect of the mobile terminal  100 . For instance, the mobile terminal  100  may simultaneously include an external display module (not shown) and an internal display module (not shown). The touch screen may be implemented to detect even an touch input pressure as well as a touched position and area. 
     A proximity sensor  141  may be arranged inside the touch screen, or near the touch screen. The proximity sensor  141  indicates a sensor to sense presence or absence of an object approaching to a surface to be sensed, or an object disposed near a surface to be sensed, by using an electromagnetic field or infrared rays without a mechanical contact. The proximity sensor  141  has a longer lifespan and a more enhanced utility than a contact sensor. 
     The proximity sensor  141  may include a transmissive type photoelectric sensor, a direct reflective type photoelectric sensor, a mirror reflective type photoelectric sensor, a high-frequency oscillation proximity sensor, a capacitance type proximity sensor, a magnetic type proximity sensor, an infrared rays proximity sensor, and so on. 
     Among others, explaining a principle as to how the high frequency oscillation type proximity sensor operates, when an object to be detected becomes close to a sensor detection surface in a state of oscillating a high frequency from an oscillatory circuit, oscillatory amplitude of the oscillatory circuit is attenuated or stopped. Such change is converted into an electrical signal to detect an existence of the object to be detected. Thus, even if any material other than metal is positioned between the high frequency oscillation type proximity touch and the object to be detected, a proximity switch may detect the object to be detected without any interruption of the material. 
     Even without the proximity sensor  141  mounted, if an electrostatic touch screen is provided, the proximity of a pointer can be detected based upon the change in an electric field due to the proximity of the pointer. 
     Therefore, if the pointer is located near the touch screen without being actually contacted with each other, the location of the pointer and the distance (gap) between the pointer and the touch screen can be detected. Hereinafter, for the sake of brief explanation, a status that the pointer is positioned to be proximate onto the touch screen without contact will be referred to as ‘proximity touch’, whereas a status that the pointer substantially comes in contact with the touch screen will be referred to as ‘contact touch’. For the position corresponding to the proximity touch of the pointer on the touch screen, such position corresponds to a position where the pointer faces perpendicular to the touch screen upon the proximity touch of the pointer. 
     The proximity sensor  141  senses proximity touch, and proximity touch patterns (e.g., distance, direction, speed, time, position, moving status, etc.). Information relating to the sensed proximity touch and the sensed proximity touch patterns may be output onto the touch screen. 
     The audio output module  152  may output audio data received from the wireless communication unit  110  or stored in the memory  160 , in a call-receiving mode, a call-placing mode, a recording mode, a voice recognition mode, a broadcast reception mode, and so on. The audio output module  152  may output audio signals relating to functions performed in the mobile terminal  100 , e.g., sound alarming a call received or a message received, and so on. The audio output module  152  may include a receiver, a speaker, a buzzer, and so on. 
     The alarm  153  outputs signals notifying occurrence of events from the mobile terminal  100 . The events occurring from the mobile terminal  100  may include call received, message received, key signal input, touch input, and so on. The alarm  153  may output not only video or audio signals, but also other types of signals such as signals notifying occurrence of events, for example, in a vibration manner. Alternatively, when a key signal is input, the alarm  153  may output a vibration in response to a feedback of the key signal input, accordingly, a user can recognize the event generation via the output vibration. A signal for notifying the event generation may be output through the display unit  151  or the audio output module  152 . 
     The memory  160  may store a program for the processing and control of the controller  180 . Alternatively, the memory  160  may temporarily store input/output data (e.g., phonebook data, messages, still images, video and the like). Also, the memory  160  may store data related to various patterns of vibrations and audio output upon the touch input on the touch screen. 
     The memory  160  may be implemented using any type of suitable storage medium including a flash memory type, a hard disk type, a memory card type (e.g., SD or DX memory), Random Access Memory (RAM), Static Random Access Memory (SRAM), Read-Only Memory (ROM), magnetic memory, magnetic disk, optical disk, and the like. Also, the mobile terminal  100  may operate a web storage which performs the storage function of the memory  160  on the Internet. 
     The controller  180  typically controls the overall operations of the mobile terminal  100 . For example, the controller  180  performs the control and processing associated with telephony calls, data communications, video calls, and the like. The controller  180  may include a multimedia module  181  which provides multimedia playback. The multimedia module  181  may be configured as part of the controller  180  or as a separate component. 
     The controller  180  can perform a pattern recognition processing so as to recognize writing or drawing input on the touch screen as text or image. 
     The power supply  190  provides power required by various components under the control of the controller  180 . The provided power may be internal power, external power, or combination thereof. 
     The power supply  190  may include a battery  191  and first and second solar cells  240 ,  250  so as to generate power by itself and also allows the battery  191  to be charged with the generated electricity (power). The power charged in the battery  191  may be supplied upon running each component or circuit of the mobile terminal  100  under the control of the controller  180 . 
     The controller  180 , as will be explained later, may be configured to turn on or off a driving unit for running the first solar cell  240  or the second solar cell  250 , in response to opening or closing of a flip cover  202 . Also, the controller  180  may selectively run the first or second solar cell  240 ,  250  according to a quantity of power generated, in an open state of the flip cover  202 . 
     Various embodiments described herein may be implemented in a computer-readable medium using, for example, software, hardware, or some combination thereof. 
     For a hardware implementation, the embodiments described herein may be implemented within one or more Application Specific Integrated Circuits (ASICs), Digital Signal Processors (DSPs), Digital Signal Processing Devices (DSPDs), other electronic units designed to perform the functions described herein, or a selective combination thereof. In some cases, such embodiments are implemented by the controller  180 . 
     For software implementation, the embodiments such as procedures and functions may be implemented together with separate software modules each of which performs at least one of functions and operations. The software codes can be implemented with a software application written in any suitable programming language. Also, the software codes may be stored in the memory  160  and executed by the controller  180 . 
     The mobile terminal according to the present invention has been described in the aspect of components according to functions. Hereinafter, description will be given in more detail of the mobile terminal according to the present invention from the perspective of its components according to an outer appearance of the mobile terminal. 
       FIG. 2  is a front perspective view showing a closed configuration of a mobile terminal in accordance with the present invention, and  FIG. 3  is a front perspective view showing an open configuration of the mobile terminal of  FIG. 2 . 
     Referring to  FIGS. 2 and 3 , a mobile terminal  200  according to the present invention may include a terminal main body  201  and a flip cover  202  foldably coupled to the terminal main body  201 . 
     The terminal main body  201  may be provided within a case thereof with various modules or components for mobile communications or devices associated with input and output. 
     Referring to  FIG. 3 , a front surface of the terminal main body  201  is shown, having a touch screen  210 , an audio output unit  211 , an image input unit  216 , a front key  212  and the like. 
     The touch screen  210  may display visible information and be implemented as an LCD module, an OLED module, an e-paper and the like. In addition, the touch screen  210  may include a touch detecting unit allowing a touch input. Accordingly, when a portion on the touch screen  210  is touched, data (information, content) corresponding to the touched portion is input. Examples of the data input in the touch manner may include characters, numbers, menu items to be instructed or designated in various modes, and the like. The touch detecting unit may be formed to be transparent such that the touch screen  210  can be viewed therethrough. The touch detecting unit may also include a structure for enhancing visibility of the touch screen  210  at a bright place. Referring to  FIG. 3 , the touch screen  210  may occupy most of the front surface of the terminal main body  201 . 
     The audio output unit  211  may be implemented as a receiver which delivers a calling sound (conversation on a phone) to a user&#39;s ear or outputs various alarm sounds or reproduction sounds of multimedia. 
     The side surface of the terminal main body  201  is shown, having a side key  214 , an interface unit  215 , an audio input unit  213  and the like. 
     A front key  212  and the side key  214  may be referred to as a user input unit or a manipulation unit, and allow input of commands for controlling operations of the mobile terminal  200 . In the aspect of the functionality, the front key  212  may be configured to input commands such as START, END, SCROLL or the like, and the side key  214  may be configured to input commands, such as controlling the image input unit  216 , adjusting an audio sound output from the audio output unit  211 , converting the touch screen  210  into a touch-sensitive mode or the like. The front key  212  and the side key  214  may be manipulable by a user in any tactile manner. 
     The audio input unit  213  may be implemented, for example, as a microphone, so as to allow input of user&#39;s voice, other sounds and the like. 
     The interface unit  215  may be disposed at the side surface of the terminal main body  201 . The interface unit  215  may interface the mobile terminal  200  and external devices so as to allow data exchange therebetween or the like. For example, the interface unit  215  may be at least one of a wired/wireless access terminal for earphones, a short-range communication port (e.g., IrDA port, BLUETOOTH port, wireless Lan port, and the like), and power supply terminals for supplying power to the mobile terminal. The interface unit  215  may be a card socket for accommodating an external card such as Subscriber Identification Module (SIM), User Identity Module (UIM), memory card for storing information, or the like. 
     Referring to  FIGS. 2 and 3 , the flip cover  202  is connected to the terminal main body  201  via a hinge unit  205 , so it can be implemented in various states.  FIG. 2  shows a first state in which the flip cover  202  is completely overlaid on the terminal main body  201 , which may be referred to as ‘closed (folded) state,’ and  FIG. 3  shows a second state in which the flip cover  202  is rotated from the terminal main body  201  by a specific angle (e.g., an angle large enough to dial), which may be referred to as ‘open (unfolded) state.’ Here, the rotational angle of the flip cover  202  to open the same may be variously set. 
     The hinge unit  205  may include an elastic member which applies an elastic force to the flip cover  202  in a direction to close the flip cover  202 , and also applies the elastic force to the flip cover  202  when switching the flip cover  202  from the closed state into the open state. For folding the flip cover  202  with respect to the terminal main body  201 , a link element, a member made of rubber, a wrinkled neck and the like may alternatively be employed, in addition to the hinge unit  205  shown in  FIG. 2  or  3 . 
     A first solar cell  240  and a second solar cell  250  may be disposed on an outer surface of the flip cover  202  and an inner surface which is obscured. The outer surface of the flip cover  202  may be always exposed irrespective of opening or closing of the flip cover  202 , so the first solar cell  240  may be configured to collect solar rays and generate power even in the closed state of the flip cover  202 . On the other hand, the second solar cell  250  may be disposed to be operable in the open state of the flip cover  202 . 
     In the open state, at least one of the first solar cell  240  and the second solar cell  250  of the flip cover  202  may be operated. If sufficient solar rays or light emitted from an artificial lamp are radiated onto both surfaces of the flip cover  202 , both the first and second solar cells  240  and  250  may be operated so as to increase a charging speed. 
     Also, as one example, in the open state of the flip cover  202 , one of the first and second solar cells  240  and  250 , which is present on a surface receiving strong solar rays, is operated and another solar cell present on a surface receiving weak solar rays is restricted from being operated, thereby minimizing power consumption due to driving the undesired solar cell. 
     A quantity of power generated may depend on areas of the solar cells  240 ,  250 , so the flip cover  202  may be formed with an area corresponding to the terminal main body  201  so as to maximize the areas of the solar cells  240 ,  250 . The solar cells  240 ,  250  may also be disposed to occupy most of the area of the flip cover  202  for increase in the quantity of power generated. 
     A display window  220  for allowing a portion of the touch screen  210  to be viewable in the closed state may be formed at one side of the first solar cell  240 . The display window  220  may be made of a transparent material, such as glass, plastic, etc. or be realized as a through hole. Referring to  FIGS. 2 and 3 , the display window  220  is exemplarily implemented as the through hole. In addition, the display window  220  may be implemented by using a separate display unit (e.g., LCD, LED, OLED, etc.). 
     The display window  220  may be formed to be relatively smaller than the solar cells  240 ,  250  which require a large area. That is, the display window  220  may be formed as small as possible in size allowing for notification of a terminal state in various modes. 
     As one example according to the present invention, a sound hole  221  may be formed above the first solar cell  240  so as to urge a user hear call conversation even in the closed state of the flip cover  202 . Referring to  FIG. 3 , the sound hole  221  is present to correspond to the receiver or speaker  211  formed at the upper end of the terminal main body  201 , so as to urge the user hear sounds output through the speaker  211 . A speaker unit  218 , as shown in  FIG. 3 , may separately be disposed to urge the user hear the call conversation in the open state of the flip cover  202 . 
       FIG. 4  is a perspective view showing another form of the mobile terminal in accordance with the present invention. 
     The mobile terminal  200  shown in  FIG. 4  is substantially the same as the previous embodiment in that the flip cover  202  is formed at the terminal main body  201 . 
     However, the state that the flip cover  202  is open from the terminal main body  201  is different from that illustrated in  FIG. 3 . That is, the flip cover  202  may serve as a ‘holder’ for allowing the terminal main body  201  to maintain a preset angle from the ground. 
     To this end, at least one portion of the terminal main body  201  or the flip cover  202  is shown, having a stopper  230  for restricting the flip cover  202  from being further rotated from the terminal main body  201 . Referring to  FIG. 4 , the stopper  230  may be formed to be protruded to the exterior of the terminal main body  201 . Alternatively, a stopper device may also be disposed within the hinge unit  205 . 
     As shown in  FIG. 4 , when the terminal main body  201  is supported by the flip cover  202  to be stood at a specific angle, the inner surface of the flip cover  202  faces the exterior. Accordingly, the operation of the second solar cell  250  can be prevented, so only the first solar cell  240  can be operated to generate power. 
     The electric energy generated by the first solar cell  240  is stored in the battery  217  mounted to the rear surface of the terminal main body  201 . The battery  217  may be mounted internally or externally. 
       FIG. 5A  shows a closed state of the flip cover, and  FIG. 5B  shows an open state of the flip cover. 
     As shown in  FIGS. 5A and 5B , the mobile terminal can be configured to generate power using solar rays in both the closed and open states of the flip cover  202  by virtue of the first solar cell  240  and the second solar cell  250  disposed on both surfaces of the flip cover  202 . That is, referring to  FIG. 5A , in the closed state of the flip cover  202 , the first solar cell  240  is allowed to be oriented toward solar rays, thereby enabling a power generation and a charging operation. Also, the mobile terminal according to the present invention may be configured to allow the power generation and the charging operation even while making a call by opening the flip cover  202 . Referring to  FIG. 5B , since the inner surface of the flip cover  202  is obstructed by a user&#39;s face during a call communication, the second solar cell  250  may be prevented from being used, whereas the first solar cell  240  may still be exposed so as to generate and charge power with solar rays even during the call communication. 
       FIG. 6A  is a view showing an operational state that a touch screen is viewable through a display window according to the present invention in the closed state of the flip cover. 
     The mobile terminal  200  may be set to block power supply to the touch screen  210  when a specific event is not generated. If the touch screen  210  is in a wake-up state, as shown in  FIG. 6A , an icon or graphic  260  which visibly indicates a power generation state by the first solar cell  240  may be output on the touch screen  210  viewable through the display window  220 . The icon or graphic  260  may be configured in various forms, such as figure, color or flickering pattern, to correspond to the strength of a current generated by the first solar cell  240 . 
       FIG. 6B  is a view showing an operational state that numbers are output on the touch screen for dialing in the closed state of the flip cover. 
     Referring to  FIG. 6B , even in the closed state of the flip cover  202 , numbers  265  which are touch-inputtable are output on the touch screen  210  for dialing. A user can simply enter a callee&#39;s phone number in the touching manner to place a call. During this process, the first solar cell  240  is still operated, and the situation is output by use of the graphic or icon  260 . 
       FIG. 6C  is a view showing an operational state in one mode of the mobile terminal whose flip cover  202  is open. Referring to  FIG. 6C , a menu list  262  including various inputtable menus and the like are output on the touch screen  210 , and the operation or non-operation of the solar cells  240 ,  250  according to the present invention and the power generation state thereof may be output on one side of the menu list  262  in the form of the icon or graphic  260 . 
       FIG. 7  is a sectional view of the flip cover according to the present invention. 
     Referring to  FIG. 7 , the flip cover  202  may include a housing  253  having a protection film  225  formed on each of the outer and inner surfaces of the flip cover  202  for protecting the solar cells  240 ,  250 . The first solar cell  240  and the second solar cell  250  may be disposed in parallel at one side and another side of the housing  253 . The housing  253  may be formed to be rigid or flexible. 
     Referring to  FIG. 7 , each of the first and second solar cells  240  and  250  may include a substrate  242 ,  252  and a cell portion  241 ,  251 . The substrate  242  of the first solar cell  240  and the substrate  252  of the second solar cell  250  are separated by the housing  253 , but rather they may have a sufficiently strong structure by virtue of the rigidity of the housing  253  interposed therebetween. The substrate  242  of the first solar cell  240  and the substrate  252  of the second solar cell  250  may be fabricated in a form of a flexible film. The substrates  242 ,  252  of the first and second solar cells  240  and  250  may also be integrally connected to each other by being bent at one side of the housing  253 , thereby being generally configured in a form of a folded substrate. Alternatively, the first solar cell  240  and the second solar cell  250  may be connected in series. 
       FIG. 8  is a sectional view showing another embodiment of the flip cover in accordance with the present invention. 
     As shown in  FIG. 8 , the cell portions  241 ,  251  configuring the first and second solar cells  240 ,  250  may be attached respectively onto an outer surface and an inner surface of one substrate  243 . That is, unlike the structure of  FIG. 7  using two separate substrates  242 ,  252 , this embodiment may implement the first solar cell  240  and the second solar cell  250  using the one substrate  243 . This configuration can decrease the thickness of the substrate  243  and the housing, so it may be advantageous for making the flip cover  202  slimmer. 
     Also, referring to  FIG. 8 , a display window  220 ′ is configured in the form of a transparent panel made of glass or plastic, for example. 
     As described above, with the structure of the mobile terminal according to the present invention, a flip cover, which is open and closed and has solar cells overall mounted thereon, may be coupled to a bar-type mobile terminal having a touch screen, and provided with a display window, thereby allowing a power generation and a charging operation at any time if there are solar rays irrespective of opening or closing of the flip cover, and enabling execution of an operation via the display window without opening the flip cover. 
     According to one embodiment of the present invention, the flip cover can be configured slimmer by employing a thin film type solar cell, and also be applied as an additional usage, such as a holder. 
     The configurations and methods of the mobile terminal in the aforesaid embodiments may not be limitedly applied, but such embodiments may be configured by a selective combination of all or part of each embodiment so as to derive many variations. 
     The foregoing embodiments and advantages are merely exemplary and are not to be construed as limiting the present disclosure. The present teachings can be readily applied to other types of apparatuses. This description is intended to be illustrative, and not to limit the scope of the claims. Many alternatives, modifications, and variations will be apparent to those skilled in the art. The features, structures, methods, and other characteristics of the exemplary embodiments described herein may be combined in various ways to obtain additional and/or alternative exemplary embodiments. 
     As the present features may be embodied in several forms without departing from the characteristics thereof, it should also be understood that the above-described embodiments are not limited by any of the details of the foregoing description, unless otherwise specified, but rather should be construed broadly within its scope as defined in the appended claims, and therefore all changes and modifications that fall within the metes and bounds of the claims, or equivalents of such metes and bounds are therefore intended to be embraced by the appended claims.